全文获取类型
收费全文 | 158720篇 |
免费 | 1180篇 |
国内免费 | 515篇 |
专业分类
化学 | 67790篇 |
晶体学 | 2094篇 |
力学 | 10104篇 |
综合类 | 1篇 |
数学 | 40204篇 |
物理学 | 40222篇 |
出版年
2022年 | 672篇 |
2021年 | 1010篇 |
2020年 | 1061篇 |
2019年 | 1280篇 |
2018年 | 12031篇 |
2017年 | 11921篇 |
2016年 | 8336篇 |
2015年 | 1995篇 |
2014年 | 2227篇 |
2013年 | 4004篇 |
2012年 | 6852篇 |
2011年 | 13913篇 |
2010年 | 8384篇 |
2009年 | 8763篇 |
2008年 | 9666篇 |
2007年 | 11689篇 |
2006年 | 3155篇 |
2005年 | 3853篇 |
2004年 | 3881篇 |
2003年 | 4135篇 |
2002年 | 3274篇 |
2001年 | 2538篇 |
2000年 | 2003篇 |
1999年 | 1458篇 |
1998年 | 1352篇 |
1997年 | 1221篇 |
1996年 | 1118篇 |
1995年 | 979篇 |
1994年 | 918篇 |
1993年 | 940篇 |
1992年 | 946篇 |
1991年 | 1017篇 |
1990年 | 941篇 |
1989年 | 989篇 |
1988年 | 901篇 |
1987年 | 840篇 |
1986年 | 810篇 |
1985年 | 936篇 |
1984年 | 1026篇 |
1983年 | 875篇 |
1982年 | 892篇 |
1981年 | 806篇 |
1980年 | 761篇 |
1979年 | 827篇 |
1978年 | 939篇 |
1977年 | 939篇 |
1976年 | 837篇 |
1975年 | 806篇 |
1974年 | 808篇 |
1973年 | 793篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
41.
Valiullina Z. R. Ivanova N. A. Shitikova O. V. Miftakhov M. S. 《Russian Journal of Organic Chemistry》2019,55(8):1131-1135
Russian Journal of Organic Chemistry - Methyl (Z)-3-[(2R,3R,4S,5S)-5-(2-methoxy-2-oxoethyl)-3,4-(isopropylidenedioxy)tetrahydrofuran-2-yl]-prop-2-enoate was synthesized, and its intramolecular... 相似文献
42.
E. V. Shadrina O. N. Malinkina T. G. Khonina A. B. Shipovskaya V. I. Fomina E. Yu. Larchenko N. A. Popova I. G. Zyryanova L. P. Larionov 《Russian Chemical Bulletin》2015,64(7):1633-1639
The biomimetic sol—gel synthesis of silicon—chitosan-containing glycerohydrogels was carried out using silicon tetraglycerolate as a precursor. It was found that chitosan accelerates gel formation in weakly acidic media. In more acidic media, the kinetics of the process changes according to the curve with a maximum, which can be attributed to different mechanisms of silanol condensation before and after the isoelectric point. The investigated silicon—chitosan-containing glycerohydrogels exhibit antibacterial, anti-inflammatory, and wound healing activity. The synthesized hybrid glycerohydrogels are promising materials for biomedical applications. 相似文献
43.
Valentin A. Semenov Dmitry O. Samultsev Leonid B. Krivdin 《Magnetic resonance in chemistry : MRC》2020,58(6):532-539
The density functional theory calculation of 1H and 13C NMR chemical shifts in a series of ten 10 classically known Strychnos alkaloids with a strychnine skeleton was performed at the PBE0/pcSseg-2//pcseg-2 level. It was found that calculated 1H and 13C NMR chemical shifts provided a markedly good correlation with experiment characterized by a mean absolute error of 0.08 ppm in the range of 7 ppm for protons and 1.67 ppm in the range of 150 ppm for carbons, so that a mean absolute percentage error was as small as ~1% in both cases. 相似文献
44.
Kacimi Rachid Bourass Mohamed Toupance Thierry Wazzan Nuha Chemek Mourad El Alamy Aziz Bejjit Lahcen Alimi Kamel Bouachrine Mohammed 《Research on Chemical Intermediates》2020,46(6):3247-3262
Research on Chemical Intermediates - A theoretical study on four organic dyes based on bis(4-hexyloxy)triphenylamine as donor and electron acceptor cyanoacrylic acid with a... 相似文献
45.
JETP Letters - At the resonant passage of a plane elastic shear wave through an acoustically continuous heterostructure consisting of magnetic and nonmagnetic layers in a symmetric nonmagnetic... 相似文献
46.
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
47.
Kondakov N. N. Mel´nikova T. M. Chekryzhova T. V. Mel´nikova M. V. Zinin A. I. Torgov V. I. Chizhov A. O. Kononov L. O. 《Russian Chemical Bulletin》2015,64(5):1142-1148
Russian Chemical Bulletin - Terminal disaccharide fragment of phenolic glycolipid from Mycobacterium leprae (PGL-I) was synthesized as a glycoside with 4-(2-aminoethoxy)phenyl aglycon. The obtained... 相似文献
48.
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
49.
50.