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41.
The rising demand and cost of software have prompted researchers to investigate factors associated with program changes in software systems. Numerous program complexity measures and statistical techniques have been used to study the effects of program complexity on program changes. The effects of programming methodology on the relationship of complexity to program changes were measured in this study. The results suggest that the relationship of length and structure complexity characteristics to program changes is consistent for different programming methodologies, while the relationship of program changes and characteristics that relate to the use of data and procedure names is not consistent for different programming methodologies.  相似文献   
42.
1. The effect of Mytilus inhibitory peptide-related peptide RAPYFVamide, isolated from Helix pomatia brain, was studied on 21 different identified Helix neurons. 2. It was found that the neuropeptide hyperpolarized 11 of the 21 neurons studied, inducing a K-dependent current. Not all neurons responded by hyperpolarization to the peptide application, though, in all cases the voltage-dependent outward K and inward Ca currents were depressed. 3. This may show that, in the peptide effect, more than one type of K conductance is involved. 4. It is proposed that RAPYFVamide may have a functional role in the modulation of the feeding behavior in H. pomatia.  相似文献   
43.
Developing error-free software requirements is of critical importance to the success of a software project. Problems that occur during requirements collection and specification, if not fixed early, are costly to fix later. Therefore, it is important to develop techniques that help requirements engineers detect and prevent requirements problems. As a human-centric activity, requirements engineering can be influenced by psychological research about human errors, which are the failings of human cognition during the process of planning and executinge a task. We have employed human error research to describe the types of problems that occur during requirements engineering. The goals of this research are: (1) to evaluate whether understanding human errors contributes to the prevention of errors and concomitant faults during requirements engineering and (2) to identify error prevention techniques used in industrial practice. We conducted a controlled classroom experiment to evaluate the benefits that knowledge of errors has on error prevention. We then analyzed data from two industrial surveys to identify specific prevention and mitigation approaches employed in practice. The classroom study showed that the better a requirements engineer understands human errors, the fewer errors and concomitant faults that engineer makes when developing a new requirements document. Furthermore, different types of Human Errors have different impacts on fault prevention. The industry study results identified prevention and mitigation mechanisms for each error type. Human error information is useful for fault prevention during requirements engineering. There are practices that requirements engineers can employ to prevent or mitigate specific human errors.  相似文献   
44.
Evidence from diverse literatures supports the viewpoint that two modes of self-regulation exist, a lower-order system that responds quickly to associative cues of the moment and a higher-order system that responds more reflectively and planfully; that low serotonergic function is linked to relative dominance of the lower-order system; that how dominance of the lower-order system is manifested depends on additional variables; and that low serotonergic function therefore can promote behavioral patterns as divergent as impulsive aggression and lethargic depression. Literatures reviewed include work on two-mode models; studies of brain function supporting the biological plausibility of the two-mode view and the involvement of serotonergic pathways in functions pertaining to it; and studies relating low serotonergic function to impulsiveness, aggression (including extreme violence), aspects of personality, and depression vulnerability. Substantial differences between depression and other phenomena reviewed are interpreted by proposing that depression reflects both low serotonergic function and low reward sensitivity. The article closes with brief consideration of the idea that low serotonergic function relates to even more diverse phenomena, whose natures depend in part on sensitivities of other systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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46.
One approach to testing concurrent programs, called reachability testing, generates synchronization sequences automatically and on-the-fly, without constructing any static models. In this paper, we present a general execution model for concurrent programs that allows reachability testing to be applied to several commonly used synchronization constructs. We also present a new method for performing reachability testing. This new method guarantees that every partially ordered synchronization sequence will be exercised exactly once without having to save any sequences that have already been exercised. We describe a prototype reachability testing tool called RichTest and report some empirical results, including a comparison between RichTest and a partial order reduction-based tool called VeriSoft. RichTest performed significantly better for the programs in our study.  相似文献   
47.
Oxidation of the neurotransmitter, dopamine (DA), is a pathological hallmark of Parkinson’s disease (PD). Oxidized DA forms adducts with proteins which can alter their functionality. αB-crystallin and Hsp27 are intracellular, small heat-shock molecular chaperone proteins (sHsps) which form the first line of defense to prevent protein aggregation under conditions of cellular stress. In vitro, the effects of oxidized DA on the structure and function of αB-crystallin and Hsp27 were investigated. Oxidized DA promoted the cross-linking of αB-crystallin and Hsp27 to form well-defined dimer, trimer, tetramer, etc., species, as monitored by SDS-PAGE. Lysine residues were involved in the cross-links. The secondary structure of the sHsps was not altered significantly upon cross-linking with oxidized DA but their oligomeric size was increased. When modified with a molar equivalent of DA, sHsp chaperone functionality was largely retained in preventing both amorphous and amyloid fibrillar aggregation, including fibril formation of mutant (A53T) α-synuclein, a protein whose aggregation is associated with autosomal PD. In the main, higher levels of sHsp modification with DA led to a reduction in chaperone effectiveness. In vivo, DA is sequestered into acidic vesicles to prevent its oxidation and, intracellularly, oxidation is minimized by mM levels of the antioxidant, glutathione. In vitro, acidic pH and glutathione prevented the formation of oxidized DA-induced cross-linking of the sHsps. Oxidized DA-modified αB-crystallin and Hsp27 were not cytotoxic. In a cellular context, retention of significant chaperone functionality by mildly oxidized DA-modified sHsps would contribute to proteostasis by preventing protein aggregation (particularly of α-synuclein) that is associated with PD.  相似文献   
48.
给出了单电源ADC的直流耦合单端到差分缓冲器电路.  相似文献   
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50.
C. S. Carver and E. Harmon-Jones (see record 2009-02580-003) reviewed evidence consistent with the idea that anger arises from a behavioral approach system. Commentary on that article by A. J. Tomarken and D. H. Zald (see record 2009-02580-005) raised questions about the many elements involved in acts of approach and limitations on what information can be provided by electroencephalograms. Commentary by D. Watson (see record 2009-02580-004) raised questions about the extensive psychometric evidence linking the negative affects. This article responds briefly to these issues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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