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   302篇
  免费   6篇
电工技术   1篇
化学工业   32篇
金属工艺   2篇
机械仪表   3篇
建筑科学   15篇
矿业工程   2篇
能源动力   1篇
轻工业   67篇
水利工程   4篇
无线电   15篇
一般工业技术   39篇
冶金工业   75篇
原子能技术   1篇
自动化技术   51篇
  2023年   1篇
  2022年   2篇
  2021年   6篇
  2020年   1篇
  2019年   4篇
  2018年   1篇
  2017年   3篇
  2016年   4篇
  2015年   8篇
  2014年   8篇
  2013年   20篇
  2012年   8篇
  2011年   12篇
  2010年   14篇
  2009年   9篇
  2008年   17篇
  2007年   17篇
  2006年   15篇
  2005年   11篇
  2004年   11篇
  2003年   12篇
  2002年   8篇
  2001年   6篇
  2000年   2篇
  1999年   11篇
  1998年   12篇
  1997年   8篇
  1996年   10篇
  1995年   7篇
  1994年   8篇
  1993年   6篇
  1992年   5篇
  1991年   2篇
  1990年   5篇
  1989年   2篇
  1988年   5篇
  1987年   1篇
  1986年   4篇
  1985年   3篇
  1984年   3篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1980年   2篇
  1978年   1篇
  1977年   2篇
  1976年   1篇
  1975年   3篇
  1971年   2篇
  1968年   1篇
排序方式: 共有308条查询结果,搜索用时 171 毫秒
81.
Pervasive 2007 hosted an incredible full day of workshops before the main conference. One-hundred twenty enthusiastic participants in eight great workshops discussed experiences and ideas on particular aspects of pervasive computing with like-minded researchers and practitioners. The variety of projects presented demonstrated how truly interdisciplinary the Pervasive conference has become.  相似文献   
82.
Dual-process models of attention-deficit/hyperactivity disorder (ADHD) suggest that both executive functioning and regulatory functions (e.g., processing speed) are involved and that executive function weaknesses may be associated specifically with symptoms of inattention-disorganization but not hyperactivity-impulsivity. Adults aged 18-37 (105 with ADHD, 90 controls) completed a neuropsychological battery. The ADHD group had weaker performance than did the control group (p = .01) on both executive and speed measures. Symptoms of inattention-disorganization were uniquely related to executive functioning with hyperactivity-impulsivity controlled. Inattention was associated with slower response speed, and hyperactivity-impulsivity with faster output speed. Results were not accounted for by IQ, age, gender, education level, or comorbid disorders. Findings are discussed in terms of developmental and dual-process models of ADHD leading into adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
83.
Starches from mature, unripe fruit pulp of plantain cultivars (Musa supp., AAB group) representing the wide variability in Africa, tetraploid and diploid plantain hybrids and starchy cooking bananas (Musa spp., ABB group) were isolated and characterised. In general, studies revealed very compact irregularly shaped and sized granules, with low amylose content (9.11–17.16%), highly resistant to bacterial α-amylase attack; Brabender amylograms showed very restricted swelling type patterns with great stability and negligible retrogradation. Results indicate that differences in physico-chemical properties exist amongst the three Musa fruit group starches. Plantains represent a chemical/molecular homogeneous group, but heterogeneous for granule structure. Ploidy level affected hybrid properties. ABB cooking bananas starches exhibited highly pronounced restricted swelling and high gelatinisation and pasting temperatures, indicating a more ordered, very strongly bonded granule structure; chemical and physical properties varied considerably within the ABB genotype.  相似文献   
84.
The accuracy of databases is the subject of our survey of vendors of databases. This study examines external databases. Among the issues covered by the survey are: selection criteria for data sources, formats of data, and the approaches followed in maintaining database accuracy. One specific focus of the study is external databases for forecasting. Forecasting, as a tool of managerial planning, is sensitive to the availability and accuracy of databases. The survey results suggest that there are some practices followed by database suppliers that could produce unreliable information.  相似文献   
85.
