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   5213篇
  免费   284篇
  国内免费   34篇
耳鼻咽喉   157篇
儿科学   77篇
妇产科学   258篇
基础医学   651篇
口腔科学   56篇
临床医学   456篇
内科学   1559篇
皮肤病学   52篇
神经病学   445篇
特种医学   90篇
外科学   627篇
综合类   33篇
一般理论   1篇
预防医学   184篇
眼科学   68篇
药学   409篇
中国医学   4篇
肿瘤学   404篇
  2023年   25篇
  2022年   187篇
  2021年   369篇
  2020年   85篇
  2019年   126篇
  2018年   152篇
  2017年   111篇
  2016年   137篇
  2015年   167篇
  2014年   219篇
  2013年   289篇
  2012年   408篇
  2011年   425篇
  2010年   207篇
  2009年   142篇
  2008年   348篇
  2007年   381篇
  2006年   330篇
  2005年   309篇
  2004年   331篇
  2003年   305篇
  2002年   217篇
  2001年   20篇
  2000年   19篇
  1999年   23篇
  1998年   25篇
  1997年   14篇
  1996年   9篇
  1995年   12篇
  1994年   13篇
  1993年   8篇
  1992年   12篇
  1991年   6篇
  1990年   9篇
  1989年   8篇
  1988年   8篇
  1987年   4篇
  1986年   16篇
  1985年   6篇
  1983年   3篇
  1982年   5篇
  1981年   8篇
  1980年   5篇
  1979年   2篇
  1978年   4篇
  1977年   3篇
  1976年   3篇
  1975年   3篇
  1971年   2篇
  1968年   2篇
排序方式: 共有5531条查询结果,搜索用时 15 毫秒
991.
992.

Background

Cases of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are increasing in the pediatric population. Their growing prevalence coincides with the obesity epidemic. Assessment of the incidence requires liver biopsies on a representative population sample, which are hampered by the absence of indications for invasive examination on children without clinical symptoms. The aim of the current study was to assess the incidence of liver steatosis in the population of children up to 18 years old from Lower Silesia.

Methods

We retrospectively reviewed 342 medico-legal autopsy reports from 2000 to 2009. We separated a group of 256 children whose death was caused by trauma. Liver steatosis was diagnosed according to the results of histopathological examinations and typical macroscopic imaging.

Results

In the 265 children who died from trauma, liver steatosis was reported in 11 (4.2%) children (6 boys) aged between 6 months and 18 years old. Six of the 11 children (54.5%) were found to be overweight. In all 342 children, steatosis was found in 18 (5.3%) children (13 boys), while NASH was diagnosed in 1 (0.3%). Excess body weight was observed in 55.6% (10/18) of children with steatosis.

Conclusions

Liver steatosis can occur at any age, even in infancy. Being overweight is a very important risk factor. Gross examination of the liver is insufficient for the diagnosis of steatosis because of its lower sensitivity and specificity. Verification of liver steatosis requires reference histopathological examination.  相似文献   
993.
994.
Abstract

Introduction: Near-infrared (NIR) and red-to-near-infrared (R/NIR) radiation are increasingly applied for therapeutic use. R/NIR-employing therapies aim to stimulate healing, prevent tissue necrosis, increase mitochondrial function, and improve blood flow and tissue oxygenation. The wide range of applications of this radiation raises questions concerning the effects of R/NIR on the immune system.

Methods: In this review, we discuss the potential effects of exposure to R/NIR light on immune cells in the context of physical parameters of light.

Discussion: The effects that R/NIR may induce in immune cells typically involve the production of reactive oxygen species (ROS), nitrogen oxide (NO), or interleukins. Production of ROS after exposure to R/NIR can either be inhibited or to some extent increased, which suggests that detailed conditions of experiments, such as the spectrum of radiation, irradiance, exposure time, determine the outcome of the treatment. However, a wide range of immune cell studies have demonstrated that exposure to R/NIR most often has an anti-inflammatory effect. Finally, photobiomodulation molecular mechanism with particular attention to the role of interfacial water structure changes for cell physiology and regulation of the inflammatory process was described.

