全文获取类型
收费全文 | 97220篇 |
免费 | 3851篇 |
国内免费 | 2654篇 |
专业分类
化学 | 38156篇 |
晶体学 | 1033篇 |
力学 | 7868篇 |
综合类 | 186篇 |
数学 | 33789篇 |
物理学 | 22693篇 |
出版年
2024年 | 75篇 |
2023年 | 467篇 |
2022年 | 669篇 |
2021年 | 730篇 |
2020年 | 816篇 |
2019年 | 789篇 |
2018年 | 10929篇 |
2017年 | 10723篇 |
2016年 | 6930篇 |
2015年 | 1803篇 |
2014年 | 1385篇 |
2013年 | 1734篇 |
2012年 | 5571篇 |
2011年 | 12241篇 |
2010年 | 6788篇 |
2009年 | 7071篇 |
2008年 | 7790篇 |
2007年 | 9912篇 |
2006年 | 1325篇 |
2005年 | 2278篇 |
2004年 | 2216篇 |
2003年 | 2564篇 |
2002年 | 1562篇 |
2001年 | 669篇 |
2000年 | 694篇 |
1999年 | 619篇 |
1998年 | 543篇 |
1997年 | 511篇 |
1996年 | 503篇 |
1995年 | 410篇 |
1994年 | 376篇 |
1993年 | 338篇 |
1992年 | 248篇 |
1991年 | 260篇 |
1990年 | 226篇 |
1989年 | 170篇 |
1988年 | 144篇 |
1987年 | 146篇 |
1986年 | 117篇 |
1985年 | 90篇 |
1984年 | 85篇 |
1983年 | 60篇 |
1982年 | 66篇 |
1981年 | 56篇 |
1980年 | 60篇 |
1979年 | 44篇 |
1914年 | 45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 15 毫秒
21.
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
22.
He Haidong Yang Haifeng Zhou Longpeng Chen Tianchi 《Journal of Russian Laser Research》2015,36(3):292-299
Ni–Co alloys have a wide range of applications in various fields owning to their excellent physical, chemical, and mechanical properties. In this paper, we prepare Ni–Co alloy coatings on 316L stain steel surfaces by electroplating. We present a novel approach utilizing a nanosecond laser to induce microtextures on Ni–Co alloy coatings. We study experimentally the effects of laser power and scanning rate on the surface morphologies of Ni–Co alloy coatings. The results indicate that the shape and size of induced microtextures can be controlled by the laser power and scanning rate. The size of grains increases with increase in the work current of the laser (WCL) at a certain scanning rate. With the WCL constant, the size of grains decreases with increase in scanning rate while their average height increases. It is a simple and easily-controlled method for the fabrication of microstructures on Ni–Co alloy coatings, which has promising applications in investigations of the properties of microtextured surfaces, such as friction, adhesion, and wetting. 相似文献
23.
In this Letter,a novel system for adaptively correcting the phase of a dynamic multimode beam is proposed.While using merely one spatial light modulator,the phase measurement of the first-order diffraction pattern and the correction of the zeroth diffraction order are simultaneously realized.The real-time experimental result is obtained at a control rate of 10 Hz.The power-in-the-bucket value is improved from 38.5%to 61.8%,even with fundamental mode content that is consistently below 30%.To the best of our knowledge,this is the first implementation of real-time adaptive correction of the entire multimode beam. 相似文献
24.
25.
26.
27.
28.
Zenon Moszner 《Aequationes Mathematicae》2018,92(4):617-625
We give the form of the output function in Ginsburg’s machine in which the input and output dictionaries are abelian groups and the transition function is of a special form. 相似文献
29.
30.
Dr. Masaru Kondo Dr. Shinobu Takizawa Yuzhao Jiang Prof. Dr. Hiroaki Sasai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9866-9869
The Mills reaction and cyclization of readily available 2-aminobenzyl alcohols and nitrosobenzenes using thionyl bromide provided 2H-indazoles in up to 88 % yields. In the metal-free process, acetic acid played a crucial role for the both Mills reaction and cyclization. A brominated 2H-indazole could also be obtained through the one-pot sequence. 相似文献