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   3573篇
  免费   205篇
  国内免费   28篇
耳鼻咽喉   25篇
儿科学   116篇
妇产科学   141篇
基础医学   426篇
口腔科学   96篇
临床医学   346篇
内科学   751篇
皮肤病学   87篇
神经病学   178篇
特种医学   125篇
外国民族医学   4篇
外科学   511篇
综合类   108篇
预防医学   263篇
眼科学   99篇
药学   230篇
中国医学   27篇
肿瘤学   273篇
  2023年   50篇
  2022年   104篇
  2021年   162篇
  2020年   101篇
  2019年   104篇
  2018年   148篇
  2017年   105篇
  2016年   97篇
  2015年   112篇
  2014年   118篇
  2013年   195篇
  2012年   233篇
  2011年   230篇
  2010年   131篇
  2009年   131篇
  2008年   179篇
  2007年   180篇
  2006年   176篇
  2005年   184篇
  2004年   159篇
  2003年   133篇
  2002年   117篇
  2001年   67篇
  2000年   60篇
  1999年   46篇
  1998年   22篇
  1997年   18篇
  1996年   30篇
  1995年   21篇
  1994年   17篇
  1993年   20篇
  1992年   23篇
  1991年   21篇
  1990年   34篇
  1989年   23篇
  1988年   21篇
  1987年   28篇
  1986年   13篇
  1985年   18篇
  1984年   11篇
  1983年   18篇
  1982年   11篇
  1980年   13篇
  1979年   16篇
  1978年   11篇
  1977年   10篇
  1975年   8篇
  1974年   8篇
  1973年   17篇
  1966年   7篇
排序方式: 共有3806条查询结果,搜索用时 15 毫秒
101.
BackgroundBladder cancer is the most prevalent form of cancer in men among Egyptians, for whom tobacco smoke exposure and Schistosoma haematobium (SH) infection are the major risk factors. We hypothesized that functional polymorphisms in NAD(P)H:quinone oxidoreductase 1 (NQO1) and superoxide dismutase 2 (SOD2), modulators of the effects of reactive oxidative species, can influence an individual's susceptibility to these carcinogenic exposures and hence the risk of bladder cancer.MethodsWe assessed the effects of potential interactions between functional polymorphisms in the NQO1 and SOD2 genes and exposure to smoking and SH infection on bladder cancer risk among 902 cases and 804 population-based controls in Egypt. We used unconditional logistic regression to estimate the odds ratios (OR) and confidence intervals (CI) 95%.ResultsWater pipe and cigarette smoking were more strongly associated with cancer risk among individuals with the TT genotype for SOD2 (OR [CI 95%] = 4.41 [1.86–10.42]) as compared with those with the CC genotype (OR [CI 95%] = 2.26 [0.97–6.74]). Conversely, the risk associated with SH infection was higher among the latter (OR [CI 95%] = 3.59 [2.21–5.84]) than among the former (OR [CI 95%] = 1.86 [1.33–2.60]). Polymorphisms in NQO1 genotype showed a similar pattern, but to a much lesser extent. The highest odds for having bladder cancer following SH infection were observed among individuals with the CC genotypes for both NQO1 and SOD2 (OR [CI 95%] = 4.41 [2.32–8.38]).ConclusionOur findings suggest that genetic polymorphisms in NQO1 and SOD2 play important roles in the etiology of bladder cancer by modulating the effects of known contributing factors such as smoking and SH infection.  相似文献   
102.
In 2012, Tigray orthohantavirus was discovered in Ethiopia, but its seasonal infection in small mammals, and whether it poses a risk to humans was unknown. The occurrence of small mammals, rodents and shrews, in human inhabitations in northern Ethiopia is affected by season and presence of stone bunds. We sampled small mammals in two seasons from low- and high-density stone bund fields adjacent to houses and community-protected semi-natural habitats in Atsbi and Hagere Selam, where Tigray orthohantavirus was first discovered. We collected blood samples from both small mammals and residents using filter paper. The presence of orthohantavirus-reactive antibodies in blood was then analyzed using immunofluorescence assay (human samples) and enzyme linked immunosorbent assays (small mammal samples) with Puumala orthohantavirus as antigen. Viral RNA was detected by RT-PCR using small mammal blood samples. Total orthohantavirus prevalence (antibodies or virus RNA) in the small mammals was 3.37%. The positive animals were three Stenocephalemys albipes rats (prevalence in this species = 13.04%). The low prevalence made it impossible to determine whether season and stone bunds were associated with orthohantavirus prevalence in the small mammals. In humans, we report the first detection of orthohantavirus-reactive IgG antibodies in Ethiopia (seroprevalence = 5.26%). S. albipes lives in close proximity to humans, likely increasing the risk of zoonotic transmission.  相似文献   
103.
104.
105.
106.
A 36-year-old woman, who was 19 weeks pregnant presented with epigastric pain and a one-week history of repeated vomiting. Endoscopy revealed twisted stomach. CT scan of the chest showed figure of eight stomach consistent with gastric volvulus. Confirmation of diagnosis was made by laparatomy in which reduction of the oedematous stomach and excision of ischemic omental patch and repair of a huge paraesophageal hernia were performed. Two days after operation, abortion took place. Few days later, rapid deterioration in renal and hepatic function occurred followed by maternal death.  相似文献   
107.
Thymolipoma is an uncommon benign tumor (accounting for 2% to 9% of thymus tumors). We present the case of a 26-year-old man who sought medical attention for left-sided pleural pain of 3 months duration. Computed tomography showed a mass in the left side of the chest occupying both the anterior mediastinum and the left pleural cavity. This mass caused lung collapse and mediastinal shift. Magnetic resonance imaging revealed a large fatty tumor and transthoracic biopsy with radiological guidance confirmed the diagnosis. The tumor was resected through a left thoracotomy. No postsurgical complications occurred and the histopathological diagnosis was thymolipoma.  相似文献   
108.
AIM: To evaluate the prevalence of genetic and acquired prothrombotic risk factors and their association with the extent of fibrosis and fatty infiltration in patients with nonalcoholic fatty liver disease (NAFLD). METHODS: Forty-four patients with chronic hepatitis (28 men and 16 women, with mean age of 45±11 and 49±12 years, respectively) constituted the patient population of this study. The groups were divided as follows: 15 patients with fatty liver (FL); 15 with non-alcoholic steatohepatitis (NASH); 14 with chronic viral hepatitis (CH) diagnosed by histology and liver technetium scan or ultrasound; and 10 healthy individuals. Thrombophilic, coagulation factors and genetic mutations were diagnosed by standard hemostatic and molecular coagulation assays. RESULTS: Activated protein C (APC) resistance and protein S were the most prevalent thrombotic risk factors (6% and 10% in NAFLD vs 21% and 14% in CH; P<0.01 and P<0.05, respectively). One thrombotic risk factor was identified in 41% of patients (23% mild fibrosis, 18% severe fibrosis) and two thrombotic risk factors in 6% of patients with NAFLD and severe fibrosis. While no differences in APC ratio, lupus anticoagulant, fibrinogen, factor V Leiden, prothrombin, and MTHFR mutation were found. Protein S levels were significantly lower in NASH patients than in patients with FL alone (92±19 vs 106±2, P<0.01). Protein C levels were markedly higher in patients with NAFLD and mild or severe fibrosis as compared to the patients with CH, respectively (128±40 vs 96±14, P<0.001 or 129±36 CONCLUSION: Up to 46% of patients with NAFLD may have thrombotic risk factors, and the presence of thrombotic risk factors is correlated with the extent of hepatic fibrosis, suggesting a crucial role of the coagulation system in the pathogenesis of hepatic fibrosis.  相似文献   
109.

