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   96篇
  免费   6篇
  国内免费   4篇
电工技术   1篇
化学工业   10篇
金属工艺   2篇
机械仪表   6篇
建筑科学   6篇
能源动力   3篇
轻工业   9篇
无线电   16篇
一般工业技术   28篇
冶金工业   10篇
自动化技术   15篇
  2023年   1篇
  2021年   4篇
  2020年   3篇
  2019年   3篇
  2018年   1篇
  2017年   2篇
  2016年   1篇
  2015年   2篇
  2014年   2篇
  2013年   5篇
  2012年   6篇
  2011年   12篇
  2010年   5篇
  2009年   8篇
  2008年   9篇
  2007年   5篇
  2006年   5篇
  2005年   6篇
  2004年   2篇
  2003年   2篇
  2002年   3篇
  2001年   2篇
  2000年   2篇
  1999年   1篇
  1998年   3篇
  1997年   3篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1991年   1篇
  1984年   1篇
  1979年   2篇
排序方式: 共有106条查询结果,搜索用时 15 毫秒
81.
Little is known about factors differentiating more and less effective therapists or the mechanisms through which therapists influence outcome. In the present study, the performance of a small sample of 4 therapists was compared in the context of delivering cognitive–behavioral psychotherapy (CBT) to 32 clients with generalized anxiety disorder. More effective therapists were characterized by higher observer-rated CBT competence, higher client outcome expectations and client treatment credibility assessments, and higher early treatment client ratings of therapeutic alliance quality. Higher early CBT competence was associated with higher client midtreatment outcome expectations, which in turn were associated with better posttreatment outcomes. Although these findings are preliminary given the small sample of therapists and clients, they suggest that the common factor of outcome expectations might be a mechanism through which the specific factor of psychotherapist competence exerts its influence on treatment outcome. The implications of these findings and directions for future research are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
82.
Quaternary‐ammonium‐compounds are potent cationic antimicrobials used in everyday consumer products. Surface‐immobilized, quaternary‐ammonium‐compounds create an antimicrobial contact‐killing coating. We describe the preparation of a shape‐adaptive, contact‐killing coating by tethering quaternary‐ammonium‐compounds onto hyperbranched polyurea coatings, able to kill adhering bacteria by partially enveloping them. Even after extensive washing, coatings caused high contact‐killing of Staphylococcus epidermidis, both in culture‐based assays and through confocal‐laser‐scanning‐microscopic examination of the membrane‐damage of adhering bacteria. In culture‐based assays, at a challenge of 1600 CFU/cm2, contact‐killing was >99.99%. The working‐mechanism of dissolved quaternary‐ammonium‐compounds is based on their interdigitation in bacterial membranes, but it is difficult to envisage how immobilized quaternary‐ammonium‐molecules can exert such a mechanism of action. Staphylococcal adhesion forces to hyperbranched quaternary‐ammonium coatings were extremely high, indicating that quaternary‐ammonium‐molecules on hyperbranched polyurea partially envelope adhering bacteria upon contact. These lethally strong adhesion forces upon adhering bacteria then cause removal of membrane lipids and eventually lead to bacterial death.  相似文献   
83.
While graphene may appear to be the ultimate support membrane for transmission electron microscopy (TEM) imaging of DNA nanostructures, very little is known if it poses an advantage over conventional carbon supports in terms of resolution and contrast. Microscopic investigations are carried out on DNA origami nanoplates that are supported onto freestanding graphene, using advanced TEM techniques, including a new dark‐field technique that is recently developed in our lab. TEM images of stained and unstained DNA origami are presented with high contrast on both graphene and amorphous carbon membranes. On graphene, the images of the origami plates show severe unwanted distortions, where the rectangular shape of the nanoplates is significantly distorted. From a number of comparative control experiments, it is demonstrated that neither staining agents, nor screening ions, nor the level of electron‐beam irradiation cause this distortion. Instead, it is suggested that origami nanoplates are distorted due to hydrophobic interaction of the DNA bases with graphene upon adsorption of the DNA origami nanoplates.  相似文献   
84.
Preferences for housing attributes have beenstudied from different theoretical perspectivesand with a great variety of methodologicalapproaches. In explaining housing preferencesthe influence of both macro-level andmicro-level factors has been shownextensively. Relatively little attention hasbeen given, though, to motivational micro-levelfactors such as goals and values. In thisarticle micro-level motivational factors arestudied as determinants of stated preferencesfor housing attributes. The relationshipsbetween such motivational factors as values andgoals on the one hand and preferences forhousing attributes on the other are consideredfrom the perspective of means-end theory. Asemi-structured interviewing technique calledladdering is used for the measurement ofmeans-end chains. Some of the results of apilot project in which means-end theory wasapplied to preferences for housing attributeswill be discussed in the sequel.  相似文献   
85.
