全文获取类型
收费全文 | 205997篇 |
免费 | 2014篇 |
国内免费 | 535篇 |
专业分类
化学 | 112998篇 |
晶体学 | 3677篇 |
力学 | 8197篇 |
综合类 | 11篇 |
数学 | 19836篇 |
物理学 | 63827篇 |
出版年
2020年 | 1754篇 |
2019年 | 1940篇 |
2018年 | 2274篇 |
2017年 | 2377篇 |
2016年 | 3587篇 |
2015年 | 2244篇 |
2014年 | 3610篇 |
2013年 | 9287篇 |
2012年 | 6625篇 |
2011年 | 8180篇 |
2010年 | 5795篇 |
2009年 | 5754篇 |
2008年 | 7295篇 |
2007年 | 7212篇 |
2006年 | 6851篇 |
2005年 | 6219篇 |
2004年 | 5704篇 |
2003年 | 5272篇 |
2002年 | 5029篇 |
2001年 | 6218篇 |
2000年 | 4702篇 |
1999年 | 3567篇 |
1998年 | 2785篇 |
1997年 | 2745篇 |
1996年 | 2656篇 |
1995年 | 2490篇 |
1994年 | 2383篇 |
1993年 | 2218篇 |
1992年 | 2869篇 |
1991年 | 2773篇 |
1990年 | 2716篇 |
1989年 | 2736篇 |
1988年 | 2751篇 |
1987年 | 2758篇 |
1986年 | 2628篇 |
1985年 | 3366篇 |
1984年 | 3379篇 |
1983年 | 2655篇 |
1982年 | 2774篇 |
1981年 | 2823篇 |
1980年 | 2603篇 |
1979年 | 2939篇 |
1978年 | 2913篇 |
1977年 | 3028篇 |
1976年 | 2858篇 |
1975年 | 2596篇 |
1974年 | 2562篇 |
1973年 | 2502篇 |
1972年 | 1735篇 |
1968年 | 1719篇 |
排序方式: 共有10000条查询结果,搜索用时 136 毫秒
191.
P. Dimopoulos K. Farakos S. Nicolis 《The European Physical Journal C - Particles and Fields》2002,24(2):287-296
We explore the phase diagram of the five-dimensional anisotropic Abelian Higgs model by Monte Carlo simulations. In particular,
we study the transition between the confining phase and the four-dimensional layered Higgs phase. We find that, in a certain
region of the lattice parameter space, this transition can be first order, and that each layer moves into the Higgs phase
independently of the others (decoupling of layers). As the Higgs couplings vary, we find, using mean field techniques, that
this transition may probably become second order.
Received: 21 December 2001 / Published online: 12 April 2002 相似文献
192.
A cooperative defect-deformation (DD) mechanism is developed for the nucleation of the quasi-monodisperse ensemble of nanoparticles in the low-temperature deposition of Ga atoms in the presence of laser radiation. A comparison with experiment is carried out, and a good agreement between the theoretical and experimental results has been obtained. In particular, in accordance with the DD model, it has been found that the arrangement of nanoparticles is characterized by a latent hexagonal order, and their shape is quasi-hexagonal. It has been shown that the characteristics of the deposited ensemble of nanoparticles can be controlled with the use of an anisotropic deformation. 相似文献
193.
194.
Translated from Programmnoe Oborudovanie i Voprosy Prinyatiya Reshenii, pp. 152–184, 1989. 相似文献
195.
V. K. Mel'nikov 《Communications in Mathematical Physics》1991,137(2):359-381
It is shown that the nonlinear Schroedinger equation with a self-consistent source admits investigation by the inverse scattering method for the Dirac operator. The conditions are found under which the solutions of the nonlinear Schroedinger equation with a self-consistent source describe the creation and annihilation of solitons. 相似文献
196.
197.
J. Pill J. Aufenanger K. Stegmeier F. H. Schmidt D. Müller 《Fresenius' Journal of Analytical Chemistry》1987,327(5-6):558-560
Summary The investigation methods of the action of xenobiotics on sterol biosynthesis from 14C-acetate in rat hepatocyte cultures can be developed, with regard to extraction using Extrelut and the separation of the sterol pattern by thin-layer chromatography, in such a way that they are suitable for wider application, e.g., screening. Good visualisation and recognition of changes in the sterol pattern are possible using autoradiography of the thin-layer chromatogram.
Dedicated to Dr. E. Roesch on occasion of his 65th birthday 相似文献
Dünnschicht-Chromatographie von radioaktiv markiertem Cholesterin und Vorstufen aus biologischem Material. Eine einfache und empfindliche Methode zur Untersuchung einer Beeinflussung des Sterolbiosynthesewegs
Dedicated to Dr. E. Roesch on occasion of his 65th birthday 相似文献
198.
199.
A. V. Boldashevskii Zh. K. Tukhmetova Sh. B. Kasenova S. M. Adekenov A. Nukhuly B. K. Kasenov A. M. Gazaliev S. D. Fazylov 《Russian Journal of Applied Chemistry》2006,79(10):1705-1708
Results of thermochemical studies of a new compound, potassium morpholinodithiocarbamate, are presented. The enthalpies of its solution in water at various dilutions and the specific heat at 173–348 K were examined by the experimental methods of isothermal and dynamic calorimetry. 相似文献
200.
Using a photoelastic modulator-based novel set-up, the electric field-induced in-plane birefringence and the optical rotatory power (ORP) were measured of an antiferroelectric liquid crystalline compound (12OF1M7) in its various phases using 30 µm homeotropic cells. Some specific signatures of the in-plane birefringence and of the ORP for the various phases are being established. A relatively small threshold field is needed for the unwinding process of the antiferroelectric phase with a unit cell of four layers [SmCA*(1/2)] compared with that for two layers [SmCA*(0)]. On application of the electric field on the high temperature side of the SmCA*(1/2) phase (80.1-81.5°C), a field-induced phase transition is shown to occur directly to the SmC* phase, whereas on the lower temperature side (79.4-80.1°C) the transition takes place to SmC* via the SmCA*(1/3) phase. The in-plane birefringence exhibits a critical power law dependence for the SmC*-SmA transition. The ORP changes sign within the temperature range of the phase with a unit cell of three layers, reflecting a change in the handedness during this phase. Using tilted conoscopy, the results for the biaxiality and the apparent tilt angle for a smectic liquid crystal with a tilt angle greater than 18° in the ferroelectric phase are reported. The biaxiality implies the difference in the refractive indices between the two minor axes of the refractive index ellipsoid. The optical transmittance at visible and IR wavelengths for free-standing films reveal characteristic reflection bands for these phases. The modulated structures of the reflected bands appear just above the SmCA* phase and below SmCA*(1/3); these are possibly due to an easy deformation of the phase by the surfaces. 相似文献