全文获取类型
收费全文 | 2555篇 |
免费 | 80篇 |
国内免费 | 16篇 |
专业分类
化学 | 1586篇 |
晶体学 | 16篇 |
力学 | 44篇 |
数学 | 480篇 |
物理学 | 367篇 |
无线电 | 158篇 |
出版年
2022年 | 24篇 |
2021年 | 34篇 |
2020年 | 26篇 |
2019年 | 36篇 |
2018年 | 24篇 |
2017年 | 29篇 |
2016年 | 40篇 |
2015年 | 33篇 |
2014年 | 48篇 |
2013年 | 112篇 |
2012年 | 87篇 |
2011年 | 138篇 |
2010年 | 82篇 |
2009年 | 70篇 |
2008年 | 120篇 |
2007年 | 105篇 |
2006年 | 113篇 |
2005年 | 113篇 |
2004年 | 119篇 |
2003年 | 105篇 |
2002年 | 91篇 |
2001年 | 24篇 |
2000年 | 33篇 |
1999年 | 27篇 |
1997年 | 21篇 |
1996年 | 55篇 |
1994年 | 30篇 |
1993年 | 23篇 |
1992年 | 27篇 |
1991年 | 25篇 |
1990年 | 31篇 |
1989年 | 23篇 |
1988年 | 24篇 |
1987年 | 22篇 |
1986年 | 25篇 |
1985年 | 43篇 |
1984年 | 36篇 |
1983年 | 31篇 |
1982年 | 33篇 |
1981年 | 32篇 |
1980年 | 34篇 |
1979年 | 27篇 |
1978年 | 35篇 |
1977年 | 36篇 |
1976年 | 23篇 |
1975年 | 32篇 |
1974年 | 37篇 |
1973年 | 30篇 |
1970年 | 20篇 |
1968年 | 19篇 |
排序方式: 共有2651条查询结果,搜索用时 15 毫秒
141.
El Oualid F van den Elst H Leroy IM Pieterman E Cohen LH Burm BE Overkleeft HS van der Marel GA Overhand M 《Journal of combinatorial chemistry》2005,7(5):703-713
A combinatorial synthesis of oligopeptide analogues and their evaluation as protein:geranylgeranyl transferase inhibitors is presented. The combinatorial strategy is based on the random mutation, in each new generation, of one of any of the four amino acid building blocks of which the most effective compounds of the previous generation are assembled. In this way, a progressive improvement of the average inhibitory activity was observed until the fifth generation. The most active inhibitors were found to inhibit PGGT-1 in the low micromolar range (IC(50): 3.8-8.1 microM). 相似文献
142.
Auerbach LB Burman RL Caldwell DO Church ED Cochran AK Donahue JB Fazely AR Garvey GT Gunasingha RM Imlay RL Kahrimanis G Louis WC Majkic R Malik A McIlhany KL Metcalf WJ Mills GB Rupnik D Sandberg VD Smith D Somodi RF Stancu I Strossman WD Sung M Tayloe R VanDalen GJ Vernon W Wadia N White DH Yellin S Yi H;LSND Collaboration 《Physical review letters》2004,92(9):091801
We observe a net beam excess of 8.7+/-6.3(stat)+/-2.4(syst) events, above 160 MeV, resulting from the charged-current reaction of nu(micro) and/or nu;(mu) on C and H in the LSND detector. No beam-related muon background is expected in this energy regime. Within an analysis framework of pi(0)-->nu(mu)nu;(mu), we set a direct upper limit for this branching ratio of Gamma(pi(0)-->nu(mu)nu;(mu))/Gamma(pi(0)-->all)<1.6 x 10(-6) at 90% confidence level. 相似文献
143.
144.
145.
Louis?Dupaigne Augusto?C.?Ponceaugponce@math.rutgers.edu" title="ponce@ann.jussieu.fr augponce@math.rutgers.edu" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author 《Selecta Mathematica, New Series》2004,10(3):341-358
We present several extensions of the Brezis–Lions Lemma on removable singularities. We also give a positive answer to a question raised by H. Brezis and M. Marcus about an inverse maximum principle for the Laplacian. 相似文献
146.
This review consolidates biological activity data reported for pyridoacridine 1 molecules in the literature from 1983-2003 into several tables with brief discussions of assays used and results obtained. This review summarizes recent progress in structure activity relationships for analogues of amphimedine 2 and ascididemin 3 classes of pyridoacridines and correlates reported molecular mechanisms of action with biological activities. 相似文献
147.
148.
Palacios JJ Pérez-Jiménez AJ Louis E SanFabián E Vergés JA 《Physical review letters》2003,90(10):106801
We present first-principles calculations of phase coherent electron transport in a carbon nanotube (CNT) with realistic contacts. We focus on the zero-bias response of open metallic CNT's considering two archetypal contact geometries (end and side) and three commonly used metals as electrodes (Al, Au, and Ti). Our ab initio electrical transport calculations make, for the first time, quantitative predictions on the contact transparency and the transport properties of finite metallic CNT's. Al and Au turn out to make poor contacts while Ti is the best option of the three. 相似文献
149.
Hawthorn DG Hill RW Proust C Ronning F Sutherland M Boaknin E Lupien C Tanatar MA Paglione J Wakimoto S Zhang H Taillefer L Kimura T Nohara M Takagi H Hussey NE 《Physical review letters》2003,90(19):197004
The transport of heat and charge in cuprates was measured in single crystals of La(2-x)Sr(x)CuO(4+delta) (LSCO) across the doping phase diagram at low temperatures. In underdoped LSCO, the thermal conductivity is found to decrease with increasing magnetic field in the T-->0 limit, in striking contrast to the increase observed in all superconductors, including cuprates at higher doping. In heavily underdoped LSCO, where superconductivity can be entirely suppressed with an applied magnetic field, we show that a novel thermal metal-to-insulator transition takes place upon going from the superconducting state to the field-induced normal state. 相似文献
150.
Hegedus LS Greenberg MM Wendling JJ Bullock JP 《The Journal of organic chemistry》2003,68(11):4179-4188
Several dioxocyclams containing quinoxaline moieties, as well as their nickel(II) complexes were synthesized and studied for their ability to bind and oxidatively cleave DNA. Although no evidence for binding by intercalation was found, the ability of the Ni(II) complexes to cleave DNA in the presence of Oxone was strongly dependent on both the nature and the spatial orientation of the quinoxaline moieties, suggesting at least transient association of these complexes with DNA. 相似文献