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   70888篇
  免费   6136篇
  国内免费   2244篇
耳鼻咽喉   560篇
儿科学   1063篇
妇产科学   1173篇
基础医学   7506篇
口腔科学   4545篇
临床医学   15350篇
内科学   6755篇
皮肤病学   860篇
神经病学   4945篇
特种医学   2744篇
外国民族医学   13篇
外科学   11485篇
综合类   7808篇
现状与发展   10篇
一般理论   4篇
预防医学   2307篇
眼科学   652篇
药学   5237篇
  66篇
中国医学   3169篇
肿瘤学   3016篇
  2024年   71篇
  2023年   1429篇
  2022年   1591篇
  2021年   2829篇
  2020年   3137篇
  2019年   3053篇
  2018年   2962篇
  2017年   2842篇
  2016年   2706篇
  2015年   2677篇
  2014年   5003篇
  2013年   6502篇
  2012年   3863篇
  2011年   4384篇
  2010年   3450篇
  2009年   3362篇
  2008年   3650篇
  2007年   3422篇
  2006年   3063篇
  2005年   2678篇
  2004年   2306篇
  2003年   1968篇
  2002年   1541篇
  2001年   1401篇
  2000年   1049篇
  1999年   989篇
  1998年   721篇
  1997年   671篇
  1996年   556篇
  1995年   578篇
  1994年   524篇
  1993年   413篇
  1992年   435篇
  1991年   377篇
  1990年   289篇
  1989年   283篇
  1988年   268篇
  1987年   254篇
  1986年   226篇
  1985年   278篇
  1984年   215篇
  1983年   164篇
  1982年   199篇
  1981年   195篇
  1980年   162篇
  1979年   114篇
  1978年   89篇
  1977年   68篇
  1976年   92篇
  1975年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
IntroductionOur aim was to describe practices in multimodal pain management at US children's hospitals and evaluate the association between non-opioid pain management strategies and pediatric patient-reported outcomes (PROs).MethodsData were collected as part of the 18-hospital ENhanced Recovery In CHildren Undergoing Surgery (ENRICH-US) clinical trial. Non-opioid pain management strategies included use of preoperative and postoperative non-opioid analgesics, regional anesthetic blocks, and a biobehavioral intervention. PROs included perioperative nervousness, pain-related functional disability, health-related quality of life (HRQoL). Associations were analyzed using multinomial logistic regression models.ResultsAmong 186 patients, 62 (33%) received preoperative analgesics, 186 (100%) postoperative analgesics, 81 (44%) regional anesthetic block, and 135 (73%) used a biobehavioral intervention. Patients were less likely to report worsened as compared to stable nervousness following regional anesthetic block (relative risk ratio [RRR]:0.31, 95% confidence interval [CI]:0.11–0.85), use of a biobehavioral technique (RRR:0.26, 95% CI:0.10–0.70), and both in combination (RRR:0.08, 95% CI:0.02–0.34). There were no associations of non-opioid pain control modalities with pain-related functional disability or HRQoL.ConclusionUse of postoperative non-opioid analgesics have been largely adopted, while preoperative non-opioid analgesics and regional anesthetic blocks are used less frequently. Regional anesthetic blocks and biobehavioral interventions may mitigate postoperative nervousness in children.Level of evidenceIII.  相似文献   
2.
Although methadone is effective in the management of acute pain, the complexity of its absorption-distribution-metabolism-excretion profile limits its use as an opioid of choice for perioperative analgesia. Because deuteration is known to improve the pharmacokinetic, pharmacodynamic and toxicological properties of some drugs, here we characterized the single dose pharmacokinetic properties and post-operative analgesic efficacy of d9-methadone.The pharmacokinetic profiles of d9-methadone and methadone administered intravenously to CD-1 male mice revealed that deuteration leads to a 5.7- and 4.4-fold increase in the area under the time-concentration curve and maximum concentration in plasma, respectively, as well as reduction in clearance (0.9 ± 0.3 L/h/kg vs 4.7 ± 0.8 L/h/kg). The lower brain-to-plasma ratio of d9-methadone compared to that of methadone (0.35 ± 0.12 vs 2.05 ± 0.62) suggested that deuteration decreases the transfer of the drug across the blood-brain barrier. The estimated LD50 value for a single intravenous dose of d9-methadone was 2.1-fold higher than that for methadone. Moreover, d9-methadone outperformed methadone in the efficacy against postoperative pain by primarily activating peripheral opioid receptors. Collectively, these data suggest that the replacement of three hydrogen atoms in three methyl groups of methadone altered its pharmacokinetic properties, improved safety, and enhanced its analgesic efficacy.  相似文献   
3.
