全文获取类型
收费全文 | 1513篇 |
免费 | 156篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 69篇 |
妇产科学 | 21篇 |
基础医学 | 166篇 |
口腔科学 | 38篇 |
临床医学 | 204篇 |
内科学 | 313篇 |
皮肤病学 | 16篇 |
神经病学 | 69篇 |
特种医学 | 258篇 |
外科学 | 210篇 |
综合类 | 35篇 |
预防医学 | 79篇 |
眼科学 | 12篇 |
药学 | 98篇 |
中国医学 | 5篇 |
肿瘤学 | 80篇 |
出版年
2023年 | 9篇 |
2021年 | 21篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 32篇 |
2017年 | 18篇 |
2016年 | 30篇 |
2015年 | 30篇 |
2014年 | 41篇 |
2013年 | 41篇 |
2012年 | 38篇 |
2011年 | 42篇 |
2010年 | 43篇 |
2009年 | 73篇 |
2008年 | 54篇 |
2007年 | 29篇 |
2006年 | 37篇 |
2005年 | 23篇 |
2004年 | 37篇 |
2003年 | 42篇 |
2002年 | 34篇 |
2001年 | 30篇 |
2000年 | 39篇 |
1999年 | 29篇 |
1998年 | 57篇 |
1997年 | 55篇 |
1996年 | 66篇 |
1995年 | 51篇 |
1994年 | 52篇 |
1993年 | 57篇 |
1992年 | 32篇 |
1991年 | 17篇 |
1990年 | 26篇 |
1989年 | 36篇 |
1988年 | 49篇 |
1987年 | 43篇 |
1986年 | 44篇 |
1985年 | 30篇 |
1984年 | 23篇 |
1983年 | 20篇 |
1982年 | 30篇 |
1981年 | 21篇 |
1980年 | 18篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 20篇 |
1976年 | 19篇 |
1975年 | 18篇 |
1972年 | 6篇 |
1968年 | 11篇 |
排序方式: 共有1676条查询结果,搜索用时 15 毫秒
71.
van Gils FC; van Teeffelen ME; Neelis KJ; Hendrikx J; Burger H; van Leen RW; Knol E; Wagemaker G; Wognum AW 《Blood》1995,86(2):592-597
To understand the hematopoietic and nonhematopoietic responses to interleukin-3 (IL-3), expression of cell-surface IL-3 receptors (IL-3R) was examined on bone marrow (BM) cells and peripheral blood (PB) cells of rhesus monkeys during the course of in vivo IL-3 treatment. Whereas IL-3R expression is low in untreated monkeys, IL-3 administration led to a gradual increase in both low- and high-affinity binding sites for IL-3. This increase reflected the total number of cells expressing IL- 3Rs, as detected by flow cytometry using biotinylated IL-3. Most of these IL-3R+ cells in both BM and PB could be characterized as basophilic granulocytes that contained high levels of histamine. In contrast to the effect on these differentiated cells, IL-3 administration did not significantly alter the low level IL-3R expression on immature, CD34+ cells. Further flow cytometric analysis using biotinylated growth factors showed that the IL-3R+ basophils also expressed receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), but not for IL-6 or Kit ligand. These findings indicated that the IL-3R+ cells included neither monocytes, which express GM-CSFRs and IL-6Rs abundantly, nor mast cells, which express c- kit. By combining flow cytometric and Scatchard data, it was calculated that the basophils contain as many as 1 to 2 x 10(3) high-affinity IL- 3Rs and 15 to 30 x 10(3) low-affinity sites. The finding that in vivo IL-3 treatment leads to the production of large numbers of cells that express high levels of IL-3R and are capable of producing histamine provides an explanation for the often severe allergic reactions that occur during prolonged IL-3 administration. It also indicates that IL- 3, in addition to its direct effects on hematopoietic cells, may also stimulate hematopoiesis through the release of secondary mediators such as histamine by IL-3-responsive mature cells. 相似文献
72.
PURPOSE: The purpose of this study was to compare the sociodemographics, self-rated health, and involvement levels of family caregivers of residents with dementia in residential care/assisted living (RC/AL) versus nursing home settings. DESIGN AND METHODS: We conducted telephone interviews with the family caregivers most involved with 353 residents of 34 residential care and 10 nursing home facilities. We measured involvement by caregiver self-report of monthly out-of-pocket spending, involvement and burden ratings, and the frequency of engaging in eight specific care activities. Open-ended questions elicited areas in which caregivers preferred different involvement and ways the facility could facilitate involvement. RESULTS: Nursing home caregivers rated their health poorer than RC/AL caregivers, but there were no sociodemographic differences between the two. RC/AL caregivers rated both their perception of involvement and burden higher and engaged more frequently in monitoring the resident's health, well-being, and finances than did nursing home caregivers, although the reported time spent per week on care did not differ. IMPLICATIONS: RC/AL and nursing home caregivers to residents with dementia may tailor their care to fit the needs of the resident and setting. Results are discussed in relation to the Congruence Model of Person-Environment Fit. 相似文献
73.
74.
