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   706篇
  免费   42篇
  国内免费   3篇
耳鼻咽喉   26篇
儿科学   50篇
妇产科学   21篇
基础医学   83篇
口腔科学   5篇
临床医学   46篇
内科学   176篇
皮肤病学   10篇
神经病学   29篇
特种医学   16篇
外科学   106篇
综合类   15篇
一般理论   1篇
预防医学   50篇
眼科学   14篇
药学   52篇
中国医学   5篇
肿瘤学   46篇
  2023年   2篇
  2022年   11篇
  2021年   32篇
  2020年   13篇
  2019年   15篇
  2018年   23篇
  2017年   21篇
  2016年   17篇
  2015年   17篇
  2014年   25篇
  2013年   38篇
  2012年   63篇
  2011年   66篇
  2010年   32篇
  2009年   38篇
  2008年   44篇
  2007年   48篇
  2006年   52篇
  2005年   33篇
  2004年   38篇
  2003年   40篇
  2002年   33篇
  2001年   6篇
  2000年   4篇
  1999年   3篇
  1998年   2篇
  1997年   5篇
  1996年   3篇
  1995年   2篇
  1994年   3篇
  1993年   1篇
  1992年   2篇
  1991年   6篇
  1990年   3篇
  1989年   4篇
  1988年   2篇
  1986年   1篇
  1982年   1篇
  1978年   1篇
  1976年   1篇
排序方式: 共有751条查询结果,搜索用时 15 毫秒
1.
2.
3.
Conclusion  The ACCF/ASNC AC for SPECT MPI provides recommendations for the appropriate use of SPECT MPI. After the publication of the AC document in 2005, the AC has been used by nuclear cardiology practices with many clinical studies evaluating the list of indications in routine clinical practice. From these data. ASNC recommends minor but important changes to the indication list, suggesting the addition of 6 new indications and the modification of the definitions for “chest pain syndrome” and “CHD high risk.”. An objective review of existing indications focused on only those indications that had significant variability among the reviewers (n=20). These indications were reviewed in the presence of existing and new evidence-based data, and ASNC recommends that the grades for 6 indications be re-evaluated. The AC for SPECT MPI will require periodic review as new evidence becomes available or as clinical practice evolves. ASNC recognizes the importance of these criteria to improve the quality of patient care, and it will continue to play a key role in assembling the information for this ongoing review. From the current summary of evidence, ASNC consensus opinions, and ASNC recommendations in this document, ASNC strongly recommends that the AC guidelines be reviewed Prepared by the American Society of Nuclear Cardiology Quality Assurance Subcommittee for Quality in Imaging Standards. Reviewed by members of the American Society of Nuclear Cardiology Quality Assurance Committee. Approved by the American Society of Nuclear Cardiology Board of Directors, September 6, 20.  相似文献   
4.
A multicolour tandem labelling fluorescence in situ hybridization(FISH) procedure was used to compare the frequencies of radiation-inducedchromosome breakage and hyperdiploidy of chromosome 1 occurringin non-cultured granulocytes and Go lymphocytes with those observedin cultured metaphase and interphase lymphocytes. Whole blood,obtained from healthy male donors, was exposed in vitro to 0,100, 200, 300 and 400 cGy of ionizing radiation from a 137Cssource. Aliquots containing granulocytes and Go lymphocytesfrom each dose were treated immediately with hypotonic KCl onice and harvested. Cells were hybridized with  相似文献   
5.
The present study compared the recently developed multilocus sequence typing (MLST) approach with a well-established molecular typing technique, pulsed-field gel electrophoresis (PFGE), for subspecies differentiation of Enterococcus faecalis isolates. We sequenced intragenic regions of three E. faecalis antigen-encoding genes (ace, encoding a collagen and laminin adhesin; efaA, encoding an endocarditis antigen; and salA, encoding a cell wall associated antigen) and one housekeeping gene (pyrC) of 22 E. faecalis isolates chosen largely for their temporal and geographical diversity, but also including some outbreak isolates. MLST analysis of polymorphic regions of these four genes identified 13 distinct sequence types (STs) with different allelic profiles; the composite sequences generated from the four sequenced gene fragments of individual isolates showed 98.3 to 100% identity among the 22 isolates. We also found that the allelic profiles from two sequences, ace and salA, were sufficient to distinguish all 13 STs of this study. The 13 STs corresponded to 12 different PFGE types, with one previously designated PFGE clone (a widespread U.S. clone of beta-lactamase-producing isolates) being classified into two highly related STs which differed at 2 of 2,894 bases, both in the same allele. MLST also confirmed the clonal relationships among the isolates of two other PFGE clonal groups, including vancomycin resistant isolates. Thus, this pilot study with representative E. faecalis isolates suggests that, similar to PFGE, the sequence-based typing method may be useful for differentiating isolates of E. faecalis to the subspecies level in addition to identifying outbreak isolates.  相似文献   
6.
