全文获取类型
收费全文 | 1139篇 |
免费 | 66篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 26篇 |
妇产科学 | 38篇 |
基础医学 | 109篇 |
口腔科学 | 19篇 |
临床医学 | 94篇 |
内科学 | 216篇 |
皮肤病学 | 17篇 |
神经病学 | 104篇 |
特种医学 | 131篇 |
外科学 | 119篇 |
综合类 | 28篇 |
预防医学 | 135篇 |
眼科学 | 7篇 |
药学 | 93篇 |
肿瘤学 | 97篇 |
出版年
2023年 | 12篇 |
2022年 | 10篇 |
2021年 | 15篇 |
2020年 | 13篇 |
2019年 | 13篇 |
2018年 | 20篇 |
2017年 | 21篇 |
2016年 | 18篇 |
2015年 | 13篇 |
2014年 | 29篇 |
2013年 | 44篇 |
2012年 | 59篇 |
2011年 | 69篇 |
2010年 | 35篇 |
2009年 | 48篇 |
2008年 | 49篇 |
2007年 | 65篇 |
2006年 | 45篇 |
2005年 | 66篇 |
2004年 | 29篇 |
2003年 | 28篇 |
2002年 | 21篇 |
2001年 | 37篇 |
2000年 | 26篇 |
1999年 | 34篇 |
1998年 | 24篇 |
1997年 | 24篇 |
1996年 | 33篇 |
1995年 | 18篇 |
1994年 | 21篇 |
1993年 | 28篇 |
1992年 | 15篇 |
1991年 | 21篇 |
1990年 | 29篇 |
1989年 | 32篇 |
1988年 | 25篇 |
1987年 | 17篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 14篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1971年 | 9篇 |
1969年 | 6篇 |
排序方式: 共有1243条查询结果,搜索用时 15 毫秒
1.
Pseudomembranous colitis is not a rare complication of antibiotic therapy. 2000 surgical procedures with implantation of grafts in the aorto-iliac region were performed from 1974 through 1988; during this period 11 cases of CMP were observed. The Authors report their experience in regard to the various antibiotics administered. 相似文献
2.
3.
4.
Background
Official guidelines that promote evidence-based and cost-effective prescribing are of main relevance for obvious reasons. However, to what extent these guidelines are followed and their conditioning factors at different levels of the health care system are still insufficiently known. 相似文献5.
S Bonassi F Merlo N Pearce R Puntoni 《International journal of cancer. Journal international du cancer》1989,44(4):648-651
The association between occupational exposure to polycyclic aromatic hydrocarbons (PAH) and bladder cancer development was investigated in a population-based case-control study carried out in the Bormida valley, Italy. One hundred and twenty-one male cases and 342 male controls, matched age, were collected from local hospitals. Occupational exposure to PAH and aromatic amines (AA) was evaluated by means of a job exposure matrix, constructed specifically for this study. Subjects considered as sharing a "definite exposure to PAH" showed an increased risk even after adjustment for cigarette smoking and exposure to AA (OR = 2.14, 95% CL 0.82-5.60). No elevation in risk was found for the category "possible exposure to PAH" (OR = 1.05, 95% CL 0.45-2.44). The findings of this study are consistent with previous studies indicating PAH as a risk factor for bladder cancer. A possible residual confounding effect due to AA impurities is discussed. 相似文献
6.
Filaci G Contini P Fravega M Fenoglio D Azzarone B Julien-Giron M Fiocca R Boggio M Necchi V De Lerma Barbaro A Merlo A Rizzi M Ghio M Setti M Puppo F Zanetti M Indiveri F 《Human immunology》2003,64(1):9-20
Resident macrophages are mainly responsible for the clearance of apoptotic cells from tissue by phagocytosis. Phagocytosis of apoptotic cells is not accompanied by activation of inflammatory mechanisms, unlike what happens when necrotic phenomena occur. We analyzed the effect of phagocytosis of apoptotic bodies on macrophage cell functions. After phagocytosis of apoptotic cells macrophages were unable to present an exogenous antigen to autologous antigen-specific T-cell lines. The inhibition was mediated by different mechanisms including binding of apoptotic DNA to human leukocyte antigen (HLA) class II molecules of macrophages, decreased expression of co-stimulatory molecules and increased secretion of tumor growth factor beta (TGFbeta). When dendritic cells were cultured with macrophages phagocytosing apoptotic cells, or with their supernatant, impaired dendritic cell antigen presenting activity and reduced tumor necrosis factor alpha (TNFalpha) secretion were found. Our results suggest that: (1) the phagocytosis of apoptotic bodies inhibits macrophage antigen presentation; (2) such inhibition is mediated by the binding of apoptotic DNA to macrophage HLA class II molecules as well as by the activation of biological mechanisms that induce an anti-inflammatory functional behavior in macrophages; and (3) macrophages phagocytosing apoptotic cells inhibit antigen presentation of neighboring dendritic cells via TGFbeta secretion. These events are likely related to the preservation of healthy tissues from the onset of inflammation. 相似文献
7.
