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   1134589篇
  免费   75969篇
  国内免费   2944篇
耳鼻咽喉   15799篇
儿科学   35956篇
妇产科学   31502篇
基础医学   158546篇
口腔科学   34282篇
临床医学   91274篇
内科学   236785篇
皮肤病学   25848篇
神经病学   90804篇
特种医学   42980篇
外国民族医学   364篇
外科学   170823篇
综合类   20797篇
现状与发展   1篇
一般理论   338篇
预防医学   89268篇
眼科学   25107篇
药学   79189篇
中国医学   2827篇
肿瘤学   61012篇
  2021年   11196篇
  2019年   11665篇
  2018年   17034篇
  2017年   12388篇
  2016年   12586篇
  2015年   14287篇
  2014年   19729篇
  2013年   29050篇
  2012年   41808篇
  2011年   44213篇
  2010年   25242篇
  2009年   22879篇
  2008年   39280篇
  2007年   41847篇
  2006年   40883篇
  2005年   40697篇
  2004年   38459篇
  2003年   36678篇
  2002年   34372篇
  2001年   47467篇
  2000年   48968篇
  1999年   41539篇
  1998年   11590篇
  1997年   10394篇
  1996年   10317篇
  1995年   9472篇
  1994年   9058篇
  1993年   8530篇
  1992年   30983篇
  1991年   29583篇
  1990年   28807篇
  1989年   27638篇
  1988年   25623篇
  1987年   25062篇
  1986年   24119篇
  1985年   22845篇
  1984年   17049篇
  1983年   14479篇
  1982年   8639篇
  1979年   15582篇
  1978年   10839篇
  1977年   9164篇
  1976年   8632篇
  1975年   9616篇
  1974年   11390篇
  1973年   10910篇
  1972年   10262篇
  1971年   9524篇
  1970年   9215篇
  1969年   8630篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO.  相似文献   
72.
73.
74.
Plasma provided by COVID-19 convalescent patients may provide therapeutic relief as the number of COVID-19 cases escalates steeply worldwide. Prior findings in various viral respiratory diseases including SARS-CoV-related pneumonia suggest that convalescent plasma can reduce mortality, although formal proof of efficacy is still lacking. By reducing viral spread early on, such an approach may possibly downplay subsequent immunopathology. Identifying, collecting, qualifying and preparing plasma from convalescent patients with adequate SARS-CoV-2-neutralizing Ab titres in an acute crisis setting may be challenging, although well within the remit of most blood establishments. Careful clinical evaluation should allow to quickly establish whether such passive immunotherapy, administered at early phases of the disease in patients at high risk of deleterious evolution, may reduce the frequency of patient deterioration, and thereby COVID-19 mortality.  相似文献   
75.
76.
77.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
78.
79.
80.
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