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   3722篇
  免费   176篇
  国内免费   24篇
耳鼻咽喉   77篇
儿科学   69篇
妇产科学   80篇
基础医学   488篇
口腔科学   67篇
临床医学   343篇
内科学   954篇
皮肤病学   24篇
神经病学   640篇
特种医学   118篇
外科学   361篇
综合类   9篇
一般理论   2篇
预防医学   171篇
眼科学   35篇
药学   215篇
中国医学   15篇
肿瘤学   254篇
  2023年   30篇
  2022年   61篇
  2021年   92篇
  2020年   60篇
  2019年   83篇
  2018年   101篇
  2017年   75篇
  2016年   109篇
  2015年   99篇
  2014年   148篇
  2013年   181篇
  2012年   271篇
  2011年   250篇
  2010年   160篇
  2009年   141篇
  2008年   257篇
  2007年   257篇
  2006年   256篇
  2005年   254篇
  2004年   228篇
  2003年   197篇
  2002年   195篇
  2001年   25篇
  2000年   19篇
  1999年   29篇
  1998年   56篇
  1997年   29篇
  1996年   20篇
  1995年   33篇
  1994年   19篇
  1993年   18篇
  1992年   15篇
  1991年   9篇
  1990年   16篇
  1989年   12篇
  1988年   7篇
  1987年   10篇
  1986年   8篇
  1985年   11篇
  1984年   13篇
  1983年   7篇
  1982年   15篇
  1981年   5篇
  1980年   7篇
  1979年   5篇
  1978年   3篇
  1976年   3篇
  1974年   8篇
  1973年   4篇
  1970年   3篇
排序方式: 共有3922条查询结果,搜索用时 0 毫秒
51.
52.
AIM: To compare the site, age and gender of cases of colorectal cancer (CRC) and polyps in a single referral center in Rome, Italy, during two periods.METHODS: CRC data were collected from surgery/pathology registers, and polyp data from colonoscopy reports. Patients who met the criteria for familial adenomatous polyposis, hereditary non-polyposis colorectal cancer syndrome or inflammatory bowel disease were excluded from the study. Overlap of patients between the two groups (cancers and polyps) was carefully avoided. The χ2 statistical test and a regression analysis were performed.RESULTS: Data from a total of 768 patients (352 and 416 patients, respectively, in periods A and B) who underwent surgery for cancer were collected. During the same time periods, a total of 1693 polyps were analyzed from 978 patients with complete colonoscopies (428 polyps from 273 patients during period A and 1265 polyps from 705 patients during period B). A proximal shift in cancer occurred during the latter years for both sexes, but particularly in males. Proximal cancer increased > 3-fold in period B compared to period A in males [odds ratio (OR) 3.31, 95%CI: 2.00-5.47; P < 0.0001). A similar proximal shift was observed for polyps, particularly in males (OR 1.87, 95%CI: 1.23-2.87; P < 0.0038), but also in females (OR 1.62, 95%CI: 0.96-2.73; P < 0.07).CONCLUSION: The prevalence of proximal proliferative colonic lesions seems to have increased over the last decade, particularly in males.  相似文献   
53.
54.
55.
56.
57.
58.
OBJECTIVES: The aim of this study was to assess the potential value of hand-carried ultrasound (HCU) devices in the diagnosis and follow-up of patients with pleural effusion (PE) after cardiac surgery. METHODS: Seventy consecutive patients were evaluated at bedside early after cardiac surgery, in the upright sitting position, using an HCU device on hospital admission and every 3 days until hospital discharge. The posterior chest wall was scanned along the paravertebral, scapular, and posterior axillary lines. For each hemithorax, an effusion index was derived as the sum of the intercostal spaces between the lower and upper limits of the PE along the lines of scanning, divided by 3. A standard chest radiograph was performed in all patients on hospital admission and at hospital discharge, and was qualitatively scored (0, absent; 1, small; 2, large PE). The findings of the HCU device and radiograph were compared using kappa statistics and the Kruskal-Wallis test. RESULTS: A chest ultrasound was feasible in all patients (mean [+/- SD] time, 5 +/- 2 min). Compared with the chest ultrasound, a physical examination showed a sensitivity of 69% and a specificity of 77%. On hospital admission, the HCU device detected a PE in 72 of 140 hemithoraxes. Agreement with the finding of the radiograph was 76% (kappa = 0.52). In 15 hemithoraxes, the HCU device revealed a PE that had not been diagnosed using the radiograph. Conversely, in 18 hemithoraxes a PE that had been diagnosed with a radiograph was not confirmed by the HCU device. The correlation between ultrasound and radiographic scores was statistically significant (p < 0.001). At hospital discharge, a PE was present in 31 of 140 hemithoraxes according to the findings of the HCU device, and in 38 of 140 hemithoraxes according to the findings of the radiograph (agreement, 78%; kappa = 0.44). CONCLUSIONS: In patients early after cardiac surgery, HCU devices allow rapid PE detection and improve the clinical diagnosis. Compared to a radiograph, this method offers the unique advantage of the bedside evaluation of patients without the need for radiation exposure.  相似文献   
59.
60.
Percutaneous revascularization of saphenous vein grafts (SVGs) remains a challenging task. Drug-eluting stents (DESs) have been shown to decrease the incidence of restenosis in de novo native coronary artery lesions. However, their clinical value in SVGs remains to be established. We compared long-term clinical outcomes of percutaneous coronary intervention with DESs and bare metal stents (BMSs) for de novo lesions in SVGs. In a large prospective, multicenter registry, 360 patients underwent stenting of a de novo lesion in SVGs using BMSs (288 patients) or DESs (72 patients). Incidence of major adverse cardiac events (MACEs), including all-cause mortality, reinfarction, and target vessel revascularization, was recorded at a 12-month follow-up. Compared with the DES group, patients receiving BMSs were more likely to be men, to have chronic renal insufficiency or higher Charlson scores, but less likely to have undergone previous percutaneous coronary intervention. Incidence of MACEs at 12-month follow-up was similar in the 2 groups (17.8% in DES group vs 20.3% in BMS group, respectively, p = 0.460). Cox regression analysis identified age, chronic renal failure, cardiogenic shock at presentation, and ostial location of stenosis as independent predictors of long-term MACEs. In conclusion, our data suggest that rates of 12-month MACEs associated with the use of DESs and BMSs are similar in patients undergoing treatment of de novo lesions in SVGs.  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