全文获取类型
收费全文 | 787篇 |
免费 | 47篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 20篇 |
妇产科学 | 14篇 |
基础医学 | 87篇 |
口腔科学 | 128篇 |
临床医学 | 72篇 |
内科学 | 173篇 |
皮肤病学 | 2篇 |
神经病学 | 77篇 |
特种医学 | 13篇 |
外科学 | 40篇 |
综合类 | 1篇 |
预防医学 | 89篇 |
眼科学 | 8篇 |
药学 | 62篇 |
中国医学 | 1篇 |
肿瘤学 | 45篇 |
出版年
2023年 | 6篇 |
2022年 | 19篇 |
2021年 | 23篇 |
2020年 | 18篇 |
2019年 | 20篇 |
2018年 | 28篇 |
2017年 | 22篇 |
2016年 | 34篇 |
2015年 | 18篇 |
2014年 | 34篇 |
2013年 | 46篇 |
2012年 | 75篇 |
2011年 | 78篇 |
2010年 | 37篇 |
2009年 | 37篇 |
2008年 | 60篇 |
2007年 | 57篇 |
2006年 | 36篇 |
2005年 | 28篇 |
2004年 | 33篇 |
2003年 | 27篇 |
2002年 | 41篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1980年 | 5篇 |
1975年 | 1篇 |
排序方式: 共有838条查询结果,搜索用时 12 毫秒
1.
Analysis of the floral transcriptome uncovers new regulators of organ determination and gene families related to flower organ differentiation in Gerbera hybrida (Asteraceae) 下载免费PDF全文
Laitinen RA Immanen J Auvinen P Rudd S Alatalo E Paulin L Ainasoja M Kotilainen M Koskela S Teeri TH Elomaa P 《Genome research》2005,15(4):475-486
Development of composite inflorescences in the plant family Asteraceae has features that cannot be studied in the traditional model plants for flower development. In Gerbera hybrida, inflorescences are composed of morphologically different types of flowers tightly packed into a flower head (capitulum). Individual floral organs such as pappus bristles (sepals) are developmentally specialized, stamens are aborted in marginal flowers, petals and anthers are fused structures, and ovaries are located inferior to other floral organs. These specific features have made gerbera a rewarding target of comparative studies. Here we report the analysis of a gerbera EST database containing 16,994 cDNA sequences. Comparison of the sequences with all plant peptide sequences revealed 1656 unique sequences for gerbera not identified elsewhere within the plant kingdom. Based on the EST database, we constructed a cDNA microarray containing 9000 probes and have utilized it in identification of flower-specific genes and abundantly expressed marker genes for flower scape, pappus, stamen, and petal development. Our analysis revealed several regulatory genes with putative functions in flower-organ development. We were also able to associate a number of abundantly and specifically expressed genes with flower-organ differentiation. Gerbera is an outcrossing species, for which genetic approaches to gene discovery are not readily amenable. However, reverse genetics with the help of gene transfer has been very informative. We demonstrate here the usability of the gerbera microarray as a reliable new tool for identifying novel genes related to specific biological questions and for large-scale gene expression analysis. 相似文献
2.
Dietary carotenoids and risk of lung cancer in a pooled analysis of seven cohort studies. 总被引:5,自引:0,他引:5
Satu M?nnist? Stephanie A Smith-Warner Donna Spiegelman Demetrius Albanes Kristin Anderson Piet A van den Brandt James R Cerhan Graham Colditz Diane Feskanich Jo L Freudenheim Edward Giovannucci R Alexandra Goldbohm Saxon Graham Anthony B Miller Thomas E Rohan Jarmo Virtamo Walter C Willett David J Hunter 《Cancer epidemiology, biomarkers & prevention》2004,13(1):40-48
Intervention trials with supplemental beta-carotene have observed either no effect or a harmful effect on lung cancer risk. Because food composition databases for specific carotenoids have only become available recently, epidemiological evidence relating usual dietary levels of these carotenoids with lung cancer risk is limited. We analyzed the association between lung cancer risk and intakes of specific carotenoids using the primary data from seven cohort studies in North America and Europe. Carotenoid intakes were estimated from dietary questionnaires administered at baseline in each study. We calculated study-specific multivariate relative risks (RRs) and combined these using a random-effects model. The multivariate models included smoking history and other potential risk factors. During follow-up of up to 7-16 years across studies, 3,155 incident lung cancer cases were diagnosed among 399,765 participants. beta-Carotene intake was not associated with lung cancer risk (pooled multivariate RR = 0.98; 95% confidence interval, 0.87-1.11; highest versus lowest quintile). The RRs for alpha-carotene, lutein/zeaxanthin, and lycopene were also close to unity. beta-Cryptoxanthin intake was inversely associated with lung cancer risk (RR = 0.76; 95% confidence interval, 0.67-0.86; highest versus lowest quintile). These results did not change after adjustment for intakes of vitamin C (with or without supplements), folate (with or without supplements), and other carotenoids and multivitamin use. The associations generally were similar among never, past, or current smokers and by histological type. Although smoking is the strongest risk factor for lung cancer, greater intake of foods high in beta-cryptoxanthin, such as citrus fruit, may modestly lower the risk. 相似文献
3.
