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   40176篇
  免费   3119篇
  国内免费   470篇
耳鼻咽喉   438篇
儿科学   1096篇
妇产科学   719篇
基础医学   5835篇
口腔科学   646篇
临床医学   3791篇
内科学   8478篇
皮肤病学   966篇
神经病学   2975篇
特种医学   1558篇
外国民族医学   16篇
外科学   4948篇
综合类   1320篇
现状与发展   1篇
一般理论   6篇
预防医学   3058篇
眼科学   793篇
药学   3276篇
  6篇
中国医学   736篇
肿瘤学   3103篇
  2023年   316篇
  2022年   803篇
  2021年   1367篇
  2020年   784篇
  2019年   1013篇
  2018年   1231篇
  2017年   881篇
  2016年   932篇
  2015年   1153篇
  2014年   1501篇
  2013年   1858篇
  2012年   2690篇
  2011年   2704篇
  2010年   1627篇
  2009年   1340篇
  2008年   1973篇
  2007年   1990篇
  2006年   1893篇
  2005年   1749篇
  2004年   1568篇
  2003年   1461篇
  2002年   1350篇
  2001年   1245篇
  2000年   1200篇
  1999年   1090篇
  1998年   387篇
  1997年   326篇
  1996年   298篇
  1995年   228篇
  1994年   224篇
  1993年   189篇
  1992年   565篇
  1991年   541篇
  1990年   508篇
  1989年   460篇
  1988年   479篇
  1987年   400篇
  1986年   387篇
  1985年   392篇
  1984年   263篇
  1983年   200篇
  1982年   124篇
  1981年   107篇
  1979年   218篇
  1978年   114篇
  1977年   125篇
  1976年   117篇
  1974年   138篇
  1972年   134篇
  1969年   111篇
排序方式: 共有10000条查询结果,搜索用时 15 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