全文获取类型
收费全文 | 448302篇 |
免费 | 2842篇 |
国内免费 | 1008篇 |
专业分类
化学 | 213216篇 |
晶体学 | 7008篇 |
力学 | 24206篇 |
综合类 | 15篇 |
数学 | 63398篇 |
物理学 | 144309篇 |
出版年
2021年 | 3228篇 |
2020年 | 3409篇 |
2019年 | 4092篇 |
2018年 | 12000篇 |
2017年 | 12528篇 |
2016年 | 10717篇 |
2015年 | 4796篇 |
2014年 | 7271篇 |
2013年 | 16430篇 |
2012年 | 16148篇 |
2011年 | 24700篇 |
2010年 | 16774篇 |
2009年 | 16911篇 |
2008年 | 22293篇 |
2007年 | 25030篇 |
2006年 | 13305篇 |
2005年 | 16588篇 |
2004年 | 13478篇 |
2003年 | 12574篇 |
2002年 | 10962篇 |
2001年 | 11120篇 |
2000年 | 8633篇 |
1999年 | 6408篇 |
1998年 | 5341篇 |
1997年 | 5376篇 |
1996年 | 5106篇 |
1995年 | 4597篇 |
1994年 | 4540篇 |
1993年 | 4337篇 |
1992年 | 4901篇 |
1991年 | 5016篇 |
1990年 | 4851篇 |
1989年 | 4737篇 |
1988年 | 4717篇 |
1987年 | 4704篇 |
1986年 | 4436篇 |
1985年 | 5659篇 |
1984年 | 6023篇 |
1983年 | 4978篇 |
1982年 | 5096篇 |
1981年 | 5053篇 |
1980年 | 4734篇 |
1979年 | 5140篇 |
1978年 | 5233篇 |
1977年 | 5319篇 |
1976年 | 5422篇 |
1975年 | 5029篇 |
1974年 | 4911篇 |
1973年 | 5178篇 |
1972年 | 3617篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
N. I. Khamidov B. T. Kadyrov N. T. Ul'chenko A. Sh. Isamukhamedov A. I. Glushenkova 《Chemistry of Natural Compounds》1994,30(4):430-433
The phsicochemical indices and the fatty-acid and triacylglycerol compositions of cottonseed and palm oils, of cottonseed
oil hydrogenate, and of compositions based on them have been determined with the aid of IR and UV spectroscopies, GLC analysis,
and chemical transformations. The compositions and amounts of the main classes of lipids in the initial oils and the hydrogenate
have been studied. It has been found that in the process of hydrogenation the amount of oxygenated components falls.
The work was conducted with the financial support of the Uzbek Fund for Fundamental Investigations. 相似文献
33.
34.
Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 891475.
Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 679–680, September–October, 1994. 相似文献
35.
36.
37.
38.
39.
Summary Experiments and simulations prove that correlation chromatography can greatly reduce the disadvantage of a non-linear response of the chromatographic column. A factor that has been accepted as being an important source of error in correlation or multiplex chromatography, has been shown not to be. Separations affected, improve dramatically when correlation chromatography is used, and a substantial amount of correlation noise only arises when there is a large difference in separation between a conventional chromatogram and a correlogram.A model has been developed for simulating these nonlinearities. It is shown that, especially for correlation chromatography, the simulation results match the practical measurements very well. 相似文献
40.
Phase Relations and Sodium Ion Conductivity within the Quasi-binary System Na2SiF6/Na2AIF6 . The phase diagram of the Na2SiF6/Na3AlF6 system has been determined by means of x-ray powder diffraction, thermal analysis and conductivity measurements in the sub-solidus region. Na3AlF6 accomodates up to 73 mol.-% Na2SiF6 maintaining the crystal structure type. The sodium ion conductivity increases by about five orders of magnitude upon doping Na3AlF6 with Na2SiF6. 相似文献