全文获取类型
收费全文 | 19036篇 |
免费 | 2910篇 |
国内免费 | 2310篇 |
专业分类
化学 | 13668篇 |
晶体学 | 199篇 |
力学 | 1228篇 |
综合类 | 148篇 |
数学 | 2229篇 |
物理学 | 6784篇 |
出版年
2024年 | 23篇 |
2023年 | 398篇 |
2022年 | 435篇 |
2021年 | 600篇 |
2020年 | 722篇 |
2019年 | 740篇 |
2018年 | 602篇 |
2017年 | 574篇 |
2016年 | 880篇 |
2015年 | 825篇 |
2014年 | 1079篇 |
2013年 | 1372篇 |
2012年 | 1587篇 |
2011年 | 1708篇 |
2010年 | 1189篇 |
2009年 | 1110篇 |
2008年 | 1337篇 |
2007年 | 1112篇 |
2006年 | 991篇 |
2005年 | 879篇 |
2004年 | 711篇 |
2003年 | 593篇 |
2002年 | 647篇 |
2001年 | 496篇 |
2000年 | 443篇 |
1999年 | 448篇 |
1998年 | 356篇 |
1997年 | 290篇 |
1996年 | 290篇 |
1995年 | 253篇 |
1994年 | 243篇 |
1993年 | 207篇 |
1992年 | 199篇 |
1991年 | 181篇 |
1990年 | 149篇 |
1989年 | 133篇 |
1988年 | 83篇 |
1987年 | 62篇 |
1986年 | 58篇 |
1985年 | 57篇 |
1984年 | 35篇 |
1983年 | 31篇 |
1982年 | 25篇 |
1981年 | 13篇 |
1980年 | 11篇 |
1978年 | 13篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1975年 | 8篇 |
1974年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
A rigid supramolecular polymer was constructed in aqueous solution via cucurbit[8]uril(CB[8]) host recognition with a rigid monomer containing an azobenzene unit and two 4,4'-bipyridin-1-ium(BP)moieties in the two ends, which also exhibited photo-responsiveness owing to the photoinduced trans–cis isomerization of azobenzene group. 相似文献
63.
Analysis and pharmacokinetic study of polyphyllin H in beagle dog plasma after oral administration of Rhizoma Paridis Extracts by LC‐MS/MS 下载免费PDF全文
64.
Dr. Ling‐Yun Yang Dr. Xiao‐Bin Fu Dr. Tai‐Qiang Chen Prof. Li‐Kun Pan Dr. Peng Ji Prof. Ye‐Feng Yao Prof. Qun Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(17):6346-6349
Highly conductive, crystalline, polymer electrolytes, β‐cyclodextrin (β‐CD)–polyethylene oxide (PEO)/LiAsF6 and β‐CD–PEO/NaAsF6, were prepared through supramolecular self‐assembly of PEO, β‐CD, and LiAsF6/NaAsF6. The assembled β‐CDs form nanochannels in which the PEO/X+ (X=Li, Na) complexes are confined. The nanochannels provide a pathway for directional motion of the alkali metal ions and, at the same time, separate the cations and the anions by size exclusion. 相似文献
65.
66.
Preparation of coatings from a series of silicone/fluorine‐functionalized polyacrylates via electrophoretic deposition 下载免费PDF全文
Weiming Yao Zhengping Wang Xu Wu Bingbing Li Ximing Zhong Jing Lin Jingyuan Chen Yanghong Lai 《先进技术聚合物》2015,26(9):1148-1154
Silicone/fluorine‐functionalized polyacrylates were synthesized and subsequently used to prepare corrosion‐resistant transparent coatings via electrophoretic deposition. The coated tin plate with the functionalized polyacrylate had a gloss value higher than 95.0 GU and resisted rust after immersion in a 5 wt% NaCl solution for 10 days. In addition, these coatings remained adhered strongly to the tin plates even after they were bent. It is hoped that this work will provide useful experimental data and assist researchers with the design of applicable coatings with desirable properties. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
67.
In this paper, we study some properties of composition operators on Hilbert spaces of Dirichlet series, which include the Fredholmness, Hilbert-Schmidtness, spectra, cyclic and hypercyclic phenomenons, and also answer a norm question raised by Cowen and MacCluer. 相似文献
68.
69.
Xiaoxia Yang Hongyan Xie Zhiguang Xu Jiabing Feng Qiwei Fu Haidong Li Yongtang Jia 《Journal of polymer science. Part A, Polymer chemistry》2021,59(9):813-823
An efficient, atom-economic, oxygen-tolerant, and water-tolerant strategy has been established to synthesize cyano-rich polyesters. Four kinds of organic bases, 1,1,3,3-tetramethylguanidine (TMG), 4-dimethylaminopyridine, triethylamine, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) were explored for accelerating Michael addition polymerization of malononitrile and 1,4-butandiol diacrylate. TMG can promote the polymerization efficiently under mild conditions to quantitatively afford polyester with high-molecular weight and moderate polydispersity. The comparison of the kinetic studies of TMG and TBD reveals that TMG shows better catalytic performance, while the catalysis of TBD brings about oligomers in spite of the higher efficiency at early age of the polymerization. Moreover, other diacrylate compounds could also be quantitatively polymerized to afford polyesters with high molecular weight. When dimethacrylate is chose as the monomer, the polymerization becomes sluggish. All the afforded polyesters display programmable thermal and mechanical properties that are closely related to their chemical structures. 相似文献
70.
An N. Le Ruiqi Liang Xiaoyu Ji Xiaowei Fu Mingjiang Zhong 《Journal of polymer science. Part A, Polymer chemistry》2021,59(21):2571-2580
The random copolymerization of norbornene-functionalized macromonomers was explored as a method of synthesizing mixed-graft block copolymers (mGBCPs). The copolymerization kinetics of a model system of polystyrene (PS) and poly(lactic acid) (PLA) macromonomers was first analyzed, revealing a gradient composition of side chains along the mGBCP backbone. The phase separation behavior of mGBCPs with PS and PLA side chains of various backbone lengths and side chain molar ratios was investigated, and increasing the backbone length was found to stabilize the phase-separated nanostructures. The graft architecture was also demonstrated to improve the processability of the mGBCP, compared to a linear counterpart. Investigations of mGBCPs comprised of polydimethylsiloxane and poly(ethylene oxide) side chains exemplified the diverse self-assembled morphologies, including a Frank-Kasper A15 phase, that can be obtained with mGBCPs synthesized by random copolymerization of macromonomers. Lastly, a ternary mGBCP was synthesized by the copolymerization of three macromonomers. 相似文献