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   577篇
  免费   38篇
  国内免费   5篇
耳鼻咽喉   6篇
儿科学   36篇
妇产科学   9篇
基础医学   65篇
口腔科学   31篇
临床医学   57篇
内科学   109篇
皮肤病学   8篇
神经病学   28篇
特种医学   65篇
外科学   80篇
综合类   29篇
一般理论   1篇
预防医学   38篇
眼科学   2篇
药学   14篇
中国医学   5篇
肿瘤学   37篇
  2023年   5篇
  2022年   6篇
  2021年   17篇
  2020年   7篇
  2019年   14篇
  2018年   10篇
  2017年   11篇
  2016年   11篇
  2015年   14篇
  2014年   8篇
  2013年   24篇
  2012年   27篇
  2011年   26篇
  2010年   34篇
  2009年   17篇
  2008年   12篇
  2007年   15篇
  2006年   20篇
  2005年   30篇
  2004年   20篇
  2003年   16篇
  2002年   7篇
  2001年   6篇
  2000年   17篇
  1999年   14篇
  1998年   25篇
  1997年   18篇
  1996年   24篇
  1995年   10篇
  1994年   14篇
  1993年   10篇
  1992年   6篇
  1991年   10篇
  1990年   9篇
  1989年   13篇
  1988年   13篇
  1987年   16篇
  1986年   10篇
  1985年   7篇
  1984年   7篇
  1983年   4篇
  1982年   8篇
  1981年   2篇
  1980年   5篇
  1979年   3篇
  1978年   2篇
  1977年   3篇
  1976年   8篇
  1975年   2篇
  1971年   2篇
排序方式: 共有620条查询结果,搜索用时 31 毫秒
101.
This article describes the different imaging techniques used in the study of the small bowel. We define the technical requirements that conventional small bowel follow through studies must fulfill to be considered an efficacious examination (individualized study of each bowel loop by compression and fluoroscopy); we evaluate the different types of enteroclysis, giving special attention to the biphasic type, which is the most commonly employed; we discuss the advantages and disadvantages of biphasic enteroclysis with respect to conventional small bowel follow through studies; and finally we evaluate the role of modern techniques of image acquisition, tomodensitometry and magnetic resonance imaging used together with traditional techniques. Small bowel studies require accurate indications for radiologic study, thorough and meticulous examination, and careful interpretation of the images obtained. Although the modern techniques of magnetic resonance and computed tomography enteroclysis are no better than conventional small bowel follow through or enteroclysis at demonstrating the details of the intestinal mucosa, they are of great use in solving the problem of the superimposition of intestinal loops and provide information about the intestinal wall and possible extraluminal pathology.  相似文献   
102.
Bovine lactoferrin (bLf), a component of milk and a dietary supplement, modulates intestinal immunity at effector and inductor sites. Considering the regional difference in intestinal compartments and the dynamics of local cytokine-producing cells in the gut across time, the aim of this work was to characterize the effects of bLf on the proximal small intestine in a BALB/c murine model of oral administration. Male BALB/c mice were treated with oral bLf vs. saline control as mock by buccal deposition for 28 days. Intestinal secretions were obtained at different time points and cells were isolated from Peyer’s patches (PP) and lamina propria (LP) of the proximal small intestine as representative inductor and effector sites, respectively. Total and specific anti-bLF IgA and IgM were determined by enzyme-immuno assay; the percentages of IgA+ and IgM+ plasma cells (PC) and cytokine-producing CD4+ T cells of PP and LP were analyzed by flow cytometry. We found that total and bLf-specific IgA and IgM levels were increased in the intestinal secretions of the bLf group in comparison to mock group and day 0. LP IgA+ PC and IgM+ PC presented an initial elevation on day 7 and day 21, respectively, followed by a decrease on day 28 in comparison to mock. Higher percentages of CD4+ T cells in LP were found in the bLf group. Cytokines-producing CD4+ T cells populations presented a pattern of increases and decreases in the bLf group in both LP and PP. Transforming growth factor beta (TGF-β)+ CD4+ T cells showed higher percentages after bLf administration with a marked peak at day 21 in both LP and PP in comparison to mock-treated mice. Oral bLf exhibits complex immune properties in the proximal small intestine, where temporal monitoring of the inductor and effector compartments reveals patterns of rises and falls of different cell populations. Exceptionally, TGF-β+ CD4+ T cells show consistent higher numbers after bLf intervention across time. Our work suggests that isolated measurements do not show the complete picture of the modulatory effects of oral bLf in immunological sites as dynamic as the proximal small intestine.  相似文献   
103.

Background

Oxidative damage (OD) biomarkers have been used to evaluate metabolic stress undergone by alcoholic individuals. In alcoholic patients, these biomarkers are usually measured at late stages, i.e., when the alcoholic patients are showing clear signs of impaired hepatic function. OD biomarkers are sensitive indicators of impaired metabolic function, and might be useful in early stages of alcohol consumption to identify individuals who are at greater risk of damage in later stages of alcohol consumption. The aim of the present work was to evaluate some OD biomarkers in young people at early stages of alcohol consumption.

