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   90692篇
  免费   7081篇
  国内免费   2478篇
耳鼻咽喉   240篇
儿科学   3504篇
妇产科学   1133篇
基础医学   8869篇
口腔科学   625篇
临床医学   12068篇
内科学   14605篇
皮肤病学   560篇
神经病学   4270篇
特种医学   3024篇
外国民族医学   5篇
外科学   6247篇
综合类   16347篇
现状与发展   8篇
预防医学   6585篇
眼科学   986篇
药学   7834篇
  86篇
中国医学   11440篇
肿瘤学   1815篇
  2024年   295篇
  2023年   1341篇
  2022年   2452篇
  2021年   3771篇
  2020年   3532篇
  2019年   2773篇
  2018年   2650篇
  2017年   3026篇
  2016年   3063篇
  2015年   2997篇
  2014年   5628篇
  2013年   5860篇
  2012年   4950篇
  2011年   5263篇
  2010年   4150篇
  2009年   3768篇
  2008年   3775篇
  2007年   3963篇
  2006年   3600篇
  2005年   3241篇
  2004年   2916篇
  2003年   2671篇
  2002年   2317篇
  2001年   2225篇
  2000年   1855篇
  1999年   1625篇
  1998年   1490篇
  1997年   1546篇
  1996年   1256篇
  1995年   1275篇
  1994年   1173篇
  1993年   929篇
  1992年   910篇
  1991年   831篇
  1990年   675篇
  1989年   643篇
  1988年   636篇
  1987年   514篇
  1986年   493篇
  1985年   707篇
  1984年   572篇
  1983年   363篇
  1982年   523篇
  1981年   397篇
  1980年   344篇
  1979年   279篇
  1978年   210篇
  1977年   195篇
  1976年   190篇
  1975年   96篇
排序方式: 共有10000条查询结果,搜索用时 30 毫秒
1.
2.
《Cancer cell》2022,40(3):318-334.e9
  1. Download : Download high-res image (268KB)
  2. Download : Download full-size image
  相似文献   
3.
BackgroundThe goal of this study was to characterize contemporary performance benchmarks and risk factors associated with negative appendectomy (NA) in children with suspected appendicitis.MethodsA multicenter retrospective cohort analysis of children undergoing appendectomy for suspected appendicitis was performed using data from the 2016–2021 NSQIP-Pediatric Appendectomy Targeted Public Use Files. Multivariable regression was used to evaluate the influence of year, age, sex, and WBC count on NA rate, and to generate rate estimates for NA based on different combinations of demographic characteristics and WBC profiles.Results100,322 patients were included from 140 hospitals. The overall NA rate was 2.4%, and rates decreased significantly during the study period (2016: 3.1% vs. 2021: 2.3%, p < 0.001). In adjusted analyses, the highest risk for NA was associated with a normal WBC (<9000/mm3; OR 5.31 [95% CI: 4.87–5.80]), followed by female sex (OR 1.55 [95% CI: 1.42–1.68]) and age <5 years (OR 1.64 [95% CI 1.39, 1.94]). Model-estimated risk for NA varied significantly across demographic and WBC strata, with a 14.4-fold range in rates between subgroups with the lowest and highest predicted risk (males 13–17 years with elevated WBC [1.1%] vs. females 3–4 years with normal WBC [15.8%]).ConclusionsContemporary NA rates have decreased over time, however NA risk remains high in children without a leukocytosis, particularly for girls and children <5 years of age. These data provide contemporary performance benchmarks for NA in children with suspected appendicitis and identify high-risk populations where further efforts to mitigate NA risk should be targeted.Level of EvidenceIII.  相似文献   
4.
5.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.  相似文献   
6.
目的 运用核磁共振弥散张量成像技术(DTI),从皮质脊髓束损伤程度评价的角度,探讨肾虚髓亏证与急性缺血性脑卒中运动功能缺损程度相关性,丰富中风病病机及证候诊断,拓宽缺血性脑卒中的中医药防治思路,为急性缺血性脑卒中肾虚髓亏证患者运动功能损伤程度提供临床依据,强调肾虚髓亏证在急性缺血性脑卒中运动功能损伤中的重要意义。方法 纳入符合诊断标准的90例病例,根据证候分别归入肾虚髓亏组和非肾虚髓亏组,每组各45例。每组患者均给予常规西药治疗。对两组患者入院后行弥散张量成像检测,同时分别于治疗前及治疗后14天,记录两组患者NIHSS评分、改良Barthel指数量表及简化Fugl-Meyer运动功能评分量表评分,比较两组病例发病时的轻重程度及治疗前后两组病例组间的恢复差异。结果 研究显示,治疗前肾虚髓亏组在NIHSS评分方面高于非肾虚髓亏组(P<0.05);治疗前肾虚髓亏组在改良Barthel指数量表及简化Fugl-Meyer运动功能评分方面低于非肾虚髓亏组(P<0.05)。治疗前后NIHSS评分、改良Barthel指数评分及简化Fugl-Meyer运动功能评分改善情况,非肾虚髓亏组要优于肾虚髓亏组(P<0.05)。治疗前两组患者在健侧内囊后肢及大脑脚外侧处FA值及ADC值无明显差异;肾虚髓亏组在患侧内囊后肢及大脑脚外侧处FA值及ADC值均低于非肾虚髓亏组(P<0.05)。相关性分析得出,两组患者患侧内囊后肢FA值与患者治疗前NIHSS评分呈负相关;两组患者患侧内囊后肢FA值与患者改良Barthel指数评分及简化Fugl-Meyer运动功能评分呈正相关;肾虚髓亏组患者患侧内囊后肢FA值与肾虚髓亏证中医证候评分呈负相关。结论 肾虚髓亏是急性缺血性脑卒中运动功能障碍的重要病机。研究结果显示,两组皮质脊髓束损伤程度与神经功能及运动功能损伤存在相关性,且肾虚髓亏组在皮质脊髓束的损伤程度方面与其中医证候评分呈负相关。  相似文献   
7.
8.
PurposeTo evaluate the midterm outcomes of percutaneous transluminal renal angioplasty (PTRA) for pediatric renovascular hypertension (RVH).Materials and MethodsThe clinical data of patients who underwent PTRA for RVH in the authors’ hospital from 2012 to 2019 were retrospectively analyzed. Postprocedural blood pressure, glomerular filtration rate (GFR) of the affected kidney, restenosis, and complications were closely monitored.ResultsPTRA was performed in a total of 30 children (20 boys and 10 girls), with a mean age of 7.3 years ± 0.7 (range, 40 days to 13.9 years) and a mean weight of 25.0 kg ± 2.3 (range, 3.4–53 kg). The median follow-up period was 26.5 months (range, 1 month to 7.5 years). Technical success was achieved in 26 (86.7%) of the 30 patients. Restenosis developed in 3 patients (10.0%). Only 1 patient underwent stent implantation, and the stent fractured 8 months later, requiring further intervention. There were no other complications. In terms of clinical benefit of blood pressure control after the initial PTRA procedure, 15 patients (50%) were cured and 7 patients (23.3%) showed improvement. There was no significant difference in the etiology, lesion location, and lesion length between patients with clinical benefit and failure (P = .06, P = .202, and P = .06, respectively). GFR of the affected kidney was significantly improved from 19.9 mL/min ± 11.2 to 38.1 mL/min ± 11.9 at the 6-month follow-up after PTRA (P < .001).ConclusionsThe overall results of PTRA for pediatric RVH caused by different etiologies are promising. PTRA not only provided a clinical benefit of blood pressure control in 73.3% of the patients but also significantly improved the function of the affected kidney.  相似文献   
9.
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