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   37424篇
  免费   3037篇
  国内免费   421篇
耳鼻咽喉   400篇
儿科学   1059篇
妇产科学   646篇
基础医学   5481篇
口腔科学   569篇
临床医学   3575篇
内科学   8111篇
皮肤病学   854篇
神经病学   2763篇
特种医学   1390篇
外国民族医学   16篇
外科学   4661篇
综合类   1319篇
现状与发展   1篇
一般理论   3篇
预防医学   2922篇
眼科学   757篇
药学   2880篇
  6篇
中国医学   639篇
肿瘤学   2830篇
  2023年   286篇
  2022年   663篇
  2021年   1283篇
  2020年   762篇
  2019年   987篇
  2018年   1166篇
  2017年   816篇
  2016年   839篇
  2015年   1030篇
  2014年   1329篇
  2013年   1675篇
  2012年   2440篇
  2011年   2426篇
  2010年   1467篇
  2009年   1248篇
  2008年   1821篇
  2007年   1859篇
  2006年   1774篇
  2005年   1664篇
  2004年   1487篇
  2003年   1400篇
  2002年   1307篇
  2001年   1173篇
  2000年   1140篇
  1999年   1025篇
  1998年   367篇
  1997年   320篇
  1996年   284篇
  1995年   225篇
  1994年   220篇
  1993年   185篇
  1992年   546篇
  1991年   516篇
  1990年   485篇
  1989年   447篇
  1988年   478篇
  1987年   391篇
  1986年   386篇
  1985年   380篇
  1984年   261篇
  1983年   199篇
  1982年   125篇
  1981年   107篇
  1979年   215篇
  1978年   113篇
  1977年   126篇
  1976年   115篇
  1974年   131篇
  1972年   130篇
  1969年   106篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
1.
European Radiology - The strongest adverse prognostic factor in myxoid/round cell liposarcomas (MRC-LPS) is the presence of a round cell component above 5% within the tumor bulk. Its identification...  相似文献   
2.
Introduction: The treatment of classical Hodgkin lymphoma (cHL) in children is a story of success. Nowadays, more than 90% of patients are cured and overall survival is nearly 100% at 5 years. Efforts have been made to avoid related effects of therapies; therefore, children are treated using different chemotherapy schemes in comparison with adults.

Areas covered: This review includes a view of the clinical classification and risk assessment in children suffering from HL. The chemotherapy more commonly employed is revisited. The use of PET/CT to evaluate the disease in order to guide therapy is analyzed. New options of chemotherapy and emerging immunotherapy are also included.

Expert opinion: In order to make the right treatment choice, a proper initial assessment of risk is mandatory. The choice of therapy in these kinds of patients must be done according to the experience of the team, and also, the cost and logistics related to the eligible scheme are very important. If possible, efforts must be made to include PET/CT in guiding therapy and avoiding overtreatment and long-term adverse effects in children. New options in immunotherapy are emerging and must be considered with caution in selected patients.  相似文献   

3.
4.
5.
6.

Objective

To systematically review literature on uptake and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and/or polio-containing vaccines in infants who were born preterm, with a low birth weight, and/or with chronic health conditions that were diagnosed within the first 6?months of life.

Methods

Using a standardized search strategy developed by a medical librarian, records were extracted from MEDLINE, Embase, Database of Abstracts of Reviews of Effects, and CINAHL up to May 8, 2018.

Results

Out of the 1997 records that were screened, we identified 21 studies that met inclusion criteria. Eleven studies assessed vaccine coverage and/or timeliness in preterm infants, 6 in low birth weight infants, and 7 in children with chronic health conditions. Estimates of coverage in these populations were highly variable, ranging from 40% to 100% across the vaccines and population groups.

Conclusions

There is a lack of studies reporting coverage and timeliness of routine immunizations in special populations of children.

Policy implications

Our review suggests a need for improved surveillance of immunization status in special populations of infants, as well as a need for standardization of reporting practices.  相似文献   
7.
8.
9.
Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas.  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