首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   102篇
  免费   1篇
  国内免费   3篇
化学工业   6篇
金属工艺   3篇
机械仪表   4篇
建筑科学   4篇
能源动力   1篇
轻工业   65篇
无线电   2篇
一般工业技术   11篇
冶金工业   6篇
自动化技术   4篇
  2015年   1篇
  2014年   1篇
  2013年   10篇
  2012年   2篇
  2011年   1篇
  2010年   1篇
  2009年   2篇
  2008年   2篇
  2007年   1篇
  2006年   1篇
  2004年   1篇
  2003年   4篇
  2000年   1篇
  1999年   3篇
  1998年   2篇
  1997年   4篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1992年   4篇
  1991年   2篇
  1990年   3篇
  1989年   1篇
  1988年   3篇
  1987年   4篇
  1986年   4篇
  1985年   7篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
  1978年   3篇
  1977年   2篇
  1976年   3篇
  1974年   2篇
  1973年   3篇
  1972年   1篇
  1971年   2篇
  1970年   1篇
  1969年   2篇
  1968年   3篇
  1967年   3篇
  1966年   2篇
  1960年   1篇
  1958年   1篇
  1955年   1篇
排序方式: 共有106条查询结果,搜索用时 15 毫秒
1.
Attachment of Pseudomonas fragi ATCC 4973 to a sterile stainless steel surface was followed under stationary and dynamic growth conditions at 25°C and 4°C using scanning electron microscopy techniques. The organism was grown in 10% reconstituted nonfat dry milk for 28 hr at 25°C and 9 days at 4°C. Attachment was ob served in both the stationary and dynamic environments at 1/2 hr at 25°C and at 2 hr at 4°C. There appeared to be no difference in the development of attachment fibrils on the organisms in the two environments or at the two temperatures. The extent of attachment increased as the microbial population increased over the growth cycle under both environments at both temperatures.  相似文献   
2.
This report describes an evolution of research methodology for adducing evidence regarding whether the self functions as a control system. While there has been a great number of studies in the literature on personality and social psychology aimed at demonstrating that behavior of many kinds can be affected by focusing attention upon the subject's self-concept, or by challenging or threatening it, little attention has been given to the question of why this would be so. A proposed explanation would be that the self functions as a control system. Testing this hypothesis has entailed development of a methodological approach in which control action occurs predictably rather than having a statistical probability. This has required defining a model and testing it by predictions rather than attempting to isolate underlying variables with multivariate techniques.  相似文献   
3.
The preference for fistulae as the hemodialysis access of choice has led to a significant number of accesses that are less than ideal for cannulation. Buttonhole cannulation is ideal for such accesses, but the technique for creation provides major challenges. In 12 patients, buttonhole tunnel tracks were created by leaving the polyurethane catheter of a Clampcath® hemodialysis needle indwelling for 10 days after the initial cannulation. After each dialysis the catheter was flushed, and dressed with an antibacterial ointment and gauze. Dialysis was carried out via the catheter during that time. After day 10, the catheter was removed, the tunnel track covered with an antibacterial dressing and the tunnel track was cannulated with a dull buttonhole needle at the next dialysis. Successful buttonhole accesses were created in 11 patients after 10 days, the 12th patient required a single sharp needle cannulation before using dull needles. During the first 2 weeks of dull needle cannulation both pain experienced on cannulation and the difficulty cannulating the access were significantly less than in the classical buttonhole technique (P<0.01). Complications during the follow-up period (6 months–1.5 years) included difficulty cannulating with a dull needle (22) and antibacterial agent induced contact dermatitis (4). There was no episode of sepsis or tunnel track infection. Initial cannulation of the fistula using a Clampcath® hemodialysis needle, leaving the polyurethane catheter indwelling for 10 days, is a simple, safe, and effective technique for the creation of buttonhole tunnel tracks.  相似文献   
4.
A 5-layer passive organic dermal sampler was developed to allow the collection, retention, and recovery of a variety of organic compound classes simultaneously. The 5-layers, from outside in, consisted of polypropylene, polyurethane foam, C-18 solid-phase extraction disk, ethylene tetrafluoroethylene, and activated carbon cloth. The layers were enclosed in aluminum foil and placed in a muslin envelope that had a 40.0 mm diameter opening.

