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991.
As a consequence of changing immigration policy over the past 50 years, contemporary Australia has a culturally diverse population. Focusing on Brisbane, one of Australia's smaller immigrant-receiving cities but where some 19 per cent of the population is born overseas, this study examines attitudes to and perceptions of culturally different ethnic (non-Anglo) immigrant groups. Emphasis is placed on patterns of tolerance and intolerance for the city as a whole, both in areas of contact and in areas of minimal contact. Findings show that variations in attitudes vary somewhat from commonly accepted socio-economic and age-based correlations (the lower the status or the older people are the less tolerant), depending on the particular mix of ethnic birthplace groups present. They also show levels of intolerance in areas of minimal contact, which is implicitly attributed to mass media influences. In light of these findings, a concluding plea is made for anti-intolerance strategies to be developed for cities that pay regard to the geography of attitude-forming contexts. 相似文献
992.
B.B. Maruthi Sridhar Robert K. Vincent Sheila J. Roberts Kevin Czajkowski 《International Journal of Applied Earth Observation and Geoinformation》2011
The accumulation of heavy metals in the biosolid amended soils and the risk of their uptake into different plant parts is a topic of great concern. This study examines the accumulation of several heavy metals and nutrients in soybeans grown on biosolid applied soils and the use of remote sensing to monitor the metal uptake and plant stress. Field and greenhouse studies were conducted with soybeans grown on soils applied with biosolids at varying rates. The plant growth was monitored using Landsat TM imagery and handheld spectroradiometer in field and greenhouse studies, respectively. Soil and plant samples were collected and then analyzed for several elemental concentrations. The chemical concentrations in soils and roots increased significantly with increase in applied biosolid concentrations. Copper (Cu) and Molybdenum (Mo) accumulated significantly in the shoots of the metal-treated plants. Our spectral and Landsat TM image analysis revealed that the Normalized Difference Vegetative Index (NDVI) can be used to distinguish the metal stressed plants. The NDVI showed significant negative correlation with increase in soil Cu concentrations followed by other elements. This study suggests the use of remote sensing to monitor soybean stress patterns and thus indirectly assess soil chemical characteristics. 相似文献
993.
An efficient forward model of the climate controls on interannual variation in tree-ring width 总被引:1,自引:1,他引:0
Susan E. Tolwinski-Ward Michael N. Evans Malcolm K. Hughes Kevin J. Anchukaitis 《Climate Dynamics》2011,36(11-12):2419-2439
We present a simple, efficient, process-based forward model of tree-ring growth, called Vaganov–Shashkin-Lite (VS-Lite), that requires as inputs only latitude and monthly temperature and precipitation. Simulations of six bristlecone pine ring-width chronologies demonstrate the interpretability of model output as an accurate representation of the climatic controls on growth. Ensemble simulations by VS-Lite of two networks of North American ring-width chronologies correlate with observations at higher significance levels on average than simulations formed by regression of ring width on the principal components of the same monthly climate data. VS-Lite retains more skill outside of calibration intervals than does the principal components regression approach. It captures the dominant low- and high-frequency spatiotemporal ring-width signals in the network with an inhomogeneous, multivariate relationship to climate. Because continuous meteorological data are most widely available at monthly temporal resolution, our model extends the set of sites at which forward-modeling studies are possible. Other potential uses of VS-Lite include generation of synthetic ring-width series for pseudo-proxy studies, as a data level model in data assimilation-based climate reconstructions, and for bias estimation in actual ring-width index series. 相似文献
994.
Time-lapse monitoring is a powerful tool for observing dynamic changes in the subsurface. In particular it offers the potential for achieving inversion results with increased fidelity through the inclusion of complementary information from multiple time-steps. This inclusion of complementary information can reduce the need for spatial smoothing, without adding inversion artifacts to the resulting images. Commonly used time-lapse inversion methods include the ratio method, cascaded time-lapse inversion, difference inversion and differencing independent inversions. We introduce two additional methods in which both time-lapse data sets are inverted simultaneously. In the first, called temporally constrained time-lapse inversion, inversion of both datasets is done under a single optimization procedure and constraints are added to the regularization to ensure that the changes from one time to another are smooth. In the second method, called simultaneous time-lapse inversion, the inversions at time 1 and time 2 are performed simultaneously and constraints of smoothness and closeness to a reference model are applied to the difference image produced at each iteration, and subsequently, the constraints are updated at each iteration. Through both a numerical and a field example we compare the results of common time-lapse inversion methods as well as the introduced approaches. We found that of the commonly used time-lapse inversion methods the difference inversion method produced the best resolution of time-lapse changes and was the most robust in the presence of noise. However, we found that the alternative approach of simultaneous time-lapse inversion produced the best reconstruction of modeled EC changes in the numerical example and easily interpretable high resolution difference images in the field example. Moreover, there was less tailoring of regularization parameters with our simultaneous time-lapse approach, suggesting that it will lend itself well to an automated inversion code. 相似文献
995.
Vessey Alexander F. Hodges Kevin I. Shaffrey Len C. Day Jonathan J. 《Climate Dynamics》2020,54(5):2777-2795
Climate Dynamics - The Arctic is becoming more accessible as sea ice extent continues to decline, resulting in higher human exposure to Arctic storms. This study compares Arctic storm... 相似文献
996.
