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   9920篇
  免费   1817篇
  国内免费   70篇
耳鼻咽喉   267篇
儿科学   3159篇
妇产科学   29篇
基础医学   519篇
口腔科学   216篇
临床医学   1295篇
内科学   1135篇
皮肤病学   208篇
神经病学   384篇
特种医学   159篇
外国民族医学   1篇
外科学   1539篇
综合类   440篇
一般理论   3篇
预防医学   414篇
眼科学   695篇
药学   564篇
  31篇
中国医学   203篇
肿瘤学   546篇
  2024年   48篇
  2023年   505篇
  2022年   187篇
  2021年   549篇
  2020年   809篇
  2019年   807篇
  2018年   736篇
  2017年   697篇
  2016年   634篇
  2015年   550篇
  2014年   769篇
  2013年   931篇
  2012年   564篇
  2011年   486篇
  2010年   428篇
  2009年   436篇
  2008年   403篇
  2007年   399篇
  2006年   304篇
  2005年   288篇
  2004年   151篇
  2003年   155篇
  2002年   108篇
  2001年   105篇
  2000年   78篇
  1999年   62篇
  1998年   65篇
  1997年   75篇
  1996年   40篇
  1995年   51篇
  1994年   46篇
  1993年   36篇
  1992年   56篇
  1991年   43篇
  1990年   26篇
  1989年   28篇
  1988年   20篇
  1987年   14篇
  1986年   11篇
  1985年   23篇
  1984年   26篇
  1983年   14篇
  1982年   11篇
  1981年   9篇
  1980年   11篇
  1979年   4篇
  1978年   4篇
  1977年   2篇
  1975年   2篇
  1973年   1篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Abstract –  The aims of this study were to analyze the histomorphology of developing permanent teeth whose primary teeth had suffered traumatic intrusion, as well as to compare the influence of immediate extraction of the intruded tooth to passive re-eruption. Nine dogs from 45 to 50 days old were submitted to the intrusion of the maxillary central and lateral primary incisors using a force applicator adapted to the teeth incisal cuspids. The right side intruded teeth were kept in their sockets and the ones on the left side were extracted 30 min later. After a postoperatory periods of 30 and 60 days, four (group 1) and five (group 2) dogs, respectively, were killed by perfusion. The histological evaluations showed that, in group 1, alterations had occurred in the odontoblastic layer and deposition of the enamel matrix had taken place in some specimens while in group 2, a portion of non-mineralized matrix was observed. We concluded that the morphological changes were because of the immediate trauma of intrusion. No differences were found between the groups where the primary tooth was immediately extracted or left to passively re-erupt.  相似文献   
62.
63.
Modified ultrafiltration after cardiopulmonary bypass in children has been shown to be associated with an increase in arterial blood pressure. As part of a series of studies to investigate the possible causes of this blood pressure elevation, the hypothesis that if filtration was removing a significant amount of fentanyl, then the increase in blood pressure might be due to pain was proposed. Ten children, aged between 0.5 and 9.3 years (median 3.8 years), weighing 5.9 to 25..5 kg (median 15.7 kg), underwent corrective cardiac surgery (incorporating modified ultrafiltration). A standard anesthetic protocol was followed, with up to 78 μg/kg of fentanyl given prebypass for analgesia. After completion of cardiopulmonary bypass, modified ultrafiltration was commenced at 100 mL/min until a hematocrit of 35% was reached. Samples were taken of arterial blood (prefiltration, 3, 10, and 20 minutes postfiltration), the venous reservoir blood (prefiltration) and the filtrate (5 and 10 minutes into filtration). Hemodynamic data were recorded both prefiltration and postfiltration. The hemodynamic data showed the expected rise in both systemic arterial pressure and cardiac index after ultrafiltration. The plasma fentanyl concentrations did not significantly change after ultrafiltration: 1.59 to 12.39 ng/mL (median 6.27 ng/mL) prefiltration and 2.05 to 15.59 ng/mL (6.29 ng/mL) at 3 minutes, 2.22 to 12.64 ng/mL (6.87 ng/mL) at 10 minutes, and 1.83 to 11.52 ng/mL (5.85 ng/mL) at 20 minutes postfiltration. The concentration of fentanyl in the venous reservoir, 2.06 to 11.64 ng/mL (7.04 ng/mL), was not significantly different from the plasma levels. The level of fentanyl in the filtrate was significantly less than the plasma levels, 0.243 to 1.87 ng/mL (0.894 ng/mL) at 5 minutes and 0.385 to 1.688 ng / mL (0.952 ng / mL) at 10 minutes into filtration; (P < 0.02 by the Wilcoxon signed-rank method). The data show that the plasma fentanyl concentration was not significantly reduced by modified ultrafiltration. The fentanyl levels found prefiltration were maintained postfiltration, and the observed changes in systemic arterial pressure were not due to an acute fall in the plasma concentration of analgesic drug.  相似文献   
64.
We report the case of a 36-year-old woman admitted for cryptogenic stroke, in whom the Patent Foramen Ovale (PFO) diameter measurement, with a purpose built sizing balloon, performed before the closure procedure, was complicated with the rupture of the inter-atrial septum generating an Atrial Septal Defect (ASD) with a significant left-to-right shunt. This kind of complication may not be easy to handle, changing the initial procedural strategy from PFO to ASD closure technique requiring specific material and operator's technical skill.  相似文献   
65.
