全文获取类型
收费全文 | 1468篇 |
免费 | 22篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 91篇 |
金属工艺 | 4篇 |
机械仪表 | 11篇 |
建筑科学 | 4篇 |
能源动力 | 10篇 |
轻工业 | 108篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 45篇 |
一般工业技术 | 108篇 |
冶金工业 | 1040篇 |
原子能技术 | 7篇 |
自动化技术 | 56篇 |
出版年
2023年 | 6篇 |
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 13篇 |
2018年 | 17篇 |
2017年 | 12篇 |
2016年 | 17篇 |
2015年 | 12篇 |
2014年 | 24篇 |
2013年 | 24篇 |
2012年 | 25篇 |
2011年 | 28篇 |
2010年 | 25篇 |
2009年 | 32篇 |
2008年 | 26篇 |
2007年 | 28篇 |
2006年 | 17篇 |
2005年 | 7篇 |
2004年 | 16篇 |
2003年 | 21篇 |
2002年 | 19篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 41篇 |
1998年 | 327篇 |
1997年 | 202篇 |
1996年 | 133篇 |
1995年 | 68篇 |
1994年 | 48篇 |
1993年 | 74篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 17篇 |
1989年 | 16篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1978年 | 1篇 |
1977年 | 20篇 |
1976年 | 46篇 |
排序方式: 共有1490条查询结果,搜索用时 15 毫秒
101.
Redesigning an assembly line through lean manufacturing tools 总被引:1,自引:1,他引:0
Roberto Álvarez Roque Calvo Marta M. Peña Rosario Domingo 《The International Journal of Advanced Manufacturing Technology》2009,43(9-10):949-958
The implementation of a lean manufacturing strategy represents a robust contribution to the phase sequence that leads to operational excellence and the continuous improvement through the elimination of nonvalue-added activities. Therefore, lean practices contribute substantially to plant operational performance. This paper studies the use of value stream mapping (VSM) as a tool in lean manufacturing implementation and a framework of improvement activities, in particular for an efficient introduction of kanban and milkrun techniques. A case study illustrates VSM use, as well as kanban and milkrun systems application on an assembly line. Finally, the results obtained show the path of improvement, measured through the lean rate (LR) and dock-to-dock time (DtD). 相似文献
102.
As a consequence of inadequate working methods, excessive losses of lead can occur in the slags of lead blast furnaces. The
settling of metallic lead from a slag containing 20.5 pct SiO2, 33.4 pct FeO, 16.8 pct CaO, 12.4 pct ZnO, 0.9 pct S, and 6.1 pct Pb has been studied as a function of the temperature (1200
to 1300 °C), composition (addition of CaO, ZnO, and Fe), and time (up to 2 hours). Under these conditions sufficient, although
not total, sedimentation of the metal retained is achieved. The best conditions were obtained at 1260 °C with no modification
to the composition of the slag. The settled lead was visible macroscopically in a section of the lower part of the melts. 相似文献
103.
Celia Conesa María Carmen Rota María-Dolores Pérez Miguel Calvo Lourdes Sánchez 《European Food Research and Technology》2008,228(2):205-211
The antibacterial activity of human lactoferrin from milk (hLF), recombinant human lactoferrin from Aspergillus awamori (rhLF) and their hydrolysates obtained with pepsin was investigated against Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes. The minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) were determined for all the
bacteria and the proteins assayed. Taking into account the MICs found for both lactoferrins studied, we can say that they
behave very similarly, except for L. monocytogenes for which rhLF was more active. We studied the effect that heat treatments exerted on the antibacterial activity of the two
types of lactoferrin and the only heat treatment that had a negative effect on that activity was 85 °C for 10 min. The activity
of hLF and rhLF in UHT milk and whey against E. coli O157:H7 and L. monocytogenes, was also assayed. Our results showed a reduction in the number of viable cells for both microorganisms when were incubated
with rhLF or hLF, but this decrease was lower than in broth media. 相似文献
104.
