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   1336914篇
  免费   94388篇
  国内免费   2916篇
耳鼻咽喉   19724篇
儿科学   40247篇
妇产科学   38680篇
基础医学   187304篇
口腔科学   39884篇
临床医学   112701篇
内科学   262581篇
皮肤病学   30222篇
神经病学   106495篇
特种医学   53679篇
外国民族医学   435篇
外科学   208410篇
综合类   31046篇
现状与发展   6篇
一般理论   436篇
预防医学   92056篇
眼科学   31370篇
药学   100229篇
  4篇
中国医学   2990篇
肿瘤学   75719篇
  2018年   11761篇
  2015年   11887篇
  2014年   16715篇
  2013年   25284篇
  2012年   33050篇
  2011年   34924篇
  2010年   20761篇
  2009年   20252篇
  2008年   33615篇
  2007年   36744篇
  2006年   37302篇
  2005年   36077篇
  2004年   35122篇
  2003年   34116篇
  2002年   33656篇
  2001年   63640篇
  2000年   65361篇
  1999年   55410篇
  1998年   14668篇
  1997年   13476篇
  1996年   12949篇
  1995年   12231篇
  1994年   11474篇
  1992年   42803篇
  1991年   41306篇
  1990年   40584篇
  1989年   39563篇
  1988年   36980篇
  1987年   36420篇
  1986年   34910篇
  1985年   33120篇
  1984年   24834篇
  1983年   21067篇
  1982年   12664篇
  1981年   11569篇
  1980年   10773篇
  1979年   23927篇
  1978年   17070篇
  1977年   14839篇
  1976年   13386篇
  1975年   15271篇
  1974年   18082篇
  1973年   17567篇
  1972年   16816篇
  1971年   15720篇
  1970年   14917篇
  1969年   14346篇
  1968年   13464篇
  1967年   12016篇
  1966年   11260篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
181.
Carotid sonography is being performed on more than 5,000 participants in the Cardiovascular Health Study, a prospective, multicenter study of cardiovascular disease in men and women aged 65 years and older. The sonographic methods used to examine and measure the extracranial carotid arteries are described. Initial validation studies were performed on 61 subjects with a mean age of 68.6 years. Analysis of within- and between-sonographer differences and between-reader differences were performed for selected variables. In general, the mean absolute differences for within- and between-sonographer comparisons were small, with even less variability between readers. Variability was less for the common carotid artery than for the internal carotid artery. These data suggest that carotid sonography is a reliable and reproducible method for use in the study of carotid atherosclerosis in population studies.  相似文献   
182.
A 43-year-old woman suffered a blast-type injury to the head and neck. She subsequently developed bilateral internal carotid artery occlusion and bilateral anterior cerebral artery infarction not demonstrated by magnetic resonance imaging scan 24 hours after the explosion, but confirmed by a second scan 8 days after the explosion. In patients with blast-type injury to the head and neck who develop coma with a nonfocal neurological exam, the possibility of bilateral carotid artery occlusion and bilateral ischemic infarction should be considered.  相似文献   
183.
Vitamin B12 absorption and malabsorption.   总被引:1,自引:0,他引:1       下载免费PDF全文
H Schjnsby 《Gut》1989,30(12):1686-1691
  相似文献   
184.
A binding site for tritiated 2-amino-6, 7-dihydroxy-1, 2,3,4-tetrahydronaphthalene (ADTN) has been partially characterized in the rabbit iris root-ciliary body. Binding of ADTN is proportional to protein content and requires at least 60 minutes to reach equilibrium. Binding is saturable, with a Kd of 27 +/- 1 nM and a Bmax of 2.1 +/- .3 pmol/mg protein (mean +/- SEM). Dopamine competes for this site with a Ki of 100 nM and apomorphine with a Ki of 180 nM. This site is not blocked by L-timolol, phenoxybenzamine, or by several DA1 and DA2 antagonists. It appears to be a new type of catecholamine binding site, of a type not observed outside the anterior eye. It is possible that some of the effects of dopamine on intraocular pressure are mediated through this binding site.  相似文献   
185.
We report two patients with severe hypoglycorrhachia after a subarachnoid hemorrhage. They had no obvious meningeal infection, and they spontaneously recovered within a few weeks. Such cases have previously been reported in neonates, but exceptionally in adults. Contrary to detailed cases from the literature, our patients recovered without antibiotics, and hypoglycorrhachia was very severe.  相似文献   
186.
187.
In 1985, we initiated a prospective clinical trial to evaluate the risk of recurrence for superficial bladder cancer. Up to now, 41 patients subjected to TUR have subsequently been monitored by immunocytology with a monoclonal antibody (mab 486 p) recently developed in our laboratory. Of these patients, 15 (36.6%) remained marker-negative and received no prophylactic therapy. There was only one recurrence (6.7%) in this subset of patients, whereas 10 out of 26 (38.5%) marker-positive patients have so far developed recurrent malignancies. In all cases, the conversion of immunocytological characteristics preceded visible recurrence by 2-5 months. These preliminary results indicate that immunocytology might make it possible to identify patients at low risk of recurrence more accurately than has so far been feasible with standard cytology or flow-cytometry.  相似文献   
188.
There is increasing evidence from human and experimental studies that the most important factor governing the outcome in head injury is the severity of diffuse axonal injuries. The authors have experienced 18 cases of severe diffuse axonal injury which showed post-traumatic coma for more than 24 hours and CT findings resembling those of shearing injuries of the cerebral white matter such as have been presented by Zimmerman et al. (1978). The consciousness levels on admission were 6 or less on the Glasgow Coma Scale and all cases were shown clinically to have primary brain stem injury. The main type of head trauma resulted from road traffic accidents (83%). Skull fractures were found in only 5 cases (28%). These findings suggested that acceleration/deceleration injury produce in the patients severe diffuse axonal injury. Initial ICP was below 20 mmHg in 11 cases out of 13 (85%). Parenchymal small hemorrhagic lesions of initial CT were basal ganglia (7 cases), corpus callosum (4 cases), pons (4 cases), midbrain (3 cases) and thalamus (2 cases). Extraparenchymal hemorrhagic lesions included intraventricular hemorrhage (6 cases) and subarachnoid hemorrhage (6 cases). Two autopsied cases of severe diffuse axonal injury (acute case and chronic case) showed remarkable congestion and edema in the deep part of the frontal white matter. Microscopic examination revealed marked axonal degeneration including axonal retraction ball in the corpus callosum, in the internal capsule and in the white matter of the brain stem. Glasgow Outcome Scale of the 18 patients at 3 months after the trauma made us concerned that no patients indicated good recovery or even only moderate disability.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
189.
H Sasaki  K Sudoh  K Hamada  T Hamada  K Tashiro 《Neurology》1987,37(7):1258-1262
We studied two patients with nonfamilial olivopontocerebellar atrophy with skeletal myoclonus. Palatal or skeletal myoclonus is probably not a coincidental finding but another manifestation of the underlying disease. In both cases, the myoclonus was suppressed by administration of trihexyphenidyl, indicating a cholinergic disorder.  相似文献   
190.
Ambient light affects pulse oximeters   总被引:1,自引:0,他引:1  
  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