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   207篇
  免费   9篇
  国内免费   1篇
电工技术   1篇
综合类   9篇
化学工业   47篇
金属工艺   2篇
机械仪表   1篇
建筑科学   23篇
矿业工程   1篇
能源动力   6篇
轻工业   39篇
水利工程   5篇
无线电   7篇
一般工业技术   35篇
冶金工业   16篇
自动化技术   25篇
  2024年   2篇
  2023年   2篇
  2022年   3篇
  2021年   9篇
  2020年   1篇
  2019年   3篇
  2018年   4篇
  2017年   3篇
  2016年   10篇
  2015年   5篇
  2014年   9篇
  2013年   15篇
  2012年   9篇
  2011年   18篇
  2010年   8篇
  2009年   5篇
  2008年   10篇
  2007年   14篇
  2006年   10篇
  2005年   10篇
  2004年   6篇
  2003年   9篇
  2002年   4篇
  2001年   4篇
  2000年   2篇
  1999年   4篇
  1998年   5篇
  1996年   1篇
  1995年   2篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   5篇
  1985年   2篇
  1984年   2篇
  1983年   2篇
  1982年   2篇
  1979年   1篇
  1976年   3篇
  1970年   1篇
排序方式: 共有217条查询结果,搜索用时 29 毫秒
111.
Cold atmospheric plasma (CAP) is partially ionized gas near room temperature with previously reported antitumor effects. Despite extensive research and growing interest in this technology, active components and molecular mechanisms of CAP are not fully understood to date. We used Raman spectroscopy and colorimetric assays to determine elevated nitrite and nitrate levels after treatment with a MiniFlatPlaster CAP device. Previously, we demonstrated CAP-induced acidification. Cellular effects of nitrite and strong extracellular acidification were assessed using live-cell imaging of intracellular Ca2+ levels, cell viability analysis as well as quantification of p21 and DNA damage. We further characterized these observations by analyzing established molecular effects of CAP treatment. A synergistic effect of nitrite and acidification was found, leading to strong cytotoxicity in melanoma cells. Interestingly, protein nitration and membrane damage were absent after treatment with acidified nitrite, thereby challenging their contribution to CAP-induced cytotoxicity. Further, phosphorylation of ERK1/2 was increased after treatment with both acidified nitrite and indirect CAP. This study characterizes the impact of acidified nitrite on melanoma cells and supports the importance of RNS during CAP treatment. Further, it defines and evaluates important molecular mechanisms that are involved in the cancer cell response to CAP.  相似文献   
112.
The reinforcement of cement with glass fibre textiles imbues the composite with a tensile as well as compressive load-bearing capacity. The tensile capacity allows the elimination of steel reinforcement as well as the concrete corrosion cover in structural applications. With textile reinforced concrete (TRC) thin and/or free form shells could be realized. In this paper, a parametric study is used to evaluate the structural applicability of TRC for small span (2–15 m) doubly curved roof shells. The application of two different, existing TRC material combinations demonstrates the influence of the applied composite material on the design of the shell.  相似文献   
113.
The present study worked out the effects of the additive package on both the degradation behavior and the thermal properties of a commercial polyoxymethylene (POM) homopolymer (Delrin® 900P) during an artificial thermooxidative aging. The POM pellets were investigated as received and after a storage duration of 5 weeks at 140°C in an oven. Additionally, the pellets for the initial and aged conditions were purified to remove the additives. The degradation behavior was determined by means of thermogravimetric analysis (TGA), while the thermal properties were studied with differential scanning calorimetry (DSC). Further, optical microscopy and Fourier transform infrared spectroscopy were used to follow changes occurring during the artificial aging. Dynamic TGA in nitrogen and air showed that even after a severe aging procedure, some thermooxidative stabilizer was still present. However, its effectiveness was no longer good, as the aged POM showed a lower degradation temperature than the initial material. This result is evidence that thermally sensitive and more volatile compounds were formed. Purification of the aged pellets led to a material that degraded immediately during melting. Isothermal DSC experiments carried out at several temperatures showed that the elimination of the additives increased the crystallization rate. The crystallization kinetics could be described by using the Avrami model. J. VINYL ADDIT. TECHNOL, 2008. © 2008 Society of Plastics Engineers  相似文献   
114.
