全文获取类型
收费全文 | 9606篇 |
免费 | 1086篇 |
国内免费 | 924篇 |
专业分类
电工技术 | 860篇 |
综合类 | 1260篇 |
化学工业 | 434篇 |
金属工艺 | 308篇 |
机械仪表 | 807篇 |
建筑科学 | 1100篇 |
矿业工程 | 336篇 |
能源动力 | 198篇 |
轻工业 | 268篇 |
水利工程 | 338篇 |
石油天然气 | 240篇 |
武器工业 | 128篇 |
无线电 | 1947篇 |
一般工业技术 | 1203篇 |
冶金工业 | 276篇 |
原子能技术 | 127篇 |
自动化技术 | 1786篇 |
出版年
2024年 | 12篇 |
2023年 | 102篇 |
2022年 | 147篇 |
2021年 | 232篇 |
2020年 | 247篇 |
2019年 | 250篇 |
2018年 | 240篇 |
2017年 | 291篇 |
2016年 | 362篇 |
2015年 | 401篇 |
2014年 | 601篇 |
2013年 | 587篇 |
2012年 | 676篇 |
2011年 | 717篇 |
2010年 | 565篇 |
2009年 | 573篇 |
2008年 | 647篇 |
2007年 | 733篇 |
2006年 | 642篇 |
2005年 | 539篇 |
2004年 | 393篇 |
2003年 | 415篇 |
2002年 | 319篇 |
2001年 | 330篇 |
2000年 | 267篇 |
1999年 | 234篇 |
1998年 | 148篇 |
1997年 | 160篇 |
1996年 | 127篇 |
1995年 | 130篇 |
1994年 | 104篇 |
1993年 | 75篇 |
1992年 | 77篇 |
1991年 | 60篇 |
1990年 | 49篇 |
1989年 | 33篇 |
1988年 | 30篇 |
1987年 | 21篇 |
1986年 | 15篇 |
1985年 | 9篇 |
1984年 | 14篇 |
1983年 | 6篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1963年 | 2篇 |
1959年 | 3篇 |
1957年 | 2篇 |
1956年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 173 毫秒
51.
The design of feedback-linearization and poles-placement controllers for discrete-time non-linear plants, using Input/Output/State measurements only, is typically addressed via indirect design. In this paper we propose the use of a new technique, based on a Virtual Input Direct Design (VID2) approach. The main feature of such a technique is to reduce the control design problem into a standard non-linear mapping approximation problem, without calling for the preliminary construction of an appropriate model of the plant. As compared with the existing methods, the new one requires less computational effort, while taking full advantage of the non-linear approximation software tools already available. In this paper, the new method is described, a simple theoretical analysis is given, and some numerical examples are presented. 相似文献
52.
A. BETTERO M. R. ANGI F. GALIANO C. A. BENASSI 《International journal of cosmetic science》1985,7(1):1-8
To assess ocular irritancy caused by chemical and cosmetic products a reliable method based on evaluation of histamine (Hm) in tears is presented. Hm is measured at picomole levels by HPLC and fluorimetric detection after fluorescamine-HM derivatization. In order to avoid any uncontrolled irritation and stimulation of the conjunctiva during sample collection, a procedure of conjunctiva lavage was developed. A balanced salt solution (50 μl) containing a known amount of Hm-fluorophore as reference standard is instilled in the conjunctiva fornix. After a few seconds 20 μl of tear fluid is collected: 10 μl are immediately analysed and 10 μl after derivatization reaction. In this way it is possible to evaluate tear dilution and to assess Hm content in less than 10 minutes.
In a group of 20 normal subjects Hm has been determined in comparison with that of two volunteers after topical application of 50 μ of 0.2% and 0.4% sodium lauryl sulphate solution. A contact of 30 seconds of the cosmetic ingredient caused an immediate dose-dependent Hm release through a direct cytotoxic damage of cell membranes due to the surfactant action.
Évaluation de l'irritation occulaire due aux cosmétiques par la détermination de l'histamine lacrimale 相似文献
In a group of 20 normal subjects Hm has been determined in comparison with that of two volunteers after topical application of 50 μ of 0.2% and 0.4% sodium lauryl sulphate solution. A contact of 30 seconds of the cosmetic ingredient caused an immediate dose-dependent Hm release through a direct cytotoxic damage of cell membranes due to the surfactant action.
Évaluation de l'irritation occulaire due aux cosmétiques par la détermination de l'histamine lacrimale 相似文献
53.
54.
Analytical solution for the axisymmetric plane strain electroelastic dynamics of a special non-homogeneous piezoelectric hollow cylinder 总被引:1,自引:0,他引:1
By virtue of the introduction of a dependent variable and the separation of variables technique, the axisymmetric plane strain electroelastic dynamic problem of a special non-homogeneous piezoelectric hollow cylinder is transformed to a Volterra integral equation of the second kind about a function with respect to time, which can be solved successfully by means of the interpolation method. Then the solutions of displacements, stresses, electric displacements and electric potential are obtained. The present method is suitable for a piezoelectric hollow cylinder with an arbitrary thickness subjected to arbitrary mechanical and electrical loads. Numerical results are finally presented. 相似文献
55.
56.
57.
58.
59.
选择7种稀土元素:La、Ce、Sm、Eu、Yb、Lu、Y为研究对象,采用高纯稀土氧化物(≥99 99%)为原料,经ICP MS及ICP AES对纯度进行分析后,分别制备成浓度为1000μg mL的稀土溶液标准物质。采用准确、可靠并能溯源的EDTA络合滴定法进行量值核对、均匀性及稳定性检验。对标准物质的不确定度进行了全面的评定。研制的稀土溶液一级标准物质,总不确定度优于0 6%,稳定性达两年以上。 相似文献
60.
R. B. Shaevich 《Measurement Techniques》2006,49(1):75-81
Versions are suggested for resolving the problem of monitoring the accuracy of determining small amounts of components in
samples of substances and materials.
__________
Translated from Izmeritel'naya Tekhnika, No. 1, pp. 52–57, January, 2006. 相似文献