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排序方式: 共有192条查询结果,搜索用时 218 毫秒
1.
Chemistry is a central science. However, the public's recognition of chemistry needs to be promoted, and the prejudice needs to be reduced. Chemical science popularization is a long-term, complex and arduous social education project, which is of great significance to promote social harmony and improve people's quality of life. This paper summarizes the current status of chemical science popularization in China, and puts forward the innovative development countermeasures which focus on improving public participation, training popular science talents, carrying out popular science popularization education at different levels, creating high-quality science popularization works and opening up new positions and approaches of chemical science popularization. This paper has the reference value for the science popularization colleagues. 相似文献
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The influence of CCl4 on the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), the value of the
total antioxidant status (TAS), and the concentration of malonic dialdehyde (MDA) and glutathione (GSH) was monitored in plasma
or whole blood of rabbits. The administration of CCl4 caused the increase of the SOD activity to approximately 150 % and the decrease in the activity of GPx and GR by about 50
%. These changes were accompanied with the increase in TAS value and MDA concentration and the decrease of GSH concentration.
The effect of CCl4 was suppressed by the previous 7 days lasting or simultaneous administration of vitamin E. Oxidative stress caused by CCl4 was accompanied by the development of reactive oxygen forms, especially superoxide radical anion. 相似文献
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Mohammad A. Alzohairy Amjad Ali Khan Mohammed A. Alsahli Saleh A. Almatroodi Arshad Husain Rahmani 《Molecules (Basel, Switzerland)》2021,26(11)
Benzopyrene [B(a)P] is a well-recognized environmental carcinogen, which promotes oxidative stress, inflammation, and other metabolic complications. In the current study, the therapeutic effects of thymoquinone (TQ) against B(a)P-induced lung injury in experimental rats were examined. B(a)P used at 50 mg/kg b.w. induced lung injury that was investigated via the evaluation of lipid profile, inflammatory markers, nitric oxide (NO), and malondialdehyde (MDA) levels. B(a)P also led to a decrease in superoxide dismutase (SOD) (34.3 vs. 58.5 U/mg protein), glutathione peroxidase (GPx) (42.4 vs. 72.8 U/mg protein), catalase (CAT) (21.2 vs. 30.5 U/mg protein), and total antioxidant capacity compared to normal animals. Treatment with TQ, used at 50 mg/kg b.w., led to a significant reduction in triglycerides (TG) (196.2 vs. 233.7 mg/dL), total cholesterol (TC) (107.2 vs. 129.3 mg/dL), and inflammatory markers and increased the antioxidant enzyme level in comparison with the group that was administered B(a)P only (p < 0.05). B(a)P administration led to the thickening of lung epithelium, increased inflammatory cell infiltration, damaged lung tissue architecture, and led to accumulation of collagen fibres as studied through haematoxylin and eosin (H&E), Sirius red, and Masson’s trichrome staining. Moreover, the recognition of apoptotic nuclei and expression pattern of NF-κB were evaluated through the TUNEL assay and immunohistochemistry, respectively. The histopathological changes were found to be considerably low in the TQ-treated animal group. The TUNEL-positive cells increased significantly in the B(a)P-induced group, whereas the TQ-treated group showed a decreased apoptosis rate. Significantly high cytoplasmic expression of NF-κB in the B(a)P-induced group was seen, and this expression was prominently reduced in the TQ-treated group. Our results suggest that TQ can be used in the protection against benzopyrene-caused lung injury. 相似文献
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This paper presents an analysis of the combining mechanism for status information postulated by the mathematical formulation of the theory of status characteristics and expectation states. Six lemmas on the basic features of the combining mechanism are derived from the formulation and discussed. Further, four theorems that illustrate the implications of the particular combining mechanism for power and prestige orders are presented and proven. 相似文献
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Fluorogenic Probes Applied to the Study of Induced Oxidative Stress in the Human Leukemic HL60 Cell Line 总被引:1,自引:0,他引:1
E. Plantin-Carrenard F. Braut-Boucher M. Bernard C. Derappe M. J. Foglietti M. Aubery 《Journal of fluorescence》2000,10(2):167-167
Development of microspectrofluorometric methods using specific fluorogenic probes has provided precious help in studying in situ oxidative stress and cellular protective systems. The aim of this study was to determine ROS production concomitantly with a modification of the intracellular thiol pool after applying an oxidative stress to a nonadherent cell model represented by the HL60 cell line. The dichlorodihydrofluorescein diacetate (H2DCFDA) probe assessed the kinetic production of ROS by cells submitted to the chemical oxidant t-butylhydroperoxide with a high signal/noise ratio. The probe sensitivity permitted us to detect endogenous ROS production in HL60 cells and the protective effect of N-acetyl cysteine against ROS. The chloromethylfluorescein diacetate probe (CMFDA) permitted us to evaluate the thiol depleting effect of N-ethyl maleimide. Complete thiol depletion was associated with a moderate increase in ROS production. The cell viability was determined with calcein-AM, which gave results similar to those with the tetrazolium dye. This probe was not affected by intracellular pH and did not required an extraction step, unlike tetrazolium dye. In conclusion, cell-permeant fluorogenic probes are useful and sensitive tools to determine in situ ROS production concomitantly with consecutive change in the thiol system in a living and non-adherent cell model. 相似文献
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Hyuk-Sung Kwon 《Insurance: Mathematics and Economics》2008,43(3):394-402
Mortality rates are known to depend on socio-economic and behavioral risk factors, and actuarial calculations for life insurance policies usually reflect this. It is typically assumed, however, that these risk factors are observed only at policy issue, and the impact of changes that occur later is not considered. In this paper, we present a discrete-time, multi-state model for risk factor changes and mortality. It allows one to more accurately describe mortality dynamics and quantify variability in mortality. This model is extended to reflect health status and then used to analyze the impact of selective lapsation of life insurance policies and to predict mortality under reentry term insurance. 相似文献