潘丽  黄福文 《广西医学》2004,26(11):1600-1603
目的 采用多普勒超声心动图评价儿童急性肾炎 (AGN)早期左室舒张功能 (LVDF)损害的严重程度及疗效观察。方法 将 76例急性肾炎患儿按病情程度分为轻度、重度两组与 5 4例健康对照组进行对照。应用HP - 10 0 0型超声诊断仪 ,分别于治疗前和治疗后 2周测定二尖瓣舒张早期峰值流速 (EV)、二尖瓣舒张晚期峰值流速 (AV)、EV AV比值、舒张早期充盈分数(EI)、舒张晚期充盈分数 (AI)、EI AI比值、E峰加速时间 (AT)、E峰减速时间 (DT)、DT AT比值、肺静脉收缩期最大前向血流速度(S)、舒张期最大前向血流速度 (D)、D S比值、左房内径 (LA)、主动脉内径 (AO)、LA AO比值等 11项指标。结果 EV AV、EI AI、LA AO、D S是判断LVDF损害的重要指标 ;LVDF损害与病情严重程度有关 ,其中 ,EV、EV AV、EI、EI AI、AT、D S随病情加重而降低 ,AV、AI、DT、DT AT、LA AO随病情加重而增高 ;EI、AI、AT、DT、DT AT是评价其疗效的重要指标 ;治疗后 ,LVDF恢复时间晚于临床症状恢复时间。结论 上述指标可动态检测LVDF ,对指导临床诊治具有重要意义。同时该检测方法操作简便易行、重复性强、无痛苦 ,结果较为精确。  相似文献   
66.
To describe the evolution, risk factors and impact of nonimmune histological injury after pediatric kidney transplantation, we analyzed 245 renal allograft protocol biopsies taken regularly from the time of transplantation to 2 years thereafter in 81 consecutive rejection-free pediatric recipients of an adult-sized kidney. Isometric tubular vacuolization was present early after transplantation was not progressive, and was associated with higher tacrolimus pre-dose trough levels. Chronic tubulo-interstitial damage and tubular microcalcifications were already noted at 3 months, were progressive and had a greater association with small recipient size, male donor gender, higher donor age and female recipient gender, but not with tacrolimus exposure. Renal function assessment showed that older recipients had a significant increase in absolute glomerular filtration rate with time after transplantation, which differed from small recipients who showed no increase. It is concluded that progressive, functionally relevant, nonimmune injury is detected early after adult-sized kidney transplantation in pediatric recipients. Renal graft ischemia associated with the donor-recipient size discrepancy appears to be a greater risk factor for this chronic histological injury, suggesting that the exploration of additional therapeutic approaches to increase allograft perfusion could further extend the graft survival benefit of adult-sized kidneys transplanted into small children.  相似文献   
67.
Obsessive-compulsive disorder (OCD) is a distressing and functionally impairing disorder that can emerge as early as age 4. Cognitive behavior therapy (CBT) for OCD in youth shows great promise for amelioration of symptoms and associated functional impairment. However, the empirical evidence base for the efficacy of CBT in youth has some significant limitations, particularly as related to treating the very young child with OCD. This report includes a quantitative review of existing child CBT studies to evaluate evidence for the efficacy of CBT for OCD. It identifies gaps in the literature that, when addressed, would enhance the understanding of effective treatment in pediatric OCD. Finally, it presents a proposed research agenda for addressing the unique concerns of the young child with OCD.  相似文献   
68.
Timely access to a living donor (LD) reduced pretransplant mortality in pediatric liver transplantation (LT). We hypothesized that this strategy may provide better posttransplant outcome. Between July 1993 and April 2002, 235 children received a primary LT from a LD (n = 100) or a deceased donor (DD) (n = 135). Demographic, surgical and immunological variables were compared, and respective impact on posttransplant complications was studied using a multivariate analysis. Five-year patient survival rates were 92% and 85% for groups LD and DD, respectively (p = 0.181), the corresponding graft survival rates being 89% and 77% (p = 0.033). At multivariate analysis: (1) type of donor (DD) was correlated with higher rate of artery thrombosis (p < 0.012); (2) biliary complication rate at 5 years was 29% and 23% for groups LD and DD, respectively (p = 0.451); (3) lower acute rejection incidence could be correlated with type of donor (DD) (p = 0.001), and immunosuppressive therapy (tacrolimus) (p < 0.001). We conclude that (1) according to the multivariate analysis, LT with LD provided similar patient and graft outcome, when compared to DD; (2) a higher rate of artery thrombosis and a lower rate of rejection were observed in group DD; (3) this study confirms the efficacy of tacrolimus for immunoprophylaxis, whatever the type of organ donor is.  相似文献   
69.
Oral valganciclovir is effective prophylaxis for cytomegalovirus (CMV) disease in adults receiving solid organ transplantation (SOT). However, data in pediatrics are limited. This study evaluated the pharmacokinetics and safety of valganciclovir oral solution or tablets in 63 pediatric SOT recipients at risk of CMV disease, including 17 recipients ≤2 years old. Patients received up to 100 days' valganciclovir prophylaxis; dosage was calculated using the algorithm: dose (mg) = 7 × body surface area × creatinine clearance (Schwartz method; CrCLS). Ganciclovir pharmacokinetics were described using a population pharmacokinetic approach. Safety endpoints were measured up to week 26. Mean estimated ganciclovir exposures showed no clear relationship to either body size or renal function, indicating that the dosing algorithm adequately accounted for both these variables. Mean ganciclovir exposures, across age groups and organ recipient groups were: kidney 51.8 ± 11.9 μg * h/mL; liver 61.7 ± 29.5 μg * h/mL; heart 58.0 ± 21.8 μg * h/mL. Treatment was well tolerated, with a safety profile similar to that in adults. Seven serious treatment-related adverse events (AEs) occurred in five patients. Two patients had CMV viremia during treatment but none experienced CMV disease. In conclusion, a valganciclovir-dosing algorithm that adjusted for body surface area and renal function provides ganciclovir exposures similar to those established as safe and effective in adults  相似文献   
70.
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