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981.
本文提出了多搜索变量的目标函数直接优化法。该方法不涉及目标函数的导数计算,通用性强;同时该方法可控制搜索变量在值域内取值,这在一定程度上保证了解的可靠性。用此方法,本文分析了1984年2月18日太阳边缘环珥的一些Hα谱线,结果表明,本文方法具有收敛半径大,精度高的特点。 相似文献
982.
Journal of Geographical Sciences - Eco-environmental sustainability is the basis for sustainable development in ecologically fragile areas. Land consolidation plays an important role in... 相似文献
983.
Song Yao Hao-Tong Zhang Hai-Long Yuan Yong-Heng Zhao Yi-Qiao Dong Zhong-Rui Bai Li-Cai Deng Ya-Juan Lei 《中国天文和天体物理学报》2013,(10):1255-1268
Using a sky brightness monitor at the Xinglong station of National Astronomical Observatories,Chinese Academy of Sciences,we collected data from22 dark clear nights and 90 moon nights.We first measured the sky brightness variation with time for dark nights and found a clear correlation between sky brightness and human activity.Then with a modified sky brightness model of moon nights and data from these nights,we derived the typical value for several important parameters in the model.With these results,we calculated the sky brightness distribution under a given moon condition for the Xinglong station.Furthermore,we simulated the sky brightness distribution of a moon night for a telescope with a 5 field of view(such as LAMOST).These simulations will be helpful for determining the limiting magnitude and exposure time,as well as planning the survey for LAMOST during moon nights. 相似文献
984.
China Ocean Engineering - Flow-induced vibration energy harvesting devices typically use an elastically supported body immersed in an oncoming flow to convert the sea and river current’s... 相似文献
985.
新疆及邻区地震构造图简介 总被引:1,自引:0,他引:1
This paper briefly introduces the Seismotectonic Map of Xinjiang and its neighborhood in the scale of 1∶2500000.The map is amended,supplemented and expanded based of the newly compiled Seismotectonic Map of Xinjiang in scale 1∶1000000.The base map of this seismotectonic map is the geologic map of western China and its neighborhood compiled by Li Tingdong.The abundant new materials from related research,referential literatures and the analyses on remote sensing data were used in the compiling work.A database and relevant documents are built for nearly 300 active faults and 150 active folds.The basic information of the major active faults,especially those near the border areas in this map are introduced in this paper. 相似文献
986.
987.
富县地区延长组主要发育三角洲和湖泊沉积体系,其中分流河道和水下分流河道骨架砂体呈北东-南西向条带状展布,纵向上连续性好,是主要储集体。岩性主要为灰色-灰绿色细-中粒岩屑长石砂岩和长石砂岩,填隙物主要是胶结物,以方解石、绿泥石膜为主。主要受沉积和成岩作用两个因素控制,储层物性较差,纵向上和横向上非均质性均较强。层内非均质性主要影响因素为垂向上粒度分布的韵律性、层理构造、层内夹层和层内裂缝等,层内渗透率非均质参数表现为中等-强的非均质性;分层系数和砂岩密度长8、长6、长3和长2油层组较大,长7和长4+5油层组较小;层间渗透率非均质参数长8、长6及长3较大,为强非均质性,长7和长2较小,非均质性相对较弱,为中等非均质性。 相似文献
988.
989.
Although the calculation of radiative transfer in the middle-shortwave infrared band is important in the field of optical remote sensing, studies in this area of research are rare in China. Both solar reflection and atmospheric emission should be considered when calculating radiative transfer in the middle-shortwave infrared band. This paper presents a new radiative transfer model based on the doubling and adding method. The new model uses approximate calculations of direct solar reflection,multiple scattering, and thermal emissions for a finitely thin atmospheric layer and considers both the solar and thermal sources of radiation. To verify its accuracy, the calculation results produced by the model for four typical scenarios(single layer at night,multi-layer aerosols, double-layer with ice and water clouds, and multi-layer with clouds and aerosols) were compared with those of the DISORT model. With the exception of a few channels, the absolute deviation between the two models was less than2×10~(-6) K. For the same calculation, the computation speed of the new model was approximately two to three times faster than that of the DISORT model. Sensitivity studies were performed to evaluate the error resulting from using simplified calculation methods in the new model. The results obtained in this study indicated that atmospheric thermal emission made a significant contribution to the measured radiance in the strong-absorption band(2230–2400 cm~(-1)), whereas solar radiation could be neglected in this region. However, neglecting solar radiation in the window region(2400–2580 cm~(-1)) introduced error on the order of dozens of K. Employing the average-layer temperature method simplified the calculation of thermal radiation but caused a larger error in the strong-absorption band than in the window region. In the doubling and adding method, the calculation error decreased as the value used for minimum optical thickness decreased. Under the condition of satisfying the requirement of calculation precision, we can consider using the layer-average temperature radiation method and selecting a relative larger minimum optical thickness value to improve the calculation efficiency. The new radiative calculation model proposed herein can be used in the simulation, inversion, and assimilation of middle-shortwave infrared measurements by hyper-spectral satellite instruments. 相似文献
990.
甲烷氧化与氨氧化微生物及其耦合功能 总被引:2,自引:0,他引:2
甲烷氧化与氨氧化过程分别对控制温室气体甲烷和氧化亚氮方面有着特殊作用,土壤及湿地等环境中的甲烷氧化菌和氨氧化菌在生态系统碳、氮生物循环中扮演着重要的角色。论述了甲烷氧化与氨氧化过程的微生物学机制,甲烷氧化菌和氨氧化菌的群落结构变化,分析了甲烷氧化菌和氨氧化菌在碳、氮循环以及它们在控制重要温室气体排放中的环境功能,阐述了甲烷氧化菌和氨氧化菌的关联作用机制。以期深入揭示甲烷氧化菌与氨氧化菌的空间分异与耦合机制,为深入探讨这类微生物的生态机制和环境功能提供科学线索。 相似文献