全文获取类型
收费全文 | 708篇 |
免费 | 23篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 36篇 |
化学工业 | 145篇 |
金属工艺 | 15篇 |
机械仪表 | 3篇 |
建筑科学 | 17篇 |
能源动力 | 18篇 |
轻工业 | 70篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 71篇 |
一般工业技术 | 106篇 |
冶金工业 | 210篇 |
原子能技术 | 22篇 |
自动化技术 | 18篇 |
出版年
2023年 | 6篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 10篇 |
2015年 | 10篇 |
2014年 | 14篇 |
2013年 | 22篇 |
2012年 | 14篇 |
2011年 | 26篇 |
2010年 | 21篇 |
2009年 | 25篇 |
2008年 | 25篇 |
2007年 | 18篇 |
2006年 | 23篇 |
2005年 | 15篇 |
2004年 | 22篇 |
2003年 | 30篇 |
2002年 | 16篇 |
2001年 | 21篇 |
2000年 | 18篇 |
1999年 | 29篇 |
1998年 | 78篇 |
1997年 | 47篇 |
1996年 | 33篇 |
1995年 | 29篇 |
1994年 | 21篇 |
1993年 | 21篇 |
1992年 | 15篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1972年 | 2篇 |
1962年 | 1篇 |
排序方式: 共有733条查询结果,搜索用时 15 毫秒
91.
Operation management is an essential technology for the “OTV (Orbital Transfer Vehicle) Network” which has been proposed as a promising space transportation infrastructure for the next century. In addition to the nominal mode scheduling, the management system must quickly re-make the schedule in the case of failures of some system elements, inputs of urgent missions or mission alterations. This paper analyses this management as a new control problem, and proposes a distributed artificial intelligence-type system architecture to deal with it. The effectiveness of the system has been verified by simulation studies assuming practical problem settings. 相似文献
92.
A new idea for the development of ultra high strength steels by utilizing the spinodal decomposition of the Fe-Mo binary system is proposed. The idea comprises the restraint of the brittleness of the Fe-Mo alloy by reducing the Mo-content necessary to spinodal decomposition and by microstructure refining such as grain refining, subgrain refining etc; the former is realized by the alloying with some elements which, in general, have a tendency towards ordering (i.e., negative interchange energy between the nearest neighbour atoms) when combined with iron, and the latter by thermomechanical treatment and/or cold rolling. On the basis of the idea, that hidden properties indispensable to high strength materials are successfully drawn from the Fe-Mo alloy; we have obtained a 4GPa grade high tensile steel of Fe-Mo-Co-V. This idea is sure to contribute new suggestions to the development of high strength materials. 相似文献
93.
Molecular determinants of calcium-dependent inactivation in cardiac L-type calcium channels 总被引:1,自引:0,他引:1
We investigated the nature and structural requirements for Ca(2+)-dependent inactivation of cardiac L-type Ca2+ channel. Investigation of subunit requirements indicates that the interaction of alpha 1 subunit with ancillary subunits, especially beta subunit, is important for this property. Replacement of the putative cytoplasmic regions of the cardiac alpha 1 subunit with skeletal muscle counterparts eliminates Ca(2+)-dependent inactivation, indicating that the site regulated by Ca2+ resides in the cytoplasmic region of the alpha 1 subunit. Deletion of the carboxy-terminal region of the cardiac alpha 1 subunit does not eliminate this property, suggesting that the modulation by protein kinase A may not be involved in this mechanism. Single amino acid substitution that strongly reduces Ca2+ selectivity of Ca2+ channels also eliminates Ca(2+)-dependent inactivation, suggesting the close link between the ion selectivity and Ca(2+)-dependent inactivation. 相似文献
94.
T Takahashi H Ishikura K Iwai C Takahashi H Kato T Tanabe T Yoshiki 《Canadian Metallurgical Quarterly》1993,36(2):76-82
The permanent pancreas carcinoma cell line, PCI-24, was developed in order to analyse cytokine regulation on pancreas carcinoma and lymphokine-activated killer (LAK) cell interaction. PCI cells expressed ICAM-1 and HLA-ABC, but not HLA-DR antigens. PCI cells showed augmented ICAM-1 and HLA-ABC expression when incubated with interferon gamma (IFN gamma) and tumour necrosis factor alpha. A similar but weak augmentary effect on the HLA-ABC and ICAM-1 surface expression was seen with interleukin-1 beta treatment. Natural attachment of LAK to PCI cells was augmented by recombinant IFN gamma in close association with ICAM-1 up-regulation on PCI cells. In addition, natural attachment was significantly inhibited by anti-LFA-1 and anti-ICAM-1 antibody treatments. Cytotoxicity of the LAK cells against PCI cells was also significantly inhibited with the same treatment. Thus, the attachment of LAK cells to PCI cells through LFA-1/ICAM-1 molecules appeared to be essential for the cytotoxicity for PCI cells. Pretreatment of PCI cells, but not of LAK cells, with IFN gamma or other cytokines resulted in a decrease of susceptibility for LAK cell cytotoxicity. The decreased susceptibility inversely correlated with HLA-ABC expression on the PCI cells. The collective evidence indicates that, although LAK cell attachment to pancreas carcinoma cells through the LFA-1/ICAM-1 molecule is augmented by IFN gamma, IFN gamma treatment of pancreas carcinoma cells reduces LAK cell cytotoxicity possibly through an increase in HLA-ABC or a regulation of molecules closely associated to HLA-ABC expression. 相似文献
95.
96.
Describes a new program that combines clinical/community psychology with training in public health and business administration. The discussion includes factors underlying the planning process, the contribution of its component parts to the program's overall goals, extramural support, and the potential marketplace for graduates. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
97.
A rare case of downward displacement of the left kidney caused by marked development of an ectopic ovarian cyst in the left subphrenic region is presented. Exact diagnosis could not be made preoperatively but a satisfactory result was obtained by removal of the cyst. Histological diagnosis of the tumor was serous cystadenoma arising from the left ovary. 相似文献
98.
Kazuo Kawasaki Daizo Yonemura Jhoji Tanabe Hirohiko Nakazato Izumi Kawaguchi Yutaka Shirao 《Color research and application》1982,7(2):165-167
The off response of the P III component isolated by aspartate in the human eyecup in vitro showed an initial rapid decay followed by a slow decay. The rapid decay in the human ERG originates mainly in cones. The rapid decay was also observed in human subjects. The spectral sensitivity curve of the rapid decay was found to be shifted toward short wavelengths in all nine protanopes tested. In these cases of protanopia, anomalous cone functions were indicated. 相似文献
99.
100.
Shinya Otsuka Toyokazu Sano Zensaku Kozuka 《Metallurgical and Materials Transactions B》1980,11(2):313-319
Modified coulometric titrations on the galvanic cell;O in liquid Tl or In/ZrO2(+CaO)/Air, Pt, were performed at 973, 1073, and 1173 K to determine the oxygen activities in liquid thallium and liquid indium.
The standard Gibbs energies of solution of oxygen in liquid thallium and liquid indium for l/2 O2 →O (1 at. pct) were determined respectively to be δG‡(in Tl) = -22000 + 0.74T (±300) cal/g-atom = -92000 + 3.10T (±1300) J/g-atom, δG‡(in In) = -42450+ 3.30T (±350) cal/g-atom = -177600 + 13.8T (±1500) J/g-atom, where the reference state for dissolved oxygen was an infinitely dilute solution. It was reconfirmed that
the apparent initial oxygen concentration observed in the range of very low oxygen concentration in liquid metal was attributed
to the oxygen released from the solid electrolyte. 相似文献