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1.
The aim of the present study was to examine the effect of quercetin-rich onion peel extract (OPE) on anti-differentiation in 3T3-L1 preadipocytes and the antiobesity in high-fat fed rats. We found that lipid accumulations and TG contents in 3T3-L1 cells were markedly suppressed by OPE. The mRNA levels of activating protein (AP2) were down-regulated and those of carnitine palmitoyl transferase-1 α (CPT-1α) and fatty acid binding protein 4 (FABP4) were up-regulated by 75 and 100 μg/ml OPE. Body weight, retroperitoneal and mesenteric fat weights of SD rats were significantly lower in the 8 week high fat (HF) diet + 0.72% OPE group than in the HF group. Peroxisome proliferator-activated receptor (PPAR)γ mRNA levels were down-regulated in the epididymal fat of OPE than those of control and HF, and significant down-regulation of CCAAT/enhancer binding protein (C/EBP)α mRNA levels in OPE was also observed than the control. The mRNA levels of CPT-1α and uncoupling protein-1 (UCP-1) were up-regulated by the OPE, while those of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) were down-regulated in HF and OPE groups compared to control group. These results suggest that quercentin-enriched OPE may have antiobesity effects by suppressing preadipocyte differentiation and inhibiting adipogenesis.  相似文献   
2.
Ochratoxin (OTA) is one of the most abundant food contaminating mycotoxins and is commonly present in the food chain. Many of the effects associated with OTA, appear to be mediated through oxidative stress. Although the toxicity of OTA is fairly well characterized, antidotes for alleviating the toxicity are sparsely reported. Dietary antioxidants have gained much importance in the recent years for their antioxidative and therapeutic properties. In the present study the therapeutic strategy was directed towards use of quercetin, a dietary antioxidant to combat OTA-induced toxicity in Vero cell line. Our results demonstrate that quercetin pre-treatment suppressed OTA-induced cytotoxicity and oxidative stress. It modulated OTA-induced alteration on the antioxidant defence through activation of Nrf2 pathway. Morphological studies by scanning electron microscopy (SEM) and cell cycle analysis indicated that quercetin prevented OTA-induced apoptosis. It also inhibited the activation of caspase cascade that leads to DNA fragmentation. Quercetin also exhibited antigenotoxic potential by attenuating OTA-induced DNA damage and micronucleus (MN) formation. The results of the study demonstrate for the first time that quercetin pre-treatment prevents OTA-induced oxidative stress and apoptosis in Vero cell line.  相似文献   
3.
The aim of this study was to examine whether oral supplementation of quercetin-rich onion peel extract (OPE) influences blood coagulation and arterial thrombosis in Sprague-Dawley (SD) rats. 24 male rats, 5 weeks old, were divided into three groups with different diets (C: control, 2 mg OPE: chow diet with 2 mg OPE supplementation, 10 mg OPE: chow diet with 10 mg OPE supplementation) for 6 weeks. Blood coagulation parameters including prothrombin time (PT), activated partial thromboplastin time (aPTT) and platelet aggregation were examined. The OPE did not affect blood cholesterol levels but significantly decreased blood triglyceride and glucose levels. PT, aPTT and platelet aggregation were not significantly different among all tested groups. However, in vivo arterial thrombosis was significantly delayed in groups that were fed 2 mg and 10 mg OPE diets compared to the control group. In addition, the OPE greatly diminished thrombin-induced expression of tissue factor in human umbilical vein endothelial cells (HUVECs), a coagulation initiator. In addition, extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways activated by thrombin treatment were prevented by the OPE pre-treatment. These results indicate that OPE may have anti-thrombotic effects through restricting the induced expression of tissue factor via down-regulating mitogen-activated protein kinase (MAPK) activation upon coagulation stimulus, leading to the prolongation of time for arterial thrombosis.  相似文献   
4.

Ethnopharmacological relevance

Quercetin is a ubiquitous flavonoid that is present in numerous plants that are utilized in many different cultures for their nervous system and anticancer effects. To better understand the neuroprotective and antiproliferative activities of quercetin, we present a comprehensive review of the divergent actions that contribute to the ethnopharmacological profile of these plants.

Results

The pharmacological activities of quercetin that modulate antioxidation/oxidation/kinase-signaling pathways might be differentially elicited in neurons compared with malignant cells, ultimately promoting cell survival or death in a cell type- and metabolism-specific manner. Whereas the broad antioxidation and anti-inflammatory activities of quercetin are important for neuronal survival, the oxidative, kinase- and cell cycle-inhibitory, apoptosis-inducing effects of quercetin are essential for its anticancer effects. The diverse mechanistic interactions and activities of quercetin that modulate the phosphorylation state of molecules as well as gene expression would alter the interconnected and concerted intracellular signaling equilibrium, either inhibiting or strengthening survival signals. These mechanisms, which have been mainly observed in in vitro studies, cannot be easily translated into an explanation of the divergent simultaneous neuroprotective and anticancer effects observed in vivo. This is in part due to low bioavailability in plasma and in the brain, as well as the nature of the actual active molecules.

