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   1371篇
  免费   52篇
  国内免费   13篇
耳鼻咽喉   33篇
儿科学   27篇
妇产科学   42篇
基础医学   118篇
口腔科学   44篇
临床医学   125篇
内科学   342篇
皮肤病学   21篇
神经病学   93篇
特种医学   65篇
外科学   289篇
综合类   24篇
预防医学   33篇
眼科学   44篇
药学   85篇
中国医学   6篇
肿瘤学   45篇
  2023年   3篇
  2022年   9篇
  2021年   13篇
  2020年   13篇
  2019年   17篇
  2018年   25篇
  2017年   29篇
  2016年   26篇
  2015年   44篇
  2014年   55篇
  2013年   69篇
  2012年   89篇
  2011年   68篇
  2010年   47篇
  2009年   54篇
  2008年   131篇
  2007年   128篇
  2006年   134篇
  2005年   122篇
  2004年   108篇
  2003年   78篇
  2002年   59篇
  2001年   33篇
  2000年   24篇
  1999年   10篇
  1998年   1篇
  1997年   4篇
  1996年   2篇
  1995年   2篇
  1992年   7篇
  1991年   1篇
  1990年   2篇
  1989年   11篇
  1988年   1篇
  1986年   1篇
  1985年   4篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   3篇
  1980年   1篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
  1970年   1篇
  1966年   1篇
排序方式: 共有1436条查询结果,搜索用时 531 毫秒
1.
2.
OBJECTIVE: Gastric paresis in traumatic brain injury (TBI) hinders the effectiveness of enteral support in this patient group. In this study we have investigated the effect of metoclopramide on gastric emptying in TBI patients. METHOD: In this prospective, randomized, controlled, double-blind study, 19 TBI patients with Glasgow Coma Scale scores of 3-11 were included. In all patients, enteral nutrition was commenced with a nasogastric feeding tube within 48 hours of trauma. Patients were randomized into two groups. In the metoclopramide (M) group, 10 mg metoclopramide was delivered intravenously three times daily for 5 days. In the control (C) group, an equal volume of saline was administered. Besides demographics, gastric emptying according to a paracetamol absorption test at days 0 and 5, time to reach target nutritional requirements, gastric residues, intolerance to feeding, nutritional complications, and clinical outcomes were recorded for each patient. RESULTS: The gastric residue rates were 2.7+/-7.4 mL and 8.1+/-17.7 mL per 100 patient days for groups C and M respectively (p=0.408). Similarly, feeding intolerance and complication rates did not significantly differ between groups C and M, (respectively p=0.543 and 0.930). Gastric emptying parameters also were similar between the study groups. CONCLUSION: We were unable to document any advantage to using metoclopramide in TBI patients. Simple intragastric enteral feeding with close monitoring of the possible complications seems to be sufficient with acceptable morbidity rates.  相似文献   
3.
Intracerebral and intramedullary schwannomas are uncommon; but, in general, spinal intramedullary schwannomas are more frequent than intracerebral schwanomas. We present a case of right lateral ventricle schwannoma in a 21-year-old man and review the associated literature. The 21-year-old right-handed man presented with loss of the left-eye vision approximately 8 months before referral to an ophthalmologist. The patient was immediately subjected to computed tomography (CT) scan, which showed an enhanced lesion with cystic component in the right occipital horn of the lateral ventricle. And consecutively, he was admitted to our department. The tumor was evacuated via craniotomy with marked improvement in his clinical state. The postoperative course was uneventful and postoperative CT control showed no residue. On MRI control no recurrence was noted after a follow-up period of 8 years. Intracerebral schwannoma is a rare, benign neoplasm. It is usually located superficially or adjacent to a ventricle. Characteristic imaging features include cyst formation, calcification, and evidence of peritumoral edema or gliosis. The recognition of this benign and potentially curable neoplasm and its differentiation from other neoplasms, some of which have less favourable outcomes, is of obvious importance.  相似文献   
4.
Background/purpose: The localized or generalized skin thickness detected on mammography may reflect an underlying pathology of breast or a systemic disease involving the skin. The aim of this report is to describe the range of normal breast skin thickness in women using a film-screen mammographic technique.
