全文获取类型
收费全文 | 18457篇 |
免费 | 552篇 |
国内免费 | 370篇 |
专业分类
化学 | 2336篇 |
晶体学 | 77篇 |
力学 | 308篇 |
综合类 | 50篇 |
数学 | 15029篇 |
物理学 | 1579篇 |
出版年
2023年 | 50篇 |
2022年 | 139篇 |
2021年 | 130篇 |
2020年 | 133篇 |
2019年 | 481篇 |
2018年 | 544篇 |
2017年 | 266篇 |
2016年 | 238篇 |
2015年 | 282篇 |
2014年 | 568篇 |
2013年 | 1108篇 |
2012年 | 683篇 |
2011年 | 1253篇 |
2010年 | 940篇 |
2009年 | 1238篇 |
2008年 | 1314篇 |
2007年 | 1439篇 |
2006年 | 1078篇 |
2005年 | 775篇 |
2004年 | 617篇 |
2003年 | 548篇 |
2002年 | 400篇 |
2001年 | 369篇 |
2000年 | 372篇 |
1999年 | 433篇 |
1998年 | 371篇 |
1997年 | 305篇 |
1996年 | 344篇 |
1995年 | 343篇 |
1994年 | 355篇 |
1993年 | 305篇 |
1992年 | 263篇 |
1991年 | 162篇 |
1990年 | 180篇 |
1989年 | 166篇 |
1988年 | 118篇 |
1987年 | 117篇 |
1986年 | 90篇 |
1985年 | 140篇 |
1984年 | 112篇 |
1983年 | 66篇 |
1982年 | 111篇 |
1981年 | 84篇 |
1980年 | 78篇 |
1979年 | 44篇 |
1978年 | 65篇 |
1977年 | 59篇 |
1976年 | 46篇 |
1975年 | 19篇 |
1974年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
The ρ-T curves in our single phase HgBa2Ca2Cu3O8+δ superconductor were measured as a function of temperature and magnetic field, ρ=ρ0exp(−Ueff/κBT). It can be transformed to another form d(lnρ)/d(1/T)=−Ueff+TdUeff/dT, then this becomes a plot of the activation energy Ueff as a function of temperature. Our data plotted in these ways show a clear crossover from high-temperature two-dimensional vortex-liquid to a critical region associated with the low-temperature three-dimensional vortex-glass phase transition. The critical exponents v(z−1)=3.9±1.9 in this system are little different with previous measurements in BSCCO and YBCO systems. 相似文献
52.
Murad Özaydin 《Journal of Functional Analysis》2004,215(1):241-252
We classify all functions on a locally compact, abelian group giving equality in an entropy inequality generalizing the Heisenberg Uncertainty Principle. In particular, for functions on a real line, we proof a conjecture of Hirschman published in 1957. 相似文献
53.
54.
S. Pumplün 《manuscripta mathematica》1998,97(1):93-108
For a Brauer–Severi variety X over a field k of characteristic not two, every symmetric bilinear space over X up to Witt equivalence is defined over k.
Received: 2 February 1998 相似文献
55.
We investigate several versions of a cardinal characteristic defined by Frankiewicz. Vojtáš showed , and Blass showed . We show that all the versions coincide and that is greater than or equal to the splitting number. We prove the consistency of and of .
Received: 2 October 1996 / Revised version: 22 May 1997 相似文献
56.
Dorina Mitrea Marius Mitrea Jill Pipher 《Journal of Fourier Analysis and Applications》1997,3(2):131-192
We study boundary value problems for the time-harmonic form of the Maxwell equations, as well as for other related systems
of equations, on arbitrary Lipschitz domains in the three-dimensional Euclidean space. The main goal is to develop the corresponding
theory for Lp-integrable bounday data for optimal values of p's. We also discuss a number of relevant applications in electromagnetic scattering. 相似文献
57.
Guido Cortesani 《Annali dell'Universita di Ferrara》1997,43(1):27-49
Let Ω be an open and bounded subset ofR
n
with locally Lipschitz boundary. We prove that the functionsv∈SBV(Ω,R
m
) whose jump setS
vis essentially closed and polyhedral and which are of classW
k, ∞ (S
v,R
m) for every integerk are strongly dense inGSBV
p(Ω,R
m
), in the sense that every functionu inGSBV
p(Ω,R
m
) is approximated inL
p(Ω,R
m
) by a sequence of functions {v
k{j∈N with the described regularity such that the approximate gradients ∇v
jconverge inL
p(Ω,R
nm
) to the approximate gradient ∇u and the (n−1)-dimensional measure of the jump setsS
v
j converges to the (n−1)-dimensional measure ofS
u. The structure ofS
v can be further improved in casep≤2.
Sunto Sia Ω un aperto limitato diR n con frontiera localmente Lipschitziana. In questo lavoro si dimostra che le funzioniv∈SBV(Ω,R m ) con insieme di saltoS v essenzialmente chiuso e poliedrale che sono di classeW k, ∞ (S v,R m ) per ogni interok sono fortemente dense inGSBV p(Ω,R m ), nel senso che ogni funzioneu∈GSBV p(Ω,R m ) è approssimata inL p(Ω,R m ) da una successione di funzioni {v j}j∈N con la regolaritá descritta tali che i gradienti approssimati ∇v jconvergono inL p(Ω,R nm ) al gradiente approssimato ∇u e la misura (n−1)-dimensionale degli insiemi di saltoS v jconverge alla misura (n−1)-dimensionale diS u. La struttura diS vpuó essere migliorata nel caso in cuip≤2.相似文献
58.
59.
Genkai Zhang 《manuscripta mathematica》1998,97(3):371-388
Let X=G
* be a compact Hermitian symmetric space. We study the Berezin transform on L
2(X) and calculate its spectrum under the decomposition of L
2(X) into the irreducible representations of G
*. As applications we find the expansion of powers of the canonical polynomial (Bergman reproducing kernel for the canonical
line bundle) in terms of the spherical polynomials on X, and we find the irreducible decomposition of tensor products of Bergman spaces on X.
Received: 10 September 1996 / Revised version: 10 September 1997 相似文献
60.
Summary. We present a simple proof, based on modified logarithmic Sobolev inequalities, of Talagrand’s concentration inequality for
the exponential distribution. We actually observe that every measure satisfying a Poincaré inequality shares the same concentration
phenomenon. We also discuss exponential integrability under Poincaré inequalities and its consequence to sharp diameter upper
bounds on spectral gaps.
Received: 10 June 1996 / In revised form: 9 August 1996 相似文献