全文获取类型
收费全文 | 93042篇 |
免费 | 1068篇 |
国内免费 | 514篇 |
专业分类
化学 | 34612篇 |
晶体学 | 885篇 |
力学 | 7115篇 |
数学 | 34491篇 |
物理学 | 17521篇 |
出版年
2023年 | 140篇 |
2022年 | 257篇 |
2021年 | 329篇 |
2020年 | 402篇 |
2019年 | 388篇 |
2018年 | 10600篇 |
2017年 | 10403篇 |
2016年 | 6612篇 |
2015年 | 1304篇 |
2014年 | 841篇 |
2013年 | 1167篇 |
2012年 | 4843篇 |
2011年 | 11692篇 |
2010年 | 6249篇 |
2009年 | 6572篇 |
2008年 | 7491篇 |
2007年 | 9609篇 |
2006年 | 1133篇 |
2005年 | 2114篇 |
2004年 | 2228篇 |
2003年 | 2449篇 |
2002年 | 1512篇 |
2001年 | 417篇 |
2000年 | 428篇 |
1999年 | 299篇 |
1998年 | 307篇 |
1997年 | 272篇 |
1996年 | 364篇 |
1995年 | 220篇 |
1994年 | 187篇 |
1993年 | 216篇 |
1992年 | 139篇 |
1991年 | 157篇 |
1990年 | 122篇 |
1989年 | 131篇 |
1988年 | 142篇 |
1987年 | 131篇 |
1986年 | 126篇 |
1985年 | 145篇 |
1984年 | 147篇 |
1983年 | 98篇 |
1982年 | 160篇 |
1981年 | 161篇 |
1980年 | 143篇 |
1979年 | 128篇 |
1978年 | 150篇 |
1977年 | 111篇 |
1976年 | 91篇 |
1975年 | 88篇 |
1973年 | 96篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Yalda Liaghati Mobarhan Ronald Soong Daniel Lane Andre J. Simpson 《Magnetic resonance in chemistry : MRC》2020,58(5):427-444
Traditionally, due to different hardware requirements, nuclear magnetic resonance (NMR) has developed as two separate fields: one dealing with solids, and one with solutions. Comprehensive multiphase (CMP) NMR combines all electronics and hardware (magic angle spinning [MAS], gradients, high power Radio Frequency (RF) handling, lock, susceptibility matching) into a universal probe that permits a comprehensive study of all phases (i.e., liquid, gel-like, semisolid, and solid), in intact samples. When applied in vivo, it provides unique insight into the wide array of bonds in a living system from the most mobile liquids (blood, fluids) through gels (muscle, tissues) to the most rigid (exoskeleton, shell). In this tutorial, the practical aspects of in vivo CMP NMR are discussed including: handling the organisms, rotor preparation, sample spinning, water suppression, editing experiments, and finishes with a brief look at the potential of other heteronuclei (2H, 15N, 19F, 31P) for in vivo research. The tutorial is aimed as a general resource for researchers interested in developing and applying MAS-based approaches to living organisms. Although the focus here is CMP NMR, many of the approaches can be adapted (or directly applied) using conventional high-resolution magic angle spinning, and in some cases, even standard solid-state NMR probes. 相似文献
12.
13.
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
14.
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
15.
16.
17.
18.
19.
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
20.