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   120575篇
  免费   7341篇
  国内免费   1584篇
耳鼻咽喉   1613篇
儿科学   3020篇
妇产科学   4156篇
基础医学   18548篇
口腔科学   3644篇
临床医学   9412篇
内科学   21956篇
皮肤病学   2501篇
神经病学   8269篇
特种医学   4086篇
外国民族医学   3篇
外科学   17055篇
综合类   5252篇
一般理论   35篇
预防医学   8785篇
眼科学   2886篇
药学   10376篇
中国医学   826篇
肿瘤学   7077篇
  2021年   1037篇
  2019年   1091篇
  2018年   1677篇
  2017年   1208篇
  2016年   1229篇
  2015年   1490篇
  2014年   1943篇
  2013年   2522篇
  2012年   3662篇
  2011年   3928篇
  2010年   2348篇
  2009年   2095篇
  2008年   3498篇
  2007年   3742篇
  2006年   3719篇
  2005年   3244篇
  2004年   3065篇
  2003年   2844篇
  2002年   2695篇
  2001年   6786篇
  2000年   6973篇
  1999年   5729篇
  1998年   1843篇
  1997年   1388篇
  1996年   948篇
  1995年   879篇
  1992年   3755篇
  1991年   3851篇
  1990年   3587篇
  1989年   3580篇
  1988年   3455篇
  1987年   3303篇
  1986年   3110篇
  1985年   2980篇
  1984年   2063篇
  1983年   1800篇
  1982年   990篇
  1979年   1917篇
  1978年   1193篇
  1977年   997篇
  1976年   925篇
  1975年   1199篇
  1974年   1360篇
  1973年   1419篇
  1972年   1360篇
  1971年   1250篇
  1970年   1144篇
  1969年   1127篇
  1968年   1031篇
  1967年   901篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Smoking and stroke.   总被引:2,自引:0,他引:2  
The purpose of this review is to evaluate literature published since 1978 on the association between smoking and stroke. Two cohort studies found a dose-response relationship between the amount of cigarettes smoked per day and the relative risk of stroke. Also, two of the cohort studies found that when smoking ceased, the risk of stroke lessened (p less than 0.001). Nine case-control studies found a significant association between smoking and stroke for men and women. The biological association between smoking and stroke is plausible and several epidemiologic studies are supportive of this thesis. Additional, well-designed epidemiologic studies with a sufficient sample size to detect reasonably small odds ratios or relative risks (thus providing adequate statistical power) are warranted.  相似文献   
82.
1. The frequent occurrence of hypothalamo-pituitary dysfunction in patients with eating disorders as well as prior reports that nutritional and endocrine status influence pituitary morphology, led us to hypothesize that pituitary size and shape may be altered in patients with eating disorders. 2. Magnetic resonance imaging (MRI) does not use ionizing radiation and is currently one of the most feasible modalities available to study the pituitary gland in vivo. Using MRI, we have previously reported in a preliminary study that female patients with eating disorders had significantly smaller pituitary glands than controls. In addition MRI excluded any pituitary mass lesions. 3. In this report, we confirm our previous MRI findings and provide further evidence of pituitary abnormalities in an expanded sample of eating disorder patients. Preliminary data on pituitary volume estimates from MRI scans are provided for a subset of patients and controls.  相似文献   
83.
Following administration of phenothiazines for schizophrenia, a 25-year-old patient developed a malignant neuroleptic syndrome followed by bilateral periarticular ossification of the knees, with severely limited motion. Two years later, the patient regained useful motion after bilateral excision of the ossified tissue and intensive physiotherapy. No recurrence of ossification was observed 3 years after operation, and the patient has maintained almost normal motion.  相似文献   
84.
85.
86.
Both dopamine D1 and D2 receptors are present in rat retina. D1 receptors are positively coupled to adenylyl cyclase, while D2 receptors are negatively coupled. After intraocular administration of the neurotoxin 6-hydroxydopamine (6-OHDA) there is depletion of retinal dopamine by about 90%, as well as a decrease of the number of D1 and D2 receptor binding sites. Following the 6-OHDA lesion, there is an enhancement of the D1 receptor-stimulated accumulation of cyclic-AMP and a loss of D2 receptor-inhibited accumulation of cyclic-AMP. Our results suggest that some of the retinal D2 receptors are coupled to adenylyl cyclase and some are not.  相似文献   
87.
Q Guo  Z Guo 《中西医结合杂志》1989,9(8):472-4, 452
The effect of the traditional Chinese medicinal herbs enema and enteric-coated capsules in the treatment of ulcerative colitis (UC) were compared in 260 cases. The immune complexes and the dynamic change of autoantibodies were monitored in 28 out of the 260 cases before and after treatment. The following results were observed. (1) There was no significant difference in the total effective rate between the enema group and the oral capsule group (93.3% and 87.5% respectively), but the recovery rates of purulent hemafecia, mucusfecia and erosion accompanying colitis, etc. in the former group were higher than those in the latter (P less than 0.01). (2) The circulating immune complexes were found 43 times above the normal range in 17 cases with positive rate 60.7%, and tended to decrease as the condition became better after treatment. Antinuclear antibodies were determined by the indirect fluorescent immune method and the indirect enzyme labelling method and the positive rates were 53.6% and 64.7% respectively, both being much higher than those in the controls (P less than 0.01).  相似文献   
88.
A goal for the obstetrician and neonatologist is to screen for risk factors associated with intraventricular hemorrhage (IVH) in the low-birthweight infant. Perinatal events that lead to neonatal metabolic and cardiovascular derangements seem to provoke IVH, and conflicting reports have implicated labor as being contributory. A fetal heart rate (FHR) abnormality during premature labor may be a predictor of subsequent neonatal IVH. For this reason, 5 years of FHR tracings at two university medical centers were reviewed for inborn infants who were delivered after premature labor and weighed less than or equal to 2000 gm. Sixty-four infants developed IVH, but pre-existing labor with a discernible FHR pattern was recorded in only 38 (59%) cases. Interpretations were reassuring in 17 (45%) cases, suspicious in 7 (18%) cases, and ominous in 14 (37%) cases. This proportion of FHR patterns was not significantly different from a matched group of premature infants without IVH during the same period. Interpretations of intrapartum FHR patterns of low-birthweight infants are limited, especially before 30 weeks gestation, and not useful in predicting neonatal IVH.  相似文献   
89.
90.
The cementoblastoma is a rare benign tumor of odontogen origin that interests the roots of the teeth especially the lower molars. The evolution is often silent, the radiological exam is not specific, the diagnosis of certainty is histological. The surgical treatment assures the recovery without aftermath. The authors report a case of cementoblastoma at a patient of 37 years for which he has benefited of a resection by vestibular way and debate diagnosis and therapeutic modes of this affection.  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