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   261145篇
  免费   20938篇
  国内免费   8056篇
耳鼻咽喉   1391篇
儿科学   9969篇
妇产科学   2246篇
基础医学   23813篇
口腔科学   3771篇
临床医学   28666篇
内科学   67510篇
皮肤病学   3070篇
神经病学   27013篇
特种医学   7610篇
外国民族医学   4篇
外科学   21008篇
综合类   36908篇
现状与发展   32篇
一般理论   11篇
预防医学   18902篇
眼科学   3303篇
药学   18908篇
  206篇
中国医学   11920篇
肿瘤学   3878篇
  2024年   519篇
  2023年   4974篇
  2022年   7272篇
  2021年   13208篇
  2020年   12623篇
  2019年   9868篇
  2018年   9687篇
  2017年   9557篇
  2016年   9807篇
  2015年   9541篇
  2014年   18121篇
  2013年   19935篇
  2012年   14932篇
  2011年   16256篇
  2010年   12824篇
  2009年   12394篇
  2008年   12336篇
  2007年   12228篇
  2006年   10839篇
  2005年   9205篇
  2004年   7778篇
  2003年   6831篇
  2002年   5768篇
  2001年   5090篇
  2000年   4203篇
  1999年   3738篇
  1998年   3471篇
  1997年   3135篇
  1996年   2777篇
  1995年   2465篇
  1994年   2323篇
  1993年   1984篇
  1992年   1867篇
  1991年   1647篇
  1990年   1314篇
  1989年   1178篇
  1988年   1074篇
  1987年   973篇
  1986年   852篇
  1985年   1009篇
  1984年   886篇
  1983年   537篇
  1982年   633篇
  1981年   534篇
  1980年   441篇
  1979年   359篇
  1978年   287篇
  1977年   249篇
  1976年   219篇
  1975年   103篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
《Ticks and Tick》2020,11(6):101540
Powassan virus (POWV) is a tickborne flavivirus discovered in Ontario, Canada in 1958 that causes long-term neurological sequelae in about half the reported cases and death in a little more than 10 % of cases. The incidence of POWV disease is rising in the United States but there is limited understanding of the scope and causes of recent changes in POWV epidemiology. We focus on quantifying the increase in human POWV disease incidence and infection prevalence in the United States. We also examine differences in the frequency of symptomatic cases and asymptomatic or mildly symptomatic cases, as well as limitations in national and state surveillance for POWV infection. We searched SCOPUS for all articles containing original POWV prevalence research, case studies, or literature reviews published in English. Case studies were supplemented by Morbidity and Mortality Weekly Report POWV data from the Centers for Disease Control and Prevention (CDC) and surveillance information from state health department websites. An increase in the number of POWV cases has been reported in the United States over the past 50 yr, and the geographic range of human POWV cases has expanded. The age distribution of symptomatic POWV cases has shifted, with significantly more individuals over 40 yr old being diagnosed after 1998. The emergence of POWV is due in large part to: (i) a change in transmission of POWV from a vector that rarely bites people (Ixodes cookei) to a new vector that often bites people (Ixodes scapularis) and has expanded its geographic range, (ii) enhanced surveillance efforts for arboviruses, and (iii) a greater awareness of POWV infection.  相似文献   
82.
83.
Hailey–Hailey disease (HHD), also known as benign familial pemphigus, is an autosomal dominant skin condition that affects the adhesion of epidermal keratinocytes. Although the initial manifestation of flaccid vesicles on erythematous or normal skin in flexure sites frequently goes unnoticed, large, macerated, exudative plaques of superficial erosions with crusting are observed at the time of diagnosis. There is no specific treatment for HHD, and most cases are symptomatically supported. However, infrared laser ablation has been somewhat helpful. We present a case successfully treated with fractional CO2 laser showing a long-term favourable outcome and no adverse effects. Thus, this modality could be an alternative to full ablation for this condition.  相似文献   
84.
85.
Plasma provided by COVID-19 convalescent patients may provide therapeutic relief as the number of COVID-19 cases escalates steeply worldwide. Prior findings in various viral respiratory diseases including SARS-CoV-related pneumonia suggest that convalescent plasma can reduce mortality, although formal proof of efficacy is still lacking. By reducing viral spread early on, such an approach may possibly downplay subsequent immunopathology. Identifying, collecting, qualifying and preparing plasma from convalescent patients with adequate SARS-CoV-2-neutralizing Ab titres in an acute crisis setting may be challenging, although well within the remit of most blood establishments. Careful clinical evaluation should allow to quickly establish whether such passive immunotherapy, administered at early phases of the disease in patients at high risk of deleterious evolution, may reduce the frequency of patient deterioration, and thereby COVID-19 mortality.  相似文献   
86.
Objective: Report efficacy findings from three clinical trials (one phase 2 and two phase 3 [OPUS-1, OPUS-2]) of lifitegrast ophthalmic solution 5.0% for treatment of dry eye disease (DED).

