全文获取类型
收费全文 | 289351篇 |
免费 | 3103篇 |
国内免费 | 818篇 |
专业分类
电工技术 | 5057篇 |
综合类 | 162篇 |
化学工业 | 45604篇 |
金属工艺 | 11926篇 |
机械仪表 | 8625篇 |
建筑科学 | 6908篇 |
矿业工程 | 1843篇 |
能源动力 | 6791篇 |
轻工业 | 26055篇 |
水利工程 | 3201篇 |
石油天然气 | 7098篇 |
武器工业 | 16篇 |
无线电 | 31617篇 |
一般工业技术 | 57139篇 |
冶金工业 | 51995篇 |
原子能技术 | 7561篇 |
自动化技术 | 21674篇 |
出版年
2021年 | 2107篇 |
2018年 | 3693篇 |
2017年 | 3638篇 |
2016年 | 3912篇 |
2015年 | 2483篇 |
2014年 | 4254篇 |
2013年 | 12082篇 |
2012年 | 6871篇 |
2011年 | 9273篇 |
2010年 | 7614篇 |
2009年 | 8694篇 |
2008年 | 8981篇 |
2007年 | 8865篇 |
2006年 | 7876篇 |
2005年 | 7350篇 |
2004年 | 6826篇 |
2003年 | 6590篇 |
2002年 | 6659篇 |
2001年 | 6528篇 |
2000年 | 6214篇 |
1999年 | 6258篇 |
1998年 | 14922篇 |
1997年 | 11157篇 |
1996年 | 8651篇 |
1995年 | 6578篇 |
1994年 | 5967篇 |
1993年 | 5824篇 |
1992年 | 4504篇 |
1991年 | 4456篇 |
1990年 | 4309篇 |
1989年 | 4324篇 |
1988年 | 4277篇 |
1987年 | 3611篇 |
1986年 | 3608篇 |
1985年 | 4180篇 |
1984年 | 3976篇 |
1983年 | 3640篇 |
1982年 | 3437篇 |
1981年 | 3581篇 |
1980年 | 3438篇 |
1979年 | 3388篇 |
1978年 | 3466篇 |
1977年 | 3954篇 |
1976年 | 5088篇 |
1975年 | 3183篇 |
1974年 | 3017篇 |
1973年 | 3039篇 |
1972年 | 2658篇 |
1971年 | 2484篇 |
1970年 | 2113篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
271.
P. S. Gordienko V. A. Kolzunov L. G. Zorina T. A. Kaidalova S. B. Yarusova 《Theoretical Foundations of Chemical Engineering》2008,42(5):680-683
The possibility of processing fluorine-containing wastes of fluorite ore, which include fluorite, calcite, quartz, and anorthite, has been investigated. A manufacturing flow chart of the complex processing of the ore waste materials with the production of sodium fluoride, alumina, soda ash, and raw materials suitable for the production of Portland cement and wollastonite is suggested. 相似文献
272.
Some sulfides of gold and silver: Composition,mineral mineral assemblage,and conditions of formation
Characteristic mineral assemblage and special features of the composition of Au and Ag sulfides of gold-silver deposits have been established. The forms of the occurrence of Au and Ag in the minerals of the early and last stages have been analyzed. The conditions for the formation of uytenbogaardtite and petrovskaite in supergene and low-temperature hydrothermal processes have been considered. A thermodynamic model explaining their genesis in the oxidation zones is presented. 相似文献
273.
V. M. Vorotyntsev G. M. Mochalov M. A. Kolotilova S. S. Suvorov A. V. Koroleva A. Yu. Sharov 《Theoretical Foundations of Chemical Engineering》2008,42(2):197-202
The results of theoretical and experimental studies for the kinetics of separating dichlorosilane from a mixture of volatile chlorosilanes and ultrapurifying the dichlorosilane concentrate by batch distillation are reported. A mathematical model of the process is proposed. It is shown that the model and computational algorithm adequately describe both processes. The obtained experimental and theoretical data made it possible to design a concentration and ultrapurification process with a maximal productivity at a specified product purity. 相似文献
274.
Digant Gupta Christopher G Lis Sadie L Dahlk Jessica King Pankaj G Vashi James F Grutsch Carolyn A Lammersfeld 《Nutrition journal》2008,7(1):19
Background
Bioelectrical Impedance (BIA) derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA) is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer. 相似文献275.
Cloning of observables, unlike standard cloning of states, aims at copying the information encoded in the statistics of a
class of observables rather then on quantum states themselves. In such a process the emphasis is on the quantum operation
(evolution plus measurement) necessary to retrieve the original information. We analyze, for qubit systems, the cloning of
a class generated by two noncommuting observables, elucidating the relationship between such a process and joint measurements.
This helps in establishing an optimality criterion for cloning of observables. We see that, even if the cloning machine is
designed to act on the whole class generated by two noncommuting observables, the same optimal performances of a joint measurement
can be attained. Finally, the connection with state dependent cloning is enlightened. 相似文献
276.
277.
E. P. Velikhov N. N. Ponomarev-Stepnoi V. G. Volkov G. G. Gorodetskii Yu. A. Zverkov O. P. Ivanov S. M. Koltyshev V. D. Muzrukova S. G. Semenov V. E. Stepanov A. V. Chesnokov A. D. Shisha 《Atomic Energy》2007,102(5):375-381
This article is devoted to work done in 2002–2006 as part of the unified project Reabilitatsiya to rehabilitate radiation
hazardous objects and sections of the radioactively contaminated territory of the Russian Science Center Kurchatov Institute.
The main objects of the rehabilitation work were old storage sites built for radioactive wastes on the territory of the Institute
when military and civilian nuclear technologies were under development. The structural features of the storage sites, including
the volumes and characteristics of the wastes stored, are presented. The salient aspects of the disposal sites, taken into
account during the rehabilitation work, are discussed. The organization of the rehabilitation operations and the sequence
in which they are performed, the special features of the technical design solutions used, the technological methods, and ways
for conducting the work are described.
__________
Translated from Atomnaya énergiya, Vol. 102, No. 5, pp. 300–306, May, 2007. 相似文献
278.
279.
Rolf G. Kuehni 《Color research and application》2008,33(1):5-9
Some 100 years before Albert Munsell developed his color order system, French silk merchant and inventor of a technology for producing works of art in silk velours, Gaspard Grégoire, introduced a color order system based on the color attributes hue, (relative) chroma, and lightness. Conceived in the mid‐1780s, an atlas with 1350 samples was produced before 1813 and found use in French Royal manufacturing operations and educational institutions. It was followed a few years later by one with 343 samples. Grégoire's work was subsequently overshadowed by Michel‐Eugene Chevreul's more complicated and less intuitive hemispherical system of 1839. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 5–9, 2008 相似文献
280.