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   199篇
  免费   16篇
电工技术   1篇
化学工业   61篇
机械仪表   5篇
建筑科学   17篇
矿业工程   1篇
能源动力   4篇
轻工业   25篇
无线电   14篇
一般工业技术   31篇
冶金工业   43篇
自动化技术   13篇
  2024年   1篇
  2023年   5篇
  2022年   3篇
  2021年   10篇
  2020年   8篇
  2019年   2篇
  2018年   2篇
  2017年   5篇
  2016年   7篇
  2015年   11篇
  2014年   7篇
  2013年   14篇
  2012年   6篇
  2011年   16篇
  2010年   11篇
  2009年   12篇
  2008年   8篇
  2007年   13篇
  2006年   7篇
  2005年   6篇
  2004年   4篇
  2003年   6篇
  2002年   2篇
  2000年   3篇
  1999年   3篇
  1998年   2篇
  1997年   3篇
  1996年   2篇
  1995年   3篇
  1994年   1篇
  1992年   4篇
  1990年   1篇
  1989年   3篇
  1988年   1篇
  1986年   2篇
  1985年   3篇
  1984年   2篇
  1982年   2篇
  1981年   2篇
  1978年   2篇
  1977年   3篇
  1976年   1篇
  1975年   2篇
  1973年   1篇
  1943年   2篇
  1929年   1篇
排序方式: 共有215条查询结果,搜索用时 17 毫秒
61.
Simulation of covert pain, as reported by the hidden observer method, proved very successful for 12 simulator Ss known to be unable to reduce overtly reported pain through hypnotic analgesia procedures, as compared with 12 highly hypnotizable Ss whose pain had been shown to be reduced by at least one third through hypnotic analgesia suggestions. Preliminary practice in dissociation (and in simulated dissociation) through amnesia for a word list and through attempted automatic writing also demonstrated successful simulation. However, in an honesty inquiry by a staff member not participating as a hypnotist-experimenter, no simulator claimed to have been amnesic, to have performed automatic writing, or to have reduced pain beyond the reduction that could be achieved through waking suggestion. The methods by which the successful simulation was achieved were explored in subsequent interviews. In contrast with the simulators, no highly hypnotizable S modified any earlier report on the basis of the honesty inquiry. Results confirm the importance of postexperimental honesty interrogation when the real–simulator design is used. Results also lend support to the reality of the covert experience of pain in the absence of its overt experience in hypnotic analgesia. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
62.
63.
64.
Research field trials of fully functional prototypes of location-based games are an effective way to test game designs and develop an understanding of what makes games compelling. They may also expose emergent behaviors or facets of the game which were not predicted in the design. Experiments are a good way to explore these emergent behaviors in a rigorous way. We describe an emergence-driven research methodology that formalizes this process of using emergent phenomena from research field trials to drive experiments. We also describe a range of techniques that can be used to evaluate location aware experiences.  相似文献   
65.
The electronic structure of low temperature, solution‐processed indium–zinc oxide thin‐film transistors is complex and remains insufficiently understood. As commonly observed, high device performance with mobility >1 cm2 V?1 s?1 is achievable after annealing in air above typically 250 °C but performance decreases rapidly when annealing temperatures ≤200 °C are used. Here, the electronic structure of low temperature, solution‐processed oxide thin films as a function of annealing temperature and environment using a combination of X‐ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and photothermal deflection spectroscopy is investigated. The drop‐off in performance at temperatures ≤200 °C to incomplete conversion of metal hydroxide species into the fully coordinated oxide is attributed. The effect of an additional vacuum annealing step, which is beneficial if performed for short times at low temperatures, but leads to catastrophic device failure if performed at too high temperatures or for too long is also investigated. Evidence is found that during vacuum annealing, the workfunction increases and a large concentration of sub‐bandgap defect states (re)appears. These results demonstrate that good devices can only be achieved in low temperature, solution‐processed oxides if a significant concentration of acceptor states below the conduction band minimum is compensated or passivated by shallow hydrogen and oxygen vacancy‐induced donor levels.  相似文献   
66.
High-quality Cd0.5Zn0.5Se nanoparticles with diameters ranging from 2.6 to 4.3 nm were synthesized via intensive mechanical milling for up to 20 h. The full width at half maximum (FWHM) and broadening of the diffraction peaks increased with increasing ball milling process and later decreased. XRD pattern confirmed a dominant zinc blende phase at (x = 0.5) composition. The optical spectra of the nanoparticles exhibited an onset absorption peak at 349 nm, with maximum absorption at 290 nm. The luminescence properties of the nanoparticles at room temperature were analyzed via photoluminescence spectroscopy, revealing band-edge emission at 354 nm. Photoluminescence (PL) spectra exhibit broad emission band at the range of (380–508) nm photon energy. The PL spectrum has two distinctive shoulders at 403 and 450 nm. Band emissions of 1.74, 1.54 and 1.4 eV at longer wavelengths that were associated with the surface state were also observed. High-transmission electron microscopy (HRTEM) revealed the successful annihilation of such defects with continuous milling.  相似文献   
67.
