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   226995篇
  免费   9669篇
  国内免费   561篇
医药卫生   237225篇
  2023年   1159篇
  2022年   1711篇
  2021年   4320篇
  2020年   2377篇
  2019年   4393篇
  2018年   6359篇
  2017年   4060篇
  2016年   4182篇
  2015年   4574篇
  2014年   5773篇
  2013年   8482篇
  2012年   13457篇
  2011年   14044篇
  2010年   7429篇
  2009年   6114篇
  2008年   11601篇
  2007年   12255篇
  2006年   11859篇
  2005年   11559篇
  2004年   10669篇
  2003年   9956篇
  2002年   9583篇
  2001年   6862篇
  2000年   7406篇
  1999年   5946篇
  1998年   1499篇
  1997年   1061篇
  1992年   3120篇
  1991年   2913篇
  1990年   2868篇
  1989年   2503篇
  1988年   2331篇
  1987年   2167篇
  1986年   2174篇
  1985年   2020篇
  1984年   1480篇
  1983年   1281篇
  1979年   1590篇
  1978年   1069篇
  1977年   1007篇
  1975年   1152篇
  1974年   1428篇
  1973年   1461篇
  1972年   1376篇
  1971年   1323篇
  1970年   1263篇
  1969年   1326篇
  1968年   1306篇
  1967年   1176篇
  1966年   1069篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
BACKGROUND: Artemisia species pollen represents a major cause of allergy in Central Europe. Variations in the pollen season, the influence of climate variables and the prevalence of pollinosis to it were analyzed in Poznan, in western Poland between 1995 and 2004. METHODS: A Hirst volumetric spore trap was used for atmospheric sampling. Pollination date trend analysis and Spearman correlation tests were performed. Skin prick tests (SPT) and allergen specific immunoglobulin (lg)E antibody measurements were performed in 676 and 524 patients, respectively. RESULTS: The Artemisia species pollen season grew longer due to a clear advance in the starting day and only a slightly earlier end point; the peak day also came slightly earlier. Rainfall in the first fortnight of July highly influenced pollen season severity. Temperature was directly correlated with daily Artemisia species pollen levels; relative humidity was inversely correlated. Twelve percent of patients had a positive SPT reaction to Artemisia species. Their symptoms were rhinitis and conjunctivitis (15%), atopic dermatitis (15%), chronic urticaria (14.3%), bronchial asthma (2.4%), and facial and disseminated dermatitis (1.3%). Elevated specific IgE concentrations were detected in the sera of 10.1% of patients. CONCLUSIONS: Artemisia species pollen is an important cause of pollinosis in western Poland. Pollen season intensity is highly influenced by rainfall in the previous weeks. Trends towards earlier season starts and longer duration, possibly caused by climate change, may have an impact on the allergic population.  相似文献   
92.
PTH fragments consisting of the C-terminal portion of the molecule may have biologic effects and may modify the actions of PTH. Evidence for the presence of a C-terminal PTH receptor further supports a biologic role for such fragments. Because C-PTH fragments accumulate in patients with renal insufficiency, it is possible that they may contribute to renal bone disease. The precise role of circulating C-PTH fragments in the pathogenesis, diagnosis, and management of renal osteodystrophy, however, remains to be determined. Future studies of the biologic effects and regulation of these fragments may lead to better understanding of skeletal biology and may also improve our approach to the diagnosis and treatment of renal bone disease.  相似文献   
93.
94.
95.
96.
97.
98.
99.
Hypoxia is related to poor prognosis because it is associated to chemo-and radioresistance. During recent years the evolution of imaging methods like PET/CT and MRI has meant the appearance of new perspectives with direct implications in radiation therapy. We discuss previous experiences in staging, planning and in the follow-up process with these techniques for measuring tumour hypoxia.  相似文献   
100.
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