全文获取类型
收费全文 | 4068篇 |
免费 | 270篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 106篇 |
妇产科学 | 76篇 |
基础医学 | 555篇 |
口腔科学 | 76篇 |
临床医学 | 423篇 |
内科学 | 945篇 |
皮肤病学 | 57篇 |
神经病学 | 518篇 |
特种医学 | 62篇 |
外国民族医学 | 1篇 |
外科学 | 420篇 |
综合类 | 38篇 |
一般理论 | 1篇 |
预防医学 | 380篇 |
眼科学 | 41篇 |
药学 | 264篇 |
中国医学 | 6篇 |
肿瘤学 | 358篇 |
出版年
2023年 | 40篇 |
2022年 | 88篇 |
2021年 | 163篇 |
2020年 | 94篇 |
2019年 | 129篇 |
2018年 | 141篇 |
2017年 | 95篇 |
2016年 | 117篇 |
2015年 | 122篇 |
2014年 | 191篇 |
2013年 | 197篇 |
2012年 | 330篇 |
2011年 | 332篇 |
2010年 | 159篇 |
2009年 | 178篇 |
2008年 | 231篇 |
2007年 | 253篇 |
2006年 | 249篇 |
2005年 | 187篇 |
2004年 | 196篇 |
2003年 | 202篇 |
2002年 | 177篇 |
2001年 | 26篇 |
2000年 | 32篇 |
1999年 | 30篇 |
1998年 | 27篇 |
1997年 | 28篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 19篇 |
1993年 | 17篇 |
1992年 | 12篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 13篇 |
1987年 | 16篇 |
1986年 | 10篇 |
1985年 | 15篇 |
1984年 | 13篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1979年 | 9篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1974年 | 10篇 |
1969年 | 14篇 |
1968年 | 13篇 |
1967年 | 9篇 |
排序方式: 共有4352条查询结果,搜索用时 15 毫秒
61.
Grigorios Kotronoulas Yvonne Wengström Nora Kearney 《Journal of pain and symptom management》2013,45(3):579-594
ContextAlterations in sleep-wake patterns of care recipients and their informal caregivers are common in the context of a chronic illness. Given the current notion that sleep may be regulated within and affected by close human relationships, concurrent and interrelated sleep problems may be present in care recipient-caregiver dyads.ObjectivesTo critically analyze evidence regarding concurrent sleep patterns or changes in care recipient-caregiver dyads in the context of a chronic illness and address methodological and research gaps.MethodsUsing a wide range of key terms and synonyms, three electronic databases (Medline, CINAHL, and Embase) were systematically searched for the period between January 1990 and July 2011.ResultsTen studies met prespecified selection criteria and were included for analysis. Study quality was fair to good on average. Seven studies were conducted in the context of dementia or Parkinson's disease, two in the context of cancer, and one study included a group of community elders with mixed related comorbidities and their informal caregivers. Bidirectional associations in the sleep of care recipient-caregiver dyads seem to exist. Concurrent and comparable nocturnal sleep disruptions also may be evident. Yet, inconsistencies in the methods implemented, and the samples included, as well as uncertainty regarding factors coaffecting sleep, still preclude safe conclusions to be drawn on.ConclusionThe dyadic investigation of sleep is a promising approach to the development of truly effective interventions to improve sleep quality of care recipients and their caregivers. Nevertheless, more systematic, longitudinal dyadic research is warranted to augment our understanding of co-occurrence and over time changes of sleep problems in care recipient-caregiver dyads, as well as to clarify covariates/factors that appear to contribute to these problems within the dyad and across time and context of illness. 相似文献
62.
63.
