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   5712篇
  免费   533篇
  国内免费   9篇
耳鼻咽喉   72篇
儿科学   195篇
妇产科学   162篇
基础医学   810篇
口腔科学   57篇
临床医学   755篇
内科学   988篇
皮肤病学   109篇
神经病学   644篇
特种医学   111篇
外科学   563篇
综合类   48篇
一般理论   6篇
预防医学   702篇
眼科学   324篇
药学   334篇
中国医学   3篇
肿瘤学   371篇
  2024年   16篇
  2023年   127篇
  2022年   164篇
  2021年   425篇
  2020年   268篇
  2019年   337篇
  2018年   333篇
  2017年   273篇
  2016年   289篇
  2015年   236篇
  2014年   320篇
  2013年   363篇
  2012年   465篇
  2011年   487篇
  2010年   234篇
  2009年   209篇
  2008年   296篇
  2007年   247篇
  2006年   226篇
  2005年   214篇
  2004年   165篇
  2003年   190篇
  2002年   158篇
  2001年   24篇
  2000年   10篇
  1999年   11篇
  1998年   33篇
  1997年   12篇
  1996年   12篇
  1995年   7篇
  1994年   7篇
  1993年   5篇
  1992年   4篇
  1991年   6篇
  1990年   7篇
  1989年   7篇
  1987年   7篇
  1986年   3篇
  1985年   6篇
  1984年   3篇
  1983年   5篇
  1982年   3篇
  1980年   4篇
  1979年   3篇
  1975年   2篇
  1973年   7篇
  1972年   4篇
  1970年   3篇
  1969年   2篇
  1967年   2篇
排序方式: 共有6254条查询结果,搜索用时 312 毫秒
11.
12.
13.
14.
15.
OBJECTIVES: Studies of emergency department (ED) pain management in patients with trauma have been mostly restricted to patients with fractures, yet the potential for undertreatment of more severely injured patients is great. The authors sought to identify factors associated with failure to receive ED opioid administration in patients with acute trauma who subsequently required hospitalization. METHODS: At an urban Level 1 trauma center and teaching hospital, a retrospective cohort study of trauma team activation patients requiring hospitalization between January 1 and December 31, 1999, was conducted. The authors excluded patients receiving opioids only within ten minutes of chest tube insertion or fracture manipulation. The main outcome measure was ED opioid administration. RESULTS: A total of 540 charts of hospitalized first-tier trauma team activation patients were reviewed. A total of 258 (47.8%) received intravenous opioid analgesia within three hours of ED arrival. The median time to receiving the first dose of opioids was 95 minutes. Patients were independently less likely to receive opioids if they were younger or older, were intubated, had a lower Revised Trauma Score, or did not require fracture manipulation. Patients with these factors were less likely to receive opioids independent of the amount of time they spent in the ED. CONCLUSIONS: Many trauma activation patients requiring hospitalization do not receive opioid analgesia in the ED. Patients at particular risk for oligoanalgesia include those who are younger or older and those who are more seriously injured, as defined by a lower Revised Trauma Score, lower Glasgow Coma Scale score, and intubation.  相似文献   
16.
BACKGROUND: Development of an acclimation protocol for use when measuring resting energy expenditure (REE) would simplify and standardize data collection. The purpose of this study was to determine if our 2 metabolic carts could be used interchangeably and to determine if excluding the first 3 or 5 minutes of data collected as an acclimation period would significantly improve the coefficients of variation (CVs) for oxygen consumed (VO(2)) and carbon dioxide produced (VCO(2)) when performing REE assessments with our metabolic cart systems. METHODS: Thirteen healthy, nonsmoking adults ranging in age from 32 to 45 years, with activity levels ranging from sedentary to highly active, participated. Indirect calorimetry was performed twice in the morning after 30 minutes of supine resting. Subjects had fasted for 12 hours, and did not exercise within the last 24 hours. The system order for testing was randomized for the first measurement. When the first measurement was completed, subjects were crossed over for measurement using a second metabolic cart. RESULTS: The CVs for VO(2) and VCO(2) were significantly lower when excluding the first 3 (VO(2), p = .0005), (VCO(2), p = .0024) or 5 minutes (VO(2), p = .0001, VCO(2), p = .0021) of data compared with no exclusions. No significant differences in CVs between the 3- and 5-minute exclusions were found for VO(2) (p = .3224) or VCO(2) (p = .2255). CONCLUSIONS: Clearly, our machines cannot be used interchangeably within a study. An acclimation period improves CVs of VO(2) and VCO(2.) The similarities in CVs led us to adopt a 3-minute acclimation period for measuring REE.  相似文献   
17.
18.
The sensitivity and specificity of maternal serum screening for Down syndrome with different biochemical markers were evaluated. Detection rates with different combinations of maternal serum alpha-fetoprotein (MSAFP), hCG, and unconjugated estriol (uE3) were established by retrieving and analyzing 54 serum specimens from women with confirmed Down syndrome pregnancies, compared with 657 specimens from women with normal outcomes. With a risk cutoff of 1:270 at the second trimester, the detection rate with MSAFP, hCG, and uE3 was two to three times higher than with MSAFP alone. With all three markers, the detection rate for Down syndrome increased from 50 to 77% as maternal age increased, and was 60% in a representative screened population. If uE3 was omitted, the detection rate decreased from 60 to 48%. One thousand women were screened prospectively, either with MSAFP or with all three markers prospectively, either with MSAFP or with all three markers and 4.1% with MSAFP. With the three markers, the positive predictive value for Down syndrome was 2.2% overall and as high as 5.9% in older women. Therefore, the addition of hCG and uE3 to the maternal serum screen increases the positive predictive value by 50-300%, depending on maternal age. These results confirm the efficacy of screening for Down syndrome using maternal age and three serum markers.  相似文献   
19.
Further experience with division of the left renal vein   总被引:2,自引:0,他引:2  
The left renal vein (LRV) has numerous tributaries including, but not limited to, the inferior phrenic, suprarenal, and gonadal veins. The resultant potential for collateral LRV outflow through these tributaries in instances of LRV division is obvious. One of us has previously reported 10 such cases of LRV division (close to its confluence with the inferior vena cava and without reanastomosis) for the purpose of facilitating proximal abdominal aortic exposure for reconstructive procedures. One of the 10 patients had moderate renal insufficiency at follow-up. We present herein an additional 19 patients who underwent LRV division predominantly for aneurysmal disease of the abdominal aorta. Sixteen patients were available for follow-up. Three patients died in the intraoperative and early postoperative periods. Multivariate analysis of variance of preoperative, postoperative, and follow-up laboratory data--serum creatinine and BUN--showed no significant change in renal function as assessed.  相似文献   
20.
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