7.
OBJECTIVE: To determine the extent to which daily stress and mood are associated with pain, health-care use, and school activity in adolescents with sickle cell disease (SCD). METHOD: Adolescents with SCD (n = 37; aged 13 to 17 years) completed daily diaries assessing pain, stress, mood, activity, and health-care use for up to 6 months. Multilevel modeling was used to analyze the data. RESULTS: Daily increases in stress and negative mood were associated with increases in same-day pain, health-care use, and reductions in school and social activity. Increases in positive mood were associated with decreases in pain, less health-care use, and more activity participation. Notably, pain was predictive of higher stress and lower positive mood on subsequent days. CONCLUSION: Pain in adolescents with SCD is stressful and may lead to alterations in mood states. Understanding the way in which these variables relate to health-care use and activity may lead to improved pain management approaches.  相似文献   
8.
Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is spreading at a rapid pace, and the World Health Organization declared it as pandemic on 11 March 2020. Mycoplasma pneumoniae is an "atypical" bacterial pathogen commonly known to cause respiratory illness in humans. The coinfection from SARS-CoV-2 and mycoplasma pneumonia is rarely reported in the literature to the best of our knowledge. We present a study in which 6 of 350 patients confirmed with COVID-19 were also diagnosed with M. pneumoniae infection. In this study, we described the clinical characteristics of patients with coinfection. Common symptoms at the onset of illness included fever (six [100%] patients); five (83.3%) patients had a cough, shortness of breath, and fatigue. The other symptoms were myalgia (66.6%), gastrointestinal symptoms (33.3%-50%), and altered mental status (16.7%). The laboratory parameters include lymphopenia, elevated erythrocyte sedimentation rate, C-reactive protein, lactate dehydrogenase, interleukin-6, serum ferritin, and D-dimer in all six (100%) patients. The chest X-ray at presentation showed bilateral infiltrates in all the patients (100%). We also described electrocardiogram findings, complications, and treatment during hospitalization in detail. One patient died during the hospital course.  相似文献   
9.
10.
Spontaneous intracerebral hemorrhage (ICH) often represents a devastating event despite maximal therapeutic efforts. Statins are drugs primarily used as cholesterol reducers with several pleiotropic effects that may result in neuroprotection. In this study, we assessed the continued use of statins after acute ICH. From January 2008 to October 2010, we analyzed a retrospective cohort of 178 patients with acute ICH. Patients with head injury, cerebral tumors, hemorrhage after ischemic stroke, and having a National Institute Health Stroke Scale (NIHSS) score of greater than 30 points on admission were excluded. In 29 patients, statins were continued within the first 24 h after onset of ICH and, subsequently, given daily until discharge, whereas 149 nonusers were used as controls. Inpatient mortality, NIHSS, and Glasgow Outcome Score (GOS) at discharge as well as mortality after 10 days, 3 months, and 6 months were recorded as outcomes. Additionally, changes of C-reactive protein (CRP) and white blood cell (WBC) counts, as well as aspartate transaminase and alanine transaminase levels were assessed. Except for the number of hypertensive and diabetic patients, characteristics on admission were similar between both groups. No mortality was observed in statin users, whereas 19 controls (12.7 %) died (p?=?0.04) until discharge; after 10 days, 3 months, and 6 months, a similar trend was found. After 6 months, statin use was associated to lower mortality in regression models (OR?=?0.32, 95 % CI?=?0.11–0.95, p?=?0.04). In the same way, statin use was related to NIHSS reduction (?3.53, 95 % CI?=??7.59 to 0.42, p?=?0.07). In mixed models, changes of WBC counts and CRP levels were associated with statin use. The hepatic enzymes were similar between groups. The continued use of statins after ICH could be associated to early neurological improvement and may reduce mortality within 6 months. Immunomodulation as a pleiotropic effect of statins may represent one of the underlying mechanisms.  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