全文获取类型
收费全文 | 14423篇 |
免费 | 698篇 |
国内免费 | 63篇 |
专业分类
化学 | 10281篇 |
晶体学 | 48篇 |
力学 | 339篇 |
数学 | 2401篇 |
物理学 | 2115篇 |
出版年
2023年 | 96篇 |
2022年 | 127篇 |
2021年 | 206篇 |
2020年 | 311篇 |
2019年 | 324篇 |
2018年 | 160篇 |
2017年 | 185篇 |
2016年 | 470篇 |
2015年 | 518篇 |
2014年 | 525篇 |
2013年 | 712篇 |
2012年 | 963篇 |
2011年 | 983篇 |
2010年 | 610篇 |
2009年 | 539篇 |
2008年 | 800篇 |
2007年 | 764篇 |
2006年 | 706篇 |
2005年 | 680篇 |
2004年 | 534篇 |
2003年 | 453篇 |
2002年 | 426篇 |
2001年 | 212篇 |
2000年 | 190篇 |
1999年 | 176篇 |
1998年 | 177篇 |
1997年 | 179篇 |
1996年 | 154篇 |
1995年 | 122篇 |
1994年 | 115篇 |
1993年 | 126篇 |
1992年 | 98篇 |
1991年 | 110篇 |
1990年 | 96篇 |
1989年 | 104篇 |
1988年 | 89篇 |
1987年 | 66篇 |
1986年 | 68篇 |
1985年 | 92篇 |
1984年 | 84篇 |
1983年 | 77篇 |
1982年 | 93篇 |
1981年 | 104篇 |
1980年 | 88篇 |
1979年 | 92篇 |
1978年 | 86篇 |
1977年 | 71篇 |
1976年 | 75篇 |
1975年 | 74篇 |
1973年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 397 毫秒
991.
992.
993.
994.
995.
996.
997.
998.
Tkachenko AG Xie H Coleman D Glomm W Ryan J Anderson MF Franzen S Feldheim DL 《Journal of the American Chemical Society》2003,125(16):4700-4701
The ability of peptide-modified gold nanoparticles to target the nucleus of HepG2 cells was explored. Five peptide/nanoparticle complexes were investigated, particles modified with (1) the nuclear localization signal (NLS) from the SV 40 virus; (2) the adenovirus NLS; (3) the adenovirus receptor-mediated endocytosis (RME) peptide; (4) one long peptide containing the adenovirus RME and NLS; and (5) the adenovirus RME and NLS peptides attached to the nanoparticle as separate pieces. Gold nanoparticles were used because they are easy to identify using video-enhanced color differential interference contrast microscopy, and they are excellent scaffolds from which to build multifunctional nuclear targeting vectors. For example, particles modified solely with NLS peptides were not able to target the nucleus of HepG2 cells from outside the plasma membrane, because they either could not enter the cell or were trapped in endosomes. The combination of NLS/RME particles (4) and (5) did reach the nucleus; however, nuclear targeting was more efficient when the two signals were attached to nanoparticles as separate short pieces versus one long peptide. These studies highlight the challenges associated with nuclear targeting and the potential advantages of designing multifunctional nanostructured materials as tools for intracellular diagnostics and therapeutic delivery. 相似文献
999.
McGuinness DS Wasserscheid P Keim W Morgan D Dixon JT Bollmann A Maumela H Hess F Englert U 《Journal of the American Chemical Society》2003,125(18):5272-5273
Cr(III) complexes of tridentate SNS ligands have been prepared and evaluated as catalysts for ethylene trimerization, with several giving very high activity and excellent selectivity toward 1-hexene when activated with methylaluminoxane. The new complexes illustrate the potential of sulfur-based ligands on early transition metals for catalysis. 相似文献
1000.
Chiappe C Detert H Lenoir D Pomelli CS Ruasse MF 《Journal of the American Chemical Society》2003,125(10):2864-2865
Weakly bound molecular complexes play an important role in chemistry, physics, and biodisciplines. The preequilibrium pi-complexes of various alkenes with bromine have been examined quantitatively, and a direct relationship between association constants (KF) of these pi-complexes and polarizability of the olefins was found. The stability of the Br2-olefin pi complexes is affected by both the donor ionization potential and the polarizability of the olefin, and an equation able to take into account both effects is proposed. 相似文献