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   22226篇
  免费   545篇
  国内免费   543篇
耳鼻咽喉   625篇
儿科学   1258篇
妇产科学   399篇
基础医学   2137篇
口腔科学   731篇
临床医学   1363篇
内科学   5016篇
皮肤病学   388篇
神经病学   1562篇
特种医学   594篇
外国民族医学   1篇
外科学   3645篇
综合类   518篇
一般理论   10篇
预防医学   2280篇
眼科学   545篇
药学   1348篇
  6篇
中国医学   374篇
肿瘤学   514篇
  2024年   22篇
  2023年   104篇
  2022年   149篇
  2021年   176篇
  2020年   152篇
  2019年   182篇
  2018年   185篇
  2017年   85篇
  2016年   170篇
  2015年   119篇
  2014年   179篇
  2013年   137篇
  2012年   2062篇
  2011年   2339篇
  2010年   589篇
  2009年   329篇
  2008年   1789篇
  2007年   2023篇
  2006年   1766篇
  2005年   1933篇
  2004年   1821篇
  2003年   1741篇
  2002年   1623篇
  2001年   1085篇
  2000年   1586篇
  1999年   731篇
  1998年   94篇
  1997年   16篇
  1996年   25篇
  1995年   21篇
  1994年   10篇
  1993年   7篇
  1992年   8篇
  1991年   6篇
  1990年   2篇
  1989年   7篇
  1988年   6篇
  1987年   5篇
  1986年   14篇
  1985年   2篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1978年   1篇
  1976年   1篇
  1967年   1篇
  1966年   1篇
  1957年   1篇
  1942年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Alternative surgical procedures to treat unclippable aneurysms of the intracavernous carotid artery include proximal vessel occlusion and trapping. Those techniques, even in patients with rich collateral vessels, are associated with risk of hemodynamic compromise and ischemic complications. Therefore, a safe treatment requires revascularization to maintain blood flow to the involved territories. We report the case of a 47-year-old female, with ischemic signs and symptoms and a right third nerve palsy caused by a giant aneurysm, partially trombosed, of the intracavernous carotid artery. The patient was submitted to trapping after a saphenous vein graft bypass from the external carotid artery to the supraclinoid internal carotid artery. The surgical result was good without complications.  相似文献   
992.
The objective of this study was to analyze some clinical and epidemiologic aspects, as well as the follow up of 180 patients with Bell's palsy. In the study population there was a predominance of female (66.7%). Two peaks of incidence in the age distribution were identified: third-fourth and sixth decades of life. In the group of 180 patients there were 198 events of facial paralysis, 17 recurrences and in one patient the paralysis was bilateral at the onset. In 15 patients (8.3%) there were recurrences of the facial paralysis, in 12 cases (70.6%) the recurrences were ipsilateral. The left side of the face was involved in 55.6% of the cases. In eight patients the paralysis occurred during pregnancy (n=5) or puerperium (n=3). As associated conditions we found: arterial hypertension (11.7%), diabetes mellitus (11.1%), pregnancy or puerperium (4.4%; 6.7% in the women), and neurocysticercosis (1.1%). In 72.8% of the cases no association with such conditions was found. In 22.8% of the patients some kind of sequelae were identified: hemifacial spasm (12.8%), partial recovery of the motor deficit (10.6%), syndrome of the crocodile tears (3.3%), sincinetic contraction (2.8%), and the Marcus Gunn inverse phenomenon (1.1%). In conclusion, this study shows that the idiopathic facial paralysis may lead to important sequelae in more than 20% of the patients.  相似文献   
993.
Recessive ataxia with ocular apraxia: review of 22 Portuguese patients   总被引:4,自引:0,他引:4  
BACKGROUND: The recessive ataxias are a heterogeneous group of neurodegenerative disorders characterized by cerebellar ataxia associated with a number of different neurologic, ophthalmologic, or general signs. They are often difficult to classify in clinical terms, except for Friedreich ataxia, ataxia-telangiectasia, and a relatively small group of rare conditions for which the molecular basis has already been defined. OBJECTIVES: To study the clinical presentation and to define diagnostic criteria in a group of Portuguese patients with ataxia and ocular apraxia, an autosomal recessive form without the essential clinical and laboratory features of ataxia-telangiectasia. PATIENTS AND METHODS: We reviewed 22 patients in 11 kindreds, identified through a systematic survey of hereditary ataxias being conducted in Portugal. RESULTS: Age at onset ranged from 1 to 15 years, with a mean of 4.7 years. The duration of symptoms at the time of last examination varied from 5 to 58 years. All patients presented with progressive cerebellar ataxia, the characteristic ocular apraxia, and a peripheral neuropathy. Associated neurologic signs included dystonia, scoliosis, and pes cavus. Magnetic resonance imaging was performed in 16 patients, all of whom showed cerebellar atrophy. CONCLUSIONS: Ataxia with ocular apraxia may be more frequent than postulated before, and may be identified clinically using the following criteria: (1) autosomal recessive transmission; (2) early onset (for most patients in early childhood); (3) combination of cerebellar ataxia, ocular apraxia, and early areflexia, with later appearance of the full picture of peripheral neuropathy; (4) absence of mental retardation, telangiectasia, and immunodeficiency; and (5) the possibility of a long survival, although with severe motor handicap.  相似文献   
994.
