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   3453篇
  免费   179篇
  国内免费   55篇
耳鼻咽喉   37篇
儿科学   140篇
妇产科学   48篇
基础医学   427篇
口腔科学   62篇
临床医学   283篇
内科学   595篇
皮肤病学   51篇
神经病学   306篇
特种医学   137篇
外科学   470篇
综合类   30篇
预防医学   517篇
眼科学   102篇
药学   221篇
中国医学   10篇
肿瘤学   251篇
  2023年   20篇
  2022年   24篇
  2021年   42篇
  2020年   31篇
  2019年   51篇
  2018年   47篇
  2017年   36篇
  2016年   52篇
  2015年   49篇
  2014年   73篇
  2013年   104篇
  2012年   160篇
  2011年   180篇
  2010年   93篇
  2009年   91篇
  2008年   192篇
  2007年   205篇
  2006年   176篇
  2005年   172篇
  2004年   130篇
  2003年   126篇
  2002年   125篇
  2001年   111篇
  2000年   106篇
  1999年   98篇
  1998年   47篇
  1997年   46篇
  1996年   40篇
  1995年   42篇
  1994年   41篇
  1993年   29篇
  1992年   68篇
  1991年   56篇
  1990年   80篇
  1989年   73篇
  1988年   53篇
  1987年   52篇
  1986年   71篇
  1985年   47篇
  1984年   32篇
  1983年   38篇
  1981年   22篇
  1979年   36篇
  1978年   20篇
  1976年   19篇
  1975年   24篇
  1974年   20篇
  1973年   19篇
  1972年   20篇
  1969年   27篇
排序方式: 共有3687条查询结果,搜索用时 15 毫秒
71.
72.
Chemotherapy-induced morphonuclear modifications were monitored in vivo by means of the digital cell image analysis of Feulgen-stained nuclei. Two experimental models were used, i.e. the P388 mouse leukaemia and the MXT mouse mammary carcinoma. The drugs used were doxorubicin, etoposide and cyclophosphamide. The results indicate that the chemotherrapy induced a significant decrease in the MXT tumour growth and a significant increase in the survival of the P388 leukaemic mice. These effects were accompanied at the morphonuclear level by an increase in the nuclear area, by modifications in the DNA content in accordance with the effects of the drugs on the cells cycle and by several modifications in the chromatin texture in accordance with the effects of the drugs on the cells cycle and by several modifications in the chromatin texture in accordance with the model or drugs studied. While there were neither homogeneous morphonuclear changes in all treatment groups nor clearcut correlations between the morphonuclear changes and tumour growth or the survival of the animals, the present study nertherless shows that it is possible, at least partly, to monitor in vivo certain chemotherapy-induced effects occurring at the morphonuclear level, and subsequently to obtain information on the mode of action of the drugs.  相似文献   
73.
Vasoactive intestinal polypeptide (VIP) immunoreactivity is present in varicosities and fibers in the hypothalamic paraventricular nucleus (PVN) in normal control animals. Adrenalectomy and lactation combined with colchicine treatment results in the appearance of a large population of VIP-immunopositive cell bodies in the parvocellular part of the PVN. Adrenalectomy, as well as lactation, significantly increases the number of VIP-positive fibers in the external zone of the median eminence. These observations suggest that the VIP-immunopositive neurons in the PVN may participate in regulating prolactin and corticotropin secretion.  相似文献   
74.
75.
76.
77.
Modern population based oral health management requires a complete understanding of the impact of disease in order to provide efficient and effective oral health care and guidance. Periodontitis is an important cause of tooth loss and has been shown to be associated with a number of systemic conditions. The impact of oral conditions and disorders on quality of life has been extensively studied. However, the impact of periodontitis on quality of life has received less attention. This review summarizes the literature on the impact of periodontitis on oral health‐related quality of life (OHRQoL). Relevant publications were identified after searching the MEDLINE and EMBASE electronic databases. Screening of titles and abstracts and data extraction was conducted. Only observational studies were included in this review. Most of the reviewed studies reported a negative impact of periodontitis on OHRQoL. However, the reporting standards varied across studies. Moreover, most of the studies were conducted in developed countries.  相似文献   
78.
79.
80.

Background

The development of erythropoiesis-stimulating agents (ESAs) with extended serum half-lives has allowed marked prolongation of the administration intervals. The level of oxidative stress is increased in chronic kidney disease, and is reportedly decreased after long-term ESA treatment. However, the effect of different dosing regimens of ESAs on oxidative stress has not been elucidated.

Methods

Five-sixths nephrectomized (NX) rats received either 0.4 μg/kg darbepoetin alfa (DA) weekly or 0.8 μg/kg DA fortnightly between weeks 4 and 10. NX animals receiving saline and a sham-operated (SHAM) group served as controls. The levels of oxidized and reduced glutathione (GSSG, GSH) were followed from blood samples drawn fortnightly.

Results

During the follow-up, the ratios GSSG/GSH showed similar trends in both DA groups, levels being significantly lower than those in the SHAM group at weeks 8 and 10. GSSG levels were lower than the baseline throughout the study in all groups except for NX controls. The GSH levels were increased in all three NX groups (weeks 6–10) compared with both the baseline and the SHAM group

Conclusion

Our results suggest that the extent of oxidative stress is similar in response to different dosing regimens of DA in 5/6 NX rats when comparable hemoglobin levels are maintained. These findings remain to be confirmed in chronic kidney disease patients.  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