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991.
1Introduction Since 1980’s ,C1chemistryhashadrapiddevelopmentbasedoncarbonmonoxideascarbonsource .Itispossibletosynthetizemethylformate,dimethylether,ethanoicacid ,methanol,methylcarbonatefromCO[1-2 ] .Yellowphosphorustailgases,withtheirhighCOcontent,couldactasanattractiverawmaterialgasforsynthetizationoftheseandotherproducts.Thereare ,therefore,twobenefits,theavoidanceofenvironmentalpollutionandreductionincostsofyellowphosphorusproduction .However,existingtechniqueshavesomedisadvantages,… 相似文献
992.
气固流化床中气泡分布的实验研究 总被引:1,自引:0,他引:1
用摄像法研究了二维气固流化床的气泡行为,特别是气泡密度的分布规律。开发了针对摄像法研究气泡的数据处理方法,分析比较了布风板、颗粒直径、流化速度、床层高度对气泡分布密度的影响,并与模型计算结果进行了对比,得到气泡分布密度的变化规律。结果表明,气泡分布密度沿床高是不均匀的,存在气泡聚集现象;同一种颗粒在固定床高位置,气泡分布密度随流化速度的变化很小,基本保持稳定。 相似文献
993.
Hydrodynamic behavior of oil-polluted particles of sand was investigated in transparent glass column. The onset of fluidization
of sand beds increased with the oil content of the bed. An increase of cohesive forces related to the higher content of liquid
(oil) caused deterioration of the quality of fluidization. An empirical correlation was developed to predict the dimensionless
gas velocity that keeps the bed of sticky particles fluidized. Results of this work can be employed for the design of fluidized-bed
remediation units for oil-polluted sands and soils.
An erratum to this article is available at . 相似文献
994.
995.
Ammonium molybdophosphate (AMP) immobilized on a polyacrylonitrile (PAN) support is an engineered form of cesium selective sorbent material developed at the Czech Technical University in Prague. This material is being investigated as a sorbent for removing 137Cs from Idaho National Engineering and Environmental Laboratory (INEEL) acidic sodium bearing waste (SBW) solution. As part of this study, a computer program to solve the partial differential equations (PDE's) for continuity and rate of exchange in a fixed bed system has been developed using numerical finite difference algorithms. These equations are solved iteratively in order to derive a mass transfer coefficient that agrees with the results of bench scale column experiments. This mass transfer coefficient is then applied in the PDE solutions to predict breakthrough behavior in a semi-scale column experiment. The model provided excellent agreement with the semi-scale data with a mass transfer coefficient of 0.0126 min–1. 相似文献
996.
T. Kaljuvee M. Toom A. Trikkel R. Kuusik 《Journal of Thermal Analysis and Calorimetry》2007,88(1):51-58
The extensive use of fossil fuels in energy production causes serious
pollution of atmosphere with SO2, CO2,
NOx, etc. In Estonia the electricity production is
based mainly on the pulverized firing (PF) of low-grade local fuel –
Estonian oil shale (EOS) which is characterized by a low calorific value (~9
MJ kg–1) and a high content of mineral matter
(65–70%) from which approximately 50% are carbonates. Since 2004, also
two boilers based on circulating fluidized bed combustion (CFBC) of EOS are
in exploitation.
The present study is focused on the comparative
investigation of the efficiency of different ashes collected from different
technological points of CFB and PF boilers as sorbents for SO2.
The influence of experimental temperature on the SO2-binding
characteristics of ashes as well as the possibilities of activation of ashes
(grinding, hydration) were investigated. It was shown that the SO2-binding
capacity of initial ashes at 700°C and p(SO2)=190
mm Hg was for CFBC ashes 24–30 mg and for PF ashes 10–23 mg SO2
per 100 mg sample, the best binding capacities belonging to economizer ash
(ECOA) and electrostatic precipitator ash from the 1st field (PESPA1f), respectively.
However, during initial stage of binding the best results were obtained with
air pre-heater ash (PHAA) and ESPA1f (both CFBC ashes). Grinding improved
the SO2-binding ability, being the most effective in
the case of bottom ash (BA) from CFBC and cyclone ash (PCA) from PF –
increase in binding capacity 2 and 2.3 times, respectively. As compared to
initial CFBC ashes, the binding characteristics of PF ashes remained lower
even after grinding. Hydration and previous calcination improved the binding
characteristics only of PF ashes. Hereby, the SO2-binding
ability of CFBC ashes is better than of PF ashes and they are more promising
sorbents for acidic gases, for example, for sulphur dioxide. 相似文献
997.
A series of studies have been made on the circulation structure and the responsible mechanisms related to the Cold Water Mass of the Yellow Sea. From the present model governing the nonlinear thermally driven circulation in shallow seas, some complete analytical solutions of temperature and velocity components have been obtained in this paper by solving the coupled equations of motion and heat conduction. The results demonstrate that the wind-induced stirring and the tidal mixing are all responsible for the termal structure formation of Cold Water Mass. The computed vertical convection (u-w) develops only within a thin layer (called "a current shell" here) in the vicinity of thermocline while the deeper layer remains almost motionless. This current structure represents well the maintenance mechanisms of thermocline or the Cold Watermass during the summer. 相似文献
998.
Pseudomonas putida IFO12996 catalyzes the stereoselective hydrolysis of methyl dl ‐β‐acetylthioisobutyramide (dl ‐ATIA) to form d ‐β‐acetylthioisobutyric acid (DAT), a key intermediate for synthesis of a series of angiotensin converting enzyme inhibitors. The esterase gene of Pseudomonas putida IFO12996 was cloned and expressed in Escherichia coli which was further immobilized and retained on a packed bed bioreactor filled with Celite 580. The packed bed bioreactor was used to conduct the stereoselective hydrolysis of dl ‐ATIA and to give DAT with a yield of 34.5%, enantiometric excess value of 97% and enantioselectivity value > 150. The optimal pH and temperature for the reaction were 9.0 and 57 °C ~ 67 °C, respectively. The kinetic constants (Km and Vmax) of immobilized cells were found to be 372.5 mM and 285.7 μmol min?1 (g cell)?1, respectively. The immobilized cells retained over 60% of the initial catalytic activity after 5 batch cycles of production. This paper presents a simple, practical and economical process of immobilization of genetically engineered E. coli on a novel packed bed bioreactor for production of DAT. 相似文献
999.
丙烯氨氧化生产丙烯腈工业流化床反应器的模型化 总被引:1,自引:0,他引:1
在对已有的流化床的流动参数和反应器模型化研究成果的基础上,提出了一个适用于有内构件的丙烯氨氧化制丙烯腈工业流化床反应器两相流动数学模型,在模型中的晕相采用平推流模型,乳浊相采用全混釜串联模型。经过一系列生产数据的检验,证明该模型能够准确描述不同生产负荷下反应器的行为。 相似文献
1000.