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31.
Martin Terrell 《Microprocessors and Microsystems》1983,7(1):33-36
Device sophistication and data-processing ability continue to grow steadily and new processing devices dedicated to special functions such as speech processing or data encryption are regularly being introduced or replaced by more powerful devices. As device manufacturers extend the power and applicability of devices, new system design concepts are needed. Not only are specialist disciplines required but also the question of integration arises, a problem, all too easily overlooked. This paper looks at the problems caused by increased complexity (such as in two-sided cards on buses) and puts forward suggestions as to how to improve reliability, such as protecting the system clock and limiting the amount of parallel I/O, at least on the system card. 相似文献
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33.
Breeder-reactor fuel-cycle analysis can be divided into four different areas or categories. The first category concerns questions about the spatial variation of the fuel composition for single loading intervals. Questions of the variations in the fuel composition over several cycles represent a second category. Third, there is a need for a determination of the breeding capability of the reactor. The fourth category concerns the investigation of breeding and long-term fuel logistics. Two fuel-cycle models used to answer questions in the third and fourth area are presented.The space- and time-dependent actinide balance, coupled with criticality and fuel-management constraints, is the basis for both the Discontinuous Integrated Fuel-Cycle Model and the Continuous Integrated Fuel-Cycle Model. These models are derived by formally condensing the base equations through spatial integration. Cycle-average isotopic microscopic reaction rate and reactivity-worth coefficients, based on equilibrium behavior, complete the derivation of the discontinuous model. Approximating the discontinuous reload with continuous charge and discharge currents transforms the discontinuous model into the more mathematically elegant continuous model.The results of the continuous model are compared with results obtained from detailed two-dimensional space and multigroup depletion calculations. The continuous model yields nearly the same results as the detailed calculation, and this is with a comparatively insignificant fraction of the computational effort needed for the detailed calculation. Thus, the integrated model presented is an accurate tool for answering questions concerning reactor breeding capability and long-term fuel logistics. 相似文献
34.
Examined the effects of different types of reinforcement on the performance of 80 Black 2nd grade males on the WISC-R. Ss given candy or culturally relevant social reinforcement obtained significantly higher scores than Ss given either no reinforcement or traditional social reinforcement. (2 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
35.
FL Innes 《Canadian Metallurgical Quarterly》1976,69(1):27-30
The effect of red (660 nm) and far-red (730 nm) light on the stability of the yeast Candida guilliermondii to lethal u.v. radiation has been studied. Reactivation and protection were exhibited for 30 min after treatment with red light and were abolished by far-red exposure applied within this time period. The temperature dependence of the reactivation effect was also studied. The data obtained showed that the properties of recovery and protection against u.v. exposure are associated with the phytochrome system of the yeast. 相似文献
36.
37.
Characteristics of a human cell line transformed by DNA from human adenovirus type 5 总被引:18,自引:0,他引:18
One hundred and fifty lungs from the cases below 15 years of age with various congenital heart diseases and 80 controls were used for histometrical and histological studies. Cases with congenital heart disease were divided into two groups of the increased and the decreased pulmonary blood flow. In the former group, the thickness of the pulmonary arterial media was the same as that of controls in the neonatal period, and through the wall thickness gradually decreased in a pattern seen in controls, the thickness was constantly larger than that of controls. In some cases, the media increased gradually within 6 months after birth. Pneumonia and massive pulmonary hemorrhage were seen in a higher incidence in autopsy cases. Pneumonia in younger infants was histologically characteristic and possibly more correlated to their death. In the latter group, most of the cases were with the thinner medias of the pulmonary arteries. Massive pulmonary hemorrhage was not common in the latter group. 相似文献
38.
39.
Pushkar Tandon James P. Terrell Xiaodong Fu Amy Rovelstad 《International Journal of Heat and Mass Transfer》2003,46(17):3201-3209
A method is presented to predict the soot volume fraction in soot-laden gas streams in systems where thermophoresis is the dominant mechanism of particle deposition onto adjoining surfaces. In particular, we considered deposition of silica particles on a circular cylinder in cross-flow to a premix CH4/O2 flame, a setup similar to the one used in the outside vapor deposition process used for making optical fibers. Silica particles were produced by introducing SiCl4 along with the premix gases to the burner and were collected on a cylinder. Heat flux and mass deposition rate measurements on the cylinder were performed and recorded as a function of time. Considering thermophoresis to be the dominant mechanism of particle deposition, a simple theory was developed to establish the relationship between the measured quantities. The theory predicted that the thickness at any given time t was expected to increase linearly with the integral of (integrated from t=0 to t=t), where q′′(t) is the heat flux. Such a linear relationship was observed for five different reactant flow rates confirming thermophoresis to be the dominant mechanism of particle deposition. Soot volume fraction and soot mass fraction were calculated from the slope of these linear fits and were seen to be in good agreement with the estimates of the soot fraction from light scattering measurements. Based on the light scattering estimates of particle diameter, particle number densities were also estimated. 相似文献
40.
Familial adenomatous polyposis (FAP) is an autosomal dominant disease characterized by the development of numerous adenomatous polyps in the colon and rectum with diverse extracolonic manifestations. Recent genetic advances have lead to the sequencing of the FAP gene, with important implications for screening, diagnosis and follow-up. Appropriate management of probands and at-risk patients is of the utmost importance, as untreated carriers will develop colorectal cancer. Identification of FAP families and tracing of pedigrees represent the most important steps. To this end registries are essential, allowing a comprehensive multidisciplinary approach. They have justified their place by decreasing related morbidity and mortality. An overview and discussion of clinical features and management are presented. 相似文献