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281.
Within a second of seeing an emotional facial expression, people typically match that expression. These rapid facial reactions (RFRs), often termed mimicry, are implicated in emotional contagion, social perception, and embodied affect, yet ambiguity remains regarding the mechanism(s) involved. Two studies evaluated whether RFRs to faces are solely nonaffective motor responses or whether emotional processes are involved. Brow (corrugator, related to anger) and forehead (frontalis, related to fear) activity were recorded using facial electromyography (EMG) while undergraduates in two conditions (fear induction vs. neutral) viewed fear, anger, and neutral facial expressions. As predicted, fear induction increased fear expressions to angry faces within 1000 ms of exposure, demonstrating an emotional component of RFRs. This did not merely reflect increased fear from the induction, because responses to neutral faces were unaffected. Considering RFRs to be merely nonaffective automatic reactions is inaccurate. RFRs are not purely motor mimicry; emotion influences early facial responses to faces. The relevance of these data to emotional contagion, autism, and the mirror system-based perspectives on imitation is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
282.
Software developers rely on a build system to compile their source code changes and produce deliverables for testing and deployment. Since the full build of large software systems can take hours, the incremental build is a cornerstone of modern build systems. Incremental builds should only recompile deliverables whose dependencies have been changed by a developer. However, in many organizations, such dependencies still are identified by build rules that are specified and maintained (mostly) manually, typically using technologies like make. Incomplete rules lead to unspecified dependencies that can prevent certain deliverables from being rebuilt, yielding incomplete results, which leave sources and deliverables out-of-sync. In this paper, we present a case study on unspecified dependencies in the make-based build systems of the glib, openldap, linux and qt open source projects. To uncover unspecified dependencies in make-based build systems, we use an approach that combines a conceptual model of the dependencies specified in the build system with a concrete model of the files and processes that are actually exercised during the build. Our approach provides an overview of the dependencies that are used throughout the build system and reveals unspecified dependencies that are not yet expressed in the build system rules. During our analysis, we find that unspecified dependencies are common. We identify 6 common causes in more than 1.2 million unspecified dependencies.  相似文献   
283.
Explored the findings of D. A. Lieberman et al (see record 1980-27237-001) who showed that 2-choice spatial discrimination by rats is enhanced if a salient stimulus marker occurs immediately after every choice response and again after a delay interval. In the present study, 3 experiments were conducted with 72 male hooded rats. Ss were rewarded for running to the white arm of a maze that was grey, black, and white. Noise was used as the marker. Exp I found that the 2nd marker was unnecessary. Exp II found that a marker presented before a response was as effective as one presented after. Both effects could be explained in terms of markers focusing attention on subsequent cues. Exp III, however, found that markers after choice enhanced learning even when no discriminative cues were present following the marker. Markers thus appear to initiate both a backward search through memory and attention to subsequent events; both processes help to identify events that might be related to the unexpected marking stimulus. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
284.

Background  

The consumption of foods, especially by children, may be determined by the types of foods that are available in the home. Because most studies use a single point of data collection to determine the types of foods in the home, which can miss the change in availability when resources are not available, the primary objective of this study was to determine the extent to which the weekly availability of household food items changed over one month by 1) developing the methodology for the direct observation of the presence and amount of food items in the home; 2) conducting five in-home household food inventories over a thirty-day period in a small convenience sample; and 3) determining the frequency that food items were present in the participating households.  相似文献   
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287.
Fluoride cycling within a smelter has been examined as a function of alumina properties. Using an experimental configuration in which the two ends of a single potline were operated with different aluminas, quantitative measurements were made of fluoride evolution from the pots, and hydrogen fluoride (HF) levels at the scrubber and stack. Correlations were then examined with specific alumina properties, once environmental factors and other baseline effects had been considered. Although the phase analysis, including both residual gibbsite and alumina structural hydroxide content, is correlated with HF generation, local weather conditions (primarily humidity) also have a major influence on fluoride evolution. Importantly, HF concentrations at the scrubber (measured in the gas phase at the outlet to the gas treatment center), as a proxy for the kinetics of the scrubbing process, support the importance of alumina pore size distribution as opposed to simply specific surface area. This is also found to be true in the independent analysis of bath acidity, indicating a more general but extremely important influence of alumina porosity on the entire fluoride cycle. The study provides insight into the impacts of a range of typically unreported alumina properties on smelter performance and strongly supports the presence of kinetically inaccessible porosity in pores narrower than ~3 nm in alumina.  相似文献   
288.
