全文获取类型
收费全文 | 24908篇 |
免费 | 814篇 |
国内免费 | 123篇 |
专业分类
化学 | 16363篇 |
晶体学 | 138篇 |
力学 | 613篇 |
综合类 | 2篇 |
数学 | 4436篇 |
物理学 | 4293篇 |
出版年
2023年 | 142篇 |
2022年 | 129篇 |
2021年 | 395篇 |
2020年 | 430篇 |
2019年 | 409篇 |
2018年 | 780篇 |
2017年 | 549篇 |
2016年 | 728篇 |
2015年 | 620篇 |
2014年 | 668篇 |
2013年 | 1373篇 |
2012年 | 1501篇 |
2011年 | 1638篇 |
2010年 | 1034篇 |
2009年 | 897篇 |
2008年 | 1484篇 |
2007年 | 1448篇 |
2006年 | 1378篇 |
2005年 | 1271篇 |
2004年 | 1027篇 |
2003年 | 937篇 |
2002年 | 778篇 |
2001年 | 381篇 |
2000年 | 412篇 |
1999年 | 236篇 |
1998年 | 219篇 |
1997年 | 236篇 |
1996年 | 311篇 |
1995年 | 197篇 |
1994年 | 208篇 |
1993年 | 192篇 |
1992年 | 179篇 |
1991年 | 167篇 |
1990年 | 177篇 |
1989年 | 147篇 |
1988年 | 151篇 |
1987年 | 118篇 |
1986年 | 125篇 |
1985年 | 190篇 |
1984年 | 224篇 |
1983年 | 138篇 |
1982年 | 181篇 |
1981年 | 184篇 |
1980年 | 157篇 |
1979年 | 123篇 |
1978年 | 160篇 |
1977年 | 135篇 |
1976年 | 140篇 |
1975年 | 122篇 |
1973年 | 99篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
1.
Fernández Julio R. Gallego Inés Jiménez-Losada Andrés Ordóñez Manuel 《Fuzzy Optimization and Decision Making》2022,21(4):531-551
Fuzzy Optimization and Decision Making - Cost-allocation problems in a fixed network are concerned with distributing the costs for use by a group of clients who cooperate in order to reduce such... 相似文献
2.
3.
Kavitha Telikepalli Király Tamás Matuschke Jannik Schlotter Ildikó Schmidt-Kraepelin Ulrike 《Mathematical Programming》2022,192(1-2):567-595
Mathematical Programming - Let G be a digraph where every node has preferences over its incoming edges. The preferences of a node extend naturally to preferences over branchings, i.e., directed... 相似文献
4.
Peralta Cecilia Mariana Acosta Gimena Henestrosa Cecilia Gil Raúl Andrés Fernández Liliana Patricia 《Journal of Analytical Chemistry》2022,77(3):308-317
Journal of Analytical Chemistry - The present development involved a flow injection strategy using a mini-column of multiwalled carbon nanotubes and fluorescent detection (λex of 283 nm,... 相似文献
5.
A CE instrument that can be assembled from commercially available components with minimal construction effort is described. Except for the electronic control circuitry no specially made parts are required. It is based on a flexible design of microfluidic, electropneumatic, and electronic sections and different configurations can easily be implemented. Automated injection into the capillary is performed hydrodynamically by the application of a pressure for a controlled length of time. The performance of the device was tested with a contactless conductivity detector by separating different metal ions. In addition, nine metal cations related to the quality of honey were separated in 2.3 min and four honey samples were analysed quantitatively to demonstrate the applicability of the method. 相似文献
6.
Lluís Jofre Stefan P. Domino Gianluca Iaccarino 《Flow, Turbulence and Combustion》2018,100(2):341-363
Motivated by the sizable increase of available computing resources, large-eddy simulation of complex turbulent flow is becoming increasingly popular. The underlying filtering operation of this approach enables to represent only large-scale motions. However, the small-scale fluctuations and their effects on the resolved flow field require additional modeling. As a consequence, the assumptions made in the closure formulations become potential sources of incertitude that can impact the quantities of interest. The objective of this work is to introduce a framework for the systematic estimation of structural uncertainty in large-eddy simulation closures. In particular, the methodology proposed is independent of the initial model form, computationally efficient, and suitable to general flow solvers. The approach is based on introducing controlled perturbations to the turbulent stress tensor in terms of magnitude, shape and orientation, such that propagation of their effects can be assessed. The framework is rigorously described, and physically plausible bounds for the perturbations are proposed. As a means to test its performance, a comprehensive set of numerical experiments are reported for which physical interpretation of the deviations in the quantities of interest are discussed. 相似文献
7.
Dr. Silvia Castro-Fernández Carlos M. Cruz Dr. Inês F. A. Mariz Dr. Irene R. Márquez Vicente G. Jiménez Lucía Palomino-Ruiz Prof. Juan M. Cuerva Dr. Ermelinda Maçôas Dr. Araceli G. Campaña 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(18):7205-7211
A new family of distorted ribbon-shaped nanographenes was designed, synthesized, and their optical and electrochemical properties were evaluated, pointing out an unprecedented correlation between their structural characteristics and the two-photon absorption (TPA) responses and electrochemical band gaps. Three nanographene ribbons have been prepared: a seven-membered-ring-containing nanographene presenting a tropone moiety at the edge, its full-carbon analogue, and a purely hexagonal one. We have found that the TPA cross-sections and the electrochemical band gaps of the seven-membered-ring-containing compounds are higher and lower, respectively, than those of the fully hexagonal polycyclic aromatic hydrocarbon (PAH). Interestingly, the inclusion of additional curvature has a positive effect in terms of non-linear optical properties of those ribbons. 相似文献
8.
9.
10.