全文获取类型
收费全文 | 11403篇 |
免费 | 339篇 |
国内免费 | 7篇 |
专业分类
化学 | 5673篇 |
晶体学 | 67篇 |
力学 | 299篇 |
综合类 | 3篇 |
数学 | 2434篇 |
物理学 | 3273篇 |
出版年
2021年 | 104篇 |
2020年 | 172篇 |
2019年 | 146篇 |
2018年 | 218篇 |
2017年 | 182篇 |
2016年 | 401篇 |
2015年 | 373篇 |
2014年 | 392篇 |
2013年 | 729篇 |
2012年 | 558篇 |
2011年 | 634篇 |
2010年 | 385篇 |
2009年 | 346篇 |
2008年 | 421篇 |
2007年 | 380篇 |
2006年 | 314篇 |
2005年 | 220篇 |
2004年 | 217篇 |
2003年 | 211篇 |
2002年 | 200篇 |
2001年 | 209篇 |
2000年 | 202篇 |
1999年 | 160篇 |
1998年 | 150篇 |
1997年 | 139篇 |
1996年 | 125篇 |
1995年 | 107篇 |
1994年 | 114篇 |
1993年 | 117篇 |
1992年 | 121篇 |
1991年 | 97篇 |
1990年 | 106篇 |
1989年 | 95篇 |
1988年 | 91篇 |
1987年 | 99篇 |
1986年 | 93篇 |
1985年 | 133篇 |
1984年 | 142篇 |
1983年 | 112篇 |
1982年 | 118篇 |
1981年 | 125篇 |
1980年 | 107篇 |
1979年 | 121篇 |
1978年 | 115篇 |
1977年 | 103篇 |
1976年 | 121篇 |
1975年 | 113篇 |
1974年 | 123篇 |
1973年 | 100篇 |
1968年 | 86篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
Miloslav Duchoň Anatolij Dvurečenskij Paolo de Lucia 《International Journal of Theoretical Physics》1997,36(9):1941-1958
We present a solution to the moment problem for effect algebras, concerning mean values of all powers of an observable concentrated
on the interval [0, 1] for states from a convex set. We give a solution for particular examples, e.g., for the set of all
effect operators. We examine how this problem is related to a socalled E-property. Finally, we give a solution for observables
studied in the operational approach to physical theories. 相似文献
33.
Dislocation motion in the real lattice of alloys is highly complex. In a certain temperature range the dynamic strain ageing phenomena have been reported. In this paper the influence of mobile solute atoms (as obstacles) on the motion of dislocation is analysed. Both processes are assumed to be thermally activated. A new model based on this assumption is proposed. The dislocation velocity and the friction stress (due to solute-dislocation interactions) are calculated. A change in the friction stress caused by solute mobility is discussed. 相似文献
34.
Michael Grätzel 《Journal of Sol-Gel Science and Technology》1994,2(1-3):673-677
Transparent nanocrystalline films of oxide semiconductors such as TiO2 and Fe2O3 have been prepared on a conducting glass support employing a sol-gel procedure. The films are composed of nanometer-sized particles sintered together to allow for percolative charge carrier transport. The internal surface of these films is very high, roughness factors of the order of 1000 being readily obtained. Electric polarization was applied for forward and reverse biasing of the films and the resulting optical changes have been analyzed to derive their flat band potential. Band gap excitation of such nanocrystalline semiconductors produces electron-hole pairs which migrate through the film to be collected as electric current. Steady state photolysis and time resolved laser techniques have been applied to scrutinize the mechanism of light induced charge separation within the nanostructure. When derivatized with a suitable chromophore, TiO2 films give extraordinary efficiencies for the conversion of incident photons into electric current, exceeding 90% for certain transition metal complexes within the wavelength range of their absorption band. The underlying physical principles of these astonishing findings will be discussed. Exploiting this discovery, we have developed a new type of photovoltaic device whose overall light to electric energy conversion yield is 10% under simulated AM 1.5 solar radiation. 相似文献
35.
36.
37.
Š. Jakševičius 《Lithuanian Mathematical Journal》1992,32(2):174-180
Kaunas Academy of Agriculture, 4324 Noreikiškés, Lithuania. Translated from Lietuvos Matematikos Rinkinys, Vol. 32, No. 2,
pp. 221–228, April–June, 1992. 相似文献
38.
39.
Experimental Techniques - 相似文献
40.
The paper is devoted to the research of large deviation probabilities in the approximation by compound Poisson law. 相似文献