We investigated the hypothesis that wood-boring beetles in the genus Monochamus (Cerambycidae) utilize pheromones of sympatric bark beetles as host-finding kairomones. All nine bark beetle pheromones tested electrophysiologically were antenally active for both sexes of M. scutellatus, M. clamator, and M. obtusus from British Columbia. When field-tested with multiple-funnel traps (British Columbia) or cross-vane traps (Ontario), a blend composed of frontalin, ipsdienol, ipsenol, and MCH, in combination with a blend of host volatiles attracted significant numbers of M. clamator, M. obtusus, M. notatus, and M. scutellatus to baited traps. Traps baited with host volatiles in combination with a second blend composed of endo-brevicomin, exo-brevicomin, cis-verbenol, trans-verbenol, and verbenone caught no more beetles than unbaited traps or traps baited with the host blend alone. In British Columbia, traps baited with the first blend alone or both blends together captured more M. scutellatus and M. clamator than unbaited traps, demonstrating a response to bark beetle pheromones in the absence of host volatiles. These results suggest that Monochamus spp. are minimizing foraging costs by using the pheromones of sympatric bark beetles as kairomones.  相似文献   
289.
BACKGROUND: Prehydrolysis of wheat stubble using moderate temperatures and dilute acid strength is an effective means for solubilizing hemicellulose fractions and improving cellulose hydrolysis. Variation in prehydrolysis parameters (temperature, time, and acid strength) and enzymatic saccharification conditions were examined for conversion of wheat stubble into fermentable sugars. RESULTS: Elevating temperature and acid strength maximized sugar release in prehydrolysate liquors. The optimal conditions of 2.0% H2SO4/60 min/121 °C effectively solubilized 79% of the available hemicellulose. Production of inhibitory hydrolysis and degradation products such as acetic acid and levulinic acid, were detected at levels of 3.4 g L?1 and 0.64 g L?1, respectively. Sugar yields in prehydrolysate and saccharified liquors were found to increase with treatment severity. Temperature had the greatest impact on sugar release, followed by acid concentration and time. Optimizing prehydrolysis conditions at 1.0% H2SO4/90 min/121 °C, produced a 3.2‐fold improvement in cellulose hydrolysis with recoveries approaching 82%. The addition of β‐glucosidase and xylanase to the cellulase preparations assisted monomeric sugar release. CONCLUSION: Although treatment conditions for hemicellulose and cellulose hydrolysis differ, the study's findings suggest a good degree of overlap and process flexibility which should permit high recovery of pentose and hexose sugars. Copyright © 2011 Society of Chemical Industry  相似文献   
290.
Defatted meals and protein concentrates from five varieties of mustard seeds (four Brassica spp. and one Sinapis alba) were analyzed for polypeptide composition and functional properties. Nonreducing gel electrophoresis showed that Brassica seeds lacked the 135- and 50-kDa polypeptides that were present in the seeds of the S. alba variety. On the other hand, the 29-kDa polypeptide found in the Brassica seeds was absent from the seed of the S. alba variety. Under reducing conditions, the 135 kDa was not detected in the S. alba variety and the intensity of the 50-kDa polypeptide was severely reduced; in contrast, the intensity of the 29-kDa polypeptide in the Brassica seeds was not affected. Meals from yellow seeds had significantly higher (P≤0.05) protein contents than meals from the brown seeds. The emulsifying activity indexes (EAI) of meals and protein concentrates from the Brassica seeds were significantly higher (P≤0.05) than those obtained for similar products from S. alba sees. It was concluded that the disulfide-bonded 50- and 135-kDa polypeptides may have contributed to increased rigidity of S. alba meal proteins, which resulted in poor EAI when compared to the Brassica meals, which do not contain these polypeptides.  相似文献   
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