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701.
分解力是评定影象质量的重要指标。本文介绍利用改进后的国产9 w测微密度仪,测定航空软片静态分解力与曝光量的关系。以最大分解力所相应的曝光量作为确定航摄软片感光度的基准,以此为基础,确定航摄底片的最大密度(D_(max))、最小密度(D_(min))、影象反差(△D)和平均密度(D_R)本文对国产1022T、1022P、柯达2402、2412等航摄软片进行了研究,其试验结果可作为今后修改航摄规范的基础。 相似文献
702.
Wu Guoxiong 《大气科学进展》1988,5(2):141-148
Theoretical research and numerical modelling show that, although mountain torque owes its existence to the unevenness of the ground surface, its sign and intensity depend strongly upon the relative disposition be-tween mechanical and thermal forcing. The strong annual variations of mountain torque in the northern subtropics revealed by Yeh and Zhu (1958) are attributed to the different thermal features of Tibetan Plateau between winter and summer. 相似文献
704.
705.
This article, on the basis of the expert’s analyses and theories of the forecast of heavy-rain, summarizes a variety of the current instruments and methods of forecast and, according to the train of thought of the high-rank forecasters, distills their experiences in forecasting heavy-rain into an inference-tree of 106 junctures from which 101 rule-bases are derived. The logical calculation is automatically carried out with our introduced and developed PROLOG, one of the intelligent languagas by means of micro-computer. This process adopts the uncertain inferential method based on the theory of fuzzy sets, breaks through the limits of two-value logic and is characteristic of the thinking of human brain. 相似文献
706.
707.
吴萍 《沉积与特提斯地质》1988,8(Z1):14-28
一、引言自从Ginsburg(1955)及Logan等(1961,1964)研究了巴哈马、佛罗里达和西澳大利亚的现代藻叠层石以来,已经建立了用藻叠层石的形态和构造来解释现代或古代海洋沉积环境的基础。在我国,报道前寒武纪叠层石的文章较多,上古生代则不多见。作者自1980年以来对广东泥盆纪碳酸盐沉积中的藻叠层石做了一些研究,现根据所得资料进行报道。 相似文献
708.
Wu Qianghe 《《地质学报》英文版》1988,62(2):113-125
The Carboniferous in Guizhou may be divided into 3 lithostratigraphic regions, 2 series and 7 stages. TheLower Carboniferous is composed of 4 regional stages, 1 foraminifer assemblage, 4 fossil coral zones (with 9subzones) and 11 brachiopod assemblages; the Upper Carboniferous is divided into 3 regional. stages, 9fusulinid zones (with 2 subzones) and 4 ammonite zones. Based on the studies of foraminifers and conodonts.the base of the Carboniferous in Guizhou 1s placed at least near the top of the coral Cystophrentis zone. 相似文献
709.
在大连新港油罐区的建设中,发现了一种具有高孔隙性、高含水量、高塑性、中低压缩性的特殊土。作者对这种土及其母岩的矿物学、岩石学、地球化学、物理化学和工程特性进行了系统研究,揭示了该区红粘土及其工程特性的形成机理,该区红粘土乃是蒙脱石化的粗玄岩,在中温带气候区红土花作用的产物。 相似文献
710.
Types and distribution of silver ore deposits in China 总被引:2,自引:0,他引:2
Silver is generally recovered as a by- and co-product along with Au, Pb, Zn, Cu, Sb, Bi, Hg, Sn and W from polymetallic and
gold mines in China. Chinese silver deposits can be classified into five principal types according to host rocks. These types
and their host rocks are: (1) marine volcanic-sedimentary rocks hosting (la) massive sulfide Pb-Zn-(Cu)-Ag ores and (1b) stratiform
Ag-(Au) ores; (2) continental volcanic-sedimentary rocks containing (2a) various polymetallic-silver veins and/or stockworks,
and (2b) Ag-(Au) veins in pyroclastic rocks; (3) rocks affected by metasomatic processes including (3a) complex Sn-polymetallic-Ag
ores, (3b) Pb-Zn-(Cu)-Ag skarns, (3c) associated W-Ag quartz veins and/or skarns, and (3d) Ag-(Au) zones and veins in altered
carbonate rocks; (4) metamorphic-intrusive rocks, principally Ag-(Au) veins in sheared and brecciated metamorphic rocks; and
(5) sedimentary rocks including (5a) stratiform Pb-Zn-Ag ores in carbonate rocks, (5b) Ag-V mantos in black shales, and (5c)
Cu-(Ag) layers in red sandstones. A sixth grouping includes gossans. The tectonic settings, geological features, and temporal
and spatial distribution of these different types of silver occurrences indicate that silver mineralization reflects to a
great extent the evolution of tectonic environments in China throughout geological time. Type 1 is generally developed in
association with several fold belts from the Caledonian to Yanshanian orogens, while types 2, 3 and 4 correlate with rejuvenation
of the eastern China continent during the Mesozoic period. The three subgroups of type 5 are recognized in different stages
and various sedimentry and diagenetic environments during the development of paraplatforms and fold belts. Type 6 results
from recent weathering of existing sulfide ores or protores.
Editorial handling: DR 相似文献