全文获取类型
收费全文 | 2797篇 |
免费 | 315篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 70篇 |
妇产科学 | 30篇 |
基础医学 | 173篇 |
口腔科学 | 79篇 |
临床医学 | 331篇 |
内科学 | 1032篇 |
皮肤病学 | 123篇 |
神经病学 | 110篇 |
特种医学 | 333篇 |
外国民族医学 | 21篇 |
外科学 | 179篇 |
综合类 | 22篇 |
预防医学 | 362篇 |
眼科学 | 23篇 |
药学 | 106篇 |
肿瘤学 | 123篇 |
出版年
2023年 | 50篇 |
2022年 | 16篇 |
2021年 | 18篇 |
2020年 | 44篇 |
2019年 | 25篇 |
2018年 | 63篇 |
2017年 | 38篇 |
2016年 | 48篇 |
2015年 | 64篇 |
2014年 | 105篇 |
2013年 | 140篇 |
2012年 | 86篇 |
2011年 | 91篇 |
2010年 | 93篇 |
2009年 | 119篇 |
2008年 | 109篇 |
2007年 | 135篇 |
2006年 | 131篇 |
2005年 | 106篇 |
2004年 | 96篇 |
2003年 | 83篇 |
2002年 | 86篇 |
2001年 | 98篇 |
2000年 | 105篇 |
1999年 | 81篇 |
1998年 | 81篇 |
1997年 | 102篇 |
1996年 | 89篇 |
1995年 | 72篇 |
1994年 | 71篇 |
1993年 | 66篇 |
1992年 | 42篇 |
1991年 | 39篇 |
1990年 | 56篇 |
1989年 | 63篇 |
1988年 | 45篇 |
1987年 | 55篇 |
1986年 | 53篇 |
1985年 | 49篇 |
1984年 | 20篇 |
1983年 | 17篇 |
1982年 | 28篇 |
1981年 | 32篇 |
1980年 | 20篇 |
1979年 | 20篇 |
1978年 | 9篇 |
1977年 | 16篇 |
1976年 | 17篇 |
1975年 | 12篇 |
1969年 | 5篇 |
排序方式: 共有3135条查询结果,搜索用时 31 毫秒
61.
Kahli Zietlow MD Leslie Dubin MSW Alethia Battles JD MSW Caroline Vitale MD 《Journal of the American Geriatrics Society》2022,70(11):3070-3079
Guardianship may pose an ethical dilemma for physicians, who must balance protecting vulnerable patients from potential safety concerns with respecting their autonomy. Older adults with dementia are particularly susceptible to loss of independence and the ability to participate in medical decision making. To have the capacity for medical decision making, individuals must understand relevant information, appreciate their circumstances, demonstrate reasoning, and express a consistent choice free from coercion. Although capacity assessments are usually task-specific, geriatricians and other specialists may be asked to comment on capacity more globally. These determinations may be used to support a Petition for the Appointment of a Guardian of a Legally Incapacitated Adult, the legal process of pursuing guardianship in probate court. Assigned guardians may be known to the incapacitated individual (e.g., a family member or friend) or may be professional guardians with no prior relationship to the ward. Guardians are encouraged to use substituted decision-making, taking into account the ward's previously expressed values and preferences. Although a number of viable alternatives to guardianship exist, numerous systemic barriers may prevent these from being fully explored. The ongoing need for guardianship should be periodically revisited and reassessed. Data about guardians and wards is shockingly sparse, as there are no centralized databases. Laws and regulations for guardianships vary significantly between states. Physicians can serve as important allies and advocates for patients with cognitive impairment at risk of incapacity, can help preserve their autonomy for as long as possible, and ensure appropriate protections are in place if the patient does lose their decision-making ability. 相似文献
62.
63.
John D. Piette Eve Kerr Caroline Richardson Michele Heisler 《Journal of diabetes science and technology》2008,2(1):15-23
Background
Like many patients with diabetes, Department of Veterans Affairs (VA) patients frequently fall short of self-management goals and experience multiple barriers to self-care. Health information technologies (HITs) may provide the tools that patients need to manage their illness under the direction of their primary care team.Methods
We describe several ongoing projects focused on HIT resources for self-management in VA. VA researchers are developing HITs that seek to bolster a variety of potential avenues for self-management support, including patients′ relationships with other patients, connections with their informal care networks, and communication with their health care teams.Results
Veterans Affairs HIT research projects are developing services that can address the needs of patients with multiple challenges to disease self-care, including multimorbidity, health literacy deficits, and limited treatment access. These services include patient-to-patient interactive voice response (IVR) calling systems, IVR assessments with feedback to informal caregivers, novel information supports for clinical pharmacists based on medication refill data, and enhanced pedometers.Conclusion
Large health care systems such as the VA can play a critical role in developing HITs for diabetes self-care. To be truly effective, these efforts should include a continuum of studies: observational research to identify barriers to self-management, developmental studies (e.g., usability testing), efficacy trials, and implementation studies to evaluate utility in real-world settings. VA HIT researchers partner with operations to promote the dissemination of efficacious services, and such relationships will be critical to move HIT innovations into practice. 相似文献64.
