全文获取类型
收费全文 | 645611篇 |
免费 | 8258篇 |
国内免费 | 2575篇 |
专业分类
电工技术 | 12527篇 |
技术理论 | 5篇 |
综合类 | 1797篇 |
化学工业 | 100605篇 |
金属工艺 | 26568篇 |
机械仪表 | 19381篇 |
建筑科学 | 15786篇 |
矿业工程 | 3922篇 |
能源动力 | 14982篇 |
轻工业 | 55605篇 |
水利工程 | 7067篇 |
石油天然气 | 15087篇 |
武器工业 | 260篇 |
无线电 | 71270篇 |
一般工业技术 | 126597篇 |
冶金工业 | 117392篇 |
原子能技术 | 14854篇 |
自动化技术 | 52739篇 |
出版年
2021年 | 5516篇 |
2019年 | 5022篇 |
2018年 | 8565篇 |
2017年 | 8456篇 |
2016年 | 9089篇 |
2015年 | 6246篇 |
2014年 | 10412篇 |
2013年 | 28433篇 |
2012年 | 16838篇 |
2011年 | 22567篇 |
2010年 | 17888篇 |
2009年 | 19884篇 |
2008年 | 21041篇 |
2007年 | 20993篇 |
2006年 | 18500篇 |
2005年 | 16698篇 |
2004年 | 15723篇 |
2003年 | 15143篇 |
2002年 | 14892篇 |
2001年 | 15001篇 |
2000年 | 14277篇 |
1999年 | 14550篇 |
1998年 | 33318篇 |
1997年 | 24313篇 |
1996年 | 18813篇 |
1995年 | 14437篇 |
1994年 | 13159篇 |
1993年 | 12866篇 |
1992年 | 9973篇 |
1991年 | 9599篇 |
1990年 | 9655篇 |
1989年 | 9417篇 |
1988年 | 9078篇 |
1987年 | 7846篇 |
1986年 | 8099篇 |
1985年 | 9012篇 |
1984年 | 8506篇 |
1983年 | 8029篇 |
1982年 | 7253篇 |
1981年 | 7664篇 |
1980年 | 7088篇 |
1979年 | 7316篇 |
1978年 | 7187篇 |
1977年 | 7952篇 |
1976年 | 10317篇 |
1975年 | 6464篇 |
1974年 | 6214篇 |
1973年 | 6302篇 |
1972年 | 5415篇 |
1971年 | 4826篇 |
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
991.
V. A. Pilipovich V. L. Malevich G. D. Ivlev V. V. Zhidkov 《Journal of Engineering Physics and Thermophysics》1985,48(2):228-233
On the basis of a numerical solution of the Stefan problem, the dynamics of nanosecond laser annealing of silicon is investigated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 48, No. 2, pp. 306–312, February, 1985. 相似文献
992.
993.
New algorithms for the automatic restoration of antique documents affected by foxing and by yellowing deterioration processes are proposed in the paper. The physical restoration of such objects is both expensive and hard to carry out by nonspecialised library personnel. The proposed algorithms ensure fast and less expensive results, and can be used also by nonqualified operators. Moreover, these techniques improve the performance of optical character recognition operators. 相似文献
994.
An innovative technology for industrial wastewater treatment has been developed. The main focus of the new system is a transformation of persistent organic compounds (biorecalcitrant COD) into a biodegradable fraction, followed by high efficient biological elimination using specialised bacteria's. To fulfill these targets the Aqua-Biomant process integrates two treatment steps: an aerated biological upflow filter and a electrochemical oxidation technique using boron doped-diamond electrodes. The advantages of the process are high efficient COD removal with reduced energy consumption combined with low total residence time. 相似文献
995.
996.
The IGES Model Comparison System (IMCOS) is the first test tool to allow an easy and automatic semantic comparison of CAD models represented in IGES format. By systematically analyzing and comparing entity data and structures of generated and exchanged IGES models, it detects loss of information and functionality resulting from model exchange via IGES processors. IMCOS was designed and implemented as a tabledriven IGES processor to allow external control of the comparison process and full coverage of the current version of IGES (Version 3.0) and future versions. This article presents the basic concepts of IMCOS. The great interest in and discussion of IMCOS have shown the importance of such a test tool. IMCOS may be used as one of several test tools within an overall IGES verification program. 相似文献
997.
A calorimetric measurement technique developed for NASA's Deep Space Network (DSN) transmitters that does not require data on the coolant's thermal parameters is described. Calibration of the measurement system is achieved by measuring the DC input power to the klystron and relating coolant temperature increase to this known power dissipation. Agreement between calorimetric and electrical measurements of total system power was good, the difference being less than 2%. The operation of the system was not greatly affected by the composition of the coolant, which was varied from pure water to 40% ethylene glycol by mass. Good accuracy was also shown at output power levels, which varied over a 3.6:1 range 相似文献
998.
999.
1000.
With the aim of optimizing the performance of Li/Li1+xV3O8 cells, several aspects of cathode preparation have been examined. The influence of synthesis technique, nature and amount of conductive additives, compacting pressure, cathode loading, and particle size, has been investigated. Furthermore, the role played by the solutions on cathode efficiency has been outlined. The formulations which perform best are based on small-sized particles blended with about 20% acetylene black and compacted at very high pressures to improve the contact between particles. Such cathodes can provide high capacities at high rates and good cycling efficiencies. The kinetic loss of capacity, observed during the first few cycles, may be alleviated by choosing solutions with high fluidity and conductivity. 相似文献