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171.
172.
Jonathan MP Roy PD Thangadurai N Srinivasalu S Rodríguez-Espinosa PF Sarkar SK Lakshumanan C Navarrete-López M Muñoz-Sevilla NP 《Marine pollution bulletin》2011,62(4):845-850
A survey on the metal concentrations (As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V, Zn) in beach water and sediments is reported from the tourist destination of Acapulco city on the Pacific coast of Mexico. The concentration of dissolved trace metals (DTMs) in beach water and acid leachable trace metals (ALTMs) in sediments indicated that they are anthropogenic in nature due to the increased tourist activities in the crowded beach locations. The statistical analysis indicates Fe and Mn play a major role as metal scavengers in both the medium (water and sediment) and the higher value of other metals is site specific in the study area, indicating that they are transported from the local area. Comparison results suggest that the beach water quality has deteriorated more than the sediments and special care needs to be taken to restore the beach quality. 相似文献
173.
Suresh Kumar N. R. Patel Aditi Sarkar V. K. Dadhwal 《Journal of the Indian Society of Remote Sensing》2013,41(3):609-618
The present study demonstrated the methodology to assess agro-climatic suitability of the soybean crop through integration of crop suitability based on FAO framework of land evaluation and biophysical (water limited) yield potential in the rainfed agro-ecosystem. A long term climatic database (1980–2003) was prepared to compute decadal rainfall and temperature variations of 13 IMD stations in part of Madhya Pradesh state. The climatic database was used in soil water balance software–BUDGET to compute crop specific length of growing period (LGP) and biophysical production potential such as water limited crop yield potential of each soil types for soybean crop. Water limited crop yield potential of soils were found to be varied from 33 to 100 and LGP ranged from 65 to 180 days in the area. FAO based land suitability was analyzed in association with the water limited yield potential for better appraisal of land potential and assess their suitability in rainfed area. FAO based land suitability indicated 2.45 % area as highly suitable and 57.49 % area as moderately suitable. However, integration of water limited crop yield potential with FAO based land suitability lead to agro-climatic suitability analysis indicated 17.60 % and 40.03 % area, respectively as highly suitable and moderately suitable. FAO based land evaluation showed 88.13 % of plains as moderately suitable whereas agro-climatic suitability indicated only 47.79 %. Agro-climatic suitability analysis revealed undulating plateau and undulating plains as most suitable for soybean crop. 相似文献
174.
AbstractA physically-based hillslope hydrological model with shallow overland flow and rapid subsurface stormflow components was developed and calibrated using field experiments conducted on a preferential path nested hillslope in northeast India. Virtual experiments were carried out to perform sensitivity analysis of the model using the automated parameter estimation (PEST) algorithm. Different physical parameters of the model were varied to study the resulting effects on overland flow and subsurface stormflow responses from the theoretical hillslopes. It was observed that topographical shapes had significant effects on overland flow hydrographs. The slope profiles, surface storage, relief, rainfall intensity and infiltration rates primarily controlled the overland flow response of the hillslopes. Prompt subsurface stormflow responses were mainly dominated by lateral preferential flow, as soil matrix flow rates were very slow. Rainfall intensity and soil macropore structures were the most influential parameters on subsurface stormflow. The number of connected soil macropores was a more sensitive parameter than the size of macropores. In hillslopes with highly active vertical and lateral preferential pathways, saturation excess overland flow was not evident. However, saturation excess overland flow was generated if the lateral macropores were disconnected. Under such conditions, rainfall intensity, duration and preferential flow rate governed the process of saturation excess overland flow generation from hillslopes.
Editor D. Koutsoyiannis; Associate editor C. Perrin 相似文献
175.
H. Hamzehloo H. Rahimi I. Sarkar M. Mahood H. Mirzaei Alavijeh E. Farzanegan 《Journal of Seismology》2010,14(2):169-195
We analyze the strong motion accelerograms of the moderate (M
w = 6.1), March 31, 2006, Darb-e-Astane earthquake of western Iran and also those of one of its prominently recorded, large
(M
w = 5.1) foreshock and (M
w = 4.9) aftershock. (1) Using derived SH-wave spectral data, we first objectively estimate the parameters W o\mathit{\Omega} _{\rm o} (long period spectral level), f
c (corner frequency) and Q(f) (frequency dependent, average shear wave quality factor), appropriate for the best-fit Brune ω
− 2 spectrum of each of these three events. We then perform a non-linear least square analysis of the SH-wave spectral data to
provide approximate near-field estimates of the strike, dip, and rake of the causative faults and also the seismic moment,
moment magnitude, source size, and average stress drop of these three events. (2) In the next step, we use these approximate
values and an empirical Green’s function approach, in an iterative manner, to optimally model the strong ground motion and
rupture characteristics of the main event in terms of peak ground acceleration/velocity/displacement and duration of ground
shaking and thereby provide improved, more reliable estimates of the causative fault parameters of the main event and its
asperities. Our near-field estimates for both the main moderate event and the two smaller events are in good conformity with
the corresponding far-field estimates reported by other studies. 相似文献
176.
