全文获取类型
收费全文 | 20440篇 |
免费 | 1811篇 |
国内免费 | 43篇 |
学科分类
医药卫生 | 22294篇 |
出版年
2023年 | 187篇 |
2022年 | 250篇 |
2021年 | 503篇 |
2020年 | 373篇 |
2019年 | 542篇 |
2018年 | 566篇 |
2017年 | 501篇 |
2016年 | 549篇 |
2015年 | 503篇 |
2014年 | 725篇 |
2013年 | 976篇 |
2012年 | 1377篇 |
2011年 | 1426篇 |
2010年 | 729篇 |
2009年 | 572篇 |
2008年 | 1097篇 |
2007年 | 1105篇 |
2006年 | 995篇 |
2005年 | 925篇 |
2004年 | 877篇 |
2003年 | 802篇 |
2002年 | 780篇 |
2001年 | 442篇 |
2000年 | 437篇 |
1999年 | 389篇 |
1998年 | 184篇 |
1997年 | 168篇 |
1996年 | 164篇 |
1995年 | 136篇 |
1994年 | 124篇 |
1993年 | 123篇 |
1992年 | 251篇 |
1991年 | 262篇 |
1990年 | 299篇 |
1989年 | 236篇 |
1988年 | 213篇 |
1987年 | 219篇 |
1986年 | 200篇 |
1985年 | 229篇 |
1984年 | 174篇 |
1983年 | 118篇 |
1982年 | 82篇 |
1981年 | 75篇 |
1979年 | 115篇 |
1978年 | 105篇 |
1977年 | 73篇 |
1975年 | 80篇 |
1974年 | 108篇 |
1973年 | 90篇 |
1972年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Joseph M. Northey Kate L. Pumpa Clare Quinlan Ashley Ikin Kellie Toohey Disa J. Smee Ben Rattray 《Journal of Science and Medicine in Sport》2019,22(5):580-585
Objectives
The current study investigated the effects of two exercise interventions on cognitive function amongst breast cancer survivors.Design
Pilot randomised-controlled trial.Methods
Seventeen female cancer survivors (mean: 62.9 ± 7.8 years) were randomised into three groups: high-intensity interval training (HIIT, n = 6); moderate-intensity continuous training (MOD, n = 5); or wait-list control (CON, n = 6). The HIIT and MOD groups exercised on a cycle ergometer 3 days/week for 12-weeks. Primary outcomes were cognitive function assessments utilising CogState. Secondary outcomes were resting middle cerebral artery blood flow velocity, cerebrovascular reactivity and aerobic fitness (VO2peak). Data were analysed with General Linear Mixed Models and Cohen’s d effect sizes were calculated.Results
All 17 participants who were randomised were available for follow-up analysis and adherence was similar for HIIT and MOD (78.7 ± 13.2% vs 79.4 ± 12.0%; p = 0.93). Although there were no significant differences in the cognitive and cerebrovascular outcomes, HIIT produced moderate to large positive effects in comparison to MOD and CON for outcomes including episodic memory, working memory, executive function, cerebral blood flow and cerebrovascular reactivity. HIIT significantly increased VO2peak by 19.3% (d = 1.28) and MOD had a non-significant 5.6% (d = 0.72) increase, compared to CON which had a 2.6% decrease.Conclusions
This study provides preliminary evidence that HIIT may be an effective exercise intervention to improve cognitive performance, cerebrovascular function and aerobic fitness in breast cancer survivors. Considering the sample size is small, these results should be confirmed through larger clinical trials. 相似文献2.
Interaction effects between the 5‐hydroxy tryptamine transporter‐linked polymorphic region (5‐HTTLPR) genotype and family conflict on adolescent alcohol use and misuse 下载免费PDF全文
3.
Fluid role boundaries: exploring the contribution of the advanced nurse practitioner to multi‐professional palliative care 下载免费PDF全文
4.
5.
6.
