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   170864篇
  免费   12575篇
  国内免费   5281篇
耳鼻咽喉   2070篇
儿科学   3414篇
妇产科学   4574篇
基础医学   23641篇
口腔科学   4356篇
临床医学   16008篇
内科学   28773篇
皮肤病学   2806篇
神经病学   10529篇
特种医学   6047篇
外国民族医学   25篇
外科学   22489篇
综合类   15690篇
现状与发展   6篇
一般理论   40篇
预防医学   12703篇
眼科学   4295篇
药学   15923篇
  62篇
中国医学   4410篇
肿瘤学   10859篇
  2023年   1248篇
  2022年   2887篇
  2021年   4002篇
  2020年   2994篇
  2019年   2860篇
  2018年   3560篇
  2017年   2945篇
  2016年   2969篇
  2015年   4090篇
  2014年   5141篇
  2013年   5570篇
  2012年   8273篇
  2011年   8640篇
  2010年   5720篇
  2009年   4786篇
  2008年   6361篇
  2007年   6525篇
  2006年   6267篇
  2005年   5573篇
  2004年   4513篇
  2003年   4129篇
  2002年   3720篇
  2001年   7549篇
  2000年   7634篇
  1999年   6430篇
  1998年   2259篇
  1997年   1803篇
  1996年   1295篇
  1995年   1162篇
  1994年   1053篇
  1992年   3884篇
  1991年   3945篇
  1990年   3691篇
  1989年   3655篇
  1988年   3524篇
  1987年   3368篇
  1986年   3164篇
  1985年   3025篇
  1984年   2093篇
  1983年   1822篇
  1979年   1923篇
  1978年   1200篇
  1975年   1199篇
  1974年   1367篇
  1973年   1421篇
  1972年   1364篇
  1971年   1249篇
  1970年   1144篇
  1969年   1130篇
  1968年   1025篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
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   
103.
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   
104.
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   
105.
报告12例疸性腔皮病患者的性别与年龄构成、并发症、实验室检查、治疗经过和结果,对该病的病因、治疗和预后进行了讨论。  相似文献   
106.
鼻内窥镜下鼻中隔矫正术   总被引:5,自引:1,他引:4  
目的 :研究鼻内窥镜下鼻中隔矫正术的优点。方法 :鼻内窥镜下鼻中隔矫正术 5 0例 ,同期施行传统的鼻中隔矫正术 5 0例作为对照 ,分析两者手术时间、术中出血量及疼痛情况。结果 :鼻内窥镜组治愈率为96% ,手术时间 ( 35 .5 0± 5 .2 0 ) min,术中出血量 ( 2 3.2 2± 4.2 5 ) ml,疼痛发生率为 1 6% ;传统手术组治愈率为 90 % ,手术时间 ( 4 5 .64± 6.34) min,术中出血量 ( 31 .34± 5 .64) ml,疼痛发生率为 38%。经统计学分析两组治愈率差异无显著性 ( P>0 .0 5 ) ,鼻内窥镜组手术时间明显缩短 ( P<0 .0 1 ) ,术中出血量明显减少 ( P<0 .0 5 ) ,术中疼痛发生率明显降低 ( P<0 .0 5 )。结论 :鼻内窥镜下鼻中隔矫正术照明好 ,术野清晰 ,直视下手术 ,易剥离粘连处和及时发现粘膜损伤 ,手术时间短 ,术中出血量少 ,疼痛轻 ,术后并发症少 ,特别是鼻中隔矫正同期完成功能性鼻内窥镜手术及歪鼻矫正手术时更显示其优越性  相似文献   
107.
保留肾单位手术治疗早期小肾癌21例临床分析   总被引:1,自引:0,他引:1  
OBJECTIVE: To evaluate the clinical effects of nephron-sparing surgery in patients with early-stage small renal cell carcinoma. METHODS: Nephron-sparing surgery was performed in 21 patients with renal cell carcinoma including 1 with solitary kidney, 3 with unilateral tumor and contralateral renal compromise, and 17 with unilateral tumor and normal contralateral kidney. The diameter of the tumors ranged from 1.5 to 6.0 cm, with a mean of 2.8 cm. The tumor diameter in 17 patients with normal contralateral kidney was less than 4 cm (mean 2.5 cm) and the average diameter in 4 patients with contralateral renal compromise was 4.2 cm. Sixteen cases were in stage T(1), 4 in stage T(2), and 1 in stage T(3). Of the 21 patients, 4 underwent tumor enucleation, 10 polar nephrectomy and 7 wedge resection. RESULTS: All patients were followed up for an average of 40.8 months (7 to 66 months). One patient suffered a right lung and mediastinum metastasis 3 years after the surgery later and 1 with chronic glomerulonephritis required dialysis 27 months after the operation. No surgical complication or local recurrence were found in other patients. CONCLUSION: As a safe and effective therapy for early-stage small renal cell carcinoma, nephron-sparing surgery can be considered as the gold-standard therapy for patients with lesions less than 4 cm in T(1) and T(2) stages of localized unilateral tumor with normal contralateral kidney.  相似文献   
108.
109.
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   
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