全文获取类型
收费全文 | 6732篇 |
免费 | 478篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 102篇 |
儿科学 | 166篇 |
妇产科学 | 97篇 |
基础医学 | 789篇 |
口腔科学 | 332篇 |
临床医学 | 518篇 |
内科学 | 1662篇 |
皮肤病学 | 144篇 |
神经病学 | 641篇 |
特种医学 | 245篇 |
外科学 | 968篇 |
综合类 | 17篇 |
预防医学 | 279篇 |
眼科学 | 116篇 |
药学 | 545篇 |
中国医学 | 14篇 |
肿瘤学 | 626篇 |
出版年
2024年 | 5篇 |
2023年 | 62篇 |
2022年 | 142篇 |
2021年 | 319篇 |
2020年 | 174篇 |
2019年 | 245篇 |
2018年 | 276篇 |
2017年 | 198篇 |
2016年 | 263篇 |
2015年 | 294篇 |
2014年 | 333篇 |
2013年 | 424篇 |
2012年 | 569篇 |
2011年 | 559篇 |
2010年 | 305篇 |
2009年 | 261篇 |
2008年 | 435篇 |
2007年 | 410篇 |
2006年 | 408篇 |
2005年 | 359篇 |
2004年 | 328篇 |
2003年 | 223篇 |
2002年 | 214篇 |
2001年 | 32篇 |
2000年 | 24篇 |
1999年 | 36篇 |
1998年 | 35篇 |
1997年 | 27篇 |
1996年 | 18篇 |
1995年 | 24篇 |
1994年 | 19篇 |
1993年 | 16篇 |
1992年 | 23篇 |
1991年 | 18篇 |
1990年 | 12篇 |
1989年 | 22篇 |
1988年 | 20篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 14篇 |
1984年 | 13篇 |
1983年 | 15篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1975年 | 6篇 |
1974年 | 3篇 |
排序方式: 共有7261条查询结果,搜索用时 609 毫秒
51.
Adele Romano Marzia Friuli Laura Del Coco Serena Longo Daniele Vergara Piero Del Boccio Silvia Valentinuzzi Ilaria Cicalini Francesco P. Fanizzi Silvana Gaetani Anna M. Giudetti 《Nutrients》2021,13(2)
Oleoylethanolamide (OEA) is a naturally occurring bioactive lipid belonging to the family of N-acylethanolamides. A variety of beneficial effects have been attributed to OEA, although the greater interest is due to its potential role in the treatment of obesity, fatty liver, and eating-related disorders. To better clarify the mechanism of the antiadipogenic effect of OEA in the liver, using a lipidomic study performed by 1H-NMR, LC-MS/MS and thin-layer chromatography analyses we evaluated the whole lipid composition of rat liver, following a two-week daily treatment of OEA (10 mg kg−1 i.p.). We found that OEA induced a significant reduction in hepatic triacylglycerol (TAG) content and significant changes in sphingolipid composition and ceramidase activity. We associated the antiadipogenic effect of OEA to decreased activity and expression of key enzymes involved in fatty acid and TAG syntheses, such as acetyl-CoA carboxylase, fatty acid synthase, diacylglycerol acyltransferase, and stearoyl-CoA desaturase 1. Moreover, we found that both SREBP-1 and PPARγ protein expression were significantly reduced in the liver of OEA-treated rats. Our findings add significant and important insights into the molecular mechanism of OEA on hepatic adipogenesis, and suggest a possible link between the OEA-induced changes in sphingolipid metabolism and suppression of hepatic TAG level. 相似文献
52.
Calogera Pisano Daniele Polisano Carmela Rita Balistreri Claudia Altieri Paolo Nardi Fabio Bertoldo Daniele Trombetti Laura Asta Maria Sabrina Ferrante Dario Buioni Calogero Foti Giovanni Ruvolo 《Nutrients》2021,13(2)
Frailty is the major expression of accelerated aging and describes a decreased resistance to stressors, and consequently an increased vulnerability to additional diseases in elderly people. The vascular aging related to frail phenotype reflects the high susceptibility for cardiovascular diseases and negative postoperative outcomes after cardiac surgery. Sarcopenia can be considered a biological substrate of physical frailty. Malnutrition and physical inactivity play a key role in the pathogenesis of sarcopenia. We searched on Medline (PubMed) and Scopus for relevant literature published over the last 10 years and analyzed the strong correlation between frailty, sarcopenia and cardiovascular diseases in elderly patient. In our opinion, a right food intake and moderate intensity resistance exercise are mandatory in order to better prepare patients undergoing cardiac operation. 相似文献
53.
