全文获取类型
收费全文 | 3708篇 |
免费 | 135篇 |
专业分类
化学 | 2186篇 |
晶体学 | 28篇 |
力学 | 66篇 |
数学 | 812篇 |
物理学 | 751篇 |
出版年
2021年 | 45篇 |
2020年 | 73篇 |
2019年 | 61篇 |
2018年 | 68篇 |
2017年 | 90篇 |
2016年 | 175篇 |
2015年 | 156篇 |
2014年 | 148篇 |
2013年 | 265篇 |
2012年 | 184篇 |
2011年 | 257篇 |
2010年 | 167篇 |
2009年 | 119篇 |
2008年 | 134篇 |
2007年 | 98篇 |
2006年 | 87篇 |
2005年 | 106篇 |
2004年 | 129篇 |
2003年 | 83篇 |
2002年 | 34篇 |
2001年 | 31篇 |
2000年 | 34篇 |
1999年 | 26篇 |
1998年 | 32篇 |
1997年 | 27篇 |
1996年 | 30篇 |
1995年 | 28篇 |
1990年 | 30篇 |
1989年 | 24篇 |
1988年 | 25篇 |
1985年 | 34篇 |
1984年 | 37篇 |
1983年 | 30篇 |
1982年 | 29篇 |
1981年 | 25篇 |
1978年 | 30篇 |
1977年 | 24篇 |
1976年 | 30篇 |
1975年 | 25篇 |
1973年 | 27篇 |
1968年 | 40篇 |
1965年 | 43篇 |
1964年 | 45篇 |
1963年 | 27篇 |
1962年 | 38篇 |
1961年 | 36篇 |
1960年 | 32篇 |
1959年 | 29篇 |
1958年 | 26篇 |
1957年 | 25篇 |
排序方式: 共有3843条查询结果,搜索用时 15 毫秒
31.
Jiří Hošek 《Czechoslovak Journal of Physics》1991,41(11):1037-1041
We demonstrate within the Ginzburg-Landau model of a confining medium that the surface energy associated with the interface between the normal and the confining phases can be negative, and briefly discuss some consequences of this fact.Dedicated to the memory of M. Gmitro.This work was done at the Niels Bohr Institute Copenhagen, and put into its final form at the Institute of Theoretical Physics, of University of Regensburg. I thank both institutes for their generous hospitality and Professors Poul Olesen and Wolfram Weise for discussions. 相似文献
32.
J. Hála M. Vácha J. Dian F. Adamec M. Ambrož R. Tesař 《Czechoslovak Journal of Physics》1991,41(4):373-380
The persistent spectral hole burning technique has been applied to free base and central metal tetraphenylporphyrins with different substituents. The upper limits of the singlet-singlet homogeneous widths determined from the observed persistent holes have been correlated with the fluorescence lifetimes at low temperatures. Hole burning kinetics and mechanisms of both free base and central metal pigments are discussed.The authors would like to thank dr. V. Král and P. Pancoska for supplying the tetraphenylporphyrins, prof. K. Vacek and I. Pelant for stimulating discussions. 相似文献
33.
Jiři Votinský Jaroslava Kalousová Ludvík Beneš 《Journal of inclusion phenomena and macrocyclic chemistry》1992,14(1):19-24
The paper deals with the relations between host lattices and guest molecules. Several types of interaction of the guest molecules and the host material are explained and some conclusions are made about the arrangement of various guest molecules in the van der Waals' gap. 相似文献
34.
The paper brings a preliminary submicro-level analysis of the temperature increase and acoustice mission caused by rnicrocrack propagation. The analysis is based on molecular dynamic simulations. 相似文献
35.
This review of ion-selective electrodes is arranged in the same way as Parts I and II. The continuous growth of the whole subject should be noted. Theory has particularly progressed through mechanistic studies. Among new types of electrodes, ISFET systems have become important. Among new applications of both solid and liquid membrane electrodes, the fluoride electrode still predominates, closely followed by potassium electrodes. In the field of biological and medical applications, the steady growth is significant. More than 800 papers published between mid-1976 and the end of 1978 are mentioned in the review. 相似文献
36.
B. Bareika R. Danielius G. Dikchius R. Gadonas A. Piskarskas V. Sirutkaitis R. L. Fork C. V. Shank R. Yen C. Hirlimann W. J. Tomlinson P. Hříbek V. Kubeček M. Vrbová I. S. Ruddock R. Illingworth L. Reekie D. P. Weitekamp K. Duppen D. A. Wiersma 《Applied physics. B, Lasers and optics》1982,29(3):176-179
37.
Homogeneity and structure of organically modified polysiloxane networks prepared by sol-gel co-condensation, as well as location and nature of water molecules and silanol groups were studied by 1D and 2D solid-state NMR. 1H–29Si and 1H–1H interatomic distances were estimated from variable contact-time CP/MAS experiments, 1H NMR chemical shifts and off-resonance WISE NMR. A structure model of these networks is proposed and discussed. The fraction of proton-inaccessible units Q4 in the networks decreases with increasing amounts of dimethylsiloxane (D) and methylsiloxane (T) units. In contrast to systems prepared by co-condensation of tetraethoxysilane (TEOS) with dimethyl(diethoxy)silane (DMDEOS), proton-inaccessible units form essential fraction in networks prepared by co-condensation of TEOS with methyl(triethoxy)silane (MTEOS). The proton-accessible part of the networks with high O/Si ratios is nano-heterogeneous phase, which is composed of water containing Q
i
particles separated by copolymer domains. The overall homogeneity and uniformity of binding sites around silanol groups increases by co-condensation TEOS with DMDEOS or MTEOS, while the amount of physisorbed water as well as the hydrogen bond strength decreases, as compared with neat silica gel prepared by polycondensation of TEOS. 相似文献
38.
YAG : Nd grown under 98% Ar 2% H2 protective atmosphere free of nitrogen or hydrocarbons showed after UV irradiation broad absorption peaked at 1·9×104 cm–1 which disappeared relatively slowly at room temperature. It was more intensive in oxygen treated samples than in those annealed in hydrogsn. Transient absorption suppresses laser output by the increase of absorption at 0·94×104 cm–1 (1064 nm) and, particularly in CW mode, by the anomalous rod deformation. YAG : Nd containing Fe ions (2·10–4 wt%) showed no transient absorption. 相似文献
39.
P. Franc J. Křemének Š. Piskoř W. Schäferlingová 《Czechoslovak Journal of Physics》1979,29(10):1084-1090
A multi-angle magnetic spectrograph for recording spectra of charged particles emitted in nuclear reactions has been built. The apparatus and the beam transport system are described and their parameters are discussed. 相似文献
40.
Attempts to construct structural models of glassy CdGeAs2 are described. Microcrystal models with normal and appropriately distorted crystallites gave poor fits with the experiment. Relaxed random network models, in which force constants and equilibrium distances and angles obtained by an energy relaxation of the crystal were used to minimize their free energy, provided excellent agreement with experiment if only even-numbered rings and, therefore, no wrong bonds were allowed to form. 相似文献