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   2100篇
  免费   272篇
  国内免费   22篇
耳鼻咽喉   28篇
儿科学   65篇
妇产科学   65篇
基础医学   110篇
口腔科学   75篇
临床医学   309篇
内科学   487篇
皮肤病学   38篇
神经病学   83篇
特种医学   301篇
外科学   224篇
综合类   22篇
预防医学   308篇
眼科学   14篇
药学   38篇
肿瘤学   227篇
  2023年   54篇
  2022年   18篇
  2021年   19篇
  2020年   48篇
  2019年   31篇
  2018年   65篇
  2017年   36篇
  2016年   48篇
  2015年   58篇
  2014年   116篇
  2013年   144篇
  2012年   70篇
  2011年   71篇
  2010年   77篇
  2009年   100篇
  2008年   71篇
  2007年   103篇
  2006年   75篇
  2005年   66篇
  2004年   59篇
  2003年   28篇
  2002年   29篇
  2001年   37篇
  2000年   40篇
  1999年   32篇
  1998年   71篇
  1997年   94篇
  1996年   81篇
  1995年   60篇
  1994年   65篇
  1993年   55篇
  1992年   20篇
  1991年   17篇
  1990年   39篇
  1989年   44篇
  1988年   32篇
  1987年   36篇
  1986年   33篇
  1985年   34篇
  1984年   17篇
  1983年   13篇
  1982年   24篇
  1981年   31篇
  1980年   18篇
  1979年   7篇
  1978年   8篇
  1977年   17篇
  1976年   19篇
  1975年   13篇
  1969年   7篇
排序方式: 共有2394条查询结果,搜索用时 15 毫秒
51.
Pathological gambling (PG) is a signi.cant public health concern associated with high rates of psychiatric comorbidity and mortality. Although research into the biology of PG is still in an early stage, recent advances in our understanding of motivation, reward, and addiction have provided substantial insight into the possible pathophysiology of this disorder. In addition, over the past 5 years, extraordinary progress has been made in the area of clinical research examining treatments for PG. Although PG is a disabling disorder that continues to represent a clinical challenge for the healthcare professional, our current knowledge of pharmacotherapy and psychosocial interventions offers potentially effective treatment options.  相似文献   
52.
Introduction Postoperative paraplegia remains a dreaded complication of repair of traumatic rupture of the aortic isthmus. Claims have been made that left atrial-femoral bypass provides better spinal cord protection. To test the hypothesis that left atrial-femoral bypass is better than femoral vein-to-femoral artery bypass in regard to postoperative paraplegia, we concurrently compared the two techniques. Methods We compared the occurrence of paraplegia in 18 patients whose ruptures were repaired utilizing left atrial-femoral bypass with 10,000 units of systemic heparin (group A) and 72 patients with femoral-femoral bypass with heparin 300 units/kg and an oxygenator (group B) operated on between January 1995 and July 2004. Results The mortality rate was 5.6% (5/90), with no statistical difference between the two groups. Postoperative paraplegia was present in three (16.7%) group A patients and five group B (6.9%) patients. However, the specific etiology of the neurologic defect was not clear, as one patient’s paraplegia was transient following a period of cardiac arrest, and four others had had neurologic injuries prior to the aortic repair. Median aortic cross-clamp times were shorter in group A (34 minutes vs. 49 minutes). No patient required reexploration for bleeding, and no patient developed a graft infection. Conclusions Paraplegia rates were higher in the left atrial-femoral group, but the difference was not statistically significant. This occurred despite the decreased cross-clamp times in this group. In patients undergoing repair of traumatic rupture of the aortic isthmus, left atrial-femoral bypass does not provide better spinal cord protection than femoral-femoral bypass.  相似文献   
53.
PURPOSE: To test the hypothesis that TS3'UTR polymorphisms predict outcomes in 146 Caucasian patients with esophageal adenocarcinoma treated with preoperative 5-fluorouracil-based chemoradiation. METHODS AND MATERIALS: DNA was extracted from hematoxylin-and-eosin stained histologic slides of normal esophageal or gastric mucosa sections from paraffin blocks of esophagectomy specimens. Genotypes of the TS3'UTR polymorphism were determined by polymerase chain reaction for a 6-bp insertion. The genotype groups (0bp/0bp, 6bp/0bp, and 6bp/6bp) were compared for clinical features and overall survival, recurrence-free-survival, locoregional control (LRC), and distant metastasis control. Multivariable Cox regression analyses were performed to find independent predictors for the stated outcomes. RESULTS: There was a trend of association between 6bp/6bp genotype and a decreased risk of local regional recurrence (hazards ratio = 0.211, 95% confidence interval = 0.041-1.095, p = 0.06) compared with other genotypes. There was a trend that patients with 6bp/6bp genotype had a higher 3-year probability of LRC compared with patients with the other two genotypes combined (p = 0.07); however, the difference was not statistically significant. CONCLUSIONS: The null hypotheses were not rejected in this study, probably owing to small sample size or the single gene examined. Prospective studies with adequate statistical power analyzing a family of genes involved in the 5-fluorouracil metabolism are needed to assess genetic determinants of treatment-related outcomes in esophageal adenocarcinoma.  相似文献   
54.
