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   3017篇
  免费   159篇
  国内免费   18篇
耳鼻咽喉   20篇
儿科学   76篇
妇产科学   106篇
基础医学   311篇
口腔科学   69篇
临床医学   296篇
内科学   884篇
皮肤病学   54篇
神经病学   146篇
特种医学   47篇
外科学   545篇
综合类   69篇
预防医学   195篇
眼科学   74篇
药学   169篇
中国医学   12篇
肿瘤学   121篇
  2023年   27篇
  2022年   75篇
  2021年   118篇
  2020年   55篇
  2019年   92篇
  2018年   107篇
  2017年   58篇
  2016年   85篇
  2015年   80篇
  2014年   117篇
  2013年   129篇
  2012年   219篇
  2011年   213篇
  2010年   118篇
  2009年   114篇
  2008年   172篇
  2007年   186篇
  2006年   162篇
  2005年   179篇
  2004年   164篇
  2003年   135篇
  2002年   120篇
  2001年   38篇
  2000年   29篇
  1999年   29篇
  1998年   24篇
  1997年   16篇
  1996年   23篇
  1995年   15篇
  1994年   8篇
  1993年   12篇
  1992年   27篇
  1991年   26篇
  1990年   23篇
  1989年   11篇
  1988年   24篇
  1987年   16篇
  1986年   13篇
  1985年   7篇
  1984年   8篇
  1980年   6篇
  1979年   6篇
  1978年   6篇
  1977年   9篇
  1974年   7篇
  1973年   8篇
  1972年   6篇
  1971年   9篇
  1968年   13篇
  1967年   10篇
排序方式: 共有3194条查询结果,搜索用时 15 毫秒
21.
ObjectivesPrevious work on high-sensitivity troponin I (hs-cTnI) has demonstrated that it may identify patients with stable cardiovascular disease (CVD) at risk for future myocardial infarction (MI). In this study, we assessed if hs-cTnT concentrations could also identify those stable CVD patients at high risk for future MI and other ischemic cardiac outcomes.Methodshs-cTnT (lot:153-401) was measured in specimens obtained at randomisation in the Heart Outcomes Prevention Evaluation (HOPE) study (n = 2941 stable CVD patients, 4.5 years follow-up). The primary outcome for the HOPE study (MI, stroke, or cardiovascular death) was used to identify cutoffs by receiver operating characteristic (ROC) curve analysis and was used in conjunction with the 95th and 99th percentile upper limits to construct different concentration ranges, which were assessed using log-rank tests and multivariable Cox proportional hazard models. These different concentration ranges were then assessed for the components of the primary outcome and for heart failure (HF).ResultsThe ROC derived hs-cTnT cutoff was 8 ng/L for the primary outcome. Subjects with hs-cTnT either below (8 to < 14 ng/L) or slightly above the published 99th from a healthy population (14 to 21 ng/L) had similar probability for the primary outcome. Those with hs-cTnT concentrations > 31 ng/L had the highest probability and greatest risk for future MI, HF, and cardiovascular death as compared to those with hs-cTnT concentrations < 8 ng/L.ConclusionIn patients with stable CVD disease hs-cTnT measurement identifies those at risk for MI as well as HF and cardiovascular death.  相似文献   
22.
GeroScience - A complex picture of factors influencing cognition is necessary to be drawn for a better understanding of the role of potentially modifiable factors in dementia. The aim was to assess...  相似文献   
23.
Objectives: Paramedics' decision to terminate field resuscitation without a physician present may depend on personal and external factors. This study investigates factors associated with paramedic psychological comfort with termination of resuscitation (TOR) to inform future training. Methods: We administered an anonymous survey to all practicing paramedics in a large urban Asian Emergency Medical Services system where formal TOR training had not yet been conducted and field TOR was not routinely applied. The survey assessed psychological comfort using the validated Psychological Comfort Total (PCT) scale (summed score of 28 items, with higher scores representing greater comfort). We examined scores associated with four personal (prior resolution of personal loss, knowledge of survival probability, religious affiliation and experience with death pronouncements) and two external (location of patient and perceived trust of family) factors. Data were entered into Excel and analyzed by t-tests and ANOVA. Results: Response rate was 73.6% (254/345). Respondents were 30.3 years (mean, SD 7.1) with 7.2 years (mean, SD 5.54) of practice experience. Over 60% had been involved in 6 or more field death pronouncements in the prior 12 months. Higher PCT scores were associated with prior resolution of personal loss and knowledge of survival probability. Lower PCT scores were associated with patient location in a public place and perceived family lack of trust. PCT scores were not associated with paramedic religious affiliation or number of prior death pronouncements. Conclusions: Paramedic psychological comfort with field death pronouncement is associated with personal and external factors. Since paramedic comfort is important for protocol adoption, TOR education should target not only knowledge, but also public arena management, communication skills for engaging with families, and help paramedics resolve prior personal loss.  相似文献   
24.
