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161.
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J. A. Vorpahl E. G. Gibson P. B. Landecker D. L. McKenzie J. H. Underwood 《Solar physics》1975,45(1):199-216
132 soft X-ray flare events have been observed with The Aerospace Corporation/Marshall Space Flight Center S-056 X-ray telescope that was part of the ATM complement of instruments aboard Skylab. Analyses of these data are reported in this paper. The observations are summarized and a detailed discussion of the X-ray flare structures is presented. The data indicated that soft X-rays emitted by a flare come primarily from an intense well-defined core surrounded by a region of fainter, more diffuse emission. Loop structures are found to constitute a fundamental characteristic of flare cores and arcades of loops are found to play a more important role in the flare phenomena than previously thought. Size distributions of these core features are presented and a classification scheme describing the brightest flare X-ray features is proposed. The data show no correlations between the size of core features and: (1) the peak X-ray intensity, as indicated by detectors on the SOLRAD satellite; (2) the rise time of the X-ray flare event, or (3) the presence of a nonthermal X-ray component. An analysis of flare evolution indicates evidence for preliminary heating and energy release prior to the main phase of the flare. Core features are found to be remarkably stable and retain their shape throughout a flare. Most changes in the overall configuration seem to be the result of the appearance, disappearance or change in brightness of individual features, rather than the restructuring or re-orientation of these features. Brief comparisons with several theories are presented. 相似文献
164.
Chashei I. V. Lebedeva T. O. Tyul’bashev S. A. Subaev I. A. 《Astronomy Reports》2021,65(11):1150-1169
Astronomy Reports - A joint analysis of the monitoring data of interplanetary scintillations with solar and geophysical data showed that at the descending phase of the 24 solar activity cycle, the... 相似文献
165.
B. D. Dore 《Pure and Applied Geophysics》1968,71(1):118-131
Summary A formula is derived for the spatial attenuation of the two possible modes of oscilation of a two-layer, rotating system. If the long-wave approximation is made, it is found with reference to the internal mode that this formula disagrees with an earlier result obtained byRattray [8]2). 相似文献
166.
Vasil’ev D. Yu. Vodopyanov V. V. Zayzeva G. S. Zakirzyanov Sh. I. Semenov V. A. Sivokhip Zh. T. Chibilev A. A. 《Doklady Earth Sciences》2019,486(2):724-727
Doklady Earth Sciences - The results of long-term forecasting of the spring runoff in the Belaya River basin based on the water-balance model are presented. The structure and parameters of the... 相似文献
167.
Reactive barriers are passive and in situ ground water treatment systems. Heterogeneities in hydraulic conductivity (K) within the aquifer-reactive barrier system will result in higher flux rates, and reduced residence times, through portions of the barrier. These spatial variations in residence time will affect the treatment capacity of the barrier. A numerical flow model was used to evaluate the effects of spatial variations in K on preferential flow through barriers. The simulations indicate that the impact of heterogeneities in K will be a function of their location and distribution; the more localized the high K zone, the greater the preferential flow. The geometry of the reactive barrier will also strongly influence flow distribution. Aquifer heterogeneities will produce greater preferential flow in thinner barriers compared to thicker barriers. If the barrier K is heterogeneous, greater preferential flow will occur in thicker barriers. The K of the barrier will affect the flow distribution; decreasing the K of the barrier can result in more even distribution of flow. Results indicate that less variable flow will be attained utilizing thicker, homogeneous barriers. The addition of homogeneous zones to thinner barriers will be effective at redistributing flow only if installed immediately adjacent to both the up- and downgradient faces of the barrier. 相似文献
168.
V. D. Mats D. Yu. Shcherbakov I. M. Efimova 《Stratigraphy and Geological Correlation》2011,19(4):404-423
Independent methods of geological and molecular-biological chronologies have made it possible to define generally corresponding
stages in the geological and biological evolution of the environments and communities of Lake Baikal since the Late Cretaceous,
i.e., during the last 70 myr. All the abiotic elements drastically changed during geological evolution, with destruction of
existing and formation of new natural complexes. Nevertheless, some specific zones retained relicts of former settings. The
resulting present-day natural complex includes elements of different ages and geneses. Similar to different natural zones
of the present-day Earth, which are populated by different biocoenoses, stages in the development of abiotic elements are
also characterized by different faunal and floral assemblages. Some taxa were replaced by others, and the resulting aqueous
biota of Lake Baikal includes different-age and ecologically different elements. The oldest groups of Baikal organisms appeared
approximately 70 Ma ago, although the largest proportion of the lake biota started forming 4–3 Ma ago in response to the most
drastic changes in the abiotic elements of the environment. The youngest taxa appeared 1.8 to 0.15 Ma ago, i.e., during the
period when superdeep lake environments and mountainous glaciations were developing. The chronological coincidence of main
stages in development of abiotic and biotic elements of the nature indicates their relationships. Particular transformations
of abiotic elements and the probable mechanism of their influence on the evolution of living communities are also considered. 相似文献
169.
This paper shows how local spatial nonparametric prediction models can be applied to estimate volumes of recoverable gas resources
at individual undrilled sites, at multiple sites on a regional scale, and to compute confidence bounds for regional volumes
based on the distribution of those estimates. An approach that combines cross-validation, the jackknife, and bootstrap procedures
is used to accomplish this task. Simulation experiments show that cross-validation can be applied beneficially to select an
appropriate prediction model. The cross-validation procedure worked well for a wide range of different states of nature and
levels of information. Jackknife procedures are used to compute individual prediction estimation errors at undrilled locations.
The jackknife replicates also are used with a bootstrap resampling procedure to compute confidence bounds for the total volume.
The method was applied to data (partitioned into a training set and target set) from the Devonian Antrim Shale continuous-type
gas play in the Michigan Basin in Otsego County, Michigan. The analysis showed that the model estimate of total recoverable
volumes at prediction sites is within 4 percent of the total observed volume. The model predictions also provide frequency
distributions of the cell volumes at the production unit scale. Such distributions are the basis for subsequent economic analyses.
相似文献
Emil D. AttanasiEmail: |
170.