全文获取类型
收费全文 | 7143篇 |
免费 | 1395篇 |
国内免费 | 1827篇 |
专业分类
测绘学 | 577篇 |
大气科学 | 1376篇 |
地球物理 | 1584篇 |
地质学 | 3710篇 |
海洋学 | 1054篇 |
天文学 | 263篇 |
综合类 | 695篇 |
自然地理 | 1106篇 |
出版年
2024年 | 36篇 |
2023年 | 118篇 |
2022年 | 353篇 |
2021年 | 398篇 |
2020年 | 343篇 |
2019年 | 388篇 |
2018年 | 411篇 |
2017年 | 374篇 |
2016年 | 441篇 |
2015年 | 393篇 |
2014年 | 460篇 |
2013年 | 458篇 |
2012年 | 454篇 |
2011年 | 490篇 |
2010年 | 504篇 |
2009年 | 483篇 |
2008年 | 458篇 |
2007年 | 410篇 |
2006年 | 323篇 |
2005年 | 277篇 |
2004年 | 224篇 |
2003年 | 196篇 |
2002年 | 222篇 |
2001年 | 204篇 |
2000年 | 206篇 |
1999年 | 269篇 |
1998年 | 203篇 |
1997年 | 220篇 |
1996年 | 165篇 |
1995年 | 164篇 |
1994年 | 116篇 |
1993年 | 132篇 |
1992年 | 106篇 |
1991年 | 76篇 |
1990年 | 40篇 |
1989年 | 51篇 |
1988年 | 43篇 |
1987年 | 38篇 |
1986年 | 34篇 |
1985年 | 15篇 |
1984年 | 16篇 |
1983年 | 15篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1975年 | 1篇 |
1958年 | 3篇 |
1954年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 734 毫秒
961.
Wu Chaoyuan Li Jiajun Xia Enzhan Peng Zhuosheng Tan Shuzhi Li Jun Wen Zongcun Huang Xiaohang Cai Zulin Chen Guojun 《中国海洋湖沼学报》1989,7(4):327-334
A 2-year study onKappaphycus alvarezii (Doty) Doty introduced to Hainan Island from the Philippines in 1985 showed promising results. The average daily growth in
weight reached 10% at a favourable temperature of about 26°C. Experimental results showed that timely cutting of the plant
was an effective way to obtain new cuttings for cultivation and accelerate growth. New cuttings 0.05 kg in weight are suggested
to be used as “seeds” and the old plant should be harvested. At present, artificial cultivation with a type of underwater
raft applicable in places where there is strong wind will expand cultivation to more regions in Hainan Province.
This paper was originally published in Chinese inOceanologia et Limnologia Sinica
19(5): 410–418, 1988. The plant under discussion wasEucheuma alvarezii Doty which was previously calledE. striatum in the article, and which now becomesKappaphycus alvarezii (Doty) Doty. To the original title, “in China” was added. Only the essence of the original article was presented. 相似文献
962.
963.
964.
XPer的新发射相:光谱与红外观测 总被引:1,自引:0,他引:1
XPer的新发射相:光谱与红外观测杭恒荣,夏剑萍中国科学院紫金山天文台,南京210008中国科学院光学天文联合实验室关键词Be星/X射线双星,发射线,JHK测光1引言XPer是一颗Be/X射线双星(4U0352+30)的光学对应体[1-3],中子星的... 相似文献
965.
THE RESEARCH ON THE DISTRIBUTION AND FORMS OF HEAVY METALS IN THE XIANGJIANG RIVER SEDIMENTS 总被引:1,自引:0,他引:1
In this paper, the contents and various forms of Cd, Cu, Zn and Pb in the sediments of the Xiangjiang River have been investigated. The presentation of this paper focuses on the various forms and characteristics of the heavy metals in the column sediments at Xiawan Port of Zhuzhou, which has been severely polluted by a metallurgical plant.The forms of the heavy metals discussed in this paper are: The concentration of the exchangeable forms of Cd, Cu, Zn and Pb, in the forms of carbonates and Fe/ Mn oxide in water, the combination of Cu with organic matter and form, and the proportion of the residue form at each section have been studied. 相似文献
966.
QU Jianjun YAN Muhong DONG Guangrong ZHANG Hongfa ZU Ruiping TUO Wanquan ZHAO Aiguo XlAO Zhenghua LI Fang & YANG Bao Key Laboratory of Desert Desertification Cold Arid Regions Environmental Engineering Research Institute Shapotou Desert Research Experiment Station Chinese Academy of Sciences Lanzhou China 《中国科学D辑(英文版)》2004,47(6):529-539
~~Wind tunnel simulation experiment and investigation on the electrification of sandstorms~~ 相似文献
967.
On the evolution and histology of some Cambrian protoconodonts,paraconodonts and primitive euconodonts 总被引:4,自引:0,他引:4
DONG Xiping Department of Geology Peking University Beijing China Laboratory of Palaeobiology & Stratigraphy Nanjing Institute of Ge-ology Palaeontology Chinese Academy of Sciences Nanjing China 《中国科学D辑(英文版)》2004,47(7):577-584
Although the history of Cambrian conodont study goes back to a century ago, it was not until 1959 that the systematic study of Cambrian conodonts was initi-ated[1]. During the last 44 years Cambrian conodonts have been well documented from all continents but Africa. However, the morphological evolution of para- conodonts and protoconodonts have been subjected to less study than the primitive euconodonts in the inter-val across the Cambrian-Ordovician boundary. Miller (1984) proposed a Weste… 相似文献
968.
DONGSheng GANBuhong HAOXiaoli 《中国海洋大学学报(英文版)》2004,3(1):111-114
1 Introduction InChina ,coastalcitiesaremostlyregionaleconomicdevelopmentcenters.Becauseoftheirspecialgeogra phiclocations ,typhoonsandassociatedstormsurgescauseheavylossesoflivesandproperties.In 1 992 Qing daowasfloodedduetothecoincidenceoftheastrono m… 相似文献
969.
970.