全文获取类型
收费全文 | 416篇 |
免费 | 11篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 73篇 |
金属工艺 | 14篇 |
机械仪表 | 4篇 |
建筑科学 | 38篇 |
矿业工程 | 1篇 |
能源动力 | 10篇 |
轻工业 | 58篇 |
石油天然气 | 1篇 |
无线电 | 38篇 |
一般工业技术 | 58篇 |
冶金工业 | 99篇 |
原子能技术 | 3篇 |
自动化技术 | 26篇 |
出版年
2022年 | 4篇 |
2021年 | 15篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 13篇 |
2012年 | 13篇 |
2011年 | 13篇 |
2010年 | 21篇 |
2009年 | 8篇 |
2008年 | 16篇 |
2007年 | 11篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 13篇 |
2000年 | 9篇 |
1999年 | 12篇 |
1998年 | 32篇 |
1997年 | 21篇 |
1996年 | 18篇 |
1995年 | 8篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1990年 | 4篇 |
1988年 | 3篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1963年 | 5篇 |
1956年 | 2篇 |
1929年 | 2篇 |
排序方式: 共有427条查询结果,搜索用时 15 毫秒
371.
372.
JM Casasnovas T Stehle JH Liu JH Wang TA Springer 《Canadian Metallurgical Quarterly》1998,95(8):4134-4139
The 3.0-A structure of a 190-residue fragment of intercellular adhesion molecule-1 (ICAM-1, CD54) reveals two tandem Ig-superfamily (IgSF) domains. Each of two independent molecules dimerizes identically with a symmetry-related molecule over a hydrophobic interface on the BED sheet of domain 1, in agreement with dimerization of ICAM-1 on the cell surface. The residues that bind to the integrin LFA-1 are well oriented for bivalent binding in the dimer, with the critical Glu-34 residues pointing away from each other on the periphery. Residues that bind to rhinovirus are in the flexible BC and FG loops at the tip of domain 1, and these and the upper half of domain 1 are well exposed in the dimer for docking to virus. By contrast, a residue important for binding to Plasmodium falciparum-infected erythrocytes is in the dimer interface. The presence of A' strands in both domains 1 and 2, conserved hydrogen bonds at domain junctions, and elaborate hydrogen bond networks around the key integrin binding residues in domain 1 make these domains suited to resist tensile forces during adhesive interactions. A subdivision of the intermediate (I) set of IgSF domains is proposed in which domain 1 of ICAM-1 and previously described I set domains belong to the I1 set and domain 2 of ICAM-1, ICAM-2, and vascular cell adhesion molecule-1 belong to the I2 set. 相似文献
373.
T. Gessner K. Gottfried R. Hoffmann C. Kaufmann U. Weiss E. Charetdinov P. Hauptmann R. Lucklum B. Zimmermann U. Dietel G. Springer M. Vogel 《Microsystem Technologies》2000,6(5):169-174
The present study is focused on the development of a gas sensor for application in a high temperature environment. The sensor
has been realised using thin films prepared on silicon substrates including a high temperature stable heating and wiring system.
TiO2 acts as sensitive layer. Measurements have been carried out in synthetic gas mixtures as well as in gases in a given application.
Neural networks and multivariate data analysis have been used for determining the gas concentrations. The capability to detect
CO, NO
x
, and toluene is shown.
Received: 3 February 2000/Accepted: 3 February 2000 相似文献
374.
J Kitayama MW Carr SJ Roth J Buccola TA Springer 《Canadian Metallurgical Quarterly》1997,158(5):2340-2349
At inflammatory sites in vivo, leukocytes may confront multiple, competing chemoattractive signals. We found significant differences between eosinophils and neutrophils in transendothelial chemotaxis to a chemoattractant diffusing from the lower chamber, when a chemoattractant that binds to another receptor is present at uniform concentration. The transendothelial migration of eosinophils to FMLP, C5a, RANTES, or MCP-3 was totally inhibited by the presence of the homologous chemoattractant, and only RANTES and MCP-3 showed mutual inhibition. C5a and to a lesser extent FMLP chemokinetically stimulated migration to RANTES and MCP-3, without stimulating random migration. Results with neutrophils contrasted. The presence of FMLP not only abrogated neutrophil transmigration to FMLP but also strongly decreased chemotaxis to C5a, IL-8, and Gro-alpha. Similarly, C5a inhibited neutrophil chemotaxis to IL-8 and Gro-alpha. IL-8 almost totally abrogated chemotaxis to Gro-alpha, but Gro-alpha only moderately inhibited chemotaxis to IL-8. Neither IL-8 nor Gro-alpha significantly inhibited transmigration to FMLP or C5a. Actin polymerization in eosinophils and neutrophils was desensitized by the same combinations of chemoattractants that desensitized chemotaxis. We conclude that eosinophils have at least three noninterfering receptor-signal transduction pathways for chemotaxis and actin polymerization. In contrast, the signaling pathways for FMLP, C5a, and IL-8/Gro-alpha in neutrophils are heterologously cross-desensitized, with a hierarchy of resistance to competing signals of FMLP > C5a > IL-8 > Gro-alpha, in agreement with previous results in neutrophils on the Ca2+-mobilizing response. These results may have important implications for the behavior of these cell types in inflammatory sites. 相似文献
375.
