全文获取类型
收费全文 | 4143篇 |
免费 | 114篇 |
国内免费 | 18篇 |
专业分类
化学 | 2500篇 |
晶体学 | 27篇 |
力学 | 101篇 |
数学 | 514篇 |
物理学 | 1133篇 |
出版年
2023年 | 31篇 |
2022年 | 27篇 |
2021年 | 123篇 |
2020年 | 96篇 |
2019年 | 155篇 |
2018年 | 119篇 |
2017年 | 124篇 |
2016年 | 161篇 |
2015年 | 107篇 |
2014年 | 147篇 |
2013年 | 204篇 |
2012年 | 230篇 |
2011年 | 271篇 |
2010年 | 186篇 |
2009年 | 153篇 |
2008年 | 239篇 |
2007年 | 205篇 |
2006年 | 193篇 |
2005年 | 176篇 |
2004年 | 154篇 |
2003年 | 103篇 |
2002年 | 107篇 |
2001年 | 61篇 |
2000年 | 65篇 |
1999年 | 61篇 |
1998年 | 31篇 |
1997年 | 48篇 |
1996年 | 33篇 |
1995年 | 24篇 |
1994年 | 31篇 |
1993年 | 23篇 |
1992年 | 29篇 |
1991年 | 20篇 |
1990年 | 27篇 |
1989年 | 22篇 |
1988年 | 25篇 |
1987年 | 29篇 |
1986年 | 21篇 |
1984年 | 20篇 |
1983年 | 20篇 |
1982年 | 22篇 |
1980年 | 21篇 |
1978年 | 36篇 |
1977年 | 22篇 |
1975年 | 24篇 |
1974年 | 26篇 |
1973年 | 21篇 |
1971年 | 18篇 |
1968年 | 20篇 |
1967年 | 18篇 |
排序方式: 共有4275条查询结果,搜索用时 200 毫秒
1.
Petrov P. A. Filippova E. A. Kompankov N. B. Sukhikh T. S. Sokolov M. N. 《Journal of Structural Chemistry》2022,63(3):470-475
Journal of Structural Chemistry - A new polymorph of the [ReCl3(MeCN)(PPh3)2] complex is synthesized and characterized by single crystal X-ray diffraction (XRD). Its recrystallization from the... 相似文献
2.
3.
V. A. Bespalov V. M. Glazov E. A. Il’ichev Yu. A. Klimov S. V. Kuklev A. E. Kuleshov R. M. Nabiev G. N. Petrukhin B. G. Potapov G. S. Rychkov D. S. Sokolov V. V. Fandeev E. A. Fetisov S. S. Yakushov 《Technical Physics》2015,60(4):553-560
The results of investigation of optical image detectors designed for the largest problem, near-VUV, range of the spectrum are presented. The possibility of using a dual-stage image detection system to appreciably lower the sensitivity threshold and make computer data processing feasible is considered. The integration of a UV module into a wideband image detector is studied. 相似文献
4.
Crystallography Reports - Nd1 – yEuyF3 – y crystals (y is the molar fraction of EuF2; 0 ≤ y ≤ 0.15) with a tysonite (LaF3) structure have... 相似文献
5.
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
6.
7.
Andrey Vyacheslavovich Vasilyev Valeriya Sergeevna Kuznetsova Tatyana Borisovna Bukharova Timofei Evgenevich Grigoriev Yuriy Dmitrievich Zagoskin Irina Alekseevna Nedorubova Igor Ivanovich Babichenko Sergey Nicolaevich Chvalun Dmitry Vadimovich Goldstein Anatoliy Alekseevich Kulakov 《Molecules (Basel, Switzerland)》2021,26(2)
Compositions based on chitosan/β-glycerophosphate hydrogels with highly porous polylactide granules can be used to obtain moldable bone graft materials that have osteoinductive and osteoconductive properties. To eliminate the influence of such characteristics as chain length, degree of purification, and molecular weight on a designed material, the one-stock chitosan sample was reacetylated to degrees of deacetylation (DD%) of 19.5, 39, 49, 55, and 56. A study of the chitosan/β-glycerophosphate hydrogel with chitosan of a reduced DD% showed that a low degree of deacetylation increased the MSCs (multipotent stromal cells) viability rate in vitro and reduced the leukocyte infiltration in subcutaneous implantation to Wistar rats in vivo. The addition of 12 wt% polylactide granules resulted in optimal composite mechanical and moldable properties, and increased the modulus of elasticity of the hydrogel-based material by approximately 100 times. Excessive filling of the material with PLA (polylactide) granules (more than 20%) led to material destruction at a ~10% strain. Osteoinductive and osteoconductive properties of the chitosan hydrogel-based material with reacetylated chitosan (39 DD%) and highly porous polylactide granules impregnated with BMP-2 (bone morphogenetic protein-2) have been demonstrated in models of orthotopic and ectopic bone formation. When implanted into a critical-size calvarial defect in rats, the optimal concentration of BMP-2 was 10 μg/mL: bone tissue areas filled the entire material’s thickness. Implantation of the material with 50 μg/mL BMP-2 was accompanied with excessive growth of bone tissue and material displacement beyond the defect. Significant osteoinductive and osteoconductive properties of the material with 10 μg/mL of BMP-2 were also shown in subcutaneous implantation. 相似文献
8.
9.
10.