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   1707111篇
  免费   126022篇
  国内免费   3827篇
耳鼻咽喉   22178篇
儿科学   56843篇
妇产科学   46602篇
基础医学   242003篇
口腔科学   49630篇
临床医学   152294篇
内科学   335990篇
皮肤病学   39003篇
神经病学   131989篇
特种医学   64516篇
外国民族医学   242篇
外科学   260105篇
综合类   39243篇
现状与发展   4篇
一般理论   536篇
预防医学   124643篇
眼科学   40656篇
药学   124293篇
  7篇
中国医学   4558篇
肿瘤学   101625篇
  2021年   13106篇
  2019年   13801篇
  2018年   20356篇
  2017年   15572篇
  2016年   17044篇
  2015年   19327篇
  2014年   26737篇
  2013年   38656篇
  2012年   53585篇
  2011年   56298篇
  2010年   33244篇
  2009年   31034篇
  2008年   52270篇
  2007年   55613篇
  2006年   56115篇
  2005年   53408篇
  2004年   51630篇
  2003年   49004篇
  2002年   47192篇
  2001年   92196篇
  2000年   93940篇
  1999年   77256篇
  1998年   19841篇
  1997年   17360篇
  1996年   17499篇
  1995年   16786篇
  1994年   15330篇
  1993年   14097篇
  1992年   57435篇
  1991年   55318篇
  1990年   53003篇
  1989年   50785篇
  1988年   46150篇
  1987年   44950篇
  1986年   42244篇
  1985年   40007篇
  1984年   29366篇
  1983年   24918篇
  1982年   13902篇
  1979年   25536篇
  1978年   17578篇
  1977年   14911篇
  1976年   13878篇
  1975年   14566篇
  1974年   17638篇
  1973年   16946篇
  1972年   15681篇
  1971年   14461篇
  1970年   13435篇
  1969年   12518篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
结果 髌股关节的压力与应力随膝关节屈曲角度的增加而升高,随膝关节屈曲角度的减小而降低(图3~8).不同膝关节屈曲角度下弓步变化和跨步变化的髌股关节压力见表1.  相似文献   
994.
BACKGROUND: The MR and pathologic features of hippocampal sclerosis (HS) are well described and include volume decrease and T2-weighted signal increase for MRI, and neuron cell loss and gliosis for pathology. OBJECTIVE: To confirm the established correlation between hippocampal volumes and neuron cell counts, and to study the still controversial association between signal change and gliosis. METHODS: The authors studied 44 patients (22 men and 22 women; mean age at surgery, 37 years) with refractory temporal lobe epilepsy. Quantitative assessment of hippocampal volumes and T2 relaxometry, and neuron and glial cell count in the region CA1 and molecular layer of the dentate gyrus was performed. The proportion of glial fibrillary acidic protein (GFAP)-positive glial cells (reactive astrocytes) was indicated. RESULTS: In a stepwise regression, the ipsilateral hippocampal volume was predicted best by the neuron cell count in the dentate gyrus (p = 0.005, r = 0.4). Hippocampal T2 time, however, was predicted best by the glial cell count in the dentate gyrus (p = 0.01, r = 0.4). None of the other cell counts contributed to either model. In the dentate, 31% of the glial cells were reactive astrocytes, whereas in CA1, 5% were reactive. CONCLUSION: The results confirmed the correlation between hippocampal volumes and neuron cell counts. T2-weighted signal increase in the hippocampus was mainly influenced by gliosis in the dentate gyrus, where a high proportion of glial cells show abnormal activity. This activity may reflect changes important in the development of hippocampal epileptogenicity.  相似文献   
995.
Since the introduction of in vitro fertilization in 1978, reproductive medicine and its associated scientific fields have developed rapidly. In Germany, progress in this field is impeded by the German Embryo Protection Act. Exemplary are the prohibition of embryo selection and the ban on genetic testing of the pre-implantation embryo. Nevertheless, infertility treatment outcome has to be optimized within the framework of this law, with the aim of making treatment more efficient, lowering the incidence of multiple gestations, making ovarian hyperstimulation safer, as well as reducing the financial costs for the couple.  相似文献   
996.
997.
998.
BACKGROUND: In allergic conditions, the degree of skin test reactivity does not always correlate with the severity of clinical symptoms. Additional factors may contribute to the reported symptom severity. OBJECTIVES: To investigate the association between the magnitude of the skin prick test (SPT) response and the reported symptom severity in patients with allergic rhinitis and the possible modifying role of psychological factors. METHODS: One hundred four patients with allergic rhinitis and 23 with non-allergic rhinitis, classified according to their SPT response to 19 aeroallergens, were asked to rate the severity of five symptoms and to indicate whether their symptoms intensified on exposure to five common aeroallergens. They also completed a psychological questionnaire. Results Reported symptom severity of allergic rhinitis did not correlate with weal size for any of the aeroallergens tested or with the number of positive responses on SPT. It was not related to patient age, sex, or education. The reported symptoms severity correlated positively (0.29, P < 0.01) with reported symptom intensification on exposure to allergens. Moreover, both outcomes were positively associated with the psychological factors of hypochondriasis (0.20, P < 0.05 and 0.18, P < 0.05, respectively), and somatic awareness (0.24, P < 0.05 and 0.33, P < 0.01, respectively), but not with neuroticism. CONCLUSIONS: The severity of symptoms experienced by patients with allergic rhinitis is apparently not related to the magnitude of SPT response, but rather to psychological factors of hypochondriasis and somatic awareness. Physicians should be aware of the contribution of psychological factors to patient perceptions of the intensity of symptoms and of the intensification of symptoms on their exposure to allergens.  相似文献   
999.
1000.
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