全文获取类型
收费全文 | 834篇 |
免费 | 15篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 33篇 |
化学工业 | 226篇 |
金属工艺 | 8篇 |
机械仪表 | 16篇 |
建筑科学 | 55篇 |
矿业工程 | 4篇 |
能源动力 | 19篇 |
轻工业 | 133篇 |
水利工程 | 13篇 |
无线电 | 31篇 |
一般工业技术 | 98篇 |
冶金工业 | 108篇 |
原子能技术 | 6篇 |
自动化技术 | 102篇 |
出版年
2021年 | 9篇 |
2019年 | 7篇 |
2016年 | 15篇 |
2015年 | 14篇 |
2014年 | 14篇 |
2013年 | 24篇 |
2012年 | 32篇 |
2011年 | 32篇 |
2010年 | 21篇 |
2009年 | 22篇 |
2008年 | 30篇 |
2007年 | 38篇 |
2006年 | 24篇 |
2005年 | 26篇 |
2004年 | 27篇 |
2003年 | 20篇 |
2002年 | 16篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 20篇 |
1998年 | 15篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 15篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 15篇 |
1990年 | 16篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1986年 | 9篇 |
1985年 | 7篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 7篇 |
1975年 | 14篇 |
1974年 | 11篇 |
1973年 | 18篇 |
1972年 | 11篇 |
1971年 | 10篇 |
1970年 | 16篇 |
1969年 | 9篇 |
1968年 | 7篇 |
1967年 | 7篇 |
排序方式: 共有852条查询结果,搜索用时 15 毫秒
31.
Dierdorff Erich C.; Bell Suzanne T.; Belohlav James A. 《Canadian Metallurgical Quarterly》2011,96(2):247
We examined the influences of different facets of psychological collectivism (Preference, Reliance, Concern, Norm Acceptance, and Goal Priority) on team functioning at 3 different performance depictions: initial team performance, end-state team performance, and team performance change over time. We also tested the extent to which team-member exchange moderated the relationships between facets of psychological collectivism and performance change over time. Results from multilevel growth modeling of 66 teams (N = 264) engaged in a business simulation revealed differential effects across facets of psychological collectivism and across different performance measurements. Whereas facets concerned with affiliation (Preference and Concern) were positively related to initial team performance, reliance was negatively related to initial team performance. Goal Priority was a strong predictor of end-state performance. Team-member exchange moderated the relationship between performance change and 3 of the 5 facets of psychological collectivism (Preference, Reliance, Norm Acceptance). Implications for team composition and team training are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
32.
Yusuf Tanrikulu Ewgenij Proschak Dr. Tim Werner Tim Geppert Nickolay Todoroff Alexander Klenner Tim Kottke Kerstin Sander Erich Schneider Dr. Roland Seifert Prof. Dr. Holger Stark Prof. Dr. Timothy Clark Prof. Dr. Gisbert Schneider Prof. Dr. 《ChemMedChem》2009,4(5):820-827
A new pseudoreceptor modeling method (PRPS) was applied to the refinement of a homology model of the human histamine H4 receptor (H4R), the prediction of a ligand binding site, and virtual screening. Retrieval of two new H4R ligands demonstrates the biological relevance of the pseudoreceptor model and provides a means for finding new hits and leads in the early phases of drug discovery.
33.
Karla Čech Barabaszová Sylva Holešová Marianna Hundáková Erich Pazdziora Michal Ritz 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(4):986-995
Polyethylene (PE) nanocomposites with the zinc oxide-nanoparticles/vermiculite nanofiller were prepared in two-steps. In first step, the ZnO-np/V nanofiller were prepared by the mechanochemical method followed by a heat treatment at 650?°C for 90 min. In second step, this nanofiller was used in concentration 3, 6, 10 and 15 wt% for PE nanocomposites preparation via melt compounding technique, the nanocomposites plates were pressed. The particles morphology of the ZnO-np/V nanofiller, arrangement of the ZnO-np/V nanofiller and surface of the PE plates were studied using scanning electron microscopy, optical light microscopy and atomic force microscopy. The surface roughness of the PE plates was evaluated from AFM measurements. Structural changes of the ZnO-np/V nanofiller in PE nanocomposites were monitored using X-ray diffraction analysis and Fourier transform infrared analysis. The gradual and long-term antibacterial effect of PE nanocomposites was tested on the Gram positive bacteria E. faecalis by counting the colony forming units number. 相似文献
34.
P.A.J. Donkers H.P. Huinink S.J.F. Erich N.J.W. Reuvers O.C.G. Adan 《Progress in Organic Coatings》2013
Coatings are used in a variety of applications. Last decades more and more coating systems are transforming from solvent to waterborne coating systems. In this study the influence of pigments on the water permeability of a waterborne coating system is studied, with special interest in the possible interfacial layer of additives around the pigments. In our study an acrylate based binder is mixed with different glass sphere concentrations and sizes. Subsequently, the coating permeability is studied through wet-cup experiments and water uptake in the coating, either on a glass substrate or on wood, is monitored with NMR. These experiments show that water is absorbed more quickly by coatings containing glass spheres. From the experimental results it can be concluded that an interface layer around the pigment particles facilitates water migration and increases the effective diffusion. A modification of the effective medium theory is used to describe the observation and good agreement between experiments and theory is obtained. Both theory and experiment show that in a coating a layer around the pigments facilitates water transport and increases the effective diffusion constant. 相似文献
35.
