全文获取类型
收费全文 | 79666篇 |
免费 | 546篇 |
国内免费 | 614篇 |
专业分类
化学 | 25569篇 |
晶体学 | 809篇 |
力学 | 6814篇 |
综合类 | 35篇 |
数学 | 32096篇 |
物理学 | 15503篇 |
出版年
2022年 | 48篇 |
2021年 | 63篇 |
2020年 | 63篇 |
2019年 | 77篇 |
2018年 | 10485篇 |
2017年 | 10309篇 |
2016年 | 6122篇 |
2015年 | 937篇 |
2014年 | 382篇 |
2013年 | 446篇 |
2012年 | 3908篇 |
2011年 | 10649篇 |
2010年 | 5714篇 |
2009年 | 6146篇 |
2008年 | 6677篇 |
2007年 | 8818篇 |
2006年 | 325篇 |
2005年 | 1390篇 |
2004年 | 1611篇 |
2003年 | 2023篇 |
2002年 | 1110篇 |
2001年 | 318篇 |
2000年 | 343篇 |
1999年 | 217篇 |
1998年 | 222篇 |
1997年 | 173篇 |
1996年 | 221篇 |
1995年 | 128篇 |
1994年 | 99篇 |
1993年 | 114篇 |
1992年 | 60篇 |
1991年 | 75篇 |
1990年 | 53篇 |
1989年 | 62篇 |
1988年 | 61篇 |
1987年 | 60篇 |
1986年 | 64篇 |
1985年 | 51篇 |
1984年 | 43篇 |
1983年 | 38篇 |
1982年 | 41篇 |
1981年 | 40篇 |
1980年 | 47篇 |
1979年 | 44篇 |
1978年 | 37篇 |
1914年 | 45篇 |
1913年 | 40篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
1.
Zhihong Zhao Bin Wang Rui Tan Wenjing Liu Minghui Zhang 《Magnetic resonance in chemistry : MRC》2022,60(4):427-433
In this study, the transverse relaxation time (T2) of activated carbon (AC) in different relative environment humidity was detected firstly by low-field nuclear magnetic resonance (LFNMR). The pore size (diameter) of AC distributions was calculated by the relationship between T2 and surface relaxation rate (ρ), where ρ was obtained by the detection of nine porous materials with known pore size. The results showed that the pore size distributions of AC calculated by ρ < 0.19 nm/ms were in good agreement with that obtained by nitrogen adsorption method and proved that LFNMR as a new detection method was feasible for characterizing AC pore size distribution. 相似文献
2.
In the paper, the authors establish several integral representations for the generating functions of the large and little Schröder numbers and for the large and little Schröder numbers. 相似文献
3.
Jing Zhihong Ling Baoping Yu Yang Qi Wei Zhang Shufang 《Journal of Sol-Gel Science and Technology》2015,73(1):112-117
Journal of Sol-Gel Science and Technology - A novel gas sensing material, La–Y co-doped TiO2 nanoparticles, was synthesized by sol–gel method and applied to detect organic pollutants... 相似文献
4.
Mesoscopic modeling at the pore scale offers great promise in exploring the underlying structure transport performance of flow through porous media. The present work studies the fluid flow subjected to capillarity-induced resonance in porous media characterized by different porous structure and wettability. The effects of porosity and wettability on the displacement behavior of the fluid flow through porous media are discussed. The results are presented in the form of temporal evolution of percentage saturation and displacement of the fluid front through porous media. The present study reveals that the vibration in the form of acoustic excitation could be significant in the mobilization of fluid through the porous media. The dependence of displacement of the fluid on physicochemical parameters like wettability of the surface, frequency along with the porosity is analyzed. It was observed that the mean displacement of the fluid is more in the case of invading fluid with wetting phase where the driving force strength is not so dominant. 相似文献
5.
6.
Sarah Peluse 《Israel Journal of Mathematics》2018,227(1):379-396
We prove that the group of diffeomorphisms of the interval [0, 1] contains surface groups whose action on (0, 1) has no global fix point and such that only countably many points of the interval (0, 1) have non-trivial stabiliser. 相似文献
7.
8.
9.
10.
S. V. Panin I. V. Vlasov V. P. Sergeev B. B. Ovechkin P. O. Marushchak Sunder Ramasubbu P. S. Lyubutin V. V. Titkov 《Physical Mesomechanics》2015,18(3):261-272
The structure and properties of 12Cr1MoV steel irradiated with a zirconium ion beam were studied by optical microscopy, scanning electron microscopy, and micro- and nanoindentation. It is shown that the modification covers the entire cross-section of the irradiated specimens to a depth of 1 mm. The data on irradiation-induced structural changes are used to interpret the changes in mechanical properties of the irradiated specimens under static and cyclic loading. Particular attention is given to analysis of strain estimation by the digital image correlation method. 相似文献