全文获取类型
收费全文 | 7179篇 |
免费 | 266篇 |
国内免费 | 39篇 |
专业分类
化学 | 4326篇 |
晶体学 | 39篇 |
力学 | 239篇 |
数学 | 1406篇 |
物理学 | 1474篇 |
出版年
2023年 | 61篇 |
2022年 | 57篇 |
2021年 | 198篇 |
2020年 | 177篇 |
2019年 | 166篇 |
2018年 | 143篇 |
2017年 | 128篇 |
2016年 | 276篇 |
2015年 | 261篇 |
2014年 | 269篇 |
2013年 | 399篇 |
2012年 | 476篇 |
2011年 | 538篇 |
2010年 | 323篇 |
2009年 | 299篇 |
2008年 | 448篇 |
2007年 | 403篇 |
2006年 | 379篇 |
2005年 | 367篇 |
2004年 | 291篇 |
2003年 | 226篇 |
2002年 | 223篇 |
2001年 | 114篇 |
2000年 | 85篇 |
1999年 | 86篇 |
1998年 | 78篇 |
1997年 | 87篇 |
1996年 | 61篇 |
1995年 | 66篇 |
1994年 | 65篇 |
1993年 | 52篇 |
1992年 | 38篇 |
1991年 | 35篇 |
1990年 | 34篇 |
1989年 | 23篇 |
1988年 | 30篇 |
1987年 | 29篇 |
1986年 | 30篇 |
1985年 | 47篇 |
1984年 | 52篇 |
1983年 | 25篇 |
1982年 | 38篇 |
1981年 | 25篇 |
1980年 | 31篇 |
1979年 | 30篇 |
1978年 | 26篇 |
1977年 | 25篇 |
1976年 | 21篇 |
1973年 | 19篇 |
1972年 | 13篇 |
排序方式: 共有7484条查询结果,搜索用时 296 毫秒
11.
For ϕ a δ-subharmonic function, sharp results are obtained that connectA(r, ϕ), B(r, ϕ) andT(r, ϕ), whereA(r, ϕ)=inf|z|=r
ϕ(z),B(r, ϕ)=sup|z|=r
ϕ(z), andT(r, ϕ) is the Nevanlinna characteristics. 相似文献
12.
13.
Marco Biroli Silvia Mataloni Michele Matzeu 《NoDEA : Nonlinear Differential Equations and Applications》2005,12(3):295-321
Some stability results for Mountain Pass and Linking type solutions of semilinear problems involving a very general class
of Dirichlet forms are stated. The non linear terms are supposed to have a suitable superlinear growth and the family of Dirichlet
forms is required to be dominated from below and from above by a fixed diffusion type form. Some concrete examples are also
given. 相似文献
14.
Marco Möller 《Results in Mathematics》2004,46(3-4):271-360
15.
Alberto Mariani Simone Bidali Stefano Fiori Marco Sangermano Giulio Malucelli Roberta Bongiovanni Aldo Priola 《Journal of polymer science. Part A, Polymer chemistry》2004,42(9):2066-2072
By combining frontal polymerization and radical‐induced cationic polymerization, it was possible to cure thick samples of an epoxy monomer bleached by UV light. The effect of the relative amounts of cationic photoinitiator and radical initiator was thoroughly investigated and was related to the front's velocity and its maximum temperature. The materials obtained were characterized by quantitative conversion also in the deeper layers, not reached by UV light. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2066–2072, 2004 相似文献
16.
17.
Some nickel, copper, and silver salts or complexes are efficient catalysts for the oxidation of benzylic ethers with oxygen in 1,2-dimethoxyethane. Salts of the weakly coordinating anion trifluoroacetate are particularly efficient, approaching (and, in some cases, improving) the yields obtained with cobalt(II) chloride, the best catalyst so far reported. 相似文献
18.
Marco Sangermano Mehmet Atilla Tasdelen Yusuf Yagci 《Journal of polymer science. Part A, Polymer chemistry》2007,45(21):4914-4920
Photoinitiated cationic polymerization of mono‐ and bifunctional epoxy monomers, namely cyclohexeneoxide (CHO), 4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexanecarboxylate (EEC), respectively by using sulphonium salts in the presence of hydroxylbutyl vinyl ether (HBVE) was studied. The real‐time FTIR spectroscopic, gel content determination, and thermal characterization studies revealed that both hydroxyl and vinyl ether functionalities of HBVE take part in the polymerization. During the polymerization, HBVE has the ability to react via both active chain end (ACE) and activated monomer mechanisms through its hydroxyl and vinyl ether functionalities, respectively. Thus, more efficient curing was observed with the addition of HBVE into EEC‐containing formulations. It was also demonstrated that HBVE is effective in facilitating the photoinduced crosslinking of monofunctional epoxy monomer, CHO in the absence of a conventional crosslinker. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4914–4920, 2007 相似文献
19.
Marco Lehmann-Waffenschmidt 《Central European Journal of Operations Research》2006,14(3):289-298
It is routine to demonstrate in the exchange economy framework that small changes of individual preferences and endowments always result in small changes of the derived excess demand functions as one should expect. Though being as desirable for reasons of the consistency of the whole approach, however, a precise proof of the converse direction so far is still open to question. The present paper shows that it is actually true. We use a decomposition method for aggregate excess demand functions developed by Mas-Colell which is derived from the well-known decomposition method developed by Sonnenschein and perfected by Debreu and Mantel. Our result fills in a notorious gap in the line of economic justification usually given for this decomposition, or disaggregation, method in that comparative static analysis would be restricted if the decomposition of excess demand functions would not be continuous. 相似文献
20.
Jun Fujii Giancarlo Panaccione Giorgio Rossi Giancarlo Trimarchi 《Surface science》2006,600(18):3884-3887
Bulk carbon impurities segregate at the Fe(1 0 0) surface and, upon thermal annealing, can form metastable surface phases with local and long range order and peculiar electronic properties. We present a surface science study of C-segregated Fe(1 0 0) with scanning tunneling microscopy, angle resolved photoemission, and ab initio calculations of the surface structure and electron states. In particular the c(3√2 × √2) structure, observed for 0.67 atomic layers of C segregated at the iron surface, is found to be due to self-organized carbon stripes made of zig-zag chains. The strong hybridization between C and Fe was observed in ARPES spectra. 相似文献