全文获取类型
收费全文 | 820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 | 219篇 |
金属工艺 | 8篇 |
机械仪表 | 17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 | 12篇 |
无线电 | 32篇 |
一般工业技术 | 94篇 |
冶金工业 | 106篇 |
原子能技术 | 5篇 |
自动化技术 | 101篇 |
出版年
2019年 | 7篇 |
2016年 | 15篇 |
2015年 | 14篇 |
2014年 | 13篇 |
2013年 | 24篇 |
2012年 | 33篇 |
2011年 | 30篇 |
2010年 | 21篇 |
2009年 | 22篇 |
2008年 | 29篇 |
2007年 | 36篇 |
2006年 | 24篇 |
2005年 | 26篇 |
2004年 | 27篇 |
2003年 | 20篇 |
2002年 | 15篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 19篇 |
1998年 | 14篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 16篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 15篇 |
1990年 | 16篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 9篇 |
1985年 | 7篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 7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838条查询结果,搜索用时 0 毫秒
1.
Concluding remarks With this brief exposition of the areas covered in this special double issue on Eurotra, we shall now conclude our introduction. We hope that the volume will achieve its goals, as outlined above, at least to some extent. Certainly, much more could be said about a wide range of topics which have been covered in the lifetime or the project so far. For instance, these article, mainly written by linguists, deliberately neglect the software implementation and environment aspects of the prototype Eurotra Translation System, as well as a number of peripheral tools and components of the system that are available to the user, such as lexical data bases, text-handling mechanisms and the like. The reader interested in aspects of this kind is referred to Raw et al. 1989 for a very brief introduction, and to the Eurotra software team at the Commission of the European Communities (DG XIII, Luxembourg) for more details. However, one goal that we do hope to come close to achieving is to give a fair overview of the Eurotra linguistic theory of translation and the mainstream and sideline formalisms expressing variant versions of it. If we have come anywhere near achieving that, our gratitude is due to the numerous Eurotra colleagues who have supported us in preparing this volume, and to the editor of this journal. 相似文献
2.
A method for the determination of carbon black fillers in peroxide vulcanizates or sulfur vulcanizates of natural rubber (NR, cis-1,4-polyisoprene) by metathesis degradation with 1-octene was developed using the catalyst WCl6? (C2H5)3Al2Cl3. The carbon black was separated from the reaction mixture by centrifuging and determined by weighing. In this connection, investigations were also performed with the catalyst WCl6? C2H5Al2Cl3 which was less suitable for filler determination. The rate of degradation of crosslinked NR with (E)-4-octene was measured. Metathesis reactions of 2-methyl-2-pentene (low-molecular-weight model compound of NR) with 7-tetradecene showed the importance of double bond shift for the degradation of NR. 相似文献
3.
4.
5.
Blanchard Kimberly A.; Morgenstern Jon; Morgan Thomas J.; Lobouvie Erich W.; Bux Donald A. 《Canadian Metallurgical Quarterly》2003,17(4):328
Negative consequences are an important component of the substance use change process, yet no standardized measure exists to assess consequences of use. This study evaluated the psychometric properties of the Inventory of Drug Use Consequences, a self-report measure assessing drinking and drug use consequences. Participants (N=252) were assessed at entry into outpatient substance abuse treatment. Items loaded strongly on 1 factor, and internal consistency of the total scale was high. Fifteen items with the highest correlations with the total scale were chosen to represent the construct. The shortened measure exhibited good internal consistency, convergent and discriminant validity, and detected change over time and may be the measure of substance use consequences that is lacking in the field. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Erich Bergmann 《真空研究与实践》1993,5(3):173-178
The hot filament supported high current discharge can be used with various process steps. During the heating cycle, intense electron bombardment provides a soft and efficient energy source. In triode etching the high plasma density improves the throwing power and reduces the arcing problem on oxide inclusions from preceding grinding steps. For the coating cycle the high current density can be fitted into different deposition processes. Activated reactive ion plating is done with a high voltage electron beam gun. But one can also combine the high current density plasma with a magnetron to produce a high plasma density on the substrate and solve the problems of reactivity of this vapor source. Alternatively the high current density plasma can also be used to drive a CVD-reaction. Several of these processes can be combined to hybrid deposition technologies. A few examples of coating realisations and performance in the different processes will be given. 相似文献
7.
Ilkka Kuorinka Hannu Alaranta Ilkka Erich 《International Journal of Industrial Ergonomics》1995,15(6):437-446
During the years 1986–1989 The Finnish Work Environment Fund initiated a multicenter, intervention study (programme) to prevent musculoskeletal disorders at work. The programme consisted of four different projects comprising methodological, epidemiological, and interventive themes. The main results were as follows: (1) More than half of the occupational physiotherapists and physicians involved in the project felt that they did not have adequate training for testing the performance capacity of the musculoskeletal system. Several of the most commonly used musculoskeletal tests had either poor validity in predicting future musculoskeletal troubles or had poor reliability. (2) A controlled intervention study showed that active training of neck-shoulder muscles can prevent musculoskeletal troubles, even more than ergonomic actions. (3) It is possible to reduce sick-leave due to low-back disorders by intervention measures directed toward both the work (environment, tools) and the workers (working methods, positive attitude to work, preparedness to keep fit). (4) The identification of ergonomic hazards with the help of teamwork proved to be feasible. The practical improvements, however, were difficult to implement in the prevailing conditions. Some of the improvements increased the work load and the stress of the workers. This aspect needs further consideration. 相似文献
8.
