首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   74757篇
  免费   7930篇
  国内免费   4914篇
耳鼻咽喉   583篇
儿科学   1267篇
妇产科学   678篇
基础医学   6727篇
口腔科学   1513篇
临床医学   9128篇
内科学   9432篇
皮肤病学   775篇
神经病学   3443篇
特种医学   3112篇
外国民族医学   27篇
外科学   7407篇
综合类   15858篇
现状与发展   13篇
一般理论   2篇
预防医学   6464篇
眼科学   1999篇
药学   8224篇
  56篇
中国医学   5799篇
肿瘤学   5094篇
  2024年   308篇
  2023年   1127篇
  2022年   2815篇
  2021年   3682篇
  2020年   2981篇
  2019年   2373篇
  2018年   2407篇
  2017年   2526篇
  2016年   2290篇
  2015年   3335篇
  2014年   4259篇
  2013年   4573篇
  2012年   6395篇
  2011年   6612篇
  2010年   5128篇
  2009年   4365篇
  2008年   4816篇
  2007年   4658篇
  2006年   4424篇
  2005年   3676篇
  2004年   2983篇
  2003年   2709篇
  2002年   2153篇
  2001年   1705篇
  2000年   1270篇
  1999年   942篇
  1998年   508篇
  1997年   563篇
  1996年   400篇
  1995年   331篇
  1994年   305篇
  1993年   186篇
  1992年   144篇
  1991年   135篇
  1990年   120篇
  1989年   89篇
  1988年   84篇
  1987年   68篇
  1986年   57篇
  1985年   28篇
  1984年   18篇
  1983年   21篇
  1982年   7篇
  1981年   5篇
  1980年   3篇
  1979年   3篇
  1978年   2篇
  1976年   2篇
  1974年   2篇
  1970年   2篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
HBV-YMDD变异患者与中医虚实辨证关系初探   总被引:7,自引:1,他引:7  
目的 :初步探讨服用拉米夫定后HBV -YMDD变异患者中医辨证虚证、实证之间的关系。方法 :对服用拉米夫定半年以上的乙型慢性病毒性肝炎患者采用联合基因集团上海博华基因技术有限公司出品的迈科锐乙型肝炎病毒突变检测基因芯片 ,进行HBV -YMDD变异检测。出现HBV -YMDD者 ,根据中医基础理论 ,将其分为实证、虚证 ,来探讨HBV -YMDD变异患者中医虚、实辨证的关系。结果 :HBV -YMDD变异患者中实证变异率(38/ 4 8)明显高于虚证 (10 / 4 8) ,具有统计学意义。结论 :HBV -YMDD变异与虚、实辨证之间具有相关性。  相似文献   
102.
参附注射液在胃癌术前介入化疗中的作用   总被引:6,自引:1,他引:6  
研究参附注射液在胃癌术前介入化疗中的作用,将87例进展期胃癌患者分成两组。分别检测T细胞亚群、白细胞总数及淋巴细胞数量等。结果:参附组对CD3、CD4,CD4/CD8的提高作用显著高于化疗组,且能保持白细胞及淋巴细胞的数量。提示参附注射液可增强胃癌术前介入化疗的患者的细胞免疫功能。  相似文献   
103.
目的探讨膀胱癌细胞nm23蛋白表达量与丝裂霉素药物敏感性之间的相关性.为临床膀胱移行细胞癌治疗方案选择提供理论依据.方法对32例临床病理诊断为膀胱移行细胞癌标本采用S-P免疫组化和图像分析技术检测细胞的nm23蛋白表达量;同时采用MTT法测定膀胱癌细胞对丝裂霉素的药物敏感性.结果膀胱癌nm23表达量与MMC抗药指数相关,相关指数为0.890(P<0.001).结论膀胱癌nm23蛋白表达量与MMC抗药指数呈正相关.  相似文献   
104.
BACKGROUND: Chronic cyclosporine (CsA) nephrotoxicity is characterized by interstitial fibrosis and afferent arteriolar hyalinosis. L-arginine (L-Arg), the substrate for nitric oxide (NO) synthase and N-nitro-L-arginine-methyl ester (L-NAME), the NO synthase inhibitor, were shown to modulate acute CsA nephrotoxicity. However, the mechanism of fibrosis in chronic CsA nephrotoxicity remains unclear. Thus, we examined the effect of NO modulation on fibrosis and the expression of transforming growth factor-beta1 (TGF-beta1) and matrix proteins in chronic CsA nephrotoxicity. METHODS: Rats were administered CsA (7.5 mg/kg), CsA + L-Arg (1.7 g/kg), CsA + L-NAME (3.5 mg/kg), vehicle (VH), VH + L-Arg, and VH + L-NAME, and were sacrificed at 7 or 28 days. NO production, physiologic parameters, and histology were studied in addition to the mRNA expression of TGF-beta1, plasminogen activator inhibitor-1 (PAI-1) and the matrix proteins biglycan and collagens type I and IV by Northern and the protein expression of PAI-1 and fibronectin by enzyme-linked immunosorbent assay. RESULTS: While L-NAME strikingly reduced NO biosynthesis and worsened the glomerular filtration rate and CsA-induced fibrosis, L-Arg had the opposite beneficial effect. In addition, the CsA-induced up-regulated expression of TGF-beta1, PAI-1, and the matrix proteins biglycan, fibronectin, and collagen I was significantly increased with L-NAME and strikingly improved with L-Arg. Collagen IV expression was not affected. Also, NO modulation did not affect VH-treated rats. CONCLUSIONS: Chronic CsA nephrotoxicity can be aggravated by NO blockade and ameliorated by NO enhancement, suggesting that NO maintains a protective function. NO modulation was associated with a change in TGF-beta1 expression, which, in turn, was associated with alterations in matrix deposition and matrix degradation through its effect on PAI-1.  相似文献   
105.
