全文获取类型
收费全文 | 450302篇 |
免费 | 6987篇 |
国内免费 | 1408篇 |
专业分类
电工技术 | 7870篇 |
综合类 | 352篇 |
化学工业 | 68417篇 |
金属工艺 | 17188篇 |
机械仪表 | 14355篇 |
建筑科学 | 9815篇 |
矿业工程 | 2244篇 |
能源动力 | 12421篇 |
轻工业 | 35217篇 |
水利工程 | 4720篇 |
石油天然气 | 8091篇 |
武器工业 | 23篇 |
无线电 | 51769篇 |
一般工业技术 | 90868篇 |
冶金工业 | 86247篇 |
原子能技术 | 9380篇 |
自动化技术 | 39720篇 |
出版年
2022年 | 2985篇 |
2021年 | 4924篇 |
2020年 | 3814篇 |
2019年 | 4698篇 |
2018年 | 8273篇 |
2017年 | 8219篇 |
2016年 | 8755篇 |
2015年 | 5629篇 |
2014年 | 8803篇 |
2013年 | 23319篇 |
2012年 | 14137篇 |
2011年 | 17717篇 |
2010年 | 14178篇 |
2009年 | 15524篇 |
2008年 | 16103篇 |
2007年 | 15626篇 |
2006年 | 13734篇 |
2005年 | 12178篇 |
2004年 | 11540篇 |
2003年 | 11338篇 |
2002年 | 10622篇 |
2001年 | 10266篇 |
2000年 | 9657篇 |
1999年 | 10167篇 |
1998年 | 27818篇 |
1997年 | 18878篇 |
1996年 | 14216篇 |
1995年 | 10353篇 |
1994年 | 9077篇 |
1993年 | 9108篇 |
1992年 | 6291篇 |
1991年 | 5937篇 |
1990年 | 5925篇 |
1989年 | 5561篇 |
1988年 | 5268篇 |
1987年 | 4610篇 |
1986年 | 4515篇 |
1985年 | 5064篇 |
1984年 | 4623篇 |
1983年 | 4151篇 |
1982年 | 3837篇 |
1981年 | 3938篇 |
1980年 | 3616篇 |
1979年 | 3464篇 |
1978年 | 3456篇 |
1977年 | 3994篇 |
1976年 | 5365篇 |
1975年 | 2938篇 |
1974年 | 2741篇 |
1973年 | 2811篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
991.
992.
I. F. Kurunov V. N. Loginov S. S. Lyapin N. S. Polyakov V. N. Titov 《Metallurgist》2007,51(7-8):425-433
The use of schungite as a partial replacement for coke is practiced in Russia at a number of metallurgical plants, both in
the production of foundry iron (its primary use) and in making conversion pig iron. The largest amount of coke is replaced
when foundry iron is being made, the replacement coefficient in this case having a value within the range 0.8–1.3. Studies
that included continuous monitoring of the temperature of the carbon blocks in blast furnaces with volumes of 1719, 3200,
and 5580 m3 unambiguously demonstrate that the thickness of the slag crust in blast furnaces increases with the use of schungite. Protecting
the lining of the hearth through the use of schungite is also accompanied by a decrease in coke consumption.
__________
Translated from Metallurg, No. 8, pp. 53–57, August, 2007. 相似文献
993.
994.
Radioimmunoassay was employed to examine distribution of antigenic structures of bovine serum albumin (BSA), absorbed by the gastrointestinal tract, in the blood serum and organs of intact rats. It was shown that 3 h after administering 3H-BSA an appreciable amount of its antigenic structures could be identified in the blood serum, liver, spleen, and carcass of the animals. The total amount of antigenic determinants of BSA which got into the internal environment of the body from the intestine amounted to about 0.2% of the dose administered. The highest specific content of antigenic structures of BSA supplied via the intestinal barrier was detected in the spleen. 相似文献
995.
Comparative studies on Ar and He closed-cycle MHD power plants combined with fossil fuel are performed. The sizes of a regenerative heat exchanger and a boiler are expected to be smaller for He than for Ar. The pressure loss of a working gas in a regenerative heat exchanger is reduced for He. The purification subsystem for He is expected to be more compact and economical than that for Ar; but a larger compressor is required for He than for Ar. 相似文献
996.
997.
998.
B. S. Bokshtein D. V. Vaganov S. N. Zhevnenko 《The Physics of Metals and Metallography》2007,104(6):564-570
Surface tension of pure copper and its alloys with Sn has been measured at 1000°C in a hydrogen atmosphere. Surface tension of a free surface equaled 1.81 N/m for pure copper, and 1.55, 1.38, and 1.28 N/m for the alloys with 0.05, 0.22, and 0.33 at % Sn, respectively; surface tension at grain boundaries equaled 0.5 N/m for pure copper, and 0.36, 0.3, and 0.23 N/m for the alloys, respectively. Based on these data, the concentration dependence of tin absorption at a free surface and grain boundaries has been calculated. Parameters of Sn absorption at grain boundaries and a free surface of copper have been compared with those of Sb and Bi. 相似文献
999.
S. Mändl 《Surface & coatings technology》2007,201(15):6833-6838
PIII is a powerful method to obtain hard and wear resistant surface on Ti alloys and NiTi by oxygen or nitrogen implantation. By adjusting the temperature, treatment time and heating regime, different phase compositions and layer thickness can be obtained. Depending on the specific system, a strong influence of the resulting microstructure on the wear and fatigue properties was observed. By considering these restrictions, successful animal tests can be designed and executed, as shown in this review article. 相似文献
1000.
Ackerman Steven J.; Hilsenroth Mark J.; Knowles Eric S. 《Canadian Metallurgical Quarterly》2005,42(2):225
The present study examines the concurrent and predictive relationships between therapist psychodynamic-interpersonal activity and therapist-rated alliance. Ratings from 45 patient and therapist dyads engaged in short term psychodynamic psychotherapy from a point early (3rd or 4th session) and late (the session at which 90% of the treatment was completed) in treatment were used. The results suggest that therapists who have positive views of the alliance early in treatment also have positive views of the alliance later in treatment. Therapists who used psychodynamic-interpersonal activities early in treatment also made use of psychodynamic-interpersonal activities later in treatment. Moreover, the use of psychodynamic-interpersonal activities early in treatment was positively related to both global and specific aspects of therapist-rated alliance late in treatment. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献