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   80961篇
  免费   6167篇
  国内免费   1129篇
耳鼻咽喉   741篇
儿科学   2488篇
妇产科学   1831篇
基础医学   11451篇
口腔科学   991篇
临床医学   9942篇
内科学   14189篇
皮肤病学   1560篇
神经病学   7149篇
特种医学   2609篇
外国民族医学   43篇
外科学   8414篇
综合类   2983篇
现状与发展   7篇
一般理论   108篇
预防医学   8780篇
眼科学   1501篇
药学   6012篇
  15篇
中国医学   1141篇
肿瘤学   6302篇
  2024年   89篇
  2023年   791篇
  2022年   812篇
  2021年   3013篇
  2020年   1774篇
  2019年   2378篇
  2018年   2746篇
  2017年   2077篇
  2016年   2383篇
  2015年   2880篇
  2014年   3745篇
  2013年   4783篇
  2012年   6795篇
  2011年   6978篇
  2010年   3866篇
  2009年   3301篇
  2008年   5388篇
  2007年   5233篇
  2006年   4762篇
  2005年   4606篇
  2004年   3973篇
  2003年   3495篇
  2002年   3161篇
  2001年   1006篇
  2000年   925篇
  1999年   886篇
  1998年   718篇
  1997年   564篇
  1996年   459篇
  1995年   462篇
  1994年   393篇
  1993年   327篇
  1992年   288篇
  1991年   305篇
  1990年   257篇
  1989年   203篇
  1988年   193篇
  1987年   153篇
  1986年   169篇
  1985年   151篇
  1984年   146篇
  1983年   131篇
  1982年   147篇
  1981年   171篇
  1980年   120篇
  1979年   92篇
  1978年   73篇
  1977年   73篇
  1976年   68篇
  1974年   71篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
目的探讨脊髓小脑共济失调2型(SCA2)致病基因ATXN2异常等位基因中间重复个体的表型和分子遗传学特点。方法针对2005—2018年中日友好医院神经科运动障碍与神经遗传病研究中心收集的1383个常染色体显性遗传共济失调家系的先证者和部分家系成员,采用荧光标记毛细管电泳片段分析方法进行动态突变检测,对携带ATXN2基因中间重复的个体进行临床表型和遗传特征分析。结果共检出163个家系(包含先证者和家系成员共203人)携带异常扩展的ATXN2基因CAG重复序列,其中93个家系中有107例的异常扩展等位基因重复次数在29~34次之间。在其中的20个亲子对中,父系遗传16个,异常等位基因的代间扩展增加0~28次,母系遗传4个,异常等位基因的代间扩展增加0~4次。结论对于临床拟诊SCA2家系患者,需对其亲代或成年子代个体进行ATXN2基因检测,以免漏诊。动态突变基因检测有助于识别中间重复的个体,对明确家系致病基因和遗传咨询至关重要。  相似文献   
2.
3.
Emergency Medicine staff in Australia and New Zealand are at the forefront of the healthcare response to COVID‐19. This article describes a well‐being plan for ED staff that has been devised to mitigate against the negative psychological impact of the COVID‐19 pandemic.  相似文献   
4.
目的总结不同类型硬膜下积液治疗经验。 方法对解放军总医院第六医学中心神经外科自2009年1月至2014年10月手术治疗并完整随访的27例硬膜下积液患者进行回顾性分析。根据术前影像学特征鉴别积液是否为血性,将患者分为血性硬膜下积液患者(9例)和非血性硬膜下积液患者(18例)。根据积液是否为血性选择个性化治疗方案,观察其疗法。 结果9例血性硬膜下积液患者接受钻孔外引流手术,8例积液消退,另外1例无效,之后接受硬膜下腹腔分流后治愈。非血性硬膜下积液患者中14例接受硬膜下腹腔分流,12例有效,2例术后出现脑积水,经脑室-腹腔分流术治愈;2例术前合并脑积水接受脑室-腹腔分流术,均有效;另外2例最初接受积液外引流,无效,之后行硬膜下腹腔分流后积液消退。 结论对于硬膜下积液患者,术前需仔细评估积液是否为血性,是否合并脑积水。血性积液采取钻孔外引流,非血性积液采取硬膜下腹腔分流,合并脑积水的积液采取脑室-腹腔分流手术方式,给予个体化治疗,可获得满意疗效。  相似文献   
5.
6.

Objectives

Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.

Methods

Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.

Results

A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.

Conclusions

Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight.  相似文献   
7.
The Combined Aerobic and Resistance Exercise (CARE) Trial compared different types and doses of exercise performed during breast cancer chemotherapy. Here, we report the longer-term follow-up of patient-reported outcomes, health-related fitness and exercise behavior at 6, 12 and 24 months postintervention. A multicenter trial in Canada randomized 301 breast cancer patients initiating chemotherapy to thrice weekly, supervised exercise consisting of a standard dose of 25–30 min of aerobic exercise (STAN; n = 96), a higher dose of 50–60 min of aerobic exercise (HIGH; n = 101) or a combined dose of 50–60 min of aerobic and resistance exercise (COMB; n = 104) performed for the duration of chemotherapy (median of 17 weeks). Primary outcomes were patient-reported outcomes including quality of life, cancer-related symptoms and psychosocial outcomes. Secondary outcomes were objective health-related fitness (assessed at 12 months only) and self-reported exercise behavior. A total of 269 (89.4%) participants completed patient-reported outcomes at all three follow-up time points and 263 (87.4%) completed the health-related fitness assessment at 12-month follow-up. COMB was significantly superior to (i) STAN for sleep quality at 6-month follow-up (p = 0.027); (ii) HIGH for upper body muscular endurance at 12-month follow-up (p = 0.020); and (iii) HIGH for meeting the resistance exercise guideline at 6-month follow-up (p = 0.006). Moreover, self-reported meeting of the combined exercise guideline during follow-up was significantly associated with better patient-reported outcomes and health-related fitness. Performing combined exercise during and after breast cancer chemotherapy may result in better longer-term patient-reported outcomes and health-related fitness compared to performing aerobic exercise alone.  相似文献   
8.
9.
10.
Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most individuals who have a fragility fracture. Bone fragility can manifest in different forms, and a “one-size-fits-all” approach to diagnosis and management of osteoporosis may not be suitable. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured. In this study, we propose that there are common combinations of bone properties, referred to as phenotypes, that are predisposed to different levels of fracture risk. Using HR-pQCT data from a multinational cohort (n = 5873, 71% female) between 40 and 96 years of age, we employed fuzzy c-means clustering, an unsupervised machine-learning method, to identify phenotypes of bone microarchitecture. Three clusters were identified, and using partial correlation analysis of HR-pQCT parameters, we characterized the clusters as low density, low volume, and healthy bone phenotypes. Most males were associated with the healthy bone phenotype, whereas females were more often associated with the low volume or low density bone phenotypes. Each phenotype had a significantly different cumulative hazard of major osteoporotic fracture (MOF) and of any incident osteoporotic fracture (p < 0.05). After adjustment for covariates (cohort, sex, and age), the low density followed by the low volume phenotype had the highest association with MOF (hazard ratio = 2.96 and 2.35, respectively), and significant associations were maintained when additionally adjusted for femoral neck aBMD (hazard ratio = 1.69 and 1.90, respectively). Further, within each phenotype, different imaging biomarkers of fracture were identified. These findings suggest that osteoporotic fracture risk is associated with bone phenotypes that capture key features of bone deterioration that are not distinguishable by aBMD. © 2021 American Society for Bone and Mineral Research (ASBMR).  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