全文获取类型
收费全文 | 3436篇 |
免费 | 563篇 |
国内免费 | 716篇 |
专业分类
测绘学 | 147篇 |
大气科学 | 680篇 |
地球物理 | 745篇 |
地质学 | 1871篇 |
海洋学 | 412篇 |
天文学 | 168篇 |
综合类 | 347篇 |
自然地理 | 345篇 |
出版年
2024年 | 15篇 |
2023年 | 70篇 |
2022年 | 167篇 |
2021年 | 188篇 |
2020年 | 127篇 |
2019年 | 132篇 |
2018年 | 177篇 |
2017年 | 162篇 |
2016年 | 191篇 |
2015年 | 156篇 |
2014年 | 217篇 |
2013年 | 183篇 |
2012年 | 167篇 |
2011年 | 184篇 |
2010年 | 201篇 |
2009年 | 192篇 |
2008年 | 166篇 |
2007年 | 156篇 |
2006年 | 106篇 |
2005年 | 91篇 |
2004年 | 58篇 |
2003年 | 88篇 |
2002年 | 84篇 |
2001年 | 93篇 |
2000年 | 105篇 |
1999年 | 157篇 |
1998年 | 115篇 |
1997年 | 143篇 |
1996年 | 129篇 |
1995年 | 116篇 |
1994年 | 105篇 |
1993年 | 84篇 |
1992年 | 76篇 |
1991年 | 62篇 |
1990年 | 51篇 |
1989年 | 44篇 |
1988年 | 40篇 |
1987年 | 13篇 |
1986年 | 26篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 16篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1969年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有4715条查询结果,搜索用时 9 毫秒
11.
12.
13.
14.
15.
本文针对国家重点牵引力动力实验室的机车车辆整车滚动振动试验台的特点,探讨了一套适合试验台安装和养护的精密测量方法,实践证明,这套方法能满足试验台安装所需的精度要求。 相似文献
16.
科学技术的发展,使测绘学的内涵发生了深刻的变化。要立足本省发展测缥,必须抓住机遇,扩大宣传,加速发展;同时要加速各项基础设施的建设,开拓市场;积极养素质的人才,以适应现代测 产业的需要。 相似文献
17.
Zhongli Tang 《中国地球化学学报》1984,3(2):102-114
So far three main genetic types of nickel deposit have been recognized in China: magmatic copper-nickel sulfide deposits, nickel deposits occurring in the crust of weathering, and sedimentary nickel deposits. On the basis of the geotectonic settings of intrusive bodies, their genetic types, and the way sulfides are concentrated, the copper-nickel sulfide deposits fall into two broad categories: deposits emplaced along paleolandmass edges and those in the mobile zones on the outside of paleolandmasses. They can further be divided into six sub-categories and then a variety of types. The magmatic copper-nickel sulfide deposits constitute one of the most important genetic types in China. Geological evidence shows that the individual ferruginous ultrabasic bodies intruding along paleolandmass edges are most favourable for Ni-mineralization. In the light of the paleo-structural analysis, the author has proposed three mechanisms with respect to the formation of Ni-bearing ultrabasic bodies. 相似文献
18.
The Austrian node of the Natural Resources Satellite Remote Sensing Cloud Service Platform was established in 2016 through a cooperation agreement between the Land Satellite Remote Sensing Application Center(LASAC),Ministry of Natural Resources of the Peoples Republic of China and the University of Vienna,Austria.Under this agreement panchromatic and multi-spectral data of the Chinese ZY-3 satellite are pushed to the server at the University of Vienna for use in education and research.So far,nearly 500 GB of data have been uploaded to the server.This technical note briefly introduces the ZY-3 system and illustrates the implementation of the agreement by the first China-Sat Workshop and several case studies.Some of them are already completed,others are still ongoing.They include a geometric accuracy validation of ZY-3 data,an animated visualization of image quick views on a spherical display to demonstrate the time series of the image coverage for Austria and Laos,and the use of ZY-3 data to study the spread of bark beetle in the province of Lower Austria.An accuracy study of DTMs from ZY-3 stereo data,as well as a land cover analysis and comparison of Austria with ZY-3 and other sensors are still ongoing. 相似文献
19.
20.
Ming Tang Zoe Falomir Christian Freksa Yehua Sheng Haiyang Lyu 《Transactions in GIS》2020,24(4):903-943
In geography, invariant aspects of sketches are essential to study because they reflect the human perception of real‐world places. A person's perception of a place can be expressed in sketches. In this article, we quantitatively and qualitatively analyzed the characteristics of single objects and characteristics among objects in sketches and the real world to find reliable invariants that can be used to establish references/correspondences between sketch and world in a matching process. These characteristics include category, shape, name, and relative size of each object. Moreover, quantity and spatial relationships—such as topological, ordering, and location relationships—among all objects are also analyzed to assess consistency between sketched and actual places. The approach presented in this study extracts the reliable invariants for query‐by‐sketch and prioritizes their relevance for a sketch‐map matching process. 相似文献