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   9071篇
  免费   627篇
  国内免费   23篇
耳鼻咽喉   43篇
儿科学   259篇
妇产科学   259篇
基础医学   1377篇
口腔科学   181篇
临床医学   1062篇
内科学   1763篇
皮肤病学   241篇
神经病学   1202篇
特种医学   221篇
外科学   736篇
综合类   70篇
一般理论   9篇
预防医学   824篇
眼科学   305篇
药学   571篇
中国医学   20篇
肿瘤学   578篇
  2023年   79篇
  2022年   119篇
  2021年   212篇
  2020年   190篇
  2019年   223篇
  2018年   275篇
  2017年   219篇
  2016年   226篇
  2015年   278篇
  2014年   306篇
  2013年   475篇
  2012年   755篇
  2011年   728篇
  2010年   383篇
  2009年   352篇
  2008年   654篇
  2007年   611篇
  2006年   561篇
  2005年   532篇
  2004年   492篇
  2003年   457篇
  2002年   446篇
  2001年   73篇
  2000年   44篇
  1999年   66篇
  1998年   86篇
  1997年   74篇
  1996年   68篇
  1995年   46篇
  1994年   52篇
  1993年   44篇
  1992年   38篇
  1991年   26篇
  1990年   22篇
  1989年   18篇
  1988年   26篇
  1987年   32篇
  1986年   31篇
  1985年   23篇
  1984年   26篇
  1983年   27篇
  1982年   25篇
  1981年   16篇
  1980年   20篇
  1978年   28篇
  1977年   16篇
  1976年   18篇
  1975年   17篇
  1971年   17篇
  1970年   18篇
排序方式: 共有9721条查询结果,搜索用时 93 毫秒
91.
92.
Summary A questionnaire survey was carried out to explore differences in the approach to treatment of patients with Type II diabetes between physicians in Northern Ireland, Norway and Sweden, and to discover to what extent it could account for the three-fold difference in drug use between the countries. A representative sample of 400 physicians in each country was asked to give their opinions on the choice of therapy for three model cases designed to cover the spectrum of treatment — from diet alone to insulin. Significantly more Swedish (65%) than Northern Irish (51%) and Norwegian (52%) doctors suggested diet alone for uncomplicated diabetes recently discovered in a middle aged, overweight man. For symptomatic diabetes in a 76 year old overweight woman with few retinal microaneurysms, the majority of physicians in all three countries suggested treatment with sulphonylureas. Biguanides were here a more common alternative in Northern Ireland than in Scandinavia. For suspected secondary treatment failure in a 63 year old woman with no signs of complications, insulin was suggested by 71% of the Norwegian doctors but only by 44 and 49% of those in Northern Ireland and Sweden, respectively. General practitioners tended to suggest oral treatment earlier and to maintain it longer than hospital physicians. The study has demonstrated significant differences in the approach to treatment of Type II diabetes mellitus between physicians in the three countries. However, the differences were more prominent in the choice of drugs than in the threshold of drug treatment. The results also fit with qualitative but not with quantitative differences in drug sales between the countries, suggesting that important differences may exist in the prevalence of clinically recognized Type II diabetes.  相似文献   
93.
Both the phytopathogenic fungus Ramularia collo-cygni and the hyperparasite R. uredinicola biosynthesize a number of red and yellow anthraquinone derivatives called rubellins. The new compounds uredinorubellins I and II, which were isolated from R. uredinicola, contribute to understanding the biosynthesis pathway that leads from simple anthraquinones to the rubellins. In addition, we isolated for the first time such simple compounds as chrysophanol and helminthsporin from both Ramularia species. A blue compound isolated from the mycelium of R. collo-cygni was revealed to be a unique 9,4-anthracenedione derivative. Structure elucidation by (1)H and (13)C NMR of the new but unstable compound caeruleoramularin was possible only by feeding the fungus different labeled (13)C acetates. The photodynamic activity of the uredinorubellins was comparable to rubellin D, whereas chrysophanol and caeruleoramularin did not display such activity.  相似文献   
94.
95.
96.
97.
98.
AIMS: To analyze diagnosis and treatment of four advanced abdominal pregnancies in a low-resource setting of a developing country. METHODS: Extrauterine pregnancies occurring between 1997 and 2003 were identified from hospital records of the Mikumi Health Center in Tanzania/East Africa. RESULTS: A total of 45 extrauterine pregnancies were diagnosed four of which were advanced and located in the abdominal cavity. At the time of diagnosis, pregnancies were at 33, 34, 36 and 39 weeks of gestation, respectively. All four mothers survived but three of four fetuses died. One child is alive and well three years after delivery. CONCLUSION: Abdominal pregnancy is rather difficult to detect in a low-resource setting of a developing country. Persistent abdominal pain and tenderness, as well as fetal movements in the upper abdomen associated with abnormal fetal lie, may lead to its diagnosis. Localizing the fetal heart sounds in the maternal epigastrium especially in patients with abdominal pain may also be helpful in diagnosing an abdominal pregnancy. In addition, the lack of cervical changes or a displaced cervix should lead to the suspicion of an abdominal pregnancy.  相似文献   
99.
100.
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