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   4924803篇
  免费   393001篇
  国内免费   15572篇
耳鼻咽喉   69165篇
儿科学   158094篇
妇产科学   130070篇
基础医学   740939篇
口腔科学   137183篇
临床医学   453618篇
内科学   900022篇
皮肤病学   117089篇
神经病学   413329篇
特种医学   193433篇
外国民族医学   968篇
外科学   740194篇
综合类   138929篇
现状与发展   24篇
一般理论   2809篇
预防医学   410665篇
眼科学   115718篇
药学   351714篇
  23篇
中国医学   12993篇
肿瘤学   246397篇
  2021年   56898篇
  2019年   59340篇
  2018年   76169篇
  2017年   58082篇
  2016年   64468篇
  2015年   76920篇
  2014年   111384篇
  2013年   177120篇
  2012年   140245篇
  2011年   148176篇
  2010年   130974篇
  2009年   130967篇
  2008年   133494篇
  2007年   143357篇
  2006年   150918篇
  2005年   145158篇
  2004年   145933篇
  2003年   135780篇
  2002年   124409篇
  2001年   197254篇
  2000年   194210篇
  1999年   174304篇
  1998年   75862篇
  1997年   70575篇
  1996年   68758篇
  1995年   64336篇
  1994年   58175篇
  1993年   54002篇
  1992年   128568篇
  1991年   123378篇
  1990年   118820篇
  1989年   115364篇
  1988年   106262篇
  1987年   104319篇
  1986年   98411篇
  1985年   95828篇
  1984年   77788篇
  1983年   68459篇
  1982年   51627篇
  1981年   47709篇
  1980年   44728篇
  1979年   67692篇
  1978年   53043篇
  1977年   46614篇
  1976年   43241篇
  1975年   44063篇
  1974年   48991篇
  1973年   46933篇
  1972年   43930篇
  1971年   40621篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
113.
Secondary tricuspid regurgitation (TR) caused by right ventricular enlargement in the setting of left heart disease/pulmonary hypertension has been well described. In contrast, that associated with right atrial enlargement—atrial functional TR (AF‐TR)—remains largely underappreciated. AF‐TR most often occurs in the setting of lone atrial fibrillation, although it is also seen in its absence (idiopathic AF‐TR). Several recent studies have found that the prevalence, hemodynamic significance, and prognosis of AF‐TR are not inconsequential, suggesting increased physician awareness of this novel clinical entity is warranted. This article discusses the pathogenesis, echocardiographic findings, and treatment of this underappreciated cause of secondary TR.  相似文献   
114.
We review the spectrum of cutaneous disorders associated with inflammatory and neoplastic plasmacytic pathology. Because plasma cells are derived from B‐lymphocytes our overview includes discussion of certain lymphoplasmacytic proliferations. It is structured along histopathological lines, addressing conditions characterized by (a) cutaneous plasma cell infiltrates, (b) deposits of plasma cell products or their derivatives in the skin and (c) miscellaneous, poorly understood cutaneous complications of plasmacytic disorders. Lesions arising primarily in the skin and those due to cutaneous involvement by multisystem disorders are addressed. The range includes a spectrum of tumefactive and circulatory manifestations. We highlight key clinical and pathological features of the different conditions and outline recent advances in our understanding of these entities. By emphasizing the dermatopathological characteristics of this spectrum of disorders we hope to hone the diagnostic accuracy of practitioners in the field.  相似文献   
115.
116.
BackgroundThe aim of this study was to estimate the prevalence of dental prosthetic treatment and to investigate the demographic, social, economic and medical factors associated with the use of fixed and removable dentures in a representative sample of adults living in France.MethodsThe data were obtained from the 2002–2003 Decennial Health Survey, a cross-sectional study of a representative sample of the population living in France, which included 29,679 adults. Information was collected by interview. The variables collected were fixed denture, removable denture, age, gender, number of children, area of residence, nationality, educational attainment, family social status, employment status, annual household income per capita, supplementary insurance, chronic disease, eyesight problems/glasses, hearing problems/hearing aids. Multinomial logistic regression models were used to study the relationship between prosthetic treatment and demographic, socioeconomic and medical characteristics unadjusted, adjusted for age and adjusted for all the characteristics.ResultsThe prevalence of prosthetic treatment was 34.6% (95% confidence interval (CI): [34.1; 35.2]) for fixed prosthetic dentures and 13.8% (95% CI: [13.4; 14.2]) for removable prosthetic dentures. We showed a gradient between educational attainment and removable dentures; the odds ratio adjusted for all the variables (aOR) associated with no or primary education compared to post-secondary education was 2.56; 95% CI: [2.09; 3.13]. When annual household income per capita was low, subjects were less likely to report fixed dentures (aOR = 0.68; 95% CI: [0.62; 0.75]) than those with high annual household income per capita. Individuals without insurance less often reported fixed dentures than those with private insurance. Those reporting chronic disease were less likely to report fixed dentures (aOR = 0.87; 95% CI: [0.79; 0.95]) but more likely to report removable dentures (aOR = 1.29; 95% CI: [1.17; 1.43]) than those without chronic disease.ConclusionThis study reveals social, economic and medical inequalities in fixed and removable prosthetic treatment among adults in France.  相似文献   
117.
  1. The common marmoset (Callithrix jacchus) is a useful experimental animal to evaluate the pharmacokinetics of drug candidates. Cytochrome P450 (P450) 2B enzyme in marmoset livers has been identified; however, only limited information on the enzymatic properties and distribution has been available.

