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991.
The role of the central nucleus of the amygdala on olfactory heart rate conditioning in the infant rat was investigated. The conditioned stimulus (CS) consisted of a 10-s presentation of grape juice odor that was immediately followed by a 0.5-s, 0.35-mA subcutaneous shock. A sensitization control group was also run. Three days prior to testing, Ss received either bilateral electrolytic lesions of the central nucleus of the amygdala, sham lesions, or were left unperturbed. Results show that damage to the central nucleus of the amygdala severely impaired olfactory heart rate conditioning but that it had no deleterious effect on the heart rate orienting response to that stimulus or on the heart rate unconditioned response (UCR) to shock. Results are analogous to those in previous research on auditory heart rate conditioning and suggest that the central nucleus of the amygdala may constitute a necessary stage in the transduction of the CS into a cardiac conditioned response (CR) regardless of sensory modality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
992.
Under certain conditions, some microorganisms are able to synthesize surface active compounds called biosurfactants (BS), which reduce the surface tension of water. BS characteristics depend on which microorganism produce them and therefore, on the microorganism culture conditions (temperature, pH, C, N-source,…). Numerous applications are known for these biomolecules, such as cleaning, bioremediation, and their use as a detergent, or in cosmetic formulations.Recently, a large amount of literature has been edited on the influence of BS on the interactions between pathogenic bacteria and inert surfaces. It has been shown that the modifications of surface properties by the adsorption of BS can reduce microbial adhesion.Some other studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; they are indeed used as an interesting corrosion inhibition tool. Therefore, it seems very interesting to study the impact of BS as environment-friendly (since biological and biodegradable) corrosion inhibitors.In the present work, an attempt was made to study the corrosion behaviour of AISI 304 stainless steel in presence of BS produced by a Gram-negative bacteria, Pseudomonas fluorescens (Pf495). Corrosion tests were achieved on several surface oxidation states. The surface morphology of the corroded specimens was investigated using SEM.  相似文献   
993.
Computer-aided software engineering (CASE) methodology and tools play an important role in the development of information systems and in the future direction of CASE. The amount of available information on this topic can be overwhelming. This article presents guidelines on selecting tools and a methodology based on the experience of the systems development team at Howard Hughes Medical Institute (HHMI), where CASE has been successfully implemented.  相似文献   
994.
Electroencephalogram (EEG) alpha (8-12 Hz) asymmetries were collected from the mid-frontal and central regions during presleep wakefulness and Stage 1, Stage 2, and rapid eye movement (REM) sleep in 11 healthy right-handed participants who were free of psychiatric, neurological, and sleep problems. The authors found significant correlations between presleep wakefulness and different stages of sleep in the frontal, but not central, EEG alpha asymmetry measure. The strongest correlation was between presleep waking and REM sleep, replicating and extending relation earlier work to a normal population. The high degree of association between presleep waking and REM sleep may be a result of high cortical activation common to these states and may reflect a predisposition to different styles of emotional reactivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
995.
Odor mixture perception can be configural (the mixture is qualitatively different from the components) or elemental (the components are recognizable). Some have argued that configural properties are dependent on chemical similarity and possible overlap at the receptor level. The authors show that a binary mixture in which both components activate the same receptor (17) has a configural odor, whereas a mixture that suppresses overlap has elemental odor properties. Rats trained to recognize mixtures of citronellal and octanal (strong 17 agonists) in many ratios rarely recognize the components, supporting configural representation of the odor mixture. However, when trained to recognize mixtures of citral (partial 17 agonist, inhibitor) and octanal, rats recognize 1 or both components over a wide range of ratios. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
996.
This research extends previous work indicating that individuals are more effective at regulating their behavior when they are in goal-congruent contexts by examining whether individuals particularly need concrete goal-relevant situational affordances once they are in these broadly affirming contexts. Specifically, the authors explore this issue by using the broad context of steady dating relationships (i.e., intimacy-relevant contexts), and considering the role of both intimacy goals and intimacy-affording daily life situations in producing relationship satisfaction and maintenance over time. Results indicate that those with a strong focus on intimacy experience considerable relationship satisfaction regardless of whether they spend time in daily life situations that facilitate intimacy, whereas those without such a focus depend for satisfaction on the presence of intimacy-conducive situations (e.g., time alone with one's partner, or social support from one's partner). Discussion focuses on the theoretical implications of these findings for the Person x Situation literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
997.
Studied cooperation from a group process perspective within the free play of children aged 2, 3, and 4 yrs. 72 children were distributed among 12 groups, with 3 boys and 3 girls in each group and 4 groups in each age. Two 30-min sessions were videotaped for each group to assess dimensions of cooperation such as the number of children in each subgroup, kind of play, and type of activity. Observational analyses showed that cooperation is present at every age but may develop rapidly at certain ages and plateau at others. Furthermore, results suggest that group play is not the culmination of a linear developmental process. Modifications in quantity between the 2 youngest and the oldest group suggest a cooperation continuum of its own, with large variations between groups within each age group. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
998.
Without global legislation to combat spam, the problem will never be solved despite the fact that it is costs global businesses millions of dollars a year to tackle, believes the security industry.  相似文献   
999.
Discrete element methods are important tools for the investigation of the mechanics of granular materials. In two dimensions, the reliability of these numerical approaches can be explored using physical tests on rod assemblies. This work highlights the importance of representing the actual distribution of rod shapes and surface friction in numerical simulations. The sensitivity of the response of hexagonally packed rods to minor changes in particle geometry and friction is investigated using a combination of laboratory tests and discrete element simulations. Laboratory test results highlight the influence of small variations in rod geometry on the global response, with the peak friction angle decreasing significantly as the standard deviation of the rod size distribution increased. Small changes in rod shape are also seen to be important. The numerical simulations indicate that the peak friction angle decreases as the standard deviation of the distribution of particle surface friction increases. This paper illustrates the way in which laboratory tests and numerical simulations can be used in a complementary manner to better understand the micromechanics of the response of granular materials.  相似文献   
1000.
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