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11.
L. Goddard A. Kumar A. Solomon D. Smith G. Boer P. Gonzalez V. Kharin W. Merryfield C. Deser S. J. Mason B. P. Kirtman R. Msadek R. Sutton E. Hawkins T. Fricker G. Hegerl C. A. T. Ferro D. B. Stephenson G. A. Meehl T. Stockdale R. Burgman A. M. Greene Y. Kushnir M. Newman J. Carton I. Fukumori T. Delworth 《Climate Dynamics》2013,40(1-2):245-272
Decadal predictions have a high profile in the climate science community and beyond, yet very little is known about their skill. Nor is there any agreed protocol for estimating their skill. This paper proposes a sound and coordinated framework for verification of decadal hindcast experiments. The framework is illustrated for decadal hindcasts tailored to meet the requirements and specifications of CMIP5 (Coupled Model Intercomparison Project phase 5). The chosen metrics address key questions about the information content in initialized decadal hindcasts. These questions are: (1) Do the initial conditions in the hindcasts lead to more accurate predictions of the climate, compared to un-initialized climate change projections? and (2) Is the prediction model’s ensemble spread an appropriate representation of forecast uncertainty on average? The first question is addressed through deterministic metrics that compare the initialized and uninitialized hindcasts. The second question is addressed through a probabilistic metric applied to the initialized hindcasts and comparing different ways to ascribe forecast uncertainty. Verification is advocated at smoothed regional scales that can illuminate broad areas of predictability, as well as at the grid scale, since many users of the decadal prediction experiments who feed the climate data into applications or decision models will use the data at grid scale, or downscale it to even higher resolution. An overall statement on skill of CMIP5 decadal hindcasts is not the aim of this paper. The results presented are only illustrative of the framework, which would enable such studies. However, broad conclusions that are beginning to emerge from the CMIP5 results include (1) Most predictability at the interannual-to-decadal scale, relative to climatological averages, comes from external forcing, particularly for temperature; (2) though moderate, additional skill is added by the initial conditions over what is imparted by external forcing alone; however, the impact of initialization may result in overall worse predictions in some regions than provided by uninitialized climate change projections; (3) limited hindcast records and the dearth of climate-quality observational data impede our ability to quantify expected skill as well as model biases; and (4) as is common to seasonal-to-interannual model predictions, the spread of the ensemble members is not necessarily a good representation of forecast uncertainty. The authors recommend that this framework be adopted to serve as a starting point to compare prediction quality across prediction systems. The framework can provide a baseline against which future improvements can be quantified. The framework also provides guidance on the use of these model predictions, which differ in fundamental ways from the climate change projections that much of the community has become familiar with, including adjustment of mean and conditional biases, and consideration of how to best approach forecast uncertainty. 相似文献
12.
We made comparative studies of three tropical ox-bow lakes in India with different trophic states. The species number of zooplanktons
was negatively correlated with the degree of water eutrophication, and lakes of similar trophic status had higher similarity
of species. The most significant differences of species composition were observed with rotifers and zoobenthos. The density
and biomass of phytoplankton, rotifers, oligochaetes and chironomids tended to increase with increasing nutrients. We observed
a significant difference of dominant species in different waters, especially the eutrophic lake, which was dominated by a
few species of oligochaetes. The abundance of Tanypus bilobatus showed a highly significant correlation with the degree of eutrophication. Rotifers and zoobenthos showed considerably lower
biodiversity in the eutrophic lake. 相似文献
13.
Birendra Nath Ghosh Narinder Kumar Sharma Nurnabi Meherul Alam Raman Jeet Singh Gopal Prasad Juyal 《山地科学学报》2014,11(5):1208-1217
On farm bio-resource recycling has been given greater emphasis with the introduction of conservation agriculture specifically withclimate change scenarios in the mid-hills of the north-west Himalaya region(NWHR). Under this changing scenario, elevation, slope aspect and integrated nutrient management(INM) may affect significantly soil quality and crop productivity. A study was conducted during 2009-2010 to 2010-2011 at the Ashti watershed of NWHR in a rainfed condition to examine the influence of elevation, slope aspect and integrated nutrient management(INM) on soil resource and crop productivity. Two years of farm demonstration trials indicated that crop productivity and soil quality is significantly affected by elevation, slope aspect and INM. Results showed that wheat equivalent yield(WEY) of improved technology increased crop productivity by -20%-37% compared to the conventional system. Intercropping of maize with cowpea and soybean enhanced yield by another 8%-17%. North aspect and higher elevation increased crop productivity by 15%-25% compared to south aspect and low elevation(except paddy). Intercropping of maize with cowpea and soybean enhanced yield by another 8%-15%. Irrespective of slope, elevation and cropping system, the WEY increased by -30% in this region due to INMtechnology. The influence of elevation, slope aspect and INM significantly affected soil resources(SQI) and soil carbon change(SCC). SCC is significantly correlated with SQI for conventional(R2 = 0.65*), INM technology(R2 = 0.81*) and for both technologies(R2 = 0.73*). It is recommended that at higher elevation.(except for paddy soils) with a north facing slope, INM is recommended for higher crop productivity; conservation of soil resources is recommended for the mid hills of NWHR; and single values of SCC are appropriate as a SQI for this region. 相似文献
14.