Increasing occurrence of intrinsically antimicrobial-resistant,human pathogens and the protective biofilm-mode in which they grow,dictates a need for the alternative control of infectious biofilms.Biofilm bacteria utilize dispersal mechanisms to detach parts of a biofilm as part of the biofilm life-cycle during times of nutrient scarcity or overpopulation.We here identify recent advances and future challenges in the development of dispersants as a new infection-control strategy.Deoxyribonuclease(DNase)and other extracellular enzymes can disrupt the extracellular matrix of a biofilm to cause dispersal.Also,a variety of small molecules,reactive oxygen species,nitric oxide releasing compounds,peptides and molecules regulating signaling pathways in biofilms have been described as dispersants.On their own,dispersants do not inhibit bacterial growth or kill bacterial pathogens.Both natural,as well as artificial dispersants,are unstable and hydrophobic which necessitate their encapsulation in smart nanocarriers,like pH-responsive micelles,liposomes or hydrogels.Depending on their composition,nanoparticles can also possess intrinsic dispersant properties.Bacteria dispersed from an infectious biofilm end up in the blood circulation where they are cleared by host immune cells.However,this sudden increase in bacte-rial concentration can also cause sepsis.Simultaneous antibiotic loading of nanoparticles with dispersant properties or combined administration of dispersants and antibiotics can counter this threat.Importantly,biofilm remaining after dispersant administration appears more susceptible to existing antibiotics.Being part of the natural biofilm life-cycle,no signs of"dispersant-resistance"have been observed.Dispersants are therewith promising for the control of infectious biofilms.  相似文献   
86.
The nurturing of the adolescent patient's emerging sexuality can form the foundation for a lifelong ability to form intimate and trusting relationships. Teen pregnancy and sexually transmitted infections, the consequences of teen sexuality in crisis, impact the adolescent and our society. Psychosocial developmentally-appropriate counseling in the primary care physician's office must be part of each visit. A nonjudgmental, empathic approach is instrumental in the prevention of adolescent morbidity and mortality.  相似文献   
87.
The authors examined whether 13- to 15-year-old adolescents who experience feelings of same-sex attraction (SSA) differ from those without such feelings in the quality of relationships with parents, peers, and class mentors and in psychosocial functioning (health status and school performance). The authors also assessed whether differences in psychosocial functioning resulted from differences in the quality of social relationships. Data were collected from 866 Dutch high school students (mean age 13.61 years) by means of a computer-based questionnaire. Of the participants, 74 (8.5%) reported having feelings of SSA. The participants with SSA rated the quality of their relationships with their fathers and their peers lower than did those without SSA. Participants with SSA also had poorer mental health (higher levels of depression and lower levels of self-esteem) and lower school performance. A mediation analysis revealed that differences in psychosocial functioning resulted from differences in the quality of the same-sex attracted youths' social relationships, especially with fathers and peers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
88.
Through the mechanism of "oriented attachment", small nanocrystals can fuse into a wide variety of one- and two-dimensional nanostructures. This fusion phenomenon is investigated in detail by low-temperature annealing of a two-dimensional array of 10 nm-sized PbSe nanocrystals, in situ in the transmission electron microscope. We have revealed a complex chain of processes; after coalescence, the connected nanocrystals undergo consecutive rotations in three-dimensional space, followed by drastic interfacial relaxations whereby full fusion is obtained.  相似文献   
89.
In the Netherlands, a large ongoing study seeks to provide insight into the process behind preferences and choices with regard to moving and housing. As part of the development of the survey instrument that was used in this study, we examined whether visual images (such as photographs) should be included, since they may clarify particular attributes (e.g., architectural style) and make the choice task more realistic for the respondents. However, images may disturb the results as respondents may evaluate accidental details on the photographs such as the color of the window frames. This paper presents the results of two subsequent pilot studies on the impact of including images in a web-based questionnaire. In the first study, eight dwelling profiles were presented in three different ways (“text only”, “text and color photo” and “text and black-and-white impression”) to 28 respondents. In the second study two different instruments were used: one with written information and directly shown photo-collages; the other with written information and photo-collages on request only. Both studies showed that the inclusion of images led to a number of differences between the results obtained with the various presentation methods. These differences may be explained by accidental details on the images. Furthermore, dwelling characteristics appear to be more important to the respondents’ overall evaluation of a dwelling when shown with photos than when presented in written format. However, since including images also has a substantial number of benefits, it may not be advisable to leave out images completely from the measurement task. Should images be included in a survey instrument, it is of utmost importance to make sure that all potentially disturbing details are cleared away. Furthermore, it may be better to show a collage of pictures than only one in order to decrease the specific impact of accidental details.  相似文献   
90.
Scatter factor (SF), also known as hepatocyte growth factor, is a potent mitogen that has been suggested to exhibit greater efficacy than vascular endothelial growth factor (VEGF) in rabbits with hindlimb ischemia. Our study examined the effects of SF on cardiovascular hemodynamics and compared the responses to VEGF. Hemodynamic parameters were monitored before and after administration of SF or VEGF in conscious, instrumented rats. Intravenous injection of SF produced a dose-related reduction in mean arterial pressure (MAP) and increase in heart rate (HR). These responses were significantly attenuated by pretreatment with N omega-nitro-L-arginine methyl ester a nitric oxide (NO) synthase inhibitor, suggesting the depressor effect of SF may be mediated by NO. SF (250 micrograms/kg) reduced stroke volume and cardiac output, but did not affect the maximal first derivation of left ventricular pressure (dP/dt), suggesting that the reduction in cardiac output is caused by decreased stroke volume that probably results from a reduction in venous return. Compared with SF, VEGF produced greater hypotensive and tachycardic responses and greater reductions in stroke volume and cardiac output, indicating that SF has fewer side effects on hemodynamics. Although both growth factors might reduce venous return, SF decreased hematocrit presumably through venodilation, whereas VEGF increased hematocrit as a result of vascular hyperpermeability.  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