全文获取类型
收费全文 | 3219篇 |
免费 | 77篇 |
国内免费 | 10篇 |
专业分类
化学 | 2468篇 |
晶体学 | 67篇 |
力学 | 51篇 |
数学 | 136篇 |
物理学 | 584篇 |
出版年
2023年 | 14篇 |
2021年 | 26篇 |
2020年 | 32篇 |
2019年 | 38篇 |
2018年 | 25篇 |
2017年 | 18篇 |
2016年 | 55篇 |
2015年 | 62篇 |
2014年 | 63篇 |
2013年 | 149篇 |
2012年 | 147篇 |
2011年 | 163篇 |
2010年 | 96篇 |
2009年 | 98篇 |
2008年 | 154篇 |
2007年 | 193篇 |
2006年 | 199篇 |
2005年 | 155篇 |
2004年 | 170篇 |
2003年 | 143篇 |
2002年 | 139篇 |
2001年 | 91篇 |
2000年 | 80篇 |
1999年 | 47篇 |
1998年 | 39篇 |
1997年 | 27篇 |
1996年 | 52篇 |
1995年 | 37篇 |
1994年 | 45篇 |
1993年 | 41篇 |
1992年 | 73篇 |
1991年 | 35篇 |
1990年 | 31篇 |
1989年 | 28篇 |
1988年 | 33篇 |
1987年 | 38篇 |
1986年 | 37篇 |
1985年 | 43篇 |
1984年 | 49篇 |
1983年 | 23篇 |
1982年 | 26篇 |
1981年 | 29篇 |
1980年 | 23篇 |
1979年 | 36篇 |
1978年 | 32篇 |
1977年 | 22篇 |
1976年 | 23篇 |
1975年 | 15篇 |
1974年 | 23篇 |
1973年 | 17篇 |
排序方式: 共有3306条查询结果,搜索用时 31 毫秒
991.
S. Suzuki Y. Inoue I. Ando R. Chujo K. Seto K. Hoshino 《Colloid and polymer science》1977,255(6):618-618
Ohne Zusammenfassung 相似文献
992.
The emission and excitation spectra of P-doped Cd1?xMgxTe (x ? 0.45) mixed crystals have been measured over the temperature range of 300 ~ 4.2 K to reinvestigate the photoluminescence process of two broad emission bands; the 690 nm band of the as- grown crystals and the 610 nm band of the annealed crystal. The excitation spectrum of each band has a characteristic peak at 550 nm near the absorption edge of this crystal. Together with the data of the decay characteristic and the halfwidth of each band, we discuss the difference in the recombination process when the crystal is excited under two different radiation at 365 and 570 nm (close to the 550 nm radiation). It is concluded that both emission bands arise from donor-acceptor pairs and a localized center or self- activated center; the associated pair is VCd-interstitial P in the as-grown and VTe ? PTe in the annealed crystal. 相似文献
993.
994.
995.
Summary Response functions for underground muons are obtained by solving numerically the equations of hadronic cascades in the atmosphere,
by assuming Feynman scaling for hadronic interactions over the whole energy region. For practical use of the response functions
in cosmic-ray modulation study, calculations are made for various combinations of parameters such as zenith angle, atmospheric
depth and muon threshold energy. The present response functions are consistent with cosmic-ray measurements and can be well
utilized for the study on the cosmic-ray modulation.
Riassunto Si ottengono funzioni di risposta per muoni sotterranei risolvendo numericamente le equazioni per le cascate adroniche nell'atmosfera, assumendo lo scaling di Feynman per interazioni adroniche nell'intera regione di energia. Per l'uso pratico di funzioni di risposta nello studio di modulazione dei raggi cosmici, si fanno calcoli per varie combicazioni di parametri come l'angolo di zenit, la profondità atmosferica e l'energia muonica di soglia. Le attuali funzioni di risposta sono coerenti con le misurazioni dei raggi cosmici e possono essere bene utilizzate per lo studio della modulazione dei raggi cosmici.相似文献
996.
Atsushi Inoue 《Reports on Mathematical Physics》1978,13(1):25-35
The primary purpose of this paper is to study unbounded operator algebras called standard EW#-algebras which are generalizations of standard von Neumann algebras to the unbounded case.The first part is an investigation of the weak, σ-weak, strong and σ-strong topologies on a standard EW#-algebra. It is showed that the weak and σ-weak topologies on a standard EW#-algebra coincide.The second part is a study of a locally convex topology called ∞Lω2-topology on a standard EW#-algebra U. It is proved that U is a GB1-algebra under the topology.The third part is an investigation of isomorphisms of standard EW#-algebras. It is showed that if standard EW#-algebras U and B are isomorphic then U and B are spatially isomorphic. 相似文献
997.
Ohne Zusammenfassung 相似文献
998.
999.
Photochemical behaviour of sodium allylphenoxides 1a–3a was compared with that of corresponding neutral allylphenols 1b–3b, and a striking difference was found in reactivity as well as in course of the reaction. Remarkably higher photoreactivity of allylphenoxide anions, especially that of o-allylphenoxide 1a, is ascribed to the efficiency of electron transfer. The characteristic reaction products derived only from the anions were as follows: (a) intramolecular cyclization products, indanols 9, from 2a, (b) rearranged reduction products 10 from both 2a and 3a, and (c) degradative methanol-adduct 11 from 3a. Methanol-adducts 7 and photo-reduction products 6 were formed in either case. In addition cyclization products with the participation of O atom, 4 and 5, were obtained from 1a and 1b. Occurrence of the di-π-methane rearrangement was restricted to the reaction of neutral species 1b–3b. A mechanism based on electron transfer in the excited state is suggested for the course of the photoreaction. 相似文献
1000.