F. A. Calvo A. Ureña J. Ma. Gomez de Salazar F. Molleda A. J. Criado 《Journal of Materials Science》1988,23(4):1231-1236
Solid-state bonding between dissimilar metals, produced at elevated temperatures with the application of a bonding pressure, causes structural changes in the microstructure of the zones nearest to the bond interface. These metallurgical transformations, produced by interdiffusion in the vicinity of the bond, decide the final properties of the joint. In the present paper, such diffusional transformations have been investigated for diffusion-bonded joints of Armco iron and copper with different oxygen contents (ETPC and OFLPC). The formation of iron oxide (wustite) has been observed in the ETPC-Armco iron joints. This oxide did not appear in OFLPC-Armco iron diffusion-bonded joints. This suggests that iron oxide forms by reaction of iron with oxygen dissolved in the ETPC base metal. The formation of copper particles in the iron base matrix, near the bond interface, has been observed. This may be due to two different processes: the solid-state precipitation of copper into iron and the eutectoid reaction (γ →ε +α) at bonding temperatures above 900° C. 相似文献
105.
106.
E García R Calvo JM Rodríguez-Sasiaín R Jiménez IF Trocóniz E Suárez 《Canadian Metallurgical Quarterly》1995,39(8):1019-1023
The influence of altered protein binding on the neuromuscular effect of atracurium has been studied in rats with experimental inflammation induced by subcutaneous injection of turpentine oil. Doses of atracurium ranging from 0.45 to 1.5 mg.kg-1 were administered to control (n = 30) and to experimental inflammation induced rats (n = 30). Neuromuscular transmission was monitored by recording the twitch tension of the tibialis-anterior muscle elicited by stimulation of the sciatic nerve. Three effect parameters were recorded: (i) intensity of the effect, measured as percentage depression of baseline twitch tension, (ii) duration of drug action (min) and (iii) recovery time (min). The dose-intensity of the effect relationship was modelled using a sigmoid Emax model. The ED50 (effective dose eliciting 50% of the maximum effect) was significantly increased (P < 0.01) in the inflammation group as compared to the control group (0.94 vs. 0.68 mg.kg-1). This change was reflected in a shift of the dose-response curve to the right in the pretreated rats. For equipotent doses ED95 (defined as the effective dose eliciting 95% of maximum effect), no differences were found in recovery time and duration of action between the two groups of rats. Mucoproteins levels (index of alpha 1-acid glycoprotein (AAG) and protein binding were significantly increased in rats with experimental inflammation as compared to control rats. Based on these results, altered serum protein binding of atracurium appears to be responsible, at least in part, for the resistance to atracurium. 相似文献
107.
108.
New-generation glass-ionomer cements contain resin to improve their restorative properties. These resin-modified glass-ionomer cements vary considerably in their chemistry, which could result in corresponding variability in their physical and biological properties. This study investigated the cytotoxicity and the fluoride release of two resin-modified glass ionomers, a conventional glass-ionomer cement, and a resin composite. Samples were prepared and extracted in distilled water for 1, 4, and 7 days; eluates were filtered and tested by means of 3T3 mouse fibroblasts. Cytotoxicity (MTT assay) values were low for all materials and extraction times, indicating minimal cytotoxicity of all materials (less than 30% inhibition). Cytotoxicity of one resin-modified glass ionomer was significantly higher than for the other materials (p < 0.001). One resin-modified glass ionomer and the conventional glass-ionomer cement released significantly more fluoride at each time interval (p < 0.001) than the other resin-modified glass-ionomer cement and the resin composite. Fluoride release and cytotoxicity were correlated (r2 = 0.60; p < 0.001), although the fluoride release does not account for the cytotoxicity observed. Cytotoxicity and fluoride release suggest that one hybrid behaved more like a conventional glass ionomer, and the other like a resin composite. These differences may have implications for material selection in specific clinical situations. 相似文献
109.
An axiomatization of criteria importances appearing in a given aggregation operator is proposed. Some distinguished examples are recalled. For the class of k-medians, an integral based approach for inclusion of criteria importances is introduced. Several examples are given. The case of ordinal scales is also discussed 相似文献
110.