全文获取类型
收费全文 | 2239篇 |
免费 | 70篇 |
国内免费 | 8篇 |
专业分类
化学 | 1715篇 |
晶体学 | 13篇 |
力学 | 35篇 |
数学 | 89篇 |
物理学 | 465篇 |
出版年
2023年 | 15篇 |
2022年 | 14篇 |
2021年 | 17篇 |
2020年 | 48篇 |
2019年 | 32篇 |
2018年 | 12篇 |
2017年 | 17篇 |
2016年 | 38篇 |
2015年 | 33篇 |
2014年 | 33篇 |
2013年 | 91篇 |
2012年 | 112篇 |
2011年 | 140篇 |
2010年 | 63篇 |
2009年 | 62篇 |
2008年 | 134篇 |
2007年 | 108篇 |
2006年 | 135篇 |
2005年 | 127篇 |
2004年 | 141篇 |
2003年 | 101篇 |
2002年 | 100篇 |
2001年 | 62篇 |
2000年 | 36篇 |
1999年 | 34篇 |
1998年 | 28篇 |
1997年 | 24篇 |
1996年 | 38篇 |
1995年 | 27篇 |
1994年 | 30篇 |
1993年 | 24篇 |
1992年 | 22篇 |
1991年 | 18篇 |
1990年 | 20篇 |
1989年 | 20篇 |
1988年 | 15篇 |
1987年 | 15篇 |
1986年 | 14篇 |
1985年 | 37篇 |
1984年 | 32篇 |
1983年 | 18篇 |
1982年 | 24篇 |
1981年 | 18篇 |
1980年 | 24篇 |
1979年 | 27篇 |
1978年 | 17篇 |
1976年 | 16篇 |
1975年 | 21篇 |
1974年 | 18篇 |
1973年 | 10篇 |
排序方式: 共有2317条查询结果,搜索用时 15 毫秒
1.
Hirokazu Nishimura 《International Journal of Theoretical Physics》1995,34(2):211-228
The notion of a manual, introduced and investigated in detail by Foulis, Randall, and their followers, has turned out to be further reaching than its originators had envisaged. Its omnipresence is comparable with the notion of a sheaf, whose significance is well recognized by every pure and applied mathematician. The principal concern of this paper is to give an appropriate vehicle, as general as possible, by which the theory of manuals can be developed. The vehicle is called an orthogonal category, which is akin to the notion of a category with coproducts. Orthogonal categories provide also a new perspective on the notion of a sheaf over a complete Boolean algebra, deepening our comprehension of Boolean mathematics and paving the way to quantum mathematics. 相似文献
2.
Homohelicity induction of a series of propylene-linked zinc bilinone (ZnBL; linear tetrapyrrople-zinc(II) complex) dimers upon complexation with chiral amine and α-amino esters was investigated. Introduction of substituents such as dimethyl and diisobutyl to the central carbon of the propylene spacer gave rise to stabilization of the homohelical (PP and MM) conformers rather than the heterohelical (PM) conformer. As bulkiness of the substituent increased, stability of the homohelical conformers was raised. The preorganization of the homohelical structures led to significantly amplified homohelicity induction upon complexation with chiral amine and α-amino esters. 相似文献
3.
4.
5.
Takanori Ide Hiroshi Isozaki Susumu Nakata Samuli Siltanen Gunther Uhlmann 《纯数学与应用数学通讯》2007,60(10):1415-1442
Let a physical body Ω in ?2 or ?3 be given. Assume that the electric conductivity distribution inside Ω consists of conductive inclusions in a known smooth background. Further, assume that a subset Γ ? ?Ω is available for boundary measurements. It is proved using hyperbolic geometry that certain information about the location of the inclusions can be exactly recovered from static electric measurements on Γ. More precisely: given a ball B with center outside the convex hull of Ω and satisfying (B? ∩ ?Ω) ? Γ, boundary measurements on Γ with explicitly given Dirichlet data are enough to determine whether B intersects the inclusion. An approximate detection algorithm is introduced based on the theory. Numerical experiments in dimension two with simulated noisy data suggest that the algorithm finds the inclusion‐free domain near Γ and is robust against measurement noise. © 2007 Wiley Periodicals, Inc. 相似文献
6.
Susumu Ariki 《Advances in Mathematics》2004,181(1):134-159
This paper determines the representation type of the Iwahori-Hecke algebras of type B when q≠±1. In particular, we show that a single parameter non-semisimple Iwahori-Hecke algebra of type B has finite representation type if and only if q is a simple root of the Poincaré polynomial, confirming a conjecture of Uno's (J. Algebra 149 (1992) 287). 相似文献
7.
Katsunori Nishimura Rie Hidaka Fumitoshi Hirayama Hidetoshi Arima Kaneto Uekama 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):85-88
Geometries, electronic properties and NMR-shielding of cucurbit[5]uril, decamethylcucurbit[5]uril, cucurbit[6]uril, cucurbit[7]uril,
and cucurbit[8]uril are investigated with DFT calculations. All molecules are highly symmetrical with a distinct geometric
flexibility. In addition with a characteristic partial charge distribution these findings account for their chemical complex
building ability. 相似文献
8.
I Kitagawa A Matsuda T Nishimura S Hirai I Yoshioka 《Chemical & pharmaceutical bulletin》1967,15(9):1435-1437
9.
An antiviral nucleoside or virazole was synthesized efficiently and regioselectively starting with benzyl cyanoformate. 相似文献
10.
The first total synthesis of (+)?3-deoxyaphidicolin, a selective inhibitor of eukaryotic DNA polymerase α, has been completed efficiently and stereoselectively starting from 1-abietic acid. 相似文献