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1.
目的:探讨苹果多酚通过调节腺苷酸活化蛋白激酶/沉默信息调节因子1(AMP-activated protein kinase/Sirtuin1,AMPK/SIRT1)信号通路对脂多糖(lipopolysaccharide,LPS)诱导的人肺泡上皮细胞(A549)自噬反应的影响。方法:使用不同浓度的苹果多酚提取物(apple polyphenol extract,APE)预处理A549细胞2 h后,LPS诱导A549细胞培养24 h,MTT法检测增殖活性,筛选APE最佳预处理浓度;将A549细胞分为对照组、LPS组(3 mg/L LPS)、LPS+APE组(3 mg/L LPS+20 μg/mL APE)、APE+Compound C组(3 mg/L LPS+20 μg/mL APE+50 μmol/L Compound C),免疫荧光染色观察A549细胞自噬;流式细胞术检测A549细胞凋亡;Western blot法检测细胞中自噬相关蛋白及AMPK/SIRT1通路相关蛋白表达水平。结果:与对照组比较,经LPS诱导的A549细胞增殖活性、自噬水平、LC3Ⅱ/LC3Ⅰ、Beclin-1、SIRT1、p-ULK1/ULK1、p-AMPK/AMPK蛋白表达降低,p62蛋白表达及细胞凋亡率升高(P<0.05);与LPS组比较,LPS+APE组细胞增殖活性、自噬水平、LC3Ⅱ/LC3Ⅰ、Beclin-1、SIRT1、p-ULK1/ULK1、p-AMPK/AMPK蛋白表达水平显著升高,p62蛋白表达及细胞凋亡率显著降低(P<0.05);与LPS+APE组比较,APE+Compound C组A549细胞增殖活性、自噬水平、LC3Ⅱ/LC3Ⅰ、Beclin-1、SIRT1、p-ULK1/ULK1、p-AMPK/AMPK蛋白表达水平显著降低,p62蛋白表达及细胞凋亡率显著升高(P<0.05)。结论:苹果多酚通过激活AMPK/SIRT1 信号通路提高LPS诱导的肺上皮细胞自噬,降低细胞凋亡。  相似文献   
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Objective: To investigate the effects of emodin on inflammation and autophagy in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages and reveal its underlying mechanism. Methods: 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay was conducted to find the appropriate dose for emodin. RAW264.7 cells pretreated with different concentrations (0–50 μ mol/L) of emodin or vehicle for 2 h prior to exposure to LPS for 16 h. Cell morphology was examined and propidium iodide staining was used to examine cell cycle. Expressions of inflammation-related proteins [nuclear factor-kappaB (NF-κ B) and I-kappaB (Iκ B)α ] and autophagy-related proteins [light chain (LC)3, P62/sequestosome 1, mammalian target of rapamycin (mTOR), and p-mTOR] were examined using Western blot analysis. Expression of inflammation-related cytokines including tumor necrosis factor (TNF)-α , interleukin (IL)-1β and IL-6 were detected by enzyme-linked immunosorbent assay. Autophagy was examined with LC3B fluorescence intensity and aggregation. The effect of emodin on autophagy was conducted with an autophagy inhibitor, 3-methyladenine (3-MA). Results: The expression of NF-κ B in LPS-induced cells was significantly increased (P<0.01) and simultaneously Iκ Bα decreased compared with the normal cell (P<0.05). The expressions of TNF-α , IL-1β , and IL-6 proteins in the LPS-induced RAW264.7 cells were significantly higher than in the normal cell (P<0.05 or P<0.01). LPS increased the percentage of cells in the G0/G1 phase, which was recovered by emodin at different doses (12.5, 25, and 50μ mol/L, P<0.05 or P<0.01). The medium dose (25 μ ml/L) emodin decreased the expressions of NF-κ B, P62 and p-mTOR (P<0.01) and increased Iκ Bα expression, LC3B Ⅱ /Ⅰ ratio as well as LC3B fluorescence intensity (P<0.05 or P<0.01). Meanwhile, the enhanced autophagic effects of emodin, such as the increment of LC3BⅡ / ratio and the decrement of P62 expression, were suppressed by autophagy inhibitor 3-MA. Conclusion: Emodin could inhibit inflammation of mice RAW264.7 macrophages induced by LPS, possibly through activating autophagy.  相似文献   