55.
BACKGROUND: Tumor viability assessed by pathologic analysis of resected specimens in patients with preoperatively treated esophageal adenocarcinoma (EAC) is a prognostic indicator. The feasibility of induction chemotherapy followed by concurrent chemoradiotherapy (CCRT) and surgery for patients with locoregionally advanced EAC has been demonstrated. In this study, the authors evaluated the efficacy of CCRT compared with traditional concurrent chemoradiotherapy (CRT). METHODS: The authors retrospectively reviewed 247 consecutive patients with EAC who presented for planned surgery after treatment with either CCRT or CRT from January 1997 through August 2003. Patient demographics, comorbidities, and tumor characteristics were analyzed. Pathologic tumor response, overall survival, and disease-free survival were assessed according to treatment. RESULTS: One hundred seventeen patients received CCRT, and 130 patients received CRT before planned surgical resection. CCRT resulted in a 64% tumor response rate compared with a 51% tumor response rate in the CRT group (odds ratio, 1.73; P = .035). In the CCRT group, the median overall survival was 55 months, and the 3-year overall survival rate was 59%; in the CRT group, the median overall survival was 25 months, and the 3-year overall survival rate was 41% (hazard ratio [HR], 0.69; P = .041). In the CCRT group, the median disease-free survival was 43 months, and the 3-year disease-free survival rate was 54%; in the CRT group, the median disease-free survival was 18 months, and the 3-year disease-free survival rate was 36% (HR, 0.72; P = .047). Subset analysis of patients with clinical Stage III/IVA disease showed a median overall survival of 51 months with a 3-year overall survival rate of 58% in the CCRT group and a median overall survival of 20 months with a 3-year overall survival rate of 28% in the CRT group (HR, 0.57; P = .019). CONCLUSIONS: In patients with EAC, CCRT improved tumor response significantly compared with traditional CRT alone. Overall survival and disease-free survival were increased in patients who received CCRT, especially in the subset of patients who had more advanced disease.  相似文献   
56.
57.
58.
SUMMARY The efficacy and safety of the methylprednisolone prodrugs methylprednisolone suleptanate and methylprednisolone sodium succinate were evaluated in a multicentre, randomised, double-blind, double-dummy parallel study of 88 patients hospitalised with acute asthma. Each study drug was administered as a bolus intravenous injection of 40mg methylprednisolone equivalents every 6 hours for 48 hours. Methylprednisolone 32mg was administered orally 6 hours after the last dose. Pulmonary function, medical events, and clinical laboratory values were assessed at predefined intervals before and during the 72-hour study. The primary response measure of pulmonary function was per cent predicted forced expiratory volume in one second (FEV1) at 48 hours. Secondary response measures were peak expiratory flow rate (PEFR) and FEV1/forced vital capacity (FVC) ratio. Although both drugs demonstrated within-group mean changes from baseline (starting at 6 hours) that were statistically significant for each response, there were no statistically significant differences between the two groups. The mean percent predicted FEV1 at 48 hours and mean per cent change from baseline were 64% and 13% (p<0.0001) for the methylprednisolone suleptanate group and 67% and 17% (p<0.0001) for the methylprednisolone sodium succinate group, respectively. The mean PEFR and FEV1/FVC ratio at 48 hours were 5.77 l/s and 73% for the methylprednisolone suleptanate group and 5.78 l/s and 76% for the methylprednisolone sodium succinate group, respectively. There were no clinically or statistically significant between-group differences in any of the safety parameters. In this study, methylprednisolone suleptanate and methylprednisolone sodium succinate have been shown to be therapeutically equivalent in the treatment of patients hospitalized with acute asthma.  相似文献   
59.
The use of the newly dead to teach procedures is widely practiced in training institutions. This model allows a realistic opportunity both to become more familiar with lifesaving maneuvers before they are actually necessary and to maintain proficiency. Whether to notify the next of kin first has been an issue of ethical debate. Some argue a "don't ask, don't tell" policy is justified, while others mandate open consent by family members prior to the practice. Several medical studies have found that patients and families are likely to consent to the procedures but prefer to be asked permission first. Multiple legal cases have addressed the issue of usage of cadavers postmortem without expressed permission. Earlier cases emphasized the concept of "pseudo-property" rights and declared that the next of kin do not have constitutional ownership of the deceased person's body. More recent legal cases are declaring that families do, in fact, possess these rights. In this day and age of increasing recognition of personal autonomy, it is probably prudent to approach the next of kin for permission before performing procedures on the newly deceased.  相似文献   
60.
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