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   1180篇
  免费   90篇
电工技术   3篇
综合类   3篇
化学工业   390篇
金属工艺   15篇
机械仪表   22篇
建筑科学   74篇
能源动力   30篇
轻工业   340篇
水利工程   24篇
石油天然气   10篇
无线电   30篇
一般工业技术   143篇
冶金工业   84篇
原子能技术   2篇
自动化技术   100篇
  2024年   2篇
  2023年   9篇
  2022年   41篇
  2021年   76篇
  2020年   38篇
  2019年   44篇
  2018年   51篇
  2017年   52篇
  2016年   54篇
  2015年   51篇
  2014年   45篇
  2013年   87篇
  2012年   78篇
  2011年   97篇
  2010年   81篇
  2009年   69篇
  2008年   46篇
  2007年   56篇
  2006年   48篇
  2005年   30篇
  2004年   29篇
  2003年   27篇
  2002年   26篇
  2001年   12篇
  2000年   8篇
  1999年   11篇
  1998年   10篇
  1997年   11篇
  1996年   10篇
  1995年   3篇
  1994年   3篇
  1993年   4篇
  1992年   5篇
  1990年   1篇
  1989年   3篇
  1987年   2篇
  1986年   3篇
  1985年   4篇
  1984年   5篇
  1983年   7篇
  1982年   5篇
  1981年   6篇
  1980年   3篇
  1979年   6篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1974年   4篇
  1973年   1篇
排序方式: 共有1270条查询结果,搜索用时 15 毫秒
131.
14 deaf 54–83 mo olds were videotaped playing once with each of 4 partners: a familiar deaf playmate, a familiar hearing playmate, an unfamiliar hearing child who was a playmate of another deaf child, and an unfamiliar hearing child who had little experience playing with deaf children. 21 hearing and 7 deaf playmates participated. Deaf Ss rarely used language, and formal language use was not related to measures of interaction or play even when playing with another deaf child. Instead, interaction and pretense seemed to be related to the deaf Ss' nonlinguistic communication abilities. Partner hearing status primarily affected communication, with communication between deaf playmates being more visual (both linguistic and nonlinguistic) and less object-based than communication between deaf and hearing playmates. Familiarity played a larger role than experience in improving interaction between deaf and hearing children. The hearing children were more responsive to and used more visual communication devices with their deaf playmate than an unfamiliar deaf child. But the hearing playmates were no better at playing with an unfamiliar deaf child than were hearing children who had little experience playing with deaf children. Implications for the understanding of young children's communication abilities and for deaf educational programs are discussed. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
132.
Study of self-stratifying compositions   总被引:2,自引:0,他引:2  
Paint applied as a single layer, and its spontaneous separation to form a primer and a top coat, is one of the newest concepts of the effective and economical application of two layers in one step. The influence of the molecular weight of epoxy oligomer and acrylic polymer and their ratio on self-stratification was investigated. The degree of stratification depending on molecular weight and their mutual ratio was determined using ATR-FTIR spectroscopy, differential scanning calorimetry, microscopy techniques, adhesion tests, and surface tension measurements. Phase separation and self-stratification of two-component homogenous mixtures were followed using FTIR technique and surface tension measurements. As a result of these investigations, optimal oligomeric/polymeric composition was selected. The obtained coating system showed good mechanical properties, gloss, and interlayer adhesion.  相似文献   
133.
134.
This paper outlines “point to point” method of allocating the marginal costs of energy transmission in power network to receiving nodes of the network, based on redistribution of line flow in the network onto shares originating from respective nodes charge allocation. Presented results of the marginal costs calculation of energy transmission were carried out in closed network.  相似文献   
135.
Associative and statistical theories of causal and predictive learning make opposite predictions for situations in which the most recent information contradicts the information provided by older trials (e.g., acquisition followed by extinction). Associative theories predict that people will rely on the most recent information to best adapt their behavior to the changing environment. Statistical theories predict that people will integrate what they have learned in the two phases. The results of this study showed one or the other effect as a function of response mode (trial by trial vs. global), type of question (contiguity, causality, or predictiveness), and postacquisition instructions. That is, participants are able to give either an integrative judgment, or a judgment that relies on recent information as a function of test demands. The authors concluded that any model must allow for flexible use of information once it has been acquired. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
136.
Cognitive-behavioral therapy (CBT) is an effective treatment of bulimia nervosa, but its mechanisms of action have not been established. In this study the authors analyzed the results of a randomized control trial comparing CBT with Interpersonal Psychotherapy (IPT) to identify possible mediators of change of CBT for BN and its time course of action. Reduction in dietary restraint as early as Week 4 mediated posttreatment improvement in both binge eating and vomiting. Measures of self-efficacy concerning eating behavior, negative affect, and body shape and weight at midtreatment were also significantly associated with posttreatment outcome at 20 wks. No evidence was found that the therapeutic alliance mediated treatment outcome. CBT had a significantly more rapid treatment effect than IPT, with 62% of posttreatment improvement evident by Week 6. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
137.
We report the first heterologous production of a fungal rutinosidase (6‐O‐α‐L ‐rhamnopyranosyl‐β‐D ‐glucopyranosidase) in Pichia pastoris. The recombinant rutinosidase was purified from the culture medium to apparent homogeneity and biochemically characterized. The enzyme reacts with rutin and cleaves the glycosidic linkage between the disaccharide rutinose and the aglycone. Furthermore, it exhibits high transglycosylation activity, transferring rutinose from rutin as a glycosyl donor onto various alcohols and phenols. The utility of the recombinant rutinosidase was demonstrated by its use for the synthesis of a broad spectrum of rutinosides of primary (saturated and unsaturated), secondary, acyclic and phenolic alcohols as well as for the preparation of free rutinose. Moreover, the α‐L ‐rhamnosidase‐catalyzed synthesis of a chromogenic substrate for a rutinosidase assay – para‐nitrophenyl β‐rutinoside – is described.

  相似文献   

138.
139.
Removal of numerous classes of pharmaceuticals from the municipal and industrial wastewater, using conventional wastewater treatment, is incomplete and several studies suggested that improvement of this situation would require the application of advanced treatment techniques. This is particularly important for the treatment of industrial effluents, released from pharmaceutical industries, which can contain rather high concentrations of antimicrobials. The aim of this work was to evaluate membrane bioreactors (MBRs), nanofiltration, reverse osmosis and ozonation, as well as their combinations, for the removal of antimicrobials from a synthetic wastewater which simulated highly contaminated industrial effluents. The study was performed using a mixture of four important classes of antimicrobials, including sulfonamides (SA), fluoroquinolones (FQ), macrolides (MAC) and trimethoprim (TMP). Performance of two different types of MBRs, Kubota and Zenon, was evaluated under different regimes regarding hydraulic retention time, total organic load and total nitrogen load. It was shown that elimination of SA in MBR treatment was very efficient, while the elimination of MAC, FQ, and TMP was incomplete. A mass balance of these contaminants in MBR suggested that microbial transformation represented the main mechanism, while only a small percentage was eliminated from the aqueous phase by adsorption onto sludge particles. Nanofiltration and reverse osmosis achieved high elimination rates however produced highly contaminated concentrate. High removal was achieved using ozonation, but further research is needed to characterize formed ozonation products.  相似文献   
140.
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