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   241篇
  免费   11篇
耳鼻咽喉   1篇
儿科学   2篇
妇产科学   2篇
基础医学   28篇
口腔科学   7篇
临床医学   23篇
内科学   75篇
皮肤病学   3篇
神经病学   7篇
特种医学   2篇
外科学   24篇
综合类   4篇
预防医学   61篇
药学   8篇
肿瘤学   5篇
  2024年   1篇
  2023年   1篇
  2022年   3篇
  2021年   11篇
  2019年   6篇
  2018年   6篇
  2017年   2篇
  2016年   4篇
  2015年   10篇
  2014年   6篇
  2013年   12篇
  2012年   14篇
  2011年   17篇
  2010年   11篇
  2009年   3篇
  2008年   18篇
  2007年   23篇
  2006年   21篇
  2005年   10篇
  2004年   21篇
  2003年   21篇
  2002年   18篇
  2001年   2篇
  2000年   3篇
  1998年   1篇
  1997年   1篇
  1991年   1篇
  1988年   1篇
  1986年   2篇
  1985年   2篇
排序方式: 共有252条查询结果,搜索用时 31 毫秒
1.
The net impact of cytomegalovirus (CMV) DNAemia on overall mortality (OM) and nonrelapse mortality (NRM) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a matter of debate. This was a retrospective, multicenter, noninterventional study finally including 749 patients. CMV DNA monitoring was conducted by real-time polymerase chain reaction (PCR) assays. Clinical outcomes of interest were OM and NRM through day 365 after allo-HSCT. The cumulative incidence of CMV DNAemia in this cohort was 52.6%. A total of 306 out of 382 patients with CMV DNAemia received preemptive antiviral therapy (PET). PET use for CMV DNAemia, but not the occurrence of CMV DNAemia, taken as a qualitative variable, was associated with increased OM and NRM in univariate but not in adjusted models. A subcohort analysis including patients monitored by the COBAS Ampliprep/COBAS Taqman CMV Test showed that OM and NRM were comparable in patients in whom either low or high plasma CMV DNA threshold (<500 vs ≥500 IU/mL) was used for PET initiation. In conclusion, CMV DNAemia was not associated with increased OM and NRM in allo-HSCT recipients. The potential impact of PET use on mortality was not proven but merits further research.  相似文献   
2.
VN2222 (1-(benzo[b]thiophen-3-yl)-3-[4-(2-methoxiphenyl piperazin-1-yl]propan-1-ol) is a potential antidepressant with high affinity for the serotonin transporter and 5-HT(1A) receptors. Locally applied, VN2222 enhanced the extracellular 5-hydroxytryptamine (5-HT) concentration (5-HT(ext)) in rat striatum to 780% of baseline whereas its systemic administration (1-10 mg/kg s.c.) reduced 5-HT(ext). In the presence of citalopram, 8-OH-DPAT or VN2222 applied in medial prefrontal cortex reduced 5-HT(ext). Fluoxetine, VN2222, and 8-OH-DPAT suppressed the firing rate of dorsal raphe 5-HT neurons (ED(50): 790, 14.9, and 0.8 microg/kg i.v., respectively). These effects were antagonized by WAY 100635. Administration of VN2222 for 2 weeks desensitized 5-HT(1A) receptors as assessed by microdialysis and single-unit recordings (ED(50) values for 8-OH-DPAT were 0.45 and 2.34 microg/kg i.v. for controls and rats treated with 6 mg/kg day VN2222). These results show that VN2222 is a mixed 5-HT reuptake inhibitor/5-HT(1A) agonist that markedly desensitizes 5-HT(1A) autoreceptors. These properties suggest that it may be a clinically effective dual action antidepressant drug.  相似文献   
3.
4.
INTRODUCTION AND OBJECTIVES: Some authors have described seasonal variations in the incidence of acute myocardial infarction. The aim of this study was to determine the existence of seasonal rhythms in admissions for acute myocardial infarction to coronary care units, and in mortality, and to analyze the influence of age on environmental factors. PATIENTS AND METHOD: The study included a total of 8400 consecutive patients with acute myocardial infarction admitted to 12 coronary care units in the PRIMVAC registry from January 1995 to December 1999. Seasonal rhythms were analyzed with the time series method and the Cosinor regression equation. The influence of age was analyzed with the chi 2 test. RESULTS: The total number of admissions increased in winter and decreased in summer. The highest peak (acrophase) occurred in winter, with 2183 cases (r2=0.91), specifically in February, with 742 cases (r2=0.66). The age of the patients conditioned seasonal variations (P=.006), and the influence was statistically significant for patients over 65 years of age. Changes in mortality with time did not reach statistical significance. CONCLUSIONS: A seasonal rhythm in admissions for acute myocardial infarction was found, with an increase in winter and a decrease in summer. Age conditioned the effect of environmental factors on acute myocardial infarction, and patients aged 65 years or older were more sensitive to mechanisms that led to increases in admissions in winter.  相似文献   
5.