Epitope focus, clonal composition and Th1 phenotype of the human CD4 response to the secretory mycobacterial antigen Ag85 总被引:4,自引:0,他引:4
Valle MT Megiovanni AM Merlo A Li Pira G Bottone L Angelini G Bracci L Lozzi L Huygen K Manca F 《Clinical and experimental immunology》2001,123(2):226-232
Lymphoproliferation of healthy donors was tested against mycobacterial antigens (PPD, Ag85, Ag85 peptides). All PPD responders recognized the secretory antigen Ag85 and the peptide specificity for Ag85B was defined. Peptide 91-108 was recognized by 85% of donors. In addition, all CD4 T cell lines generated from 12 donors against PPD or Ag85 responded to 91-108. When this peptide was used to generate T cell lines, the cells responded also to tuberculins from atypical mycobacterial species. Thus the cross-reactive peptide behaved as quasi-universal. The analysis of TCR-BV gene usage by cell lines showed that most Ag85-specific T cells correspond to 91-108-specific clonotypes. Intracytoplasmic staining of cell lines after phorbol myristate acetate stimulation resulted in dominance of interferon-gamma (IFN-gamma)-IL-4 double-positive cells, whereas antigen stimulation resulted in production of IFN-gamma only. The data show that peptide 91-108 is the major focus of the CD4 response to mycobacterial antigens in peripheral blood mononuclear cells and in T cell lines from PPD responders. 相似文献
8.
Aravind Krishnan Joshua Hsu Jinny S. Ha Stephen R. Broderick Pali D. Shah Robert SD. Higgins Christian A. Merlo Errol L. Bush 《American journal of surgery》2021,221(4):731-736
PurposeWe aimed to assess the prognostic value of Neutrophil to Lymphocyte Ratio (NLR) on long-term outcomes and graft dysfunction after lung transplantation.MethodsWe retrospectively reviewed all patients receiving a lung transplant at our institution from 2011 to 2014. The primary exposure was elevated NLR at the time of transplant, defined by NLR>4. The primary outcomes were graft failure and three-year all-cause mortality. Multivariate logistic regression and Kaplan-Meier survival analysis were used to analyze outcomes.Results95 patients were included. 40 patients (42%) had an elevated NLR. Elevated NLR was associated with graft failure (OR: 4.7 [1.2–18.8], p = 0.02), and three-year mortality (OR: 5.4 [1.3–23.2], p = 0.03) on multivariate logistic regression. Patients with elevated NLR demonstrated significantly lower survival on Kaplan-Meier analysis (50% versus 74%, p = 0.02). The c-statistic for our multivariate model was 0.91.ConclusionElevated neutrophil to lymphocyte ratio is associated with poor long-term survival and graft failure after lung transplantation. 相似文献
9.
10.
Basolo F Venesio T Calvo S Fiore L Fontanini G Ciardiello F Toniolo A Liscia D Merlo G 《International journal of oncology》1994,4(6):1365-1370
Fibroblast growth factors (FGFs) are related polypeptides with mitogenic activity on cells of mesodermal and neuroectodermal origin. The Fgf-3 gene shares high homology with FGF-2 and its protein product can substitute FGF-2 as a growth factor. Other observations, however, indicate that Fgf-3 has specialized functions. We have investigated the effect of the expression and secretion of Fgf-3 on the growth and transformation of the human breast epithelial cell line MCF-10A. Overexpression of Fgf-3 stimulates proliferation of these cells in serum-free medium and induces anchorage-independent colony formation in soft agar. In contrast, these effects were not observed with purified FGF-1 and FGF-2 on either the parental or the Fgf-3-MCF-10A cells. Thus, Fgf-3 is distinct from FGF-1 and FGF-2 for its ability to induce cell proliferation and transformation of MCF-10A cells. This difference could be due, at least in part, to the expression of a specific set of FGF receptors with higher affinity for FGF-3 than FGF-1 or FGF-2. 相似文献