全文获取类型
收费全文 | 97022篇 |
免费 | 1259篇 |
国内免费 | 614篇 |
专业分类
测绘学 | 2000篇 |
大气科学 | 6222篇 |
地球物理 | 18650篇 |
地质学 | 34947篇 |
海洋学 | 8922篇 |
天文学 | 22642篇 |
综合类 | 249篇 |
自然地理 | 5263篇 |
出版年
2022年 | 710篇 |
2021年 | 1182篇 |
2020年 | 1237篇 |
2019年 | 1395篇 |
2018年 | 2873篇 |
2017年 | 2641篇 |
2016年 | 3053篇 |
2015年 | 1518篇 |
2014年 | 2951篇 |
2013年 | 5111篇 |
2012年 | 3246篇 |
2011年 | 4173篇 |
2010年 | 3813篇 |
2009年 | 4809篇 |
2008年 | 4197篇 |
2007年 | 4388篇 |
2006年 | 4012篇 |
2005年 | 2815篇 |
2004年 | 2750篇 |
2003年 | 2588篇 |
2002年 | 2604篇 |
2001年 | 2269篇 |
2000年 | 2180篇 |
1999年 | 1735篇 |
1998年 | 1776篇 |
1997年 | 1659篇 |
1996年 | 1420篇 |
1995年 | 1401篇 |
1994年 | 1214篇 |
1993年 | 1129篇 |
1992年 | 1074篇 |
1991年 | 1080篇 |
1990年 | 1061篇 |
1989年 | 944篇 |
1988年 | 855篇 |
1987年 | 1026篇 |
1986年 | 897篇 |
1985年 | 1093篇 |
1984年 | 1212篇 |
1983年 | 1179篇 |
1982年 | 1086篇 |
1981年 | 1008篇 |
1980年 | 912篇 |
1979年 | 887篇 |
1978年 | 845篇 |
1977年 | 728篇 |
1976年 | 716篇 |
1975年 | 716篇 |
1974年 | 686篇 |
1973年 | 774篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
I. Lerche 《Astrophysics and Space Science》1976,43(1):91-96
We demonstrate that the so-called force balance point, due to either magnetic fields (then known more specifically as the Alfvén point) or to co-rotation (Roche point), together with the concepts of flux and mass conservation, allows one to place interesting limits on both the size and angular velocity of astrophysical objects emitting by mass accretion. We give three numerical examples, which would seem to be of some astrophysical interest. 相似文献
122.
123.
124.
125.
126.
127.
I. R. Plimer 《Mineralogy and Petrology》2006,88(3-4):443-478
Summary The Palaeoproterozoic Broken Hill Pb–Zn–Ag stratiform orebody is intimately associated with manganoan garnet-bearing rocks.
On stratigraphic and chemical grounds it is argued that garnet-rich metasediments below, equivalent to and above massive sulphide
were hydrothermal precipitates. Other manganoan garnet rocks formed during pre-metamorphic hydrothermal alteration, syn-metamorphic
dehydration and reaction of manganese with prograde pelitic rocks, reaction between cataclastic manganese-bearing sulphide
rocks injected along axial planes, shears and faults and pelitic wall rocks and reaction between dolerite dykes and sulphide
rocks. 相似文献
128.
Origin of Geochemical Variability by Arc-Continent Collision in the Biru Area, Southern Sulawesi (Indonesia) 总被引:1,自引:0,他引:1
Analyses of igneous rocks from the Eocene calc-alkaline andMiocene potassic volcanic arc in southwest Sulawesi indicatethat magmas became more heterogeneous in their trace elementand PbSrNd isotopic signature following the collisionof the Buton microcontinent with the arc at 相似文献
129.
130.
Global assessment of the potential impacts of anthropogenically-induced climate change on vector-borne diseases suggests an increase in extent of the geographical areas susceptible to transmission of malarial Plasmodium parasites, dengue Flavivirus and Schistosoma worms. The transmission potential of the three associated vector-borne diseases studied is highly sensitive to climate changes on the periphery of the currently endemic areas and at higher altitudes within such areas. Our findings vis-à-vis the present endemic areas indicate that the increase in the epidemic potential of malaria and dengue transmission may be estimated at 12–27% and 31–47%, respectively, while in contrast, schistosomiasis transmission potential may be expected to exhibit a 11–17% decrease. 相似文献