首页 | 官方网站   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   34594篇
  免费   2806篇
  国内免费   411篇
医药卫生   37811篇
  2023年   257篇
  2022年   364篇
  2021年   1072篇
  2020年   692篇
  2019年   885篇
  2018年   1084篇
  2017年   776篇
  2016年   763篇
  2015年   938篇
  2014年   1200篇
  2013年   1546篇
  2012年   2256篇
  2011年   2254篇
  2010年   1391篇
  2009年   1156篇
  2008年   1665篇
  2007年   1699篇
  2006年   1634篇
  2005年   1530篇
  2004年   1375篇
  2003年   1300篇
  2002年   1218篇
  2001年   1122篇
  2000年   1111篇
  1999年   980篇
  1998年   349篇
  1997年   300篇
  1996年   234篇
  1995年   213篇
  1994年   209篇
  1993年   174篇
  1992年   514篇
  1991年   502篇
  1990年   479篇
  1989年   442篇
  1988年   463篇
  1987年   384篇
  1986年   378篇
  1985年   369篇
  1984年   259篇
  1983年   189篇
  1982年   120篇
  1981年   105篇
  1979年   211篇
  1978年   111篇
  1977年   129篇
  1976年   113篇
  1974年   129篇
  1972年   130篇
  1969年   105篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
It is well recognized that the world population is ageing rapidly. Therefore, it is important to understand ageing processes at the cellular and molecular levels to predict the onset of age‐related diseases and prevent them. Recent research has focused on the identification of ageing biomarkers, including those associated with the properties of the Golgi apparatus. In this context, Golgi‐mediated glycosylation of proteins has been well characterized. Additionally, other studies show that the secretion of many compounds, including pro‐inflammatory cytokines and extracellular matrix–degrading enzymes, is modified during ageing, resulting in physical and functional skin degradation. Since the Golgi apparatus is a central organelle of the secretory pathway, we investigated its structural organization in senescent primary human dermal fibroblasts using confocal and electron microscopy. In addition, we monitored the expression of Golgi‐related genes in the same cells. Our data showed a marked alteration in the Golgi morphology during replicative senescence. In contrast to its small and compact structure in non‐senescent cells, the Golgi apparatus exhibited a large and expanded morphology in senescent fibroblasts. Our data also demonstrated that the expression of many genes related to Golgi structural integrity and function was significantly modified in senescent cells, suggesting a relationship between Golgi apparatus function and ageing.  相似文献   
2.
3.
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   
4.
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   

5.
6.
7.
8.
9.

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   
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-23

京公网安备 11010802026262号