全文获取类型
收费全文 | 340篇 |
免费 | 4篇 |
专业分类
电工技术 | 2篇 |
综合类 | 2篇 |
化学工业 | 63篇 |
金属工艺 | 9篇 |
机械仪表 | 5篇 |
建筑科学 | 15篇 |
能源动力 | 5篇 |
轻工业 | 34篇 |
无线电 | 7篇 |
一般工业技术 | 40篇 |
冶金工业 | 122篇 |
原子能技术 | 6篇 |
自动化技术 | 34篇 |
出版年
2022年 | 5篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2011年 | 11篇 |
2010年 | 13篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 8篇 |
2006年 | 15篇 |
2005年 | 9篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 22篇 |
1997年 | 20篇 |
1996年 | 9篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 13篇 |
1992年 | 6篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1976年 | 12篇 |
1974年 | 3篇 |
1969年 | 2篇 |
1966年 | 3篇 |
1957年 | 4篇 |
1952年 | 3篇 |
1951年 | 2篇 |
1948年 | 2篇 |
1905年 | 2篇 |
1901年 | 2篇 |
排序方式: 共有344条查询结果,搜索用时 265 毫秒
61.
The sequential ethylene-bridged catechol/aminophenol derivates 2-H3 and 3–H3 are potential ligands for metal-directed self-assembly processes. They are prepared via Wittig-reaction followed by a high yield reduction step with up to three simultaneous transformations. 相似文献
62.
63.
Witt Jessica K.; Proffitt Dennis R.; Epstein William 《Canadian Metallurgical Quarterly》2010,36(5):1153
This research was designed to test the predictions of 2 approaches to perception. By most traditional accounts, people are thought to derive general-purpose spatial perceptions that are scaled in arbitrary, unspecified units. In contrast, action-specific approaches propose that the angular information inherent in optic flow and ocular–motor adjustments is rescaled and transformed into units related to intended actions. A number of studies have shown, for example, that the apparent distance to targets is scaled by the effort required to walk the extent. Such studies can be accommodated by the traditional account by asserting that the experimental manipulations of walking effort influenced not perception itself, but rather postperceptual response processes. The current studies were designed to assess when and how action-specific influences on distance perception have their effects. The results supported the action-specific account. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
64.
Hallmark SL Veneziano DA Falb S Pawlovich M Witt D 《Accident; analysis and prevention》2008,40(4):1401-1405
The effectiveness of Iowa's graduated driver's licensing (GDL) program was evaluated for a 4-year period before and after implementation in 1999. Since some changes had occurred in the crash reporting format, changes in crash rates for younger drivers were compared to those for 35-44-year-old drivers (middle-age group of drivers) who were used as a control group. After implementation of GDL, the 14-, 16- and 17-year-old age groups experienced a greater decrease in crash rate than the middle-age control group while 15-year-old experienced a smaller decrease. This suggests that the crash rate for 15-year-old drivers may actually have increased when downward trends were adjusted for. Iowa's GDL program allows holders of the instruction permit to travel unaccompanied to and from school and school-endorsed activities after obtaining a minor school license. Fifteen-year-old with minor school licenses account for up to 26.7% of 15-year-old license holders yet represent up to 74.8% of 15-year-old drivers involved in crashes (depending on the year) from 1998 to 2004. As a result, 15-year-old drivers with minor school licenses are involved in 7.2-8.9 times more crashes, are 7.7 times more likely to have one or more sanctions, and are 4.8 times more likely to receive one or more moving convictions than their peers with a regular instruction permit. This help may explain why 15-year-old drivers did not seem to benefit from implementation of the GDL program in Iowa. 相似文献
65.
Cloud studies were carried out with a polarimetric bistatic lidar setup at the Arctic Lidar Observatory for Middle Atmosphere Research in Andenes (69 degrees N, 16 degrees E), Norway. Measurements were performed at altitudes between 1.5 and 10.5 km, corresponding to scattering angles between 130 degrees and 170 degrees. The geometry, not restricted to the parallel or perpendicular laser polarization directions, gave a well-defined scattering angle, which together with polarization characterization, was used to investigate the scattering particles. The principles of the technique and the first results are presented together with an evaluation of the capabilities. 相似文献
66.
