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41.
C-PG血小板聚集试验在单采血小板捐献者筛查中的应用 总被引:1,自引:1,他引:1
本研究探讨以阳离子没食子酸丙酯(C-PG)为激活剂的血小板聚集试验用于单采血小板捐献者筛查的可行性,并调查血小板献血者血小板功能缺陷的发生率.测定不同浓度C-PG诱导的健康献血者的血小板聚集率,以确定C-PG的最适应用浓度;检测30名志愿者服用阿司匹林前和服药24小时后的血小板聚集率,以确定血小板功能不良的筛查界点值;检测483例血小板捐献者的C-PG诱导的血小板聚集率,并对聚集功能不良者进行活化血浆凝固时间(APCT)测定.结果表明:血小板聚集率随C-PG浓度的增加而升高,当C-PG浓度达200μmol/L时,血小板聚集率达最高;服用阿司匹林24小时后的血小板聚集率与服药前相比,均表现明显减低(P<0.001),但以C-PG诱导180秒时的血小板聚集率减低最显著.血小板功能不良的筛查界点值确定为C-PG诱导180秒时的血小板聚集率小于20%;在483例血小板捐献者中,检出25例有血小板聚集功能不良,其中有11例表现为血小板促凝血活性减低.结论:C-PG诱导的血小板聚集试验能有效的检出血小板功能不良者,适用于血小板捐献者血小板功能的筛选;在血小板献血者中,血小板功能缺陷者的检出率大约为5%. 相似文献
42.
目的:观察不同浓度棓丙酯对大鼠离体小肠收缩活动及小鼠在体小肠推进运动的影响。方法:采用大鼠离体肠管和小鼠小肠推进运动实验,考察棓丙酯对肠平滑肌运动的影响。结果:棓丙酯在10~80μmol/L浓度范围内剂量依赖性抑制大鼠离体小肠平滑肌收缩(P〈0.05,P〈0.01),拮抗乙酰胆碱及组胺引起的促进收缩作用(P〈0.01),且相加阿托品、槲皮素引起的抑制收缩作用(P〈0.01)。棓丙酯高剂量组(200mg/kg)、中剂量组(100mg/kg)对小鼠在体小肠推进运动有明显的抑制作用(P〈0.05,P〈0.01)。结论:棓丙酯对大鼠、小鼠肠平滑肌运动具有明显抑制作用。 相似文献
43.
44.
目的:建立同时测定绿茶中表没食子儿茶素没食子酸酯(EGCG)和咖啡因含量的方法。方法:采用高效液相色谱法。色谱柱为DiamonsilTMC18(200mm×4.6mm,5μm),流动相为甲醇-0.1%冰醋酸水溶液(25:75),检测波长为278nm,流速为1.0mL.min-1,柱温为30℃。结果:EGCG和咖啡因的进样量分别在1.25~10.00μg(r=0.9994)和0.25~2.00μg(r=0.9996)范围内与各自峰面积积分值呈良好的线性关系;平均加样回收率分别为98.06%和99.37%,RSD分别为1.05%和1.44%(n均为6)。结论:该方法简便、准确、重复性好,可用于绿茶的质量控制。 相似文献
45.
目的 观察不同浓度表没食子儿茶素没食子酸酯(EGCG)对高糖造成氧化应激状态下体外小鼠足细胞损害的作用并探讨其机制。 方法 以高糖(25 mmol/L)培养的小鼠足细胞为研究对象,维生素E培养为对照。首先以MTT法检测细胞活力,再在激光共聚焦显微镜下以CM-H2DCFDA荧光探针观察不同浓度EGCG(0.2、10、100 μmol/L)刺激足细胞6、12、24 h后活性氧(ROS)生成,并以流式细胞仪定量分析ROS平均荧光强度。RT-PCR法检测足细胞内ROS产生的主要通路NADPH氧化酶各亚基mRNA(ph22phox、p47phox、p67phox)的表达。 结果 高糖刺激下6 h,足细胞ROS生成显著增加(P < 0.01)。正常糖组和甘露醇组培养12 h ROS生成无显著增加(P > 0.05)。EGCG 0.2 μmol/L作用6 h可显著降低高糖环境下体外小鼠足细胞ROS水平(P < 0.01)。与高糖组比较,EGCG(100 μmol/L)显著减少NADPH氧化酶亚基p22phox和p67phox mRNA表达(均P < 0.05)。与维生素E组比较,EGCG(0.2 μmol/L)和维生素E(0.2 mmol/L)协同作用组显著减少p47phox mRNA表达(P < 0.05)。 结论 EGCG能缓解高糖环境下体外足细胞氧化应激状态,对高糖培养下足细胞有保护作用。 相似文献
46.
