全文获取类型
收费全文 | 30243篇 |
免费 | 5228篇 |
国内免费 | 3905篇 |
专业分类
化学 | 16017篇 |
晶体学 | 301篇 |
力学 | 1358篇 |
综合类 | 303篇 |
数学 | 2671篇 |
物理学 | 8438篇 |
无线电 | 10288篇 |
出版年
2024年 | 61篇 |
2023年 | 617篇 |
2022年 | 858篇 |
2021年 | 1085篇 |
2020年 | 1217篇 |
2019年 | 1115篇 |
2018年 | 982篇 |
2017年 | 992篇 |
2016年 | 1283篇 |
2015年 | 1465篇 |
2014年 | 1764篇 |
2013年 | 2186篇 |
2012年 | 2635篇 |
2011年 | 2677篇 |
2010年 | 2062篇 |
2009年 | 2142篇 |
2008年 | 2229篇 |
2007年 | 1969篇 |
2006年 | 1865篇 |
2005年 | 1602篇 |
2004年 | 1235篇 |
2003年 | 1002篇 |
2002年 | 952篇 |
2001年 | 815篇 |
2000年 | 621篇 |
1999年 | 594篇 |
1998年 | 438篇 |
1997年 | 463篇 |
1996年 | 412篇 |
1995年 | 327篇 |
1994年 | 303篇 |
1993年 | 228篇 |
1992年 | 166篇 |
1991年 | 182篇 |
1990年 | 148篇 |
1989年 | 101篇 |
1988年 | 97篇 |
1987年 | 74篇 |
1986年 | 57篇 |
1985年 | 48篇 |
1984年 | 48篇 |
1983年 | 41篇 |
1982年 | 42篇 |
1981年 | 30篇 |
1980年 | 21篇 |
1979年 | 19篇 |
1978年 | 8篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1975年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
891.
892.
893.
Dandan Bu Yuying Wang Na Wu Wei Feng Donghui Wei Zhanxian Li Mingming Yu 《中国化学快报》2021,32(5):1799-1802
Based on 4-bromo-1,8-naphthalic anhydride, one novel ratiometric fluorescence H2S-probe (IDNA) was designed and synthesized. Further studies indicate that IDNA can sensitively recognize H2S (detection limit of 7 μmol/L) with good selectivity and anti-interference ability. In addition, IDNA has satisfactory photostability in HeLa cells, ability of mitochondrial co-localization, and can be utilized in fluorescence imaging of H2S. 相似文献
894.
Chemistry of Natural Compounds - Arugosin R (1), a new arugosin type metabolite, was isolated from Talaromyces flavus. Its structure was characterized by detailed analyses of IR, MS, 1D, and 2D NMR... 相似文献
895.
896.
Xian Tao Ke‐Cheng Shen Qing‐Yun Tang Meng Feng Jiang‐Tao Fang Yu‐Long Wang Ying‐Zhong Shen 《应用有机金属化学》2012,26(7):323-329
New N‐silver(I) acetylbenzamide complexes of type Ln?AgNC9H8O2 (L = PPh3; n = 1, 2a; n = 2, 2b; n = 3, 2c; L = P(OEt)3; n = 1, 2d; n = 2, 2e; n = 3, 2f) were prepared. These complexes were obtained in high yields and characterized by elemental analysis, 1H NMR, 13C{H} NMR, 31P{H} NMR and IR spectroscopy, respectively. The molecular structure of 2b has been determined by X‐ray single‐crystal analysis in which the silver atom is in a distorted tetrahedral geometry and crystallizes as cis–trans. New N‐silver(I) acetylbenzamide complexes have a four‐membered ring, which could influence their chemical and physical properties and modulate volatility. Metal organic chemical vapor deposition experiments were carried out successfully at 400°C and 450°C using 2e as precursor for the deposition of silver films, respectively. The high‐purity silver film obtained at 400°C is dense and homogeneous. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
897.
898.
Through a two-step vacuum-filtration process, WSe2 and MoS2 nanosheets were sequentially deposited onto a polymeric nanoporous support, forming WSe2/MoS2 bi-layered heterostructure. Highly rectified ion transport phenomenon is observed through the heterogeneous 2D layered membranes. 相似文献
899.
900.
Cangyi Chen Ping Tang Feng Qiu 《Journal of polymer science. Part A, Polymer chemistry》2014,52(24):1583-1599
Binary polymer brushes, including mixed homopolymer brushes and diblock copolymer brushes, are an attractive class of environmentally responsive nanostructured materials. Owing to microphase separation of the two chemically distinct components in the brush, multifaceted nanomaterials with functionalized and patterned surfaces can be obtained. This review summarizes recent progress on the theory and simulations related to binary polymer brushes grafted to flat, spherical, and cylindrical substrates, with a focus on patterned morphologies of multifaceted hairy nanoparticles, an intriguing class of hybrid nanostructured particles (e.g., nanospheres and nanorods). In particular, powerful field theory and particle-based simulations suitable for revealing novel structures on these patterned surfaces, including self-consistent field theory and dissipative particle dynamics simulations, are emphasized. The unsolved yet critical issues in this research field, such as dynamic response of binary polymer brushes to environmental stimuli and the hierarchical self-assembly of binary hairy nanoparticles, are briefly discussed. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1583–1599 相似文献