收费全文 | 1124篇 |
免费 | 92篇 |
国内免费 | 2篇 |
耳鼻咽喉 | 3篇 |
儿科学 | 48篇 |
妇产科学 | 17篇 |
基础医学 | 142篇 |
口腔科学 | 12篇 |
临床医学 | 202篇 |
内科学 | 289篇 |
皮肤病学 | 5篇 |
神经病学 | 73篇 |
特种医学 | 28篇 |
外科学 | 119篇 |
综合类 | 5篇 |
一般理论 | 2篇 |
预防医学 | 154篇 |
眼科学 | 16篇 |
药学 | 65篇 |
肿瘤学 | 38篇 |
2023年 | 12篇 |
2022年 | 15篇 |
2021年 | 46篇 |
2020年 | 18篇 |
2019年 | 39篇 |
2018年 | 31篇 |
2017年 | 26篇 |
2016年 | 41篇 |
2015年 | 25篇 |
2014年 | 32篇 |
2013年 | 50篇 |
2012年 | 113篇 |
2011年 | 96篇 |
2010年 | 38篇 |
2009年 | 39篇 |
2008年 | 57篇 |
2007年 | 51篇 |
2006年 | 47篇 |
2005年 | 42篇 |
2004年 | 49篇 |
2003年 | 47篇 |
2002年 | 40篇 |
2001年 | 22篇 |
2000年 | 42篇 |
1999年 | 26篇 |
1998年 | 20篇 |
1997年 | 10篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1992年 | 19篇 |
1991年 | 15篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1960年 | 1篇 |
Background
In pig‐to‐human xenotransplantation, interactions between human natural killer (NK) cells and porcine endothelial cells (pEC) are characterized by recruitment and cytotoxicity. Protection from xenogeneic NK cytotoxicity can be achieved in vitro by the expression of the non‐classical human leukocyte antigen‐E (HLA‐E) on pEC. Thus, the aim of this study was to analyze NK cell responses to vascularized xenografts using an ex vivo perfusion system of pig limbs with human blood.Methods
Six pig forelimbs per group, respectively, stemming from either wild‐type (wt) or HLA‐E/hCD46 double‐transgenic (tg) animals, were perfused ex vivo with heparinized human blood for 12 hours. Blood samples were collected at defined time intervals, cell numbers counted, and peripheral blood mononuclear cells analyzed for phenotype by flow cytometry. Muscle biopsies were analyzed for NK cell infiltration. In vitro NK cytotoxicity assays were performed using pEC derived from wt and tg animals as target cells.Results
Ex vivo, a strong reduction in circulating human CD45 leukocytes was observed after 60 minutes of xenoperfusion in both wt and tg limb groups. NK cell numbers dropped significantly. Within the first 10 minutes, the decrease in NK cells was more significant in the wt limb perfusions as compared to tg limbs. Immunohistology of biopsies taken after 12 hours showed less NK cell tissue infiltration in the tg limbs. In vitro, NK cytotoxicity against hCD46 single tg pEC and wt pEC was similar, while lysis of double tg HLA‐E/hCD46 pEC was significantly reduced. Finally, circulating cells of pig origin were observed during the ex vivo xenoperfusions. These cells expressed phenotypes mainly of monocytes, B and T lymphocytes, NK cells, as well as some activated endothelial cells.Conclusions
Ex vivo perfusion of pig forelimbs using whole human blood represents a powerful tool to study humoral and early cell‐mediated rejection mechanisms of vascularized pig‐to‐human xenotransplantation, although there are several limitations of the model. Here, we show that (i) transgenic expression of HLA‐E/hCD46 in pig limbs provides partial protection from human NK cell‐mediated xeno responses and (ii) the emergence of a pig cell population during xenoperfusions with implications for the immunogenicity of xenografts. 相似文献Purpose
Rupture-prone atherosclerotic plaques are characterized by accumulation of macrophages, which have shown to express somatostatin type 2 receptors. We aimed to investigate whether somatostatin receptor-targeting positron emission tomography (PET) tracers, [68Ga]DOTANOC, [18F]FDR-NOC, and [68Ga]DOTATATE, can detect inflamed atherosclerotic plaques.Procedures
Atherosclerotic IGF-II/LDLR?/?ApoB100/100 mice were studied in vivo and ex vivo for tracer uptake into atherosclerotic plaques. Furthermore, [68Ga]DOTANOC and [68Ga]DOTATATE were compared in a head-to-head setting for in vivo PET/X-ray computed tomography (CT) imaging characteristics.Results
Ex vivo uptake of [68Ga]DOTANOC and [68Ga]DOTATATE in the aorta was higher in atherosclerotic mice compared to control C57Bl/6N mice, while the aortic uptake of [18F]FDR-NOC showed no genotype difference. Unlike [18F]FDR-NOC, [68Ga]DOTANOC and [68Ga]DOTATATE showed preferential binding to atherosclerotic plaques with plaque-to-wall ratio of 1.7?±?0.3 and 2.1?±?0.5, respectively. However, the aortic uptake and aorta-to-blood ratio of [68Ga]DOTANOC were higher compared to [68Ga]DOTATATE in in vivo PET/CT imaging.Conclusion
Our results demonstrate superior applicability for [68Ga]DOTANOC and [68Ga]DOTATATE in the detection of atherosclerotic plaques compared to [18F]FDR-NOC.Method: Ten adults aged over 40 years with cerebral palsy participated in a group-based 10-week progressive resistance strength-training programme in a community gymnasium. After the programme, each participant was interviewed using an in-depth semi-structured format and the results coded thematically.
Results: Participants perceived that their strength, and ability to perform everyday activities had improved. However, the main benefit for participants was enjoyment and social interaction. The only negative perceptions related to fatigue, short-term muscle soreness and a feeling that they had not improved as much as they had expected.
Conclusions: Enjoyment, a factor that can promote adherence and sustainability, was a key benefit of this strength-training programme for adults with cerebral palsy that led to perceptions of increased strength and physical functioning. These findings suggest that exercise programmes for adults with cerebral palsy should be conducted in a group in the community, thereby promoting community inclusion. In addition, it is important to provide education to participants about the normal responses and expectations of an exercise programme. 相似文献
Materials and methods: A historical cohort of Finnish workers with a severe occupational injury during 2008 (N?=?11,585) were followed up annually on the outcomes of return to work over a 5-year observation period. We examined transition probabilities from one life situation to another with Markov chain analysis, and applied logistic regression with generalized estimating equations to assess the effect of register-based determinants on return to work.
Results: Within the five anniversaries, 85% of the injured were working, 9% were unable to work (fully or partly) and 2% received rehabilitation. Age, gross annual income, type of work, injured body part, injury type and the injured’s annual condition subsequent to the work injury were significant determinants of return to work.
Conclusions: The probability of return to work decreased with time, but, on average, one-fifth of the injured workers succeeded in return to work after being unable to work on the previous anniversary, which indicates that it is worthwhile to conduct efforts for this target group in order to promote return to work.
- Implications for Rehabilitation
The current life situation of the injured should be taken into account when promoting return to work, as it is a strong predictor of later working after a serious occupational injury.
Rehabilitation and return to work programs should start in time due to declining return to work rates as the disability continues.
Return to work on a part-time basis could be a good option during the early phases of recovery, since a notable proportion of those partly unable to work on the first anniversary returned later to full-time workers.
The probability of recovery is relatively high even for those with long-term disabilities, so the promotion of return to work is highly recommended also for this target group.