全文获取类型
收费全文 | 2695篇 |
免费 | 412篇 |
国内免费 | 324篇 |
专业分类
化学 | 2244篇 |
晶体学 | 22篇 |
力学 | 136篇 |
综合类 | 33篇 |
数学 | 223篇 |
物理学 | 773篇 |
出版年
2024年 | 5篇 |
2023年 | 48篇 |
2022年 | 72篇 |
2021年 | 106篇 |
2020年 | 129篇 |
2019年 | 118篇 |
2018年 | 92篇 |
2017年 | 75篇 |
2016年 | 119篇 |
2015年 | 131篇 |
2014年 | 165篇 |
2013年 | 200篇 |
2012年 | 230篇 |
2011年 | 249篇 |
2010年 | 173篇 |
2009年 | 167篇 |
2008年 | 168篇 |
2007年 | 157篇 |
2006年 | 126篇 |
2005年 | 103篇 |
2004年 | 89篇 |
2003年 | 79篇 |
2002年 | 73篇 |
2001年 | 77篇 |
2000年 | 80篇 |
1999年 | 53篇 |
1998年 | 58篇 |
1997年 | 45篇 |
1996年 | 47篇 |
1995年 | 36篇 |
1994年 | 17篇 |
1993年 | 23篇 |
1992年 | 13篇 |
1991年 | 18篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1988年 | 12篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 8篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1966年 | 2篇 |
1931年 | 1篇 |
1924年 | 1篇 |
1884年 | 1篇 |
排序方式: 共有3431条查询结果,搜索用时 15 毫秒
1.
International Journal of Theoretical Physics - We consider the stationary state of a spin-orbit coupled (SOC) binary Bose-Einstein condensates with dipole-dipole interaction (DDI). Our results are... 相似文献
2.
Xinyu Zhang Linxuan Li Prof. Giuseppe Zanoni Xinyue Han Prof. Xihe Bi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(22):e202200280
The direct gem-difluoroalkenylation of X−H bonds represents the most straightforward approach to access heteroatomic gem-difluoroalkenes that, as the isostere of the carbonyl group, have great potency in drug discovery. However, the construction of tetrasubstituted heteroatomic gem-difluoroalkenes by this strategy is still an unsolved problem. Here, we report the first direct X−H bond gem-difluoroalkenylation of amines and alcohols with trifluoromethyl ketone N-triftosylhydrazones under silver (for (hetero)aryl hydrazones) or rhodium (for alkyl hydrazones), thereby providing a most powerful method for the synthesis of tetrasubstituted heteroatomic gem-difluoroalkenes. This method features a broad substrate scope, high product yield, excellent functional group tolerance, and operational simplicity (open air conditions). Moreover, the site-specific replacement of the carbonyl group with a gem-difluorovinyl ether bioisostere in drug Trimebutine and the post-modification of bioactive molecules demonstrates potential use in medicinal research. Finally, the reaction mechanism was investigated by combining experiments and DFT calculations, and disclosed that the key step of HF elimination occurred via five-membered ring transition state, and the difference in the electrophilicity of Ag- and Rh-carbenes as well as the multiple intermolecular interactions rendered the effectiveness of Rh catalyst selectively for alkyl hydrazones. 相似文献
3.
Czechoslovak Mathematical Journal - Comparing the bounded derived categories of an algebra and of the endomorphism algebra of a given support τ-tilting module, we find a relation between the... 相似文献
4.
Bi Dongxue Sverbil Pavel P. Voinov Yury P. Wu Mengyuan 《Journal of Russian Laser Research》2021,42(6):671-676
Journal of Russian Laser Research - We discuss the use of high-pressure high-temperature (HPHT) diamonds for the determination of trace amounts of various Raman active substances. The amount of the... 相似文献
5.
In this paper we consider iteration of single-plateau functions, an important class of continuous functions with infinitely many forts, and investigate changes of number and length of plateaux under iteration.We use the indices flatness, plateau limit and limit length to formulate those changes. Furthermore, we compute the flatness, plateau limit and limit length for all the nine types of single-plateau functions. 相似文献
6.
Zhong Yingying Li Qing-lan Lu Minglei Wang Tiantian Yang Huiyi He Qiyi Cui Xiping Li Xiangguang Zhao Suqing 《Mikrochimica acta》2020,187(12):1-11
Microchimica Acta - Testing gluten content in food, before it reaches the consumer, becomes a major challenge where cross-contamination during processing and transportation is a very common... 相似文献
7.
Wang Yingying Wang Donghui Shu Weiqing Sha Jingquan Zhang Haifeng 《Transition Metal Chemistry》2020,45(4):245-251
Transition Metal Chemistry - Two cubane-like complexes, namely [Ni4L4(HOEt)4] (1), [Co4L4(HOEt)4] (2) (H2L?=?(E)-2-((3-hydroxypropylimino)methyl)-6-methoxyphenol), were prepared under... 相似文献
8.
9.
10.
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