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   1650096篇
  免费   134105篇
  国内免费   2616篇
耳鼻咽喉   22387篇
儿科学   54357篇
妇产科学   47367篇
基础医学   234847篇
口腔科学   49088篇
临床医学   145581篇
内科学   323141篇
皮肤病学   35303篇
神经病学   135242篇
特种医学   66960篇
外国民族医学   474篇
外科学   250475篇
综合类   39879篇
现状与发展   3篇
一般理论   571篇
预防医学   126130篇
眼科学   37505篇
药学   124628篇
  3篇
中国医学   3049篇
肿瘤学   89827篇
  2018年   15880篇
  2016年   14144篇
  2015年   15983篇
  2014年   21761篇
  2013年   33435篇
  2012年   45194篇
  2011年   47812篇
  2010年   27904篇
  2009年   26316篇
  2008年   46018篇
  2007年   48384篇
  2006年   48982篇
  2005年   47528篇
  2004年   46856篇
  2003年   44994篇
  2002年   44015篇
  2001年   77462篇
  2000年   80618篇
  1999年   67598篇
  1998年   18151篇
  1997年   16689篇
  1996年   16589篇
  1995年   16240篇
  1994年   15318篇
  1993年   14450篇
  1992年   55631篇
  1991年   53949篇
  1990年   52720篇
  1989年   51030篇
  1988年   47376篇
  1987年   46715篇
  1986年   44455篇
  1985年   43057篇
  1984年   32276篇
  1983年   27769篇
  1982年   16334篇
  1981年   14611篇
  1980年   13719篇
  1979年   30645篇
  1978年   21204篇
  1977年   17919篇
  1976年   16834篇
  1975年   17704篇
  1974年   21601篇
  1973年   20806篇
  1972年   18925篇
  1971年   17829篇
  1970年   16362篇
  1969年   15338篇
  1968年   14036篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction.  相似文献   
102.
103.
104.
105.
106.
We report a case of cervical necrotizing fasciitis (CNF) in a female having uncontrolled type II diabetes mellitus. The patient was presented to us after 20 days of preliminary symptoms. The aetiology of microbial inoculation in subdermal tissue was not known. The isolate was Staphylococcus aureus. In spite of the delay in presentation, the patient was successfully treated with combined antimicrobial and surgical intervention.  相似文献   
107.
Clinicopathological and electron microscopical findings of eight cases of enzootic nasal adenocarcinoma of sheep, diagnosed solely in one big flock in Slovenia between years 2001 and 2003 are described. All affected sheep were female, their mean age was 4.5 ± 1.5 years and they either belonged to the Istrian pramenka breed (five sheep) or were crossbreeds (three sheep). Tumours that arose from the ethmoid area of the nasal cavity were unilateral in six cases (75%) and bilateral in two cases (25%). All tumours were classified as adenocarcinomas by histopathological examination and they displayed either a combination of tubular and papillary growth or less often solely tubular proliferation. No metastases were detected in regional lymph nodes, brain or other organs. Electron microscopical studies performed on the reprocessed paraffin‐embedded tissues revealed the presence of the virus‐like particles with an average diameter between 70 and 90 nm.  相似文献   
108.
The influence of short‐term confinement and moderate exercise on tibia development was investigated in growing pigs (36–41 kg, 10 weeks at the beginning of the study). Animals were kept for 2 weeks either in individual crates of 0.8 m2 (‘confinement’, n = 4) or kept in groups of four animals in large crates of 5.6 m2 without (‘control’) or with additional exercise (30 min walking at 5 days/week; ‘exercise’). Bone density and morphological parameters were evaluated by computer tomography (CT). Periosteal apposition and longitudinal growth were determined after polychrome sequential labelling in weekly intervals. Cortical areas of the cross sections at the mid‐shaft and at 75% of the length of the bone measured distal to the carpus by CT were significantly correlated to each other (r = 0.70) and revealed a significant reduction in confined animals. This difference was explained by lower periosteal apposition rates in these animals compared with exercised and group‐housed pigs. Similarly longitudinal growth and the formation and calcification of spongiosa of the tibiae were inhibited by confinement. Thus, 2 weeks of confinement led to significant differences in bone growth and metabolism in young growing piglets when compared with animals with moderate activity.  相似文献   
109.
A 72-year-old man presented with a short duration of symptoms relating to a right fronto-parietal glioblastoma and a family history of children with brain tumours. Analysis of the patient's family tree revealed that out of seven children, he had a living son with anaplastic astrocytoma, a daughter who had died with a glioblastoma, and a son who had died with a histologically undiagnosed intrinsic brain tumour. One niece was also thought to have died from a brain tumour. All of the other affected family members had onset in their third or fourth decades. Tissue was only available from two of the affected individuals, precluding familial genetic analysis at this stage. There is no clinical evidence to support a diagnosis of a multiple cancer or neurocutaneous syndrome in this family. In view of what is known about the genetics of familial glioma, it is interesting to note the clinical evidence of both 'primary' glioblastoma and anaplastic astrocytoma in the same kindred.  相似文献   
110.
OBJECTIVE: Video-assisted thoracic surgery (VATS) is usually performed with general anesthesia and double-lumen endotracheal intubation, but minor procedures have been carried out with patients spontaneously breathing and with epidural or regional analgesia. We have broadened our indications for VATS utilizing purely local anesthesia and sedation. METHODS: The medical records of all patients undergoing VATS under local anesthesia and sedation at Geisinger Wyoming Valley Medical Center between 7/1/02 and 6/1/06 were reviewed. All procedures were performed in the operating room with patients in full lateral position; no patient had endotracheal intubation or epidural or nerve block analgesia. RESULTS: One hundred and fifteen patients, ranging in age from 21 to 88 years and in size from 40 to 172 kg, underwent 126 video-assisted thoracic operations: pleural biopsy/effusion drainage with or without talc 81, drainage of empyema 21, lung biopsy 18, evacuate hemothorax 3, pericardial window 2, biopsy chest wall mass 1. No patient required intubation or conversion to thoracotomy. Three patients who underwent lung biopsy died of their underlying disease (cytomegalovirus and pneumocystis, primary amyloidosis, metastatic cancer to contra-lateral lung) on postoperative days 18, 14, and 4, respectively. One patient developed transient renal insufficiency attributed to ketorolac. CONCLUSION: VATS utilizing local anesthesia and sedation is well tolerated, safe, and valuable for an increasing number of indications.  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