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   207篇
  免费   45篇
  国内免费   7篇
耳鼻咽喉   1篇
儿科学   4篇
妇产科学   9篇
基础医学   22篇
口腔科学   2篇
临床医学   18篇
内科学   102篇
皮肤病学   19篇
神经病学   1篇
特种医学   2篇
外国民族医学   1篇
外科学   19篇
综合类   2篇
预防医学   24篇
眼科学   1篇
药学   16篇
中国医学   3篇
肿瘤学   13篇
  2023年   4篇
  2022年   3篇
  2021年   9篇
  2020年   5篇
  2019年   11篇
  2018年   19篇
  2017年   19篇
  2016年   13篇
  2015年   11篇
  2014年   12篇
  2013年   21篇
  2012年   26篇
  2011年   17篇
  2010年   10篇
  2009年   10篇
  2008年   9篇
  2007年   10篇
  2006年   12篇
  2005年   8篇
  2004年   6篇
  2003年   1篇
  2002年   4篇
  2001年   2篇
  2000年   1篇
  1999年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1993年   1篇
  1992年   3篇
  1990年   2篇
  1989年   3篇
  1975年   1篇
  1965年   2篇
排序方式: 共有259条查询结果,搜索用时 31 毫秒
1.
Eighty-eight adenovirus (Ad) isolates and associated clinical data were collected from walk-in patients with influenza-like illness in Egypt during routine influenza surveillance from 1999 through 2002. Respiratory Ad distributions are geographically variable, and serotype prevalence has not been previously characterized in this region. Serotype identity is clinically relevant because it predicts vaccine efficacy and correlates strongly with both clinical presentation and epidemiological pattern. Species and serotype identities were determined using several well-validated multiplex PCR protocols culled from the literature and supplemented with a few novel primer sets designed to identify rare types. The isolates included common species B1 serotypes (Ad3 and Ad7), common species C serotypes (Ad1, Ad2, and Ad5), the less common species B2 serotype Ad11, and three isolates of the rare species B1 serotype Ad16. Two isolates that appear to be variant Ad16 were also identified. Fifteen coinfections of multiple adenoviral types, primarily AdB/AdC and Ad3/Ad7 dual infections, were detected. The majority of these were verified using redundant PCR tests targeted at multiple genes. PCR is able to resolve coinfections, in contrast to traditional serum neutralization tests. PCR is also comparatively rapid and requires very little equipment. Application of the method allowed an inclusive determination of the serotypes found in the Egyptian respiratory sample set and demonstrated that coinfections are common and may play a previously unrecognized role in adenovirus pathogenesis, evolution, and epidemiology. In particular, coinfections may influence adenoviral evolution, as interserotypic recombination has been identified as a source of emerging strains.  相似文献   
2.
The hepatoprotective and antimutagenic effects of the rosemary essential oil and the ethanolic extract were investigated using carbon tetrachloride and cyclophosphamide as hepatotoxic and mutagenic compounds, respectively. Our results revealed that i.g. administration of the rosemary ethanolic extract (0.15 g/100 g BW) to rats for 3 weeks produced the most pronounced hepatoprotective effect compared to silymarin (reference compound) due to the amelioration of most of the studied serum and liver parameters and confirmed by histopathological examination of the liver tissue. Pretreatment of mice for 7 days with the rosemary essential oil (1.1 mg/g BW) followed by i.p. injection with cyclophosphamide reduced significantly the induced mitodepression in the bone marrow cells of the animals. The potential hepatoprotective and antimutagenic activities of the rosemary ethanolic extract and essential oil, respectively, are attributed to the presence of a relatively high percentage of phenolic compounds with high antioxidant activity (according to our chemical studies).  相似文献   
3.

Purpose

To describe total fluid intake (TFI) according to socio-demographic characteristics in children and adolescents worldwide.

Methods

Data of 3611 children (4–9 years) and 8109 adolescents (10–18 years) were retrieved from 13 cross-sectional surveys (47 % males). In three countries, school classes were randomly recruited with stratified cluster sampling design. In the other countries, participants were randomly recruited based on a quota method. TFI (drinking water and beverages of all kinds) was obtained with a fluid-specific record over 7 consecutive days. Adequacy was assessed by comparing TFI to 80 % of adequate intake (AI) for total water intake set by European Food Safety Authority. Data on height, weight and socio-economic level were collected in most countries.

Results

The mean (SD) TFI ranged from [1.32 (0.68)] to [1.35 (0.71)] L/day. Non-adherence to AIs for fluids ranged from 10 % (Uruguay) to >90 % (Belgium). Females were more likely to meet the AIs for fluids than males (4–9 years: 28 %, OR 0.72, p = 0.002; 10–18 years: 20 %, OR 0.80, p = 0.001), while adolescents were less likely to meet the AI than children (OR 1.645, p < 0.001 in males and OR 1.625, p < 0.001 in females).

Conclusions

A high proportion of children and adolescents are at risk of an inadequate fluid intake. This risk is especially high in males and adolescents when compared with females or children categories. This highlights water intake among young populations as an issue of global concern.
  相似文献   
4.
5.

Background

Primary cutaneous amyloidosis (PCA) comprises three main forms: macular, lichen, and nodular amyloidosis. The current available treatments are quite disappointing.

