全文获取类型
收费全文 | 116058篇 |
免费 | 24607篇 |
国内免费 | 17247篇 |
专业分类
化学 | 74885篇 |
晶体学 | 1254篇 |
力学 | 6116篇 |
综合类 | 22篇 |
数学 | 16121篇 |
物理学 | 59514篇 |
出版年
2023年 | 943篇 |
2022年 | 1038篇 |
2021年 | 1268篇 |
2020年 | 1640篇 |
2019年 | 2196篇 |
2018年 | 2128篇 |
2017年 | 2739篇 |
2016年 | 3363篇 |
2015年 | 3423篇 |
2014年 | 3565篇 |
2013年 | 6617篇 |
2012年 | 6734篇 |
2011年 | 8592篇 |
2010年 | 10778篇 |
2009年 | 10716篇 |
2008年 | 5423篇 |
2007年 | 4949篇 |
2006年 | 4557篇 |
2005年 | 4714篇 |
2004年 | 5416篇 |
2003年 | 4395篇 |
2002年 | 4100篇 |
2001年 | 3650篇 |
2000年 | 2782篇 |
1999年 | 3000篇 |
1998年 | 2568篇 |
1997年 | 2419篇 |
1996年 | 2650篇 |
1995年 | 3080篇 |
1994年 | 3190篇 |
1993年 | 3240篇 |
1992年 | 2802篇 |
1991年 | 2439篇 |
1990年 | 2064篇 |
1989年 | 2183篇 |
1988年 | 2128篇 |
1987年 | 1383篇 |
1986年 | 1451篇 |
1985年 | 1271篇 |
1984年 | 1400篇 |
1983年 | 722篇 |
1982年 | 1283篇 |
1981年 | 1082篇 |
1980年 | 1151篇 |
1979年 | 866篇 |
1978年 | 885篇 |
1977年 | 966篇 |
1976年 | 1308篇 |
1973年 | 632篇 |
1972年 | 655篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
61.
62.
ON A PAIR OF NON-ISOMETRIC ISOSPECTRAL DOMAINS WITH FRACTAL BOUNDARIES AND THE WEYL-BERRY CONJECTURE
ONAPAIROFNONISOMETRICISOSPECTRALDOMAINSWITHFRACTALBOUNDARIESANDTHEWEYLBERRYCONJECTURESLEEMAN,B.D.CHENHUAManuscriptrec... 相似文献
63.
64.
65.
Open circuit voltage (OCV) measurements in H2O/air concentration cells at T<580 K using Yb-doped SrCeO3 electrolyte indicate that under these conditions, protons are transported through the electrolyte as -ve ions, possibly as
hydroxyl (OH−) ions. The H+ ionic transport, which is generally reported, becomes the dominant mode for H2O/air concentration cells at temperatures greater than 750 K or when H2O/air electrodes are replaced by H2/Ar, and the anomalous OCV sign disappears. The combination of low temperature and the presence of hydrogen and oxygen as
provided by the H2O/air system appears to be necessary for the postulated hydroxyl ion electrode reactions to take place.
In addition to OCV measurements, results from impedance spectroscopy are used to provide evidence in support of the suggested
hydroxyl ion mode of protonic transport under the specified conditions. These findings are directly relevant in the development
of novel humidity sensors in the temperature range 450–580K and is reported in a separate paper in this conference.
Paper presented at the 3rd Euroconference on Solid State Ionics, Teulada, Sardinia, Italy, Sept. 15–22, 1996 相似文献
66.
Peter Imkeller 《Probability Theory and Related Fields》1996,106(1):105-135
Summary. The analytic treatment of problems related to the asymptotic behaviour of random dynamical systems generated by stochastic
differential equations suffers from the presence of non-adapted random invariant measures. Semimartingale theory becomes accessible
if the underlying Wiener filtration is enlarged by the information carried by the orthogonal projectors on the Oseledets spaces
of the (linearized) system.
We study the corresponding problem of preservation of the semimartingale property and the validity of a priori inequalities
between the norms of stochastic integrals in the enlarged filtration and norms of their quadratic variations in case the random
element F enlarging the filtration is real valued and possesses an absolutely continuous law. Applying the tools of Malliavin’s calculus,
we give smoothness conditions on F under which the semimartingale property is preserved and a priori martingale inequalities are valid.
Received: 12 April 1995 / In revised form: 7 March 1996 相似文献
67.
A. Negr n-Mendoza G. Albarran S. Ramos-Bernal 《Radiation Physics and Chemistry》1993,42(4-6):1003-1006
The effect of clay on the radiolysis of malonic acid solutions was studied. The results showed an enhanced of decarboxylation rather than condensation reactions. 相似文献
68.
Peter J. Grabner 《Random Structures and Algorithms》1993,4(1):99-110
We investigate the following process: N people select b losers by flipping coins. The 0-party continues until there are less than b losers; then the 1-party has to find the other losers by the same process. The average time for this process is about long2 N, but this result requires rather advanced methods. Furthermore, the average size of a binary tree associated to this process and the average number of coin flippings are computed. The method used in this article can be used to give asympotical solutions of a special type of bivariate recurrences. © 1993 John Wiley & Sons, Inc. 相似文献
69.
Peter A. McCoy 《Journal of Mathematical Analysis and Applications》2002,275(2):761-770
An integral transform based method is given for determining information about the locating and properties of singularities of electromagnetic fields associated with axially symmetric radiating sources. 相似文献
70.
An M/G/1 retrial queueing system with additional phase of service and possible preemptive resume service discipline is considered. For an arbitrarily distributed retrial time distribution, the necessary and sufficient condition for the system stability is obtained, assuming that only the customer at the head of the orbit has priority access to the server. The steady-state distributions of the server state and the number of customers in the orbit are obtained along with other performance measures. The effects of various parameters on the system performance are analysed numerically. A general decomposition law for this retrial queueing system is established. 相似文献