Background

The Glasgow Coma Scale (GCS) is the most widely accepted scale for assessing levels of consciousness, clinical status, as well as prognosis of traumatic brain injury (TBI) patients. The Full Outline of UnResponsiveness (FOUR) score is a new coma scale developed addressing the limitations of the GCS. The aim of this prospective cohort study was to compare the performance of the FOUR score vs. the GCS in predicting TBI outcomes.

Methods

From April to July 2011, 60 consecutive adult patients with TBI admitted to the Alexandria Main University Hospital intensive care units (ICU) were enrolled in the study. GCS and FOUR score were documented on arrival to emergency room. Outcomes were in-hospital mortality, unfavorable outcome [Glasgow outcome scale extended (GOSE) 1–4], endotracheal intubation, and ICU length of stay (LOS).

Results

Fifteen (25 %) patients died and 35 (58 %) had unfavorable outcome. When predicting mortality, the FOUR score showed significantly higher area under receiver operating characteristic curve (AUC) than the GCS score (0.850 vs. 0.796, p = 0.025). The FOUR score and the GCS score were not different in predicting unfavorable outcome (AUC 0.813 vs. 0.779, p = 0.136) and endotracheal intubation (AUC 0.961 vs. 0.982, p = 0.06). Both scores were good predictors of ICU LOS (r 2 = 0.40 [FOUR score] vs. 0.41 [GCS score]).

Conclusions

The FOUR score was superior to the GCS in predicting in-hospital mortality in TBI patients. There was no difference between both scores in predicting unfavorable outcome, endotracheal intubation, and ICU LOS.  相似文献   
110.
Clinical Rheumatology - To evaluate the impact of the coronavirus disease 2019 (COVID-19) pandemic on rheumatology practice. A cross-sectional web survey was designed by the members of the Arab...  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