Ten samplers were spiked separately with three levels of diesel oil, a 50/50 diesel oil/asphalt mixture, and asphalt binder. For the diesel oil spikes, recoveries were 69.9, 71.3, 88.8, and 95.4% for 10, 10, 50, and 100 mg of diesel oil. For the 50/50 mixture, recoveries were 105.4, 92.8, and 92.0% for 10, 50, and 100 mg of the 50/50 mixture. For the asphalt binder spikes, recoveries were 104.7, 100.2, and 100.1% for 10, 50, and 100 mg of asphalt binder. For repeatability assessment, 7 samplers were spiked with 50 mg of the 50/50 mixture and recoveries averaged 92.6% (standard deviation 8.6). Samplers tested on asphalt paving workers proved functional, comfortable, flexible, and durable.  相似文献   
5.
We consider a single-pass free-electron laser (FEL) amplifier, driven by an rf-linac followed by a damping ring for reduced emittance, for use in generating coherent light in the soft x-ray region. The dependence of the optical gain on electron-beam quality, studied with the three-dimensional FEL simulation code FELEX, is given and related to the expected power of self-amplified spontaneous emission. We discuss issues for the damping ring designed to achieve the required electron-beam quality. The idea of a multipass regenerative amplifier is also presented.  相似文献   
6.
This paper is devoted to the modelling and analysis of the problem of the safety and residual lifetime of pressurized components (e.g. pressure vessels, apparatus, pipelines) with zones of local corrosion damage. Corrosion damage is the most common form of structural material degradation in service conditions, in particular, in the chemical and gas, and oil industries. Attention is paid to nonstationary regimes of the component operation, e.g., start‐stop regimes. It is shown that the critical parameters calculated taking into account the nonstationary loading can be lower compared with ones determined for the stationary regimes, e.g., on the basis of the ASME Code B31G.  相似文献   
7.
8.
DETECTION OF THE VIABLE BUT NONCULTURABLE STATE IN ESCHERICHIA COLI O157:H7   总被引:2,自引:0,他引:2  
Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is recognized as a frequent cause of gastroenteritis ranging from mild to severe bloody diarrhea. The Shiga-like toxin produced by EHEC can result in hemolytic uremic syndrome, now the major cause of acute kidney failure in children in the United States. Inadequately cooked beef is most commonly implicated in the transmission of EHEC, although only a small fraction of cattle appear to harbor the organism. In several studies EHEC positive herds were detected only in the summer months correlating with the occurrence of human infections. Numerous E. coli strains have been shown to enter a viable but nonculturable (VBNC) state as a result of environmental stresses, including low temperature. Using traditional plating methods and the BacLight Molecular Probe, we monitored EHEC strains incubated in river water (RW) and artificial sea water (ASW) at temperatures of 5C and 25C for their entry into the VBNC state. EHEC strains remained culturable for over 40 days in both ASW and RW incubated at 25C. In ASW, these levels were higher than a non-EHEC control. At 5C, the number of culturable EHEC cells dropped gradually in both RW and ASW. Using the BacLight Molecular Probe, we were able to demonstrate that these cells, though not culturable, were viable indicating entry into the VBNC state. Our study suggests that temperature and not salinity is the primary signal for entry into this state .  相似文献   
9.
A study of the vaporization of La2O3, Nd2O3, and Y2O3 at high temperatures has been carried out by the Knudsen effusion technique. The methods employed, the results of the measurements, and the low-temperature heat capacities of these materials, which were determined for the purpose of calculating thermal functions of the oxides, are discussed. All the foregoing oxides react with tantalum, forming gaseous tantalummonoxide as a principal product. Cubic tantalates of lanthanum and neodymium are also formed in these reactions.  相似文献   
10.
62 ALCOHOLIC PATIENTS WERE ADMINISTERED THE WITKIN ROD AND FRAME TEST BEFORE AND AFTER 8-10 WK. OF PSYCHIATRIC TREATMENT. THERE WAS SIGNIFICANTLY GREATER FIELD-INDEPENDENT PERFORMANCE FOLLOWING TREATMENT. THESE RESULTS TEND TO CAST DOUBT ON THE HYPOTHESIS THAT PERFORMANCE ON THE ROD AND FRAME TEST IS STABLE AND UNAFFECTED BY CHANGES IN BODY STATE. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号