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   53547篇
  免费   3524篇
  国内免费   1577篇
耳鼻咽喉   625篇
儿科学   638篇
妇产科学   1087篇
基础医学   8253篇
口腔科学   1415篇
临床医学   4397篇
内科学   10181篇
皮肤病学   1002篇
神经病学   3804篇
特种医学   1733篇
外国民族医学   6篇
外科学   7336篇
综合类   3974篇
现状与发展   1篇
一般理论   5篇
预防医学   2979篇
眼科学   1376篇
药学   4730篇
  1篇
中国医学   758篇
肿瘤学   4347篇
  2023年   208篇
  2022年   325篇
  2021年   556篇
  2020年   376篇
  2019年   656篇
  2018年   1129篇
  2017年   907篇
  2016年   906篇
  2015年   977篇
  2014年   1294篇
  2013年   1586篇
  2012年   2163篇
  2011年   2095篇
  2010年   1270篇
  2009年   1245篇
  2008年   1852篇
  2007年   1960篇
  2006年   1825篇
  2005年   1513篇
  2004年   1379篇
  2003年   1340篇
  2002年   1275篇
  2001年   4639篇
  2000年   4551篇
  1999年   3911篇
  1998年   1375篇
  1997年   998篇
  1996年   611篇
  1995年   500篇
  1994年   452篇
  1993年   413篇
  1992年   1936篇
  1991年   1677篇
  1990年   1529篇
  1989年   1491篇
  1988年   1301篇
  1987年   1198篇
  1986年   1073篇
  1985年   901篇
  1984年   591篇
  1983年   468篇
  1982年   250篇
  1981年   180篇
  1980年   141篇
  1979年   282篇
  1978年   77篇
  1974年   75篇
  1973年   95篇
  1972年   71篇
  1969年   66篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
We describe the clinical course of 120 children with tricuspid atresia (TA) attended in the Hospital de Cardiología y Neumología, "Dr. Luis Méndez", del Centro Médico Nacional. There were 61 males and 59 females. The age of presentation was in 79 newborn babies, seventeen between one and six months old, 20 between six and 24 months old, and four with two or more years old. The clinical picture was hypoxic spells in 89% and congestive heart failure in the others. The chest film showed cardiomegaly in 85%, with diminished pulmonary flow in 48%, increased flow in 27.5%, and normal in 9%. The electrocardiogram with superior left axis deviation in 94%, right atrial hypertrophy in 58%, left atrial hypertrophy in 47.5% and left ventricular hypertrophy in 96%. TA was classified as type I in 103 children, type Ic in 70, Ib in 27 and Ia in six, and type II in seventeen children, with eight IIc, six IIb and three IIa. In 44 the management was medical, 63 underwent systemic-pulmonary anastomosis, 37 of them with Blalock-Taussig shunt and Fontan procedure in thirteen children. There were 21 deaths. This survey is compared with the literature and from this point we make management recommendations.  相似文献   
992.
Lian-Niang L  Hong X 《Planta medica》1986,52(6):493-494
A new tetrahydrofuran lignan, named henricine ( 1), was isolated from the stems of SCHISANDRA HENRYI. High resolution COSY spectrum was used in the structural elucidation.  相似文献   
993.
"Spontaneous" remission of leukemia has been observed in both humans and animals. Bierman et al2 in 1953 reported 11 cases of remis- sion in acute lymphoblastic leukemia (ALL) of childhood following acute infectious disease. In 1979 we saw a case of ALL remission in a child following a severe attack of respiratory infection.  相似文献   
994.
995.
Multiple sclerosis and childhood infections   总被引:1,自引:0,他引:1  
Migration from an area where MS is common to an area where it is rare (and vice versa) affects the risk of MS, provided migration occurs in childhood. A childhood infection might explain this effect. Therefore, the age pattern of infectious diseases in different regions was examined. A higher proportion of children showed positive titers to many viral diseases early in life in areas where MS is rare compared with those where MS is common. Also, mortality rates from a variety of infectious diseases correlated negatively with the MS mortality. Thus, infection early in life may "protect" against MS, and conversely, later infection, when the immune system has partially matured, may increase risk. MS may be an age-dependent, host-immune response to childhood infection.  相似文献   
996.
We administered a 17-item symptom questionnaire modified from Campbell to 155 patients with fibrositis diagnosed at 3 centers, each using different criteria sets. A high degree of agreement in symptom proportions was found among centers. "Fibrositic" symptoms were also common in 136 patients with a variety of rheumatic diseases but not in the 58 normal individuals studied. Symptoms distinguished fibrositis patients from normals easily, but had insufficient specificity to distinguish them from other rheumatic disease patients. The tender point count better separated fibrositic and nonfibrositic patients than historical criteria. No combination of questions and tender point count performed better than the tender point count alone.  相似文献   
997.
998.
Summary An 8-month-old girl had an ependymoma in the clivus, 2x6 cm in size, connected with the fourth ventricle by a cord of tissue 0.5 cm thick. There were no indications to make us suspect the origin of the tumour in the fourth ventricle, or that it was a case of ependymoma.  相似文献   
999.
Atypical antipsychotics are often addressed as one class of drugs, although there are marked differences in their pharmacological profiles. It is unknown how this is seen by practitioners and to what extent they differentiate between the various atypical compounds. In a drug utilization study, 472 schizophrenic outpatients who were switched for individual reasons from either olanzapine or risperidone to amisulpride were monitored. Data on patients, illness and treatment as well as on reasons to switch were collected. The reasons to switch from olanzapine to amisulpride were preferably 'weight gain' (72.6% of the physicians), or the 'expectancy of less weight gain with amisulpride' (84.1%) and 'patient request' (60.2%). Specific reasons to switch from risperidone were 'extrapyramidal symptoms' (58.5%), or the 'expectancy of few extrapyramidal symptoms with amisulpride' (82.5%). In conclusion, this study confirms that physicians do not consider 'atypical antipsychotics' as one homogeneous class of drugs but make differences that reflect the specific pharmacological profiles of the respective drugs.  相似文献   
1000.
BACKGROUND: Evolution of bowel habit in irritable bowel syndrome (IBS) is not well known. AIM: To evaluate the change over time of bowel habit in IBS patients followed-up during 1 year. METHODS: Five hundred and seventeen patients with IBS were prospectively included in an observational study with five evaluations over a 1-year period. Symptoms were recorded daily in diary cards during four 4-week periods along the study. Bristol Stool Scale (BSS) was used to define bowel habit. RESULTS: Four-hundred patients completed the study. Rome II showed low-moderate agreement (42%) with BSS to define bowel habit. Frequency of constipation and diarrhoea showed little changes throughout the study. Over 50% of the patients had the same bowel habit when each diary was compared with the next one. A third of patients maintained the same habit throughout the study. Most changes occurred from/to mixed or unsubtyped IBS. Only 14% of cases changed from constipation to diarrhoea or vice versa. This change was associated to female gender (OR: 2.65). CONCLUSIONS: The frequency of constipation and diarrhoea remains relatively stable over time. Changes in IBS subtypes are common, but changes between constipation and diarrhoea are rare. Alternating IBS is more frequent in women.  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