Conclusions

Numerous studies have demonstrated the beneficial effects of chronic quercetin intake, which is ethnopharmacologically meaningful, as many plants that are chronically ingested by people contain quercetin. Although quercetin and quercetin-containing plants exhibit potential as therapeutic modalities in neuropathology and in cancer, the data collectively highlight the need to elucidate issues such as bioavailability as well as its correlation with effectiveness at biomarkers in vivo. There would be an increased potentential of these plants for chemoprevention and neuropathology prevention.  相似文献   
5.
目的 探讨槲皮素对大鼠子宫内膜异位症模型的异位内膜是否具有抑制作用,以及其抑制作用与热休克蛋白70(HSP70)和血管内皮生长因子(VEGF)表达之间的关系. 方法 通过手术方法 建立大鼠子宫内膜异位症模型,4周后测量异位内膜体积,将造模成功的大鼠分为4组,分别每日灌喂槲皮素、丹那唑、槲皮素+丹那唑以及安慰剂,持续治疗3周后热休克并处死大鼠,测量异位内膜体积并取出异位内膜,检测组织学结构,并采用免疫组化法检测异位内膜组织中HSP70和VEGF的表达. 结果 与安慰剂相比,槲皮素[100 mg/(kg·d)]、丹那唑[36 mg/(kg·d)]和槲皮素+丹那唑联合治疗显著减小了异位内膜的体积,但槲皮素、丹那唑及联合治疗后的异位内膜体积差异无统计学意义.与安慰剂和丹那唑相比,槲皮素和联合治疗明显抑制了异位内膜组织中HSP70和VEGF的表达,且在后两个治疗组中HSP70及VEGF的表达差异无统计学意义. 结论 槲皮素可抑制大鼠子宫内膜异位症模型中异位内膜的生长,并且其抑制效应可能与HSP70和VEGF的表达下降有关,值得进一步研究.  相似文献   
6.
目的:通过观察槲皮素对宫颈癌HeLa细胞nm23 mRNA的表达水平,分析槲皮素体外诱导HeLa细胞凋亡的机制。方法:按槲皮素浓度分为10,20,40μmol/L和空白对照组、溶剂对照组,分别培养24,48,72 h后,采用逆转录-多聚酶链反应(RT-PCR)方法检测细胞内nm23 mRNA的表达水平。结果:20,40μmol/L槲皮素组在24,48 h时HeLa细胞nm23 mRNA的表达分别较空白对照组、溶剂对照组明显上升(均为P<0.01)。结论:槲皮素可能通过促进转移抑制基因nm23的表达而发挥抗肿瘤作用。  相似文献   
7.
The present paper reports cyclic voltammetry and a.c. impedance spectroscopy studies on adsorption and electrooxidation of quercetin (3,3′,4′,5,7-pentahydroxyflavone) compound at glassy carbon electrode surface in 0.1 M sodium acetate–acetic acid buffer in 90% methanol solution. The resulted information provided support for a cascade electrooxidation mechanism, which process commences with oxidation of catechol hydroxyl groups and involves strongly adsorbed reaction intermediate. The significance of each oxidation step is explained through associated charge-transfer resistance (derived for all individual oxidation steps and electrosorption of quercetin) and capacitance parameters. This work also presents an original way to regenerate the surface of glassy carbon electrode (after being blocked by quercetin oxidation products) through voltammetric cycling over the potential range negative to the hydrogen reversible potential. The above is realized by means of in situ evolved hydrogen, which species is capable of electrochemically reducing products formed during the cascade electrooxidation reaction of quercetin.  相似文献   
8.
槲皮素广泛存在于蔬菜和水果中,属于黄酮类物质,研究发现其对多种肿瘤细胞具有抑制作用,包括乳腺癌、前列腺癌、肝癌、食管癌、卵巢癌等.目前在体内和体外研究均发现槲皮素对结肠癌具有抑制作用,其不仅抑制结肠癌细胞的增殖、诱导癌细胞的凋亡.同时可以减少结肠畸形腺隐窝的数目.槲皮素抑癌的具体作用机制目前还不明确,可能是通过调节多个...  相似文献   
9.
目的:研究黄芩素等9种中药单体对艰难梭菌的体外抑菌活性。方法:采用滤纸片法测定9种中药单体对艰难梭菌的抑菌活性,筛选出其中活性较好的中药单体;采用琼脂稀释法测定其最低抑菌浓度(MIC);微量肉汤稀释法测定最低杀菌浓度(MBC);滤纸片法测定pH稳定性以及棋盘法测定与万古霉素联合的抑菌作用。结果:黄芩素、槲皮素对艰难梭菌抑菌活性较好,MIC值分别为1.25、2.5 mg·mL-1,MBC值分别为1.25、5 mg·mL-1,在pH 3~8范围内具有良好稳定性,与万古霉素有协同抑菌作用。结论:黄芩素、槲皮素在体外对艰难梭菌有良好的抑菌活性,为治疗艰难梭菌感染提供了一种新思路。  相似文献   
10.
目的 借助网络药理学的方法,探究两组王琦教授新冠肺炎预防方(简称预防方)预防新型冠状病毒肺炎(COVID-19)的分子靶点和机制。方法 通过TCMSP数据库检索并筛选其活性成分及其作用靶点,通过Uniprot数据库进行蛋白标准化处理。从Genecards数据库中以“Novel coronavirus pneumonia”为关键词搜索获取COVID-19的靶标,构建相交靶点韦恩图。通过cytoscape3.7.2构建PPI蛋白互作网络,寻找富集数目最多的靶点。通过R语言对预防方治疗COVID-19的靶点进行GO和KEGG富集分析,并绘制气泡图。结果 预防方与新冠肺炎相关靶点涉IL-6、TNF、CXCL8、VEGFA、MMP9;GO功能富集分析分别获得53、57条通路;27、29条KEGG相关信号通路。结论 王琦教授新冠肺炎预防方中的主要活性成分为槲皮素、山奈酚、木犀草素、β-谷甾醇、植物甾醇等,可能通过作用于IL-6、TNF、CXCL8、VEGFA、MMP9、CXCL8、IL10、CCL2、IL1B等靶点和介导TNF信号通路、T细胞受体信号通路、Toll样受体信号通路等发挥作用,从而促进免疫反应、炎症反应及细菌防御反应,预防COVID-19。  相似文献   
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