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   1487篇
  免费   63篇
  国内免费   11篇
耳鼻咽喉   34篇
儿科学   25篇
妇产科学   48篇
基础医学   128篇
口腔科学   40篇
临床医学   137篇
内科学   353篇
皮肤病学   21篇
神经病学   97篇
特种医学   66篇
外科学   320篇
综合类   23篇
预防医学   34篇
眼科学   45篇
药学   102篇
中国医学   8篇
肿瘤学   80篇
  2023年   4篇
  2022年   12篇
  2021年   21篇
  2020年   17篇
  2019年   20篇
  2018年   31篇
  2017年   33篇
  2016年   33篇
  2015年   61篇
  2014年   58篇
  2013年   71篇
  2012年   110篇
  2011年   77篇
  2010年   50篇
  2009年   58篇
  2008年   137篇
  2007年   134篇
  2006年   146篇
  2005年   126篇
  2004年   111篇
  2003年   80篇
  2002年   61篇
  2001年   29篇
  2000年   23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   3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
  1972年   2篇
  1970年   1篇
排序方式: 共有1561条查询结果,搜索用时 15 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.
Hepatocyte activator inhibitor-1 (HAI-1) is a transmembrane serine protease inhibitor that regulates the conversion of latent to active hepatocyte growth factor (HGF). Studies supporting a role for the HGF pathway in prostate carcinogenesis prompted an analysis of HAI-1 expression in the prostate. Here we analyze the regulation of HAI-1 expression by androgen, oncogenic transformation, and cancer progression. Immunohistochemical analysis revealed that HAI-1 expression was restricted to prostate epithelium, where staining occurred primarily in basal and atrophic luminal epithelial cells. Compared to normal glands, HAI-1 expression was significantly increased in localized prostate cancer and was present in most prostate cancer metastases. HAI-1 protein expression levels were sensitive to androgen in normal epithelium but not in cancer. Although androgen did not increase HAI-1 protein expression levels in LNCaP cells, it decreased HAI-1 surface expression, consistent with previous data from our group (Martin DB, Gifford DR, Wright ME, Keller A, Yi E, Goodlett DR, Aebersold R, Nelson PS: Quantitative proteomic analysis of proteins released by neoplastic prostate epithelium. Cancer Res 2004, 64:347-355). HAI-1 overexpression in cancer was predictive of prostate-specific antigen recurrence (relative risk, 1.24). These results suggest that HAI-1 regulates the HGF Met axis on prostate epithelial cells and influences HGF mediated tumor invasion and metastasis.  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