Yasmin Amaral Leila Silva Fernanda Soares Daniele Marano Sylvia Nehab Andrea Abranches Ana Carolina Costa Maria Elisabeth Moreira 《Nutrients》2021,13(5)
Background: To evaluate the potential factors associated with the nutritional composition of human milk of puerperal women. Methods: cross-sectional study, conducted between March 2016 and August 2017, with 107 women, selected in a Tertiary Health Care Tertiary Health Facility of the Unified Health System (SUS) in the Municipality of Rio de Janeiro. Data were collected two months after delivery. The dependent variable of the study was the nutritional composition of human milk. We divided the independent variables into hierarchical levels: distal (age, schooling, parity and pregestational nutritional status), intermediate (number of prenatal visits and gestational weight gain) and proximal (alcohol consumption, smoking, diabetes mellitus and hypertension). For data analysis, we applied the multiple linear regression, centered on the hierarchical model. Only the variables associated with the nutritional composition of breast milk remained in the final model at a 5% level of significance. Results: The nutritional composition of human milk yielded by women with pregestational overweight, smokers and hypertensive had higher amounts of lipids and energy. Conversely, women with gestational weight gain below the recommended had lower amounts of these components. Conclusion: The evaluation of factors associated with the nutritional composition of human milk is extremely important to assist post-partum care practices. In this study, we observed that lipid and energy contents were associated to pregestational nutritional status, gestational weight gain, smoking and hypertension. 相似文献
54.
Carlo Giulioni Valentina Maurizi Simone Scarcella Manuel Di Biase Valerio Iacovelli Andrea Benedetto Galosi Daniele Castellani 《Andrologia》2021,53(11):e14215
Our purpose was to review and analyse the impact of pyrethroids and organophosphates exposure on human semen parameters. A comprehensive literature search was performed through MEDLINE via PubMed, Scopus and Webscience. Only cohort studies examining semen parameters in workers or general populations exposed to pyrethroids or organophosphates were included. Ejaculate volume, sperm count, concentration, motility, viability, normal morphology and seminal pH alterations were pooled using the Cochran–Mantel–Haenszel Method with the random effect model and expressed as weighted mean difference, risk ratios, 95% confidence intervals and p-values. Seven cross-sectional studies regarding pyrethroids were included. Four of them were eligible for meta-analysis. The only parameter affected by pyrethroid exposure was normal sperm morphology (WMD-7,61%, 95%CI –11,92 to −3,30;p = 0,0,005). Nine studies were selected to evaluate the impact of organophosphates on semen parameters with six of them eligible for meta-analysis. A significant reduction was detected for the following: ejaculate volume (WMD −0,47ml, 95%CI −0,69 to −0,25; p < 0,0001), sperm count (WMD-40,03, 95%CI −66,81 to −13,25;p = 0,003), concentration (WMD-13,69 x10⁶/mL, 95%CI −23, 27 to-4,12;p = 0,005) and motility (WMD −5,70%, 95%CI −12,89 to 1,50;p = 0,12). Despite the increase in sperm abnormality, it has been shown that pyrethroids are unrelated to reduced sperm quality. However, the negative association of organophosphates with spermatogenesis is noteworthy. 相似文献
55.
Michael Indermaur Daniele Casari Tatiana Kochetkova Cinzia Peruzzi Elizabeth Zimmermann Frank Rauch Bettina Willie Johann Michler Jakob Schwiedrzik Philippe Zysset 《Journal of bone and mineral research》2021,36(7):1364-1375
Osteogenesis imperfecta (OI) is an inheritable, genetic, and collagen-related disorder leading to an increase in bone fragility, but the origin of its “brittle behavior” is unclear. Because of its complex hierarchical structure, bone behaves differently at various length scales. This study aims to compare mechanical properties of human OI bone with healthy control bone at the extracellular matrix (ECM) level and to quantify the influence of the degree of mineralization. Degree of mineralization and mechanical properties were analyzed under dry conditions in 12 fixed and embedded transiliac crest biopsies (control n = 6, OI type I n = 3, OI type IV n = 2, and OI type III n = 1). Mean degree of mineralization was measured by microcomputed tomography at the biopsy level and the mineral-to-matrix ratio was assessed by Raman spectroscopy at the ECM level. Both methods revealed that the degree of mineralization is higher for OI bone compared with healthy control. Micropillar compression is a novel technique for quantifying post-yield properties of bone at the ECM level. Micropillars (d = 5 μm, h = 10 μm) were fabricated using focused ion beam milling and quasi-statically compressed to capture key post-yield properties such as ultimate strength. The qualitative inspection of the stress–strain curves showed that both OI and healthy control bone have a ductile response at the ECM level. The quantitative results showed that compressive strength is not reduced in OI bone and is increasing with OI severity. Nanoindentation measurements revealed that OI bone tends to have a higher Young's modulus, hardness, and dissipated energy compared with healthy bone. Micropillar strength and indentation modulus increased linearly and significantly (p < .0001) with mineral-to-matrix ratio. In conclusion, this study indicates that compressive mechanical properties of dry OI bone at the iliac crest are not inferior to healthy control at the ECM level and increase with mineralization. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). 相似文献
56.