Chen Kuang-Jung Chiu Bonbbon Wang Jee-Shiang Lee Cheng-Yu Lin Cheng-Horng Chao Kevin 《Natural Hazards》2011,58(3):1233-1252
A strong earthquake with a magnitude of 7.6 (M
L
= 7.3) occurred on September 21, 1999, in central Taiwan. In order to discern any potential precursors before this earthquake,
geomagnetic data at Lunping (LNP), Taiwan, Geomagnetic Observatory situated 100 km from the epicenter are examined using two
methods, i.e., the traditional induction arrows and complex demodulation. Our results show that the remarkable temporal variation
of real induction arrows appear to be strong prior to the great earthquake over the previous 24 months. After the great earthquake,
the magnitudes of induction arrows decreased to the normal (mean of 8 years) levels. In other words, the direction of real
induction arrows of the periods 30 and 20 min rotated 85° and 40° anticlockwise, respectively, before the Chi-Chi earthquake
and returned to mean direction of last 10 years after the earthquake. A horizontal source field model using the finite difference
method for 3-D shows that the variation of the real induction arrows might be ascribed to the conductivity variation body,
which is 5 km buried at the epicenter area of the Chi-Chi earthquake, changing its conductivity from 0.002S/m to 0.06 S/m.
The ratios of modulus (demodulated by using the complex demodulation method) over a period 12, and 8 h relative to the period
of 24 h reveal a remarkable change that appeared 4–5 months prior to this strong earthquake. They increased gradually from
the beginning of 1999 to August 1999 and decreased again to a (8 years) mean level after the strong earthquake occurrence.
We consider that the variation of the induction arrow might be ascribed to the conductivity anomaly, which is buried 5 km
at the south-east side of LNP with a conductivity change of 0.06 S/m. We propose that this elevation might be related to the
preparation process of the great earthquake. 相似文献
997.
Kevin P. Norton Friedhelm von Blanckenburg Roman DiBiase Fritz Schlunegger Peter W. Kubik 《International Journal of Earth Sciences》2011,100(5):1163-1179
Denudation rates from cosmogenic 10Be measured in quartz from recent river sediment have previously been used in the Central Alps to argue that rock uplift occurs
through isostatic response to erosion in the absence of ongoing convergence. We present new basin-averaged denudation rates
from large rivers in the Eastern and Southern European Alps together with a detailed topographic analysis in order to infer
the forces driving erosion. Denudation rates in the Eastern and Southern Alps of 170–1,400 mm ky−1 are within a similar range to those in the Central Alps for similar lithologies. However, these denudation rates vary considerably
with lithology, and their variability generally increases with steeper landscapes, where correlations with topographic metrics
also become poorer. Tertiary igneous rocks are associated with steep hillslopes and channels and low denudation rates, whereas
pre-Alpine gneisses usually exhibit steep hillslopes and higher denudation rates. Molasse, flysch, and schists display lower
mean basin slopes and channel gradients, and, despite their high erodibility, low erosion rates. Exceptionally low denudation
rates are also measured in Permian rhyolite, which has high mean basin slopes. We invoke geomorphic inheritance as a major
factor controlling erosion, such that large erosive glaciers in the late Quaternary cold periods were more effective in priming
landscapes in the Central Alps for erosion than in the interior Eastern Alps. However, the difference in tectonic evolution
of the Eastern and Central Alps potentially adds to differences in their geomorphic response; their deep structures differ
significantly and, unlike the Central Alps, the Eastern Alps are affected by ongoing tectonic influx due to the slow motion
and rotation of Adria. The result is a complex pattern of high mountain erosion in the Eastern Alps, which has evolved from
one confined to the narrow belt of the Tauern Window in late Tertiary time to one affecting the entire underthrust basement,
orogenic lid, and parts of the Southern Alps today. 相似文献
998.
Anne-Carlijn Alderkamp Véronique GarconHein J.W. de Baar Kevin R. Arrigo 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(9):943-955
We assessed whether short-term photoacclimation responses of natural phytoplankton populations in the Drake Passage (Southern Ocean) were affecting protection from photodamage as cells are mixed up to the surface from depth. To this end, we measured phytoplankton fluorescence characteristics and their ratio of xanthophyll cycle pigment to photosynthetic pigments within the upper mixed layer (UML) and in short-term deck incubation experiments. Phytoplankton within the UML photoacclimated by increasing their ratio of xanthophyll cycle (diadinoxanthin [dd] and diatoxanthin [dt]) pigments to chlorophyll a. The photoacclimation processes observed within the UML did, however, not influence the protection of phytoplankton from photodamage during short-term near-surface irradiance experiments. Exposure to near-surface irradiance resulted in photodamage in all experiments, regardless of the phytoplankton community composition and irradiance levels. Incubating phytoplankton for six hours at either 2% or 50% of surface irradiance prior to exposure to near-surface irradiance did not alter the photodamage characteristics. This suggests that short-term photoacclimation processes within the UML are not adequate to protect phytoplankton from photodamage when cells are mixed up to the surface from depth, and that repair of damaged photosystems is crucial for maintaining photosynthesis under fluctuating irradiance conditions, even at very low mean irradiance levels. Likely, continuously operating photoacclimation processes offset to some extent the negative effects of photodamage on photosynthetic performance, albeit with increased metabolic costs. 相似文献
999.
The evolution of the Oued es Seffaia alluvial fan during the last 50,000 years is analyzed in the light of chronometric data derived from AMS radiocarbon and optical dating techniques. These ages have enabled the temporal constraint of the distalward progression of the intersection point (the upper limit of the locus of deposition) which has resulted in the telescopic segmentation of the fan. Comparison of these data with the Late Quaternary climatic history of the Maghreb highlights several problems of interpretation; due both to our limited knowledge of regional palaeoclimates and of the response of dryland fluvial systems to climate changes. However, our data provide some evidence to suggest that fan incision and formation of telescopic segments occurs in response to changes from arid to less arid conditions, supporting the conclusions of some of the work from other areas. 相似文献
1000.