全文获取类型
收费全文 | 2679篇 |
免费 | 102篇 |
国内免费 | 5篇 |
学科分类
工业技术 | 2786篇 |
出版年
2023年 | 9篇 |
2022年 | 11篇 |
2021年 | 49篇 |
2020年 | 39篇 |
2019年 | 55篇 |
2018年 | 48篇 |
2017年 | 61篇 |
2016年 | 69篇 |
2015年 | 57篇 |
2014年 | 79篇 |
2013年 | 185篇 |
2012年 | 135篇 |
2011年 | 165篇 |
2010年 | 130篇 |
2009年 | 130篇 |
2008年 | 160篇 |
2007年 | 134篇 |
2006年 | 101篇 |
2005年 | 93篇 |
2004年 | 73篇 |
2003年 | 73篇 |
2002年 | 68篇 |
2001年 | 37篇 |
2000年 | 44篇 |
1999年 | 47篇 |
1998年 | 81篇 |
1997年 | 62篇 |
1996年 | 41篇 |
1995年 | 47篇 |
1994年 | 40篇 |
1993年 | 30篇 |
1992年 | 20篇 |
1991年 | 14篇 |
1990年 | 27篇 |
1989年 | 24篇 |
1988年 | 28篇 |
1987年 | 13篇 |
1986年 | 18篇 |
1985年 | 22篇 |
1984年 | 36篇 |
1983年 | 23篇 |
1982年 | 25篇 |
1981年 | 19篇 |
1980年 | 17篇 |
1979年 | 12篇 |
1978年 | 20篇 |
1977年 | 14篇 |
1976年 | 20篇 |
1975年 | 17篇 |
1974年 | 18篇 |
排序方式: 共有2786条查询结果,搜索用时 78 毫秒
21.
In the last rice harvest season, experimental results have been obtained on the efficiency and drying quality of a solar assisted heat pump drying prototype system. The system has been operated as a solar and heat pump system and drying curves for the different options have been obtained. The advantage of the low temperature and better control in the drier shows that the heat pump assisted solar drying system is an excellent alternative to traditional drying systems. 相似文献
22.
23.
Neil Roberts Silas Barbosa Lance D. Blumhardt Ron A. Kawoski Richard H. T. Edwards 《Magma (New York, N.Y.)》1994,2(3):375-378
Point counting represents a convenient and efficient technique for estimating the area of transects through multiple sclerosis (MS) lesions on magnetic resonance (MR) images obtained for sections through the brain. When sectioning has been performed according to the Cavalieri method, unbiased estimates of the total volume of MR-visible MS plaques can be obtained with a precision of 3–5% in 5–10 min. 相似文献
24.
As hierarchically controlled computer-integrated manufacturing systems growthey tend to become complex and their designability, maintainability, expandability and fault tolerance deteriorate. As an alternative, herterarchical control architectures offer prospects of reduced compexity, reduced software development costs, high modularity, high flexibility, and improved fault tolerance. By locating decision making where information originates, global information is reduced to a minimum, scheduling becomes dynamic, machines and parts become “intelligent” entities that cooperatively interact, and the overall system is decomposed into functionally simplified, modular parts.Three flexible machining cell control systems have been constructed at the University of Wisconsin-Madison and are described in this paper: a centralized controller, a hierarchical controller with dynamic scheduling, and a fully distributed heterarchical controller with “intelligent parts”. Comparative results are reported showing that the heterarchical approach possesses a number of advantages including increased fault-tolerance, inherent adaptability and reconfigurability, decreased complexity, and reduced software development cost. 相似文献
25.
Hartouni E.P. Jensen D.A. Klima B. Kreisler M.N. Rabin M.S.Z. Uribe J. Church M. Gara A. Gottschalk E. Hylton R. Knapp B.C. Sippach F.W. Stern B. Wiencke L. Christian D. Gutierrez G. Holmes S.D. Strait J.B. Wehmann A. Avilez C. Correa W. Rosales A. Forbush M. Huson F.R. White J. 《IEEE transactions on nuclear science》1989,36(5):1480-1484
A novel technique for both online and offline computation is presented. With this technique, a reconstruction analysis in elementary particle physics, otherwise prohibitively long, has been accomplished. It will be used online in an upcoming Fermilab experiment to reconstruct more than 100000 events per second and to trigger on the basis of that information. The technique delivers 40 gigaoperations per second, has a bandwidth on the order of gigabytes per second, and has a modest cost. An overview of the program, details of the system, and performance measurements are presented 相似文献
26.