The truncated forms of tissue inhibitor of metalloproteinase-1and -2 (TIMP-1 and -2), comprising the N-terminal active domain,are ideal molecules for structural analysis by intrinsic fluorescenceas each contains a single conserved tryptophan residue. In thispaper we describe studies on their conformational stability,unfolding/refolding kinetics and the environment of the uniquetryptophan as judged by its fluorescence properties in the nativestate and exposure to an external quencher, acrylamide. Twoforms of TIMP-2 were studied: TIMP-2 T21 derived from the full-lengthcDNA clone isolated from a mixed-tumour library, and TIMP-2A21 containing the highly conserved V18IRAK22 sequence. In allthree TIMP proteins the tryptophan environments in the nativestate appeared to be similar, but substantial differences wereseen in their conformational stabilities and refolding kinetics.TIMP-1 was approximately twice as stable as TIMP-2 T21 and 1.4-foldmore stable than TIMP-2 A21. This stability difference betweenTIMP-1 and TIMP-2 was shown to be independent of N-linked glycosylation.TTMP-1 and TIMP-2 A21 both showed simple two-state refoldingkinetics, whereas TIMP-2 T21 refolding was more complex andbiphasic in character. These differences between TIMP-2 T21and A21 suggest that residue 21 is a structurally importantsite in the TIMP protein.All three truncated molecules can beconsidered as stable independent folding domains ideally suitedfor further structural analysis  相似文献   
86.
The authors investigated factors that may determine whether perpetrators of violent crime develop intrusive memories of their offense. Of 105 young offenders who were convicted of killing or seriously harming others, 46% reported distressing intrusive memories, and 6% had posttraumatic stress disorder. Intrusions were associated with lower antisocial beliefs before the assault, greater helplessness, fear, dissociation, data-driven processing and lack of self-referent processing during the assault, more disorganized assault narratives, and greater negative view of the self, negative interpretations of intrusive memories, perceived permanent change, and self-blame. In a logistic regression analysis, the cognitive and emotional variables explained substantial variance over and above demographic factors. The results suggest that cognitive factors that predict reexperiencing symptoms in victims of crime generalize to perpetrators. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
87.
Divided 45 18–65 yr old social phobia outpatients into 3 groups of 15 Ss each: Group 1 received exposure with anxiety management. Group 2 received exposure with a nonspecific "filler" treatment instead of anxiety management. Group 3 served as a waiting-list control. Results show that Groups 1 and 2 improved more than Group 3 and the improvement was maintained for 6 mo. At the end of treatment, Group 1 had lower scores than Group 2 on 2 cognitive measures of social anxiety. Six months later, Group 1 had lower scores on 4 additional measures. No S in Group 1 requested additional treatment within a year, while 40% of Group 2 did so. It is suggested that anxiety management increases the effect of exposure treatment because it helps Ss adapt to unpredictable situations, relaxation and distraction are useful techniques, and emphasis on self-help and rationale are important. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
88.
Occurrence and significance of Bacillus thuringiensis on wine grapes   总被引:1,自引:0,他引:1  
Wine grapes harvested at different stages during cultivation from several vineyards in New South Wales, Australia, harboured Bacillus thuringiensis at viable populations of 10(2)-10(6) cfu/g. Commercial preparations of B. thuringiensis had been sprayed onto the grapes as a biological insecticide. B. thuringiensis (10(1)-10(3) cfu/ml) was isolated from grape juice and fermenting grape juice in a commercial winery. Although B. thuringiensis remained viable when inoculated at 10(3)-10(4) cfu/ml into grape juice and wine (pH 3.0-6.0), it did not grow. Using in vitro agar culture assays, B. thuringiensis inhibited several grape-associated yeasts and bacteria as well as various species of fungi associated with grape spoilage and ochratoxin A production. B. thuringiensis did not inhibit Saccharomyces cerevisiae in agar culture or during alcoholic fermentation of grape juice. B. thuringiensis inhibited the malolactic bacterium, Oenococcus oeni, in agar culture but not during mixed cultures in a liquid medium.  相似文献   
89.
The authors investigated the effect of age and time of testing on the ability to control attention and addressed the possibility that older adults' susceptibility to distraction may sometimes facilitate performance on a later cognitive task. Using a modification of a G. Rees, C. Russell, C. D. Frith, and J. Driver (1999) procedure, the authors asked the participants to make same or different judgments on line drawings superimposed with task-irrelevant letter strings. Memory for the distractors was subsequently tested with an implicit memory task. Both older and young adults demonstrated greater memory for distractors at nonoptimal times of day than at optimal times of day; however, older adults showed considerably better memory for the distractors than did young adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
90.
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