全文获取类型
收费全文 | 93571篇 |
免费 | 2928篇 |
国内免费 | 3632篇 |
专业分类
化学 | 37506篇 |
晶体学 | 1062篇 |
力学 | 7335篇 |
综合类 | 239篇 |
数学 | 33504篇 |
物理学 | 20485篇 |
出版年
2024年 | 41篇 |
2023年 | 283篇 |
2022年 | 576篇 |
2021年 | 599篇 |
2020年 | 648篇 |
2019年 | 691篇 |
2018年 | 10906篇 |
2017年 | 10767篇 |
2016年 | 6781篇 |
2015年 | 1692篇 |
2014年 | 1318篇 |
2013年 | 1674篇 |
2012年 | 5214篇 |
2011年 | 11970篇 |
2010年 | 6791篇 |
2009年 | 7123篇 |
2008年 | 7829篇 |
2007年 | 9840篇 |
2006年 | 1230篇 |
2005年 | 2133篇 |
2004年 | 2195篇 |
2003年 | 2499篇 |
2002年 | 1542篇 |
2001年 | 704篇 |
2000年 | 670篇 |
1999年 | 476篇 |
1998年 | 411篇 |
1997年 | 322篇 |
1996年 | 386篇 |
1995年 | 292篇 |
1994年 | 225篇 |
1993年 | 209篇 |
1992年 | 131篇 |
1991年 | 148篇 |
1990年 | 126篇 |
1989年 | 97篇 |
1988年 | 106篇 |
1987年 | 78篇 |
1986年 | 89篇 |
1985年 | 73篇 |
1984年 | 63篇 |
1983年 | 53篇 |
1982年 | 49篇 |
1981年 | 44篇 |
1980年 | 52篇 |
1979年 | 48篇 |
1914年 | 45篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
11.
12.
Sarah Peluse 《Israel Journal of Mathematics》2018,227(1):379-396
We prove that the group of diffeomorphisms of the interval [0, 1] contains surface groups whose action on (0, 1) has no global fix point and such that only countably many points of the interval (0, 1) have non-trivial stabiliser. 相似文献
13.
14.
JPC – Journal of Planar Chromatography – Modern TLC - A new high-performance thin-layer chromatographic (HPTLC) method has been developed for the simultaneous estimation of... 相似文献
15.
Yao Yuan Chen Ying Chen Jianyong Gong Yulie 《Journal of Thermal Analysis and Calorimetry》2021,144(6):2357-2367
Journal of Thermal Analysis and Calorimetry - Based on innovative design, a liquid–vapor separation plate condenser with excellent heat transfer performance is invented. It takes less time to... 相似文献
16.
Natural products with a variety of pharmacological effects are important sources for commercial drugs, and it is very crucial to develop effective techniques to selectively extract and isolate bioactive natural components from the plants against the background of sustainable development. Ionic liquids (ILs) are a kind of designable material with unique physicochemical properties, including good thermal stability, negligible vapor pressure, good solvation ability, etc. ILs have already been used in pharmaceuticals for extraction, purification, drug delivery, etc. It has been reported that multi-interactions, like hydrogen bonding, hydrophobic interactions, play important roles in the extraction of bioactive components from the plants. In this review, recent progress in the understanding of scientific essence of hydrogen bonding, the special interaction, in ILs was summarized. The extraction of various natural products, one important area in pharmaceutical, by conventional and functional ILs as well as the specific roles of multi-interactions in this process were also reviewed. Moreover, problems existing in bioactive compound extraction by ILs and the future developing trends of this area are given, which might be helpful for scientists, especially beginners, in this field. 相似文献
17.
18.
19.
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
20.
S. V. Panin I. V. Vlasov V. P. Sergeev B. B. Ovechkin P. O. Marushchak Sunder Ramasubbu P. S. Lyubutin V. V. Titkov 《Physical Mesomechanics》2015,18(3):261-272
The structure and properties of 12Cr1MoV steel irradiated with a zirconium ion beam were studied by optical microscopy, scanning electron microscopy, and micro- and nanoindentation. It is shown that the modification covers the entire cross-section of the irradiated specimens to a depth of 1 mm. The data on irradiation-induced structural changes are used to interpret the changes in mechanical properties of the irradiated specimens under static and cyclic loading. Particular attention is given to analysis of strain estimation by the digital image correlation method. 相似文献