Expert performance: Its structure and acquisition. 总被引:2,自引:0,他引:2
Counter to the common belief that expert performance reflects innate abilities and capacities, recent research in different domains of expertise has shown that expert performance is predominantly mediated by acquired complex skills and physiological adaptations. For elite performers, supervised practice starts at very young ages and is maintained at high daily levels for more than a decade. The effects of extended deliberate practice are more far-reaching than is commonly believed. Performers can acquire skills that circumvent basic limits on working memory capacity and sequential processing. Deliberate practice can also lead to anatomical changes resulting from adaptations to intense physical activity. The study of expert performance has important implications for our understanding of the structure and limits of human adaptation and optimal learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
27.
Age differences in 2 specific processing dimensions of metamemory, namely memory knowledge and memory monitoring, were examined. Young and old Ss recalled lists of words paired with letter, rhyme, and meaning cues over 2 trials. On both trials, Ss made predictions of recall likelihood on presentation of each word-cue pair. No age differences in initial predictions (i.e., prior memory knowledge) were apparent, whereas age-based performance differences were observed. On Trial 2, both young and old Ss significantly revised their predictions; however, old adults monitored only global discrepancies between previous expectation and performance. Young adults raised and lowered expectations across cue types in accordance with their previous performance. Age differences in processing speed accounted for some but not all of the memory-monitoring differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
Robin Daniel J.; Berthier Neil E.; Clifton Rachel K. 《Canadian Metallurgical Quarterly》1996,32(5):824
Infants were presented with a moving object under 2 lighting conditions to investigate the role of vision in early reaching. The motion of the target object also allowed for an analysis of the infants' ability to use a predictive style of reaching. Infants were tested twice, at 5 and 7.5 months of age, with a moving object in the light and the same object painted with luminescent paint in the dark. Infants successfully contacted the glowing object on about half of their attempts at both ages, although 7.5 month-olds reached more often. Infants also took into account the motion of the target object by aiming their reaches ahead of the object and by reaching with their contralateral hand. These results suggest that proprioceptive feedback and sight of the target allow for successful reaching with limited visual information, even in relatively complex reaching tasks. The infants' success also demonstrates their ability to adapt their movements and reaching strategy to the speed and trajectory of the target object in order to reach predictively. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
29.
Juntunen Cindy L.; Atkinson Donald R.; Reyes Carla; Gutierrez Maria 《Canadian Metallurgical Quarterly》1994,31(2):327
Investigated whether (1) feminist identity development for women therapists was related to their use of feminist therapy behaviors (FTBs) and (2) feminist identity development and use of FTBs for women therapists were related to self-identification as a feminist therapist. 153 women psychologists (aged 30–77 yrs) were administered a women's issues in therapy questionnaire, which included a short version of the Feminist Identity Scale (FIS; K. M. Rickard, 1989, 1990). Ss were categorized into stages of feminine identity development according to their scores on 4 subscales of the FIS: Passive-Acceptance (PA), Revelation (REV), Embeddedness (EMB), and Synthesis (SYN). Ss scoring high on SYN and REV, and low on PA, reported greater use of FTBs; scores on the EMB were not related to the use of FTBs. All 4 subscales were predictive of women therapists who self-identified as feminist therapists. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
30.
Allen Karen; Linn Richard T.; Gutierrez Horacio; Willer Barry S. 《Canadian Metallurgical Quarterly》1994,39(1):29
Investigated burden experienced by 60 spouses and 71 parents who served as primary caregivers to individuals with traumatic brain injury (BI). Burden levels, as assessed by the Questionnaire on Resources and Stress (QRS-SF), were compared for spouses and parents. Both parents and spouses exhibited high levels of burden. Relative to spouses, parents reported significantly greater burden related to lifespan care. Spouses reported significantly less personal reward than did parents. The presence of social aggression and cognitive disability in the individual with BI was found to have a greater association with subjective burden of caregivers than was the presence of physical disability or injury severity. Results of previous studies with QRS-SF scores show that the responsibility assumed by spouses and parents of persons with BI was as great as that experienced by families of people with severe chronic physical disabilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献