全文获取类型
收费全文 | 24676篇 |
免费 | 657篇 |
国内免费 | 138篇 |
专业分类
化学 | 16826篇 |
晶体学 | 126篇 |
力学 | 584篇 |
数学 | 4404篇 |
物理学 | 3531篇 |
出版年
2022年 | 142篇 |
2021年 | 259篇 |
2020年 | 304篇 |
2019年 | 317篇 |
2018年 | 235篇 |
2017年 | 195篇 |
2016年 | 484篇 |
2015年 | 458篇 |
2014年 | 493篇 |
2013年 | 1308篇 |
2012年 | 1152篇 |
2011年 | 1439篇 |
2010年 | 736篇 |
2009年 | 714篇 |
2008年 | 1261篇 |
2007年 | 1292篇 |
2006年 | 1259篇 |
2005年 | 1220篇 |
2004年 | 1057篇 |
2003年 | 918篇 |
2002年 | 825篇 |
2001年 | 351篇 |
2000年 | 288篇 |
1999年 | 251篇 |
1998年 | 282篇 |
1997年 | 314篇 |
1996年 | 373篇 |
1995年 | 254篇 |
1994年 | 296篇 |
1993年 | 279篇 |
1992年 | 249篇 |
1991年 | 244篇 |
1990年 | 195篇 |
1989年 | 236篇 |
1988年 | 237篇 |
1987年 | 203篇 |
1986年 | 197篇 |
1985年 | 296篇 |
1984年 | 339篇 |
1983年 | 222篇 |
1982年 | 368篇 |
1981年 | 338篇 |
1980年 | 320篇 |
1979年 | 319篇 |
1978年 | 331篇 |
1977年 | 295篇 |
1976年 | 283篇 |
1975年 | 250篇 |
1974年 | 250篇 |
1973年 | 235篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Franck D'Agosto Marie‐Thrse Charreyre Christian Pichot Robert G. Gilbert 《Journal of polymer science. Part A, Polymer chemistry》2003,41(9):1188-1195
A method is described for synthesizing latex particles with anchored hairs by the grafting of hydrophilic chains, synthesized by reversible addition–fragmentation chain transfer, onto functionalized latex particles. These have the potential to bind biologically active species. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1188–1195, 2003 相似文献
52.
C.J. MeiningH.A. Nickel A.B. Dzyubenko A. PetrouM. Furis D.R. Yakovlev B.D. McCombe 《Solid State Communications》2003,127(12):821-827
Many body effects contribute significantly to the energy states of electron-hole pairs confined in quantum wells in the presence of excess electrons. We present results of optically detected resonance spectroscopy of the internal transitions of photo-excited electron-hole pairs in the presence of excess electrons for GaAs QWs and CdTe QWs. Compared to the case of isolated negatively charged excitons, excess electrons produce a large blue shift of the internal transitions in modulation-doped GaAs quantum wells (QWs) for filling factor <2, and similar effects are found in CdTe QWs. For filling factor >2 no internal transitions are observed. These measurements demonstrate the strong effects of electron-electron correlations on the internal transitions of charged excitons in these quasi-2D systems and the importance of magnetic translation invariance. In the presence of excess electrons, the observed internal transitions are those of a magnetoplasmon bound to a mobile valence band hole. 相似文献
53.
54.
Raymond G. McLenaghan Robert Milson Roman G. Smirnov 《Comptes Rendus Mathematique》2004,339(9):621-624
We show that the vector space of fixed valence Killing tensors on a space of constant curvature is naturally isomorphic to a certain highest weight, irreducible representation of the general linear group. The isomorphism is equivariant in the sense that the natural action of the isometry group corresponds to the restriction of the linear action to the appropriate subgroup. As an application, we deduce the Delong–Takeuchi–Thompson formula on the dimension of the vector space of Killing tensors from the classical Weyl dimension formula. To cite this article: R.G. McLenaghan et al., C. R. Acad. Sci. Paris, Ser. I 339 (2004). 相似文献
55.
Huimin Xie Biao Li Robert Geer Bai Xu James Castracane 《Optics and Lasers in Engineering》2003,40(3):163-177
A focused ion beam (FIB) Moiré method is proposed to measure the in-plane deformation of object in a micrometer scale. The FIB Moiré is generated by the interference between a prepared specimen grating and FIB raster scan lines. The principle of the FIB Moiré is described. The sensitivity and accuracy of deformation measurement are discussed in detail. Several specimen gratings with 0.14 and 0.20 μm spacing are used to generate FIB Moiré patterns. The FIB Moiré method is successfully used to measure the residual deformation in a micro-electro-mechanical system structure after removing the SiO2 sacrificial layer with a 5000 lines/mm grating. The results demonstrate the feasibility of this method. 相似文献
56.
Jacques Rouzaud MatthewD. Jones Robert Raja BrianF.G. Johnson John MeurigThomas MelindaJ. Duer 《Helvetica chimica acta》2003,86(5):1753-1759
A set of new, air‐stable, RhI‐based heterogeneous asymmetric hydrogenation catalysts have been synthesised, characterised, and tested. Individual members of this new family all exhibit good enantioselectivity. 相似文献
57.
Robert H. Crabtree 《Journal of organometallic chemistry》2004,689(24):4083-4091
The title topic is reviewed with emphasis on catalysis and on recent advances. Alkane σ complexes, Shilov chemistry and oxidative addition routes are covered. Attention is also given to σ bond metathesis, surface-bound organometallics and CH activation involving carbene complexes. Closely related reactions of non-alkane substrates such as the Murai reaction are also discussed. 相似文献
58.
59.
Cordula Grüttner Knut Müller Joachim Teller Fritz Westphal Allan Foreman Robert Ivkov 《Journal of magnetism and magnetic materials》2007
Bionized nanoferrite (BNF) particles with high specific power absorption rates were synthesized in the size range of 20–100 nm by high-pressure homogenization for targeted cancer therapy with alternating magnetic fields. Several strategies were used to conjugate antibodies to the BNF particles. These strategies were compared using an immunoassay to find optimal conditions to reach a high immunoreactivity of the final antibody–particle conjugate. 相似文献
60.