全文获取类型
收费全文 | 15909篇 |
免费 | 1510篇 |
国内免费 | 301篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 1209篇 |
妇产科学 | 162篇 |
基础医学 | 418篇 |
口腔科学 | 127篇 |
临床医学 | 1753篇 |
内科学 | 1439篇 |
皮肤病学 | 54篇 |
神经病学 | 207篇 |
特种医学 | 255篇 |
外国民族医学 | 2篇 |
外科学 | 1386篇 |
综合类 | 1955篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 6588篇 |
眼科学 | 28篇 |
药学 | 1341篇 |
11篇 | |
中国医学 | 285篇 |
肿瘤学 | 481篇 |
出版年
2024年 | 18篇 |
2023年 | 294篇 |
2022年 | 959篇 |
2021年 | 1072篇 |
2020年 | 726篇 |
2019年 | 641篇 |
2018年 | 606篇 |
2017年 | 682篇 |
2016年 | 699篇 |
2015年 | 730篇 |
2014年 | 983篇 |
2013年 | 1256篇 |
2012年 | 887篇 |
2011年 | 980篇 |
2010年 | 769篇 |
2009年 | 707篇 |
2008年 | 632篇 |
2007年 | 692篇 |
2006年 | 569篇 |
2005年 | 526篇 |
2004年 | 429篇 |
2003年 | 369篇 |
2002年 | 303篇 |
2001年 | 305篇 |
2000年 | 275篇 |
1999年 | 211篇 |
1998年 | 152篇 |
1997年 | 134篇 |
1996年 | 136篇 |
1995年 | 100篇 |
1994年 | 86篇 |
1993年 | 99篇 |
1992年 | 66篇 |
1991年 | 74篇 |
1990年 | 49篇 |
1989年 | 61篇 |
1988年 | 45篇 |
1987年 | 50篇 |
1986年 | 30篇 |
1985年 | 62篇 |
1984年 | 36篇 |
1983年 | 26篇 |
1982年 | 47篇 |
1981年 | 24篇 |
1980年 | 27篇 |
1979年 | 16篇 |
1978年 | 23篇 |
1977年 | 16篇 |
1976年 | 9篇 |
1975年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
795例肠外营养支持的回顾性分析 总被引:2,自引:0,他引:2
目的:对795例患者的肠外营养支持进行回顾性分析.方法:对行肠外营养支持的399例患者进行治疗前后淋巴细胞计数、血浆白蛋白和血浆锌离子浓度等营养学指标的比较,并选择行肠外营养的患者198例与行单一静脉营养的患者198例进行营养学指标的比较,同时比较不良反应和依从性.另选择25例有单一静脉营养史患者25例,分为足量组13例和低氮组12例,分别按照1.0~1.5和0.6 g·kg-1·d-1逐渐在3 d内递增到1.0~1.5 g·kg-1·d-1给予氨基酸,其余营养支持相同, 进行营养学指标的比较.结果:与治疗前比较,行肠外营养支持后患者的白蛋白、淋巴细胞计数、锌离子浓度等均显著增加(P<0.05).与单一静脉营养相比较,行肠外营养患者的白蛋白、淋巴细胞计数、锌离子浓度等也均显著增加(P<0.05),同时不良反应和依从性较好.足量组与低氮组比较,白蛋白值显著增加,而淋巴细胞计数、锌离子浓度无显著性差异.结论:肠外营养支持可以显著改善营养不良. 相似文献
52.
A realist qualitative study to explore how low‐income pregnant women use Healthy Start food vouchers
Heather Ohly Nicola Crossland Fiona Dykes Nicola Lowe Victoria Hall Moran 《Maternal & child nutrition》2019,15(1)
Healthy Start is the UK government's food voucher programme for low‐income pregnant women and young children. It was introduced in 2006, but the impact of the programme on nutritional outcomes remains understudied. This study sought to explore potential outcomes of the Healthy Start programme (including intended and unintended outcomes) and develop explanations for how and why these outcomes might occur. A realist review preceded this study, in which programme theories were developed and tested using existing evidence. This qualitative study aimed to further refine and consolidate the programme theories from the realist review while remaining open to new and emerging theories (or hypotheses) about how low‐income pregnant women use Healthy Start vouchers. Semistructured interviews were conducted with 11 low‐income women from North West England, who received Healthy Start vouchers during pregnancy. A realist logic of analysis was applied to generate clear and transparent linkages between outcomes and explanations. The findings suggested that some women used the vouchers to improve their diets during pregnancy (intended outcome), whereas some women were diverted towards alternative or unintended outcomes. Women's circumstances, values, beliefs, and motivations influenced how they perceived and responded to the vouchers. This paper presents four evidence‐based programme theories to explain four contrasting (and potentially overlapping) outcomes: dietary improvements (theory refined from review), shared benefits (new theory), financial assistance (theory refined from review), and stockpiling formula (new theory). It considers how the Healthy Start programme could be improved, to increase the possibilities for low‐income women to experience the intended outcome of dietary improvements. 相似文献
53.
