全文获取类型
收费全文 | 6370篇 |
免费 | 215篇 |
国内免费 | 28篇 |
专业分类
化学 | 4056篇 |
晶体学 | 16篇 |
力学 | 314篇 |
数学 | 1102篇 |
物理学 | 1125篇 |
出版年
2023年 | 64篇 |
2022年 | 184篇 |
2021年 | 178篇 |
2020年 | 147篇 |
2019年 | 135篇 |
2018年 | 111篇 |
2017年 | 110篇 |
2016年 | 252篇 |
2015年 | 201篇 |
2014年 | 222篇 |
2013年 | 360篇 |
2012年 | 384篇 |
2011年 | 433篇 |
2010年 | 268篇 |
2009年 | 214篇 |
2008年 | 390篇 |
2007年 | 375篇 |
2006年 | 327篇 |
2005年 | 343篇 |
2004年 | 248篇 |
2003年 | 237篇 |
2002年 | 166篇 |
2001年 | 74篇 |
2000年 | 64篇 |
1999年 | 59篇 |
1998年 | 44篇 |
1997年 | 47篇 |
1996年 | 74篇 |
1995年 | 56篇 |
1994年 | 51篇 |
1993年 | 45篇 |
1992年 | 31篇 |
1991年 | 37篇 |
1990年 | 38篇 |
1989年 | 37篇 |
1988年 | 36篇 |
1987年 | 43篇 |
1986年 | 23篇 |
1985年 | 47篇 |
1984年 | 51篇 |
1983年 | 27篇 |
1982年 | 29篇 |
1981年 | 33篇 |
1980年 | 31篇 |
1979年 | 20篇 |
1978年 | 25篇 |
1977年 | 33篇 |
1976年 | 12篇 |
1975年 | 21篇 |
1974年 | 14篇 |
排序方式: 共有6613条查询结果,搜索用时 15 毫秒
1.
Meccanica - The static limit analysis of axially symmetric masonry domes subject to pseudo-static seismic forces is addressed. The stress state in the dome is represented by the shell stress... 相似文献
2.
Journal of Optimization Theory and Applications - Pollution management models of Shallow Lake type identify a well-known class of infinite horizon optimal control problems, characterized by the... 相似文献
3.
4.
Numerical Algorithms - We introduce a modulus-based formulation for vertical linear complementarity problems (VLCPs) with an arbitrary number ? of matrices. This formulation can be used to... 相似文献
5.
Francesco Segatta David M. Rogers Naomi T. Dyer Ellen E. Guest Zhuo Li Hainam Do Artur Nenov Marco Garavelli Jonathan D. Hirst 《Molecules (Basel, Switzerland)》2021,26(2)
A fully quantitative theory of the relationship between protein conformation and optical spectroscopy would facilitate deeper insights into biophysical and simulation studies of protein dynamics and folding. In contrast to intense bands in the far-ultraviolet, near-UV bands are much weaker and have been challenging to compute theoretically. We report some advances in the accuracy of calculations in the near-UV, which were realised through the consideration of the vibrational structure of the electronic transitions of aromatic side chains. 相似文献
6.
Vito Gigante Laura Aliotta Maria Beatrice Coltelli Patrizia Cinelli Luigi Botta Francesco Paolo La Mantia Andrea Lazzeri 《Journal of polymer science. Part A, Polymer chemistry》2020,58(23):3264-3282
The development of biodegradable materials for tailored applications, particularly in the field of polymeric films and sheets, is a challenging technological goal as well as a contribution to help protect the environment. Poly(lactic) acid (PLA) is a promising substitute for several oil-based polymers; however, to overcome its thermal and mechanical drawbacks, researchers have developed solutions such as blending PLA with polybutylene adipate terephthalate (PBAT), which is capable of increasing the ductility of the final material. In this study, PLA/PBAT binary blends, with minimum possible content of nonrenewable materials, were examined from processing, thermal, morphological, and rheological perspective. An optimized PLA/PBAT ratio was chosen as the polymeric basis to obtain a biodegradable formulation by adding a biobased plasticizer and appropriate fillers to produce a micrometer film with tailored flexibility and tear resistance. The processing technology involved flat-die extrusion, followed by calendering. The tearing resistance of the produced film was investigated, and the results were compared with literature data. A study on the essential work of fracture was implemented to explore the mode III out-of-plane fracture resistance starting from a trouser tear test. 相似文献
7.
8.
The effect of hydrophilic ionic liquids (ILs) on the activity of chloroperoxidase (CPO) was checked through kinetic and stereochemical studies. The possibility to employ this enzyme in synthesis has been demonstrated investigating the chemo- and stereoselectivity of oxidation of phenyl methylsulfide in several citrate buffer-IL mixtures. 相似文献
9.
10.
In this paper we define trace functionals on the algebra of pseudo-differential operators with cone-shaped exits to infinity. Furthermore, we improve the Weyl formula on the asymptotic distribution of eigenvalues and make use of it in order to establish inclusion relations between the interpolation normed ideals of compact operators in L
2(R
n
) and the above operator classes. 相似文献