S. Sarkar N. K. Goel B. S. Mathur 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(3):411-423
Estimation of design rainfall intensity is crucial for design and planning of water resources engineering projects. The intent
of the present study is to develop regional IDF curves for Tehri-Garhwal Himalayan region in India, wherein numbers of hydropower
projects are in planning and execution stage. Self Recording Rain Gauge (SRRG) stations are generally not so frequent in the
project locations. Under this situation, the engineers are forced to use regional intensity duration frequency (IDF) curves.
Under this study, four stations viz. Tehri M.T.Lab, Mukhim, Pilkhi and Dhuttu were available with SRRG data. These data are
used to develop the regional IDF curve for entire Tehri-Garwal region. After selection of the most intensive storms, return
periods has been determined using regionalized L-moment method. After developing IDF curves for above four raingauge stations,
Thiessen Ploygon method is applied to find out average IDF curve. To show the spatial variability, Isopluvial maps have been
generated using ArcGIS and a relation equation has been developed. 相似文献
177.
Ankur Sarkar Debasish Sarkar Madhurima Gupta Chiranjib Bhattacharjee 《洁净——土壤、空气、水》2012,40(8):830-837
Polyvinyl alcohol (PVA), the major constituent of desizing water constituting 45% of the total BOD load has a significant environmental impact owing to its poor biodegradability. In order to prevent PVA from being discharged by the effluent stream, modern textile industries opt for membrane based separation techniques using ultrafiltration so that the recovery and recycle of PVA in tandem could be achieved. However, the process of ultrafiltration is still not widely accepted as expected due to the well‐known non‐idealities of concentration polarization and pore blockage. In this article, design and performance characterization of a lab‐scale novel shear enhanced ultrafiltration unit, named as spinning basket membrane (SBM) module are discussed. The proposed module is unique in terms of its inbuilt cleaning facility eliminating the effects of polarization and subsequent periodic fouling leading to its uninterrupted production operation. The test fluid, necessarily a solution of PVA was treated in the proposed module under different parametric conditions with polyvinylidene fluoride (PVDF) membranes of two different molecular weight cut‐off (50 and 100 kDa). After 2 h of continuous operation the permeate flux was observed to be within 95–97% of the respective initial fluxes. Such performance is rarely been attained in practice. Hence, the novelty of the present research is achieved. Considering the performance of the present module in terms of flux regeneration and product recovery, it may be regarded as an efficient device and can be potentially deployed for cleaning of other industrial wastewater. 相似文献
178.
179.
Sejuti Naha Biswas Dibyendu Rakshit Santosh Kumar Sarkar Ranjit Kumar Sarangi Kamala Kanta Satpathy 《Marine pollution bulletin》2014
A multispecies bloom caused by the centric diatoms, viz. Coscinodiscus radiatus, Chaetoceros lorenzianus and the pennate diatom Thalassiothrix frauenfeldii was investigated in the context of its impact on phytoplankton and microzooplankton (the loricate ciliate tintinnids) in the coastal regions of Sagar Island, the western part of Sundarban mangrove wetland, India. Both number (15–18 species) and cell densities (12.3 × 103 cells l−1 to 11.4 × 105 cells l−1) of phytoplankton species increased during peak bloom phase, exhibiting moderately high species diversity (H′ = 2.86), richness (R′ = 6.38) and evenness (E′ = 0.80). The diatom bloom, which existed for a week, had a negative impact on the tintinnid community in terms of drastic changes in species diversity index (1.09–0.004) and population density (582.5 × 103 to 50 × 103 ind m−3). The bloom is suggested to have been driven by the aquaculture activities and river effluents resulting high nutrient concentrations in this region. An attempt has been made to correlate the satellite remote sensing-derived information to the bloom conditions. MODIS-Aqua derived chlorophyll maps have been interpreted. 相似文献
180.
Statistical characterizations of rainfall structure over two tropical stations in southern India are reported in this paper based on the 2-year rainfall data. The statistical characterizations has been based on cumulative distribution function, exceedance of threshold values, dependence of the intensity of rainfall on the event duration, seasonal variability, and worst months concept as well as diurnal variability. These results are needed to give the detailed insights to the system designers for the development of communication gadgets needed for better service, serve as a vital tool to estimate signal outages in a year over the region and for proper planning of radio communication in the region. Finally, the study shows that the recent International Telecommunications Union Recommendations (ITU-R) value underestimated rain rate for 0.01% exceedance for the two locations. 相似文献