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   6985篇
  免费   435篇
  国内免费   79篇
耳鼻咽喉   80篇
儿科学   62篇
妇产科学   128篇
基础医学   1141篇
口腔科学   177篇
临床医学   464篇
内科学   1262篇
皮肤病学   200篇
神经病学   463篇
特种医学   418篇
外科学   903篇
综合类   27篇
预防医学   218篇
眼科学   93篇
药学   953篇
中国医学   159篇
肿瘤学   751篇
  2023年   32篇
  2022年   24篇
  2021年   217篇
  2020年   122篇
  2019年   147篇
  2018年   228篇
  2017年   155篇
  2016年   271篇
  2015年   416篇
  2014年   412篇
  2013年   487篇
  2012年   808篇
  2011年   710篇
  2010年   408篇
  2009年   338篇
  2008年   446篇
  2007年   354篇
  2006年   339篇
  2005年   364篇
  2004年   305篇
  2003年   228篇
  2002年   176篇
  2001年   105篇
  2000年   102篇
  1999年   69篇
  1998年   25篇
  1997年   31篇
  1996年   19篇
  1995年   14篇
  1994年   16篇
  1993年   8篇
  1992年   14篇
  1991年   25篇
  1990年   13篇
  1989年   10篇
  1988年   13篇
  1987年   9篇
  1986年   8篇
  1985年   7篇
  1984年   3篇
  1981年   4篇
  1979年   3篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1968年   1篇
  1967年   1篇
  1966年   2篇
排序方式: 共有7499条查询结果,搜索用时 15 毫秒
1.
2.
3.

Background

Given the lack of established indications for elective nodal irradiation (ENI) in ypN0 patients after neoadjuvant chemotherapy (NAC) and breast-conserving surgery (BCS), we set out to investigate the role of ENI in ypN0 patients according to subtype and pathologic complete remission (pCR) status.

Patients and Methods

We analyzed 261 patients who received NAC followed by BCS and adjuvant radiotherapy in 13 institutions of the Korean Radiation Oncology Group from 2005 to 2011. The tumors were classified into one of 3 subtypes: luminal (estrogen receptor positive or progesterone receptor positive and HER2 negative), HER2 (HER2 positive), or triple negative (estrogen receptor, progesterone receptor, and HER2 negative). We compared locoregional control (LRC), disease-free survival (DFS), and overall survival (OS) according to ENI in different subgroups generated by the subtype and pCR statuses.

Results

In all patients, the 5-year LRC, DFS, and OS rates were 96.0%, 91.0%, and 96.8%, respectively. In all patients, axillary lymph node dissection was found to be the only favorable factor for LRC (P = .023) and DFS (P = .001). Age ≥ 50 years (P = .027), negative resection margin (P = .002), and axillary lymph node dissection (P = .002) were all favorable factors for OS. ENI did not affect LRC, DFS, or OS. Subgroup analysis by tumor subtype and pCR showed that ENI was not associated with greater LRC or DFS in any subgroups.

Conclusion

In ypN0 patients after NAC and BCS, ENI did not improve LRC or survival, regardless of subtype or primary tumor response. This result should be verified through larger prospective trials.  相似文献   
4.
5.
Objective: A systematic review reported that coffee consumption would decrease risk of colon cancer in Asian women. But the systematic review arises the issue of duplication, so that a meta-epidemiological study was conducted. Methods: The selection criteria were defined that a prospective cohort follow-up study conducted to evaluate coffee consumption and risk of colon cancer in Asian and showed adjusted relative risk and its 95% confidence interval. In order to conduct meta-analysis, the highest versus lowest method was applied to extract relative risk and its 95% confidence intervals of the highest category. Random effect model was applied if I-squared value was over 50%. Results: After avoiding duplication, 9 cohort data were selected for meta-analysis. The summary relative risk (and their 95% confidence intervals) [I-square value] were 0.90 (95% CI: 0.79-1.03) [0.0%] in men, and 0.64 (95% CI: 0.36-1.15) [65.9%] in women, respectively. Conclusions: The results suggest that coffee consumption is not associated with the risk of colon cancer in Asian men and women. The findings of this study are consistent with the results of two systematic reviews conducted under the same hypothesis and selection criteria. Additional epidemiological studies are needed for the inflection of colon cancer risk as the dose of coffee increases and the difference in the protective effect by sex.  相似文献   
6.
Objective: While it has been claimed that lung cancer occurs due to epigenetic mechanisms, four systematic reviews were reported to investigate the association between serum folate levels and lung cancer risk. Considering some methodological problems founded in the systematic review, a meta-epidemiological study was conducted. Methods: The selection criteria of this study were defined that a case-control study was conducted to determine the risk of lung cancer occurrence according to the concentration of serum folate and its results showed odds ratio and its 95% confidence interval. Additional paper was explored from cited lists of 4 papers selected by previous systematic reviews. Random effect model was applied if I-squared value was over 50%. Results: For 5 case-control studies selected, the summary odds ratios (and their 95% confidence intervals) were 0.82 (0.74-0.90) in men, 0.70 (0.62-0.79) in former smokers, and 0.86 (0.75-1.00) in non-smokers. Conclusion: Higher foliate levels can decrease lung cancer risk in men and former smokers. Especially, the protective effect was highest in former smokers compared in non-smokers and current smokers. Based on these facts, folate fortification programs to reduce lung cancer risk would be focused on former smokers in men. And some epidemiological studies are needed to provide a hypothesis to explain the sex differences in the association between folate and lung cancer risk.  相似文献   
7.
8.
9.
10.
The topography of the facial muscles differs between males and females and among individuals of the same gender. To explain the unique expressions that people can make, it is important to define the shapes of the muscle, their associations with the skin, and their relative functions. Three‐dimensional (3D) motion‐capture analysis, often used to study facial expression, was used in this study to identify characteristic skin movements in males and females when they made six representative basic expressions. The movements of 44 reflective markers (RMs) positioned on anatomical landmarks were measured. Their mean displacement was large in males [ranging from 14.31 mm (fear) to 41.15 mm (anger)], and 3.35–4.76 mm smaller in females [ranging from 9.55 mm (fear) to 37.80 mm (anger)]. The percentages of RMs involved in the ten highest mean maximum displacement values in making at least one expression were 47.6% in males and 61.9% in females. The movements of the RMs were larger in males than females but were more limited. Expanding our understanding of facial expression requires morphological studies of facial muscles and studies of related complex functionality. Conducting these together with quantitative analyses, as in the present study, will yield data valuable for medicine, dentistry, and engineering, for example, for surgical operations on facial regions, software for predicting changes in facial features and expressions after corrective surgery, and the development of face‐mimicking robots. Clin. Anat. 28:735–744, 2015. © 2015 Wiley Periodicals, Inc.  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