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Increasing evidence suggests that human epidermal melanocytes play an important role in the skin immune system; however, a role of their pigmentation in immune and inflammatory responses is poorly examined. In the study, the expression of Toll‐like receptor 4 (TLR4) and inflammatory cytokines and chemokines by cultured normal melanocytes derived from lightly and darkly pigmented skin was investigated after cell stimulation with lipopolysaccharide (LPS). The basal TLR4 mRNA level in heavily pigmented cells was higher as compared to their lightly pigmented counterparts. Melanocyte exposure to LPS upregulated the expression of TLR4 mRNA and enhanced the DNA‐binding activity of NF‐κB p50 and p65. We found substantial differences in the LPS‐stimulated expression of numerous genes encoding inflammatory cytokines and chemokines between the cells with various melanin contents. In lightly pigmented melanocytes, the most significantly upregulated genes were nicotinamide phosphoribosyltransferase (NAMPT/visfatin), the chemokines CCL2 and CCL20, and IL6, while the genes for CXCL12, IL‐16 and the chemokine receptor CCR4 were the most significantly upregulated in heavily pigmented cells. Moreover, the lightly pigmented melanocytes secreted much more NAMPT, CCL2 and IL‐6. The results of our study suggest modulatory effect of melanogenesis on the immune properties of normal epidermal melanocytes.  相似文献   
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A high salt diet (HSD) is among the most important risk factors for many diseases. One mechanism by which HSD aggravates cerebral ischemic injury is independent of blood pressure changes. The direct role of HSD in inflammation after cerebral ischemia is unclear. In this research, after twenty-one days of being fed a high salt diet, permanent focal ischemia was induced in mice via operation. At 12 h and 1, 3 and 5 days postischemia, the effects of HSD on the lesion volume, microglia polarization, aldose reductase (AR) expression, and inflammatory processes were analyzed. We report that in mice, surplus dietary salt promotes inflammation and increases the activation of classical lipopolysaccharide (LPS)-induced microglia/macrophages (M1). This effect depends on the expression of the AR protein in activated microglia after permanent middle cerebral artery ligation (pMCAL) in HSD mice. The administration of either the AR inhibitor Epalrestat or a p38-neutralizing antibody blocked the polarization of microglia and alleviated stroke injury.In conclusion, HSD promotes polarization in pro-inflammatory M1 microglia by upregulating the expression of the AR protein via p38/MAPK, thereby exacerbating the development of ischemia stroke.  相似文献   
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目的:探讨脂多糖(LPS)对人乳腺癌MDA-MB-231细胞中上皮间质转化(EMT)标志物及β-连环素(β-catenin)表达的影响,阐明其可能机制。方法:人乳腺癌MDA-MB-231细胞分为对照组和不同浓度(5、10、20和40 mg·L-1)LPS组,倒置显微镜观察各组MDA-MB-231细胞的形态表现,免疫荧光实验检测各组MDA-MB-231细胞中β-catenin表达及定位,实时荧光定量PCR(RT-qPCR)法和Western blotting法检测各组MDA-MB-231细胞中EMT标志物E-钙黏蛋白(E-cadherin)、波形蛋白(Vimentin)和β-catenin mRNA及蛋白表达水平。结果:对照组MDA-MB-231细胞形态表现为上皮细胞表型,不同浓度LPS组MDA-MB-231细胞形态表现为间质细胞表型。免疫荧光实验,β-catenin表达定位主要在细胞核。与对照组比较,不同浓度LPS组细胞中Vimentin和β-catenin mRNA及蛋白表达水平明显升高(P<0.05或P<0.01),以20 mg·L-1LPS组升高最为明显;与对照组比较,不同浓度LPS组细胞中E-cadherin mRNA和蛋白表达水平明显降低(P<0.05或P<0.01),以20 mg·L-1 LPS组降低最为明显。结论:LPS通过下调E-cadherin表达、上调Vimentin表达促进乳腺癌MDA-MB-231细胞发生EMT、侵袭和转移,其作用机制可能与Wnt/β-catenin信号通路有关。  相似文献   
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