全文获取类型
收费全文 | 622篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 65篇 |
金属工艺 | 11篇 |
机械仪表 | 14篇 |
建筑科学 | 13篇 |
矿业工程 | 2篇 |
能源动力 | 10篇 |
轻工业 | 36篇 |
水利工程 | 3篇 |
无线电 | 51篇 |
一般工业技术 | 93篇 |
冶金工业 | 241篇 |
原子能技术 | 6篇 |
自动化技术 | 77篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 16篇 |
2012年 | 16篇 |
2011年 | 19篇 |
2010年 | 9篇 |
2009年 | 13篇 |
2008年 | 19篇 |
2007年 | 14篇 |
2006年 | 24篇 |
2005年 | 14篇 |
2004年 | 20篇 |
2003年 | 15篇 |
2002年 | 11篇 |
2001年 | 18篇 |
2000年 | 8篇 |
1999年 | 17篇 |
1998年 | 73篇 |
1997年 | 41篇 |
1996年 | 39篇 |
1995年 | 19篇 |
1994年 | 24篇 |
1993年 | 12篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 19篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 4篇 |
1972年 | 3篇 |
排序方式: 共有630条查询结果,搜索用时 26 毫秒
41.
Inthuorn Sasanakul Wipawi Vanadit-Ellis Michael Sharp Tarek Abdoun Javier Ubilla Scott Steedman Kevin Stone 《Canadian Metallurgical Quarterly》2008,134(5):657-667
Centrifuge modeling of the 17th Street Canal and Orleans Canal North levees was performed in this study. During hurricane Katrina the levees on the 17th Street Canal failed, leading to breaches in the outfall canal in the city. Two mechanisms were observed in the centrifuge modeling that could cause a breach. First, a water-filled crack formed in front of the floodwall as the water in the canal rose above the top of the levee. The levees on the 17th Street Canal, which were supported on clay foundations, failed when this cracking led to a translational (sliding) failure in the clay layer commencing at the toe of the floodwall. The levees at Orleans Canal North, where failure did not occur, were also modeled to demonstrate that the model tests could successfully simulate failure and nonfailure conditions. The centrifuge model tests identified the importance of the crack formation in relation to the stability of the floodwall. These tests also confirmed that levee geometry, floodwall depth of penetration, and the underlying soil profile were all critical to the performance of the system under flood loading. 相似文献
42.
The Secure Web Applications Project (SWAP) is an interdisciplinary research initiative between the Laboratory for Communications Engineering and the Computer Laboratory of the University of Cambridge that seeks to address the problem of application-level Web security at a higher level. The project reduces application development time and protects against a large class of application-level attacks more effectively than existing Web development methodologies. 相似文献
43.
S Engelender AH Sharp V Colomer MK Tokito A Lanahan P Worley EL Holzbaur CA Ross 《Canadian Metallurgical Quarterly》1997,6(13):2205-2212
Huntington's disease (HD) is an inherited neurodegenerative disease caused by expansion of a polyglutamine repeat in the HD protein huntingtin. Huntingtin's localization within the cell includes an association with cytoskeletal elements and vesicles. We previously identified a protein (HAP1) which binds to huntingtin in a glutamine repeat length-dependent manner. We now report that HAP1 interacts with cytoskeletal proteins, namely the p150 Glued subunit of dynactin and the pericentriolar protein PCM-1. Structural predictions indicate that both HAP1 and the interacting proteins have a high probability of forming coiled coils. We examined the interaction of HAP1 with p150 Glued . Binding of HAP1 to p150 Glued (amino acids 879-1150) was confirmed in vitro by binding of p150 Glued to a HAP1-GST fusion protein immobilized on glutathione-Sepharose beads. Also, HAP1 co-immunoprecipitated with p150 Glued from brain extracts, indicating that the interaction occurs in vivo . Like HAP1, p150 Glued is highly expressed in neurons in brain and both proteins are enriched in a nerve terminal vesicle-rich fraction. Double label immunofluorescence experiments in NGF-treated PC12 cells using confocal microscopy revealed that HAP1 and p150 Glued partially co-localize. These results suggest that HAP1 might function as an adaptor protein using coiled coils to mediate interactions among cytoskeletal, vesicular and motor proteins. Thus, HAP1 and huntingtin may play a role in vesicle trafficking within the cell and disruption of this function could contribute to the neuronal dysfunction and death seen in HD. 相似文献
44.
It has been well documented that ascorbate enhances iron uptake, with a proposed mechanism based on reduction to the more absorbable ferrous form. We have performed a study on the effects of ascorbate on ferric iron uptake in the human epithelial Caco-2 cell-line. Ascorbate increased uptake in a concentration-dependent manner with a significant difference between iron uptake and reduction. Uptake kinetics are characteristic of a non-essential activator and the formation of an Fe3+–ascorbate complex. This investigation provides evidence that ascorbate enhances the apical uptake of ferric iron into Caco-2 cells through the formation of a Fe3+–ascorbate complex. 相似文献
45.
