全文获取类型
收费全文 | 36773篇 |
免费 | 5951篇 |
国内免费 | 4468篇 |
专业分类
化学 | 25977篇 |
晶体学 | 425篇 |
力学 | 2518篇 |
综合类 | 295篇 |
数学 | 4374篇 |
物理学 | 13603篇 |
出版年
2024年 | 74篇 |
2023年 | 751篇 |
2022年 | 830篇 |
2021年 | 1169篇 |
2020年 | 1536篇 |
2019年 | 1404篇 |
2018年 | 1236篇 |
2017年 | 1129篇 |
2016年 | 1746篇 |
2015年 | 1706篇 |
2014年 | 2033篇 |
2013年 | 2590篇 |
2012年 | 3253篇 |
2011年 | 3379篇 |
2010年 | 2343篇 |
2009年 | 2143篇 |
2008年 | 2496篇 |
2007年 | 2118篇 |
2006年 | 2109篇 |
2005年 | 1681篇 |
2004年 | 1354篇 |
2003年 | 1102篇 |
2002年 | 1072篇 |
2001年 | 853篇 |
2000年 | 760篇 |
1999年 | 900篇 |
1998年 | 677篇 |
1997年 | 577篇 |
1996年 | 643篇 |
1995年 | 550篇 |
1994年 | 497篇 |
1993年 | 401篇 |
1992年 | 375篇 |
1991年 | 329篇 |
1990年 | 267篇 |
1989年 | 213篇 |
1988年 | 195篇 |
1987年 | 143篇 |
1986年 | 112篇 |
1985年 | 98篇 |
1984年 | 72篇 |
1983年 | 61篇 |
1982年 | 33篇 |
1981年 | 38篇 |
1980年 | 21篇 |
1978年 | 9篇 |
1976年 | 13篇 |
1975年 | 12篇 |
1973年 | 10篇 |
1957年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
81.
82.
The results of laser induced deposition of copper on polyimide substrate from copper electrolyte solution are reported. Unlike most work reported in the literatures where CW Ar+ lasers were used, a second harmonic (532 nm wavelength) Q-switch Nd:YAG laser was used for our experiments. The deposition process was conducted by laser-catalyzing of the polyimide surface and subsequent photothermal-accelerated reduction of copper-complex ions in an alkaline reducing environment. The characteristics of the deposited copper line were investigated in terms of laser beam scanning speed, and the number of scans. The surface morphology and chemical composition of the deposited copper were analyzed using field emission scanning electron microscope (FESEM) and energy dispersive spectrometer (EDX). The optimum processing conditions have been identified. The copper deposit was found to adhere well to the substrate. 相似文献
83.
84.
85.
86.
利用变分法证明平面调和函数的外问题的确切形式;在此基础上,建立外问题的具有间接变量的等价边界积分方程;传统的外问题及边界积分方程不具有普遍适用性,本文对此进行了详细的讨论. 相似文献
87.
Equilibrium Problems with Applications to Eigenvalue Problems 总被引:5,自引:0,他引:5
In this paper, we consider equilibrium problems and introduce the concept of (S)+ condition for bifunctions. Existence results for equilibrium problems with the (S)+ condition are derived. As special cases, we obtain several existence results for the generalized nonlinear variational inequality studied by Ding and Tarafdar (Ref. 1) and the generalized variational inequality studied by Cubiotti and Yao (Ref. 2). Finally, applications to a class of eigenvalue problems are given. 相似文献
88.
89.
We consider a useful modification of the inexact implicit method with a variable parameter in Wang et al. J Optim Theory 111:
431–443 (2001) for generalized mixed monotone variational inequalities. One of the contributions of the proposed method in
this paper is that the restrictions imposed on the variable parameter are weaker than the ones in Wang et al. J Optim Theory
111: 431–443 (2001). Another contribution is that we establish a sufficient and necessary condition for the convergence of
the proposed method to a solution of the general mixed monotone variational inequality. 相似文献
90.
ZHU Yabin ZHOU Yueliang LIU Zhen WANG Shufang CHEN Zhenghao U Huibin YANG Guozhen XlAO Ling Ren Hongtao JIAO Yulei Zheng Minghui 《中国科学G辑(英文版)》2004,47(2):165-172
The irreversibility field (Hirr) of Y-based superconductor is much higher than that of Bi-based superconductor. Y-based superconductor is capable of maintaining stable electrical currents in high magnetic field and electric field, so it is a better suited mate-rial for electric-current applications. Commonly, the Y-based tapes comprise a YBCO thick film deposited on a flexible substrate, typically with an intermediate buffer layer, and an overcoat of noble metal. In this process, the interm… 相似文献