Andrew A. Efanov Christian G. Diskus Andreas Stelzer Hartwig W. Thim Kurt Lübke Andreas L. Springer 《电信纪事》1997,52(3-4):219-223
Two different 35 GHz low-cost rf front-end Doppler units suited for automotive applications have been constructed. The homodyne unit consists of both receiving and transmitting corporate-fed microstrip patch array antennas, a microstrip directional coupler, a monolithic GaAs fected oscillator and an integrated single Schottky diode mixer. The autodyne configuration uses only one antenna and the fected as a self-oscillating mixer. Inexpensive microstrip technology has been used which yields a good compromise between cost factor and technical performance. 相似文献
376.
377.
DP Braunstein K Chu KD Egeberg H Frauenfelder JR Mourant GU Nienhaus P Ormos SG Sligar BA Springer RD Young 《Canadian Metallurgical Quarterly》1993,65(6):2447-2454
Fouier-transform infrared (FTIR) difference spectra of several His-E7 and Val-E11 mutants of sperm whale carbonmonoxymyoglobin were obtained by photodissociation at cryogenic temperatures. The IR absorption of the CO ligand shows characteristic features for each of the mutants, both in the ligand-bound (A) state and in the photodissociated (B) state. For most of the mutants, a single A substate band is observed, which points to the crucial role of the His-E7 residue in determining the A substrate spectrum of the bound CO in the native structure. The fact that some of the mutants show more than one stretch band of the bound CO indicates that the appearance of multiple A substates is not exclusively connected to the presence of His-E7. In all but one mutant, multiple stretch bands of the CO in the photodissociated state are observed; these B substates are thought to arise from discrete positions and/or orientations of the photodissociated ligand in the heme pocket. The red shifts of the B bands with respect to the free-gas frequency indicate weak binding in the heme pocket. The observation of similar red shifts in microperoxidase (MP-8), where there is no residue on the distal side, suggests that the photodissociated ligand is still associated with the heme iron. Photoselection experiments were performed to determine the orientation of the bound ligand with respect to the heme normal by photolyzing small fractions of the sample with linearly polarized light at 540 nm. The resulting linear dichroism in the CO stretch spectrum yielded angles alpha > 20 degrees between the CO molecular axis and the heme normal for all of the mutants. We conclude that the off-axis position of the CO ligand in the native structure does not arise from steric constraints imposed by the distal histidine. There is no clear correlation between the size of the distal residue and the alpha of the CO ligand. 相似文献
378.
Leary Mark R.; Springer Carrie; Negel Laura; Ansell Emily; Evans Kelly 《Canadian Metallurgical Quarterly》1998,74(5):1225
One hundred sixty-four participants recounted situations in which their feelings had been hurt (victim accounts) or in which they had hurt another person's feelings (perpetrator accounts) and then completed a questionnaire. Hurt feelings were precipitated by events that connoted relational devaluation, and the victims' distress correlated strongly with feelings of rejection. Victims were typically hurt by people whom they knew well, suggesting that familiarity or closeness played a role. Analyses of the subjective experience revealed that hurt feelings are characterized by undifferentiated negative affect that is often accompanied by emotions such as anxiety and hostility. Victims' responses to the event were related to their attributions for the perpetrators' actions, and hurtful episodes typically had negative repercussions for the relationships between perpetrators and victims. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
379.
Roberts Richard J.; Varney Nils R.; Hulbert James R.; Paulsen Jane S.; Richardson Emily D.; Springer Jane A.; Shepherd Janet Smith; Swan Cynthia M.; Legrand Joseph A.; Harvey John H.; Struchen Margaret A.; Hines Marc E. 《Canadian Metallurgical Quarterly》1990,4(2):65
Investigated the phenomenology of partial seizure-like symptoms in 3 studies. Although the findings from Study 1 with 661 undergraduates and Study 2 with 435 undergraduates demonstrated that normal individuals do report experiencing partial seizure-like phenomena, such symptoms are quite infrequent. Increased levels of symptom reporting were observed in healthy young adults who had experienced various risk factors for cerebral dysfunction (e.g., loss of consciousness due to head trauma, severe febrile illness in adulthood or adolescence). In Study 3, 15 selected brain-injured patients reported a breadth and frequency of partial seizure-like symptomatology that surpassed the limits of normal variability. Findings support the proposition that experiencing of partial seizure phenomena can be conceptualized on a continuum ranging from a healthy, essentially symptom-free state to overt central nervous system (CNS) dysfunction with multiple partial seizure symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
380.
Batuecas E. Contreras-Lisperguer R. Mayo C. Díaz R. Springer C. Pérez F. J. 《Clean Technologies and Environmental Policy》2021,23(5):1415-1430
Clean Technologies and Environmental Policy - E10 is a blend of 10% bioethanol and 90% gasoline that can be used in the engines of most cars without causing damage. Currently for the E10 blend,... 相似文献