首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   547篇
  免费   0篇
化学工业   108篇
金属工艺   24篇
机械仪表   1篇
建筑科学   3篇
矿业工程   13篇
轻工业   1篇
水利工程   20篇
石油天然气   76篇
无线电   1篇
一般工业技术   132篇
冶金工业   128篇
原子能技术   37篇
自动化技术   3篇
  2005年   11篇
  2004年   28篇
  2003年   9篇
  2002年   13篇
  2001年   11篇
  2000年   3篇
  1999年   2篇
  1998年   26篇
  1997年   9篇
  1996年   17篇
  1995年   8篇
  1994年   7篇
  1993年   12篇
  1992年   17篇
  1991年   16篇
  1990年   14篇
  1989年   10篇
  1988年   7篇
  1987年   15篇
  1986年   14篇
  1985年   9篇
  1984年   8篇
  1983年   12篇
  1982年   9篇
  1981年   18篇
  1980年   16篇
  1979年   17篇
  1978年   21篇
  1977年   22篇
  1976年   27篇
  1975年   20篇
  1974年   14篇
  1973年   14篇
  1972年   9篇
  1971年   12篇
  1970年   12篇
  1969年   12篇
  1968年   9篇
  1967年   12篇
  1966年   7篇
  1965年   4篇
  1964年   6篇
  1963年   1篇
  1962年   3篇
  1958年   4篇
排序方式: 共有547条查询结果,搜索用时 718 毫秒
1.
The crystal structure of [NpO2{OC(NH2)2}5]ClO4·H2O and [NpO2Cl{OC(NH2)2}4] was studied by X-ray diffraction. The electronic absorption spectra of these complexes were recorded. The coordination polyhedron of Np in both complexes is a distorted pentagonal bipyramid. There is no cation-cation interaction of neptunyl cations in these complexes.  相似文献   
2.
The main phase transformations during synthesis of β‐sialon from kaolin of the Prosyanovskii deposit (Ukraine) under test-industrial production conditions have been studied. Sialon was prepared by carbothermal reduction in graphite-tube furnaces in nitrogen. It is shown that the process is characterized by the simultaneous occurrence of several chemical reactions with formation of intermediate phases (Si2ON2, X1‐phase), silicon carbide, and (apart from β‐sialon) sialons based on AlN polytypes. The phase composition of the final product is determined not only by the charge composition but also by the set of production parameters. Results of the work may provide a basis for commercial preparation of sialon powder.  相似文献   
3.
The results of development work on the SVBR-75/100 modular fast reactor cooled by lead–bismuth coolant are presented. The design is based on the experience gained operating reactors in nuclear-powered submarines. The SVBR-75/100 reactor is inherently safe because of its low power, the chemical inertness and high boiling point of the lead–bismuth coolant, and the integrated basin-type arrangement of the first-loop equipment. This eliminates the conflict between the safety and economic requirements that is characteristic of conventional-type reactors. The lower power makes it possible to build the reactor in a factory and deliver the reactor using any form of transportation to the nuclear power plant site. All safety systems operate passively. Most of these systems are used as normal-operating systems. This creates conditions for multipurpose applications of such reactor modules in developed and developing countries.  相似文献   
4.
This article considers a discrete sequential multilevel automated system for recording electron-diffraction patterns. A comparative analysis is presented, along with experimental results that make it possible to evaluate the effectiveness of the technical decisions on which the device is based. The general design of the system is presented. Translated from Izmeritel'naya Tekhnika No. 5, pp. 16–18, May, 1996.  相似文献   
5.
6.
Nuchal screening has the following advantages: Non invasive. First trimester procedure. Results are obtained quickly. 80-90% detection rate for Down's Syndrome.  相似文献   
7.
Using the method of equivalent equations we obtain improved (true) values for the parameters of the spherical shell potential for n-pentane.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 51, No. 4, pp. 529–633, October, 1986.  相似文献   
8.
9.
10.
Conclusions New and effective refractories have been developed whose physicotechnical and working parameters are better than those of existing Soviet and foreign materials. Commercial production of them has been organized.MKFU-83 and KKFU-76 refractories increase mixer lining resistance by substantial factors and reduce the number of repair cycles and the material and labor costs, while increasing the metal output. The refractories are recommended for use in steel-melting processes (electric furnaces and buckets).Translated from Ogneupory, No. 2, pp. 24–26, February, 1991.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号