This paper introduces a novel survey instrument to identify distinct components of nutrition knowledge and test for links between knowledge and dietary choices in Southern Malawi. Our first aim is to distinguish respondents' familiarity with recommended behaviours, such as when to start breastfeeding or introduce solid foods, from respondents' factual knowledge about mechanisms, such as whether biscuits or papaya and orange fruit or orange Fanta contribute more to future health. We find knowledge of nutrition behaviours to be strongly associated with more schooling, older age, and being female, whereas knowledge of mechanisms is associated only with training and employment as a health professional. We then test whether this expanded definition of nutrition knowledge is associated with dietary intake when controlling for other factors and find no significant links in these data. Results point to the need for knowledge surveys and public health behaviour‐change campaigns to address the kinds of information that might have the most influence on actual behaviour, potentially including the mechanisms involved in food composition, food safety, and disease transmission. 相似文献
54.
目的探讨全肠外营养诱导新生乳猪线粒体应激介导的肝细胞凋亡的作用机制。方法以肠内营养乳猪作为对照,建立全肠外营养新生乳猪实验动物模型,喂养7d后获取肝脏组织,分离原代肝细胞,部分肝组织应用琼脂糖凝胶电泳检测肝细胞DNA凋亡条带,通过凋亡蛋白活性测定、免疫组织化学、Western blot印迹法等检测全肠外营养诱导肝细胞发生凋亡的蛋白表达。结果全肠外营养组乳猪肝细胞活率为(49±21)%,明显低于肠内营养组的(88±14)%(P〈0.05)。全肠外营养乳猪肝组织DNA电泳呈现典型梯形凋亡条带,细胞凋亡ELISA检测发现细胞凋亡定量高达对照组的2.6倍,半胱天冬氨酸蛋白酶(caspase)-3活性也明显升高,与肠内营养相比增高9.9倍,但ATP酶活性下降了24%。Westernblot显示全肠外营养组肝组织中相关凋亡蛋白酶PARP、caspase-9和-7蛋白酶原被活化,Bcl-2蛋白表达量下调,Bax蛋白量表达上调;同时线粒体内细胞色素C释放至胞浆内,使胞浆内细胞色素C表达水平升高。免疫组织化学也显示全肠外营养组Bax表达上调。结论全肠外营养可以损伤肝组织,并通过线粒体应激信号传导通路诱导肝细胞凋亡。 相似文献
55.
目的:探讨肝衰竭病人营养支持中实施夜间营养护理干预的效果。方法:选取2019年3月—2020年7月在我院治疗的82例肝衰竭病人为研究对象,通过随机数字表法分为日间组(41例)及夜间组(41例)。日间组在内科综合治疗基础上给予日间营养干预,夜间组在日间组的基础上加强夜间营养护理。比较两组相关营养指标、Child-Pugh评分、营养风险筛查表2002(NRS-2002)评分、生活质量变化情况。结果:经夜间营养护理干预后,夜间组血清总蛋白(TP)、白蛋白(ALB)、转铁蛋白(TF)、前白蛋白(PA)水平高于日间组,差异均有统计学意义(P<0.001);干预2周、4周后夜间组Child-Pugh评分均低于日间组,NRS-2002评分明显低于日间组,差异均有统计学意义(P<0.001);夜间组营养护理干预4周后生活质量GQOL-74量表评分高于日间组,差异有统计学意义(P<0.001)。结论:肝衰竭病人住院期间加强实施夜间营养护理干预,可明显改善病人营养状况,降低营养不良发生风险,改善病人生活质量。 相似文献
56.
早产儿肠内营养新概念 总被引:12,自引:0,他引:12
早产儿的营养支持是复杂和具有挑战性的系统工程。在早产儿肠内营养的实施过程中,应基于其生理特点,不仅从营养学而且从促进胃肠功能成熟的角度进行喂养,正确选择适合早产儿的喂养方法和乳类;不仅要关注营养对早期生长发育和对疾病反应方面的影响,更重要的是他们的远期健康。根据目前循证医学研究的证据来更新观念,走出误区,对于指导临床实践,改善早产儿的预后十分必要。 相似文献
57.
