全文获取类型
收费全文 | 4579篇 |
免费 | 186篇 |
国内免费 | 29篇 |
专业分类
化学 | 2488篇 |
晶体学 | 39篇 |
力学 | 177篇 |
数学 | 1213篇 |
物理学 | 877篇 |
出版年
2023年 | 41篇 |
2022年 | 71篇 |
2021年 | 130篇 |
2020年 | 134篇 |
2019年 | 161篇 |
2018年 | 159篇 |
2017年 | 149篇 |
2016年 | 201篇 |
2015年 | 157篇 |
2014年 | 218篇 |
2013年 | 349篇 |
2012年 | 319篇 |
2011年 | 332篇 |
2010年 | 186篇 |
2009年 | 198篇 |
2008年 | 246篇 |
2007年 | 213篇 |
2006年 | 162篇 |
2005年 | 128篇 |
2004年 | 131篇 |
2003年 | 95篇 |
2002年 | 79篇 |
2001年 | 69篇 |
2000年 | 47篇 |
1999年 | 34篇 |
1998年 | 25篇 |
1997年 | 31篇 |
1996年 | 49篇 |
1995年 | 40篇 |
1994年 | 32篇 |
1993年 | 42篇 |
1992年 | 35篇 |
1991年 | 38篇 |
1990年 | 32篇 |
1989年 | 22篇 |
1988年 | 27篇 |
1987年 | 34篇 |
1986年 | 36篇 |
1985年 | 32篇 |
1984年 | 26篇 |
1983年 | 25篇 |
1982年 | 30篇 |
1981年 | 29篇 |
1980年 | 22篇 |
1979年 | 37篇 |
1978年 | 25篇 |
1977年 | 21篇 |
1976年 | 23篇 |
1975年 | 20篇 |
1974年 | 15篇 |
排序方式: 共有4794条查询结果,搜索用时 97 毫秒
1.
Bao Nguyen Xuan Duy Khanh Phan Quoc Tung Nguyen Minh 《Set-Valued and Variational Analysis》2022,30(2):465-486
Set-Valued and Variational Analysis - We aim to establish Karush-Kuhn-Tucker multiplier rules involving higher-order complementarity slackness under Hölder metric subregularity. These rules... 相似文献
2.
Luan Nguyen Ngoc Kim Do Sang Yen Nguyen Dong 《Journal of Optimization Theory and Applications》2022,193(1):574-597
Journal of Optimization Theory and Applications - We consider the conic linear program given by a closed convex cone in an Euclidean space and a matrix, where vector on the right-hand side of the... 相似文献
3.
4.
Phan Quoc Khanh 《Numerical Functional Analysis & Optimization》2018,39(1):100-125
We propose a definition of a generalized type of Knaster–Kuratowski–Mazurkiewicz (KKM) mappings, called a weak T-KKM mapping, and a corresponding weak KKM property. A new extension of the Fan–Glicksberg fixed-point theorem is established. Sufficient conditions for the existence of a continuous selection, a fixed point of a composition, and a coincidence point are also provided. Then, we use the obtained results to study the existence of solutions to various optimization-related problems. Discussions and detailed examples are included as well to compare our results with existing ones and to explain their advantages in many situations. 相似文献
5.
Pham Duy Khanh Tran Hong Mo Trinh T. T. Tran 《Numerical Functional Analysis & Optimization》2019,40(8):924-943
Necessary and sufficient conditions for qualitative properties of infinite dimensional linear programing problems such as solvability, duality, and complementary slackness conditions are studied in this article. As illustrations for the results, we investigate the parametric version of Gale’s example. 相似文献
6.
Nonlinear Dynamics - Based on bifurcation theory, nonlinear frequency response analysis is a recent development in the field of flight dynamics studies. Here, we consider how this method can be... 相似文献
7.
Tran Thu Ha Nguyen Hong Phong François-Xavier Le Dimet Hong Son Hoang 《Comptes Rendus Mecanique》2019,347(5):423-444
This article presents a correction method for a better resolution of the problem of estimating and predicting pollution, governed by Burgers' equations. The originality of the method consists in the introduction of an error function into the system's equations of state to model uncertainty in the model. The initial conditions and diffusion coefficients, present in the equations for pollution and concentration, and also those in the model error equations, are estimated by solving a data assimilation problem. The efficiency of the correction method is compared with that produced by the traditional method without introduction of an error function.Three test cases are presented in this study in order to compare the performances of the proposed methods. In the first two tests, the reference is the analytical solution and the last test is formulated as part of the “twin experiment”.The numerical results obtained confirm the important role of the model error equation for improving the prediction capability of the system, in terms of both accuracy and speed of convergence. 相似文献
8.
Dr. Chaolu Eerdun Thi Hien Thuy Nguyen Takuya Okayama Satoshi Hisanaga Prof. Dr. Jun-ichiro Setsune 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(22):5777-5786
The hexapyrrole-α,ω-dicarbaldehydes 1 a and 1 b were metallated with CuII, NiII, and PdII to give bimetallic complexes where a pair of 3 N+O four-coordinate metal planes are helically distorted and the central 2,2′-bipyrrole subunit adopts a cis or trans conformation. X-ray crystallographic analysis of the bisCu complex revealed a closed form with a cis-2,2′-bipyrrole subunit and an open form with a trans-2,2′-bipyrrole subunit. The bisPd complexes took a closed form both in the solid state and in solution. They are regarded as single helicates of two turns and the energy barrier for the interchange between an M helix and a P helix was remarkably influenced by the bulky 3,3′-substituent of the central 2,2′-bipyrrole subunit. Although the bisNi complexes adopt a closed form in the solid state, they exist as a homohelical open C2-symmetric form or a heterohelical open Ci-symmetric form in solution. A theoretical study suggested that the closed form of 1 a Pd was stabilized by the Pd–Pd interaction. Compound 1 a Pd was reversibly oxidized by one electron at 0.14 V versus ferrocene/ferrocenium (Fc/Fc+) and this oxidized species showed Vis/NIR absorption bands at λ=767 and 1408 nm. 相似文献
9.
Phu H. Dang Linh T. T. Nguyen Hue T. T. Nguyen Tho H. Le Truong N. V. Do Hai X. Nguyen 《Natural product research》2019,33(20):2883-2889
From an EtOAc-soluble fraction of the stem barks of Swintonia floribunda (Anacardiaceae), one new dimeric alkylresorcinol named integracin E (1), together with 4 known compounds (2–5) were isolated. Their chemical structures were elucidated based on the spectroscopic data interpretation. The absolute configuration of 1 was determined by the specific rotation analysis of its acid-catalyzed hydrolysis product. Compound 1 showed potent tyrosinase inhibitory activity with an IC50 value of 48.2?μM. 相似文献
10.
Nguyen Van Hung Vo Minh Tam Dumitru Baleanu 《Mathematical Methods in the Applied Sciences》2020,43(7):4614-4626
In this paper, we consider a class of split mixed vector quasivariational inequality problems in real Hilbert spaces and establish new gap functions by using the method of the nonlinear scalarization function. Further, we obtain some error bounds for the underlying split mixed vector quasivariational inequality problems in terms of regularized gap functions. Finally, we give some examples to illustrate our results. The results obtained in this paper are new. 相似文献