全文获取类型
收费全文 | 78282篇 |
免费 | 26215篇 |
国内免费 | 53314篇 |
专业分类
测绘学 | 11912篇 |
大气科学 | 25104篇 |
地球物理 | 19663篇 |
地质学 | 60176篇 |
海洋学 | 22800篇 |
天文学 | 1272篇 |
综合类 | 7532篇 |
自然地理 | 9352篇 |
出版年
2024年 | 760篇 |
2023年 | 1925篇 |
2022年 | 3758篇 |
2021年 | 4642篇 |
2020年 | 4760篇 |
2019年 | 7658篇 |
2018年 | 7351篇 |
2017年 | 7020篇 |
2016年 | 7174篇 |
2015年 | 7360篇 |
2014年 | 6682篇 |
2013年 | 7889篇 |
2012年 | 8224篇 |
2011年 | 8055篇 |
2010年 | 8060篇 |
2009年 | 7118篇 |
2008年 | 6601篇 |
2007年 | 6463篇 |
2006年 | 5899篇 |
2005年 | 5123篇 |
2004年 | 4679篇 |
2003年 | 3807篇 |
2002年 | 3652篇 |
2001年 | 3282篇 |
2000年 | 2717篇 |
1999年 | 2001篇 |
1998年 | 1783篇 |
1997年 | 1848篇 |
1996年 | 1426篇 |
1995年 | 1352篇 |
1994年 | 1203篇 |
1993年 | 1177篇 |
1992年 | 1010篇 |
1991年 | 746篇 |
1990年 | 729篇 |
1989年 | 592篇 |
1988年 | 521篇 |
1987年 | 420篇 |
1986年 | 351篇 |
1985年 | 268篇 |
1984年 | 298篇 |
1983年 | 176篇 |
1982年 | 227篇 |
1981年 | 164篇 |
1980年 | 112篇 |
1979年 | 136篇 |
1978年 | 54篇 |
1977年 | 48篇 |
1971年 | 53篇 |
1970年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
881.
岩质边坡稳定性分析的探讨 总被引:2,自引:0,他引:2
通过最大剪应力等值线来确定边坡的滑动面,并与其结构面抗剪强度相比较,给出了确定边坡的稳定系数的方法。 相似文献
882.
883.
884.
885.
886.
887.
888.
889.
ZhangBingshan TangLiangjie JinZhijun DaiJunsheng ZhangMingli ZhangBingshan 《中国地质大学学报(英文版)》2003,14(1):65-72
The purpose of this paper is to analyze the regional fault systems of Qaidam basin and ad-jacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault sys-tans occurred in the Qaidam and adjacent nment.qin belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunhm Mountain fault system;(3)Altun strike-slip fault system; (4) Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accmnulation belt. 相似文献
890.
Development of Geological Data Warehouse 总被引:2,自引:0,他引:2
LiZhenhua HuGuangdao ZhangZhenfei 《中国地质大学学报(英文版)》2003,14(3):261-264
Data warehouse (DW), a new technology invented in 1990s, is more useful for integrating and analyzing massive data than traditional database. Its application in geology field can be divided into 3 phrases: 1992-1996, commercial data warehouse (CDW) appeared; 1996-1999, geological data warehouse (GDW) appeared and the geologists or geographers realized the importance of DW and began the studies on it, but the practical DW still followed the framework of DB; 2000 to present, geological data warehouse grows, and the theory of geo-spatial data warehouse (GSDW) has been developed but the research in geological area is still deficient except that in geography. Although some developments of GDW have been made, its core still follows the CDW-organizing data by time and brings about 3 problems: difficult to integrate the geological data, for the data feature more space than time; hard to store the massive data in fifferent levels due to the same reason; hardly support the spatial analysis if the data are organized by time as CDW does. So the GDW should be redesigned by organizing data by scale in order to store mass data in different levels and synthesize the data in different granularities, and choosing space control points to replace the former time control points so as to integrate different types of data by the method of storing one type data as one layer and then to superpose the layers. In addition, data cube, a wide used technology in CDW, will be no use in GDW, for the causality among the geological data is not so obvious as commercial data, as the data are the mixed result of many complex rules, and their analysis needs the special geological methods and software; on the other hand, data cube for mass and complex geo-data will devour too much store space to be practical. On this point, the main purpose of GDW may be fit for data integration unlike CDW for data analysis. 相似文献