Verapamil is known to be a P‐glycoprotein (P‐gp) substrate and norverapamil is formed via hepatic cytochrome P450 (CYP 3A) in the rat. Epigallocatechin gallate (EGCG), a flavonoid, was reported to be an inhibitor of both P‐gp and CYP3A. Hence, it could be expected that EGCG could alter the pharmacokinetics of verapamil. In this study, 9 mg/kg verapamil was administered orally to Sprague–Dawley rats 30 min after the oral administration of 2 and 10 mg/kg of oral EGCG. Compared with the controls, the AUC values of both verapamil (74.3% and 111% increase for 2 and 10 mg/kg EGCG, respectively) and norverapamil (51.5% and 87.2% increase for 2 and 10 mg/kg EGCG, respectively) were significantly greater in the presence of EGCG. However, compared with the controls, both the AUC and the relative bioavailability of verapamil were significantly (p<0.01) increased by 74.3–111% in the presence of EGCG. The likely explanation is inhibition of P‐gp. Inhibition of CYP3A would increase the AUC of verapamil but decrease the AUC of norverampil. However, inhibition of P‐gp would lead to an increase of AUC of both verapamil and norverapamil. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
47.
Gabriela Mazzanti Francesca Menniti-Ippolito Paola Angela Moro Federica Cassetti Roberto Raschetti Carmela Santuccio Sabina Mastrangelo 《European journal of clinical pharmacology》2009,65(4):331-341
Purpose To review the current literature on suspected green tea-related hepatic reactions and to describe two new cases reported within
the framework of the Italian surveillance system of natural health products.
Results A literature search of publication between 1999 and October 2008 retrieved 34 cases of hepatitis. Histological examination
of the liver revealed inflammatory reactions, cholestasis, occasional steatosis, and necrosis. A positive dechallenge was
reported in 29 cases. There was one reported death. A positive rechallenge occurred in seven cases (20%). In the two new cases,
the causality assessment was judged as “possible” according to the RUCAM score.
Conclusions Our analysis of the published case reports suggests a causal association between green tea and liver damage. The hepatotoxicity
is probably due to (-)-epigallocatechin gallate or its metabolites which, under particular conditions related to the patient’s
metabolism, can induce oxidative stress in the liver. In a few cases, toxicity related to concomitant medications could also
be involved. 相似文献
48.
