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991.
992.
The esterification of the hydroxyl group of starch with DuPont Surlyn was considered as pretreatment method of starch before blending with polyolefins. In treating starch with Surlyn, two different raction conditions were taken to optimize reaction conditions. First, the esterification reaction was carried out in 110°C xylene with oleic acid as a catalyst. Second, the reaction out in a 90°C mixture of deionized water and xylene with ceric ammonium nitrate(CAN) as an initiator. Starch granules would be swollen above the gelatinization temperature in water. In both cases starch was midified by Surlyn to have good compatibility with low-density polyethylene (LDPE). The mechanical and theological properties were examined for blends of the treated starch and LDPE. This system may be one of the biodegradable polymer blends that sufficiently retain properties as a packaging film. 相似文献
993.
994.
This study investigates the effects of cement type, curing temperature, and age on the relationships between dynamic and static elastic moduli or compressive strength. Based on the investigation, new relationship equations are proposed. The impact-echo method is used to measure the resonant frequency of specimens from which the dynamic elastic modulus is calculated. Types I and V cement concrete specimens with water-cement ratios of 0.40 and 0.50 are cured isothermally at 10, 23, and 50 °C and tested at 1, 3, 7, and 28 days.Cement type and age do not have a significant influence on the relationship between dynamic and static elastic moduli, but the ratio of static to dynamic elastic modulus approaches 1 as temperature increases. The initial chord elastic modulus, which is measured at low strain level, is similar to the dynamic elastic modulus. The relationship between dynamic elastic modulus and compressive strength has the same tendency as the relationship between dynamic and static elastic moduli for various cement types, temperatures, and ages. 相似文献
995.
Measurements of non-methane hydrocarbons (NMHC) were performed at the entrance and exit of the Sangdo tunnel to estimate emission
factors (EF) of NMHC from vehicles in May 2000. About 50 species were analyzed by a combined GC/FID and GC/MS system. Ethylene
was the most abundant compound, followed by n-butane and acetylene, respectively. Based on the measurement data, the real
world vehicular EF in Seoul was estimated. The highest EF value was 89.8 mg (veh-mile)-1 for n-butane, followed by ethylene and toluene. 相似文献
996.
微乳液法制备包裹型锆铁红陶瓷颜料 总被引:3,自引:0,他引:3
利用辛基苯基聚氧乙烯醚(triton X-100)/正己醇/环己烷所形成的水/油型微乳液首先获得了Fe-ZrSiO4红色陶瓷颜料的前驱体,经煅烧后合成了包裹型的锆铁红陶瓷颜料.通过热重-差热分析、X射线衍射、透射电子显微镜、能谱分析及色度测试等对颜料的形成过程、微观结构及性能进行了表征和分析.结果表明:微乳液法所制备锆铁红颜料前驱体为无定形粉末,且残留有一定量的表面活性剂等有机物:该前驱体在600℃以下会发生约45%的质量损失,600℃以上质量几乎不再发生改变.无矿化剂作用下,锆铁红陶瓷颜料的开始形成温度约为1 100℃;前驱体在1 200℃煅烧并保温1 h可获得包裹型锆铁红陶瓷颜料,该颜料红度值较高(a*=28.95),且具有较高的包裹率. 相似文献
997.
998.
A semi-empirical equation of state for the freely jointed square-well chain fluid is developed. This equation of state is
based on Wertheim’s thermodynamic perturbation theory (TPT) and the statistical associating fluid theory (SAFT). The compressibility
factor and radial distribution function of square-well monomer are obtained from Monte Carlo simulations. These results are
correlated using density expansion. In developing the equation of state the exact analytical expressions are adopted for the
second and third virial coefficients for the compressibility factor and the first two terms of the radial distribution function,
while the higher order coefficients are determined from regression using the simulation data. In the limit of infinite temperature,
the present equation of state and the expression for the radial distribution function are represented by the Carnahan-Starling
equation of state. This semi-empirical equation of state gives at least comparable accuracy with other empirical equation
of state for the square-well monomer fluid. With the new SAFT equation of state from the accurate expressions for the monomer
reference and covalent terms, we compare the prediction of the equation of state to the simulation results for the compressibility
factor and radial distribution function of the square-well monomer and chain fluids. The predicted compressibility factors
for square well chains are found to be in a good agreement with simulation data. The high accuracy of the present equation
of state is ascribed to the fact that rigorous simulation results for the reference fluid are used, especially at low temperatures
and low densities.
This paper was presented at the 8th APCChE (Asia Pacific Confederation of Chemical Engineering) Congress held at Seoul between
August 16 and 19, 1999. 相似文献
999.
以对醛基苯甲酸为原料,通过醛酸与2,3-二甲基-2,3-二羟胺基丁烷缩合,再经NaIO4氧化最终制得4-(4,4,5,5-四甲基-1,3-二氧化物)咪唑基-1-苯甲酸(NIT-Ph-p-BEN氮氧自由基)。采用FTIR、UV、ERP(电子顺磁共振波谱仪)和元素分析等对其结构进行表征;通过催化降解废水中有机染料甲基橙、甲基蓝和罗丹明B对其催化活性进行了评估。结果表明,当甲基橙、甲基蓝和罗丹明B浓度为15 mg/L,NIT-Ph-p-BEN质量浓度为0.15 g/L,H2O2浓度为30 mmol/L时,NIT-Ph-p-BEN对甲基橙有更好的催化降解性,仅在1 h内甲基橙的降解率达到94.26%。此外,反应机理表明,H2O2有助于实现NIT-Ph-p-BEN自由基的再生和循环利用。 相似文献
1000.
在空气中杀菌灯产生臭氧及其催化分解的研究 总被引:5,自引:0,他引:5
用流动型反应装置,对8W杀菌灯(主波长λ=253.7nm)辐照空气时产生的臭氧进行了研究.发现在一定条件下当空气与杀菌灯接触大约7s时,就有超出0.33μg/L的臭氧产生.随着空气流速的减小,产生的臭氧的量随之变大.采用臭氧分解催化剂对臭氧的消除进行了研究,当体积空速小于1.1×105h-1时,臭氧可以降解到安全范围. 相似文献