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461.
462.
Agapitus Ahamefule Amadi 《Geotechnical and Geological Engineering》2011,29(3):259-265
Long term competent performance of liner systems is a critical issue in the design and construction of waste repositories
due to adverse interactions associated with leachate generated by wastes. This study was conducted to verify the efficacy
of fly ash stabilization in enhancing compatibility between lateritic soil and municipal waste leachate. Applications investigated
include soil mixtures containing 0, 5, 10, 15, and 20% fly ash compacted at approximately 2% wet of optimum moisture content
with modified proctor energy. Baseline hydraulic conductivity was first established at every level of fly ash content by permeating
soil mixtures with tap water before permeation with leachate in a compaction mould permeameter using the falling head test
method. Results show that the trend in hydraulic conductivity of specimen containing 0% fly ash was characterized by a gradual
but erratic decrease which may suggests partial entry of the leachate cations into the double layer. Conversely, specimens
containing fly ash showed a general trend consisting of an initial drop in k (up to an order of magnitude) that was followed
by slight decrease sustained until k stabilized and later terminated. Above 10% fly ash content, the relatively high values
of k observed was not connected with the reactivity of the soil mixtures with leachate, rather it may be attributed to excessive
fly ash content that altered their textural and hydraulic properties. The result of this study is potentially significant
in the assessment of fly ash as a compatibility enhancing agent which can be admixed in barrier materials that are susceptible
to adverse reactions with the liquid to be contained. 相似文献
463.
464.
Hilkka Pellikka Jenni Rauhala Kimmo K. Kahma Tapani Stipa Hanna Boman Antti Kangas 《Natural Hazards》2014,74(1):197-215
We present four case studies of exceptional wave events of meteorological origin, observed on the Finnish coast in the summers of 2010 and 2011. Eyewitnesses report unusually rapid and strong sea-level variations (up to 1 m in 5–15 min) and strong oscillating currents during these events. High-resolution sea-level measurements confirm the eyewitness observations, but the oscillations recorded by tide gauges mostly have a considerably smaller amplitude. The oscillations coincide with sudden jumps in surface air pressure at coastal observation stations, related to the passage of squall lines or gust fronts. These fronts propagate above the sea at a resonant speed, allowing efficient energy transfer between the atmospheric disturbance and the sea wave that it generates. Thus, we interpret the observed sea-level oscillations as small meteotsunamis, long tsunami-like waves generated by meteorological processes and resonance effects. 相似文献
465.
466.
Optical and SEM observations of phosphorites reveal that mineralization is concentrated on ooids and micro-oncoids. The coated grains occur within microbial mats. Microbial mats represent the formational environment of the ooids and oncoids. Both coated grains and mats exhibit similar filamentous micro-organisms. The mat filaments show no fixed orientation and they merge with the concentrically oriented filaments of the coated grains. The branching nature and chlamydospore-like structures of filaments suggest that both mat and coated grains have been formed by fungi. Some coated grains appear to have been slightly disturbed and sometimes mobilized from their sites of formation due to separation from the parent mat resulting perhaps from contraction/fragmentation. The voids so created within the mat had been later filled with either micrite or sparite. 相似文献
467.
Zagidullin A. A. Usanin V. S. Petrova N. K. Nefedyev Yu. A. Andreev A. O. Gudkova T. V. 《Astronomy Reports》2020,64(12):1093-1106
Astronomy Reports - The work is devoted to the study of the physical libration of the Moon. Interest in the traditional topic related to the rotation of the Moon is stirred up by the activity of... 相似文献
468.
Doklady Earth Sciences - Based on the results of studying the lithological–geochemical features of the Upper Jurassic–Lower Cretaceous mudrocks and black shales in the Eastern Russian... 相似文献
469.
470.
Seasonal extreme wave statistics were reproduced by using the 25-km-grid global wave model of WAVEWATCH-III. The results showed that the simulated wave dataset for the present climate (1979-2009) was similar to Climate Forecast System Reanalysis (CFSR) wave data. Statistics such as the root mean squared error (RMSE) and correlation coefficient (CC) over the western North Pacific (WNP) basin were 0.5 m and 0.69 over the analysis domain. The largest trends and standard deviation were around the southern coast of Japan and western edge of the WNP. Linear regression analysis was employed to identify the relationship between the leading principal components (PCs) of significant wave heights (SWHs) in the peak season of July to September and sea surface temperature (SST) anomalies in the equatorial Pacific. The results indicated that the inter-annual variability of SWH can be associated with the El Niño-Southern Oscillation in the peak season. The CC between the first PC of the SWH and anomalies in the Nino 3.4 SST index was also significant at a 99% confidence level. Significant variations in the SWH are affected by tropical cyclones (TCs) caused by increased SST anomalies. The genesis and development of simulated TCs can be important to the variation in SWHs for the WNP in the peak season. Therefore, we can project the variability of SWHs through TC activity based on changes in SST conditions for the equatorial Pacific in the future. 相似文献