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   89139篇
  免费   6602篇
  国内免费   1832篇
耳鼻咽喉   630篇
儿科学   1745篇
妇产科学   1241篇
基础医学   6408篇
口腔科学   2135篇
临床医学   18246篇
内科学   12957篇
皮肤病学   767篇
神经病学   6872篇
特种医学   2483篇
外国民族医学   9篇
外科学   11683篇
综合类   10404篇
现状与发展   5篇
一般理论   5篇
预防医学   5007篇
眼科学   3693篇
药学   8330篇
  81篇
中国医学   3220篇
肿瘤学   1652篇
  2024年   214篇
  2023年   1738篇
  2022年   2814篇
  2021年   3968篇
  2020年   3794篇
  2019年   3561篇
  2018年   3438篇
  2017年   3273篇
  2016年   3147篇
  2015年   3035篇
  2014年   5995篇
  2013年   7125篇
  2012年   4708篇
  2011年   5255篇
  2010年   4075篇
  2009年   3916篇
  2008年   4283篇
  2007年   4012篇
  2006年   3580篇
  2005年   2938篇
  2004年   2586篇
  2003年   2099篇
  2002年   1827篇
  2001年   1682篇
  2000年   1330篇
  1999年   1258篇
  1998年   1080篇
  1997年   1058篇
  1996年   847篇
  1995年   873篇
  1994年   789篇
  1993年   686篇
  1992年   692篇
  1991年   580篇
  1990年   505篇
  1989年   480篇
  1988年   474篇
  1987年   446篇
  1986年   426篇
  1985年   490篇
  1984年   469篇
  1983年   300篇
  1982年   368篇
  1981年   302篇
  1980年   257篇
  1979年   214篇
  1978年   179篇
  1977年   110篇
  1976年   95篇
  1975年   78篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
This meta-analysis was designed to assess the effectiveness and safety of extracorporeal shock wave therapy (ESWT) for patients with low back pain (LBP). Pubmed, Embase, Cochrane's library, PEDro (Physiotherapy Evidence Database), China National Knowledge Infrastructure (CNKI), and Wanfang Data were searched until December 2019 to identify studies assessing the effectiveness and safety of EPSW for LBP. The prime outcome is pain intensity measured by Visual Analog Scale (VAS) or numeric rating scale (NRS). Other outcomes included functional status, quality of life, psychological outcomes measured by Oswestry Disability Index (ODI), as well as the adverse events. Mean differences (MD) were calculated for continuous outcomes, while odd ratios (OR) were calculated for binary outcomes. Revman 5.3 software was used for statistical analysis. Five randomized controlled trials (RCTs) were finally included in this meta-analysis. The pooled mean difference in post-treatment pain scores was −2.37 (P <0.0001), indicating that post-treatment pain scores was significantly higher by 2.37 in control group than in ESWT group. At a mean follow-up time of 4–6 weeks, the pooled mean difference in ODI scores was −14.10 (P <0.00001), indicating that the pooled mean difference of post-treatment ODI scores was 14.10 higher in control group than in ESWT group. The use of ESWT is effective in alleviating pain and improving the general functional state for patients with LBP. However, more evidence was needed to verify its safety.  相似文献   
2.
3.
ObjectiveTo compare levels of postoperative oxycodone use and incisional pain between two randomized groups—an intervention and a control.DesignMixed-methods design; quantitative data achieved via a randomized controlled trial, with qualitative data collected on binder use. The primary variable was oxycodone (in milligrams) required during the first 48 hours after birth, and the secondary variable was incisional pain levels measured on Postoperative Days 1 and 2.SettingAcute-care community hospital in Wheat Ridge, Colorado, and an acute care urban hospital in Denver, Colorado.ParticipantsA total of 220 individuals in the postpartum period after having cesarean birth.Interventions/MeasurementsParticipants were randomized to the intervention group (binder) or the control group (no binder). Data were collected on opioid usage for the first 48 hours. Participants in both groups were asked to rate their incisional pain on Postoperative Day 1 (24 hours after birth) and Postoperative Day 2 (48 hours after birth). Participants in the binder group were also asked to provide feedback on their experience wearing the binder.ResultsA total of 196 participants completed the study. The overall amount of oxycodone taken by individuals in the binder group was lower than that in the control group, but the difference was not statistically significant (p = .10). Pain scores in the binder group were significantly lower on Day 2 compared with the control group (p = .002). The majority of individuals in the binder group provided positive feedback about their experience wearing the binder.ConclusionIndividuals routinely receive medications to assist with pain management postoperatively. Because of growing concerns related to the nation’s opioid addiction crisis, there is interest in using multimodal treatments to achieve adequate pain control for individuals postoperatively. Abdominal binders are a low-cost intervention to assist with pain management and, given the results of this study, seem like a reasonable option to consider.  相似文献   
4.
