全文获取类型
收费全文 | 45715篇 |
免费 | 4752篇 |
国内免费 | 3505篇 |
专业分类
化学 | 32162篇 |
晶体学 | 729篇 |
力学 | 1836篇 |
综合类 | 298篇 |
数学 | 4713篇 |
物理学 | 14234篇 |
出版年
2023年 | 440篇 |
2022年 | 508篇 |
2021年 | 1092篇 |
2020年 | 1180篇 |
2019年 | 1313篇 |
2018年 | 1068篇 |
2017年 | 1060篇 |
2016年 | 1668篇 |
2015年 | 1642篇 |
2014年 | 2020篇 |
2013年 | 3081篇 |
2012年 | 3782篇 |
2011年 | 4014篇 |
2010年 | 2892篇 |
2009年 | 2658篇 |
2008年 | 3484篇 |
2007年 | 2961篇 |
2006年 | 3026篇 |
2005年 | 2640篇 |
2004年 | 2233篇 |
2003年 | 1822篇 |
2002年 | 1803篇 |
2001年 | 1197篇 |
2000年 | 957篇 |
1999年 | 689篇 |
1998年 | 436篇 |
1997年 | 389篇 |
1996年 | 449篇 |
1995年 | 367篇 |
1994年 | 387篇 |
1993年 | 371篇 |
1992年 | 263篇 |
1991年 | 250篇 |
1990年 | 204篇 |
1989年 | 174篇 |
1988年 | 131篇 |
1987年 | 114篇 |
1986年 | 105篇 |
1985年 | 133篇 |
1984年 | 86篇 |
1983年 | 72篇 |
1982年 | 91篇 |
1981年 | 101篇 |
1980年 | 56篇 |
1979年 | 76篇 |
1978年 | 63篇 |
1977年 | 59篇 |
1976年 | 62篇 |
1975年 | 51篇 |
1974年 | 57篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
The surface charge is a key concept in electrochemistry. Mathematically, the surface charge is obtained from a spatial integration of the volume charge along a particular direction. Ambiguities thus arise in choosing the starting and ending points of the integration. As for electrocatalytic interfaces, the presence of chemisorbates further complicates the situation. In this minireview, I adopt a definition of the surface charge within a continuum picture of the electric double layer. I will introduce surface charging behaviors of firstly ordinary electrochemical interfaces and then electrocatalytic interfaces featuring partially charged chemisorbates. Particularly, the origin of nonmonotonic surface charging behaviors of electrocatalytic interfaces is explained using a primitive model. Finally, a brief account of previous studies on the nonmonotonic surface charging behavior is presented, as a subline of the spectacular history of electric double layer. 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.
Mohammad A. Khalilzadeh Soo Young Kim Ho Won Jang Rafael Luque Rajender S. Varma Richard A. Venditti Mohammadreza Shokouhimehr 《Materials Today Chemistry》2022
The requirement of green and sustainable materials to prepare heterogeneous catalysts has intensified for practical reasons over the past few decades. Carbohydrates are possibly the most plentiful and renewable organic materials in nature with inimitable physiochemical properties, plausible low-cost and large-scale production, and sustainability features could be exploited in the generation of nanostructured heterogeneous catalysts. This review article outlines the organic transformations catalyzed by diverse carbohydrate-based nanostructured catalysts in greener and environmentally friendly processes. Selected examples are highlighted for a variety of organic reactions exploiting the proposed catalysts’ reactivity and reusability, and interactions with the intrinsic nature of the applied carbohydrate supports; advantages and speculated challenges of the introduced catalysts are deliberated as well. 相似文献
4.
Annals of Global Analysis and Geometry - We study harmonic maps from a 3-manifold with boundary to $$\mathbb {S}^1$$ and prove a special case of Gromov dihedral rigidity of three-dimensional cubes... 相似文献
5.
6.
Duh Yih-Shing Lin Ying-Cih Ho Ta-Cheng Kao Chen-Shan 《Journal of Thermal Analysis and Calorimetry》2022,147(21):12005-12018
Journal of Thermal Analysis and Calorimetry - Thermal runaway phenomena of the Panasonic 21,700 LiNi0.8Co0.15Al0.05O2 lithium-ion batteries with 100, 50 and 25% capacity were studied under thermal... 相似文献
7.
In this paper,we investigate the non-autonomous Hamilton-Jacobi equation ■ where H is 1-periodic with respect to t and M is a compact Riemannian manifold without boundary.We obtain the viscosity solution denoted by T_(t_0)~tφ(x) and show T_(t_0)~tφ(x) converges uniformly to a time-periodic viscosity solution u~*(x,t) of ?_tu+H(t,x,?_xu,u)=0. 相似文献
8.
9.
Journal of Fluorescence - We synthesized an original reversible colorimetric chemosensor PDJ... 相似文献
10.
利用等离子增强原子层沉积技术(PEALD)在c面蓝宝石衬底上制备了氧化镓(Ga2O3)薄膜,研究了退火气氛(v(N2)∶v(O2)=1∶1(体积比)、空气和N2)及退火时间对Ga2O3薄膜晶体结构、表面形貌和光学性质的影响。研究结果表明,退火前的氧化镓处于亚稳态,不同退火气氛下退火后晶体结构发生明显改变,而且退火气氛中N2比例增加有利于Ga2O3重结晶。在N2气氛下退火达到30 min,薄膜结构已由亚稳态转变成择优取向的β-Ga2O3。而且表面形貌分析表明,退火30 min后表面形貌开始趋于稳定,表面晶粒密度不再增加。另外实验样品在 400~800 nm的平均透射率几乎是100%,且光吸收边陡峭。采用N2气氛退火,对于富氧环境下沉积的Ga2O3更利于薄膜表面原子迁移,以及择优取向Ga2O3重结晶。 相似文献