Werner Strohmaier Henning Klostermeyer Paul Deuritz Erich Windhab 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1992,194(6):531-535
Summary Current texture-measuring instruments and a recently developed measuring method (two-dimensional measuring of the force necessary to spread a sample) were compared in measuring the spreadability of processed cheese. How far subjective assessment by a qualified panel correlates with the instrumental results in determining spreadability and firmness was also investigated. Samples of processed cheese with various consistencies were measured by an Universal testing machine, a buttermeasuring instrument (DIN 10331), a rotational-type rheometer (oscillation mode) and a two-dimensional force measuring instrument. The evaluation of the results shows that an oscillating rheometer is most suitable to measure the spreadability of processed cheese; the correlation coefficient (r) between the dynamic Weissenberg number, calculated from parameters of the rheometer, and the subjective judgement by the panel wasr=0.91. For the determination of firmness the two-dimensional force measuring instrument is most suitable. The correlation coefficient between the parameter tangential energy (S
t) and the sensorially evaluated firmness wasr=0.95.
Vergleich verschiedener Bestimmungsmethoden für die Streichfähigkeit und Festigkeit von Schmelzkäse
Zusammenfassung Verschiedene gebräuchliche Meßinstrumente und ein neu entwickeltes Gerät zur zweidimensionalen Messung der Kräfte, die zum Ausstreichen einer Probe erforderlich sind, wurden vergleichend zur Charakterisierung der Streichfähigkeit von Schmelzkäse erprobt. Dabei wurde auch geprüft, inwieweit die subjektiven Beurteilungen eines qualifizierten Prüferpanels mit den Meßwerten für Streichfähigkeit und Festigkeit korrelierten. Gemessen wurde mit einer Universalprüfmaschine, dem Butterprüfgerät (DIN 10331), einem Rotationsrheometer und mit dem zweidimensional registrierenden Kraftmeßgerät. Dabei zeigte sich, daß das Rheometer im oscillierenden Modus die Streichfähigkeit am besten zu charakterisieren vermag. Die Korrelation zwischen den Rheometerwerten, berechnet als dynamische Weissenbergzahl, und den sensorisch ermittelten Werten für die Streichfähigkeit betrugr=0,91. Zur Bestimmung der Festigkeit ist das zweidimensional registrierende Kraftmeßgerät am besten geeignet, was sich in einem Korrelationskoeffizienten vonr=0,95 zwischen dem ParameterS t und den im Sensoriktest ermittelten Werten für dieFestigkeit ausdrückt.相似文献
9.
Erich N. Grossman 《Journal of Infrared, Millimeter and Terahertz Waves》1987,8(10):1293-1312
We analyze the performance as a terahertz-frequency modulator of a small-area Schottky diode mounted in a corner-cube antenna. The analysis includes the effects of carrier inertia and dielectric relaxation as modeled by Champlin and Eisenstein (1978). It also includes the effect of the vanishing of the depletion region above the flat-band potential, as modeled by Crowe and Mattauch (1986). Our baseline calculation refers to a 1.4 μm diameter diode (Univ. of Virginia batch no. 1E12) operated at a carrier frequency of 2.52 THz and a modulation frequency of 8 GHz, as was used in the experiments of Watson, Grossman, and Phillips (1988). The effects on reflectivity modulation, and therefore on sideband-generation efficiency, of varying the diode parameters are investigated. Our conclusions are: A) For all realistic diode parameters, the phase modulation completely dominates the amplitude modulation. B) Performance is degraded well below the plasma frequency in the undepleted epilayer due to the presence of a second resonance, caused by the interaction of the barrier capacitance and the effective inductance due to carrier inertia, C) The effects of varying the antenna impedance, temperature, diode substrate size, and Schottky barrier height over realistic ranges are small. D) An improvement in single-sideband conversion efficiency of approximately 20 db may be obtained by increasing the epilayer doping and simultaneously reducing the diode radius. 相似文献
10.
Recent studies have shown that cobalt catalysts, used for curing of alkyd coatings, are potentially carcinogenic, and hence replacement by new environmental friendly catalysts is needed. The influence of different metal based catalysts on the oxidation process has been studied extensively in model systems, consisting of unsaturated oils. However, these results may not be representative for real coatings, since in these systems the oxygen diffusion is much lower than in model systems and therefore may have a large effect on the curing. In this paper, we will show how the curing of an alkyd coating depends on the type of catalyst (cobalt or manganese based). The curing process is studied using a high spatial resolution nuclear magnetic resonance (NMR) setup. The final network structure and cross-link density are found to be correlated with the catalyst used, i.e. a cobalt based catalyst and two manganese based catalysts. The difference in final network structure is investigated by NMR T2 relaxation analysis and the glass transition temperature Tg measured using a differential scanning calorimeter (DSC). In case of the cobalt based catalyst a cross-linking front was observed and a high cross-link density was found, compared to the manganese based catalysts, in which case no sharp cross-linking front was observed. To interpret the observed NMR profiles in more detail, simulations based on a reaction-diffusion model were performed. From the results of these simulations estimates were obtained for the reaction constants and the diffusion of oxygen for the different catalysts. 相似文献