Thrombotic microangiopathies (TMAs) are rare, but life-threatening disorders characterized by microangiopathic hemolytic anemia and thrombocytopenia (MAHAT) associated with multiorgan dysfunction as a result of microvascular thrombosis and tissue ischemia. The differentiation of the etiology is of utmost importance as the pathophysiological basis will dictate the choice of appropriate treatment.We retrospectively evaluated 154 (99 females and 55 males) patients who received therapeutic plasma exchange (TPE) due to a presumptive diagnosis of TMA, who had serum ADAMTS13 activity/anti-ADAMTS13 antibody analysis at the time of hospital admission. The median age of the study cohort was 36 (14-84). 67 (43.5%), 32 (20.8%), 27 (17.5%) and 28 (18.2%) patients were diagnosed as thrombotic thrombocytopenic purpura (TTP), infection/complement-associated hemolytic uremic syndrome (IA/CA-HUS), secondary TMA and TMA-not otherwise specified (TMA-NOS), respectively. Patients received a median of 18 (1­75) plasma volume exchanges for 14 (153) days. 81 (52.6%) patients received concomitant steroid therapy with TPE. Treatment responses could be evaluated in 137 patients. 90 patients (65.7%) achieved clinical remission following TPE, while 47 (34.3%) patients had non-responsive disease. 25 (18.2%) non-responsive patients died during follow-up. Our study present real-life data on the distribution and follow-up of patients with TMAs who were referred to therapeutic apheresis centers for the application of TPE.  相似文献   
25.
Multi‐state models are useful for modelling disease progression where the state space of the process is used to represent the discrete disease status of subjects. Often, the disease process is only observed at clinical visits, and the schedule of these visits can depend on the disease status of patients. In such situations, the frequency and timing of observations may depend on transition times that are themselves unobserved in an interval‐censored setting. There is a potential for bias if we model a disease process with informative observation times as a non‐informative observation scheme with pre‐specified examination times. In this paper, we develop a joint model for the disease and observation processes to ensure valid inference because the follow‐up process may itself contain information about the disease process. The transitions for each subject are modelled using a Markov process, where bivariate subject‐specific random effects are used to link the disease and observation models. Inference is based on a Bayesian framework, and we apply our joint model to the analysis of a large study examining functional decline trajectories of palliative care patients. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
26.
Journal of Thrombosis and Thrombolysis -  相似文献   
27.
Extracts of tumors from patients with humoral hypercalcemia of malignancy (HHM) were tested using an in vitro bone resorption assay in order to investigate the pathogenesis of the hypercalcemia. Bone resorption was assessed by comparing the percent release of previously incorporated 45Ca from paired halves of newborn mouse calvaria. Saline extracts of three out of five tumors from HHM patients caused a significant increase in 45Ca release relative to controls. Extracts of liver and non-HHM tumor did not cause significant resorption. Tumor-stimulated bone resorption was blocked by indomethacin and eicosatetraynoic acid, inhibitors of the synthesis of prostaglandins (PGs) and related metabolites of arachidonic acid, whereas resorption stimulated by parathyroid hormone (PTH), PGE2, or 1,25-(OH)2D3 was not. Furthermore, levels of immunoreactive PTH or PGE2 in tumor extracts were not sufficient to account for the degree of resorption observed. These observations indicate that PTH or PGE2 are not responsible for the bone resorption caused by extracts of tumors from these patients with HHM. Furthermore, they suggest that hypercalcemia in these patients may result from bone resorption stimulated by the local production in bone of PGs or related metabolites of arachidonic acid in response to a humoral factor elaborated by the tumor.  相似文献   
28.
Early clinical studies investigating the role of angiotensin-converting enzyme (ACE) inhibitors in the treatment of heart failure unexpectedly demonstrated a possible reduction in coronary heart disease endpoints. Two large scale clinical trials, HOPE and EUROPA, both studies in patients with coronary artery disease (CAD) but without clinical evidence of heart failure, showed a highly significant improvement in coronary heart disease outcomes on treatment with ramipril and perindopril, respectively, in contrast, in a similar population, PEACE was unable to demonstrate such benefit with trandolapril. Meta-analyses of all trials involving ACE-inhibitors showed a highly significant improvement in coronary heart disease endpoints. Current ESC guidelines recommend ACE-inhibitor therapy in CAD patients with co-existing indications for ACE-inhibitors, such as hypertension, heart failure, left ventricular dysfunction, prior MI was left ventricular dysfunction, or diabetes (class I, level of evidence A). These guidelines also recommend ACE-inhibitor therapy in all patients with angina and proven coronary disease (class IIa, level of evidence B). However, in angina patients without independent indication for ACE-inhibitor treatment, the anticipated benefit should be weighted against the costs and risks of side effects; in these patients, only agents and doses of proven efficacy for secondary prevention should be employed.  相似文献   
29.
30.
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