4.
Johanna Tietvinen Satu Mkel Heini Huhtala Ilkka H. Prsti Tomas Strandin Antti Vaheri Jukka Mustonen 《Viruses》2021,13(6)
Puumala hantavirus (PUUV) causes a hemorrhagic fever with renal syndrome characterized by thrombocytopenia, increased capillary leakage, and acute kidney injury (AKI). As glucosuria at hospital admission predicts the severity of PUUV infection, we explored how plasma glucose concentration associates with disease severity. Plasma glucose values were measured during hospital care in 185 patients with PUUV infection. They were divided into two groups according to maximum plasma glucose concentration: P-Gluc < 7.8 mmol/L (n = 134) and P-Gluc ≥ 7.8 mmol/L (n = 51). The determinants of disease severity were analyzed across groups. Patients with P-Gluc ≥7.8 mmol/L had higher hematocrit (0.46 vs. 0.43; p < 0.001) and lower plasma albumin concentration (24 vs. 29 g/L; p < 0.001) than patients with P-Gluc < 7.8 mmol/L. They presented with higher prevalence of pulmonary infiltrations and pleural effusion in chest radiograph, higher prevalence of shock and greater weight change during hospitalization. Patients with P-Gluc ≥ 7.8 mmol/L were characterized by lower platelet count (50 vs. 66 × 109/L; p = 0.001), more severe AKI (plasma creatinine 272 vs. 151 µmol/L; p = 0.001), and longer hospital treatment (8 vs. 6 days; p < 0.001) than patients with P-Gluc < 7.8 mmol/L. Plasma glucose level is associated with the severity of capillary leakage, thrombocytopenia, inflammation, and AKI in patients with acute PUUV infection. 相似文献
5.
Amina Amadou Heinz Freisling Mazda Jenab Konstantinos K. Tsilidis Antonia Trichopoulou Paolo Boffetta Bethany Van Guelpen Olatz Mokoroa Tom Wilsgaard Frank Kee Ben Schttker Jos M. Ordez-Mena Satu Mnnist Stefan Sderberg Roel C. H. Vermeulen J. Ramn Quirs Linda M. Liao Rashmi Sinha Kari Kuulasmaa Hermann Brenner Isabelle Romieu 《British journal of cancer》2021,124(11):1882
Background We investigated whether associations between prevalent diabetes and cancer risk are pertinent to older adults and whether associations differ across subgroups of age, body weight status or levels of physical activity.Methods We harmonised data from seven prospective cohort studies of older individuals in Europe and the United States participating in the CHANCES consortium. Cox proportional hazard regression was used to estimate the associations of prevalent diabetes with cancer risk (all cancers combined, and for colorectum, prostate and breast). We calculated summary risk estimates across cohorts using pooled analysis and random-effects meta-analysis.Results A total of 667,916 individuals were included with an overall median (P25–P75) age at recruitment of 62.3 (57–67) years. During a median follow-up time of 10.5 years, 114,404 total cancer cases were ascertained. Diabetes was not associated with the risk of all cancers combined (hazard ratio (HR) = 0.94; 95% confidence interval (CI): 0.86–1.04; I2 = 63.3%). Diabetes was positively associated with colorectal cancer risk in men (HR = 1.17; 95% CI: 1.08–1.26; I2 = 0%) and a similar HR in women (1.13; 95% CI: 0.82–1.56; I2 = 46%), but with a confidence interval including the null. Diabetes was inversely associated with prostate cancer risk (HR = 0.81; 95% CI: 0.77–0.85; I2 = 0%), but not with postmenopausal breast cancer (HR = 0.96; 95% CI: 0.89–1.03; I2 = 0%). In exploratory subgroup analyses, diabetes was inversely associated with prostate cancer risk only in men with overweight or obesity.Conclusions Prevalent diabetes was positively associated with colorectal cancer risk and inversely associated with prostate cancer risk in older Europeans and Americans.Subject terms: Risk factors, Cancer epidemiology 相似文献
6.
