全文获取类型
收费全文 | 201817篇 |
免费 | 3490篇 |
国内免费 | 1560篇 |
专业分类
化学 | 112967篇 |
晶体学 | 3407篇 |
力学 | 8238篇 |
综合类 | 57篇 |
数学 | 19451篇 |
物理学 | 62747篇 |
出版年
2018年 | 1500篇 |
2016年 | 2676篇 |
2015年 | 2074篇 |
2014年 | 2912篇 |
2013年 | 8397篇 |
2012年 | 5967篇 |
2011年 | 7355篇 |
2010年 | 4903篇 |
2009年 | 4788篇 |
2008年 | 6465篇 |
2007年 | 6527篇 |
2006年 | 6294篇 |
2005年 | 5750篇 |
2004年 | 5251篇 |
2003年 | 4643篇 |
2002年 | 4515篇 |
2001年 | 5949篇 |
2000年 | 4503篇 |
1999年 | 3690篇 |
1998年 | 2862篇 |
1997年 | 2870篇 |
1996年 | 2832篇 |
1995年 | 2626篇 |
1994年 | 2480篇 |
1993年 | 2340篇 |
1992年 | 2836篇 |
1991年 | 2717篇 |
1990年 | 2675篇 |
1989年 | 2679篇 |
1988年 | 2604篇 |
1987年 | 2606篇 |
1986年 | 2428篇 |
1985年 | 3279篇 |
1984年 | 3294篇 |
1983年 | 2725篇 |
1982年 | 2913篇 |
1981年 | 2853篇 |
1980年 | 2754篇 |
1979年 | 2896篇 |
1978年 | 3139篇 |
1977年 | 2960篇 |
1976年 | 2895篇 |
1975年 | 2754篇 |
1974年 | 2702篇 |
1973年 | 2716篇 |
1972年 | 1759篇 |
1968年 | 1925篇 |
1967年 | 2126篇 |
1966年 | 1920篇 |
1965年 | 1497篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
46.
This study is concerned with a new,explicit approach by means of which forms of the large strain elastic potential for multiaxial rubberlike elasticity may be obtained based on data for a single deformation mode.As a departure from usual studies,here for the first time errors may be estimated and rendered minimal for all possible deformation modes and,furthermore,failure behavior may be incorporated.Numerical examples presented are in accurate agreement with Treloar's well-known data. 相似文献
47.
Yin Pengpeng Liu Chang Wang Ying Guan Lei Chen Xian Xiong Xuejia Jin Hongzhe 《Russian Journal of General Chemistry》2021,91(5):897-903
Russian Journal of General Chemistry - A dinuclear Tb complex, Tb2(H2L)3(phen)2 (1), and two similar N-donor coordination complexes, Fe(phen)3·HL (2), Fe(bipy)3·HL·5H2O (3) (Na2H2L =... 相似文献
48.
Simultaneous quantitative determination of 20 active components in the traditional Chinese medicine formula Zhi‐Zi‐Da‐Huang decoction by liquid chromatography coupled with mass spectrometry: application to study the chemical composition variations in different combinations 下载免费PDF全文
Zheng Tang Ran Yin Kaishun Bi Heyun Zhu Fei Han Kelin Chen Fenrong Wang 《Biomedical chromatography : BMC》2015,29(9):1406-1414
49.
Hui Li Jian Liu Juan Zhao Huiting He Dr. Dabo Jiang Prof. Steven Robert Kirk Prof. Qiong Xu Dr. Xianxiang Liu Prof. Dulin Yin 《ChemistryOpen》2021,10(4):477-485
A series of tetraimidazolium salts with different anions was prepared and applied in the isomerization of β-pinene oxide. After examining the activity of different catalysts, a remarkable enhancement of the selectivity of perillyl alcohol (47 %) was obtained over [PEimi][HNO3]4 under mild reaction conditions and using DMSO as the solvent. Furthermore, noncovalent interactions between solvent molecules and the catalyst were found by FT-IR spectroscopy and confirmed by computational chemistry. The homogeneous catalyst showed excellent stability and was reused up to six times without significant loss. 相似文献
50.
Sergio Ayala‐Mar Javier Donoso‐Quezada Roberto C. Gallo‐Villanueva Victor H. Perez‐Gonzalez Jos Gonzlez‐Valdez 《Electrophoresis》2019,40(23-24):3036-3049
Exosomes are nanovesicles secreted by most cellular types that carry important biochemical compounds throughout the body with different purposes, playing a preponderant role in cellular communication. Because of their structure, physicochemical properties and stability, recent studies are focusing in their use as nanocarriers for different therapeutic compounds for the treatment of different diseases ranging from cancer to Parkinson's disease. However, current bioseparation protocols and methodologies are selected based on the final exosome application or intended use and present both advantages and disadvantages when compared among them. In this context, this review aims to present the most important technologies available for exosome isolation while discussing their advantages and disadvantages and the possibilities of being combined with other strategies. This is critical since the development of novel exosome‐based therapeutic strategies will be constrained to the effectiveness and yield of the selected downstream purification methodologies for which a thorough understanding of the available technological resources is needed. 相似文献