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181.
Polytrimethylpropyne supported on a solid substrate was proposed as a chromatographic adsorbent for the separation of hydrocarbon gases. The heats of adsorption of hydrocarbon gases were determined. The efficiency of application of this sorbent for the selective separation of C1--C4 hydrocarbon gases in packed columns was demonstrated. 相似文献
182.
Time evolution of mass distribution of argon cluster ions has been studied in pulsed jets (pulse duration≈0.4 ms) by retarding potential method. The ejection of cluster ions of the order of 180 atoms from cluster ions of the order of 500 atoms has been revealed. The ejection has a threshold character as a function of the time elapsed after electron impact ionization. The threshold time was about 20 μs. Delayed non-thermal fragmentation of the cluster ions testifies that the self-trapped ion, formed in argon clusters as a result of ionization, can live for a long time in its excited state without dissipation of the excess energy to the cluster. This ion should be located on the surface of the cluster. Energetic analysis of the fragmentation is consistent with the size of the ejected clusters. A model of the observed time evolution of the delayed fragmentation is herein proposed. 相似文献
183.
184.
A. V. Levanov A. R. Gromov E. E. Antipenko V. V. Lunin 《Russian Chemical Bulletin》2000,49(2):380-383
Formic and acetic acids are formed by the low-temperature (77 K) condensation of a mixture of methane and water vapor dissociated
by MW discharge at a low pressure. The effect of experimental conditions on the yield of HCOOH and AcOH was studied under
different experimental conditions. The yields of H, OH, and O2 from MW discharge in the CH4+H2O mixture were determined by ESR in the gas phase under the experimental conditions used to synthesize HCOOH and AcOH. The
kinetics of the gas phase reactions in the connecting channel was simulated. The mechanism of formation of HCOOH and AcOH
through the interaction of active species from the gas phase on the condensate surface was suggested.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 379–382, February, 2000. 相似文献
185.
岩石爆破损伤断裂的细观机理 总被引:31,自引:2,他引:29
基于现有岩石爆破机理和岩石细观损伤力学 ,认为岩石爆破损伤断裂过程包含有爆炸应力波的初期动态损伤演化阶段和后期爆生气体作用下的准静态损伤演化阶段 ,并分别建立了这两个阶段的损伤模型和断裂准则 ,阐述了岩石爆破损伤断裂的细观理论。 相似文献
186.
Dongmin Shen Martin Bülow Flor Siperstein Maximilian Engelhard Alan L. Myers 《Adsorption》2000,6(4):275-286
Experimental measurements of heats of adsorption published in the literature are often in disagreement; differences of 10–20% are common. The three most widely used experimental methods are: (1) differentiation of adsorption isotherms at constant loading; (2) measurement of adsorption isosteres; (3) calorimetry. Results from these methods were compared for the systems nitrogen on CaA, oxygen on CaA, and carbon dioxide on NaX. Although the same materials and similar degassing procedures were used for all experiments, calorimetric heats are about 2 kJ/mol higher than the heats from isoteric measurements. Additional experiments are needed to bring these methods into exact agreement. 相似文献
187.
188.
大气痕量气体差分吸收光谱仪(EM I)是一种紫外可见成像光谱仪,主要用于实现高空间分辨率的全球每日大气痕量气体浓度反演.EM I在轨运行期间,受空间环境影响,元器件性能随时间推移会不断衰变.为有效监测其衰变状况,利用载荷对地各轨0级数据解析出在轨温度,实现长期在轨温度监测;通过计算各轨道星下点黑暗时的暗背景图像噪声的均... 相似文献
189.
A new entropy function s+ is defined in terms of the existing entropy function s° and temperature as s+ = s° − R lnT to facilitate the analysis of isentropic processes of ideal gases with variable specific heats. The function s+ also makes it possible to calculate the entropy changes of ideal gases during processes when volume information is available instead of pressure information and the variation of specific heats with temperature is to be accounted for. The introduction of the function s+ eliminates the need to use the dimensionless isentropic functions relative pressure Pr and relative specific volume vr of ideal gases and to tabulate their values. The Pr and vr data are often confused with pressure and specific volume, with an adverse effect on the study of the second law of thermodynamics. The new s+ function nicely complements the existing s° function in entropy change calculations: the former is conveniently used when volume information is given while the latter is used when pressure information is available. Therefore, the introduction of the new entropy function s+ is expected to make a significant contribution to the thermodynamics education and research by streamlining entropy analysis of ideal gases. 相似文献
190.
Leila Saedi Zahra Javanshir Salah Khanahmadzadeh Maryam Maskanati Milad Nouraliei 《Molecular physics》2020,118(7)
ABSTRACTDensity functional theory calculations were used to investigate the potential application of an AlN nanocluster in the detection of H2S, COS, CS2 and SO2 gases. In overall, the order of strength of interaction of these gases with the nanocluster is as follows: SO2 (Ead?=??17.6?kcal/mol)?>?H2S (Ead?=??14.0?kcal/mol)?>?COS (Ead?=??8.4?kcal/mol)?>?CS2 (Ead?=??4.5?kcal/mol). This indicates that by increasing the electric dipole moment, the adsorption energy becomes more negative. We found that the Al12N12 nanocluster may be a promising work function-type sensor for SO2 gas among the studied gases. Also, it is an electronic sensor for both SO2 and CS2 gases but selectively acts between them because of their different effects on the electrical conductivity. It is neither work function-type nor electronic sensor for H2S and COS gases. The AlN nanocluster benefits from a short recovery time about 7.7?s and 18.0?ms for desorption of SO2 and CS2 gases from its surface at room temperature, respectively. It is also concluded that this cluster can work at a humid environment. 相似文献