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991.
碳纤维的高温氧化动力学模型 总被引:1,自引:0,他引:1
唐龙贵 《高等学校化学学报》1995,16(11):1823-1825
碳纤维的高温氧化动力学模型唐龙贵(浙江大学高分子科学与工程研究所,杭州,310027)关键词碳纤维,氧化,动力学,模型碳纤维是一种具有高比强度、高比模量、耐磨、导电等优良性能的骨架材料,是制造高性能复合材料的基础。它在宇航、军事等高技术工业领域得到了... 相似文献
992.
993.
碳纤维的抗氧化处理 总被引:3,自引:1,他引:2
唐龙贵 《高等学校化学学报》1995,16(8):1301-1305
用硼化合物对碳纤维进行抗氧化处理,提高了纤维的高温抗氧化性能。用热分析、电子显显微镜、表面电子能谱和X射线衍射等进行了研究,结果表明:碳纤维经过硼化合物处理后,氧化活化能提高123.4%,热氧化分解点提高268℃,高温使用寿命提高许多倍,但物理机械性能变化不大。 相似文献
994.
Wenjun Lu Yoshinori Yamaoka Yuki Taniguchi Tsugio Kitamura Ken Takaki Yuzo Fujiwara 《Journal of organometallic chemistry》1999,580(2):10442
Aromatic compounds such as benzene, toluene, chlorobenzene, anisole, and naphthalene were carboxylated by palladium(II) acetate catalyst with carbon monoxide in the presence of potassium peroxodisulfate in trifluoroacetic acid (TFA) at room temperature under atmospheric pressure. The aromatic carboxylic acids were formed in good yields; for example, the carboxylation of benzene with carbon monoxide proceeds quantitatively under the optimal conditions. 相似文献
995.
996.
Four Fe—CO states with 3dσ-4s, 3dδ-3dδ electrons spin-paired or spinunpaired were examined to investigate the influences of pairing versus unpairing mechanisms upon the bonding, interaction in Fe—CO. The calculation results show that the Fe—CO bonding, interaction are determined by a balance between the bonding stabilization, the exchange stabilization with 3dσ-4s electron spinpairing or without it. The 3dδ-3dδ electron spinpairing versus unpairing has a surprised effect on the Fe—CO bonding properties even though the 3dδ orbitals are usually considered as non bonding ones. 相似文献
997.
Hydrogen removal from C-doped InGaAs grown on InP substrate by metalorganic chemical vapor deposition is discussed based on the dependence of hole concentration on various annealing conditions. It is revealed that the hydrogen removal rate becomes higher as the annealing temperature is higher and the activation energy of hydrogen removal is about 1.9 eV regardless of C-doped layer thickness. The hydrogen removal rate is also found to be inversely proportional to C-doped layer thickness, suggesting that the hydrogen removal reaction is mainly governed by hydrogen diffusion. 相似文献
998.
Summary Catalytic fractional conversions of carbon monoxide to carbon dioxide over Pt−Rh alloy catalysts in the presence of excess
oxygen, under steady-state or non steady-state conditions, as well as corresponding rate constants for the CO oxidation reaction
were measured by using the reversed-flow gas chromatographic technique. From the variation of the conversions with temperature,
maximum values of conversions were found, which depend on the catalysts nature (Pt content), while from the variation of the
rate constants with temperature, activation energies for the CO oxidation reaction were determined, which also depend on the
catalyst Pt content. The results suggest a synergism between Pt and Rh in the Pt−Rh bimetallic catalysts in accordance with
previous works, showing that reversed-flow gas chromatography can be used with simplicity and accuracy for the kinetic study
of the CO oxidation reaction, which is of technological importance for the control of air pollution. 相似文献
999.
A mathematical model describing the dynamic emission of a single mode TE CO2 laser with saturable absorber has been adapted. A six-temperature model has been used to describe the amplifying medium, while a four-coupled energy level is used to describe the selective absorbing medium. The suggested mathematical model allows the investigation of the effects of the intracavity absorber on the mode characteristics of the TE CO2 laser and, moreover, the study of the effect of the laser input parameters on the output laser pulse. The model simulates the passive Q-switch in both low- and high-pressure cases in the absorbing medium.
In addition, numerical solutions of a non-linear rate equation system of the suggested model are quantitatively discussed. The solutions describe the photon number density, the population inversion and the energy transfer processes of amplifying and absorbing media. 相似文献
1000.
在C/KOH/Ni(OH)2型非对称电化学电容体系中,Ni(OH)2电极需具有快速发生电化学反应的能力与活性炭负极匹配。本文通过增加微集流体的掺杂比例.对活性物质进行球磨处理、固相掺杂碳纳米管等方法对正极进行改性研究。实验发现,增加正极微集流体的掺杂比例.可明显改善非对称电容大电流条件下的容量和循环性能;对正极活性物质进行球磨处理,有利于电极活性物质的转变.加快非对称电容的活化速度;在正极固相掺杂一定比例的碳纳米管可提高非对称电容的充放电效率和容量性质。 相似文献