全文获取类型
收费全文 | 889篇 |
免费 | 8篇 |
国内免费 | 3篇 |
专业分类
化学 | 632篇 |
晶体学 | 9篇 |
力学 | 23篇 |
数学 | 86篇 |
物理学 | 150篇 |
出版年
2023年 | 3篇 |
2022年 | 11篇 |
2021年 | 25篇 |
2020年 | 12篇 |
2019年 | 12篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 24篇 |
2015年 | 11篇 |
2014年 | 9篇 |
2013年 | 62篇 |
2012年 | 41篇 |
2011年 | 39篇 |
2010年 | 40篇 |
2009年 | 37篇 |
2008年 | 58篇 |
2007年 | 53篇 |
2006年 | 45篇 |
2005年 | 50篇 |
2004年 | 41篇 |
2003年 | 29篇 |
2002年 | 49篇 |
2001年 | 12篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 12篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 11篇 |
1993年 | 13篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 11篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1973年 | 4篇 |
排序方式: 共有900条查询结果,搜索用时 15 毫秒
131.
132.
133.
Claudio Bianchini Andrea Meli Annabella Orlandini Giancarlo Scapacci 《Journal of organometallic chemistry》1981,215(3):C59-C62
The reaction of the zwitterion Et3PCS2, with iron (II) tetrafluoroborate in the presence of 1,2-bis(diethylphosphino) ethane (depe) and NaBPh4 gave the unusual complex [(depe)2Fe(S2CPEt3)] (BPh4)2 (I), whose structure has been determined by X-ray analysis. A dithioformatoiron(II) complex was made by treating I with NaBH4. 相似文献
134.
Alessandro Dondoni Tiziano DallOcco Giancarlo Fantin Marco Fogagnolo Alessandro Medici 《Tetrahedron letters》1984,25(33):3633-3636
N-Ethoxycarbonylthiazolium chloride generated from 1,3-thiazole and ethyl chloroformate, treated with lithium carbanions of esters, Grignard reagents, silyl enol ethers and esters, undergo nucleophilic addition at C2 affording the corresponding 2-substituted N-ethoxycarbonylthiazolines. 相似文献
135.
136.
Renato Dogliotti Angelo Luvison Giancarlo Pirani 《Optical and Quantum Electronics》1979,11(6):541-550
The problem of pulse shaping and sensitivity to timing errors in optical fibre data communication is considered. The performance of the overall transmission system is the average probability of error, which is computed for intersymbol interference, thermal noise, and shot noise in avalanche photodiodes. An analysis of the immunity to small sampling errors of various Nyquist pulses indicates useful design criteria. 相似文献
137.
Giulio Ceccarelli Giancarlo Berti Giorgio Lippi Bruno Macchia 《Magnetic resonance in chemistry : MRC》1970,2(4):379-388
NMR spectra of several styrene, stilbene and stilbazole oxides have been determined, and chemical shifts and coupling constants have been correlated with cis-and trans-configurations. Assignments have been made for all protons, and double resonance technique and 13C? H coupling constants have been used in some particular cases. An explanation is proposed for the observation that chemical shifts of oxirane protons are higher for cis than for trans isomers. 相似文献
138.
Cationic nickel catalysts with monodentate phosphoramidites and Wilke's azaphospholene as ligands are highly regio- and enantioselective catalysts for the cycloisomerisation of diethyl diallylmalonate. 相似文献
139.
140.
Ugo Abbondanno Ferruccio Demanins Maria Rosa Malisan Giancarlo Nardelli 《Nuclear Physics A》1978,305(1):117-143
The de-excitation gammas following the inelastic scattering of neutrons from 75As have been studied for incident neutron energies from 1300 to 2800 keV in steps of 100 keV. The energy levels and the branching ratios of their decays have been deduced from excitation function measurements: 58 energy levels have been found in the excitation energy region below 2.8 MeV, twelve of which are reported for the first time in this work. The experimental excitation functions and angular distributions have been compared with the theoretical predictions based on the statistical theory of the compound nucleus. Spin and parity assignments for the levels and multipolarities for the decays are proposed for excitation energies of levels up to 2300 keV. 相似文献