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121.
简要分析各种储氢材料和技术的基础上,重点介绍了高比表面积活性炭的制备方法,目前最常用的活化方法是以氢氧化钾为活化剂的化学活化法;并总结了近年来前人在高比表面积活性炭储氢方面的研究结果,同时简要分析了高比表面积活性炭储氢机理方面的研究进展. 相似文献
122.
Luiz Pereira Ramos Helena Maria Wilhelm 《Applied biochemistry and biotechnology》2005,123(1-3):807-819
In recent years, the concept of producing biodiesel from renewable lipid sources has regained international attention. In
Brazil, a national program was launched in 2002 to evaluate the technical, economic, and environmental competitiveness of
biodiesel in relation to the commercially available diesel oil. Several research projects were initiated nationwide to investigate
and/or optimize biodiesel production from renewable lipid sources and ethanol derived from sugarcane (ethyl esters). Once
implemented, this program will not only decrease our dependence on petroleum derivatives but also create new market opportunities
for agribusiness, opening new jobs in the countryside, improving the sustainability of our energy matrix, and helping the
Brazilian government to support important actions against poverty. This article discusses the efforts to develop the Brazilian
biodiesel program in the context of technical specifications as well as potential oilseed sources. 相似文献
123.
A. V. Evtushenko M. S. Molchanova B. B. Smirnov V. A. Shlyapochnikov 《Russian Chemical Bulletin》1996,45(10):2302-2308
Computer design was concocted for a series of caged alicyclic structures without small cycles. With the help of molecular-mechanical calculations, the enthalpies of formation and the strain energies were determined for the corresponding compounds. The possibility of tile existence of highly strained frameworks without small cycles was analyzed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2430–2437, October, 1996. 相似文献
124.
HPLC法测定鸡精中谷氨酸钠的含量 总被引:3,自引:0,他引:3
以邻苯二甲醛与谷氨酸钠中的氨基进行柱前在线衍生化反应,采用C18色谱柱分离、荧光检测器(激发340nm,发射450nm)进行测定,建立了柱前衍生反相高效液相色谱测定鸡精中谷氨酸钠含量的方法。该方法相对标准偏差为0.69%,加标回收率为99.1%~101%,在0.10~50.0mg/L范围内,谷氨酸钠的峰面积和浓度之间的相关系数为0.9999,保留时间和峰面积的相对标准偏差分别为1.22%和0.71%,鸡精中谷氨酸钠定量下限为0.2μg/g。 相似文献
125.
本文用水作为分散介质,掺杂一定量的ZnO于Bi_4Ti_3O_(12)中,采用高能球磨法制备了异质结型光催化剂ZnO/Bi_4Ti_3O_(12).利用UV-Vis、XRD、SEM和PL等仪器对样品进行了分析与表征.以375 W中压汞灯为光源,通过对亚甲基蓝的氧化来研究其光催化活性.结果表明,对于光氧化亚甲基蓝(MB),异质结型光催化剂ZnO/Bi_4Ti_3O_(12)光催化活性高于钛酸铋的光催化活性.当ZnO的掺杂量分别是0.0和0.5wt.%,异质结型光催化剂ZnO/Bi_4Ti_3O_(12)对亚甲基蓝光氧化率分别达到50.2和80.3 %. 相似文献
126.
建立了胶粘剂中游离甲醛的高效液相色谱检测方法,对提取方法、衍生化条件及色谱条件进行了研究。结果表明,采用超声波萃取法代替经典的水蒸气蒸馏法能更快速、高效地提取目标物。液相色谱法对甲醛的检出限为0.024μg/mL,在0.1~12μg/mL范围内,线性相关系数R^2=0.9995,在1、2、8μg/mL三个添加水平下,回收率在98.73%~101.68%之间。五个实验室间的相对标准偏差为2.6%。对某白乳胶样品的测定结果表明,本法在定性检测、抗干扰能力及稳定性上都高于常用的乙酰丙酮比色法。 相似文献
127.
128.
H. J. Lewerenz K. Skorupska M. Aggour T. Stempel J. Grzanna 《Journal of Solid State Electrochemistry》2009,13(2):185-194
Photoelectrochemically prepared nanotopographies on semiconductors are used for realization of nanoemitter solar devices that
are active in the photovoltaic and the photoelectrocatalytic mode. The development of solar devices by a nonlinear electrochemical
process and combined chemical/electrochemical metal deposition is described. Based on this low-temperature scalable approach,
first efficiencies of 7.3% in the photovoltaic mode are reported for the photoelectrochemical solar cell n-Si/SiO2/Pt/I3
−–I−. With p-Si/Pt nanocomposite structures, light-induced H2 evolution is achieved. The surface chemistry and morphology is analyzed by photoelectron spectroscopy (PES), Fourier transform
infrared spectroscopy, and high-resolution scanning electron microscopy. The operational principle of Pt-based nanoemitter
solar devices that use silicon single crystal absorbers is analyzed by Mott–Schottky plots, chronoamperometric profiles, and
PES. Related to simultaneous oxide formation during Pt deposition, evidence for the formation of a metal–oxide–semiconductor
junction is obtained that explains the observed electronic behavior.
Contribution to the Fall Meeting of the European Materials Research Society, Symposium D: 9th International Symposium on Electrochemical/Chemical
Reactivity of Metastable Materials, Warsaw, 17th–21st September 2007. 相似文献
129.
Two glasses, the first one with the composition of Li2O·2SiO2 and the second one with the addition of CaO, P2O5 and CaF2 in the stoichiometric ratio corresponding to fluoroapatite were prepared and their tendency to crystallize has been studied
by non-isothermal DTA analysis. The values of kinetic parameters calculated using the isoconversional integral method have
been used to determine the temperature dependencies of both the length of isothermal induction period and the length of overall
isothermal crystallization for both glasses. The estimated dependencies indicate that the glass containing CaO, P2O5 and CaF2 has a lower thermal stability. 相似文献
130.
First-principle pseudopotential plane wave calculations and the Nudged Elastic Band method based on density functional theory (DFT) have been used in this article to study the dissociation of molecular hydrogen on a Mg(0001) surface and the subsequent diffusion of atomic hydrogen into the magnesium substrate. First, the dissociation pathway of H2 and the relative barrier were investigated. It was shown that physical adsorption rather than chemisorption of molecular hydrogen was observed in the calculation of the dissociation process of molecular hydrogen. Also, the diffusion process of atomic hydrogen on Mg(0001) was presented. The surface effect, which affected the diffusion of hydrogen obviously, was observed. Finally, comparing the values of the activation energies for the steps of dissociation, diffusion, and desorption, our calculation further showed that the dissociation of H2 and the desorption of hydride were the rate-limiting steps. 相似文献