全文获取类型
收费全文 | 90204篇 |
免费 | 7515篇 |
国内免费 | 10634篇 |
专业分类
化学 | 54154篇 |
晶体学 | 2291篇 |
力学 | 6108篇 |
综合类 | 813篇 |
数学 | 14682篇 |
物理学 | 30305篇 |
出版年
2024年 | 165篇 |
2023年 | 816篇 |
2022年 | 1897篇 |
2021年 | 1951篇 |
2020年 | 2336篇 |
2019年 | 2257篇 |
2018年 | 1960篇 |
2017年 | 2256篇 |
2016年 | 2825篇 |
2015年 | 2514篇 |
2014年 | 3479篇 |
2013年 | 6244篇 |
2012年 | 5272篇 |
2011年 | 4481篇 |
2010年 | 3768篇 |
2009年 | 5345篇 |
2008年 | 5775篇 |
2007年 | 6209篇 |
2006年 | 5415篇 |
2005年 | 4585篇 |
2004年 | 4207篇 |
2003年 | 4111篇 |
2002年 | 4459篇 |
2001年 | 3243篇 |
2000年 | 3202篇 |
1999年 | 2654篇 |
1998年 | 2481篇 |
1997年 | 1660篇 |
1996年 | 1614篇 |
1995年 | 1433篇 |
1994年 | 1444篇 |
1993年 | 1076篇 |
1992年 | 1183篇 |
1991年 | 760篇 |
1990年 | 678篇 |
1989年 | 526篇 |
1988年 | 488篇 |
1987年 | 438篇 |
1986年 | 385篇 |
1985年 | 392篇 |
1984年 | 362篇 |
1983年 | 236篇 |
1982年 | 288篇 |
1981年 | 260篇 |
1980年 | 198篇 |
1979年 | 230篇 |
1978年 | 173篇 |
1977年 | 157篇 |
1976年 | 112篇 |
1973年 | 103篇 |
排序方式: 共有10000条查询结果,搜索用时 481 毫秒
131.
132.
We consider Markov processes built from pasting together pieces of strong Markov processes which are killed at a position
dependent rate and connected via a transition kernel. We give necessary and sufficient conditions for local absolute continuity
of probability laws for such processes on a suitable path space and derive an explicit formula for the corresponding likelihood
ratio process. The main tool is the consideration of the process between successive jumps – what we call ‘elementary experiments’
– and criteria for absolute continuity of laws of the process there. We apply our results to systems of branching diffusions
with interactions and immigrations.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
133.
Patrick Dehornoy 《Algebra Universalis》2002,48(2):223-248
We solve the word problem of the identity x(yz) = (xy)(yz) by investigating a certain group describing the geometry of that identity. We also construct a concrete realization of the
one-generated free algebra relative to the above identity.
Received March 23, 2001; accepted in final form July 6, 2002. 相似文献
134.
135.
The rotational spectra of the deuterium cyanide isotopic species DCN, D13CN, DC15N, and D13C15N were recorded in the vibrational ground and first excited bending state (v2=1) up to 2 THz. The R-branch transitions from J=3←2 to J=13←12 were measured with sub-Doppler resolution. These very high resolution (∼70 kHz) and precise (±3-10 kHz) saturation dip measurements allowed for resolving the underlying hyperfine structure due to the 14N nucleus in DCN and D13CN for transitions as high as J=10←9. Additional high JR-branch (J=25←24 to J=28←27) transitions around 2 THz and direct l-type (ΔJ=0, J=19 to J=25) transitions from 66 to 118 GHz were recorded in Doppler-limited resolution. For the ground state of D13C15N, the J=1←0 transition was measured for the first time. The transition frequency accuracies for the other deuterated species were significantly improved. These new experimental data, together with the available infrared rovibrational data and previously measured direct l-type transitions, were subjected to a global least squares analysis for each isotopomer. This yielded precise sets of molecular constants for the ground and first excited vibrational states, including the nuclear quadrupole and magnetic spin-rotation coupling constants of the 14N nucleus for DCN and D13CN. The hyperfine structure due to the D, 13C, and 15N nuclei have not been resolved, but led to a broadening of the observed saturation dips. 相似文献
136.
Let {Xk}k?1 be a strictly stationary time series. For a strictly increasing sampling function g:?→? define Yk=Xg(k) as the deterministic sub‐sampled time series. In this paper, the extreme value theory of {Yk} is studied when Xk has representation as a moving average driven by heavy‐tailed innovations. Under mild conditions, convergence results for a sequence of point processes based on {Yk} are proved and extremal properties of the deterministic sub‐sampled time series are derived. In particular, we obtain the limiting distribution of the maximum and the corresponding extremal index. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
137.
A convective flow CO laser composed of polytetrafluoroethylene discharge tubes, nickel–chromium steel components, a cupric heat exchanger and other components is described. Operating in liquid nitrogen condition, output power of 60 W has been obtained from a non-selective cavity. 相似文献
138.
A. Khrennikov 《Annalen der Physik》2003,12(10):575-585
We study the probabilistic consequences of the choice of the basic number field in the quantum formalism. We demonstrate that by choosing a number field for a linear space representation of quantum model it is possible to describe various interference phenomena. We analyse interference of probabilistic alternatives induced by real, complex, hyperbolic (Clifford) and p‐adic representations. 相似文献
139.
140.
平行机半在线排序问题研究(Ⅰ) 总被引:15,自引:1,他引:14
对半在线平行机排序问题的研究进展作了详细综述和进一步探讨。文章给出半在线排序问题的背景、定义、分类和求解。介绍它们定义和在不同机器环境和目标函数下半在线排序问题分类,以及第一类半在线模型的近似算法的设计及其竞争比分析。 相似文献