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621.
本文就镁锭中杂质元素铜,铁和锰的原子吸收同时测定进行了试验,结果与冶标(YB87-76)分析方法作了对照,均在允许误差范围内。本法的相对标准偏差铜2.8%,铁3.6%,锰3.5%。方法已应用于样品中三个元素的同时测定,节省了大量的人力物力,结果满意。 相似文献
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623.
李萍 《原子与分子物理学报》1994,11(3):255-257
采用Hara free-electron-gas exchange approximation(HFEGE)交换势和本文作者提出的极化势,用等效势模型计算了能量在0.136-12eV内的e-O弹性散射总截面和动量转移截面,结果与Thomas和Nesbet的理论计算结果以及实验结果作了比较。 相似文献
624.
We propose a time-domain interferometry method that circumvents the usual sampling rate condition. It was devised for the retrieval of fast optical response functions in low-repetition-rate experiments. Its potential temporal dynamic range matches the spectral resolution and bandwidth requirements of the arbitrarily shaped spectral filters that are engraved in amorphous spectral hole-burning materials. 相似文献
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626.
F. Gou L.Z.T. Chen C. Meng Q. Qian 《Applied Physics A: Materials Science & Processing》2007,88(2):385-390
Molecular dynamics simulations were performed to investigate F continuously bombarding Si-terminated 3C-SiC(001) surfaces
with incident energies of 10, 100 and 200 eV at normal incidence and room temperature. For an energy of 10 eV, deposition
only occurs on the surface. For energies larger than 10 eV, accompanying the saturation of F uptake, a balance between F deposition
from the incident atoms and F removal from the fluorinated substrate is established, while the steady-state etching is reached.
The simulated results demonstrate that Si atoms in SiC are preferentially etched, which is in good agreement with experiments.
The preferential etching of Si results in formation of a C-rich interfacial layer whose thickness increases with increasing
incident energy. The analysis shows that Si-containing etch products are dominant.
PACS 52.65.Yy; 81.65.Cf; 52.77.Dq 相似文献
627.
Lee KS Lee KY Kim SR Park HS Park SJ Min KH Cho CH Koh GY Park HS Lee YC 《Experimental & molecular medicine》2007,39(6):733-745
Inflammation of the asthmatic airway is usually accompanied by increased vascular permeability and plasma exudation. Angiopoietin-1 (Ang1) has potential therapeutic applications in preventing vascular leakage. Recently, we developed a soluble, stable, and potent Ang1 variant, COMP-Ang1. COMP-Ang1 is more potent than native Ang1 in phosphorylating the tyrosine kinase with immunoglobulin and epidermal growth factor homology domain 2 receptor in lung endothelial cells. We have used a mouse model for allergic airway disease to determine effects of COMP-Ang1 on allergen-induced bronchial inflammation and airway hyper-responsiveness. These mice develop the following typical pathophysiological features of allergic airway disease in the lungs: increased numbers of inflammatory cells of the airways, airway hyper-responsiveness, increased levels of Th2 cell cytokines (IL-4, IL-5, and IL-13), adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1), and chemokines (eotaxin and RANTES), and increased vascular permeability. Intravenous administration of COMP-Ang1 reduced bronchial inflammation and airway hyper-responsiveness. In addition, the increased plasma extravasation in allergic airway disease was significantly reduced by the administration of COMP-Ang1. These results suggest that COMP-Ang1 attenuates airway inflammation and hyper-responsiveness, prevents vascular leakage, and may be used as a therapeutic agent in allergic airway disease. 相似文献
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630.
采用PLASIMO程序模拟了入口处Ar流速对多级弧放电产生的非热平衡Ar等离子体特性的影响。模拟结果发现:从入口处到出口处,沿中心轴线,压强逐渐降低,电子平均能量基本保持不变。当流速一定时,从器壁到中心轴线处,电子数密度呈增大趋势;从入口处到出口处,电子数密度呈先增大后减小的趋势;当流速分别为50,100,150和200 cm3/s时,电子数密度最大值分别为10.131021,16.311021,18.981021和26.331021 m-3;随着流速的增大,其电子数密度逐渐增大。当流速一定时,从器壁到中心轴线处,电子温度逐渐增大;从入口处到出口处,电子温度呈先增大后减小再增大的趋势,并在中心轴线处距入口55~60 mm有最大值,当流速分别为50,100,150和200 cm3/s时,其最大值分别为1.299,1.234,1.157和1.132 eV;由于入口处和器壁处的电子温度都为0.517 eV,所以随着Ar流速的增大,其电子温度逐渐减小。当Ar流速一定时,从器壁到中心轴线处,离子温度逐渐增大;从入口处到出口处,离子温度呈先增大后减小的趋势,并且在中心轴线距入口20~30 mm离子温度取得最大值,当流速分别为50,100,150和200 cm3/s时,离子温度最大值分别为0.815 6,0.907 02,0.975 2和1.014 eV。随入口处流速的增大,电弧腔体内的离子温度逐渐增大。 相似文献