Pennebaker James W.; Colder Michelle; Sharp Lisa K. 《Canadian Metallurgical Quarterly》1990,58(3):528
On the basis of previous work, freshmen should evidence improved health after writing about their thoughts and feelings associated with entering college. One hundred thirty subjects were assigned to write either about coming to college or about superficial topics for 20 min on 3 days. One fourth of the subjects in each group wrote during the 1st, 5th, 9th, or 14th week of classes. Physician visits for illness in the months after writing were lower for the experimental than for the control subjects. Self-reports of homesickness and anxiety were higher in the experimental group 2–3 months after writing. By year's end, experimental subjects were either superior or similar to control subjects in grade average and in positive moods. No effects emerged as a function of when people wrote, suggesting that the coping process can be accelerated. Implications for comparing insight treatments with catharsis and for distinguishing between objective and self-report indicators of distress are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
46.
Measurements of strain release1 showed that check results were obtained only when the previous history of the samples was the same. Moreover, it was found that the release of strain was more rapid at first than could be accounted for by the equation of Adams and Williamson. This paper discusscs the effect of previous history on the measurements, describes an improved device for loading the specimens, and suggests a logarithmic equation which, in general, fits the observations better than that of Adams and Williamson. Tests of the equation are made both on data obtained from the modified apparatus described and on the data of Adams and Williamson. It is indicated that the Adams and Williamson equation gives too long an annealing time at higher temperatures and too short an annealing time at lower temperatures. It appears that the rate of release of strain depends on some power of the strain which varies from unity at high temperatures where the glass is a viscous fluid to a higher power at low temperatures where the release of strain is elastico-viscous in character. With a siugle specimen at any fixed temperature in the annealing range, however, it appears that the release of strain in various parts of the specimen takes place at a rate which is proportional to the strain, but that the rate undergoes continual change with time. 相似文献
47.
Evaluation of the degree of cure of a coating 总被引:1,自引:0,他引:1
Coating cure is compared using pencil hardness, MEK rubs, and thumb twist test to evaporation rate analysis (ERA). ERA is
rated most objective and reproducible.
Department of Polymer Science, Hattiesburg, MS.
Rockville, MD. 相似文献
48.
Rula A. Deeb Jonathan O. Sharp Andrew Stocking Shane McDonald Kimberlee A. West Maryline Laugier Pedro J. J. Alvarez Michael C. Kavanaugh Lisa Alvarez-Cohen 《Canadian Metallurgical Quarterly》2002,128(9):868-875
Recent legislation in several states has called for the removal of methyl tert-butyl ether (MTBE) from gasoline. In order to comply with Federal Clean Air Act requirements for carbon monoxide and ozone attainment, ethanol is being considered as a replacement for MTBE. The objective of this study is to evaluate the potential impact of ethanol on benzene plume lengths in subsurface environments following accidental spills of ethanol-blended gasoline. Two types of studies were conducted here. First, laboratory studies were performed using a pure culture indigenous to a gasoline-contaminated aquifer to evaluate the effect of ethanol on the rate of benzene biodegradation under aerobic conditions. Results from microbial studies showed that the biodegradation of 25 mg/L benzene was severely inhibited in the presence of 25 mg/L ethanol. While the enzymes responsible for benzene biodegradation by the culture were inducible, ethanol degradation appeared to be constitutive. Second, a two-dimensional model was developed to quantify the impact of ethanol on benzene plume lengths using weighted-average aerobic and anaerobic biodegradation rates for benzene in the presence and absence of ethanol. Model simulations indicated that benzene plume lengths are likely to increase by 16–34% in the presence of ethanol. 相似文献
49.
50.
Teri Smith Susan Sharp Ann M. Manzardo Merlin G. Butler 《International journal of molecular sciences》2015,16(3):4416-4428
Advances made in genetic testing and tools applied to pharmacogenetics are increasingly being used to inform clinicians in fields such as oncology, hematology, diabetes (endocrinology), cardiology and expanding into psychiatry by examining the influences of genetics on drug efficacy and metabolism. We present a clinical case example of an adolescent male with anxiety, attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder who did not tolerate numerous medications and dosages over several years in attempts to manage his symptoms. Pharmacogenetics testing was performed and DNA results on this individual elucidated the potential pitfalls in medication use because of specific pharmacodynamic and pharmacokinetic differences specifically involving polymorphisms of genes in the cytochrome p450 enzyme system. Future studies and reports are needed to further illustrate and determine the type of individualized medicine approach required to treat individuals based on their specific gene patterns. Growing evidence supports this biological approach for standard of care in psychiatry. 相似文献