BackgroundFindings on the usefulness of massage therapy (MT) in postoperative pain management are often inconsistent among studies.ObjectivesThis study’s aim is to conduct a meta-analysis of randomized controlled trials (RCT) to clarify the effects of massage therapy in the treatment of postoperative pain.MethodsThree databases (PubMed, Embase, and Cochrane Central Register of Controlled Trials) were searched for RCTs published from database inception through January 26, 2021. The primary outcome was pain relief. The quality of RCTs was appraised with the Cochrane Collaboration risk of bias tool. The random-effect model was used to calculate the effect sizes and standardized mean difference (SMD) with 95 % confidential intervals (CIs) as a summary effect. The heterogeneity test was conducted through I2. Subgroup and sensitivity analyses were used to explore the source of heterogeneity. Possible publication bias was assessed using visual inspection of funnel plot asymmetry.ResultsThe analysis included 33 RCTs and showed that MT is effective in reducing postoperative pain (SMD, −1.32; 95 % CI, −2.01 to −0.63; p = 0.0002; I2 = 98.67 %). A similar significant effect was found for both short (immediate assessment) and long terms (assessment performed 4–6 weeks after the MT). Remarkably, we found neither the duration per session nor the dose had an impact on the effect of MT and there seemed to be no difference in the effects of different MT types. In addition, MT seemed to be more effective for adults. Furthermore, MT had better analgesic effects on cesarean section and heart surgery than orthopedic surgery.LimitationsPublication bias is possible due to the inclusion of studies in English only. Additionally, the included studies were extremely heterogeneous. Double-blind research on MT is difficult to implement, and none of the included studies is double-blind. There was some heterogeneity and publication bias in the included studies. In addition, there is no uniform evaluation standard for the operation level of massage practitioners, which may lead to research implementation bias.ConclusionsMT is effective in reducing postoperative pain in both short and long terms.  相似文献   
4.
目的:观察评判性护理干预对乳腺癌手术后患者疼痛和睡眠质量的影响。方法:选取2019年1月至2020年5月蚌埠医学院第一附属医院肿瘤内科收治的乳腺癌手术患者126例作为研究对象,按照随机数字表法分为观察组和对照组,每组63例。对照组给予常规护理干预,观察组给予评判性护理干预。采用抑郁自评量表(Self-rating Depression Scale,SDS)、焦虑自评量表(Self-rating Anxiety Scale,SAS)比较2组患者干预前后抑郁、焦虑状态改善情况,采用匹兹堡睡眠指数量表(Pittsburgh Sleep Quality Index,PSQI)比较2组患者睡眠质量变化,同时观察2组患者并发症发生率、中度、重度疼痛患者所占比例。结果:干预后,观察组SAS评分、SDS评分显著低于对照组,观察组PSQI评分显著低于对照组,患者中度、重度疼痛比例降低,并发症发生率降低,观察组的干预效果优于对照组,2组比较差异有统计学意义(P<0.05)。结论:对乳腺癌患者手术后采用评判性护理,可有效缓解患者手术后疼痛程度,改善患者睡眠质量,降低患者焦虑及抑郁情绪,降低并发症发生风险,值得推广使用。  相似文献   
5.
ObjectiveTo analyze the effects of electrolysis, through a medium frequency current, associated to aerobic physical activity in the body composition of young women.MethodsThe study was composed of 34 sedentary women (24.35 ± 4.43 years, 71.30 ± 7.08 kg, 1.61 ± 0.06 m, 27.31 ± 1.67 kg/m2) which were evaluated for their anthropometric measures and body composition. The volunteers were randomly assigned to two group: Electrolyphysis plus Aerobic Exercise (gEEA): 17 volunteers were submitted to the application, for 60 min , of the Aussie current, followed by aerobic physical activity (77% of HRmax) on the trampoline for 40 min, through video-lessons of Jump; and Aerobic Exercise group (gEA): 17 volunteers performed only physical activity following the same parameters mentioned above. Each group performed its protocols twice weekly, for 5 weeks, totaling 10 sessions. For the data analysis, measures repeated ANOVA was performed to compare the means of the variables analyzed before and after the treatment protocols using the SPSS - 21.0 software, adopting a p ≤ 0.05.ResultsAlthough gEEA decreased suprailiac skinfold (p = 0.04), abdominal skinfold (p = 0.03) and circumference at umbilical scar (p = 0.02) in an intragroup analysis, these means differences in anthropometric measures were not important between-groups (p > 0.05). Furthermore, there were no effect of treatment on body composition (p > 0.05).ConclusionTo this studied condition, our results suggested that application of medium frequency electrolysis did not enhance the losses on anthropometric measures and body composition.  相似文献   
6.
