全文获取类型
| 收费全文 | 451篇 |
| 免费 | 482篇 |
| 国内免费 | 129篇 |
专业分类
| 测绘学 | 49篇 |
| 大气科学 | 6篇 |
| 地球物理 | 51篇 |
| 地质学 | 808篇 |
| 海洋学 | 90篇 |
| 综合类 | 24篇 |
| 自然地理 | 34篇 |
出版年
| 2023年 | 6篇 |
| 2022年 | 35篇 |
| 2021年 | 42篇 |
| 2020年 | 26篇 |
| 2019年 | 37篇 |
| 2018年 | 44篇 |
| 2017年 | 38篇 |
| 2016年 | 51篇 |
| 2015年 | 46篇 |
| 2014年 | 60篇 |
| 2013年 | 50篇 |
| 2012年 | 49篇 |
| 2011年 | 42篇 |
| 2010年 | 45篇 |
| 2009年 | 39篇 |
| 2008年 | 37篇 |
| 2007年 | 40篇 |
| 2006年 | 35篇 |
| 2005年 | 29篇 |
| 2004年 | 32篇 |
| 2003年 | 30篇 |
| 2002年 | 26篇 |
| 2001年 | 29篇 |
| 2000年 | 33篇 |
| 1999年 | 27篇 |
| 1998年 | 22篇 |
| 1997年 | 17篇 |
| 1996年 | 24篇 |
| 1995年 | 17篇 |
| 1994年 | 11篇 |
| 1993年 | 5篇 |
| 1992年 | 8篇 |
| 1991年 | 5篇 |
| 1990年 | 7篇 |
| 1989年 | 6篇 |
| 1988年 | 2篇 |
| 1987年 | 4篇 |
| 1986年 | 2篇 |
| 1985年 | 1篇 |
| 1984年 | 1篇 |
| 1983年 | 1篇 |
| 1972年 | 1篇 |
排序方式： 共有1062条查询结果，搜索用时 62 毫秒
1.
2.
重点分析了近几年我国水平定向钻进铺管钻机和施工市场的发展趋势,结合国外的水平定向钻进市场发展分析,总结了我国水平定向钻进技术与市场的发展态势。 相似文献
3.
4.
Li Yucheng 《海洋学报(英文版)》1996,15(2):261-272
Ｔｈｅｗａｖｅｔｒａｎｓｆｏｒｍａｔｉｏｎａｎｄｂｒｅａｋｉｎｇｐｈｅｎｏｍｅｎａｉｎｓｈａｌｌｏｗｗａｔｅｒ￥ＬｉＹｕｃｈｅｎｇ（１．ＤａｌｉａｎＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ，Ｄａｌｉａｎ１１６０２３，Ｃｈｉｎａ）Ａｂｓｔｒａｃｔ：... 相似文献
5.
6.
Yu Yuxiu Liu Shuxue Li Li Professor Dept. of Civil Engineering Dalian University of Technology Dalian
Research Assistant Dept. of Civil Engineering Dalian University of Technology Dalian 《中国海洋工程》1991,(3)
Multi-directional irregular waves are simulated on the basis of the given directional spectrum using a double summation model, a single direction per frequency model and a single summation model. Their results are compared. It is shown that the single direction per frequency model proposed in this paper can generate a realistic wave field. The effects of the model parameters on the simulated results are also studied in this paper and corresponding suggestions are given. 相似文献
7.
8.
Liu Shuxue Yu Yuxiu
Assistant Researcher State Key Laboratory of Coastal Offshore Engineering Dalian University of Technology 《中国海洋工程》1995,(1)
The directional spectrum is one of the basic characteristics of sea waves. The observations of directional spectrum of sea waves were successfully conducted at platform Bohai 8 during 1991 and 1992 using a wave gage array for the first time in China. Based on the field data, the directional spectrum which depends on the wave growth is given in this paper. Before observations, the effects of the type of gage array, the distance between the gages and the platform itself on the measured results and the precision of some methods for estimating the directional spectrum were investigated and compared with the methods of numerical simulations and model tests of multi-direcitonal irregular waves. This ensures the quality of the observations and estimations of the directional spectrum. 相似文献
9.
WANG Sheng''an LONG Xiaomin ZHANG Keben CHEN Junchang ZHANG Wenjing CAI Shuqun 《海洋学报(英文版)》2007,26(3):160-166
Multi-parameter hydrological gauge is an instrument developed by the South China Sea Institute of Oceanology,the Chinese Academy of Sciences to make simultaneous observation of current, wave, tide, water temperature and conductivity.By using the well-known "PUV method", the directional wave spectrum can be calculated and the dominant wave direction is then obtained.The comparison of the dominant wave directions derived from the measurements using both the multi-parameter hydrological gauge and the MARK Ⅱ "Wave-Rider" directional buoy shows that the dominant wave directions derived from the two kinds of measurements are in good agreement. 相似文献
10.
Ａｐｒｏｐｏｓｅｄｄｉｒｅｃｔｉｏｎａｌｆｕｎｃｔｉｏｎａｎｄｗｉｎｄ－ｗａｖｅｄｉｒｅｃｔｉｏｎａｌｓｐｅｃｔｒｕｍ￥ＷｅｎＳｈｅｎｇｃｈａｎｇ；ＷｕＫｅｊｉａｎ；ＧｕａｎＣｈａｎｇｌｏｎｇ；ＳｕｎＳｈｉｃａｉａｎｄＺｈａｎｇＤａｃｕｏ（Ｒｅｃｅｉ... 相似文献