6.
7.
8.
SARS-CoV-2 infection causes an abrupt response by the host immune system, which is largely responsible for the outcome of COVID-19. We investigated whether the specific immune responses in the peripheral blood of 276 patients were associated with the severity and progression of COVID-19. At admission, dramatic lymphopenia of T, B, and NK cells is associated with severity. Conversely, the proportion of B cells, plasmablasts, circulating follicular helper T cells (cTfh) and CD56CD16+ NK-cells increased. Regarding humoral immunity, levels of IgM, IgA, and IgG were unaffected, but when degrees of severity were considered, IgG was lower in severe patients. Compared to healthy donors, complement C3 and C4 protein levels were higher in mild and moderate, but not in severe patients, while the activation peptide of C5 (C5a) increased from the admission in every patient, regardless of their severity. Moreover, total IgG, the IgG1 and IgG3 isotypes, and C4 decreased from day 0 to day 10 in patients who were hospitalized for more than two weeks, but not in patients who were discharged earlier. Our study provides important clues to understand the immune response observed in COVID-19 patients, associating severity with an imbalanced humoral response, and identifying new targets for therapeutic intervention.  相似文献   
9.
Background: Implant therapy is a highly predictable treatment option; however, insufficient data exist to show whether flapless implant surgery provides better esthetic outcomes and less bone loss than implant surgery with a flap approach. Methods: In this randomized, controlled study comparing the flapless and traditional flap protocol for implant placement, 24 patients received a single implant in the anterior maxillary region. A cone beam computed tomography–aided surgical guide was used for implant placement surgery for both groups. Implants were restored using a one‐piece, screw‐retained ceramic crown at 3 months. Radiographic and clinical measurements were assessed at baseline (implant placement) and at 3 (crown placement), 6, 9, and 15 months. Clinical parameters evaluated were plaque index, gingival index, papillary index (PPI) (0 = no papilla, 1 = less than half, 2 = more than half but not complete, 3 = complete fill, and 4 = overfill), marginal tissue levels, biotype, width of keratinized tissue, and soft tissue thickness. Results: Implant success rate was 92% in both groups. Mean PPI values for the flap control group and flapless test group were 2.38 ± 0.51 versus 2.31 ± 0.48 at crown placement (P = 0.68) and 2.52 ± 0.52 versus 2.64 ± 0.54 at 15 months (P = 0.42), respectively. PPI increased over time in both groups, although the flapless group had a significantly larger change in PPI from crown placement to 6 and 9 months (P <0.01). Crestal bone levels in the flap group were more apical in relation to the implant platform than those in the flapless group for the duration of the study. No differences among groups were noted for all other measurements. Conclusions: Both flapless and flap implant placement protocols resulted in high success rates. A flapless protocol may provide a better short‐term esthetic result, although there appears to be no long‐term advantage.  相似文献   
10.
The aim of this study was to characterize timing, kinetic, and magnitude of CMV‐specific immune response after hematopoietic stem cell transplantation (HSCT) and its ability to predict CMV replication and clinical outcomes. Using cell surface and intracellular cytokine staining by flow cytometry, CMV‐specific T‐cell response was measured in blood, while CMV viral load and chimerism were determined by real‐time PCR. Patients that reconstituted CMV‐specific T‐cell response within 6 weeks after Allo‐SCT showed a more robust immune response (CD8+: 0.7 cells/μl vs. 0.3/μl; P‐value = 0.01), less incidence of CMV replication (33% vs. 89.5%; P‐value = 0.007), reduced viral loads (1.81 log copies/ml vs. 0 copies/ml; P‐value = 0.04), and better overall survival (72%; CI: 0.53–0.96 vs. 42% CI: 0.24–0.71; P‐value = 0.07) than patients with a delayed immune reconstitution. Viremic patients had significantly higher transplant‐related mortality than nonviremic patients after 1 year (33% CI: 0.15–0.52 vs. 0% CI: 0.05–0.34; P‐value = 0.01). Risk factors independently associated with viral replication were receptor pretransplant CMV‐positive serostatus (P‐value = 0.02) and acquiring CMV‐specific T‐cell response after 6 weeks post‐transplantation (P‐value = 0.009). In conclusion, timing of acquiring a positive CMV‐specific T‐cell immune response after transplantation may identify patients with different risk for viral replication and different clinical outcomes, including survival.  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