Jillian G. Buchan MS David M. Alvarado PhD Gabe Haller PhD Hyuliya Aferol BS Nancy H. Miller MD Matthew B. Dobbs MD Christina A. Gurnett MD PhD 《Clinical orthopaedics and related research》2014,472(10):3216-3225
Background
Adolescent idiopathic scoliosis (AIS) is a complex genetic disorder that causes spinal deformity in approximately 3% of the population. Candidate gene, linkage, and genome-wide association studies have sought to identify genetic variation that predisposes individuals to AIS, but the genetic basis remains unclear. Copy number variants are associated with several isolated skeletal phenotypes, but their role in AIS, to our knowledge, has not been assessed.Questions/Purposes
We determined the frequency of recurrent copy number rearrangements, chromosome aneuploidy, and rare copy number variants in patients with AIS.Methods
Between January 2010 and August 2014, we evaluated 150 patients with isolated AIS and spinal curvatures measuring 10° or greater, and 148 agreed to participate. Genomic copy number analysis was performed on patients and 1079 control subjects using the Affymetrix® Genome-wide Human SNP Array 6.0. After removing poor quality samples, 143 (97%) patients with AIS were evaluated for copy number variation.Results
We identified a duplication of chromosome 1q21.1 in 2.1% (N = 3/143) of patients with AIS, which was enriched compared with 0.09% (N = 1/1079) of control subjects (p = 0.0057) and 0.07% (N = 6/8329) of a large published control cohort (p = 0.0004). Other notable findings include trisomy X, which was identified in 1.8% (N = 2/114) of female patients with AIS, and rearrangements of chromosome 15q11.2 and 16p11.2 that previously have been associated with spinal phenotypes. Finally, we report rare copy number variants that will be useful in future studies investigating candidate genes for AIS.Conclusions
Copy number variation and chromosomal aneuploidy may contribute to the pathogenesis of adolescent idiopathic scoliosis.Clinical Relevance
Chromosomal microarray may reveal clinically useful abnormalities in some patients with AIS. 相似文献75.
76.
77.
78.
Subgroup comparison of COVID-19 case and mortality with associated factors in Mississippi: findings from analysis of the first four months of public data
下载免费PDF全文
![点击此处可从《生物医学研究杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Zhang Lei McLeod Stephanie T. Vargas Rodolfo Liu Xiaojian Young Dorthy K. Dobbs Thomas E. 《生物医学研究杂志》2020,34(6):446-457
We compared subgroup differences in COVID-19 case and mortality and investigated factors associated with case and mortality rate (MR) measured at the county level in Mississippi. Findings were based on data published by the Mississippi State Department of Health between March 11 and July 16, 2020. The COVID-19 case rate and case fatality rate (CFR) differed by gender and race, while MR only differed by race. Residents aged 80 years or older and those who live in a non-metro area had a higher case rate, CFR, and MR. After controlling for selected factors, researchers found that the percent of residents who are obese, low income, or with certain chronic conditions were associated with the county COVID-19 case rate, CFR, and/or MR, though some were negatively related. The findings may help the state to identify counties with higher COVID-19 case rate, CFR, and MR based on county demographics and the degree of its chronic conditions. 相似文献
79.
Juliana Maier Camila Silveira Sfreddo Ana Paula Pereira Reiniger Karla Zanini Kantorski Ulf ME Wikesj Carlos Heitor Cunha Moreira 《International dental journal》2021,71(2):127
BackgroundPeriodontal disease is a major cause of tooth loss. Few studies have evaluated the residual area of the periodontal ligament in extracted teeth and, to the best of our knowledge, none from Latin America have done so regarding indications for extraction. The aim of this study was to evaluate the residual periodontal ligament (RPL) with respect to indication for extraction in a sample of teeth from a Brazilian Public Health Service district.Materials and methodsAll teeth extracted within the Public Health Service district of Santa Maria, Brazil, over a 5-month period were requested for analysis. A total of 414 teeth eligible for measurement were stained and evaluated for RPL using a stereo microscope. Participating Public Health Service dentists completed a questionnaire detailing demographic variables and indication for each extracted tooth. The percentage of RPL was determined for each tooth. Comparisons of RPL between teeth extracted on periodontal versus other indications were made using the Mann-Whitney test.ResultsRPL averaged 34.8% for teeth extracted on periodontal indications versus 79.5% for other teeth (P ≤ 0.001). When considering teeth with an RPL ≥ 30% as possible to maintain, 189 (76%) of the teeth extracted on periodontal indications could have been maintained. When RPL cut-off limits of ≥ 40% or ≥ 50% are applied, 93 (37%) and 43 (17%) teeth, respectively, could have been maintained.ConclusionThis study suggests that strictly based on RPL, a large number of teeth extracted on periodontal indications conceivably could be maintained.Key words: Cross-sectional studies, Prognosis, Tooth extraction, Tooth loss 相似文献
80.
Patience ME Ocansey Irene A Kretchy Genevieve C Aryeetey Kofi Agyabeng Justice Nonvignon 《Ghana medical journal》2021,55(3):173
ObjectiveThis study assessed levels of anxiety, depression, and stress among family caregivers of children and adolescents with mental disorders in Ghana and the implication on medication adherence.DesignA cross-sectional study.SettingThe study was conducted at the outpatient departments of the three main public psychiatric hospitals in Ghana.ParticipantsTwo hundred and ten non-paid family caregivers of children and adolescents with mental disorders were recruited for this study.Main Outcome MeasureThe study assessed symptoms of anxiety, depression and stress among the caregivers and estimated caregiver-reported medication adherence.ResultsAbout 56.2%, 66.2% and 78% of the caregivers experienced severe anxiety, severe depression and moderate to severe stress symptoms respectively. From the multiple logistic regression model, while anxiety was significantly affected by religion and education, depression was influenced by sex, age, marital status, proximity to facility, and employment status. Female caregivers had about four times higher odds of being depressed compared to male caregivers (aOR: 3.81, 95% CI: 1.66 – 8.75). The caregiver-reported medication adherence was 11.9%. Anxiety was significantly predictive of medication adherence.ConclusionMost family caregivers of children and adolescents with mental disorders experienced symptoms of anxiety, depression and stress with anxiety having implications for medication adherence. The study findings underscore the need to consider psychological characteristics of caregivers and the provision of mental health support for them, as part of the routine health care for children and adolescents with mental disorders.FundingNone indicated 相似文献