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   942546篇
  免费   68537篇
  国内免费   1374篇
耳鼻咽喉   13114篇
儿科学   24658篇
妇产科学   23376篇
基础医学   134342篇
口腔科学   28362篇
临床医学   81877篇
内科学   185921篇
皮肤病学   19414篇
神经病学   73280篇
特种医学   37211篇
外国民族医学   79篇
外科学   154452篇
综合类   18197篇
现状与发展   1篇
一般理论   249篇
预防医学   62561篇
眼科学   21580篇
药学   73232篇
  3篇
中国医学   2173篇
肿瘤学   58375篇
  2018年   9598篇
  2017年   7430篇
  2016年   8181篇
  2015年   9358篇
  2014年   12664篇
  2013年   18240篇
  2012年   25244篇
  2011年   26185篇
  2010年   15419篇
  2009年   14768篇
  2008年   25428篇
  2007年   26460篇
  2006年   27122篇
  2005年   25978篇
  2004年   25052篇
  2003年   24026篇
  2002年   23481篇
  2001年   54766篇
  2000年   56578篇
  1999年   46989篇
  1998年   10768篇
  1997年   9495篇
  1996年   9620篇
  1995年   8944篇
  1994年   8295篇
  1993年   7617篇
  1992年   35501篇
  1991年   33929篇
  1990年   32751篇
  1989年   31889篇
  1988年   29006篇
  1987年   28267篇
  1986年   26305篇
  1985年   25164篇
  1984年   17845篇
  1983年   15149篇
  1982年   7812篇
  1981年   6786篇
  1979年   15801篇
  1978年   10616篇
  1977年   9057篇
  1976年   7884篇
  1975年   8634篇
  1974年   10472篇
  1973年   9861篇
  1972年   9358篇
  1971年   8857篇
  1970年   8429篇
  1969年   7928篇
  1968年   7201篇
排序方式: 共有10000条查询结果,搜索用时 640 毫秒
41.
42.
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   
43.
44.
45.
46.
47.
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   
48.
49.
50.
Background Immune checkpoint blockers (ICBs) activate CD8+ T cells, eliciting both anti-cancer activity and immune-related adverse events (irAEs). The relationship of irAEs with baseline parameters and clinical outcome is unclear.Methods Retrospective evaluation of irAEs on survival was performed across primary (N = 144) and secondary (N = 211) independent cohorts of patients with metastatic melanoma receiving single agent (pembrolizumab/nivolumab—sICB) or combination (nivolumab and ipilimumab—cICB) checkpoint blockade. RNA from pre-treatment and post-treatment CD8+ T cells was sequenced and differential gene expression according to irAE development assessed.Results 58.3% of patients developed early irAEs and this was associated with longer progression-free (PFS) and overall survival (OS) across both cohorts (log-rank test, OS: P < 0.0001). Median survival for patients without irAEs was 16.6 months (95% CI: 10.9–33.4) versus not-reached (P = 2.8 × 10−6). Pre-treatment monocyte and neutrophil counts, but not BMI, were additional predictors of clinical outcome. Differential expression of numerous gene pathway members was observed in CD8+ T cells according to irAE development, and patients not developing irAEs demonstrating upregulated CXCR1 pre- and post-treatment.Conclusions Early irAE development post-ICB is associated with favourable survival in MM. Development of irAEs is coupled to expression of numerous gene pathways, suggesting irAE development in-part reflects baseline immune activation.Subject terms: Immunotherapy, Melanoma  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