目的 观察治伤巴布剂对急性软组织损伤(acute soft tissue injury, ASTI)模型p38丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)、丝/苏氨酸蛋白激酶(AKT)信号通路的影响,探讨治伤巴布剂干预ASTI的可能作用机制。方法 将40只雄性SD大鼠按照随机数字表法分为正常对照组、模型对照组、治伤巴布剂组、p38MAPK信号通路抑制剂组、AKT信号通路抑制剂组,每组8只。除正常对照组外,其余四组均予以左侧后肢小腿ASTI造模。造模成功后,治伤巴布剂组于标记部位立即予治伤巴布剂(修剪成1.5x3cm大小)外敷,并用胶布固定;其余四组均予等剂量赋形剂(修剪成1.5×3 cm大小)外敷处理,胶布固定;持续外敷,共持续24 h。p38MAPK信号通路抑制剂组在造模前30 min予腹腔注射p38MAPK信号通路抑制剂SB203580(400 μg/kg/天)1次;AKT信号通路抑制剂组在造模前30 min予腹腔注射AKT信号通路抑制剂perifosine(20 mg/kg/天)1次。分别于0(造模前)、2h、4h、8h、12h、24h测量受伤小腿肌肉处的周长,并计算肌肉肿胀率(muscle swelling rate,MSR)。24 h药物干预结束后,采用颈椎脱臼法处死大鼠。后将左侧后肢小腿损伤中心部位进行取材,分成三份。一部分用于观察组织病理学形态变化;一部分用于逆转录聚合酶链反应(RT-PCR)检测核因子-κB(nuclear factor kappa-B,NF-κB)p65 mRNA、肿瘤坏死因子-α(TNF-α)mRNA、白细胞介素-1β(IL-1β)mRNA表达水平;剩下部分用酶联免疫吸附试验(ELISA)法检测骨骼肌组织TNF-α、IL-1β含量水平及蛋白质免疫印迹(Western-blot)法测定p38MAPK、AKT、NF-κB p65、核因子抑制蛋白α(inhibitor kappa B alpha, IκBα)表达水平。结果 与正常对照组相比,模型对照组MSR显著增加(P<0.01);病理形态学上,骨骼肌组织可见大面积肌细胞排列紊乱,肌细胞变性坏死,间质内可见红细胞聚集及大量炎症细胞浸润;骨骼肌组织TNF-α、IL-1β含量水平显著升高(P<0.01);磷酸化p38MAPK(p-p38)/总p38MAPK(t-p38),磷酸化-AKT(p-AKT)/总-AKT(t-AKT)明显升高(P<0.01),NF-κB p65及NF-κB p65mRNA表达水平明显升高(P<0.01)。与模型对照组相比,治伤巴布剂组MSR在治疗第8 h、12 h、24 h显著下降(P<0.01),且在治疗第24 h,其MSR较p38MAPK、AKT信号通路抑制剂组下降更明显(P<0.05);病理学评分显著下降(P<0.01),且较p38MAPK、AKT信号通路抑制剂组下降更显著(P<0.05);骨骼肌组织TNF-α、IL-1β含量水平明显下降(P<0.01),且较p38MAPK、AKT信号通路抑制剂组更显著(P<0.05);p-p38/t-p38及p-AKT/t-AKT明显下降(P<0.01),NF-κB p65及NF-κB p65 mRNA表达水平显著下降(P<0.01),且较p38MAPK、AKT信号通路抑制剂组在降低NF-κB p65及NF-κB p65 mRNA相对表达值方面更显著(P<0.01)。结论 治伤巴布剂可能同时对p38MAPK、AKT信号通路产生了一定的抑制作用,引起NF-κB活性下调,NF-κB p65蛋白的表达下调,进而引起骨骼肌组织TNF-α、IL-1β炎性细胞因子含量水平下调,减轻ASTI炎症反应,从而改善ASTI。  相似文献   
7.
BackgroundIntraabdominal and retroperitoneal sarcomas (IaRS) are malignant connective tissue tumors. Surgical resection is often the only curative treatment. The primary objective was to report the mid-term outcomes following contemporary treatment protocols and identify prognostic factors.MethodsA retrospective review of consecutive patients (n = 107) with IaRS treated at single center from 2013 until 2018 was conducted. Histological diagnosis, tumor grade, perioperative complications, mortality, and long-time survival were registered and retrieved from patient records. Primary and recurrent tumors were analyzed separately.ResultsA total of 107 patients were identified. Median follow-up time was 3.5 years. Thirty-day mortality was 3.4% and 90-day mortality was 5.6% for all tumors. The major complication rate was 18%. The 5-year estimated survival for primary and recurrent tumors was 55.4% and 48.4%, respectively. Multifocal disease was evident in 32% of the patient cohort, and 58% of patients in the recurrent group. Multivariate analysis for survival revealed a hazard ratio (HR) of 3.1 (95% CI 1.68–8.41) for multifocality, HR 2.9 (95% CI 1.28–6.98) for Clavien-Dindo grade, HR 2.3 (95% CI 1.21–4.31) for tumor grades 2 or 3, and HR 1.002 (95% CI 1.001–1.004) for surgical margins.ConclusionsOur study found overall acceptable morbidity and mortality, and identified prognostic markers for overall survival. Recurrent tumors were not associated with worse survival. Multifocality is associated with a worse overall survival. The prognostic factors identified were; tumor grade, multifocality, intralesional margins and postoperative complications.  相似文献   
8.