Targets presented just beyond arm's reach look closer when observers intend to touch them with a reach-extending tool rather than without the tool. This finding is one of several that suggest that a person's ability to act influences perceived distance to objects. However, some critics have argued that apparent action effects were actually due to effects on the judgments rather than on the perception. In other words, the target does not actually look closer, but participants report that it is. To help counter this argument, the current experiments used an indirect measure of perceived distance: Participants reported perceived shape or perceived parallelism. The results revealed that triangles looked shorter and lines looked more horizontal to participants who reached with a tool, and therefore could reach the targets, than they did to participants who reached without the tool. These results demonstrate convergence across multiple types of judgments, a finding that undermines alternative, judgment-based accounts and suggests that the ability to reach an object changes the perceived distance to the object. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
67.
Ehrhart Karen Holcombe; Witt L. A.; Schneider Benjamin; Perry Sara Jansen 《Canadian Metallurgical Quarterly》2011,96(2):423
We lend theoretical insight to the service climate literature by exploring the joint effects of branch service climate and the internal service provided to the branch (the service received from corporate units to support external service delivery) on customer-rated service quality. We hypothesized that service climate is related to service quality most strongly when the internal service quality received is high, providing front-line employees with the capability to deliver what the service climate motivates them to do. We studied 619 employees and 1,973 customers in 36 retail branches of a bank. We aggregated employee perceptions of the internal service quality received from corporate units and the local service climate and external customer perceptions of service quality to the branch level of analysis. Findings were consistent with the hypothesis that high-quality internal service is necessary for branch service climate to yield superior external customer service quality. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
68.
The complexity of the mass-customised forms of Gehry Partners' new art museum in Paris, the Fondation Louis Vuitton pour la création, has taken high-definition simulation techniques and embedded intelligence to a new level. Tobias Nolte and Andrew Witt of Gehry Technologies describe how the realisation of the Fondation required the development of a 3D concurrent design system that could synchronise hundreds of participants. This self-optimisation system has enabled both ‘intricate collaboration and unprecedented engineering’. The benefits have been far reaching, ranging from the detailing of tolerances to material constraints. 相似文献
69.
Patrick H. Au‐Yeung Sol M. Resnick Paul M. Witt Timothy C. Frank Felipe A. Donate Lanny A. Robbins 《American Institute of Chemical Engineers》2013,59(7):2603-2620
A novel horizontal reactive distillation apparatus and a new overall process scheme are proposed for continuous multicomponent chiral resolution via reversible enantioselective acylation of a chiral (racemic) substrate by a chiral (racemic) acyl donor. The process enables simultaneous production of up to four enantiomers with enhanced chiral purity. Kinetic studies, miniplant experiments, and process simulation results are described for a model lipase‐catalyzed reaction: (R)‐enantioselective transesterification of (R,S)‐1‐n‐butoxy‐2‐propanol with (R,S)‐1‐methoxy‐2‐acetoxypropane to produce (R)‐1‐n‐butoxy‐2‐acetoxypropane, (R)‐1‐methoxy‐2‐propanol, and the two unreacted (S)‐enantiomers of the (R,S)‐reagents. A horizontal, compartmentalized reactive distillation vessel is specified instead of a conventional reactive distillation column to provide longer liquid‐phase residence time needed for adequate conversion. Low vapor‐traffic pressure drop allows operation under vacuum at reduced temperatures for good enzyme stability and enantioselectivity. The general technology has potential as a means to producing a wide range of chiral synthons used in asymmetric syntheses of chiral pharmaceuticals and other biologically active products. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2603–2620, 2013 相似文献
70.
R. Keylwerth W. Bavendamm F. Schulz H. Kübler E. Reichenstein R. Runkel H. Schmidt K. Lünzmann H. Mayer-Wegelin W. Kast H. Witt E. Buchholz F. Kollmann H. Stockmann E. Plath K. Rügge H. Brüning H. Seitz 《Holz als Roh- und Werkstoff》1952,10(10):400-411
Ohne Zusammenfassung 相似文献