PURPOSE: The efficacy and safety of transjugular liver biopsy used to obtain liver specimens in patients with coagulation disorders have been widely proven. However, histopathologic examination is not always possible because of fragmented samples provided by the aspiration technique. Recently, an automated device with a Tru-Cut-type needle was designed. In this randomized controlled trial, the use of this new device is compared with the traditional method in terms of efficacy and safety. METHOD: Fifty-six patients were included in the study; 28 were randomized to undergo the aspiration technique and 28 were randomized to undergo the automated biopsy technique. RESULTS: Correct positioning of the device was achieved in 93% of patients undergoing the aspiration technique and 96% of patients undergoing the automated biopsy technique (P = NS). Mean duration of the procedure and total number of passes were significantly higher in the aspiration needle group than in the automated device group (22.6 min +/- 12.6 vs 15.5 min +/- 9.4; P = .03, and 3.3 min +/- 1.9 vs 1.5 min +/- 0.63; P < .001, respectively). The number of portal tracts was significantly higher in the automated device group (4.7 +/- 2.5 vs. 2.7 +/- 3.4; P < .05). Adequate specimens for histopathologic evaluation were obtained in 26 patients in the automated device group and 24 patients in the aspiration needle group (92.8% vs 85.7%; P = NS), but a definite histopathologic diagnosis was more frequently obtained with the automated biopsy device (68% vs 43%; P = .05). No significant differences were observed in complication rates (7.14% vs. 10.7%; P = NS). CONCLUSION: The automated biopsy device for transjugular liver biopsy is more effective than an aspiration needle in obtaining good samples for a definite histologic diagnosis.  相似文献   
995.
996.
Pneumocephalus associated with spinal problems is very rare. Association with encephalomeningitis secondary to a fistula after an infected elective lumbar spine fusion has not been previously reported. The authors report a case in which the clinical onset of pneumoencephalomeningitis occurred after an airplane flight. CT-scan and lumbar puncture were used to make diagnosis; the treatment was based on parenteral antibiotics. The symptoms and signs of infection and neurological deficit resolved but the fistula remained. Diagnosis in such cases must be based upon CT-scan and lumbar puncture. Treatment should consist of systemic antibiotic therapy. Surgical management of infection and fistula is desirable, should the status of the patient allow such a treatment. In any case, as airplane flights in such cases may predispose to pneumocephalus, patients with an infected CSF fistula should avoid airplane flights until the problem is solved.  相似文献   
997.
PURPOSE: The aim of this study was to evaluate the benefits of an oral isosmolar solution of electrolytes (ISE) administered to interrupt a prolonged fasting period in children undergoing an elective surgical procedure under general anesthesia. METHODS: Forty unpremedicated children aged 3 to 12 years, ASA I, undergoing a surgical procedure requiring general anesthesia were assigned randomly to 1 of 2 groups. Group 1 consisted of patients with an overnight fasting period for milk and solids of at least 8 hours. In group 2, patients under a similar fasting period received a volume of 4 mL/kg of an oral ISE 3 hours before completing the fasting period. After anesthetic induction, blood glucose level (BGL) was quantified, and patients underwent an endoscopic examination to obtain the gastric content to determine the residual gastric volume (RGV) and pH levels. RESULTS: In group 1, the RGV was 0.78 +/- 0.44 mL/kg, pH was 1.75 +/- 0.38, and BGL was 86.4 +/- 14.5. In group 2, the RGV was 0.40 +/- 0.29 mL/kg, pH was 3.18 +/- 0.61, and BGL was 85.1 +/- 12.6. Only RGV and pH were significantly different between groups. CONCLUSION: A prolonged fasting period interrupted with oral ISE administration resulted in an RGV of low risk, without counterbalancing a potential fasting-induced hypoglycemia.  相似文献   
998.
999.
1000.
A 34-year-old pregnant paraplegic woman with a T12 medullary lesion in chronic phase underwent cesarean delivery in the thirty-seventh week due to pelvic-cephalic disproportion. After failure of epidural anesthesia related to technical difficulties, general anesthesia was provided. A hypertensive crisis developed during surgery but was resolved within minutes after administration of hydralazine. No further complications arose. Pregnancy in a patient with medullary lesion in chronic phase is considered high risk, requiring special care due to extraordinary changes in pathophysiology caused by the lesion in addition to changes directly related to gestation. The main complications that arise are decreased respiratory volume and arterial pressure, increased incidence of thromboembolic events, anemia, urinary tract infections, premature birth, unusual progression of delivery and autonomic hyperreflexia, which is the most serious. When a hypertensive peak develops in such patients, the anesthesiologist must first rule out autonomic hyperreflexia, which has an incidence of 85% in lesions over T7 and has also been described in patients with lower lesions.  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