Research design and methods: Three 84-day, randomized, double-masked, placebo-controlled trials. Adults (≥18 years) with DED were randomized (1:1) to lifitegrast 5.0% or matching placebo. Changes from baseline to day 84 in signs and symptoms of DED were analyzed.

Main outcome measures: Phase 2, pre-specified endpoint: inferior corneal staining score (ICSS; 0–4); OPUS-1, coprimary endpoints: ICSS and visual-related function subscale (0–4 scale); OPUS-2, coprimary endpoints: ICSS and eye dryness score (EDS, VAS; 0–100).

Results: Fifty-eight participants were randomized to lifitegrast 5.0% and 58 to placebo in the phase 2 trial; 293 to lifitegrast and 295 to placebo in OPUS-1; 358 to lifitegrast and 360 to placebo in OPUS-2. In participants with mild-to-moderate baseline DED symptomatology, lifitegrast improved ICSS versus placebo in the phase 2 study (treatment effect, 0.35; 95% CI, 0.05–0.65; p?=?0.0209) and OPUS-1 (effect, 0.24; 95% CI, 0.10–0.38; p?=?0.0007). Among more symptomatic participants (baseline EDS ≥40, recent artificial tear use), lifitegrast improved EDS versus placebo in a post hoc analysis of OPUS-1 (effect, 13.34; 95% CI, 2.35–24.33; nominal p?=?0.0178) and in OPUS-2 (effect, 12.61; 95% CI, 8.51–16.70; p?<?0.0001).

Limitations: Trials were conducted over 12 weeks; efficacy beyond this period was not assessed.

Conclusions: Across three trials, lifitegrast improved ICSS in participants with mild-to-moderate baseline symptomatology in two studies, and EDS in participants with moderate-to-severe baseline symptomatology in two studies. Based on the overall findings from these trials, lifitegrast shows promise as a new treatment option for signs and symptoms of DED.  相似文献   
87.
Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates.  相似文献   
88.
89.
90.
目的探讨心达康滴丸联合盐酸地尔硫卓片治疗冠心病心绞痛的临床疗效。方法选择2018年7月—2019年7月在武汉市江夏区中医医院治疗的冠心病心绞痛患者94例,根据用药的差别分成对照组(47例)和治疗组(47例)。对照组口服盐酸地尔硫卓片,30mg/次,3次/d;治疗组在对照组基础上口服心达康滴丸,18粒/次,3次/d。两组患者均经4周治疗。观察两组患者临床疗效,同时比较治疗前后两组患者心绞痛发作次数和持续时间,临床症状积分、SAQ和GQOLI-74评分,血清C反应蛋白(CRP)、S100钙结合蛋白A12(S100A12)、白细胞介素-18(IL-18)、妊娠相关血清蛋白A(PAPP-A)、内皮素-1(ET-1)和肌钙蛋白I(CTnI)水平及心功能。结果治疗后,对照组和治疗组临床有效率分别为80.85%和97.87%,两组比较差异具有统计学意义(P0.05)。治疗后,两组患者心绞痛发作次数及持续时间都显著改善降低(P0.05),且治疗组比对照组改善更显著(P0.05)。治疗后,两组患者SAQ积分和GQOLI-74评分均明显升高,而临床症状积分明显降低(P0.05),且治疗组这些评分明显好于对照组(P0.05)。治疗后,两组患者血清CRP、S100A12、IL-18、PAPP-A、ET-1、CTnI水平均明显降低(P0.05),且治疗组明显低于对照组(P0.05)。治疗后,两组患者左心室射血分数(LVEF)和心排血量(CO)均升高,而左室收缩末期内径(LVESD)明显降低(P0.05),且治疗组LVEF、CO和LVESD比对照组改善更明显(P0.05)。结论心达康滴丸联合盐酸地尔硫卓片治疗冠心病心绞痛可明显改善患者临床症状,改善生活质量,具有一定的临床推广应用价值。  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