  2. Marmoset P450 2B6 amino acids showed high sequence identities (>86%) with those of primates including humans and cynomolgus monkeys. Phylogenetic analysis using amino acid sequences indicated that marmoset P450 2B6 was closer to human and cynomolgus monkey P450 2B6 than to P450 2B orthologs of other species, including pigs, dogs, rabbits and rodents.

  3. Quantitative polymerase chain reaction analysis using specific primers showed P450 2B6 mRNA predominantly expressed in livers among the five marmoset tissues, similar to those of humans and cynomolgus monkeys.

  4. Marmoset P450 2B6 heterologously expressed in Escherichia coli membranes oxidized 7-ethoxycoumarin, pentoxyresorufin, propofol and testosterone, at roughly similar rates to those of humans and/or cynomolgus monkeys. A high capacity of marmoset P450 2B6 with propofol 4-hydroxylation (at low ionic strength conditions) with a low Km value was relatively comparable to that for marmoset livers.

  5. These results collectively indicated a high propofol 4-hydroxylation activity of P450 2B6 expressed in marmoset livers.

  相似文献   
118.
119.
120.
Introduction: Pharmacovigilance is essential to monitoring the safety profiles of authorized medicines. Compared with small-molecule drugs, biological drugs are more complex, more susceptible to structural variability due to manufacturing processes, and have the potential to induce immune-related reactions, underscoring the importance of safety monitoring for these products. Although highly similar to reference products, biosimilars are not expected to be structurally identical. For these reasons, proper reporting of potential adverse drug reactions (ADRs) using distinguishable names and batch numbers is essential for accurate tracing of all biological drugs. To address the need for robust pharmacovigilance, the European Parliament and Council of the European Union provided legislation regarding pharmacovigilance of biologics in 2010.

Areas covered: This narrative review examines the current state of pharmacovigilance for biologics in the European Union (EU) and discusses relevant information on pharmacovigilance of biosimilars, the current EU pharmacovigilance system, and areas that could be improved.

Expert opinion: Although steps have been taken to improve pharmacovigilance of biologics in the EU, several enhancements can still be made, including additional training for healthcare professionals on ADR reporting, the use of 2D barcodes that enhance traceability, and an open discussion of potentially missed opportunities in the pharmacovigilance of biosimilars.  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