全文获取类型
收费全文 | 21841篇 |
免费 | 1662篇 |
国内免费 | 848篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 547篇 |
妇产科学 | 370篇 |
基础医学 | 2564篇 |
口腔科学 | 185篇 |
临床医学 | 1540篇 |
内科学 | 3431篇 |
皮肤病学 | 270篇 |
神经病学 | 1751篇 |
特种医学 | 740篇 |
外国民族医学 | 1篇 |
外科学 | 1593篇 |
综合类 | 2911篇 |
现状与发展 | 1篇 |
预防医学 | 2038篇 |
眼科学 | 355篇 |
药学 | 3828篇 |
13篇 | |
中国医学 | 1027篇 |
肿瘤学 | 1073篇 |
出版年
2024年 | 22篇 |
2023年 | 270篇 |
2022年 | 513篇 |
2021年 | 815篇 |
2020年 | 769篇 |
2019年 | 591篇 |
2018年 | 637篇 |
2017年 | 745篇 |
2016年 | 893篇 |
2015年 | 850篇 |
2014年 | 1603篇 |
2013年 | 1873篇 |
2012年 | 1374篇 |
2011年 | 1721篇 |
2010年 | 1281篇 |
2009年 | 1310篇 |
2008年 | 1340篇 |
2007年 | 1128篇 |
2006年 | 1052篇 |
2005年 | 887篇 |
2004年 | 723篇 |
2003年 | 596篇 |
2002年 | 422篇 |
2001年 | 389篇 |
2000年 | 342篇 |
1999年 | 239篇 |
1998年 | 185篇 |
1997年 | 185篇 |
1996年 | 168篇 |
1995年 | 133篇 |
1994年 | 141篇 |
1993年 | 111篇 |
1992年 | 127篇 |
1991年 | 91篇 |
1990年 | 84篇 |
1989年 | 82篇 |
1988年 | 77篇 |
1987年 | 67篇 |
1986年 | 55篇 |
1985年 | 66篇 |
1984年 | 64篇 |
1983年 | 61篇 |
1982年 | 39篇 |
1981年 | 46篇 |
1980年 | 41篇 |
1979年 | 40篇 |
1978年 | 20篇 |
1977年 | 22篇 |
1976年 | 17篇 |
1974年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
51.
52.
Chronic kidney disease (CKD) patients in dialysis (HD) are considered to be submitted to a continuous oxidative stress. This stress can cause damage on DNA and, consequently, contribute to the high levels of DNA damage observed in these patients. Due to the well-known role of polyphenols as antioxidant agents we proposed its use to reduce the levels of genotoxicity present in HD-CKD patients. The objective of this study was to evaluate the antigenotoxic effects of unfermented grape juice (UGJ) on HD-CKD patients. The levels of DNA damage were analyzed using different biomarkers, such as breaks and oxidized DNA bases by the comet assay, chromosome damage by the micronucleus test. In addition, TEAC (Trolox equivalent antioxidant capacity) was also evaluated. Thirty-nine patients were followed for six months, of whom 25 were supplemented by UGJ and 14 were not supplemented. The obtained results showed a significant decrease in the underlying levels of oxidative DNA damage, in the supplemented group. Regarding the clinical parameters, LDL and cholesterol, were significantly reduced in the patients studied after the supplementation period, although cholesterol was also decreased in the non-supplemented patients. In conclusion, in our studied group the supplementation with UGJ reduced the levels of oxidative DNA damage of HD-CKD patients. 相似文献
53.
Ines Dallel Intidhar Ben Salem Abderrahmen Merghni Wassim Bellalah Fadoua Neffati Samir Tobji Maha Mastouri Adel Ben Amor 《The Angle orthodontist》2020,90(4):532
ObjectivesTo evaluate the effect of orthodontic appliances on physicochemical, biochemical, and oxidative stress changes in salivary parameters during treatment.Materials and MethodsA cohort study was conducted with 112 healthy patients. Salivary samples were taken at baseline, 1 month, and 9 months after placement of the orthodontic appliances used in treatment.ResultsA statistically significant difference was observed in certain examined salivary parameters, including enzymes, electrolytes, and oxidative stress markers.ConclusionsThe use of aligners had a lower prevalence of disturbing salivary parameters. Orthodontist must consider these changes to prevent the occurrence of white spot lesions. 相似文献
54.
55.
Using Tetrahymena thermophila as experimental models, the oxidative stress of triazole fungicides myclobutanil (MYC) and cyproconazole (CYP) was investigated. Results showed that 24-h EC50 values for MYC and CYP were 16.67 (13.37–19.65) and 20.44 (18.85–21.96) mg/L, respectively; 48-h EC50 values for MYC and CYP were 14.31 (13.13–15.42) and 18.76 (17.09–20.31) mg/L, respectively. Reactive oxygen species was significantly induced and cytotoxicity was caused by MYC and CYP by increasing propidium iodide (PI) fluorescence. Damage of regular wrinkles and appearing of small holes on the cell surface were observed by SEM. Furthermore, MYC and CYP also caused notable changes in enzyme activities and mRNA levels. Overall, the present study points out that MYC and CYP lead to oxidative stress on T. thermophila. The information presented in this study will provide insights into the mechanism of triazoles-induced oxidative stress on T. thermophila. 相似文献
56.
