全文获取类型
收费全文 | 3423篇 |
免费 | 36篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 122篇 |
化学工业 | 401篇 |
金属工艺 | 1582篇 |
机械仪表 | 37篇 |
建筑科学 | 29篇 |
矿业工程 | 2篇 |
能源动力 | 52篇 |
轻工业 | 100篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 267篇 |
一般工业技术 | 278篇 |
冶金工业 | 425篇 |
原子能技术 | 58篇 |
自动化技术 | 105篇 |
出版年
2023年 | 8篇 |
2022年 | 17篇 |
2021年 | 18篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 16篇 |
2017年 | 17篇 |
2016年 | 37篇 |
2015年 | 15篇 |
2014年 | 41篇 |
2013年 | 122篇 |
2012年 | 105篇 |
2011年 | 97篇 |
2010年 | 67篇 |
2009年 | 110篇 |
2008年 | 132篇 |
2007年 | 110篇 |
2006年 | 99篇 |
2005年 | 84篇 |
2004年 | 70篇 |
2003年 | 109篇 |
2002年 | 129篇 |
2001年 | 122篇 |
2000年 | 97篇 |
1999年 | 126篇 |
1998年 | 249篇 |
1997年 | 209篇 |
1996年 | 163篇 |
1995年 | 103篇 |
1994年 | 104篇 |
1993年 | 160篇 |
1992年 | 152篇 |
1991年 | 137篇 |
1990年 | 50篇 |
1989年 | 41篇 |
1988年 | 32篇 |
1987年 | 31篇 |
1986年 | 37篇 |
1985年 | 35篇 |
1984年 | 40篇 |
1983年 | 24篇 |
1982年 | 15篇 |
1981年 | 22篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1976年 | 15篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 5篇 |
排序方式: 共有3462条查询结果,搜索用时 31 毫秒
31.
32.
33.
Masahide Hojo Yasunori Mitani Toshifumi Ise Kiichiro Tsuji 《Electrical Engineering in Japan》2002,138(3):43-51
The advancement of power electronics technologies has significantly developed the power system stabilizing controllers. Quantitative as well as qualitative evaluation of their effectiveness in power systems is a matter of great importance for the feasibility investigation of these apparatus. In this paper, the possible control region of FACTS controllers with series and/or shunt configuration in a single machine to infinite bus system is formulated in the powerangle curve with a set of algebraic equations. The effectiveness of TCPST (Thyristor‐Controlled Phase Shifting Transformer), SSSC (Static Synchronous Series Compensator), and TCSC (Thyristor‐Controlled Series Compensator) for the improvement of the transient stability is evaluated quantitatively as a numerical example. The correctness of the proposed method has been confirmed by analysis based on the electromagnetic transients simulation with a detailed system model. © 2001 Scripta Technica, Electr Eng Jpn, 138(3): 43–51, 2002 相似文献
34.
35.
36.
37.
38.
Ti wire electrodes were immersed in acidic solutions containing H2SO4 and HCl of various concentrations at 353 K to evaluate corrosion rate by measurement of electric resistance change (resistometry). Addition of hydrochloric acid to sulphuric acid solution promoted depassivation of Ti. After depassivation, the immersion potential dropped to the hydrogen evolution potential and a hydride layer was formed on the surface. The hydride layer dissolved continuously in the acidic solution. SEM observation showed that Ti wires dissolved almost uniformly in the early stage and that the dissolution then trace became irregular due to nonuniform growth of the hydride layer. Dissolution rate of a Ti wire was estimated almost accurately by resistometry. 相似文献
39.
H Yasoshima K Uematsu K Sakurai Y Ueno K Hori N Kanazawa T Tanaka N Yamanaka E Okamoto 《Canadian Metallurgical Quarterly》1993,43(12):783-789
A case of primary carcinoid tumor arising in the liver of a 69 year old woman with no endocrine symptoms is reported. Histopathologically, the tumor was diagnosed initially as a hepatocellular carcinoma in the biopsy specimen, and was shown subsequently to be a carcinoid tumor, demonstrating diffuse positive staining with Grimelius method. Mucin stained with periodic acid-Schiff (PAS), alcian-blue, and mucicarmine, and was shown partially in the glandular structures. Immunohistochemically, most of the tumor cells stained positively for chromogranin-A, epithelial membrane antigen (EMA) and neuron specific enolase (NSE). Ultrastructural examination revealed electron-dense core granules, measuring 40-120 nm in diameter in some of the tumor cells. Intensive and careful searches pre- and post-operatively revealed no other primary source of tumor other than the liver. The patient was reported well with no symptoms 3 1/2 years after the operation. This case is considered to be a primary hepatic carcinoid tumor. The recent literature is reviewed, and the possible histogenesis of hepatic carcinoid tumor is discussed. 相似文献
40.