全文获取类型
收费全文 | 2341篇 |
免费 | 58篇 |
国内免费 | 17篇 |
专业分类
化学 | 1685篇 |
晶体学 | 34篇 |
力学 | 23篇 |
数学 | 149篇 |
物理学 | 525篇 |
出版年
2023年 | 11篇 |
2022年 | 9篇 |
2021年 | 21篇 |
2020年 | 23篇 |
2019年 | 34篇 |
2018年 | 24篇 |
2017年 | 16篇 |
2016年 | 32篇 |
2015年 | 34篇 |
2014年 | 68篇 |
2013年 | 93篇 |
2012年 | 132篇 |
2011年 | 147篇 |
2010年 | 69篇 |
2009年 | 91篇 |
2008年 | 116篇 |
2007年 | 141篇 |
2006年 | 133篇 |
2005年 | 131篇 |
2004年 | 102篇 |
2003年 | 94篇 |
2002年 | 94篇 |
2001年 | 68篇 |
2000年 | 44篇 |
1999年 | 17篇 |
1998年 | 27篇 |
1997年 | 31篇 |
1996年 | 34篇 |
1995年 | 17篇 |
1994年 | 20篇 |
1993年 | 27篇 |
1992年 | 35篇 |
1991年 | 28篇 |
1990年 | 38篇 |
1989年 | 32篇 |
1988年 | 36篇 |
1987年 | 36篇 |
1986年 | 36篇 |
1985年 | 37篇 |
1984年 | 31篇 |
1983年 | 18篇 |
1982年 | 21篇 |
1981年 | 15篇 |
1980年 | 16篇 |
1979年 | 22篇 |
1978年 | 14篇 |
1977年 | 18篇 |
1975年 | 19篇 |
1974年 | 22篇 |
1973年 | 8篇 |
排序方式: 共有2416条查询结果,搜索用时 15 毫秒
71.
72.
73.
Allen WH Bond IA Budding E Conway MJ Daniel A Fenton KB Fujii H Fujii Z Hayashida N Hibino K Honda M Humble JE Kabe S Kasahara K Kifune T Lythe GD Masaike A Matsubara Y Mitsui K Miura Y Mori M Muraki Y Nagano M Nakamura T Nishizawa M Morris PM Ogio S Saito T Sakata M Sato H Shimizu HM Spencer M Storey JR Tanimori T Teshima M Torii S Wadsworth A Watase Y Woodhams MD Yamamoto Y Yock PC Yuda T 《Physical review D: Particles and fields》1993,48(2):466-478
74.
Katayama H Satoh K Takeuchi M Deguchi-Tawarada M Oda Y Nagasu T 《Rapid communications in mass spectrometry : RCM》2003,17(10):1071-1078
Improvement of in-gel digestion efficiency is highly desirable for one- or two-dimensional gel electrophoretic separation and mass spectrometric (MS) analysis in proteomics, because the resultant increases in sequence coverage and MS signal intensity lead to higher confidence in protein identification. Here an optimized in-gel digestion system, in combination with thin-gel separation and negative staining in a high-throughput format using 96-well plates, is described. The combination of negative staining and protein separation on a 0.9 mm thick gel showed a clear improvement in in-gel digestion efficiency in comparison with the more typical protocols such as the combination of silver staining and a 1.0 mm gel. In addition, the use of 96-well plates to increase throughput did not decrease the efficiency of this strategy when the stirring of the gel pieces in processes such as destaining, washing, gel-shrinking and peptide extraction was performed by sonication instead of shaking the plates. This procedure was optimized and applied to identify proteins of the postsynaptic density fraction; 105 proteins were identified after SDS-PAGE separation. 相似文献
75.
Several beta-secretase inhibitors were designed based on hydroxyethylamine dipeptide isostere (HDI) structures and were synthesized by a methodology using the aza-Payne rearragement and O,N-acyl transfer reactions to study their structure-activity relationships. Among these pseudopeptides, effective compounds were developed as the first beta-secretase inhibitors containing the HDI transition state mimic with potent enzyme inhibitory activity (IC50 < 100 nM). 相似文献
76.
The common synthetic intermediate of a potent and promising anticancer agent, fostriecin, was synthesized using a unique method that combines four catalytic asymmetric reactions as shown above. 相似文献
77.
78.
Aihara H Alston-Garnjost M Bakken JA Barbaro-Galtieri A Barnes AV Barnett BA Bengtsson H Blumenfeld BJ Bross AD Buchanan CD Chamberlain O Chien C Clark AR Cordier A Dahl OI Day CT Derby KA Eberhard PH Fancher DL Fujii H Fujii T Gabioud B Gary JW Gorn W Hadley NJ Hauptman JM Hofmann W Huth JE Hylen J Kamae T Kaye HS Kenney RW Kerth LT Koda RI Kofler RR Kwong KK Layter JG Lindsey CS Loken SC Lu X Lynch GR Madansky L Madaras RJ Maruyama K Marx JN Matthews JA Melnikoff SO Moses W Nemethy P 《Physical review letters》1985,54(4):270-273
79.
Tsutomu Kagiya Masatsugu Izu Masakazu Hatta Takehisa Matsuda Kenichi Fukui 《Journal of polymer science. Part A, Polymer chemistry》1967,5(5):1129-1135
N,N′-Dipropionylethylenediamine was synthesized by the ring-opening addition reaction of 2-ethyl-2-imidazoline with propionic acid at 220°C. By applying this reaction to polymerization, polyamides were synthesized by the ring-opening polyaddition reaction at 220°C. of 1,4-bis(imidazoline-2-yl)butane with adipic acid, succinic acid, sebacic acid, and terephthalic acid. The reaction product of 1,4-bis(imidazoline-2-yl)butane with adipic acid, which was proposed to be nylon 26, was compared with an authentic sample of nylon 26 and shown to possess a very similar infrared spectrum and melting point. 相似文献
80.