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   762篇
  免费   59篇
  国内免费   1篇
电工技术   5篇
化学工业   163篇
金属工艺   23篇
机械仪表   9篇
建筑科学   32篇
矿业工程   8篇
能源动力   20篇
轻工业   97篇
水利工程   10篇
石油天然气   7篇
无线电   22篇
一般工业技术   142篇
冶金工业   182篇
自动化技术   102篇
  2023年   8篇
  2022年   8篇
  2021年   38篇
  2020年   29篇
  2019年   31篇
  2018年   26篇
  2017年   29篇
  2016年   16篇
  2015年   21篇
  2014年   42篇
  2013年   49篇
  2012年   44篇
  2011年   62篇
  2010年   48篇
  2009年   37篇
  2008年   43篇
  2007年   31篇
  2006年   26篇
  2005年   17篇
  2004年   20篇
  2003年   18篇
  2002年   13篇
  2001年   7篇
  2000年   8篇
  1999年   8篇
  1998年   10篇
  1997年   12篇
  1996年   6篇
  1995年   3篇
  1994年   4篇
  1993年   5篇
  1992年   6篇
  1991年   6篇
  1990年   9篇
  1989年   9篇
  1988年   9篇
  1987年   2篇
  1986年   3篇
  1985年   9篇
  1984年   12篇
  1983年   2篇
  1982年   2篇
  1980年   5篇
  1978年   3篇
  1977年   2篇
  1976年   4篇
  1973年   3篇
  1972年   2篇
  1970年   3篇
  1968年   3篇
排序方式: 共有822条查询结果,搜索用时 31 毫秒
1.
Antibiotic resistance is a growing problem for public health and associated with increasing economic costs and mortality rates. Silver and silver-related compounds have been used for centuries due to their antimicrobial properties. In this work, we show that 1,3-dibenzyl-4,5-diphenyl-imidazol-2-ylidene silver(I) acetate/NHC*-Ag-OAc (SBC3) is a reversible, high affinity inhibitor of E. coli thioredoxin reductase (TrxR; Ki=10.8±1.2 nM). Minimal inhibition concentration (MIC) tests with different E. coli and P. aeruginosa strains demonstrated that SBC3 can efficiently inhibit bacterial cell growth, especially in combination with established antibiotics like gentamicin. Our results show that SBC3 is a promising antibiotic drug candidate targeting bacterial TrxR.  相似文献   
2.
3.
Deals with the use of neural networks to solve linear and nonlinear programming problems. The dynamics of these networks are analyzed. In particular, the dynamics of the canonical nonlinear programming circuit are analyzed. The circuit is shown to be a gradient system that seeks to minimize an unconstrained energy function that can be viewed as a penalty method approximation of the original problem. Next, the implementations that correspond to the dynamical canonical nonlinear programming circuit are examined. It is shown that the energy function that the system seeks to minimize is different than that of the canonical circuit, due to the saturation limits of op-amps in the circuit. It is also noted that this difference can cause the circuit to converge to a different state than the dynamical canonical circuit. To remedy this problem, a new circuit implementation is proposed.  相似文献   
4.
Addressed conflicting views of depressives' interpersonal accuracy in an investigation of the accuracy of mild depressives (dysphorics) across differing social contexts. Women who were either friends or strangers and who were either similar or dissimilar in level of dysphoria conversed about 3 topics: a neutral topic, their own disclosure of a personal problem, and their partner's disclosure. Dysphorics were not more accurate in general than nondysphorics. After self-disclosure, all women more accurately detected sympathy from a similar stranger. After the partner's disclosure, women also better detected the mood of a similar partner. When interacting with nondysphoric strangers, however, dysphorics underestimated their partner's sympathy toward them. Implications for cognitive and interpersonal theories of depression and for depressives' relationships are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
The variability of most environments taxes foraging decisions by increasing the uncertainty of the information available. One solution to the problem is to use dynamic averaging, as do some granivores and carnivores. Arguably, the same strategy could be useful for grazing herbivores, even though their food renews and is more homogeneously distributed. Horses (Equus callabus) were given choices between variable patches after short or long delays. When patch information was current, horses returned to the patch that was recently best, whereas those without current information matched choices to the long-term average values of the patches. These results demonstrate that a grazing species uses dynamic averaging and indicate that, like granivores and carnivores, they can use temporal weighting to optimize foraging decisions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
An improved inductive transducer is achieved by placing the coil and the majority of the transducer body into a recessed alumina basecoat. Process advantages of a recessed over planar structure includes lower top pole topography, improved pole trim capability, and improved top pole composition uniformity. Coil and photoresist processing in a recessed cavity allows for multiple layers with lower resistance without increasing transducer Permalloy path length. Recessed trimmed design performance has increased efficiency with higher amplitude and a narrower pulse width along with improved overwrite compared to planar untrimmed transducers. The recessed basecoat design is explained, and compared to planar transducers using modeling and performance results  相似文献   
7.