A failure mechanism of submarine landslides based on the phenomenon of shear band propagation has been investigated using
the energy balance approach. Dynamic analysis includes inertia effects in the sliding layer and viscous resistance of the
water, but ignores elastic and plastic wave propagation in the sliding layer. The resulting differential equation has been
solved numerically. Analytical approximation of this numerical solution provides a convenient basis for the parametric and
sensitivity studies. The solution allows assessing the velocity and acceleration of both the landslide and the shear band
at the moment when the slide fails due to the limiting equilibrium (i.e., the initial post-failure velocity). The effects
of the initial landslide velocity on the tsunami wave height are discussed and validated for a number of landslide examples. 相似文献
36.
Sorantin E Halmai C Erdöhelyi B Palágyi K Nyúl LG Ollé K Geiger B Lindbichler F Friedrich G Kiesler K 《IEEE transactions on medical imaging》2002,21(3):263-273
PURPOSE: Demonstration of a technique for three-dimensional (3-D) assessment of tracheal-stenoses, regarding site, length and degree, based on spiral computed tomography (S-CT). PATIENTS AND METHODS: S-CT scanning and automated segmentation of the laryngo-tracheal tract (LTT) was followed by the extraction of the LTT medial axis using a skeletonization algorithm. Orthogonal to the medial axis the LTT 3-D cross-sectional profile was computed and presented as line charts, where degree and length was obtained. Values for both parameters were compared between 36 patients and 18 normal controls separately. Accuracy and precision was derived from 17 phantom studies. RESULTS: Average degree and length of tracheal stenoses was found to be 60.5% and 4.32 cm in patients compared with minor caliber changes of 8.8% and 2.31 cm in normal controls (p < 0.0001). For the phantoms an excellent correlation between the true and computed 3-D cross-sectional profile was found (p < 0.005) and an accuracy for length and degree measurements of 2.14 mm and 2.53% respectively could be determined. The corresponding figures for the precision were found to be 0.92 mm and 2.56%. CONCLUSION: LTT 3-D cross-sectional profiles permit objective, accurate and precise assessment of LTT caliber changes. Minor LTT caliber changes can be observed even in normals and, in case of an otherwise normal S-CT study, can be regarded as artifacts. 相似文献
37.
Steinle ED Mitchell DT Wirtz M Lee SB Young VY Martin CR 《Analytical chemistry》2002,74(10):2416-2422
This paper describes synthetic micropore and nanotube membranes that mimic the function of a ligand-gated ion channel; that is, these membranes can be switched from an "off" state (no or low ion current through the membrane) to an "on" state (higher ion current) in response to the presence of a chemical stimulus. Ion channel mimics based on both microporous alumina and Au nanotube membranes were investigated. The off state was obtained by making the membranes hydrophobic by chemisorbing either a C18 silane (alumina membrane) or a C18 thiol (Au nanotube membrane). Water and electrolyte are forbidden from entering these very hydrophobic pores/nanotubes. The transition to the on state was induced by the partitioning of a hydrophobic ionic species (e.g., a drug or a surfactant) into the membrane. The membrane switches to the on state because at a sufficiently high concentration of this ionic analyte species, the pores/nanotubes flood with water and electrolyte. A pH-responsive membrane was also prepared by attaching a hydrophobic alkyl carboxylic acid silane to the alumina membrane. 相似文献
38.
39.
Erich Kutzer 《Zeitschrift für Jagdwissenschaft》1969,15(4):172
Ohne Zusammenfassung 相似文献
40.
Helena Windemann Urs Müller und Erich Baumgartner 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1973,153(1):17-22
Zusammenfassung Die isoelektrische Fokussierung einer wasserlöslichen Proteinfraktion von Hart- und Weichweizen aus Teigwarenprodukten wird mit der bisher üblichen disk-elektrophoretischen Trennmethode verglichen. Die Elektrofokussierung liefert im Gegensatz zur Disk-Elektrophorese auch bei Anwesenheit von Ei-Proteinen sowie nach vorgängiger Hitzedenaturierung der Proteine zuverlässige und genaue Resultate. Im weiteren wird zur besseren Auftrennung und Charakterisierung der wasserlöslichen Proteinfraktion eine zweidimensionale Trennmethode (isoelektrische Fokussierung und anschließende Elektrophorese) beschrieben.
Isoelectric focusing and two-dimensional separation of watersoluble protein fraction of hard and soft wheat from macaroni
Summary The isoelectric focusing of water-soluble protein fraction of hard and soft wheat from macaroni are compared with the disc electrophoresic separation methods. Electrofocusing produced more trustworthy and exacter results in the presence of egg proteins as well for heat-denaturated proteins. Further is described a better separation and characterisation of a water-soluble protein fraction using a two-dimensional system involving isoelectric focusing in the first dimension followed by electrophoresis in the second.相似文献