Liu SC; Palek J; Yi SJ; Nichols PE; Derick LH; Chiou SS; Amato D; Corbett JD; Cho MR; Golan DE 《Blood》1995,86(1):349-358
Southeast Asian ovalocytosis (SAO) is an asymptomatic trait characterized by rigid, poorly deformable red cells that resist invasion by several strains of malaria parasites. The underlying molecular genetic defect involves simple heterozygous state for a mutant band 3 protein, which contains a deletion of amino acids 400 through 408, linked with a Lys 56-to-Glu substitution (band 3-Memphis polymorphism). To elucidate the contribution of the mutant SAO band 3 protein to increased SAO red blood cell (RBC) rigidity, we examined the participation of the mutant SAO band 3 protein in increased band 3 attachment to the skeleton and band 3 oligomerization. We found first that SAO RBC skeletons retained more band 3 than normal cells and that this increased retention preferentially involved the mutant SAO band 3 protein. Second, SAO RBCs contained a higher percentage of band 3 oligomer-ankyrin complexes than normal cells, and these oligomers were preferentially enriched by the mutant SAO protein. At the ultrastructural level, the increased oligomer formation of SAO RBCs was reflected by stacking of band 3-containing intramembrane particles (IMP) into longitudinal strands. The IMP stacking was not reversed by treating SAO RBCs in alkaline pH (pH 11), which is known to weaken ankyrin-band 3 interactions, or by removing the cytoplasmic domain of band 3 from SAO membranes with trypsin. Finally, we found that band 3 protein in intact SAO RBCs exhibited a markedly decreased rotational mobility, presumably reflecting the increased oligomerization and the membrane skeletal association of the SAO band 3 protein. We propose that the mutant SAO band 3 has an increased propensity to form oligomers, which appear as longitudinal strands of IMP and exhibit increased association with membrane skeleton. This band 3 oligomerization underlies the increase in membrane rigidity by precluding membrane skeletal extension, which is necessary for membrane deformation. 相似文献
65.
66.
67.
68.
69.
70.
Bruno Scherrer S. Andrieu P.-J. Ousset G. Berrut J.-F. Dartigues B. Dubois F. Pasquier F. Piette P. Robert J. Touchon P. Garnier H. Mathiex-Fortunet B. Vellas The Guidage Study Group 《The journal of nutrition, health & aging》2015,19(10):1009-1011
Time-to-event analysis is frequently used in medical research to investigate potential diseasemodifying treatments in neurodegenerative diseases. Potential treatment effects are generally evaluated using the logrank test, which has optimal power and sensitivity when the treatment effect (hazard ratio) is constant over time. However, there is generally no prior information as to how the hazard ratio for the event of interest actually evolves. In these cases, the logrank test is not necessarily the most appropriate to use. When the hazard ratio is expected to decrease or increase over time, alternative statistical tests such as the Fleming-Harrington test, provide a better sensitivity. An example of this comes from a large, five-year randomised, placebo-controlled prevention trial (GuidAge) in 2854 community-based subjects making spontaneous memory complaints to their family physicians, which evaluated whether treatment with EGb761® can modify the risk of developing AD. The primary outcome measure was the time to conversion from memory complaint to Alzheimer’s type dementia. Although there was no significant difference in the hazard function of conversion between the two treatment groups according to the preplanned logrank test, a significant treatment-by-time interaction for the incidence of AD was observed in a protocol-specified subgroup analysis, suggesting that the hazard ratio is not constant over time. For this reason, additional post hoc analyses were performed using the Fleming-Harrington test to evaluate whether there was a signal of a late effect of EGb761®. Applying the Fleming-Harrington test, the hazard function for conversion to dementia in the placebo group was significantly different from that in the EGb761® treatment group (p = 0.0054), suggesting a late effect of EGb761®. Since this was a post hoc analysis, no definitive conclusions can be drawn as to the effectiveness of the treatment. This post hoc analysis illustrates the interest of performing another randomised clinical trial of EGb761® explicitly testing the hypothesis of a late treatment effect, as well as of using of better adapted statistical approaches for long term preventive trials when it is expected that prevention cannot have an immediate effect but rather a delayed effect that increases over time. 相似文献