Objectives

Assess and compare the clinical and histological changes induced by different modes of Fractional CO2 laser in treatment of PCA.

Patients and Methods

Twenty five patients with PCA (16 macular and 9 lichen amyloidosis) were treated by fractional CO2 using; superficial ablation (area A ) and deep rejuvenation (area B ). Each patient received 4 sessions with 4 weeks intervals. Skin biopsies were obtained from all patients at baseline and one month after the last session. Patients were assessed clinically and histologically (Congo red staining, polarized light). Patients were followed‐up for 3 months after treatment.

Results

Both modes yielded significant reduction of pigmentation, thickness, itching, and amyloid deposits (P‐value < 0.001). However, the percentage of reduction of pigmentation was significantly higher in area A (P‐value = 0.003). Pain was significantly higher in area B. Significant reduction in dermal amyloid deposits denotes their trans‐epidermal elimination induced by fractional photothermolysis.

Conclusion

Both superficial and deep modes of fractional CO2 laser showed comparable efficacy in treatment of PCA. Superficial mode being better tolerated by patients, is recommended as a valid therapeutic option. Lasers Surg. Med. 47:388–395, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
6.
The majority of people infected with chronic hepatitis C virus (HCV) in the European Union (EU) remain undiagnosed and untreated. During recent years, immigration to EU has further increased HCV prevalence. It has been estimated that, out of the 4.2 million adults affected by HCV infection in the 31 EU/ European Economic Area (EEA) countries, as many as 580 000 are migrants. Additionally, HCV is highly prevalent and under addressed in Eastern Europe. In 2013, the introduction of highly effective treatments for HCV with direct‐acting antivirals created an unprecedented opportunity to cure almost all patients, reduce HCV transmission and eliminate the disease. However, in many settings, HCV elimination poses a serious challenge for countries’ health spending. On 6 June 2018, the Hepatitis B and C Public Policy Association held the 2nd EU HCV Policy summit. It was emphasized that key stakeholders should work collaboratively since only a few countries in the EU are on track to achieve HCV elimination by 2030. In particular, more effort is needed for universal screening. The micro‐elimination approach in specific populations is less complex and less costly than country‐wide elimination programmes and is an important first step in many settings. Preliminary data suggest that implementation of the World Health Organization (WHO) Global Health Sector Strategy on Viral Hepatitis can be cost saving. However, innovative financing mechanisms are needed to raise funds upfront for scaling up screening, treatment and harm reduction interventions that can lead to HCV elimination by 2030, the stated goal of the WHO.  相似文献   
7.
8.
The discovery of Helicobacter hepaticus as a causal agent of hepatitis and hepatocellular carcinoma (HCC) in mice has stimulated interest in looking for Helicobacter species in human liver samples. In this study, we searched for association between H. pylori and HCV-related liver disease. Liver specimens were collected from eighty-five patients; they were divided into five different groups according to liver pathology (METAVIR system). Group I (the 1st control group) consisted of 16 patients with chronic hepatitis C without histological activity. Group II consisted of 25 patients with chronic active hepatitis C, Group III, 17 patients with HCV-related cirrhosis and Group IV, 16 patients with HCV-related cirrhosis and HCC. Group V (2nd control group) consisted of 11 patients suffering from gastro duodenal and gall bladder diseases but negative for HCV. All cases were tested by polymerase chain reaction on liver samples for the presence of H. pylori DNA Cag A gene. Routine biochemical, radiological and RT-PCR for HCV RNA were also performed for all cases. The positivity of H. pylori PCR CagA gene in liver tissue was directly proportional to the severity of liver pathology, this being 75%, 52.9% and 32% in groups IV, III and II, respectively, which was more significant than the 1st and 2nd control groups (P < 0.001). There was a significant difference between H. pylori PCR values when compared to METAVIR staging (F) in different groups (P = 0.001). Helicobacter pylori PCR (Cag A gene) was positive in about 28.2% cases of late fibrosis (F3 + F4) while positivity was (5.9%) in early fibrosis (F1 + F2) (P = 0.0001). There was significant difference between H. pylori PCR (Cag A gene) in liver tissue and METAVIR activity in different groups (P = 0.002) as most of H. pylori PCR-positive cases were METAVIR activity A1 and A2 (15.3% and 12.9%, respectively). There was no association between H. pylori PCR and quantitative HCV RNA (P = 0.531). Also there was no significant difference of Child-Pugh staging in the H. pylori PCR-positive group when compared to the negative group (P = 0.996). There may be an association between the presence of H. pylori (Cag A gene) in the liver and disease progression in HCV-related chronic hepatitis and cirrhosis with and without HCC.  相似文献   
9.
A series of novel benzo[d]oxazole derivatives ( 6a–n ) have been synthesized and biologically evaluated as potential inhibitors of acetylcholinesterases (AChE) and butyrylcholinesterase (BChE). The chemical structures of all final compounds were confirmed by spectroscopic methods. In vitro studies showed that most of the synthesized compounds are potent acetylcholinesterase and butyrylcholinesterase inhibitors. Among them, compounds 6a and 6j strongly inhibited AChE and BChE activities with IC50 values of 1.03–1.35 and 6.6–8.1 μm , respectively. Docking studies also provided the binding modes of action and identified hydrophobic pi forces as the main interaction.  相似文献   
10.
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