颗粒细胞瘤(GranularCelTumor,GCT)是一种罕见的肿瘤。常发生于舌、皮肤及皮下组织、乳腺等部位。呼吸道GCT发生率低,若累及呼吸道则以喉和支气管较多见。原发部位位于气管的GCT极少,截止到1986年英文文献仅有10例气管GCT报道,国内近13年未有气管颗粒细胞瘤报道,。本文报道1例30岁女性气管GCT患者,结合文献对气管GCT的组织发生、临床表现、病理特点、诊断与鉴别诊断以及治疗方法等问题进行讨论。  相似文献   
106.
大鼠脑神经干细胞神经巢蛋白表达的流式细胞术检测   总被引:9,自引:1,他引:8  
检测胎鼠及成年大鼠脑内神经干细胞特异性抗原神经巢蛋白的表达,判明啮齿类哺乳动物脑内神经干细胞存在的可能性及相应的部位。方法:显微手术下采取胎鼠及成年大鼠大脑与皮质下脑组织,间接荧光法标记nestin,以流式细胞术检测。结果胎鼠脑内普遍存在nestin阳性细胞,成年大鼠脑室旁组织中也存在nestin阳性细胞。  相似文献   
107.
We have studied the mitogenic, motogenic and morphogenic effects of hepatocyte growth factor (HGF), also known as scatter factor (SF), on 15 non-small-cell lung carcinoma (NSCLC) cell lines that have had their ras genotype determined. HGF/SF stimulated proliferation in only three cell lines and exerted no mitogenic activity on six lines. The growth of the remaining six lines was inhibited. The mitogenic effects were not related to the ras genotype of these cell lines, but the inhibitory effect was more commonly observed in cell lines with relatively high levels of Met/HGF receptor (HGFR) expression. HGF/SF induced or enhanced both scatter activity on monolayer culture and single-cell invasion in collagen gels in approximately half of these cell lines. Although the ras genotype of tumour cells did not influence the HGF/SF-induced motogenic activity, cell lines with the mutant ras genotype more commonly demonstrated a spontaneous motogenic activity than those with the wild-type ras genotype. When tumour cells were grown in collagen gels, HGF/SF induced irregular branching extensions of cell aggregates formed by five out of eight adenocarcinoma cell lines, but significant lumen morphogenesis was distinctly absent. The presence of autocrine HGF/SF loop in these tumour cell lines did not influence their spontaneous or HGF/SF-induced mitogenic, motogenic or morphogenic activities. Overall, our data suggest that stimulation of cell motility, rather than proliferation or differentiation, is the predominant paracrine effect of HGF/SF on NSCLC cells in vitro.  相似文献   
108.
药品说明书是药品获批准上市后的重要证明文件之一,是对被批准的适应症、用法、用量等有关用药重要信息的详细说明,是指导医患用药的关键依据。在《中华人民共和国药品管理法》、《药品注册管理办法》(试行)以及国家食品药品监督管理局局23号令等法律、法规和条例中,对药品说明书及相关内容明确了其要求和责任等,这对认识说明书的作用和地位,并且对其进行制订和核准都起着重要的指导作用。  相似文献   
109.
CONTEXT: Despite advances in early detection and prevention of cervical cancer, women living in rural areas, and particularly in Appalachia, the rural South, the Texas/Mexico border, and the central valley of California, have had consistently higher rates of cervical cancer mortality than their counterparts in other areas during the past several decades. METHODS: This paper reviews the published literature from 1966 to July 2002 to assess three potential pathways underlying this excess mortality--high human papilloma virus (HPV) prevalence, lack of or infrequent screening and advanced disease at diagnosis, and under-use of recommended treatment and shorter survival. FINDINGS: Living in rural areas may impose barriers to cervical cancer control, including lack of transportation and medical care infrastructures. Population characteristics that place women at greater risk for developing and dying from cervical cancer, such as low income, lack of health insurance, and physician availability, are concentrated in rural areas. Published data, however, are insufficient to identify the key reasons for the observed mortality patterns. CONCLUSIONS: At this time, given the lack of definitive evidence in the published literature, decisions about priorities in areas with high rates of cervical cancer mortality will depend on knowledge of current levels of screening, incidence, and stage distribution; and service delivery infrastructures, resources, and acceptability of interventions to the target population.  相似文献   
110.
柴莪退热栓治疗急性病毒性上呼吸道感染临床研究   总被引:2,自引:1,他引:2  
目的观察柴莪退热栓治疗急性病毒性上呼吸道感染中医辨证属卫分证、卫气同病证的临床疗效,并探讨外感高热卫分证、卫气同病证证候与疗效间的关系.方法将患者 80例随机分为治疗组与对照组,分别予柴莪退热栓和消炎痛栓塞肛,并进行安全性评价.结果两组总体疗效相当,且未发现明显毒副作用.结论 柴莪退热栓治疗急性病毒性上呼吸道感染疗效满意.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号