Laura Vandoni Ali G?khan Demir Barbara Previtali Nora Lecis Daniele Ugues 《Materials》2012,5(11):2360-2382
In heavy loaded mating components, such as sliders and sliding bearings, guaranteeing the efficiency of lubricant films for long times during severe service conditions is very complicated. In this work, the benefits deriving from the use of fiber laser sources for surface texturing of very thin TiN coatings in severe wear working conditions were demonstrated. Evaluations of the laser textured dimples shape, geometry and density are given. Wear performance of the fiber laser textured surfaces was evaluated in discontinuous oil lubricated conditions with a flat contact. High normal load and low sliding speed were applied. Comparison tests were also performed on commercial TiN and WC/C coatings. In terms of average wear volume and maximum wear depth, Laser Surface Texturing of TiN provided respectively a 70% and a 45% reduction if compared to plain TiN. If compared to WC/C the wear resistance gains were lower but LST TiN maintained such benefits for longer wear runs. SEM analysis also revealed that the laser interaction provided a localized thermal cracking to the TiN coating. However, the sliding action caused very limited and localized coating fragmentation or delamination. 相似文献
64.
65.
Red grape (Vitis vinifera L.) flavonoids down‐regulate collagen type III expression after UV‐A in primary human dermal blood endothelial cells 下载免费PDF全文
Serena Di Francesco Monica Savio Nora Bloise Giovanni Borroni Lucia Anna Stivala Riccardo G. Borroni 《Experimental dermatology》2018,27(9):973-980
Red grape (Vitis vinifera L.) flavonoids including flavan‐3‐ols (eg, catechin and epicatechin), flavonols (eg, quercetin) and anthocyanins (eg, malvidin) exert anti‐inflammatory and antioxidant activities. In the skin they also have a photoprotective action, and their effects have been extensively investigated in keratinocytes, melanocytes and fibroblasts. Despite their known effects also on blood vasculature, little is known on their activities on human dermal blood endothelial cells (HDBECs), which are critically involved in skin homeostasis as well as in the pathogenesis of neoplastic and inflammatory skin diseases. We sought to study the biological effects of selected red grape flavonoids in preventing the consequences of ultraviolet (UV)‐A irradiation in vitro. Our results show that red grape flavonoids prevent UV‐A‐induced sICAM‐1 release in HDBECs, suggesting that this cell type could represent an additional target of the anti‐inflammatory activity of flavonoids. In addition, flavonoids effectively inhibited UV‐A‐induced synthesis of collagen type III at both RNA and protein level, indicating that dermal blood microvasculature could be actively involved in ECM remodelling as a consequence of skin photo‐ageing, and that this can be prevented by red grape flavonoids. 相似文献
66.
67.
68.
69.
70.
Nora Siupsinskiene Vilma Jurgutaviciute Inga Katutiene Dainius Janciauskas Saulius Vaitkus Kęstutis Adamonis 《European archives of oto-rhino-laryngology》2013,270(8):2283-2288
Clinical studies have shown that Helicobacter pylori can be found not only in the mucosa of the stomach, but in the pharyngeal and laryngeal regions as well. The aim of this prospective case-control study was to identify H. pylori infection in the biopsy material from the larynx of the patients suffering from benign laryngeal diseases (vocal fold polyps, laryngitis) and laryngeal cancer and to investigate the possible relationships between the laryngeal H. pylori and patients’ socio-demographic data and laryngopharyngeal reflux. The results of the biopsy material from 67 adult patients treated for benign laryngeal diseases and laryngeal cancer and 11 individuals of the control group revealed that H. pylori infection could be identified in more than one-third of the patients. In the majority of cases H. pylori was found in the patients with chronic laryngitis (45.5 %) and laryngeal cancer (46.2 %). The findings of these sub-groups significantly differed from those of the control group (9.1 %) (p < 0.05). No significant relationships between H. pylori infection found in the laryngeal region and patients’ demographic data, their unhealthy habits and reflux-related symptoms or signs were obtained. It could be concluded that H. pylori can colonize in the larynx of patients with benign laryngeal diseases and laryngeal cancer. To clarify the role of H. pylori as a risk factor for laryngeal diseases further research is needed. 相似文献