Prasanta Kumar Nayak Birendra Kumar Mohapatra Prem Prakash Singh 《Resource Geology》2014,64(4):387-394
Banded iron formation (BIF) of the Gorumahisani–Sulaipat–Badampahar (GSB) belt in Singhbhum Craton, India, consists predominantly of magnetite. This BIF is intruded by a magnetite dyke. The magnetite dyke is massive and compact with minor sulphide minerals while the host banded magnetite ore, a component of the BIF, shows thin lamination. The magnetite ore of the dyke is fine to medium grained and exhibits interlocking texture with sharp grain boundaries, which is different from the banded magnetite that is medium to coarse grained and show irregular martitised and goethitised grain boundaries. Relics of Fe–Ca–Mn–Mg‐carbonate and iron silicates (grunerite and cummingtonite) are observed in the banded magnetite. The intrusive magnetite is distinctly different in minor, trace and REE geochemistry from the banded magnetite. The banded magnetite contains higher amounts of Si, Al, Mn, Ca, Mg, Sc, Ga, Nb, Zr, Hf, Co, Rb and Cu. In contrast, the massive magnetite is enriched in Cr, Zn, V, Ni, Sr, Pb, Y, Ta, Cs and U with higher abundance of HREE. In the chondrite normalized plot, the massive magnetite shows a slight positive Eu anomaly while the banded ore does not show any Eu anomaly. Field disposition, morphology, mineralogy and chemistry show that the intrusive magnetite dyke is of igneous origin, while magnetite in BIF formed from a carbonate protolith through the process of sedimentation. 相似文献
15.
Pravin Kumar Sharma Nalin Kumar Johri Gagan Behari Raut G. Rangaswamy Brahma Kishore Pandey Anand Kumar Chaturvedi 《Journal of the Geological Society of India》2018,91(3):281-289
Characterization of the Panandhro lignite deposits from western Indian state of Gujarat, based on the geochemical and palynological evidences, has been performed to assess the floral composition, maturity and hydrocarbon potential of the sequence. Elementally, the lignites consist of moderate carbon, low hydrogen and moderate sulfur contents. The samples are characterized by high TOC contents (lignite: av. 46.43 wt.%, resin: 62.47 wt.%). The average HI values for the lignite is 136 mg HC/g TOC, and that of the associated resin is 671 mg HC/g TOC. The highest Tmax is recoded in lignite (422°C) and lowest in the resin (39°C) samples. The FTIR spectrum of lignite is characterized by highly intense OH stretching peak ~3350 cm-1, aliphatic CHx stretching peaks between 3000-2800 cm-1, aromatic C=O stretching and an aromatic C=C stretching. The spectrum of resin shows strongest absorption due to aliphatic CHx stretching between 2940-2915 cm-1 and 2870-2850 cm-1, and deformation by the medium peak between 1450 and 1650 cm-1. The recovered palynofloral assemblage indicates the dominance of angiosperm pollen grains with maximum abundance of Arecaceae family, and subdominant pteridophytic spores. Marine influence is indicated by the presence of abundant dinoflagellate cysts. The occurrence of flora from a variety of ecological niches suggests a luxuriant diverse vegetation pattern existed in the vicinity of depositional site under humid tropical conditions. The overall characteristics of the lignite deposits point towards their ability to generate (upon maturation) hydrocarbons as they have types III–II admixed kerogen (organic matters). 相似文献
16.
In this paper, lead-time and spatial dependence in skill for prediction of monthly mean climate variability is analyzed. The analysis is based on a set of extensive hindcasts from the Climate Forecast System at the National Centers for Environmental Prediction. The skill characteristics of initialized predictions is also compared with the AMIP simulations forced with the observed sea surface temperature (SST) to quantify the role of initial versus boundary conditions in the prediction of monthly means. The analysis is for prediction of monthly mean SST, precipitation, and 200-hPa height. The results show a rapid decay in skill with lead time for the atmospheric variables in the extratropical latitudes. Further, after a lead-time of approximately 30?C40?days, the skill of monthly mean prediction is essentially a boundary forced problem, with SST anomalies in the tropical central/eastern Pacific playing a dominant role. Because of the larger contribution from the atmospheric internal variability to monthly time-averages (compared to seasonal averages), skill for monthly mean prediction associated with boundary forcing is also lower. The analysis indicates that the prospects of skillful prediction of monthly means may remain a challenging problem, and may be limited by inherent limits in predictability. 相似文献
17.