Mosaicism of a novel variant in the ANKRD11 gene in a child with a mild KBG phenotype: A case report
57.
Patrick S. Powell Karen Pazol Lisa D. Wiggins Julie L. Daniels Gabriel S. Dichter Chyrise B. Bradley Rebecca Pretzel Joy Kloetzer Charmaine McKenzie Alexys Scott Britney Robinson Amy S. Sims Eric P. Kasten M. Daniele Fallin Susan E. Levy Patricia M. Dietz Mary E. Cogswell 《MMWR. Morbidity and mortality weekly report》2021,70(17):605
58.
Alice Rosi Pedro Mena Fabio Castello Daniele Del Rio 《International journal of food sciences and nutrition》2021,72(1):70-81
AbstractInformation on children’s diet including bioactive compounds is quite scarce. This observational study investigated the composition of the diet of children living in Parma (Italy; n?=?172, 8–10?years) using 3-day food records completed in winter and spring. Mean daily intakes of food groups, energy and nutrients were obtained using the national food database, while (poly)phenol contents were estimated from Phenol-Explorer or by specific literature searches. Food consumption, energy and nutrient intakes decreased in spring and were partially in line with national data. Adherence to the nutritional recommendations was not satisfied for the majority of nutrients. Main contributors to the phenolic intake were flavonoids (flavan-3-ols) and phenolic acids (hydroxycinnamic acids), while main dietary sources were fruit, chocolate-based products, vegetables, and tea & coffee (decaffeinated). This study provided the first comprehensive analysis of the nutritional composition of children’s diet. Future research should look at the health implications of dietary choices in children. 相似文献
59.
Zoledronic acid-related angiogenesis modifications and survival in advanced breast cancer patients. 总被引:5,自引:0,他引:5
Bruno Vincenzi Daniele Santini Giordano Dicuonzo Fabrizio Battistoni Michele Gavasci Annalisa La Cesa Claudia Grilli Vladimir Virzì Simona Gasparro Laura Rocci Giuseppe Tonini 《Journal of interferon & cytokine research》2005,25(3):144-151
The proven antiangiogenic activity of zoledronic acid, a third-generation bisphosphonate widely used in bone metastatic cancer patients, led us to investigate if the vascular endothelial growth factor (VEGF)-related zoledronic acid modifications are correlated with survival advantages in advanced breast cancer patients. Forty-two consecutive breast cancer patients with scintigraphic and radiographic evidence of bone metastases were treated with a single infusion of 4 mg zoledronic acid before anticancer chemotherapy. The patients were prospectively evaluated for circulating levels of VEGF and interferon-gamma (IFN-gamma) just before and at 1, 2, 7, and 21 days after zoledronic acid infusion. Afterward, clinical outcome was prospectively monitored. The basal serum VEGF median levels were significantly decreased at each time point, but the major reduction was recorded 21 days after the infusion. In particular, 25 patients of 42 (59.5%) experienced a reduction of at least 25% in the VEGF circulating levels. In contrast, no statistically significant modifications of the IFN-gamma serum levels were recorded. We stratified patients on the basis of this VEGF reduction 21 days after the infusion. No differences in patient features were recorded between those with or without the VEGF reduction. The analysis of survival showed that patients with a reduction in the VEGF circulating levels had a longer time to first skeletal-related event (p = 0.0002), time to bone progression disease (p = 0.0024), and time to performance status worsening (p = 0.0352) than those without the VEGF reduction. No statistically significant differences were recorded in terms of overall survival and time to visceral progression. This study confirms that zoledronic acid could have an in vivo antiangiogenic property and that the VEGF modifications may represent a surrogate marker able to predict time to first skeletal-related event, time to bone progression disease, and time to worsening of performance status. 相似文献
60.