7.
Hereditary hemochromatosis gene (HFE) mutations C282Y, H63D and S65C in patients with idiopathic dilated cardiomyopathy 总被引:1,自引:0,他引:1
Hannuksela J Leppilampi M Peuhkurinen K Kärkkäinen S Saastamoinen E Heliö T Kaartinen M Nieminen MS Nieminen P Parkkila S 《European journal of heart failure》2005,7(1):103-108
BACKGROUND: Hereditary hemochromatosis (HH), a common autosomal recessive disease, leads to excessive iron accumulation in some organs, including the heart. It is therefore not surprising that cardiomyopathy is one of the most severe complications of HH. The HFE gene defects have been thought to contribute to idiopathic dilated cardiomyopathy (IDCM) in some patients, even though the results of genotype analyses have so far been contradictory. Hence we set out here to evaluate the prevalence and potential role of HFE mutations in patients with IDCM. METHODS: A total of 91 IDCM patients and 102 controls were subjected to HFE mutation analyses, in which C282Y, H63D and S65C mutations were determined for each patient. We also analyzed the impact of the C282Y and H63D mutations on the left ventricular end-diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) functional classes. RESULTS: The prevalences of heterozygosity for the C282Y, H63D and S65C mutations in the IDCM patients were 13.2%, 22.0% and 2.2%, respectively. LVEDD was significantly higher (P=0.037) in those with the C282Y mutation at the end of the follow-up period than in those with no mutation. CONCLUSIONS: Our data showed no significant deviations in C282Y, H63D and S65C mutation frequencies between the IDCM patients and controls, suggesting that these mutations do not increase the risk of IDCM. Heterozygosity for the C282Y mutation may nevertheless be a modifying factor contributing to LV dilatation and remodeling. 相似文献
8.
9.
We report two cases highlighting the diversity of vagal nerve stimulation (VNS)‐related effects on voice and breathing in patients with refractory epilepsy. The patients had both implantation and stimulation‐related side effects, which lasted for several months, impacting on their quality of life. The adverse effects appear to be due to recurrent laryngeal nerve paralysis‐related vocal cord hypofunction and stimulation‐related vocal fold spasms, however, their inter‐relationship is complex. In one of the patients, we were able to utilize the novel programming capabilities of the VNS device to reduce the laryngeal side effects without compromising therapeutic efficacy. [Published with video sequences]. 相似文献
10.
Objectives:To provide an empirical test of the applicability of Locker''s conceptual model of oral health for malocclusion patients, and to suggest alternative models of the effect of malocclusion on well-being.Materials and Methods:Data from a survey of 323 adolescents attending for orthodontic treatment were analyzed to develop a new oral health model for malocclusion patients. Oral health–related quality of life (OHRQoL) was measured using the 14-item Oral Health Impact Profile; malocclusion was measured using the Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN). Using structural equation modeling, the relationship between conceptual domains in Locker''s model was explored and three models of their interrelationship tested for goodness of fit.Results:Fit indexes for Locker''s model indicated that it did not fit the data well. Therefore, a modified model was developed to incorporate additional paths between other levels to better fit the data. The best fit was provided by a model in which the direct effects of malocclusion on pain, discomfort, and handicapping—and the direct effect of pain on disability—were removed. A direct effect of functional limitation on disability was allowed. The modified Oral Health Impact Profile model proved to be a good fit to the data (root mean square error of approximation = 0.069).Conclusion:The pathways identified in Locker''s (1988) conceptual model of oral health may not be appropriate for describing the relationships between OHRQoL constructs in individuals with malocclusion. An alternative model is proposed. 相似文献