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   1710329篇
  免费   121214篇
  国内免费   3420篇
耳鼻咽喉   24299篇
儿科学   49935篇
妇产科学   46481篇
基础医学   242376篇
口腔科学   50000篇
临床医学   145667篇
内科学   340069篇
皮肤病学   36023篇
神经病学   134148篇
特种医学   68135篇
外国民族医学   411篇
外科学   274409篇
综合类   34714篇
现状与发展   1篇
一般理论   469篇
预防医学   119140篇
眼科学   39204篇
药学   127397篇
  3篇
中国医学   3670篇
肿瘤学   98412篇
  2018年   16635篇
  2017年   13105篇
  2016年   14249篇
  2015年   16213篇
  2014年   22601篇
  2013年   34203篇
  2012年   46192篇
  2011年   48702篇
  2010年   29253篇
  2009年   28023篇
  2008年   47384篇
  2007年   49792篇
  2006年   50731篇
  2005年   49350篇
  2004年   47495篇
  2003年   45822篇
  2002年   45053篇
  2001年   88319篇
  2000年   91177篇
  1999年   76771篇
  1998年   19382篇
  1997年   17430篇
  1996年   17382篇
  1995年   16199篇
  1994年   15308篇
  1993年   14190篇
  1992年   59099篇
  1991年   56629篇
  1990年   55010篇
  1989年   53374篇
  1988年   48956篇
  1987年   48075篇
  1986年   45329篇
  1985年   43280篇
  1984年   31517篇
  1983年   26776篇
  1982年   14921篇
  1981年   13054篇
  1979年   28587篇
  1978年   19617篇
  1977年   16710篇
  1976年   15114篇
  1975年   16659篇
  1974年   20107篇
  1973年   19036篇
  1972年   18107篇
  1971年   16902篇
  1970年   16264篇
  1969年   15239篇
  1968年   14178篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
CT evaluation of Crohn's disease: effect on patient management   总被引:8,自引:0,他引:8  
CT scans from 80 consecutive patients with clinically symptomatic Crohn's disease were reviewed retrospectively to determine the effect of CT diagnosis on patient management. The initial clinical impression and any subsequent change in patient management because of the CT findings were noted. In 22 (28%) of the 80 patients, significant previously unsuspected findings led to a change in medical or surgical management. These included 12 patients with fistulae, four with abscess, two with avascular necrosis of the femoral head, two with sacral osteomyelitis, and single cases of pelvic inflammatory disease and femoral vein thrombosis.  相似文献   
992.
We report an 80-year-old Japanese male with four primary malignant tumors: malignant melanoma, prostatic cancer, malignant lymphoma, and renal cell carcinoma, which occurred in that respective order. The combination of malignant melanoma and malignant lymphoma is rare. The patient was treated with BCG after an operation for malignant melanoma. He was also treated with cobalt 60 irradiation after an operation for prostatic cancer. We also discuss other reports of multiple malignant tumors and suggest some possible causes of this patient's primary malignant tumors.  相似文献   
993.
A prospective study of 20 normal subjects was undertaken to determine the effect of three ankle positions (active dorsiflexion, active plantar flexion, natural or rest position) on comfort and facilitation of quadriceps contraction in isometric strengthening in a supine position with the hip and knee fully extended. Surface EMG activity was found to be greatest for the vastus lateralis followed by the vastus medialis and least for the rectus femoris. Equal facilitation was apparent with either active ankle dorsiflexion or plantar flexion. Both were superior to the natural (rest) position. In situations where isometric quadriceps exercises are required, the authors recommend either active ankle dorsiflexion or plantar flexion to facilitate quadriceps strengthening. The choice between the two positions should be based on patient comfort.  相似文献   
994.
Specific pathogen-free rats were exposed to the cigarette smoke (CS) of 25 cigarettes daily for 14 days and concurrently given N-acetylcysteine (Nac) as 1% of their drinking water (average daily dose 973 mg/kg). The thickness of the epithelium was measured at four airway levels and the numbers of mucus-containing secretory cells, stained for neutral or acidic glycoprotein (NGP or AGP respectively), were counted in surface epithelium at eight airway levels. Cigarette smoke increased the thickness of the epithelium at three of the airway levels studied by between 37 and 72%. The number of secretory cells was increased at all airway levels distal to the upper trachea by between 102 and 421%. Secretory cells containing NGP were reduced in number but this was more than offset by a large increase in the number of secretory cells containing AGP at all airway levels. N-acetylcysteine inhibited CS-induced epithelial thickening. Nac also inhibited the CS-induced increase in the number of secretory cells with AGP, but had little effect on the CS-induced reduction in the number of cells with NGP. Thus, prophylactic oral N-acetylcysteine led to an overall inhibition of CS-induced mucous cell hyperplasia and epithelial hypertrophy. The results suggest a novel anti-inflammatory action for a drug with known mucolytic effects.  相似文献   
995.
996.
997.
Isolated abnormalities of pursuit gaze were studied in 8 patients with unilateral acute (hemorrhage) or chronic (tumor) lesions of the parieto-occipital lobes. Ipsilateral pursuit was impaired in all patients, being superimposed with cogwheel saccades. Foveal pursuit was more disturbed than full-field pursuit. Impairment of contralateral pursuit was observed in all patients, but was severe only after acute involvement of the nondominant hemisphere. These findings provide further evidence for some asymmetric organization of hemispheric command of ocular movements. In these patients with hemianopia, the bilateral alterations of pursuit gaze probably correspond to an inter- and intrahemispheric disconnection syndrome.  相似文献   
998.
999.
We report a 3-year-old girl with hereditary motor and sensory neuropathy type III with a decrease in unmyelinated fibers. There have been few reports of such cases. The present findings suggest the possibility that the primary lesion in this disease is in the axons. We consider that more attention should be paid to the changes in unmyelinated fibers and axons in further studies on this disease.  相似文献   
1000.
Sex and racial predilection, social history, and histology were analyzed in a biopsy-proven adenocarcinoma of the lower esophagus/esophagogastric junction collected over a 5-year period in two teaching institutions with different patient populations. Adenocarcinoma occurred in 11% of patients with biopsy-proven esophageal cancer. The disease occurred only in males at one center, and in a 7:1 ratio of males to females at the other center. Clear racial predilection was seen, since 12 of 13 patients with adenocarcinoma of the esophagus were white, whereas less than 20% of patients with squamous carcinoma of the esophagus were white. The finding of Barrett's epithelium in eight of the 13 cases strongly supports the theory that in white males, Barrett's epithelium is a precursor lesion of adenocarcinoma of the esophagus/esophagogastric junction.  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