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   274篇
  免费   13篇
电工技术   2篇
综合类   1篇
化学工业   58篇
金属工艺   1篇
机械仪表   9篇
建筑科学   10篇
能源动力   8篇
轻工业   39篇
水利工程   2篇
石油天然气   1篇
无线电   9篇
一般工业技术   43篇
冶金工业   7篇
原子能技术   3篇
自动化技术   94篇
  2023年   3篇
  2022年   2篇
  2021年   26篇
  2020年   5篇
  2019年   13篇
  2018年   18篇
  2017年   14篇
  2016年   11篇
  2015年   8篇
  2014年   16篇
  2013年   37篇
  2012年   21篇
  2011年   25篇
  2010年   18篇
  2009年   10篇
  2008年   11篇
  2007年   6篇
  2006年   8篇
  2005年   4篇
  2004年   2篇
  2003年   2篇
  2002年   5篇
  2001年   3篇
  2000年   4篇
  1999年   3篇
  1998年   4篇
  1997年   2篇
  1996年   1篇
  1994年   1篇
  1991年   1篇
  1990年   1篇
  1968年   2篇
排序方式: 共有287条查询结果,搜索用时 600 毫秒
61.
Accurate and reliable data on microgram and nanogram quantities of some essential and toxic elements in most food articles are very scarce. Neutron activation analysis (NAA), with its essentially blankfree advantage, is a valuable approach in the field of determination of trace elements in different foodstuffs and diets. Accordingly, various radiochemical (RNAA) and instrumental (INAA) approaches have been developed in our laboratory for the elements As, Cd, Co, Cu, Hg, I, Mo, Ni, Sb, Se, Sn, Th, U, V, and others, and verified by the analysis of compositionally appropriate certified reference materials.This communication was presented as a poster at EURO FOOD CHEM VIII, Vienna, September 18–20, 1995, and was one of three such posters which were awarded as being outstanding  相似文献   
62.
Water Resources Management - Optimum Control by Artificial Intelligence (OCAI) is presented in this paper as a dynamic decision making algorithm for optimising pumpage schedule to remediate a...  相似文献   
63.
The adsorption of methylene blue dye (MBD) from aqueous solutions was investigated using a new composite made up of shrimp waste chitosan and zeolite as adsorbent. Response surface methodology (RSM) was used to optimize the effects of process variables, such as contact time, pH, adsorbent dose and initial MBD concentration on dye removal. The results showed that optimum conditions for removal of MBD were adsorbent dose of 2.5 g/L and pH of 9.0, and initial MBD concentration of 43.75 mg/L and contact time of 138.65 min. The initial concentration of dye had the greatest influence on MBD adsorption among other variables. The experimental data were well fitted by the pseudo-second order kinetic model, while the Freundlich isotherm model indicated a good ability for describing equilibrium data. According to this isotherm model, maximum adsorption capacity of the composite was 24.5 mg/g. Desorption studies showed that the desorption process is favored at low pH under acidic conditions.  相似文献   
64.
65.
Fishways are used to allow fish to migrate around water infrastructure, whether movements are in the upstream or downstream direction. Hydrodynamic conditions within various fishways, including turbulence levels, are important for successful fish passage. A numerical hydrodynamic study was conducted for V-weir fishways, which assist species migrating upstream. The variables investigated included, fishway slopes of 4%, 7%, and 10%, relative spacing between weirs of 1.3, 2.6, and 4 (D/L, ratio of distance between weirs to pool width), and weir angles of 22.5°, 40°, and 60°. Turbulence characteristics, including turbulent kinetic energy (TKE), Reynolds shear stress (RSS), turbulent intensity (TI), turbulent dissipation (TD), as well as maximum water velocity, were examined by CFD (computational fluid dynamics) simulation using a re-normalized group or RNG turbulence model. The CFD was calibrated with flow measurements made in a physical model of the V-weir fishway in laboratory control experiments. Based on inferences from fish passage literature, the results showed that, in the range of parameters studied, a weir angle of 22.5°, a slope of 10% and relative spacing between weirs of 1.3 and 2.6 were assessed as offering the best potential performance for several species and sizes of fish, while the latter has lower cost as it requires fewer weirs. The V-weir fishway may be adaptable for smaller fish.  相似文献   
66.
Planning and production optimization within multiple mines or several work sites (entities) mining systems by using fuzzy linear programming (LP) was studied.LP is the most commonly used operations research methods in mining engineering.After the introductory review of properties and limitations of applying LP,short reviews of the general settings of deterministic and fuzzy LP models are presented.With the purpose of comparative analysis,the application of both LP models is presented using the example of the Bauxite Basin Niksic with five mines.After the assessment,LP is an efficient mathematical modeling tool in production planning and solving many other single-criteria optimization problems of mining engineering.After the comparison of advantages and deficiencies of both deterministic and fuzzy LP models,the conclusion presents benefits of the fuzzy LP model but is also stating that seeking the optimal plan of production means to accomplish the overall analysis that will encompass the LP model approaches.  相似文献   
67.
Software agents in e-commerce systems are assigned to the participants. Buyer and supplier agents into multi-agent system architecture of the e-commerce system negotiate with others through an automated negotiation mechanism. In this study, an automated negotiation to interact between buyer and supplier and attain agreement for both is presented. A fuzzy inference system was used to automate negotiation process and consider two effective factors in the negotiation process: requirements and preferences. Requirements are qualitative or quantitative values which the participants assign to the issues of negotiation. Preferences of the participants are priorities assigned by them to issues. These values express an importance measure of issues from a participant perspective. Proposed model applies different fuzzy inference system (FIS) schemes for qualitative and quantitative negotiation issues to enhance the satisfaction level of the buyer and supplier. The FISs infer based on the preferences and requirements of both parties. Additionally, analytic hierarchy process was used to get preferences of the issues. In this proposal, mediator uses issue trade-offs strategy in which multiple issues are traded-offs against one another. The model applies a fuzzy system approach to make trade-offs.  相似文献   
68.
69.
70.
Polyaniline composite and nanocomposite were generated in aqueous and aqueous/nonaqueous media by using ammonium peroxydisulfate as an oxidant in the presence of various surfactants such as sodium dodecylbenzenesulfonate, poly(vinyl alcohol), hydroxypropylcellulose, poly(ethylene glycol), and poly(vinyl pyrrolidone). The results indicated that the morphology and size of the particles were dependent on the type of surfactant and solution used. The size range of the particles and nanoparticles was about 75–160 nm. The molecular structure was studied by using Fourier‐transform infrared spectroscopy,and the results showed that the intensities of the peaks were dependent on the nature of the surfactant. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers  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