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581.
582.
A case of an immunocompetent 60 year old patient is reported, who suffered extensive thoracic spinal injury and paraplegia after polytrauma. In the course of rehabilitation he developed aspergillus spondylodiscitis in a part of the thoraco-lumbar spine which was primarily uninjured. The diagnostic assessment and therapeutic approach of this rare disorder is elucidated and discussed in the context of paraplegia and polytrauma. Possible mechanisms of inoculation and spreading of the moulds as well as predisposing factors of the disease are discussed in this paper and a review of the recent literature is provided. 相似文献
583.
EE Christensen GW Dietz RC Murry EM Stokely JG Moore 《Canadian Metallurgical Quarterly》1977,12(5):462-464
A partial chest phantom was constructed to compare two commonly employed radiographic techniques, 70 kVp without a grid and 120 kVp with a grid, for the detection of pulmonary nodules. The phantom consisted of human ribs embedded in paraffin, the lungs of a dog injected with silicone rubber, a tissue equivalent wax heart and beeswax nodules. The nodules ranged in size from 3-7 mm. A series of 120 films was exposed, half with each technique, and the films were interpreted by three senior residents and seven staff radiologists. More nodules of all sizes except 3 mm were detected with the 120 kVp technique. The 3 mm nodules were rarely detected with either technique. The disadvantages of the 120 kVp technique were an approximate 50 percent increase in patient exposures and almost twice as many false-positive nodule detections. 相似文献
584.
585.
586.
The electroreduction of difluorodichloromethane, CF2Cl2, has been studied at porous electrodes in LiCl-KCl eutectic. Tetrafluoroethylene is produced in high efficiency at low conversions; the reaction is believed to proceed via difluorocarbene. At high conversions carbon is a major product. In the presence of oxygen, trifluorochloromethane is also formed. Application of fuel cell electrodes to electrosynthesis of gaseous products from gaseous reagents is briefly discussed. 相似文献
587.
This paper presents an evaluation of the effects on road safety of new urban arterial roads in Oslo, Norway, and a synthesis of evidence from similar studies that have evaluated the safety effects of new urban arterial roads in other cities. A before-and-after study was made of four urban arterial road projects in Oslo. The study controlled for general accident trends in Oslo and for regression-to-the-mean. A statistically non-significant reduction of 9% in the number of injury accidents was found for all four projects combined. The effects on safety of new urban arterial roads were found to vary, depending on whether a new arterial road was built, or an existing arterial road upgraded by means of lane additions and reconstruction of junctions to interchanges. New arterial roads tend to induce more traffic, which tends to offset the benefits of a lower accident rate on the new roads. The results for other cities are very consistent with those for Oslo. For a total of seven cases in which new arterial roads were built, a statistically non-significant reduction of 1% in the number of injury accidents was found. Two cases that involved lane additions and converting at-grade junctions to interchanges resulted in a mean accident reduction of 51%, which was highly significant. On the average, the nine arterial road projects from which evidence was summarised resulted in a net induced traffic of 16%, and a net reduction in accident rate (accidents per million vehicle kilometres) of 18%. These effects almost cancel each other, leading to a very small net change in the expected number of accidents. 相似文献
588.
Youravong N Chongsuvivatwong V Teanpaisan R Geater AF Dietz W Dahlén G Norén JG 《The Science of the total environment》2005,348(1-3):73-81
Lead is one of the major environmental pollutants and a health risk. Dental hard tissues have a capacity to accumulate lead from the environment. Eighty exfoliated primary teeth were collected from children residing around a shipyard area in southern Thailand, known for its lead contamination. The morphology of the enamel was examined by polarized light microscopy (PLM), microradiography (MRG), and scanning electron microscopy (SEM). The specimens derived from two groups of children, one group with high blood levels of lead (57 teeth) and one group having low blood levels of lead (23 teeth). The enamel irrespective of group appeared normal. However, in a majority of the specimens the enamel surface appeared hypomineralized, which was confirmed in SEM. No morphological changes connected to lead in blood could be found. The hypomineralized surface zone could possibly be attributed to an acid oral environment. 相似文献
589.
Dipl.-Ing. Ulrich Dietz Dr.-Ing. Erich Prochnio Dr.-Ing. Martin Ruppert 《Forschung im Ingenieurwesen》1987,53(5):156-158
Zusammenfassung In diesem Aufsatz wird ein stochastisches Optimierungsverfahren vorgestellt, das die L?sung beliebiger Optimierungsprobleme
ohne Kenntnis des Gradienten der Gütefunktion erlaubt. Das Verfahren ist eine Weiterentwicklung der mehrgliedrigen Evolutionsstrategie
dahingehend, da? die implizit in der Objektmenge enthaltene Gradienteninformation ausgenutzt wird. Anhand von Testrechnungen
wird nachgewiesen, da? die Konvergenzsicherheit sehr hoch ist. 相似文献
590.
Elvik R 《Accident; analysis and prevention》2003,35(4):557-570
This paper analyses how setting priorities for road safety strictly according to cost-benefit analysis would affect the provision of road safety in Norway and Sweden. The paper is based on recent analyses of the efficiency of road safety policies in these two countries. The argument sometimes made by critics of cost-benefit analysis, that only a few road safety measures are cost-effective (have benefits greater than costs), is not supported. Cost-effective road safety policies could prevent between 50 and 60% of the current number of road accident fatalities in both Norway and Sweden, if pursued consistently during a period of 10 years (2002-2011). If current policies are continued, only about 10-15% of the current number of road accident fatalities are likely to be prevented during the next 10 years. A number of sources of inefficiency in road safety policy are identified. A source of inefficiency is anything that prevents policy priorities from being set according to cost-benefit analysis. These include: (a) lack of power, which means that national governments do not have the formal authority to introduce a certain road safety measure, in Europe, this applies to new vehicle safety standards, which are passed almost exclusively by the European Union; (b) the existence of social dilemmas, which means that measures that are cost-effective from a societal point of view are not so from the point of view of individual road users; (c) priority given to other policy objectives, in particular regional development. Scarcity of resources, which obtains when public budgets have to be increased to make room for all cost-effective measures, was not found to be a constraint. All cost-effective measures can be funded within current budgets, provided the use of inefficient measures ceases. 相似文献