全文获取类型
收费全文 | 2093篇 |
免费 | 81篇 |
国内免费 | 14篇 |
专业分类
化学 | 1128篇 |
晶体学 | 8篇 |
力学 | 95篇 |
综合类 | 1篇 |
数学 | 633篇 |
物理学 | 323篇 |
出版年
2023年 | 10篇 |
2022年 | 26篇 |
2021年 | 43篇 |
2020年 | 44篇 |
2019年 | 42篇 |
2018年 | 46篇 |
2017年 | 35篇 |
2016年 | 74篇 |
2015年 | 71篇 |
2014年 | 78篇 |
2013年 | 135篇 |
2012年 | 140篇 |
2011年 | 133篇 |
2010年 | 92篇 |
2009年 | 86篇 |
2008年 | 107篇 |
2007年 | 120篇 |
2006年 | 102篇 |
2005年 | 104篇 |
2004年 | 92篇 |
2003年 | 85篇 |
2002年 | 73篇 |
2001年 | 28篇 |
2000年 | 30篇 |
1999年 | 27篇 |
1998年 | 16篇 |
1997年 | 27篇 |
1996年 | 32篇 |
1995年 | 17篇 |
1994年 | 20篇 |
1993年 | 15篇 |
1992年 | 15篇 |
1991年 | 19篇 |
1990年 | 17篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1985年 | 21篇 |
1984年 | 15篇 |
1983年 | 12篇 |
1982年 | 13篇 |
1981年 | 16篇 |
1980年 | 13篇 |
1979年 | 12篇 |
1978年 | 4篇 |
1977年 | 17篇 |
1976年 | 7篇 |
1975年 | 8篇 |
1973年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有2188条查询结果,搜索用时 15 毫秒
1.
Luc Illusie 《Japanese Journal of Mathematics》2006,1(1):107-136
We discuss classical questions concerning traces of elements of Galois groups or correspondences in ℓ-adic cohomology, mostly
over finite or local fields, such as rationality and independence of ℓ, integrality, congruences modulo powers of ℓ or p. We report on the progress that has been made on this topic during the past ten years. 相似文献
2.
Luc Martinon Stéphane Azoulay E. Peter Kündig 《Journal of organometallic chemistry》2004,689(23):3831-3836
A Pd-catalyzed three-component assembling of highly functionalized 4-benzyl-(and allyl-)pyrrolidines was achieved based on a combination of allyl amines, gem-diactivated alkenes, and unsaturated halides (or triflate). 相似文献
3.
Jocelyn Sabatier Serge Poullain Patrick Latteux Jean Luc Thomas Alain Oustaloup 《Nonlinear dynamics》2004,38(1-2):383-400
Robust speed control of a low damped electromechanical system with backlash is studied, controlled load angular speed being not measured. The proposed control strategy combines a Luenberger observer (load angular speed and load torque disturbance estimations) and a robust CRONE controller. The observer provides estimation of the load angular speed and of the disturbance torque applied on the load. Through the computation of only three independent parameters (as many as a PID controller), the CRONE controller permits to ensure the robust speed control of the load in spite of plant parametric variations and speed observation errors. The proposed control strategy is applied to a four mass experimental test bench. 相似文献
4.
Ccile Nouvel Philippe Dubois Edith Dellacherie Jean‐Luc Six 《Journal of polymer science. Part A, Polymer chemistry》2004,42(11):2577-2588
The whole controlled synthesis of novel amphiphilic polylactide (PLA)‐grafted dextran copolymers was achieved. The control of the architecture of such biodegradable and potentially biocompatible copolymers has required a three‐step synthesis based on the “grafting from” concept. The first step consisted of the partial silylation of the dextran hydroxyl groups. This protection step was followed by the ring‐opening polymerization of D ,L ‐lactide initiated from the remaining OH functions of the partially silylated polysaccharide. The third step involved the silylether group deprotection under very mild conditions. Based on previous studies, in which the control of the first step was achieved, this study is focused on the last two steps. Experimental conditions were investigated to ensure a controlled polymerization of D ,L ‐lactide, in terms of grafting efficiency, graft length, and transesterification limitation. After polymerization, the final step was studied in order to avoid degradation of both polysaccharide backbone and polyester grafts. The chemical stability of dextran backbone was checked throughout each step of the synthesis. PLA‐grafted dextrans and PLA‐grafted (silylated dextrans) were proved to adopt a core‐shell conformation in various solvents. Furthermore, preliminary experiments on the potential use of these amphiphilic grafted copolymers as liquid/liquid interface stabilizers were performed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2577–2588, 2004 相似文献
5.
We prove that in some reasonable sense, every possible physical law can be reformulated in terms of symmetries. This result explains the well-known success of the group-theoretic approach in physics. 相似文献
6.
Characterizations of the containment of a convex set either in an arbitrary convex set or in the complement of a finite union
of convex sets (i.e., the set, described by reverse-convex inequalities) are given. These characterizations provide ways of
verifying the containments either by comparing their corresponding dual cones or by checking the consistency of suitable associated
systems. The convex sets considered in this paper are the solution sets of an arbitrary number of convex inequalities, which
can be either weak or strict inequalities. Particular cases of dual characterizations of set containments have played key
roles in solving large scale knowledge-based data classification problems where they are used to describe the containments
as inequality constraints in optimization problems. The idea of evenly convex set (intersection of open half spaces), which
was introduced by W. Fenchel in 1952, is used to derive the dual conditions, characterizing the set containments. 相似文献
7.
Luc Hillairet 《Annales Henri Poincare》2006,7(4):689-710
We consider Riemannian surfaces in which there are many embedded Euclidean cylinders. We show that quantitative assumptions
on the number of such cylinders provide estimates for the counting function of eigenvalues. These results in particular apply
to translation surfaces.
Communicated by Jens Marklof
Submitted: 3/03/ 2005 Accepted: 18/11/2005 相似文献
8.
9.
New concepts for the study of incompressible plane or axisymmetric flows are analysed by the stream tube method. Flows without eddies and pure vortex flows are considered in a transformed domain where the mapped streamlines are rectilinear or circular. The transformation between the physical domain and the computational domain is an unknown of the problem. In order to solve the non-linear set of relevant equations, we present a new algorithm based on a trust region technique which is effective for non-convex optimization problems. Experimental results show that the new algorithm is more robust compared to the Newton-Raphson method. 相似文献
10.