Canned and jarred baby foods (74), canned and jarred adult foods (63) and 70 coffees sold in Belgium, Italy, Portugal, Spain and The Netherlands were analysed for their furan content using a validated automated headspace GC–MS procedure. Seven balsamic vinegars from Italy and Spain were also analysed. All 74 baby food samples contained detectable furan, with an average level of 37 ng/g. A total of 54 of 63 canned and jarred foods contained detectable furan with an average level of 24 ng/g. Levels of furan in coffee as consumed were very variable and reflected different preparation methods and coffee strengths. Over 50% of Italian samples contained more than 200 ng/g, whereas over 20% of Belgian coffees contained less than 21 ng/g furan. Some brews made from fine grained coffee contained much more furan than did brews made from normal or coarse grained coffee. Although furan was low in most instant coffees, two Italian products “instant espresso” and “instant mocha” contained about 150 ng/g furan. Balsamic vinegars from Spain contained 159–662 ng/g of furan; however, other samples from Spain and Italy contained only 6–25 ng/g.  相似文献   
115.
The range of antibiotic susceptibility to 13 antibiotics in 101 strains of the Lactobacillus acidophilus group was examined using the lactic acid bacteria susceptibility test medium (LSM) and broth microdilution. Additionally, microarray analysis and PCR were applied to identify resistance genes responsible for the displayed resistant phenotypes in a selection of strains. In general, narrow as well as broad unimodal and bimodal MIC distributions were observed for the Lactobacillus acidophilus group and the tested antimicrobial agents. Atypically resistant strains could be determined by visual inspection of the obtained MIC ranges for ampicillin, chloramphenicol, clindamycin, erythromycin, quinupristin/dalfopristin, streptomycin and tetracycline. For most of these atypically resistant strains underlying resistance determinants were found. To our knowledge erm(A) was detected in lactobacilli for the first time within this study. Data derived from this study can be used as a basis for reviewing present microbiological breakpoints for categorization of susceptible and resistant strains within the Lactobacillus acidophilus group to assess the safety of microorganisms intended for use in food and feed applications.  相似文献   
116.
Sports have worldwide appeal. Professional sport leagues involve significant investments in players. Events such as the Olympics Games, the Football World Cup and the major golf and tennis tournaments generate huge worldwide television audiences and many sports are multi-million dollar industries. A key aspect of sporting events is the ability to generate schedules that optimize logistic issues and that are seen as fair to all those who have an interest. This is not just restricted to generating the fixtures, but also to other areas such as assigning officials to the games in the competitions. This paper provides an annotated bibliography for sports scheduling articles. This area can be traced back over 40 years. It is noticeable that the number of papers has risen in recent years, demonstrating that scientific interest is increasing in this area.  相似文献   
117.
118.
We develop a farm- and plot-specific land-use model, which allows to examine the influence of changing socio-economic conditions on agricultural landscapes. The outstanding feature of our model is that we directly consider the knowledge of local farmers and agrarian experts for the specification of the farm-specific adaptation process. Furthermore, we visualise changes in landscape appearance by photo manipulation. The study takes place in three typical (Pre-) Alpine regions in Southern Germany and in Austria. In all study regions, we apply three scenarios: Status quo (the persistence of the current economic and agri-political conditions), liberalisation (the abolishment of public payments and decreasing of producer prices) and alternative (treating a specific development of particular importance in the respective region). The abandonment of land in marginal regions and the intensification and homogenisation of land use in more productive regions are the most important developments. The initially given farm structure is of fundamental importance for the future development of landscapes.  相似文献   
119.
The purpose of this paper is to evaluate the effects of a building parameter, namely ceiling configuration, on indoor natural ventilation. The computational fluid dynamics (CFD) code Phoenics was used with the RNG k? turbulence model to study wind motion and ventilation flow rates inside the building. All the CFD boundary conditions were described. The simulation results were first validated by wind tunnel experiment results in detail, and then used to compare rooms with various ceiling configurations in different cases. The simulation results generated matched the experimental results confirming the accuracy of the RNG k? turbulence model to successfully predict indoor wind motion for this study. Our main results reveal that ceiling configurations have certain effects on indoor airflow and ventilation flow rates although these effects are fairly minor.  相似文献   
120.
Energy conservation issues and environmental problems in recent years have increased interest in traditional architecture which is well known for its energy saving designs. This paper thoroughly investigates vernacular housing designs and evaluates on the aspect of building physics. A new research methodology which is adapted to the natural and social context of Vietnam was proposed and applied. The process was carried out step by step, including: climate zoning, systematic analysis, in-situ survey and building simulations. The results of this study indicate that vernacular housing in Vietnam is creatively adapted to the local natural conditions and uses various climate responsive strategies. Through this study, the most frequently used strategies and their effectiveness were derived. The authors also found that under extreme weather conditions, traditional designs might not be sufficient to maintain indoor thermal comfort.  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