Methods

The study was carried out in a group of young people (18–23 years old) who drank alcohol, Youngsters Exposed to Alcohol (YEA) with an average intake of 118 g of ethanol/week, and a control group (CG) of non-drinkers. Blood counts, alcohol dehydrogenase (ADH) activity, glutathione peroxidase (GSH-Px) activity, oxidative damage to DNA, and lipid peroxidation were determined in both groups.

Results

The anthropometric and blood parameters of both groups were similar and no clinical symptoms of hepatic damage were observed. Nevertheless, ADH activity, lipid peroxidation, and percentage of damaged DNA cells were higher in the YEA group than in the control group. In contrast, GSH-Px activity was lower in the YEA group than in the control group.

Conclusion

Alteration in OD biomarkers can be found in individuals with 4–5 years of alcohol drinking history. To our knowledge, this is the first study giving evidence of OD in individuals at early stages of alcohol abuse.  相似文献   
104.
105.
106.
Aim:   Human epidermal growth factor receptor 2 (HER2) overexpression is associated with poor prognosis and the frequency of HER2 positivity in breast cancer patients varies among different regions of the world. We studied HER2 expression in Turkish breast cancer patients.
Methods:   HER 2 expression was evaluated immunohistochemically in 107 breast cancer patients. HER2 expression was reported as negative or positive (3+) according to cellular membrane staining characteristics. The frequency of HER2 overexpression, distribution according to clinical characteristics, effect on survival and effect of chemotherapy on survival in relation to HER2 overexpression was evaluated.
Results:   The median age of patients was 49 years (range 27–76). HER2 was 3+ in 34 patients (31.8%). There was no significant difference in age, menopausal status, histopathology, lymph node involvement, stage and estrogen and/or progesterone receptor positivity in relation to HER2 expression. Forty-three patients (40.2%) relapsed and 21 patients (19.6%) died during the follow-up period. There was no significant difference in the relapse rate, distribution of relapse sites and death rate in relation to HER2 expression. The 3- and 5-year disease free survival rates were 67.1 and 40.5%, and the overall survival rates were 87.5 and 66.1%, respectively. Survival rate and calculated survival time were relatively shorter in HER2 3+ patients than in non-HER2 3+ patients, but these differences were not statistically significant. HER2 status did not affect survival period according to chemotherapy group.
Conclusion:   Immunohistochemistry findings of HER2 expression in Turkish breast cancer patients were similar to those found in the published reports. A shorter survival period was observed in HER2 3+ patients, but the difference was not statistically significant.  相似文献   
107.
目的:观察静心电针法治疗围绝经期综合征的临床疗效。方法:将符合标准的围绝经期患者60例随机分为治疗组(30例)和对照组(30例)。治疗组给予静心电针法治疗,对照组给予克龄蒙治疗,均治疗3个周期。分别于治疗前、治疗1个月、治疗3个月(即治疗结束)、治疗后3个月及治疗后6个月进行随访,采用改良的Kupperman指数(KI)进行症状评分,并于治疗前、治疗结束各检测1次血清雌二醇(E2)、卵泡刺激素(FSH)、黄体生成激素(LH)。结果:治疗组和对照组的总有效率比较差异无统计学意义(90.00%vs.93.33%,P>0.05)。2组KI评分,治疗后各时间点与治疗前比较差异均有统计学意义(P<0.01),2组之间各时间点差异无统计学意义(P>0.05),2组在治疗期间,KI均有下降,当治疗结束后3个月与6个月时,KI评分稍有上升,对照组上升稍多,但2组之间差异无统计学意义(P>0.05)。2组治疗后,性激素水平均得到改善(P<0.01),但2组之间差异无统计学意义(P>0.05)。结论:静心电针法治疗围绝经期综合征,安全、疗效好,值得推广应用。  相似文献   
108.
109.
1临床资料患儿,女性,4岁。因间断性腹痛1月加重伴黑便15d,呕吐2d入院。患儿病前无明确外伤史,其母于入院前15d发现左膝部有损伤痕,已愈合,行腹部B超检查,提示肝胆肾正常,胰大小正常,边界清,实质回声均匀,主胰管不扩张,肝前区肝肾夹角及脾肾夹角可见53mm的液性暗区,内见肠管蠕动  相似文献   
110.
目的探讨不同类型肾脏占位病变的超声造影特点。方法对照病理诊断结果分析76例肾脏占位病变Sono Vue超声造影特征。结果肾恶性肿瘤62例,良性肿瘤14例。肾恶性肿瘤超声造影剂的充盈和消退呈多样性,以同步增强和快增强多见,造影剂的快速消退和缓慢消退之间无明显差别,差异无统计学意义(P>0.05)。恶性肿瘤典型的表现是整个病灶弥漫增强,轮廓边界清晰,呈"亮球"征(95.2%),并多有假包膜(87.1%)。肾错构瘤表现为无假包膜的不均匀增强,而肾囊肿始终无增强。结论超声造影有助于肾占位病变的鉴别诊断和预后判断。  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