全文获取类型
收费全文 | 2392篇 |
免费 | 266篇 |
国内免费 | 235篇 |
专业分类
化学 | 302篇 |
晶体学 | 9篇 |
力学 | 407篇 |
综合类 | 60篇 |
数学 | 1444篇 |
物理学 | 671篇 |
出版年
2024年 | 8篇 |
2023年 | 36篇 |
2022年 | 63篇 |
2021年 | 34篇 |
2020年 | 61篇 |
2019年 | 79篇 |
2018年 | 75篇 |
2017年 | 86篇 |
2016年 | 80篇 |
2015年 | 49篇 |
2014年 | 98篇 |
2013年 | 220篇 |
2012年 | 121篇 |
2011年 | 134篇 |
2010年 | 130篇 |
2009年 | 142篇 |
2008年 | 165篇 |
2007年 | 154篇 |
2006年 | 124篇 |
2005年 | 119篇 |
2004年 | 114篇 |
2003年 | 101篇 |
2002年 | 98篇 |
2001年 | 90篇 |
2000年 | 76篇 |
1999年 | 72篇 |
1998年 | 50篇 |
1997年 | 48篇 |
1996年 | 53篇 |
1995年 | 29篇 |
1994年 | 26篇 |
1993年 | 25篇 |
1992年 | 20篇 |
1991年 | 15篇 |
1990年 | 9篇 |
1989年 | 14篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
排序方式: 共有2893条查询结果,搜索用时 0 毫秒
1.
2.
3.
Song Jiang 《Mathematische Nachrichten》1998,190(1):169-183
We consider initial boundary value problems for the equations of the one-dimensional motion of a viscous, heat-conducting gas with density-dependent viscosity that decreases (to zero) with decreasing density. We prove that if the viscosity does not decrease to zero too rapidly, then smooth solutions exist globally in time. 相似文献
4.
Tsonka Stefanova Baicheva 《Designs, Codes and Cryptography》1998,13(3):223-227
The covering radius of all ternary cyclic codes of length up to 25 is given. Some of the results were obtained by computer
and for others mathematical reasonings were applied. The minimal distances of all codes were recalculated. 相似文献
5.
A new scheme for controlling photodissociation through preparation of a variationally optimized linear superposition of field free vibrational eigenstates is applied for selective control of IBr and HI dissociation. The dependence of photodissociation on various field parameters and initial conditions is examined to investigate the mechanistic basis of selective control. The parametric equations of motion approach for determining vibrational dynamics as a function of field parameters without having to solve the time dependent Schrödinger equation explicitly for each field parameter separately is outlined and its use to identify field characteristics which will provide the requisite population mix represented by the optimal linear superposition of vibrational states is advocated. 相似文献
6.
Tatsien Li 《Mathematical Methods in the Applied Sciences》2006,29(13):1543-1553
By means of a direct and constructive method based on the theory of semi‐global C2 solution, the local exact boundary observability and an implicit duality between the exact boundary controllability and the exact boundary observability are shown for 1‐D quasilinear wave equations with various boundary conditions. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
7.
Ryohei Tsuda Sayaka Kaino Hisashi Kokubo Shin-Ichiro Imabayashi Masayoshi Watanabe 《Colloids and surfaces. B, Biointerfaces》2007,56(1-2):255-Optics
Redox properties of phenothiazine-labeled poly(ethyl glycidy ether)-block-poly(ethylene oxide) (PT-EGEn-b-EOm) are reversibly changed by core-shell micelle formation. In the temperature range higher than the critical micellization temperature (cmt), the anodic potential of PT group positively shifts and concomitantly its anodic current decrease, or levels off compared to those of the reference polymer PT-EOm without the thermo-responsive EGEn segment. The former alteration is caused by incorporation of hydrophobic PT groups into a core of the micelle and the latter by the decrease in the diffusion coefficient of PT groups due to formation of the core-shell micelles. The cmt value and the temperature-dependent alteration in the redox properties strongly depend on the polymer structure, especially the length of thermo-responsive EGEn segment. The electrochemically determined hydrodynamic radii of the polymer aggregates seem to be overestimated, compared to the values reported for the aggregates of other thermo-responsive polymers with similar molecular weights, implying the presence of electrochemically inactive PT groups in the copolymers having longer thermo-responsive segments. 相似文献
8.
Kai-li Xiang 《计算数学(英文版)》2002,(2)
1. IntroductionWe consider a class of direct hybrid methods proposed in [11 for solving the second orderinitial value problemy" = f(t,y), y(0),y'(0) given (1.1)The basic method has the formandHere t. = nh and we define t.l.. = t. I aih, i = 1, 2 and n=0,1… 相似文献
9.
Using the iterative scheme we prove the local existence and uniqueness of solutions of the spherically symmetric Einstein-Vlasov-Maxwell system with small initial data. We prove a continuation criterion to global in-time solutions. 相似文献
10.
M. I. Gil' 《Proceedings of the American Mathematical Society》2003,131(12):3737-3746
A linear operator in a separable Hilbert space is called a quasinormal one if it is a sum of a normal operator and a compact one. In the paper, bounds for the spectrum of quasinormal operators are established. In addition, the lower estimate for the spectral radius is derived. Under some restrictions, that estimate improves the well-known results. Applications to integral operators and matrices are discussed. Our results are new even in the finite-dimensional case.