贺晓新 《结核与肺部疾病杂志》2006,1(3):153-156
科学研究的目标是创造和传播知识。这得通过对系统收集以及报告信息的批判性分析来完成。批判性分析始于一个简单的步骤,即在运用复杂统计学分析方法进行比较之前对所收集的数据进行深入检查。根据所收集的数据类型按照标准化方式进行统计学分析。在为解决研究问题而需采用合理、标准化步骤进行比较时,新知识就产生了,同时要避免错误的结论。在对数据进行仔细检查和分析之后,为了保证结论的正确性,再对数据进行一次批判性评论是非常重要的补充步骤。在科学文献中发表研究成果过程中涉及的同行评价对于传播新知识并保证其质量方面是一个非常重要的步骤。如果没有将研究成果发表供同行参考,这项研究就不算完整。 相似文献
7.
Nawf Sharief Judith E. Kingston Vanessa M. Wright Kate Costeloe 《Pediatric hematology and oncology》1991,8(4):323-327
We describe a familial case of Marfan's syndrome with associated intrathoracic stomach detected during the neonatal period. The patient developed a primitive leukemia at 3 months of age. Acute leukemia in a patient with Marfan's syndrome has not previously been reported. 相似文献
8.
William A. Kennedy II Ralph Buttyan Eduardo Garcia-Montes Carl A. Olsson Ihor S. Sawczuk 《Urology》1997,49(6):973-980
Objectives. Acute unilateral ureteral obstruction (UUO) results in ipsilateral hydronephrosis characterized by a decrease in epidermal growth factor (EGF) mRNA expression and EGF protein levels in the distal renal tubules. UUO results in programmed cell death with increases in the characteristic markers of apoptosis. To suppress the apoptotic response during UUO, recombinant EGF was administered during renal obstruction and the ensuing molecular and histologic changes were studied.Methods. Mature Sprague-Dawley rats underwent left ureteral obstruction and the kidneys were harvested at 24, 48, and 72 hours. Markers of apoptosis included DNA laddering pattern on agarose gel electrophoresis, in situ gap labeling of fragmented DNA for quantitative apoptotic body determination, polyadenylated mRNA expression of SGP-2, and in situ hybridization for sulfated glycoprotein-2 (SGP-2) mRNA. Studies were repeated in rats following administration of 10, 20, and 40 μg of subcutaneous recombinant EGF on a daily basis after UUO.Results. Subcutaneous injection of EGF into unilaterally obstructed rats promotes renal tubular epithelial cell regeneration, as demonstrated by increased cortical mitotic activity. Systemic EGF supplementation in these unilaterally obstructed rats also resulted in a decrease in the intensity of the DNA laddering pattern associated with renal tubular apoptosis. An in situ labeling procedure to identify apoptotic nuclei in the ureterally obstructed kidneys revealed a 50% reduction in apoptosis after EGF administration. Northern blot analysis and in situ hybridization for SGP-2 mRNA or clusterin gene product also revealed a decreased expression in the obstructed and EGF-treated renal parenchyma.Conclusions. These data suggest that EGF, apart from its known role as a mitogenic substance for renal tubular epithelial cells, is also a critical in vivo renal cell survival factor for the developmentally mature kidney. 相似文献
9.
Pharmacological properties of fluphenazine-mustard, an irreversible calmodulin antagonist 总被引:1,自引:0,他引:1
We describe an improved synthesis and properties of fluphenazine-mustard, a potent phenothiazine having an alkylating chlorethylamine chain in its structure. The drug possesses anticalmodulin activity equivalent to the parent compound, but unlike fluphenazine dihydrochloride, the mustard derivative irreversibly antagonizes the ability of calmodulin to activate cyclic nucleotide phosphodiesterase. This property is partially calcium-dependent and can be overcome by coincubation with excess fluphenazine dihydrochloride. The compound irreversibly inactivated calmodulin when incubated with intact cells and caused single-stranded breakage of DNA. Fluphenazine-mustard possesses potent antiproliferative and cytotoxic properties against malignant cell lines that are likely to be mediated through both of these actions. 相似文献
10.