全文获取类型
收费全文 | 379880篇 |
免费 | 2735篇 |
国内免费 | 1026篇 |
专业分类
化学 | 201362篇 |
晶体学 | 5919篇 |
力学 | 17535篇 |
综合类 | 16篇 |
数学 | 43353篇 |
物理学 | 115456篇 |
出版年
2020年 | 3497篇 |
2019年 | 4178篇 |
2018年 | 5838篇 |
2017年 | 5804篇 |
2016年 | 7840篇 |
2015年 | 4229篇 |
2014年 | 7196篇 |
2013年 | 16229篇 |
2012年 | 12367篇 |
2011年 | 14813篇 |
2010年 | 11181篇 |
2009年 | 11215篇 |
2008年 | 14271篇 |
2007年 | 14129篇 |
2006年 | 12870篇 |
2005年 | 11602篇 |
2004年 | 10656篇 |
2003年 | 9735篇 |
2002年 | 9564篇 |
2001年 | 10409篇 |
2000年 | 8060篇 |
1999年 | 6080篇 |
1998年 | 5218篇 |
1997年 | 5330篇 |
1996年 | 4932篇 |
1995年 | 4204篇 |
1994年 | 4401篇 |
1993年 | 4346篇 |
1992年 | 4764篇 |
1991年 | 4891篇 |
1990年 | 4683篇 |
1989年 | 4738篇 |
1988年 | 4600篇 |
1987年 | 4571篇 |
1986年 | 4375篇 |
1985年 | 5644篇 |
1984年 | 5821篇 |
1983年 | 4762篇 |
1982年 | 5023篇 |
1981年 | 4879篇 |
1980年 | 4495篇 |
1979年 | 5039篇 |
1978年 | 5138篇 |
1977年 | 5292篇 |
1976年 | 5311篇 |
1975年 | 4968篇 |
1974年 | 4885篇 |
1973年 | 5108篇 |
1972年 | 3666篇 |
1971年 | 3340篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 891475.
Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 679–680, September–October, 1994. 相似文献
33.
34.
35.
36.
The applicability of differential electrolytic potentiometry as a detection system in flow injection analysis is investigated. A computer-controlled injector which delivers precise volumes of sample solutions in a reproducible manner was developed. Conditions such as current density employed, the concentrations of the solutions used and the flow rate were optimized. Chloride in water was determined by means of this system. The relation between chloride concentration and the measured signal was found to be Nernstian for solutions of concentrations above 6 μg ml−1 chloride. For solutions below this concentration, the relation is linear. 相似文献
37.
V. A. Nebol'sin B. M. Darinskii E. E. Popova A. A. Shchetinin 《Russian Physics Journal》1995,38(10):1023-1026
An estimate of the factors which influence the rate of growth of filamentary silicon crystals in a standard chloride system using a quartz reactor with hot walls is given. It is shown that a diffusion form of crystallization is observed under the conditions investigated.Voronezh State Technical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 22–26, October, 1995. 相似文献
38.
A. E. Dorokhov 《Czechoslovak Journal of Physics》2002,52(3):C79-C90
Nonperturbative nolocal structure of QCD vacuum is well described by instanton model. Specific helicity and flavor structure of zero modes of quarks, in instanton field allows simultaneously to explain some important features of low-and high-energy hadron phenomemology. The basic characteristics of hadron spectrum, partonic sum rules, heavyquark potential etc within the instanton liquid model are briefly discussed. 相似文献
39.
The microhardness and content of carbon in electroplated gold coatings were studied as influenced by the operation time of citrate and citrate-phosphate gold-plating electrolytes. Such physicomechanical properties as porosity, microhardness, internal stress, plasticity, and microstructure of electroless-plated and electroplated nickel coatings were studied and analyzed. 相似文献
40.
A forecasting model is developed for the number of daily applications for loans at a financial services telephone call centre. The purpose of the forecasts and the associated prediction intervals is to provide effective staffing policies within the call centre. The model building process is constrained by the availability of only 2 years and 7 months of data. The distinctive feature of the data is that demand is driven in the main by advertising. The analysis given focuses on applications stimulated by press advertising. Unlike previous analyses of broadly similar data, where ARIMA models were used, a model with a dynamic level, multiplicative calendar effects and a multiplicative advertising response is developed and shown to be effective. 相似文献