Kuo-Chi Chang Jia Jang Yang Elizabeth Che-Hsiang Wang-Hsu Tsai-Hsien Chiu Fu-Chun Hsu 《Neuroscience letters》2009
(−)Epigallocatechin-3-gallate (EGCG), a tea catechin, has been known to cause many biological actions, such as anxiolytic and hypotensive effects in behavioral studies. However, to date, few reports investigate its neuronal modulation. In this study, intracellular recording was used to test the neuronal modulation of different catechins on locus coeruleus (LC) neuron, which has been demonstrated to be affected by cardiovascular function regulation and stressful events. Several catechins (1–1000 μM) were tested, including: (−)catechin (C), (−)catechingallate (CG), (−)epicatechin (EC), (−)epicatechin-3-gallate (ECG), (−)epigallocatechin (EGC) and EGCG. The results showed that catechins EC, ECG, EGC and EGCG could inhibit the spontaneous firing of the LC neurons; furthermore, these catechins show potency and efficacy in the order of EGCG > ECG > EC ≈ EGC. Among the tested catechins, EGCG was the most potent in inhibiting LC's spontaneous firing with IC50 of 20.5 μM. This caused us to further examine the EGCG's desensitization and tolerance properties. When continuously administering EGCG at 1–300 μM for 20 min, no acute desensitization appeared. However, repeated applications of 300 μM EGCG at 5 min each time showed different results. The second and third applications induced less responses compared to that of the first application, suggesting a development of tolerance towards EGCG in inhibiting LC neuronal activity. Our data suggest that EGCG can inhibit LC neuron's spontaneous firing in a dose-dependent manner, with developed tolerance only when high concentration of EGCG is repeatedly applied. 相似文献
49.
Dong Wook Shin Sang Min Lee Min Jeong Song Tae Ryong Lee Han Kon Kim Minsoo Noh 《Biochemical pharmacology》2009,77(1):125-171
Green tea intake has been shown to confer various health benefits to patients suffering from metabolic disorders. Here, we studied the effect of several major green tea polyphenols on adipocyte differentiation in human bone marrow mesenchymal stem cells (hBM-MSCs) and compared it to the effect of representative antidiabetic drugs. (−)-Catechin was the most potent of the eight green tea polyphenols evaluated in promoting adipocyte differentiation in hBM-MSCs, and this effect was dose-dependent. (−)-Catechin increased the mRNA levels of various adipogenic markers, such as adiponectin, peroxisome proliferator-activated receptor gamma (PPARγ), FABP4, and LPL, as measured during adipocyte differentiation in hBM-MSCs. In addition, (−)-catechin upregulated the secretion of adiponectin in hBM-MSC culture. Using a reporter gene assay and a competitive ligand binding study, (−)-catechin also significantly activated PPARγ in a dose-dependent fashion; however, (+)-catechin, the enantiomer of (−)-catechin, was not effective as a PPARγ agonist, which seems to imply that the effect of (−)-catechin on PPARγ is stereospecific. In conclusion, our data suggest that (−)-catechin promotes adipocyte differentiation and increased sensitivity to insulin in part by direct activation of PPARγ, which could be at the basis of the observed pharmacological benefits of green tea intake in reducing the risk of type 2 diabetes. 相似文献
50.
Mare Cudic Gayle D. Burstein Gregg B. Fields Janelle Lauer‐Fields 《Chemical biology & drug design》2009,74(5):473-482
Polyphenolic natural products from green tea and red wine have been identified as metalloproteinase inhibitors. Members from the flavonoid and stilbene families found to possess metalloproteinase inhibitory activities include (?)‐epigallocatechin gallate, (?)‐epicatechin gallate and piceatannol, but their minimally active pharmacophores have not been evaluated. The present study has examined compounds that are structural components of or structurally related to (?)‐epigallocatechin gallate, (?)‐epicatechin gallate and piceatannol for inhibition of aggrecanases and four representative matrix metalloproteinases. Piceatannol and pyrogallol were found to inhibit all aggrecanases and matrix metalloproteinases studied, indicating a crucial reliance on multiple hydroxyl groups for (?)‐epigallocatechin gallate, (?)‐epicatechin gallate and piceatannol activity. Differences in Ki values for pyrogallol as determined with two structurally distinct substrates indicated the likelihood that this compound binds in a non‐competitive modality. Further analysis showed that pyrogallol acts as an exosite inhibitor, consistent with the action of (?)‐epigallocatechin gallate. In contrast, piceatannol was shown to be a competitive binding inhibitor and showed no differences in apparent Ki values as determined by distinct substrates, illustrating the benefits of using two structurally distinct substrates to assist the analysis of protease inhibitors. The compounds identified here could be utilized to develop novel metalloproteinase probes or as fragment components of more active inhibitors. 相似文献