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   18363篇
  免费   912篇
  国内免费   143篇
耳鼻咽喉   213篇
儿科学   404篇
妇产科学   249篇
基础医学   2224篇
口腔科学   442篇
临床医学   995篇
内科学   4780篇
皮肤病学   659篇
神经病学   1522篇
特种医学   911篇
外科学   3174篇
综合类   94篇
一般理论   3篇
预防医学   397篇
眼科学   227篇
药学   1076篇
中国医学   39篇
肿瘤学   2009篇
  2023年   84篇
  2022年   174篇
  2021年   327篇
  2020年   218篇
  2019年   246篇
  2018年   338篇
  2017年   301篇
  2016年   385篇
  2015年   388篇
  2014年   529篇
  2013年   645篇
  2012年   901篇
  2011年   1013篇
  2010年   658篇
  2009年   555篇
  2008年   1028篇
  2007年   1097篇
  2006年   1107篇
  2005年   1154篇
  2004年   1034篇
  2003年   1013篇
  2002年   1058篇
  2001年   398篇
  2000年   338篇
  1999年   372篇
  1998年   322篇
  1997年   234篇
  1996年   252篇
  1995年   224篇
  1994年   183篇
  1993年   170篇
  1992年   269篇
  1991年   228篇
  1990年   254篇
  1989年   200篇
  1988年   188篇
  1987年   196篇
  1986年   158篇
  1985年   167篇
  1984年   133篇
  1983年   100篇
  1982年   67篇
  1981年   65篇
  1980年   73篇
  1979年   78篇
  1978年   50篇
  1977年   48篇
  1974年   46篇
  1972年   39篇
  1971年   40篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
101.
Clinical features such as types of diseases, sex ratio, age of onset, sites of initial involvement, the appearance of bulbar signs, and duration of illness were studied in 52 patients with motor neuron disease (MND) with a special reference to immunoglobulin in cerebrospinal fluid (CSF) and serum. Although MND has been thought to be a degenerative disease of unknown cause, our data suggested there are some immunological abnormalities in this disease. The duration of illness and the abnormalities of CSF immunoglobulins appeared to be correlated with the type of disease and the site of initial involvement. However, whether or not these abnormalities in CSF immunoglobulins are directly related to the pathogenesis of MND remains unclear.  相似文献   
102.
Optimal initial palliation and a subsequent staged approach is mandatory for high-risk Fontan candidates. We describe the case of mitral atresia with severe tricuspid regurgitation and pulmonary hypertension successfully managed by repeated palliation from the neonatal period and 2-stage Fontan surgery. A 1-month-old boy diagnosed with mitral atresia and double-outlet right ventricle underwent pulmonary artery banding at 1 month of age, followed by repeated pulmonary artery banding accompanied by tricuspid annuloplasty and atrial septal defect enlargement at 6 months. Because of the presence of pulmonary artery distortion, right ventricular dysfunction, and borderline pulmonary vascular resistance, a hemi-Fontan procedure was conducted with extended pulmonary artery plasty when the boy was 3 years and 8 months old. Cardiac catheterization done 3 months after showed improvement in risk factors, and the final Fontan operation (total cavopulmonary connection) was successfully done in conjunction with repeated tricuspid annuloplasty when the boy was 4 years and 5 months old. The patient remains in excellent clinical condition at the last follow-up 5 years after the final Fontan procedure with sinus rhythm and good ventricular function.  相似文献   
103.
104.
In order to determine the prevalence of allergic disorders and their association with agricultural factors, a total of 3,717 inhabitants of rural districts in Kumamoto Prefecture were ashed to fill out a questionnaire concerning their allergic status. The results obtained were as follows: One or more items of allergic symptoms were reported by 44% of the subjects. The prevalence rate of each symptom was 8% for respiratory organs, 5% for delayed type of respiratory disorders, 10% for nasal mucosa, 16% for eyes, 16% for urticaria-like derma and 26% for eczema-like derma. Twenty-one percent of the subjects had past histories of allergic diseases such as asthma (3%), nasal allergy (3%), urticaria (6%), contact dermatitis (9%) and so forth. These allergic conditions were seen to be more common among farmers than non-agricultural workers, and also among subjects with allergic constitution than those without such constitution. The highest (62%) prevalence of allergic symptoms was observed in farmers engaged in poultry raising, followed by those engaged in raising flowers (58%), tobacco (58%), cortinellus shiitake (55%), cucumber in plastic greenhouse (53%) and mandarin orange (53%). Among the symptomatic subjects, 12-38% of those with each symptom gave farm work as the direct causative factor for developing the corresponding symptom. Pesticide spraying was the most common agent among those factors.  相似文献   
105.
The in vitro clonogenic assay has been used to assess the biological effects of estradiol-17 beta (E 2) and an antiestrogen, tamoxifen (TAM) on human breast cancer, and the results were compared with the estrogen receptor status (ER). The sera used were treated with dextran-coated charcoal to avoid the modification effects of the endogenous hormones. There was a significant difference between ER (+) and ER (-) breast cancers in the incidence of cases in which the plating efficiency of cancers increased more than 50% over those of untreated control by adding 10(-8) M of E 2 (40.2% vs. 21.3%). TAM, 10(-6) M revealed a less than 50% colony formation of the control in 30.5% of ER (+) cancers, whereas only 13.0% of ER (-) cancers showed a response to TAM.  相似文献   
106.
Glutathione transferase P (GST-P; glutathione transferase, EC 2.5.1.18) is known to be specifically expressed at high levels in precancerous lesions and in hepatocellular carcinomas from a very early phase of chemically induced hepatocarcinogenesis in the rat. The almost invariable occurrence of this phenotype in these lesions strongly suggests a mechanism by which GST-P gene is activated together with a crucial transforming gene of liver cells. To distinguish the two alternative possibilities--either the GST-P gene is coactivated with a closely located transforming gene by a cis mechanism or it is activated in trans by a common trans-acting factor--we carried out carcinogenesis experiments using transgenic rats harboring the bacterial chloramphenicol acetyltransferase reporter gene ligated to the upstream regulatory sequence of the GST-P gene. In each of three independent lines tested, liver foci and nodules produced by chemical carcinogens (Solt-Farber procedure) were found to express high levels of chloramphenicol acetyltransferase activity, indicating clearly that the GST-P gene is activated by a trans mechanism during hepatocarcinogenesis.  相似文献   
107.
108.
109.
We reported a case of the biliary cystadenoma of the liver. The cystic mass had labulation and septation and showed marked hyperintensity on T1-weighted images and hypointensity on T2-weighted images; MR findings were very unusual for cystadenoma. The content of the cystic mass was jelly-like, thick mucinous fluid without intracystic hemorrhage. We concluded that these unusual signal intensities of the cyst were due to hyperproteinous mucinous fluid.  相似文献   
110.
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