全文获取类型
收费全文 | 15824篇 |
免费 | 740篇 |
国内免费 | 376篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 153篇 |
妇产科学 | 299篇 |
基础医学 | 1981篇 |
口腔科学 | 242篇 |
临床医学 | 1049篇 |
内科学 | 2079篇 |
皮肤病学 | 211篇 |
神经病学 | 864篇 |
特种医学 | 264篇 |
外国民族医学 | 6篇 |
外科学 | 779篇 |
综合类 | 2387篇 |
现状与发展 | 1篇 |
预防医学 | 770篇 |
眼科学 | 225篇 |
药学 | 3496篇 |
6篇 | |
中国医学 | 1333篇 |
肿瘤学 | 760篇 |
出版年
2023年 | 206篇 |
2022年 | 319篇 |
2021年 | 563篇 |
2020年 | 635篇 |
2019年 | 454篇 |
2018年 | 391篇 |
2017年 | 625篇 |
2016年 | 642篇 |
2015年 | 577篇 |
2014年 | 1390篇 |
2013年 | 2132篇 |
2012年 | 1776篇 |
2011年 | 1576篇 |
2010年 | 1151篇 |
2009年 | 947篇 |
2008年 | 790篇 |
2007年 | 411篇 |
2006年 | 361篇 |
2005年 | 334篇 |
2004年 | 265篇 |
2003年 | 179篇 |
2002年 | 134篇 |
2001年 | 56篇 |
2000年 | 38篇 |
1999年 | 29篇 |
1998年 | 52篇 |
1997年 | 43篇 |
1996年 | 42篇 |
1995年 | 29篇 |
1994年 | 23篇 |
1993年 | 16篇 |
1991年 | 11篇 |
1990年 | 21篇 |
1989年 | 14篇 |
1988年 | 20篇 |
1987年 | 15篇 |
1986年 | 9篇 |
1985年 | 66篇 |
1984年 | 79篇 |
1983年 | 87篇 |
1982年 | 89篇 |
1981年 | 59篇 |
1980年 | 60篇 |
1979年 | 42篇 |
1978年 | 37篇 |
1977年 | 28篇 |
1976年 | 24篇 |
1975年 | 24篇 |
1974年 | 21篇 |
1973年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
本文报告65例双炔失碳酯配伍d1-15甲基PGF_(2α)(以下简称PG)抗早孕结果并与33例丙睾配伍PG抗早孕结果进行比较。结果显示,双炔失碳酯组完全流产59例,占90%;不全流产3例,占5%;失败3例,占5%;总有效率95%。丙睾组完全流产27例,占82%;不全流产6例,占18%;总有效率100%。两组总有效率无显著差异;完全流产率无显著差异;但不全流产率有明显差异(P<0.05)。药流后点滴出血天数,双炔失碳酯组平均为8.1±5.0天;丙睾组平均为18.9±19.1天;两组有明显差别(P<0.05)。双炔失碳酯经阴道给药后无一例发生心、肝、肾功能变化。 相似文献
23.
Alpha-glucosidase activity and sperm motility 总被引:2,自引:0,他引:2
We correlated the activity of alpha-glucosidase in seminal plasma with the motility and differential motility of sperm. Significant positive correlations were found between the alpha-glucosidase activity and both motility and the percentage sperm with good forward progression. This supports the use of alpha-glucosidase in semen as a marker of epididymal function and specifically of the development of motility. 相似文献
24.
TNF-α在沙漠干热环境下猪腹部肠管火器伤后肝组织中的表达 总被引:3,自引:3,他引:0
目的探讨沙漠干热环境下猪腹部肠管火器伤后肝脏组织TNF-α的表达和肝功能的变化。方法沙漠干热环境组和常温环境组健康长白仔猪各42头随机等分为对照组和伤后1、2、4、8、12 h和24 h组,实验组建立腹部火器伤肠管穿透模型后,用免疫组化及图像分析法测定各组肝脏组织内TNF-α的表达,同时测定血清中AST水平。结果伤后各组肝组织TNF-α表达明显高于对照组,沙漠干热环境组于伤后2 h和8 h出现2个高峰;常温环境组于伤后2 h和12 h出现2个高峰。血清AST水平于伤后显著增高,并于伤后2 h出现第1个高峰,沙漠干热环境组和常温环境组分别于伤后8 h和12 h出现第2个高峰。结论沙漠干热环境下腹部肠管火器伤后肝脏TNF-α的表达增加并与AST的变化趋势一致,而且峰值较常温组提前出现,提示TNF-α在腹部肠管火器伤后肝损伤过程中可能起重要作用。 相似文献
25.
