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Chua Hong Li Xiang Z. Yu Peter H. F. Tam Chung Y. Huang Yu L. Yang Shang T. 《Applied biochemistry and biotechnology》2000,84(1-9):469-478
Biological processes have become popular for odor treatment. In this study, a novel fibrous bed bioreactor was applied for
treatment of odorous gas. The column reactor was packed with spirally wound fibrous sheet material on which a consortium of
microorganisms selected from activated sludge was immobilized. The first stage of this work comprised a preliminary study
that aimed at investigating the feasibility of the fibrous bed bioreactor for treatment of odorous volatile fatty acids (VFAs).
In this stage, the performance of a fibrous bed bioreactor at increasing mass loadings ranging from 9.7 to 104.2 g/(m3·h) was studied. VFA removal efficiencies above 90% were achieved at mass loadings up to 50.3 g/(m3·h). At a mass loading of 104.2 g/(m3·h), removal efficiency was found to be 87.7%. In the second stage of the work, the process was scaled up with design and
operational considerations, namely, packing medium, process condition, and configuration selections. A trickling biofilter
with synthetic fibrous packing medium was selected. It was operated under countercurrent flow of gas and liquid streams. The
effects of inlet concentration and empty bed retention time on bioreactor performance were studied. The bioreactor was effective
in treating odorous VFAs at mass loadings up to 32g/(m3·h), at which VFAs started to accumulate in the recirculation liquid, indicating that the biofilm was unable to degradeall
the VFAs introduced. Although VFAs accumulated in the liquid phase, the removal efficency remained above 99%, implying that
the biochemical reaction rate, rather than gas-to-liquid mass transfer rate, was the limiting factor of this process. The
bioreactor was stable for longterm operation; no clogging and degeneration of the packing medium was observed during the 4-mo
operation. 相似文献
914.
Josmar Davilson Pagliuso Geraldo Lombardi Leonardo GoldsteinJr. 《Experimental Thermal and Fluid Science》2000,20(3-4)
The role of particle diameter in the heat transfer of a gas–solid suspension to the walls of a circulating fluidized bed was studied for particles of uniform size. This work reports and analyzes new experimental results for the local bed to wall heat transfer coefficient, not including the radiation component, in a long active heat transfer surface length laboratory bed, which extend previous findings and clear up some divergences. The research included determining the effects of extension and location of the heat transfer surface, circulating solids mass flux and average suspension density. An experimental set-up was built, with a 72.5 mm internal diameter riser, 6.0 m high, composed of six double pipe heat exchangers, 0.93 m high, located one above the other. Five narrow sized diameter quartz sand particles − 179, 230, 385, 460 and 545 μm − were tested. Temperature was kept approximately constant at 423 K and the superficial gas velocity at 10.5 m/s. The major influence of suspension density on the wall heat transfer was confirmed, and contrary to other authors, a significant effect of particle size was found, which becomes more relevant for smaller particles and increasing suspension density. It was observed that the extension of the heat transfer surface area did not influence the heat transfer coefficient for lengths greater than 0.93 m.The heat transfer surface location did not show any effect, except for the exchanger at the botton of the riser. A simple correlation was proposed to calculate the heat transfer coefficient as a function of particle diameter and suspension density. 相似文献
915.
基于推移质输沙率与水流动力条件之间的关系,提出了一种计算年平均推移质输沙量时,代表性水流动力条件的选择方法,同时将断面分为若干子断面进行计算,可以解决推移质沿断面不均匀输移的计算困难,计算过程中还考虑了推移4质级配的逐时变化。所提出的计算方法应用于黄河青铜峡水库,计算了年平均推移质量,结果与实测淤积量符合很好。 相似文献
916.
气—固流化床反应器内双流体力学模型及其验证:Ⅳ.单组分两维射流床内气泡特性 总被引:1,自引:0,他引:1
模拟了不同操作条件下,单组分两维射流床内射流崩塌后所形成气泡的形状、运动机理、初始尺寸和上升速度。集合前文(Ⅰ、Ⅱ和Ⅲ)研究结果表明,在湍流两相流理论基础上建立的“气-固流化床反应器内双流体力学模型”可以很好地分析气固射流床内流体动力学特性,诸如:基本流场变量(气、固相速度场、压力场和空隙率)瞬态变化情况、射流特性(射流发展、射流穿透深度确定方法、射流区气体速度分布和操作条件对射流穿透深度、射流频率的影响等)、时均空隙率分布、时均轴向气体速度分布和气泡特性。由此可见,该方法和思路可以为灰熔聚流化床粉煤气化工艺和其他与流态化技术相关的设计提供必要的信息和有益的建议 相似文献
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