目的探讨联体尺动脉穿支皮瓣修复多指毁损伤的临床效果。方法回顾性分析2011年3月至2017年10月东莞长安新安医院收治的12例多指毁损伤患者,男8例,女4例,年龄(32.6±4.3)岁,范围18~56岁。4指毁损伤2例,3指毁损伤4例,2指毁损伤6例。皮肤软组织损伤位置均为远掌横纹或指掌横纹以远,指骨为近节以远。皮肤总缺损面积(135.6±12.3)cm^2,范围6.0 cm×16.0 cm^6.0 cm×35.0 cm,应用皮瓣总面积(143.5±11.2)cm^2,范围5.0 cm×20.0 cm^3.2 cm×47.0 cm(双侧前臂)。双前臂尺动脉穿支皮瓣5例,单侧7例,所有皮瓣均为2条以上穿支蒂。皮瓣均设计为长条状,螺旋缠绕包裹于伤指骨,皮瓣穿支动脉与相应指固有动脉或掌背动脉吻合,伴行静脉与相应指掌侧静脉或掌背静脉吻合,皮瓣浅静脉与相应指背静脉或掌背静脉吻合,皮瓣神经与相应指固有神经或掌背相应感觉神经吻合。供区除1例植皮外,其余均直接缝合。术后随访观察疗效,包括感觉、外观、血液循环、骨吸收及手运动功能、日常生活、恢复工作情况等。评价标准为中华医学会手外科学会断指再植功能评定试用标准。结果所有皮瓣均成活,1例皮瓣末稍有约1.5 cm×1.5 cm坏死,二期缝合修复。所有病例均获6个月至6.5年随访,平均16.7个月,皮瓣质地良好,无色素沉着,外观无臃肿,指端无瘢痕或磨损,两点辨距觉6~10 mm,平均8.6 mm。术后半年骨吸收发生率59.4%(19/32),指短缩平均0.8 cm,其中5例6指取髂骨植骨。伤指拿捏及持物功能部分恢复,日常生活无明显影响;患手握力平均达到健侧的60.3%。参照断指再植功能评定试用标准:优2例,良5例,差4例,劣1例,优良率58.3%(7/12)。供区外观可。结论联体尺动脉穿支皮瓣为多指毁损或脱套伤患者的临床修复提供了一种有益的思路和有效的手术方案,效果良好。 相似文献
57.
58.
59.
【摘要】 目的 探讨外源性胆绿素对中波紫外线(UVB)照射的HaCaT细胞光损伤的保护作用。方法 将HaCaT细胞分为加入0、0.1、1、10 μmol/L胆绿素并照射UVB的UVB组、0.1 μmol/L UVB组、1 μmol/L UVB组、10 μmol/L UVB组及不做处理的对照组。UVB照射剂量为30 mJ/cm2,照射后继续培养24 h,分别检测细胞活性氧(ROS)水平、超氧化物歧化酶(SOD)活力、丙二醛(MDA)含量,ELISA法检测各组细胞的炎症因子白细胞介素6(IL-6)、IL-8水平。多组间均数比较采用单因素方差分析,组间两两比较采用LSD-t检验。结果 UVB组、0.1 μmol/L UVB 组、1 μmol/L UVB组、10 μmol/L UVB组、对照组细胞ROS水平(3 613.33 ± 206.61、2 958.67 ± 193.87、2 678.33 ± 178.24、2 274.67 ± 118.81、1 905.67 ± 250.25)、SOD活力(24.41 ± 1.78、28.96 ± 2.21、29.75 ± 1.75、30.19 ± 2.29、37.52 ± 2.31)、MDA含量(5.61 ± 0.32、5.46 ± 0.55、4.65 ± 0.22、2.55 ± 0.93、1.31 ± 0.05)、IL-6水平、IL-8水平差异均有统计学意义(F值分别为 34.02、57.36、214.09、29.73、11.40,均P < 0.05),UVB组ROS水平、MDA含量及IL-6、IL-8水平均高于另4组(均P < 0.05),SOD活力均低于另4组(均P < 0.05)。结论 外源性胆绿素减轻UVB引起的HaCaT细胞的氧化损伤、减轻炎症反应和抑制脂质过氧化作用,对细胞光损伤有一定的保护作用。 相似文献
60.
Fahad Ali Rahul Smita Jyoti Ambreen Fatima Saba Khanam Falaq Naz Yasir Hasan Siddique 《Scientia pharmaceutica》2016,84(2):361-377
The present investigation was aimed at studying the possible role of curcumin against N-nitrosodiethylamine (NDEA)-induced toxicity in albino rats. Administration of NDEA to rats at a concentration of 0.1 mg/ml in drinking water ad libitum for 21 days produced toxicity in them, which was evident from histopathological changes in the rat livers, and increased levels of blood serum enzyme markers, i.e. aspartate transaminase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase. In addition, the levels of oxidative stress markers like lipid peroxidation (LPO), protein carbonyl (PCC), and glutathione-S-transferase (GST) activity were elevated and the total glutathione (GSH) content was reduced in the livers. The administration of curcumin to rats at concentrations of 10, 20, and 40 mg/ml in drinking water along with 0.1 mg/ml of NDEA for 21 days effectively suppressed NDEA-induced toxicity and also resulted in a dose-dependent reduction in the levels of blood serum enzyme markers (AST, ALT, ALP, and LDH). Moreover, LPO, PCC, and GST activity were reduced and the GSH level was increased upon the administration of curcumin along with NDEA. The results obtained for the comet assay in rat hepatocytes and blood lymphocytes showed a significant dose-dependent decrease in the mean tail length. The micronucleus assay performed on rat hepatocytes also showed a dose-dependent reduction in the frequency of micronucleated cells along with curcumin administration. These results suggest that curcumin has a protective role against NDEA-induced toxicity in albino rats. 相似文献