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   4595篇
  免费   228篇
  国内免费   28篇
耳鼻咽喉   13篇
儿科学   84篇
妇产科学   45篇
基础医学   506篇
口腔科学   56篇
临床医学   275篇
内科学   1457篇
皮肤病学   66篇
神经病学   382篇
特种医学   169篇
外科学   799篇
综合类   14篇
预防医学   132篇
眼科学   115篇
药学   165篇
中国医学   3篇
肿瘤学   570篇
  2023年   47篇
  2022年   69篇
  2021年   156篇
  2020年   72篇
  2019年   93篇
  2018年   114篇
  2017年   89篇
  2016年   122篇
  2015年   115篇
  2014年   168篇
  2013年   224篇
  2012年   287篇
  2011年   328篇
  2010年   179篇
  2009年   155篇
  2008年   271篇
  2007年   274篇
  2006年   277篇
  2005年   275篇
  2004年   241篇
  2003年   222篇
  2002年   221篇
  2001年   81篇
  2000年   63篇
  1999年   57篇
  1998年   54篇
  1997年   27篇
  1996年   26篇
  1995年   26篇
  1994年   23篇
  1993年   19篇
  1992年   34篇
  1991年   26篇
  1990年   25篇
  1989年   37篇
  1988年   39篇
  1987年   33篇
  1986年   27篇
  1985年   27篇
  1984年   17篇
  1983年   20篇
  1982年   12篇
  1981年   19篇
  1980年   15篇
  1979年   21篇
  1978年   16篇
  1977年   17篇
  1975年   13篇
  1970年   9篇
  1968年   12篇
排序方式: 共有4851条查询结果,搜索用时 10 毫秒
101.
Inflammation substantially affects the risk of oral malignancy. Pro-inflammatory cytokine, interferon (IFN)-γ, confers anti-tumor activity using several different mechanisms. Conversely, higher expression of interleukin (IL)-17 is associated with worse prognosis. Monocyte chemotactic protein (MCP)-1 correlates positively with poor long-term survival of head and neck squamous cell carcinoma (HNSCC) patients. IL-1α affects cancer associated fibroblasts and macrophages, and promote several malignant phenotypes including immune suppression. Some anti-inflammatory cytokines, including IL-10 and transforming growth factor (TGF)-β, relate to pro-tumoral activities.Among immune checkpoint modulators, programmed death (PD-)1 and PD-ligand (L)1 facilitate oral squamous cell carcinoma (OSCC) cell evasion from immune surveillance, and the expression status of these has a prognostic value.OSCCs contain tumor associated macrophages (TAMs) as major stromal cells of their tumor microenvironment. Among the two distinctive states, M2 macrophages support tumor invasion, metastasis and immune suppression. Crosstalk between TAMs and OSCC or cancer-associated fibroblasts (CAF) plays an important role in the progression of OSCC.Clinical trials with blocking antibodies against IL-1α or melanoma-associated antigens have been reported as therapeutic approaches against OSCCs. The most promising approach activating antitumor immunity is the blockade of PD-1/PD-L1 axis. Manipulating the polarization of pro-tumorigenic macrophages has been reported as a novel therapeutic approach.  相似文献   
102.
103.
104.
To develop more effective vaccines and strategies to regulate chronic inflammatory diseases, it is important to understand the mechanisms of immunological memory. Factors regulating memory CD4+ T helper (Th)-cell pool size and function remain unclear, however. We show that activation of type I invariant natural killer T (iNKT) cells with glycolipid ligands and activation of type II natural killer T (NKT) cells with the endogenous ligand sulfatide induced dramatic proliferation and expansion of memory, but not naïve, CD4 T cells. NKT cell-induced proliferation of memory Th1 and Th2 cells was dependent largely on the production of IL-2, with Th2-cell proliferation also affected by loss of IL-4. Type II NKT cells were also required for efficient maintenance of memory CD4 T cells in vivo. Activation of iNKT cells resulted in up-regulation of IFN-γ expression by memory Th2 cells. These IFN-γ–producing memory Th2 cells showed a decreased capability to induce Th2 cytokines and eosinophilic airway inflammation. Thus, activated NKT cells directly regulate memory CD4 T-cell pool size and function via the production of cytokines in vivo.  相似文献   
105.
106.
Although it is well known that certain characteristics, such as older age, female gender, hypertension, and high body mass index, are closely associated with severe arterial tortuosity among patients undergoing transradial coronary angiography, few data are available regarding useful predictors of severe arterial tortuosity among geriatric patients. The purpose of the present study was to evaluate the characteristics of geriatric patients with severe tortuosity of the right subclavian artery or brachiocephalic artery. The coronary angiographic reports of patients with severe tortuosity of the right subclavian artery or brachiocephalic artery and age- and gender-matched control patients were retrospectively evaluated. A total of 847 consecutive patients underwent right transradial coronary angiography. Of these patients, 48 (5.7%) had severe tortuosity (29 women, age 73.4 ± 8.6 years). The factors associated with severe arterial tortuosity were greater body mass index (odds ratio 1.17, p = 0.02), the presence of a prominently projected aortic arch on a chest radiograph (odds ratio 5.62, p <0.01), and lower serum creatinine value (odds ratio 0.05, p <0.01). In conclusion, the presence of a prominently projected aortic arch on the chest radiograph is a useful predictor of severe arterial tortuosity.  相似文献   
107.
108.
109.
A 62-year-old man with diffuse large B-cell lymphoma received five courses of R-CHOP chemotherapy. The patient developed cellulitis in the bilateral lower extremities without fever, and blood culture yielded Helicobacter cinaedi after five-day culture. Although the response to tazobactam/piperacillin (TAZ/PIPC) was prompt, cellulitis recurred immediately after discontinuation of the drug. Even after two months of treatment with PIPC plus amikacin followed by amoxicillin, it recurred again soon after stopping the antibiotics. H. cinaedi reportedly causes bacteremia and cellulitis in immunocompromised patients mostly in patients with acquired immunodeficiency syndrome. Only sporadic cases have been reported in association with hematological malignancies. Physicians should be aware of H. cinaedi as one of the causative pathogens of bacteremia and cellulitis in patients with hematological malignancies. Longer incubation period of blood culture is needed to detect the microbe and long-term use of antimicrobials is required to prevent recurrent cellulitis.  相似文献   
110.
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