全文获取类型
收费全文 | 356604篇 |
免费 | 7143篇 |
国内免费 | 5060篇 |
专业分类
化学 | 172052篇 |
晶体学 | 5290篇 |
力学 | 21034篇 |
综合类 | 332篇 |
数学 | 54327篇 |
物理学 | 115772篇 |
出版年
2022年 | 2855篇 |
2021年 | 3718篇 |
2020年 | 4010篇 |
2019年 | 4671篇 |
2018年 | 12663篇 |
2017年 | 13017篇 |
2016年 | 10790篇 |
2015年 | 5020篇 |
2014年 | 7258篇 |
2013年 | 12744篇 |
2012年 | 14622篇 |
2011年 | 22492篇 |
2010年 | 15487篇 |
2009年 | 15807篇 |
2008年 | 19834篇 |
2007年 | 22461篇 |
2006年 | 9943篇 |
2005年 | 13474篇 |
2004年 | 10507篇 |
2003年 | 10076篇 |
2002年 | 8625篇 |
2001年 | 7736篇 |
2000年 | 6035篇 |
1999年 | 4459篇 |
1998年 | 3976篇 |
1997年 | 3794篇 |
1996年 | 3726篇 |
1995年 | 3190篇 |
1994年 | 3348篇 |
1993年 | 3188篇 |
1992年 | 3416篇 |
1991年 | 3554篇 |
1990年 | 3490篇 |
1989年 | 3458篇 |
1988年 | 3279篇 |
1987年 | 3271篇 |
1986年 | 3114篇 |
1985年 | 3755篇 |
1984年 | 3840篇 |
1983年 | 3253篇 |
1982年 | 3192篇 |
1981年 | 3071篇 |
1980年 | 2871篇 |
1979年 | 3353篇 |
1978年 | 3346篇 |
1977年 | 3424篇 |
1976年 | 3547篇 |
1975年 | 3245篇 |
1974年 | 3207篇 |
1973年 | 3386篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
932.
设F(p,q)和G(p,q)在无穷远点的邻域内是分别关于p和q的近似凸函数,且具有二次增长.考虑由F和G构成的一对定义在Soblev空间中的泛函.本文利用blowup技巧,证明了这样一对泛函的Nash平衡点实际上是Lipschitz连续的. 相似文献
933.
V. I. Grafutin V. L. Grishkin G. G. Myasishcheva Yu. V. Funtikov Yu. A. Novikov 《Physics of the Solid State》1998,40(4):549-551
The empirical relation θ
p
6
/I
p=aK (where θ
p is the limiting angle of the parabolic component in the angular distributions of annihilation photons in metals, I
p is the integrated contribution of this component, K=1, 2, 3, ... is an integer, and a is a constant independent of the type of metal) observed earlier has been tested on magnesium, aluminum, copper, zinc, lead,
and bismuth samples. The validity of this relation has been substantiated. The value of the dimensionless constant a has been determined and was found to coincide within experimental error with the result obtained in previous measurements.
It is shown that the value of K for the same metal but for different samples may be different. It is conjectured that this may be due to different defect
concentrations in samples.
Fiz. Tverd. Tela (St. Petersburg) 40, 600–602 (April 1998) 相似文献
934.
A. N. Urumbaev 《Ukrainian Mathematical Journal》1997,49(2):320-326
We show that the modified method for finite-dimensional approximation of solutions of Fredholm integral equations of the first
kind presented in this paper is more economical than traditional methods for finite-dimensional approximation.
Institute of Mathematies, Ukrainian Academy of Science, Kiev. Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 49,
No. 2, pp. 289–295, February, 1997. 相似文献
935.
N. Srinivasan R.C. Johnson N. Kasthurikrishnan P. Wong R.G. Cooks 《Analytica chimica acta》1997,350(3):128-271
An overview of membrane introduction mass spectrometry (MIMS) is presented and comparisons are made with other direct sample introduction techniques. Special attention is given to the unique advantages and the limitations of newer variants on the MIMS technique, including affinity MIMS, reverse-phase and trap MIMS. The salient features of the interfaces used in MIMS are summarized and the various membrane materials commonly used are delineated. The applicability of MIMS is illustrated via discussion of
- 1. (i) bioreactor monitoring (represented by yeast fermentation),
- 2. (ii) environmental monitoring (illustrated by analysis of contaminated ground water samples) and
- 3. (iii) on-line chemical reaction monitoring (exemplified by the photolysis of aryl esters).
936.
937.
Lizeng Wang Chengsong Ma Xiaoli Zhang Yibing Ren Yong Yu 《Fresenius' Journal of Analytical Chemistry》1995,351(7):689-691
The electrochemical behavior of the copper-tyrosine complex has been studied by linear-sweep adsorption voltammetry. In 0.02 mol/L Na2HPO4 buffer solution (pH=9.6), the complex can be adsorped on a hanging mercury drop electrode and reduced at a peak potential of about –0.42 V (vs. SCE). The secondary derivative peak height is linear proportional to the concentration of tyrosine in the range 1.0×10–7–5.0×10–5 mol/L. The detection limit is 5×10–8 mol/L.Project supported by the Provincial Science Foundation of Shandong Province 相似文献
938.
Armenise I. Capitelli M. Colonna G. Koudriavtsev N. Smetanin V. 《Plasma Chemistry and Plasma Processing》1995,15(3):501-528
Plasma Chemistry and Plasma Processing - Nonequilibrium nitrogen dissociation-recombination kinetics in the boundary layer and on the surface of a solid body during hypersonic flow. the subsequent... 相似文献
939.
We study the conjugate boundary-value problem with boundary conditions whose orders can be as large as the order of the differential equation or larger. We construct the Green's function of the problem over the entire space when the separating surface is a hyperplane, and we describe its properties. Bibliography: 6 titles.Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 30, 1989, pp. 20–24. 相似文献
940.