Conclusions: Optimization of light parameters allows R/NIR to act as an anti-inflammatory agent in a wide range of medical applications.  相似文献   
995.
Our research was conducted to determine the algorithm changes during the treatment of submandibular sialolithiasis. Two time periods were compared between 2004–2008 and 2009–2012. The turning point was December 2008, when sialendoscopy procedure was introduced. In the first period, 48 patients were treated: 31 outpatient duct incisions with stone evacuation and 17 surgical excision of submandibular gland. In the second period, 207 sialendoscopy procedures were performed on 197 patients. Out of this particular group, 158 patients were diagnosed with pathological obstruction of salivary glands and 64 of them were confirmed to have sialolithiasis of submandibular gland. Deposits of calcifications in 40 individuals (62.5 %) affected by sialolithiasis were removed endoscopically; however, in 21 patients, due to the increased circumference of the stone, the intimate association of deposits within the wall of the duct along with its presence inside the deep portions of the gland, double approach (incision of the floor of the mouth in hilar area and sialendoscopy) was performed. Three individuals had their salivary glands totally removed due to the presence of calcified deposits within the glandular parenchyma. Our results allow us to affirm that sialendoscopy is the current treatment of choice for submandibular glands affected by sialoliths. Indication for a complete removal of the gland is becoming uncommon as a first line treatment although still indispensable in chosen cases.  相似文献   
996.
Impaired mitochondrial capacity may be implicated in the pathology of chronic metabolic diseases. To elucidate the effect of ethyl pyruvate supplementation on skeletal muscles metabolism we examined changes in activities of mitochondrial and antioxidant enzymes, as well as sulfhydryl groups oxidation (an indirect marker of oxidative stress) during the development of obesity. After 6 weeks feeding of control or high fat diet, Wistar rats were divided into four groups: control diet, control diet and ethyl pyruvate, high fat diet, and high fat diet and ethyl pyruvate. Ethyl pyruvate was administered as 0.3% solution in drinking water, for the following 6 weeks. High fat diet feeding induced the increase of activities 3-hydroxyacylCoA dehydrogenase, citrate synthase, and fumarase. Moreover, higher catalase and superoxide dismutase activities, as well as sulfhydryl groups oxidation, were noted. Ethyl pyruvate supplementation did not affect the mitochondrial enzymes’ activities, but induced superoxide dismutase activity and sulfhydryl groups oxidation. All of the changes were observed in soleus muscle, but not in extensor digitorum longus muscle. Additionally, positive correlations between fasting blood insulin concentration and activities of catalase (p = 0.04), and superoxide dismutase (p = 0.01) in soleus muscle were noticed. Prolonged ethyl pyruvate consumption elevated insulin concentration, which may cause modifications in oxidative type skeletal muscles.  相似文献   
997.
Hamartomas are tumour-like malformations, consisting of disorganized normal tissues, typical of the site of tumour manifestation. Familial manifestation of hamartomatous polyps can be noted in juvenile polyposis syndrome (JPS), Peutz-Jeghers’ syndrome (PJS), hereditary mixed polyposis syndrome (HMPS) and PTEN hamartoma tumour syndrome (PHTS). All the aforementioned syndromes are inherited in an autosomal dominant manner and form a rather heterogenous group both in respect to the number and localization of polyps and the risk of cancer development in the alimentary tract and other organs. Individual syndromes of hamartomatous polyposis frequently manifest similar symptoms, particularly during the early stage of the diseases when in several cases their clinical pictures do not allow for differential diagnosis. The correct diagnosis of the disease using molecular methods allows treatment to be implemented earlier and therefore more effectively since it is followed by a strict monitoring of organs that manifest a predisposition for neoplastic transformation.  相似文献   
998.
999.
1000.
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