Adult rats that were isolated from the mother and nest for 1 hr per day from Postnatal Day 2 to 9 were studied. Controls consisted of handled littermates as well as separate litters that were never handled. As adults, animals were given either a pharmacological challenge (1.0 or 2.0 mg/kg amphetamine) or an environmental challenge (restraint). Previously isolated animals demonstrated increased activity compared to controls at both drug doses. Similarly, isolated animals manifested exaggerated inhibition of activity after restraint. Previously isolated animals usually did not show differences compared to controls under baseline conditions (saline injection or no restraint). The neuroplastic changes that result from the neonatal experience are long lasting and appear when the system is challenged. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
8.
Liu  Xinke  Kao  Evan  Haraldsson  Henrik  Ballweber  Megan  Martin  Alastair  Li  Youxiang  Wang  Yuting  Saloner  David 《Magma (New York, N.Y.)》2021,34(5):659-666
Magnetic Resonance Materials in Physics, Biology and Medicine - To determine the intra-individual flow variation in serially acquired studies, and the influence of this variation on subsequent...  相似文献   
9.
As digital interfaces increasingly mediate our access to information, the design of these interfaces becomes increasingly important. Designing digital interfaces requires writers to make rhetorical choices that are sometimes technical in nature and often correspond with principles taught in the computer science subfield of human-computer interaction. We propose that an HCI-informed writing pedagogy can complicate for both writing and computer science students the important role audience should play when designing traditional and digital interfaces. Although it is a subtle shift in many ways, this pedagogy seemed to complicate student understanding of the relationship between audience and the texts/interfaces they created: it was not just the “human” (beliefs, attitudes, values, demographics) or the “computer” (the software or hardware or other types of mediation) that mattered but rather the “interaction” between the two. First we explore some of the ways in which writing code and writing prose have merged and paved the way for an HCI-informed writing pedagogy. Next we examine some parallels between human-computer interaction principles and composition principles. Finally, we refer to assignments, student responses, and anecdotal evidence from our classes where an HCI-informed writing pedagogy drew—or could have drawn—student attention more acutely to various audience-related technical and rhetorical interface design choices.  相似文献   
10.
Upconverting nanoparticles show potential applications in the field of photovoltaics and array‐based detection devices. While fluorescence enhancement using interference of incident radiation is well known in Stokes‐shift type systems such as fluorescent dyes; the effect of such interference geometry in nonlinear Anti‐Stokes type emission, such as in upconversion rare earth photophysics is demonstrated for the first time. This work describes in detail the influence of the interference modulation on both the excitation (interion energy transfer) and radiative decay with nonradiative decay processes active between emissive levels. These effects are illustrated in the thickness dependence of the decay rate and rise time. Single particle upconverted spectra and time‐resolved measurements show concurrent optimization of the infrared absorption and emission at 540 and 650 nm, with an average enhanced emission of 20 times at λ = 540 and 45 times at λ = 650 nm, dependent on the interference layer thickness and on the excitation intensity. The experimental results are correlated with finite element modeling. Both experiments and calculations show emission enhancement at an interference layer thickness of about 740 ± 20 nm, where such tolerance and the planar design, leads to ease in implementation in applications.  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