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   442篇
  免费   30篇
  国内免费   1篇
耳鼻咽喉   1篇
儿科学   11篇
妇产科学   3篇
基础医学   53篇
口腔科学   8篇
临床医学   34篇
内科学   51篇
皮肤病学   7篇
神经病学   28篇
特种医学   16篇
外科学   131篇
综合类   7篇
一般理论   1篇
预防医学   18篇
眼科学   21篇
药学   23篇
肿瘤学   60篇
  2023年   5篇
  2022年   6篇
  2021年   16篇
  2020年   5篇
  2019年   13篇
  2018年   12篇
  2017年   5篇
  2016年   8篇
  2015年   8篇
  2014年   12篇
  2013年   23篇
  2012年   29篇
  2011年   30篇
  2010年   20篇
  2009年   17篇
  2008年   23篇
  2007年   18篇
  2006年   15篇
  2005年   12篇
  2004年   18篇
  2003年   14篇
  2002年   16篇
  2001年   19篇
  2000年   12篇
  1999年   12篇
  1998年   5篇
  1997年   7篇
  1995年   2篇
  1994年   6篇
  1993年   4篇
  1992年   10篇
  1991年   10篇
  1990年   4篇
  1989年   4篇
  1988年   5篇
  1987年   7篇
  1986年   5篇
  1985年   8篇
  1984年   2篇
  1983年   5篇
  1982年   1篇
  1981年   3篇
  1980年   2篇
  1979年   4篇
  1978年   3篇
  1974年   3篇
  1972年   1篇
  1970年   1篇
  1969年   1篇
  1966年   1篇
排序方式: 共有473条查询结果,搜索用时 15 毫秒
1.
2.
Norepinephrine triggers release of glial ATP to increase postsynaptic efficacy   总被引:10,自引:0,他引:10  
Glial cells actively participate in synaptic transmission. They clear molecules from the synaptic cleft, receive signals from neurons and, in turn, release molecules that can modulate signaling between neuronal elements. Whether glial-derived transmitters can contribute to enduring changes in postsynaptic efficacy, however, remains to be established. In rat hypothalamic paraventricular nucleus, we demonstrate an increase in the amplitude of miniature excitatory postsynaptic currents in response to norepinephrine that requires the release of ATP from glial cells. The increase in quantal efficacy, which likely results from an insertion of AMPA receptors, is secondary to the activation of P2X(7) receptors, an increase in postsynaptic calcium and the activation of phosphatidylinositol 3-kinase. The gliotransmitter ATP, therefore, contributes directly to the regulation of postsynaptic efficacy at glutamatergic synapses in the CNS.  相似文献   
3.
PURPOSE: Whole-body 18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) imaging before and after induction therapy was prospectively evaluated in patients with esophageal cancer to determine whether changes in PET images could measure response to therapy. PATIENTS AND METHODS: Between April 1997 and April 1999, 39 patients (34 men and five women; median age, 59 years; range, 36 to 76 years) with esophageal cancer were prospectively enrolled in a single-institution clinical trial of staging, including PET, induction therapy, restaging including PET, and esophagectomy. All patients undergoing esophagectomy after induction therapy (n = 17) were followed either to recurrence, to death, or through a disease-free interval of at least 24 months. RESULTS: PET after standard staging studies and before therapy imaged undetected sites of metastatic disease in six patients (15%). Restaging (including PET) after induction therapy did not identify any patients with disease progression or any patients with loco-regionally unresectable disease at exploration. The median decrease in the standardized uptake value (SUV) during induction therapy was 59%. After R0 esophagectomy, the 2-year disease-free and overall survival was 38% and 63%, respectively, among patients who had a less than 60% decrease in SUV, and 67% and 89%, respectively, among patients who had a greater than 60% decrease in SUV (P =.055 and P =.088, respectively). CONCLUSION: Compared with conventional imaging, PET detects additional sites of metastatic disease at initial evaluation. After induction therapy, PET did not add to the estimation of loco-regional resectability and did not detect new distant metastases. However, changes in [18F]FDG PET may predict disease-free and overall survival after induction therapy and resection in patients with esophageal cancer. Further evaluation in larger trials is warranted.  相似文献   
4.
Secondary cutaneous dissemination from an orbital diffuse large B cell lymphoma has not been described before. The authors report an unusual case of anaplastic variant of diffuse large B cell lymphoma which primarily presented in the orbit and during the course of disease had subcutaneous dissemination.  相似文献   
5.
BackgroundPleomorphic Lobular Carcinoma in Situ (PLCIS) is a pathological variant of Lobular Carcinoma in Situ (LCIS) with distinct features. Since first described over a decade ago there are only few papers published about this condition.MethodsMedline and Pubmed based literature overview was done with the aim of describing the different histopathological, radiological and clinical features of this pathological entity to highlight the different clinicopathological presentations and modalities of treatment described.ResultsPLCIS has different biological features when compared to LCIS. It is more likely to be associated with invasive disease and the immuno-histochemical profile shows it is less likely to be ER and PR positive with higher positivity of HER2, Ki-67and p53. It has been suggested that PLCIS should be treated more aggressively than LCIS and surgically excised in similar fashion to DCIS.ConclusionPLCIS is a more aggressive variant of LCIS that needs to be managed differently. Surgical excision with clear margins is advised. Further adjuvant treatments have been described in the literature with little evidence to support their use.  相似文献   
6.

Background

Emergency departments see uniquely large numbers of patients across all demographic groups who are more likely to smoke and who attend with acute health concerns that can provide an impetus for behaviour change. Despite this potential opportunity, no smoking cessation programme in any UK emergency department yet exists. This study sought to identify perceived barriers and facilitators for emergency department smoking cessation activity, as well as potential modes of intervention, by exploring staff attitudes.

