全文获取类型
收费全文 | 45047篇 |
免费 | 6486篇 |
国内免费 | 8001篇 |
专业分类
测绘学 | 5911篇 |
大气科学 | 4812篇 |
地球物理 | 7127篇 |
地质学 | 20382篇 |
海洋学 | 4607篇 |
天文学 | 3402篇 |
综合类 | 3209篇 |
自然地理 | 10084篇 |
出版年
2024年 | 180篇 |
2023年 | 486篇 |
2022年 | 1574篇 |
2021年 | 1794篇 |
2020年 | 1684篇 |
2019年 | 2114篇 |
2018年 | 1508篇 |
2017年 | 1854篇 |
2016年 | 1865篇 |
2015年 | 2064篇 |
2014年 | 2502篇 |
2013年 | 2769篇 |
2012年 | 2683篇 |
2011年 | 2818篇 |
2010年 | 2333篇 |
2009年 | 2850篇 |
2008年 | 2843篇 |
2007年 | 2967篇 |
2006年 | 2892篇 |
2005年 | 2647篇 |
2004年 | 2406篇 |
2003年 | 2177篇 |
2002年 | 1878篇 |
2001年 | 1617篇 |
2000年 | 1602篇 |
1999年 | 1395篇 |
1998年 | 1196篇 |
1997年 | 896篇 |
1996年 | 739篇 |
1995年 | 598篇 |
1994年 | 585篇 |
1993年 | 490篇 |
1992年 | 362篇 |
1991年 | 301篇 |
1990年 | 204篇 |
1989年 | 163篇 |
1988年 | 142篇 |
1987年 | 84篇 |
1986年 | 51篇 |
1985年 | 56篇 |
1984年 | 32篇 |
1983年 | 24篇 |
1982年 | 16篇 |
1981年 | 13篇 |
1980年 | 15篇 |
1979年 | 6篇 |
1978年 | 16篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1954年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
151.
152.
Miguel Cerviño 《Astrophysics and Space Science》2003,284(2):897-900
Evolutionary synthesis models have been used to study the physical properties of unresolved populations in a wide range of
scenarios. Unfortunately, their self-consistency is difficult to test and there are some theoretical open questions without
an answer: (1) The change of the homology relations assumed in the computation of isochrones due to the effect of stellar
winds (or rotation) and the discontinuities in the stellar evolution are not considered. (2) There is no consensus about how
the isochrones must be integrated. (3) The discreteness of the stellar populations (that produce an intrinsic statistical
dispersion) usually are not taken into account, and model results are interpreted in a deterministic way instead of a statistical
one. The objective of this contribution is to present some inconsistencies in the computation and some cautions in the application
of the results of such codes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
153.
154.
155.
156.
157.
158.
尚永亮 《广东海洋大学学报》2003,23(2):27-29
古代荆湘之地域的特殊性使其成为朝廷贬官吏的首选之地和贬官的中转之地。在此 ,这些被贬官首创了大量关于贬谪的文学作品。其作品物色鲜明 ,楚地风情突出 ,具有近乎凝固化了的悲怨传统 ,早期逐臣、作品及谪地成为凝定的贬谪代码和符号 ,生成并积淀了深厚的人文精神。 相似文献
159.
WANGWei-wu ZHULi-zhong WANGRen-chao SHIYong-jung 《中国地理科学(英文版)》2003,13(1):39-47
Urban heat environmental quality(UHEQ) is affected by the interacting of weather condition and underlying surface framework of urban area .In the last two decades,many researchers from domestic and overseas have studied many problems at the aspect of urban heat environment such as urban heat islands ,urban air temperature and their rela-tion with urban land cover,city population,air pollution etc,In the recent years,Hangzhou,acting as a center city of Zhejiang Province in China,its urbanization quantum and quantity have both changed greatly,in particular ,representing as business affairs building,resident real property and all kins of specialty market having arisen in built-up zone,Based on Landsat TM images data in 1991 and 1999,urban underlying surface temperature value and Normalized Difference Vegetation Index (NDVI) were calculated using image interpreting and supervised classification technique by remote sensing software ERDAS image 8.4,The relation model between urban underlying surface temperature (UUST )and urban air temperature was setup according to the certain correlation patten .Reference to the relational standard of assessing human comfort and other meteorology data of Hangzhou City in summer,the spatial distribution characteristic and the spatial varia-tion degree of human comfort of heat environmental quality are estimated and mapped on a middle scale,that is ,in six districts of Hangzhou City .Then the paper reveals the main characteristic of spatial variation from 1991 to 1999.Lastly,the change mechanism is analyzed and discussed from the viewpoint of city planning,construction and environmental protec-tion. 相似文献
160.