This study was designed to empirically assess the potential of microcomputer-based intervention with black adolescents from economically disadvantaged backgrounds. Subjects were 26, 11 through 14-year-old black females and males recruited from three boroughs in New York City. A sample task was administered via microcomputer system followed by a postintervention measurement battery. Observational measures were also employed to assess interactional variables. Subjects' attitudes toward educational content in general, and toward drug and alcohol information delivery in particular, appeared to be a significant intervening variable that could alter the overall efficacy of computer-delivered interventions. Both observational and postintervention measures indicated an overall positive subject response to computer-administered instruction. In contrast, however, respondents indicated a negative response to microcomputer delivery of drug and alcohol related materials. Results of the experiment are discussed along with rationales and future research directions.  相似文献   
68.
TiO2 doped with various loadings of nitrogen was prepared by nitridation of a nano-TiO2 powder in an ammonia/argon atmosphere at a range of temperatures from 400 to 1100 °C. The nano-TiO2 starting powder was produced in a continuous hydrothermal flow synthesis (CHFS) process involving reaction between a flow of supercritical water and an aqueous solution of a titanium salt. The structures of the resulting nanocatalysts were investigated using powder X-ray diffraction (XRD) and Raman spectroscopy. Products ranging from N-doped anatase TiO2 to phase-pure titanium nitride (TiN) were obtained depending on post-synthesis heat-treatment temperature. The results suggest that TiN started forming when the TiO2 was heat-treated at 800 °C, and that pure phase TiN was obtained at 1000 °C after 5 h nitridation. The amounts and nature of the Ti, O and N at the surface were determined by X-ray photoelectron spectroscopy (XPS). A shift of the band-gap to lower energy and increasing absorption in the visible light region, were observed by increasing the heat-treatment temperature from 400 to 700 °C.  相似文献   
69.
Alpha-synuclein (α-syn) and leucine-rich repeat kinase 2 (LRRK2) play crucial roles in Parkinson’s disease (PD). They may functionally interact to induce the degeneration of dopaminergic (DA) neurons via mechanisms that are not yet fully understood. We previously showed that the C-terminal portion of LRRK2 (ΔLRRK2) with the G2019S mutation (ΔLRRK2G2019S) was sufficient to induce neurodegeneration of DA neurons in vivo, suggesting that mutated LRRK2 induces neurotoxicity through mechanisms that are (i) independent of the N-terminal domains and (ii) “cell-autonomous”. Here, we explored whether ΔLRRK2G2019S could modify α-syn toxicity through these two mechanisms. We used a co-transduction approach in rats with AAV vectors encoding ΔLRRK2G2019S or its “dead” kinase form, ΔLRRK2DK, and human α-syn with the A53T mutation (AAV-α-synA53T). Behavioral and histological evaluations were performed at 6- and 15-weeks post-injection. Results showed that neither form of ΔLRRK2 alone induced the degeneration of neurons at these post-injection time points. By contrast, injection of AAV-α-synA53T alone resulted in motor signs and degeneration of DA neurons. Co-injection of AAV-α-synA53T with AAV-ΔLRRK2G2019S induced DA neuron degeneration that was significantly higher than that induced by AAV-α-synA53T alone or with AAV-ΔLRRK2DK. Thus, mutated α-syn neurotoxicity can be enhanced by the C-terminal domain of LRRK2G2019 alone, through cell-autonomous mechanisms.  相似文献   
70.
Integrating diverse energy sources to produce cost‐competitive fuels requires efficient resource management. An optimization framework is proposed for a nationwide energy supply chain network using hybrid coal, biomass, and natural gas to liquids (CBGTL) facilities, which are individually optimized with simultaneous heat, power, and water integration using 162 distinct combinations of feedstock types, capacities, and carbon conversion levels. The model integrates the upstream and downstream operations of the facilities, incorporating the delivery of feedstocks, fuel products, electricity supply, water, and CO2 sequestration, with their geographical distributions. Quantitative economic trade‐offs are established between supply chain configurations that (a) replace petroleum‐based fuels by 100%, 75%, and 50% and (b) utilize the current energy infrastructures. Results suggest that cost‐competitive fuels for the US transportation sector can be produced using domestically available coal, natural gas, and sustainably harvested biomass via an optimal network of CBGTL plants with significant GHG emissions reduction from petroleum‐based processes. © 2012 American Institute of Chemical Engineers AIChE J, 2012  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