Methods

16 members of staff from the Emergency Department, Derby NHS Teaching Hospital were purposively sampled to include a spectrum of clinical and non-clinical roles, grades, and employment duration. Semi-structured interviews were conducted within the department, and thematically analysed with dual-coding for validity under an interpretivist paradigm.

Findings

Three themes were identified: roles of emergency departments, effects of smoking, and scope for intervention. Effects were described in individual-health and department-management contexts, with belief that reducing patient smoking would benefit both. Health promotion was seen as theoretically part of, and practically achievable within, the emergency department role. Lack of organisational support was a key barrier. Staff practice included occasional ad-hoc smoking cessation activity, but nothing routine. Those who did not incorporate smoking cessation into their practice felt that lack of training and support, rather than time, stopped them from doing so.

Interpretation

Support for emergency department smoking cessation was found in the face of major barriers. Options to address these barriers were suggested, highlighting a willingness to engage. Complex interventions appeared impractical, and no single approach seemed universally applicable to emergency department environments. This study addresses the paucity of evidence around emergency department attitudes towards smoking cessation by providing a unique and in-depth picture of staff in the study department. It also balances clinical and population health viewpoints and has potential to inform promising prevention strategies in the emerging population-focused health-care structures. However, the study might not be generalisable to other emergency departments. Further research exploring patient attitudes would be a valuable next step.

Funding

Health Education East Midlands.  相似文献   
7.
8.
This study looks at toxicity and survival data when chemoradiation (CRT) is delivered using intensity‐modulated radiation therapy (IMRT) after induction chemotherapy. Forty‐one patients with esophageal adenocarcinoma treated with IMRT from March 2007 to May 2009 at Memorial Sloan‐Kettering Cancer Center were analyzed. All patients received induction chemotherapy prior to CRT. Thirty‐nine percent (n = 16) of patients underwent surgical resection less than 4 months after completing CRT. Patients were predominantly male (78%), with a median age of 68 years (range 32–85 years). The majority of acute treatment‐related toxicity was hematologic or gastrointestinal, with 17% of patients having grade 3+ hematologic toxicity and 12% of patients having grade 3+ gastrointestinal toxicity. Only two patients developed grade 2–3 pneumonitis (5%) and 5 patients experienced post‐operative pulmonary complications (29%). Eight patients (20%) required a treatment break. With a median follow up of 41 months for surviving patients, 2‐year overall survival was 61%, and the cumulative incidences of local failure (LF) and distant metastases were 40% and 51%, respectively. This rate of LF was reduced to 13% in patients who underwent surgical resection. Surgery and younger age were significant predictors of decreased time to LF on univariate analysis. Induction chemotherapy followed by CRT using IMRT in the treatment of esophageal cancer is well tolerated and is not associated with an elevated risk of postoperative pulmonary complications. The use of IMRT may allow for integration of more intensified systemic therapy or radiation dose escalation for esophageal adenocarcinoma, ultimately improving outcomes for patients with this aggressive disease.  相似文献   
9.
Allergic bronchopulmonary aspergillosis (ABPA) is caused by an exaggerated T(H)2 response to the ubiquitous mold Aspergillus fumigatus. ABPA develops in a small fraction of patients with cystic fibrosis and asthma, suggesting that intrinsic host defects play a major role in disease susceptibility. This article reviews current understanding of the immunopathology, clinical and laboratory findings, and diagnosis and management of ABPA. It highlights clinical and laboratory clues to differentiate ABPA from cystic fibrosis and asthma, which are challenging given clinical and serologic similarities. A practical diagnostic algorithm and management scheme to aid in the treatment of these patients is outlined.  相似文献   
10.

Background

Systemic inflammation and increased matrix metalloproteinase (MMP) cause elastin degradation leading to abdominal aortic aneurysm (AAA) expansion. Several prospective studies report that statin therapy can reduce AAA expansion through anti-inflammation. We hypothesize that monocyte activity plays a pivotal role in this AAA development and this study examines patient peripheral blood monocyte cell adhesion, transendothelial migration, and MMP concentrations between AAA and non-AAA patients.

Materials and methods

Peripheral blood was collected and monocytes isolated from control (n = 15) and AAA (n = 13) patients. Monocyte adhesion, transmigration, and permeability assays were assessed. Luminex assays determined MMP-9 and tissue inhibitor of metalloproteinase-4 (TIMP-4) concentrations from cell culture supernatant and patient serum.

Results

AAA patient monocytes showed increased adhesion to the endothelium relative fluorescence units (RFU, 0.33 ± 0.17) versus controls (RFU, 0.13 ± 0.04; P = 0.005). Monocyte transmigration was also increased in AAA patients (RFU, 0.33 ± 0.11) compared with controls (RFU, 0.25 ± 0.04, P = 0.01). Greater numbers of adhesive (R2 = 0.66) and transmigratory (R2 = 0.86) monocytes were directly proportional to the AAA diameter. Significantly higher serum levels of MMP-9 (2149.14 ± 947 pg/mL) were found in AAA patients compared with controls (1189.2 ± 293; P = 0.01). TIMP-4 concentrations were significantly lower in AAA patients (826.7 ± 100 pg/mL) compared with controls (1233 ± 222 pg/mL; P = 0.02). Cell culture supernatant concentrations of MMP and TIMP from cocultures were higher than monocyte-only cultures.

Conclusions

Monocytes from AAA patients have greater adhesion and transmigration through the endothelium in vitro, leading to elevated MMP-9 levels and the appropriate decrease in TIMP-4 levels. The ability to modulate monocyte activity may lead to novel medical therapies to decrease AAA expansion.  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