Noninvasive imaging of cardiac fibrosis is important for early diagnosis and intervention in chronic heart diseases. Here, we investigated whether noninvasive, contrast agent-free MRI T2-mapping can quantify myocardial fibrosis in preclinical models of aging and pressure overload. Myocardial fibrosis and remodeling were analyzed in two animal models: (i) aging (15-month-old male CF-1 mice vs. young 6- to 8-week-old mice), and (ii) pressure overload (PO; by transverse aortic constriction in 4- to 5-month-old male C57BL/6 mice vs. sham-operated for 14 days). In vivo T2-mapping was performed by acquiring data during the isovolumic and early diastolic phases, with a modified respiratory and ECG-triggered multiecho TurboRARE sequence on a 7-T MRI. Cine MRI provided cardiac morphology and function. A quantitative segmentation method was developed to analyze the in vivo T2-maps of hearts at midventricle, apex, and basal regions. The cardiac fibrosis area was analyzed ex vivo by picro sirius red (PSR) staining. Both aged and pressure-overloaded hearts developed significant myocardial contractile dysfunction, cardiac hypertrophy, and interstitial fibrosis. The aged mice had two phenotypes, fibrotic and mild-fibrotic. Notably, the aged fibrotic subgroup and the PO mice showed a marked decrease in T2 relaxation times (25.3 ± 0.6 in aged vs. 29.9 ± 0.7 ms in young mice, p = 0.002; and 24.3 ± 1.7 in PO vs. 28.7 ± 0.7 ms in shams, p = 0.05). However, no significant difference in T2 was detected between the aged mild-fibrotic subgroup and the young mice. Accordingly, an inverse correlation between myocardial fibrosis percentage (FP) and T2 relaxation time was derived (R2 = 0.98): T2 (ms) = 30.45 – 1.05 × FP. Thus, these results demonstrate a statistical agreement between T2-map–quantified fibrosis and PSR staining in two different clinically relevant animal models. In conclusion, T2-mapping MRI is a promising noninvasive contrast agent-free quantitative technique to characterize myocardial fibrosis.  相似文献   
5.
6.
7.
Background:We aim to evaluate the efficiency of Raman spectroscopy (RS) in diagnosing suspected patients with intrahepatic cholangiocarcinoma (ICC), manifested by diagnostic sensitivity, specificity, and accuracy.Methods:We will research widely the articles concerning the use of RS in ICC through authenticated database including PubMed/Medline, EMBASE, Web of Science, Ovid, Web of Knowledge, Cochrane Library, and CNKI between January 2012 and November 2020, retrieving at least 1500 spectra with strict criteria. This study will be carried out in accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We are going to summarize the test performance using random effects models.Results:Based on the pooled sensitivity, specificity, and diagnostic accuracy, we intend to provide the relative diagnostic efficiency in ICC through RS.Conclusion:Through this systematic review and meta-analysis, we intend to provide the pooled sensitivity, specificity and diagnostic accuracy of RS in the diagnosis of suspected ICC. Other parameters like positive likelihood ratios (LR), negative LR, diagnostic odds ratio (DOR), and area under curve (AUC) of the summary receiver operating characteristics (SROC) curve will also be calculated and related figures will be drawn to help illustrate the efficacy of RS in the diagnosis of ICC.  相似文献   
8.
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   
9.
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   
10.
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   
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