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181.
A new equation of state for the Aral Sea is proposed. The equation expresses the dependency of the density on the temperature
and salinity. It corresponds to the contemporary salinity range and the ionic salt composition as observed in 2007. The equation
was obtained based on direct density measurements using a high precision vibration beam densimeter; therefore, it does not
rely on any a priory assumptions about the ionic composition. The accuracy of the density calculations from the new equation
of state significantly exceeds that from the extrapolation of the oceanic equation. 相似文献
182.
I. Xanthakis I. Liritzis B. Petropoulos C. Banos E. Sarris 《Earth, Moon, and Planets》1994,66(2):189-212
The atmospheric activity of Jupiter exhibits quasi-periodic character attributed to the stochastic nature of the involved mechanisms. Periodicities between 4–33 years are obtained employing four spectrum analysis methods, (power spectrum employing the Blackman-Tukey window, maximum entropy, Fourier, autocorrelation), whilst, their significance and their stationarity has been established with the application of general statistical tests (Kolmogorov-Smirnov, one sample and two sample test, randomness test, chi-square, various orders of autoregressive process, analysis of truncated records).Deceased. 相似文献
183.
萨尔托海蛇绿混杂岩是西准噶尔地区达拉布特蛇绿混杂岩带的重要组成部分,其形成时代和构造环境颇具争议。通过LA-ICP-MS锆石微区原位U-Pb同位素测年,获得其中辉长辉绿岩的 206Pb/238U 加权平均年龄为388.8±1.1 Ma,确定该蛇绿混杂岩形成于中泥盆世。岩石地球化学分析表明,纯橄岩(蛇纹岩)属于低Si、低碱、高Mg的变质橄榄岩,REE呈∑REE 偏低的平坦型分布模式,Cr、Ni和Co含量较高,变玄武岩属于高Ti、富Mg、富Fe、偏碱的拉斑系列,REE分布模式呈现 ∑REE 偏低、Eu异常不明显的平坦型曲线,微量元素分布模式为K、Cs、Th、Nb和P相对亏损的平坦型曲线,Zr/Nb比值低,总体表现出与E-MORB相似的特征。综合判断认为,萨尔托海蛇绿混杂岩形成于大陆裂谷向洋盆转化的构造环境,类似于"红海式"洋盆,为进一步深入认识新疆地区众多蛇绿混杂岩的形成构造环境提供了新思路。 相似文献
184.
Yu. B. Gladenkov 《Stratigraphy and Geological Correlation》2010,18(6):660-673
The problems of zonal stratigraphy of the early 21st century are discussed. The great advances achieved in recent years in using zones in geological practice are noted. At the same time, attention is drawn to the controversies existing in the interpretation of the concepts “biostratigraphic zone” and “chronozone,” in the methods of drawing the boundaries of such zones, and in the assessment of the spatial scale of zones and in the understanding of them as stratigraphic units. 相似文献
185.
186.
Zonal features of water acidification in small lakes of European Russia are analyzed. The conditions under which the process
can develop are evaluated. Studies of water chemistry variations and formulation of various criteria used to assess water
acidification made it possible to prove the development of the process in the humid part of the area under study, i.e., in
tundra, taiga, and forest regions. The leading natural and anthropogenic factors, whose combination governs the acidification
mechanism and secondary effects are discussed. The concentrations of some metals (Al, Zn, Pb, and others) are proved to increase
in waters with low pH, as well as at an increase in water color index. Critical loads of acid precipitation are evaluated
and the values of their exceedance in lakes in different natural-climatic zones. 相似文献
187.
M. deCastro M. Gómez-Gesteira I. Alvarez J.L.G. Gesteira 《Continental Shelf Research》2009,29(8):1053-1059
The warming trend observed during the last decades in the Bay of Biscay is put within the context of sea surface temperature (SST) changes observed in the area since 1854. Macroscopically, two consecutive warming–cooling cycles were detected during this period of time: cooling from 1867 to 1910; warming from 1910 to 1945; cooling from 1945 to 1974; and warming from 1974 to nowadays. Warming rates of 0.17 and 0.22 °C per decade were measured during the warming sub-periods and cooling rates of ?0.14 and ?0.10 °C per decade were measured during the cooling sub-periods. The present warming period is on the same order of magnitude although slightly more intense than the one observed from 1910 to 1945, which is consistent with previous analysis carried for the North Atlantic. Finally, the thermal amplitude defined as the difference between the maximum and minimum annual values has increased since 1974 at a rate of 0.06 °C per decade due to the different increasing rates of the maximum (0.26 °C per decade) and minimum (0.20 °C per decade) SSTs. 相似文献
188.
WANGHai-xia WANZhong-juan YUShao-peng LUOXin-zheng SUNGuang-you 《中国地理科学(英文版)》2004,14(2):179-185
Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rates and trends ofdesertification during the past 100 years in the Songnen Plain. According to the macroscopic analysis, we find that the eco-environment in the plain has reached to the threshold of catastrophic change since the 1950s. The Thorn Needle Catastrophic Model was used to determine and validate this conclusion. Human activities, including large-scale construction projects, such as huge dams and dikes, and excessive grazing were the primary factors contributing to regional eco-environmental catastrophe. And irrational reclamation of the wilderness also affected the eco-environmental change. The results reveal the complex human-land interactions. 相似文献
189.
I. M. Chertok 《Astronomy Reports》2006,50(1):68-78
Data obtained with the EIT UV telescope and LASCO coronagraph of the SOHO satellite are used to analyze large-scale solar disturbances associated with a series of major flares and coronal mass ejections that occurred in the late decline phase of cycle 23, on November 3–10, 2004, and gave rise to strong geomagnetic storms. Derotated fixed-base difference heliograms taken in the 195 Å coronal channel at 12-min intervals and in the various-temperature 171, 195, 284, and 304 Å channels at 6-h intervals indicate that these disturbances were global and homologous; i.e., they had similar characteristics and affected the same structures. Almost all of the nine events of this series included two recurrent systems of large-scale dimmings (regions of reduced intensity with lifetimes of 10–15 h): (a) transequatorial dimmings connecting a northern near-equatorial eruption center with a southern active region and (b) northern dimmings covering a large sector between two coronal holes. In this northern sector, coronal waves (brightenings propagated from the eruption center at speeds of several hundred km/s) were observed ahead of the expanding dimmings. The brightest, central part of the halo-type coronal mass ejection in each event corresponded to the northern dimming system. The properties of the dimmings and coronal waves and the relationship between them are discussed on the basis of the results obtained. We find that the eruption of large coronal mass ejections involves structures of the global solar magnetosphere with spatial scales far exceeding the sizes of active regions and normal activity complexes. 相似文献
190.
A problem of estimation of shock wave attenuation in an obstacle under an explosion of a high-energy material (explosive) charge on its surface is considered. An algorithm for its solution is proposed using the analytical and semiempirical dependences generally recognized in explosion physics. 相似文献