目的探讨缺氧诱导因子-1α(HIF-1α)在ESWL致肾脏损伤中的作用及黄芪是否通过调节HIF-1α的表达而发挥对肾脏的保护作用。方法45只家兔随机分为对照组、ESWL损伤组和黄芪治疗组,每组15只,除对照组外,所有动物接受ESWL处理(18kV,1 500次)。黄芪治疗组家兔于冲击前3d至后2d,每天注射黄芪注射液2.0g/kg。2周后处死家兔,取肾脏HE染色观察肾组织形态学改变,免疫组织化学染色观察HIF-1α在肾脏中的表达。结果ESWL处理后肾小管上皮细胞肿胀、脱落,小管内可见大量管型,肾间质大量炎细胞浸润;黄芪治疗组以上病变显著减轻。ESWL损伤组HIF-1α显著表达于肾小管上皮细胞及间质,黄芪能够明显抑制HIF-1α的表达。结论HIF-1α参与了ESWL对肾脏的损伤,黄芪可能通过抑制HIF-1α的表达发挥对肾脏的保护作用。 相似文献
26.
Prospect for enzyme therapy in glycogenosis II variants: a study on cultured muscle cells 总被引:4,自引:0,他引:4
A. T. van der Ploeg P. A. Bolhuis R. A. Wolterman J. W. Visser M. C. B. Loonen H. F. M. Busch A. J. J. Reuser 《Journal of neurology》1988,235(7):392-396
Summary Impairment of skeletal muscle function is the common feature of distinct clinical forms of glycogenosis type II. In the present study, muscle cultures from different patients were used to investigate the cause of clinical heterogeneity and the feasibility of enzyme replacement therapy. The activity of acid -glucosidase appears to be the primary factor in determining the extent of lysosomal glycogen storage in muscle, and thereby the clinical severity of the disease. Neutral -glucosidases do not seem influencial. Correction of the enzymatic defect was achieved in skeletal muscle cultures from patients by administration of a high-uptake form of acid -glucosidase, purified from human urine. The enzyme reaches the lysosomes, including the glycogen storage vacuoles, and the lysosomal glycogen content is reduced to control level. In normal muscle cells 20% of the total cellular glycogen pool is segregated in lysosomal compartments. This percentage is higher than in fibroblasts, which may partly explain why muscles are more prone to store glycogen. The relevance of this study for enzyme therapy is discussed. 相似文献
27.
28.
Immunoglobulin mimicry by Hepatitis C Virus envelope protein E2 总被引:4,自引:0,他引:4
Hu YW Rocheleau L Larke B Chui L Lee B Ma M Liu S Omlin T Pelchat M Brown EG 《Virology》2005,332(2):538-549
Hepatitis C virus (HCV) establishes persistent infection in the majority of infected individuals. The currently accepted hypothesis of immune evasion by antigenic variation in hypervariable region 1 (HVR1) of glycoprotein E2 does not however, explain the lack of subsequent immune recognition. Here, we show that the N-terminal region of E2 is antigenically and structurally similar to human immunoglobulin (Ig) variable domains. E2 is recognized by anti-human IgG antibodies and also possesses common amino acid (aa) sequence features of the conserved v-gene framework regions of human Ig light chains in particular but also heavy chains and T cell receptors. Using a position specific scoring system, the degree of similarity of HVR1 to Ig types correlated with immune escape and persistence in humans and experimentally infected chimpanzees. We propose a unique role for threshold levels of Ig molecular mimicry in HCV biology that not only advances our concept of viral immune escape and persistent infection but also provides insight into host-dependent disease patterns. 相似文献
29.
We previously reported the expression profiles of 9 cytochrome P450 isozymes (CYPs) proteins and those of 40 CYPs genes in pregnant rat's liver, placenta and fetal liver after treatment with pregnenolone-16alpha-carbonitrile (PCN) or phenobarbital (PB). This study was carried out focusing on the gene expression profiles of Phase II drug metabolizing enzymes, Glutathione S-transferase isozymes (GSTs) and UDP-glycosyltransferase isozymes (UDPGTs). Fischer 344 (F344) pregnant rats were daily treated intraperitoneally with 50 mg/kg of PCN or 80 mg/kg of PB from 13 to 16 days of gestation (DG). They were sacrificed on 17 DG, and microarray analysis using Affymetrix Rat Expression Array 230 A was performed. Among 16 GSTs genes examined in this study, 7 genes were significantly induced in dam's liver and 3 genes in fetal liver, respectively, in the PCN-group, while 8 genes were significantly induced in dam's liver and 1 gene in fetal liver, respectively, in the PB-group. On the other hand, among 11 UDPGTs genes examined, 5 genes were significantly induced in dam's liver and 3 genes in fetal liver, respectively, in the PCN-group, while 5 genes were significantly induced in dam's liver and 1 gene in fetal liver, respectively, in the PB-group. There were no significant changes in the placenta of all groups. This is the first report of the gene expression profiles of Phase II drug metabolizing enzymes in pregnant rat and fetal livers and placenta after treatment with typical inducers of drug metabolizing enzymes. 相似文献
30.