Methods: Measurement of the mammographic skin thickness over different parts of the breast was performed in 144 women who had normal findings in a combined mammographic and ultrasonographic examination. Patients were grouped as premenopause, postmenopause and surgical menopause who were under continuous oestrogen treatment. The skin thickness in four regions (superior, inferior, medial, lateral) of both breasts was compared, and their relations with age, breast size, menopausal and hormonal status were investigated. The interobserver reliability was tested in a small subgroup of patients.
Results: Interobserver agreement was good for all measurements. The range of normal breast skin thickness was between 0.50 and 3.10 mm. There were no differences in skin thickness between the corresponding regions of the breasts, with significant differences between the regions in the same breast. While breast size increased with age, skin thickness decreased in all regions.
Conclusion: The breast size, age, regional variations and hormonal status of the patients should be considered when defining the normal range of skin thickness in mammographic examinations. We assume that upper limit of mammographic skin thickness should be set as 3.0 mm, regardless of the focal spot size and film-focus distance.  相似文献   
5.
Treatment of Anogenital Warts by Pulsed Dye Laser   总被引:2,自引:0,他引:2  
BACKGROUND: Treatment of anogenital warts is difficult in that the disease spectrum is wide. Moreover, varying degrees of improvement are obtained. OBJECTIVE: To study the treatment of persistent anogenital warts by pulsed dye laser. METHODS: Pulsed dye laser was used with the following settings: spot size 7 mm, pulse duration 1500 microsec, and fluence 7.5 J/cm2. Two different wavelengths were used: 585 and 595 nm. RESULTS: Lesions healed completely using both wavelengths after one treatment. CONCLUSION: Pulsed dye laser has been found to be safe, effective, satisfactory, and less traumatic compared to other options for treatment of perianal warts in children.  相似文献   
6.
7.
Sneddon's syndrome is characterized by livedo reticularis and cerebrovascular lesions. We report the cases of women (mean age, 36.2 +/- 8.1 years) diagnosed with Sneddon's syndrome based on the presence of livedo reticularis and characteristic cerebrovascular findings. Seven of these patients had cerebral infarcts on cranial computed tomography scan. Antiphospholipid antibodies were positive in 6 of these cases. Three cases had abnormal levels of antithrombin III. Analyses of chromosome 6 revealed no abnormalities. In 3 of the cases, investigation of the pedigrees revealed autosomal dominant traits. Two cases had epilepsy, and 3 had migraine. One case with migraine also had myasthenia gravis. In addition, we detected inferior altudinal hemianopia in 2 cases, cognitive functional disorder in 3 and depression in 2. Based on these findings, the entire vascular, haematologic, neurologic, and dermatologic systems should be evaluated in patients diagnosed with Sneddon's syndrome.  相似文献   
8.
In this paper, an intelligent system is presented for interpretation of the Doppler signals of the heart valve diseases based on the pattern recognition. This paper especially deals with combination of the feature extraction and classification from measured Doppler signal waveforms at the heart valve using the Doppler Ultrasound. Because of this, a wavelet packet neural network model developed by us is used. The model consists of two layers: wavelet and multi-layer perceptron. The wavelet layer is used for adaptive feature extraction in the time-frequency domain and is composed of wavelet packet decomposition and wavelet packet entropy. The multi-layer perceptron used for classification is a feed-forward neural network. The performance of the developed system has been evaluated in 215 samples. The test results showed that this system was effective in detecting Doppler heart sounds. The correct classification rate was about 94% for abnormal and normal subjects.  相似文献   
9.
10.
Molecular genetic studies in a seven‐year‐old boy and his mother demonstrated a novel 11 bp deletion in the TWIST gene (127del11), causing Saethre‐Chotzen syndrome. The mother had rather mild signs of the Saethre‐Chotzen syndrome; however, her son presented with marked acrocephalosyndactyly type 3, leading to craniotomy at three years. He also had recurrent infections and laboratory findings comparable with the hyper IgE syndrome, a rare primary immunodeficiency disorder. It is likely that the 11bp deletion caused the Saethre‐Chotzen syndrome in the patient and his mother, and another, not yet identified genetic defect, seen in the patient but not in the mother, is responsible for the hyper IgE phenotype. A combination of these two congenital conditions has not been described to date. © 2001 Wiley‐Liss, Inc.  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