目的:观察胃癌患者围手术期使用中药大黄和肠内营养对TNF-α水平的影响。方法:将56名胃癌围手术期患者随机分为对照组(A组)20例;肠内营养组(B组)21例;大黄加肠内营养组(C组)15例。A组术后常规补液的同时实施肠外营养支持;B组术后常规补液的同时术后42h始给予肠内营养能全力,一直持续到术后第8天;C组病人术前1天应用大黄10g,术后18、42h分2次各5g。B组和C组术后数日内每天的液体量、热量及氮量不足部分均由肠外途径予以补足。所有研究对象分别于手术前1天、手术后第1、3、7天检测外周血肿瘤坏死因子(Tumor Necrosis Factorα,TNF-α)浓度。结果:各组患者术后均有急性炎性反应的发生,但C组术后第3、7天的TNF-α水平较A有显著下降,术后排气、排便时间和肠鸣音的恢复显著提前。术后的营养指标B组、C组患者间无明显差异。结论:胃癌患者围手术期应用大黄可以有效降低外周血TNF-α水平,缓解手术创伤引起的急性炎性反应,促进术后胃肠道功能恢复,有利于实施术后肠内营养支持。 相似文献
58.
Marina Gonzalez-Ramirez Rocio Sanchez-Carrera Angela Cejudo-Lopez Mauricio Lozano-Navarrete Elena Salamero Snchez-Gabriel M. Alfonso Torres-Bengoa Manuel Segura-Balbuena Maria J. Sanchez-Cordero Mercedes Barroso-Vazquez Francisco J. Perez-Barba Ana M. Troncoso M. Carmen Garcia-Parrilla Ana B. Cerezo 《Nutrients》2022,14(10)
Promoting a healthy diet is a relevant strategy for preventing non-communicable diseases. This study aims to evaluate the impact of an innovative tool, the SAlBi educa nutrition app, in primary healthcare dietary counseling to improve dietary profiles as well as adherence to the Mediterranean diet. A multi-center randomized control trial comprising 104 participants was performed. Both control (n = 49) and intervention (n = 55) groups attended four once-weekly sessions focusing on healthy eating habits and physical activity, over one month. As well as attending the meetings, the intervention group used the app, which provides self-monitoring and tailored dietary advice based on the Mediterranean diet model. In a second intervention (one arm trial), the potential of SAlBi educa was evaluated for three months during the COVID-19 pandemic. At 4 weeks, the intervention group had significantly increased their carbohydrate intake (7.7% (95% CI: 0.16 to 15.2)) and decreased their total fat intake (−5.7% (95% CI: −10.4 to −1.15)) compared to the control group. Significant differences were also found for carbohydrates (3.5% (95% CI: −1.0 to 5.8)), total fats (−5.9% (95% CI: −8.9 to −3.0)), fruits and vegetables (266.3 g/day (95% CI: 130.0 to 402.6)), legumes (7.7g/day (95% CI: 0.2 to 15.1)), starchy foods (36.4 g/day (95% CI: 1.1 to 71.7)), red meat (−17.5 g/day (95% CI: −34.0 to −1.1)), and processed meat (−6.6 g/day (95% CI: −13.1 to −0.1)) intakes during the COVID-19 pandemic. SAlBi educa is a useful tool to support nutrition counseling in primary healthcare, including in special situations such as the COVID-19 pandemic. Trial registration: ISRCTN57186362. 相似文献
59.
Kirsten H. Leng Amy L. Yaroch Nadine Budd Nugent Sarah A. Stotz James Krieger 《Nutrients》2022,14(10)
Increased fruit and vegetable (FV) intake is associated with decreased risk of nutrition-related chronic diseases. Sociodemographic disparities in FV intake indicate the need for strategies that promote equitable access to FVs. The United States Department of Agriculture’s Gus Schumacher Nutrition Incentive Program (GusNIP) supports state and local programs that offer nutrition incentives (NIs) that subsidize purchase of FVs for people participating in the Supplemental Nutrition Assistance Program (SNAP). While a growing body of research indicates NIs are effective, the pathways through which GusNIP achieves its results have not been adequately described. We used an equity-focused, participatory process to develop a retrospective Theory of Change (TOC) to address this gap. We reviewed key program documents; conducted a targeted NI literature review; and engaged GusNIP partners, practitioners, and participants through interviews, workshops, and focus groups in TOC development. The resulting TOC describes how GusNIP achieves its long-term outcomes of increased participant FV purchases and intake and food security and community economic benefits. GusNIP provides NIs and promotes their use, helps local food retailers develop the capacity to sell FVs and accept NIs in accessible and welcoming venues, and supports local farmers to supply FVs to food retailers. The TOC is a framework for understanding how GusNIP works and a tool for improving and expanding the program. 相似文献
60.