目的探讨多元化联合教学模式在超声引导下疼痛介入治疗教学中的应用效果。方法选择2018年1月至2020年12月在北京大学第三医院疼痛科进修的30名医师作为研究对象,将其分为对照组与观察组;对照组采用常规教学模式;观察组采用多元化联合教学模式,比较两组医师技能考核成绩、教学质量评分和满意度评分。结果观察组医师技能考核成绩优良率为93.3%,高于对照组的73.3%(P<0.05);观察组医师对基础理论知识掌握、临床思维能力的提高、学习兴趣的激发、疾病诊治能力的提高4个方面的评分均高于对照组(P<0.01)。结论多元化联合教学模式可促进超声引导下疼痛介入治疗技能的提高,有利于提高学员的综合临床能力。  相似文献   
9.
On the 25 March 2020 the Chief Dental Officer (CDO) published guidance to restrict the provision of routine dental care in England due to the rapid spread of the severe acute respiratory syndrome Coronavirus 2 (COVID-19). We analysed the impact of the pandemic on the number of patients presenting with odontogenic pain and infection to the emergency department (ED) of an urban-based teaching hospital, the Bristol Royal Infirmary (BRI). Furthermore, we investigated the severity of infection at first presentation to the ED. The study period encompassed three phases that represented the stages of pandemic restrictions: phase 1 prior to lockdown measures, with no restrictions to dental practice; phase 2 during the government lockdown, with the severest restrictions on dental practices; and phase 3 following the ease of lockdown measures, with return to limited dental services. Data were collected retrospectively from electronic patient records (EPR) regarding adult patients presenting to the ED with dental pain. The rate of presentations (per week) was calculated for each timepoint and compared. A severity score was assigned to each patient using a grading system based on signs of clinical infection and treatment modality. Patients' presentations were analysed at each phase of the pandemic. There was a 42.8% increase in attendance with oral facial pain and infection to ED from phases 1 to 3. The COVID-19 pandemic resulted in restrictions to routine primary dental care services, which were deemed necessary to reduce the spread of the virus. However, this increased demand on secondary care services, as patients increasingly struggled to access primary dental care to manage dental pain.  相似文献   
10.
Hyperosmotic tear stimulates human corneal nerve endings, activates ocular immune response, and elicits dry-eye symptoms. A soft contact lens (SCL) covers the cornea preventing it from experiencing direct tear evaporation and the resulting blink-periodic salinity increases. For the cornea to experience hyperosmolarity due to tear evaporation, salt must transport across the SCL to the post-lens tear film (PoLTF) bathing the cornea. Consequently, limited salt transport across a SCL potentially protects the ocular surface from hyperosmotic tear. In addition, despite lens-wear discomfort sharing common sensations to dry eye, no correlation is available between measured tear hyperosmolarity and SCL-wear discomfort. Lack of documentation is likely because clinical measurements of tear osmolarity during lens wear do not interrogate the tear osmolarity of the PoLTF that actually overlays the cornea. Rather, tear osmolarity is clinically measured in the tear meniscus. For the first time, we mathematically quantify tear osmolarity in the PoLTF and show that it differs significantly from the clinically measured tear-meniscus osmolarity. We show further that aqueous-deficient dry eye and evaporative dry eye both exacerbate the hyperosmolarity of the PoLTF. Nevertheless, depending on lens salt-transport properties (i.e., diffusivity, partition coefficient, and thickness), a SCL can indeed protect against corneal hyperosmolarity by reducing PoLTF salinity to below that of the ocular surface during no-lens wear. Importantly, PoLTF osmolarity for dry-eye patients can be reduced to that of normal eyes with no-lens wear provided that the lens exhibits a low lens-salt diffusivity. Infrequent blinking increases PoLTF osmolarity consistent with lens-wear discomfort. Judicious design of SCL material salt-transport properties can ameliorate corneal hyperosmolarity. Our results confirm the importance of PoLTF osmolarity during SCL wear and indicate a possible relation between PoLTF osmolarity and contact-lens discomfort.  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