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81.
本文给出了复合地基应力比置换率设计的优化方法,讨论了复合地基中应力比的基本概念和影响因素,可供工程应用时参考。 相似文献
82.
Wang Xing-kui Li Dan-xun Qu Zhao-song Wang Dian-chang Department of Hydraulic Engineering Tsinghua University Beijing China 《水动力学研究与进展(B辑)》2001,(1)
1 . INTRODUCTIONThebedloadtransporthasbeenextensivelystudiedinthepastfewdecadesandmanyformulasforpredictingbedloadtransportratehavebeenpresented(Einstein 1950 ;Meyer Peter 194 8;Bagnold 1973;Engelund 1976;Yalin 1972 ;Samaga 1986;andKarim 1998) .Whenappliedtostreamswithpartial… 相似文献
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A mathematical model for the drying rate of granular particles in a multistage inclined fluidized bed(IFB) is presented from the standpoint of simultaneous heat and mass transfer, with taking the effect of mechanical vibration added vertically into consideration.
Steady-state distributions for the temperatures and concentrations of the particles and the heating gas, and for the moisture content of the particles are numerically calculated based on the present model. The calculated results show fairly good agreement with the experimental data, which were obtained from the drying experiments of brick particles in a three-stage IFB using comparatively low temperature air(40-60°C) as the heating gas.
It has been found within the range of the experimental conditions employed that, the mechanical vibration added vertically enhances the over-all drying rate of the particles and its effect can be considered equivalent to an increase in the air velocity. 相似文献
Steady-state distributions for the temperatures and concentrations of the particles and the heating gas, and for the moisture content of the particles are numerically calculated based on the present model. The calculated results show fairly good agreement with the experimental data, which were obtained from the drying experiments of brick particles in a three-stage IFB using comparatively low temperature air(40-60°C) as the heating gas.
It has been found within the range of the experimental conditions employed that, the mechanical vibration added vertically enhances the over-all drying rate of the particles and its effect can be considered equivalent to an increase in the air velocity. 相似文献
85.
讨论了固定床反应器阻力降快速升高的原因,介绍了用轴径向技术解决这一问题的原理及优点,及其在铁铬系变换催化剂和钴钼系耐硫变换催化剂反应器中的实际应用。 相似文献
86.
Critical to restoring the nature conservation value of many river corridors is an understanding of how alluvial landscapes will respond to cessation of river management and land use practices that have previously degraded the environment. This paper analyses changes in valley floor landforms and vegetation patch dynamics, in relation to fluvial disturbance, over a period of almost 100 years following flood embankment abandonment on a wandering gravel‐bed river, namely the River Tummel, Scotland. Such rivers were once typical of many draining upland areas of northern maritime Europe. Prior to abandonment the valley floor landscape was agriculturally dominated and the river for the most part was single thread confined between flood embankments. The pattern of landform change and vegetation patch development over time following a decision in 1903 not to maintain embankments was tracked by geomorphic and land cover mapping utilizing successive sets of aerial photography for the period 1946 to 1994. A historical context for these changes was also feasible because the channel planform in 1900 and earlier channel planform changes dating back to 1753 were known due to the availability of old maps and earlier geomorphic studies. The land cover mapping was validated by comparison of results produced from the interpretation work on the 1994 aerial photographs with the field‐based UK National Vegetation Classification protocol. The findings of the study illustrate that bordering the River Tummel fluvial landforms and vegetation patch mosaics, presumably resembling those that occurred before valley floor land use intensification, evolved in less than 50 years after flood embankment abandonment with a resultant increase in habitat diversity. The change relates primarily to flood‐induced channel planform change and moderate levels of fluvial disturbance. The general significance of this change to plant species diversity on the valley floor of the River Tummel and elsewhere is discussed as is possible implications of the upstream impoundment and scenarios for climatically induced changes in flood frequency and magnitude. The overall outcome is the strong possibility that simple changes in river management and land use practices could result in re‐establishment of the nature conservation value of similar river corridors in Europe over the medium term without active restoration efforts. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
87.
分子筛吸附柱和热金属镁床是手套箱气氛中氚化水 (HTO)搜集和分解处理的一种有效手段。测试了分子筛柱对气氛中水的吸附性能和热金属镁床对HTO的分解性能。结果表明 :分子筛柱对气氛中水的吸附效率 >99 99% ,在空气中水含量为 3 4× 1 0 - 3~ 4 2× 1 0 - 3条件下 ,未发现吸附柱水的贯穿现象 ;热金属镁床对HTO的分解率 >99 9% ,当金属镁的消耗量大于 80 %时 ,未见分解率明显降低。 相似文献
88.
89.
滩海油罐CAD/CAG 总被引:1,自引:0,他引:1
根据滩海油田地区环境条件的特殊性,认为取50年一遇的3秒钟瞬时风速作为计算依据更切合实际,给出了相应的抗风设计方法和设计公式,根据最新储油罐抗震理论编制了验算程序.将计算机辅助设计与辅助绘图集成一体,形成了一套完整的储油罐CAD/CAG系统.该系统省去了过去人工计算需要查取数据的麻烦,可以自动检索,并完成各项分析计算和全套施工图的绘制工作.速度快、准确性高,直接输出透明图,整洁规范.该系统正用于实际设计生产. 相似文献
90.