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   2097762篇
  免费   165794篇
  国内免费   7300篇
耳鼻咽喉   27792篇
儿科学   62869篇
妇产科学   55764篇
基础医学   291123篇
口腔科学   60695篇
临床医学   186899篇
内科学   423701篇
皮肤病学   47876篇
神经病学   169190篇
特种医学   85035篇
外国民族医学   346篇
外科学   334704篇
综合类   46253篇
现状与发展   3篇
一般理论   627篇
预防医学   157441篇
眼科学   45869篇
药学   154050篇
  8篇
中国医学   4050篇
肿瘤学   116561篇
  2018年   20431篇
  2016年   18846篇
  2015年   21201篇
  2014年   29371篇
  2013年   43773篇
  2012年   55517篇
  2011年   59137篇
  2010年   36323篇
  2009年   35302篇
  2008年   56195篇
  2007年   59656篇
  2006年   61310篇
  2005年   59217篇
  2004年   56713篇
  2003年   55075篇
  2002年   52991篇
  2001年   109076篇
  2000年   112616篇
  1999年   94051篇
  1998年   25602篇
  1997年   22625篇
  1996年   23595篇
  1995年   23160篇
  1994年   21563篇
  1993年   20089篇
  1992年   75489篇
  1991年   73041篇
  1990年   70514篇
  1989年   67834篇
  1988年   62559篇
  1987年   61170篇
  1986年   57517篇
  1985年   55404篇
  1984年   41053篇
  1983年   34729篇
  1982年   20206篇
  1981年   17912篇
  1980年   16792篇
  1979年   36764篇
  1978年   25857篇
  1977年   21972篇
  1976年   19780篇
  1975年   21057篇
  1974年   25013篇
  1973年   23809篇
  1972年   22304篇
  1971年   20763篇
  1970年   19253篇
  1969年   18032篇
  1968年   16638篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
51.
Pediatric trachyonychia is an acquired nail disease that can cause distress to families. It is a poorly understood disease, and long‐term follow‐up data are lacking. We present an institutional review of 11 children with isolated pediatric trachyonychia followed over time. Children with the diagnosis of pediatric trachyonychia were identified and invited to participate. Pictures were taken on follow‐up and a questionnaire was answered. Exclusion criteria include having another diagnosis at the initial visit that causes nail dystrophy. Eleven patients with the diagnosis of pediatric trachyonychia were available for follow‐up. The mean age of appearance was 2.7 years (range 2–7 yrs) and the average follow‐up was 66 months (range 10–126 mos). Nine patients were treated with potent topical corticosteroids, one used only petrolatum, and one took vitamin supplements. One patient was found to have an additional skin and hair diagnosis of alopecia areata on follow‐up. On follow‐up, 82% noted improvement of the nails, whereas 18% noted no change. A majority of cases of pediatric trachyonychia are isolated and improve with time, regardless of treatment.  相似文献   
52.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
53.
54.
Bipolar disorder (BD) is a common psychiatric mood disorder affecting more than 1-2% of the general population of different European countries. Unfortunately, there is no objective laboratory-based test to aid BD diagnosis or monitor its progression, and little is known about the molecular basis of BD. Here, we performed a comparative proteomic study to identify differentially expressed plasma proteins in various BD mood states (depressed BD, manic BD, and euthymic BD) relative to healthy controls. A total of 10 euthymic BD, 20 depressed BD, 15 manic BD, and 20 demographically matched healthy control subjects were recruited. Seven high-abundance proteins were immunodepleted in plasma samples from the 4 experimental groups, which were then subjected to proteome-wide expression profiling by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight tandem mass spectrometry. Proteomic results were validated by immunoblotting and bioinformatically analyzed using MetaCore. From a total of 32 proteins identified with 1.5-fold changes in expression compared with healthy controls, 16 proteins were perturbed in BD independent of mood state, while 16 proteins were specifically associated with particular BD mood states. Two mood-independent differential proteins, apolipoprotein (Apo) A1 and Apo L1, suggest that BD pathophysiology may be associated with early perturbations in lipid metabolism. Moreover, down-regulation of one mood-dependent protein, carbonic anhydrase 1 (CA-1), suggests it may be involved in the pathophysiology of depressive episodes in BD. Thus, BD pathophysiology may be associated with early perturbations in lipid metabolism that are independent of mood state, while CA-1 may be involved in the pathophysiology of depressive episodes.  相似文献   
55.
56.
57.
58.
59.
60.
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