全文获取类型
收费全文 | 265656篇 |
免费 | 792篇 |
国内免费 | 285篇 |
专业分类
化学 | 116714篇 |
晶体学 | 3765篇 |
力学 | 15986篇 |
综合类 | 7篇 |
数学 | 43908篇 |
物理学 | 86353篇 |
出版年
2019年 | 2299篇 |
2018年 | 10875篇 |
2017年 | 11632篇 |
2016年 | 7729篇 |
2015年 | 2550篇 |
2014年 | 3697篇 |
2013年 | 7154篇 |
2012年 | 9367篇 |
2011年 | 17671篇 |
2010年 | 11671篇 |
2009年 | 12025篇 |
2008年 | 15708篇 |
2007年 | 18946篇 |
2006年 | 5807篇 |
2005年 | 10451篇 |
2004年 | 7576篇 |
2003年 | 7460篇 |
2002年 | 5857篇 |
2001年 | 5148篇 |
2000年 | 4014篇 |
1999年 | 2868篇 |
1998年 | 2648篇 |
1997年 | 2476篇 |
1996年 | 2445篇 |
1995年 | 2159篇 |
1994年 | 2106篇 |
1993年 | 2129篇 |
1992年 | 2151篇 |
1991年 | 2465篇 |
1990年 | 2389篇 |
1989年 | 2476篇 |
1988年 | 2371篇 |
1987年 | 2394篇 |
1986年 | 2210篇 |
1985年 | 2754篇 |
1984年 | 2790篇 |
1983年 | 2419篇 |
1982年 | 2464篇 |
1981年 | 2369篇 |
1980年 | 2171篇 |
1979年 | 2507篇 |
1978年 | 2670篇 |
1977年 | 2676篇 |
1976年 | 2803篇 |
1975年 | 2593篇 |
1974年 | 2520篇 |
1973年 | 2729篇 |
1972年 | 2194篇 |
1971年 | 2000篇 |
1970年 | 1881篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
151.
Vinod Kumar Pragya Das R.P. Singh S. Muralithar R.K. Bhowmik 《The European Physical Journal A - Hadrons and Nuclei》2003,17(2):153-157
The fusion evaporation reaction 122Sn(14N, 4n)132La was used to populate the high-spin states of 132La at the beam energy of 60 MeV. A new band consisting of mostly E2 transitions has been discovered. This band has the interesting links to the ground state 2- and the isomeric state 6-. A new transition of energy 351 keV connecting the low-spin states of the positive-parity band based on the πh
11/2 ⊗ νh
11/2 particle configuration, has been found. This has played a very important role in resolving the existing ambiguities and inconsistencies
in the spin assignment of the band head.
Received: 12 August 2002 / Accepted: 18 March 2003 / Published online: 7 May 2003 相似文献
152.
M. D. Srinivas 《Pramana》2003,60(6):1137-1152
We derive an optimal bound on the sum of entropic uncertainties of two or more observables when they are sequentially measured
on the same ensemble of systems. This optimal bound is shown to be greater than or equal to the bounds derived in the literature
on the sum of entropie uncertainties of two observables which are measured on distinct but identically prepared ensembles
of systems. In the case of a two-dimensional Hilbert space, the optimum bound for successive measurements of two-spin components,
is seen to be strictly greater than the optimal bound for the case when they are measured on distinct ensembles, except when
the spin components are mutually parallel or perpendicular 相似文献
153.
For the decay of two identical particles with close momenta, the angular correlations between the directions of emission of decay products are considered on the basis of the model of independent single-particle sources emitting unstable unpolarized particles of nonzero spin. These correlations reflect spin correlations that are caused by quantum-statistics and final-state-interaction effects. A general theory of angular correlations in the decays of two arbitrarily polarized particles (resonances) is constructed. 相似文献
154.
155.
Howard Anton and Robert C. Busby, John Wiley & Sons, Inc., 2002. 相似文献
156.
Guangchang Zhou Jibao He Issifu I. Harruna 《Journal of polymer science. Part A, Polymer chemistry》2007,45(18):4204-4210
Amphiphilic tris(2,2′‐bipyridine)ruthenium‐cored star‐shaped polymers consisting of one polystyrene block and two poly(N‐isopropylacrylamide) blocks were prepared by the “arm‐first” method in which RAFT polymerization and nonconvalent ligand–metal complexation were employed. The prepared amphiphilic star‐shaped metallopolymers are able to form micelles in water. The size and distribution of the micelles were studied by dynamic light scattering and transmission electron microscopy techniques. Preliminary studies indicate that the polymer concentration and the hydrophilic poly(N‐isopropylacrylamide) block length can affect the morphologies of the formed metal‐interfaced core–shell micelles in water. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4204–4210, 2007 相似文献
157.
V. P. Ershov D. A. Kas’yanov V. I. Rodchenkov D. A. Sergeev 《Crystallography Reports》2008,53(2):339-343
The growth of the isolated (100) face of a KDP crystal at exposure of the phase boundary to the initial ultrasound field and a standing acoustic wave has been investigated. A significant growth response of this face, exposed to sound normally along the acoustic axis in the near zone of a piston-like half-wave vibrator with f = 20 kHz and tangentially in the pulsed two-frequency (f = 600 and 900 kHz) standing-wave mode, has been revealed. It is shown that the mechanisms of mass exchange enhancement in these acoustic modes are different. The results obtained show a fundamental possibility of controlling crystal growth and dissolution by varying the parameters of inhomogeneous acoustic field. 相似文献
158.
A. P. Voronov G. N. Babenko V. M. Puzikov A. D. Roshal’ V. I. Salo 《Crystallography Reports》2008,53(4):708-712
The features of doping of KDP crystals with cerium ions and organocerium complexes with alizarin complexon and arsenazo III have been investigated. It is established that “direct” doping by introducing cerium salts into the initial solution cannot be implemented. The effect of organometallic complexes of cerium on the crystal growth has been studied. Organocerium complexes predominantly enter the prismatic or pyramidal growth sectors. It is shown that the complex arsenazo III + Ce blocks the growth of the prismatic sector. Cerium-doped KDP crystals exhibit a photoluminescence band peaking at the wavelength λmax= 350 nm. 相似文献
159.
O. M. Ostrikov 《Mechanics of Solids》2008,43(5):793-797
We propose a dislocation model of a nanotwin, which is used to calculate the stress fields in the nanotwin. We consider the role of these stresses in the process of interdislocation interaction and nanotwin growth. 相似文献
160.
I. D. Lomako M. I. Danil’kevich D. V. Karpinskiĭ I. I. Makoed 《Crystallography Reports》2008,53(2):278-284
The experimental and calculated values of the optical permittivity ε∞ have been analyzed and generalized with allowance for the oxygen concentration and possible valences of Fe and O ions in YIG single crystals. It is shown that the deficit of oxygen ions in the samples is accompanied by a decrease in ε∞. A decrease in the gradient of distribution of Ba ions over the sample thickness decreases the difference between the calculated and experimental values. It is revealed that the ratio of the number of valence electrons to the number of core electrons, with regard to their polarizabilities, is proportional to the ratio of the incoherent and coherent X-ray scattering intensities, nk/k. 相似文献