The paper examines the quality of Tropical Rainfall Monitoring Mission (TRMM) 3B42 V7 precipitation product to simulate the streamflow using Soil Water Assessment Tool (SWAT) model for various rainfall intensities over the Himalayan region. The SWAT model has been set up for Gandak River Basin with 41 sub-basins and 420 HRUs. Five stream gauge locations are used to simulate the streamflow for a time span of 10 years (2000–2010). Daily streamflow for the simulation period is collected from Central Water Commission (CWC), India and Department of Hydrology and Meteorology (DHM), Nepal. The simulation results are found good in terms of Nash–Sutcliffe efficiency \((\hbox {NSE}) {>}0.65\), coefficient of determination \((R^{2}) {>}0.67\) and Percentage Bias \(\hbox {(PBIAS)}{<}15\%\), at each stream gauge sites. Thereafter, we have calculated the PBIAS and RMSE-observations standard deviation ratio (RSR) statistics between TRMM simulated and observed streamflow for various rainfall intensity classes, viz., light (\({<}7.5 \, \hbox {mm}/\hbox {d}\)), moderate (7.5 to 35.4 mm/d), heavy (35.5 to 124.4 mm/d) and extremely heavy (\({>}124.4 \, \hbox {mm}/\hbox {d}\)). The PBIAS and RSR show that TRMM simulated streamflow is suitable for moderate to heavy rainfall intensities. However, it does not perform well for light- and extremely-heavy rainfall intensities. The finding of the present work is useful for the problems related to water resources management, irrigation planning and hazard analysis over the Himalayan regions. 相似文献
18.
M. Vijayakumaran R. Venkatesan T. Senthil Murugan T.S. Kumar Dilip Kumar Jha M.C. Remany 《新西兰海洋与淡水研究杂志》2013,47(2):623-634
Pueruli and post‐pueruli, early juveniles and sub‐adults of the spiny lobster, Panulirus homarus and juveniles of P. ornatus were grown in different floating sea cages along the southeast coast of India from May 2003 to May 2007. The first type of cage had a galvanised iron pipe frame (2.0 m × 2.0 m × 1.2 m) with steel woven mesh and four inner detachable compartments (0.75 m × 0.75 m × 1.10 m). Fibre‐reinforced plastic was used subsequently to fabricate cages (1 m × 1 m × 1 m). Pueruli and post‐pueruli of P. homarus (1.58 ± 0.62 g SD), stocked at 60 individuals/m2, grew to an average weight of 123.10 ± 26.22 g in 266 days with a survival rate of 70%. Sub‐adults of P. homarus with an average weight (± SD) of 123.61 ± 29.26 g reached 341.25 ± 46.22 g in 225 days at a stocking density of 21 individuals/m2 with a survival of 73 ± 6%. The post‐pueruli grew by 0.46 ± 0.10 g per day with a specific growth rate (SGR) of 1.64, whereas sub‐adults had a growth rate of 0.97 ± 0.20 g per day with a SGR of 0.43. At a higher stocking density of 80 individuals/m2, juveniles (51.83 ± 10.32 g and 58.20 ± 28.22 g) of P. homarus recorded growth rates of 0.86 ± 0.25 (SGR 0.82) and 0.97 ± 0.34 g (SGR 0.96) per day. This study indicates that post‐pueruli of P. homarus can be grown to over 200 g in 12 months and up to 350 g in 16 to 17 months in sea cages. Juveniles (average weight 76.35 ± 34.50 g) of P. ornatus, reared with P. homarus at a stocking density of 80 individuals/m2, recorded a weight gain of 139 g in 155 days at arate of 0.89 ± 0.32 g per day with an SGR of 0.67. Marine live clam, Donax spp., was the main feed supplemented with the gastropod, Xancus pyrum, the green mussel, Perna viridis, marine crab (Charibdis sp.), squid (Loligo sp.), and fish such as clupeids and Leognathus sp. Pueruli and post‐pueruli settled in large numbers (up to 35 individuals/month in one cage) both inside and outside the cages. 相似文献
19.
Shiv S. Kumar 《Astrophysics and Space Science》1972,17(1):219-222
It is suggested that the minimum mass of a star at the time of its formation is approximately 0.01M
. Making use of this fact and the stellar mass functionF(M) M
–, it is found that the hidden mass (or the missing mass) in the solar neighborhood may be explained by the presence of a large number of invisible stars of very low mass (0.01M
M<0.07M
). 相似文献
20.