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   2215篇
  免费   124篇
  国内免费   9篇
耳鼻咽喉   6篇
儿科学   56篇
妇产科学   15篇
基础医学   411篇
口腔科学   43篇
临床医学   198篇
内科学   454篇
皮肤病学   23篇
神经病学   141篇
特种医学   291篇
外科学   185篇
综合类   31篇
预防医学   134篇
眼科学   144篇
药学   120篇
中国医学   2篇
肿瘤学   94篇
  2022年   14篇
  2021年   34篇
  2020年   14篇
  2019年   22篇
  2018年   26篇
  2017年   29篇
  2016年   23篇
  2015年   40篇
  2014年   54篇
  2013年   60篇
  2012年   91篇
  2011年   68篇
  2010年   67篇
  2009年   53篇
  2008年   86篇
  2007年   67篇
  2006年   69篇
  2005年   82篇
  2004年   72篇
  2003年   64篇
  2002年   74篇
  2001年   58篇
  2000年   48篇
  1999年   47篇
  1998年   55篇
  1997年   69篇
  1996年   59篇
  1995年   59篇
  1994年   53篇
  1993年   40篇
  1992年   44篇
  1991年   39篇
  1990年   30篇
  1989年   41篇
  1988年   52篇
  1987年   38篇
  1986年   51篇
  1985年   47篇
  1984年   31篇
  1983年   35篇
  1982年   29篇
  1981年   26篇
  1980年   26篇
  1979年   25篇
  1978年   18篇
  1977年   25篇
  1976年   25篇
  1975年   21篇
  1973年   12篇
  1969年   11篇
排序方式: 共有2348条查询结果,搜索用时 0 毫秒
1.
2.
3.
Ruggieri  PM; Laub  GA; Masaryk  TJ; Modic  MT 《Radiology》1989,171(3):785-791
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.  相似文献   
4.
5.
Operative mortality, postoperative morbidity and follow up data were analyzed retrospectively from 122 consecutive patients, over 65 years old undergoing elective aortocoronary bypass grafting for symptomatic relief of angina pectoris at the Plains Health Centre, Regina, Saskatchewan, from January 1980 to December 1985. There were two in-hospital deaths (operative mortality 1.6%). Definite perioperative myocardial infarction occurred in 12 patients (9.8%). The 120 survivors were followed for a mean of 32 months. There were three deaths during follow-up, giving a five-year probability of survival of 93%. Twenty-three clinical events (including deaths) occurred during follow-up, giving a five-year probability of event free survival of 72%. Ninety percent of patients say they are pleased with their operation. Seventy-eight percent are currently angina free. These data illustrate the effectiveness of aortocoronary bypass grafting in low risk elderly patients with symptomatic coronary artery disease.  相似文献   
6.
7.
8.
9.
Early intervention with budesonide is an effective strategy for mild persistent asthma, which has been shown to provide additional clinical benefits at a low incremental cost using USA cost data. The present authors analysed whether this strategy would be cost-effective using cost data for other countries. Based on the 3-yr prospective, randomised, double-blind inhaled Steroid Treatment As Regular Therapy (START) in early asthma study (comparing budesonide and placebo combined with usual asthma therapy), the cost-effectiveness was estimated separately for eight different countries, from both healthcare payer and societal perspectives, of adding budesonide to usual asthma therapy. Local unit costs were applied to data for the total trial population. Incremental cost-effectiveness ratios (ICER) were estimated as cost per symptom-free day (SFD) gained. Budesonide increased SFDs by an average of 14.1 days annually. From a healthcare payer perspective, budesonide would reduce the total cost of asthma care in Australia. In Sweden, Canada, France, Spain, UK, China and the USA, the ICER ranged from US$2.4-11.3 per SFD. From a societal perspective, budesonide would be cost-saving in Australia, Canada and Sweden. In conclusion, for countries where costs with budesonide are higher, the policy implication has to be determined by that health system's willingness to pay for an additional symptom-free day. However, where budesonide therapy increases symptom-free days and reduces total costs, the policy conclusion clearly favours early intervention.  相似文献   
10.
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