全文获取类型
收费全文 | 3462篇 |
免费 | 90篇 |
国内免费 | 13篇 |
专业分类
化学 | 2794篇 |
晶体学 | 41篇 |
力学 | 28篇 |
数学 | 65篇 |
物理学 | 637篇 |
出版年
2022年 | 22篇 |
2021年 | 30篇 |
2020年 | 28篇 |
2019年 | 37篇 |
2018年 | 21篇 |
2017年 | 32篇 |
2016年 | 55篇 |
2015年 | 52篇 |
2014年 | 77篇 |
2013年 | 129篇 |
2012年 | 193篇 |
2011年 | 234篇 |
2010年 | 105篇 |
2009年 | 129篇 |
2008年 | 204篇 |
2007年 | 208篇 |
2006年 | 194篇 |
2005年 | 212篇 |
2004年 | 183篇 |
2003年 | 161篇 |
2002年 | 138篇 |
2001年 | 105篇 |
2000年 | 81篇 |
1999年 | 70篇 |
1998年 | 39篇 |
1997年 | 41篇 |
1996年 | 34篇 |
1995年 | 36篇 |
1994年 | 31篇 |
1993年 | 34篇 |
1992年 | 43篇 |
1991年 | 32篇 |
1990年 | 39篇 |
1989年 | 28篇 |
1988年 | 18篇 |
1987年 | 36篇 |
1986年 | 19篇 |
1985年 | 35篇 |
1984年 | 35篇 |
1983年 | 21篇 |
1982年 | 34篇 |
1981年 | 32篇 |
1980年 | 24篇 |
1979年 | 42篇 |
1978年 | 23篇 |
1977年 | 21篇 |
1976年 | 17篇 |
1975年 | 17篇 |
1974年 | 19篇 |
1973年 | 15篇 |
排序方式: 共有3565条查询结果,搜索用时 15 毫秒
61.
Kondo F Saito H Hayashi R Onda H Kobayashi S Matsumoto M Suzuki M Ito Y Oka H Nakanishi T Shimizu A 《The Analyst》2003,128(11):1360-1364
We developed a rapid and reliable identification method for Shiga toxins in Shiga toxin-producing Escherichia coli (STEC) using immunoprecipitation and high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS). Polyclonal antisera specific for Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2) were raised in rabbits so as to be used for the immunoprecipitation. The immunoprecipitaion was carried out by mixing sample solutions with 50 microl each of the antisera to Stx1 and Stx2 followed by allowing the mixed solutions to stand for 30 min. The quantity required to obtain the immunoprecipitate was more than 0.5 microg of Shiga toxins. HPLC-ESI-MS analysis of the resulting immunoprecipitates provided accurate molecular weight information on Shiga toxins, leading to direct evidence for the presence of these toxins. It requires at most two days to perform our procedure from toxin extraction to measurement of HPLC-ESI-MS whereas the previous method using isolation procedures required about two weeks to complete. The usefulness of the present method has been demonstrated by identifying Stx1, Stx2 and a variant of Stx2 (Stx2e) in the immunoprecipitates prepared from STEC strains. 相似文献
62.
Eietsu Hasegawa Shinya Takizawa Akira Yamaguchi Naoki Chiba Hiroshi Ikeda 《Tetrahedron》2006,62(27):6581-6588
Photoinduced electron-transfer reactions of several ketone substrates were studied to evaluate the utilities of 1,6-bis(dimethylamino)pyrene (BDMAP), 1,6-dimethoxypyrene (DMP), 9,10-bis(dimethylamino)anthracene (BDMAA), and 9,10-dimethoxyanthracene (DMA) as electron-donating sensitizers cooperating with 2-aryl-1,3-dimethylbenzimidazolines. BDMAP and DMP generally led higher conversion of ketones and better yield of reduction products compared to BDMAA and DMA. 相似文献
63.
Masanori Yamaguchi Kaoru Kojima Ikuko Kakizaki Keiichi Takagaki 《Tetrahedron letters》2006,47(42):7455-7458
Efficient constructions of two types of neo-proteoglycan are described. Enzymatically prepared alkyne containing chondroitin 6-sulfate chains and chemically synthesized azido group having compounds are linked by utilizing the copper(I) catalyzed 1,3-dipolar cycloaddition. 相似文献
64.
Phenols are ethynylated at the ortho position with silylated chloroethyne in the presence of a catalytic amount of GaCl3 and lithium phenoxide. The lithium salt is essential for the catalysis, and addition of 2,6-di(tert-butyl)-4-methylpyridine inhibits desilylation and hydration of the products. The reaction can be applied to various substituted phenols giving the ortho-ethynylated products in high yields, and the turnover numbers based on GaCl3 are between 8 and 10. The reaction mechanism involves addition of in situ formed phenoxygallium to the haloethyne followed by the elimination of GaCl3. 相似文献
65.
66.
H Moriya C Moriwaki S Akimoto K Yamaguchi M Iwadare 《Chemical & pharmaceutical bulletin》1967,15(11):1662-1668
67.
68.
69.
70.