全文获取类型
收费全文 | 1050篇 |
免费 | 83篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 53篇 |
妇产科学 | 10篇 |
基础医学 | 107篇 |
口腔科学 | 98篇 |
临床医学 | 152篇 |
内科学 | 243篇 |
皮肤病学 | 5篇 |
神经病学 | 41篇 |
特种医学 | 164篇 |
外科学 | 58篇 |
综合类 | 19篇 |
预防医学 | 82篇 |
眼科学 | 39篇 |
药学 | 55篇 |
肿瘤学 | 34篇 |
出版年
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 15篇 |
2017年 | 9篇 |
2016年 | 4篇 |
2015年 | 12篇 |
2014年 | 14篇 |
2013年 | 26篇 |
2012年 | 27篇 |
2011年 | 28篇 |
2010年 | 49篇 |
2009年 | 50篇 |
2008年 | 27篇 |
2007年 | 43篇 |
2006年 | 38篇 |
2005年 | 38篇 |
2004年 | 24篇 |
2003年 | 32篇 |
2002年 | 34篇 |
2001年 | 32篇 |
2000年 | 24篇 |
1999年 | 31篇 |
1998年 | 53篇 |
1997年 | 52篇 |
1996年 | 52篇 |
1995年 | 42篇 |
1994年 | 46篇 |
1993年 | 30篇 |
1992年 | 22篇 |
1991年 | 24篇 |
1990年 | 23篇 |
1989年 | 33篇 |
1988年 | 30篇 |
1987年 | 17篇 |
1986年 | 26篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1969年 | 5篇 |
1968年 | 3篇 |
1967年 | 6篇 |
排序方式: 共有1170条查询结果,搜索用时 15 毫秒
31.
32.
33.
Nuno?Mendon?aEmail authorView authors OrcID profile Antoneta?Granic John?C.?Mathers Tom?R.?Hill Mario?Siervo Ashley?J.?Adamson Carol?Jagger 《European journal of nutrition》2018,57(8):2713-2722
Purpose
The very old (aged ≥ 85 years), fastest growing age group in most western societies, are at especially high risk of muscle mass and strength loss. The amount, sources and timing of protein intake may play important roles in the aetiology and management of sarcopenia. This study investigated the prevalence and determinants of low protein intake in 722 very old adults participating in the Newcastle 85+ Study.Methods
Protein intake was estimated with 2 × 24-h multiple pass recalls (24 h-MPR) and contribution (%) of food groups to protein intake was calculated. Low protein intake was defined as intake < 0.8 g of protein per adjusted body weight per day. A backward stepwise multivariate linear regression model was used to explore socioeconomic, health and lifestyle predictors of protein intake.Results
Twenty-eight percent (n = 199) of the community-living very old in the Newcastle 85+ Study had low protein intake. Low protein intake was less likely when participants had a higher percent contribution of meat and meat products to total protein intake (OR 0.97, 95% CI 0.95, 1.00) but more likely with a higher percent contribution of cereal and cereal products and non-alcoholic beverages. Morning eating occasions contributed more to total protein intake in the low than in the adequate protein intake group (p < 0.001). Being a woman (p < 0.001), having higher energy intake (p < 0.001) and higher tooth count (p = 0.047) was associated with higher protein intake in adjusted models.Conclusion
This study provides novel evidence on the prevalence of low protein intake, diurnal protein intake patterns and food group contributors to protein intake in the very old.34.
O'Malley CJ; Rasko JE; Basser RL; McGrath KM; Cebon J; Grigg AP; Hopkins W; Cohen B; O'Byrne J; Green MD; Fox RM; Berndt MC; Begley CG 《Blood》1996,88(9):3288-3298
This report describes the effect of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on platelet production and platelet function in humans. Subjects with advanced solid tumors received PEG-rHuMGDF daily for up to 10 days. There was no increase in circulating platelet count at doses of 0.03 or 0.1 microgram/kg/d by day 12 of study. At doses of 0.3 and 1.0 microgram/kg/d there was a threefold median increase (maximum 10-fold) in platelet count by day 16. The platelets produced in vivo in response to PEG-rHuMGDF showed unchanged aggregation and adenosine triphosphate (ATP)-release responses in in vitro assays. Tests included aggregation and release of ATP in response to adenosine diphosphate (ADP) (10, 5, 2.5, and 1.25 mumol/L), collagen (2 micrograms/mL), thrombin-receptor agonist peptide (TRAP, 10 mumol/L) and ristocetin (1.5 mg/mL). Administration of aspirin to an individual with platelet count of 1,771 x 10(3)/L resulted in the typical aspirin-induced ablation of the normal aggregation and ATP-release response to stimulation with arachidonic acid (0.5 mg/mL), collagen, and ADP (2.5 and 1.25 mumol/L). There was no change in the expression of the platelet-surface activation marker CD62P (P-selectin) nor induction of the fibrinogen binding site on glycoprotein IIb/IIIa as reported by the monoclonal antibody, D3GP3. An elevation of reticulated platelets was evident after 3 days of treatment with PEG-rHuMGDF and preceded the increase in circulating platelet count by 5 to 8 days; this reflected the production of new platelets in response to PEG-rHuMGDF. At later time points, the mean platelet volume (MPV) decreased in a manner inversely proportional to the platelet count. Levels of plasma glycocalicin, a measure of platelet turnover, rose 3 days after the initial increase in the peripheral platelet count. The level of plasma glycocalicin was proportional to the total platelet mass, suggesting that platelets generated in response to PEG-rHuMGDF were not more actively destroyed. Thus, the administration of PEG-rHuMGDF, to humans, increased the circulating platelet count and resulted in fully functional platelets, which showed no detectable increase in reactivity nor alteration in activation status. 相似文献
35.
Tessa Timmers Rik Ossenkoppele Denise Visser Hayel Tuncel Emma E Wolters Sander CJ Verfaillie Wiesje M van der Flier Ronald Boellaard Sandeep SV Golla Bart NM van Berckel 《Journal of cerebral blood flow and metabolism》2020,40(12):2464
The aim of this study was to investigate the test–retest (TRT) repeatability of various parametric quantification methods for [18F]Flortaucipir positron emission tomography (PET). We included eight subjects with dementia or mild cognitive impairment due to Alzheimer’s disease and six cognitively normal subjects. All underwent two 130-min dynamic [18F]Flortaucipir PET scans within 3 ± 1 weeks. Data were analyzed using reference region models receptor parametric mapping (RPM), simplified reference tissue method 2 (SRTM2) and reference logan (RLogan), as well as standardized uptake value ratios (SUVr, time intervals 40–60, 80–100 and 110–130 min post-injection) with cerebellar gray matter as reference region. We obtained distribution volume ratio or SUVr, first for all brain regions and then in three tau-specific regions-of-interest (ROIs). TRT repeatability (%) was defined as |retest–test|/(average (test + retest)) × 100. For all methods and across ROIs, TRT repeatability ranged from (median (IQR)) 0.84% (0.68–2.15) to 6.84% (2.99–11.50). TRT repeatability was good for all reference methods used, although semi-quantitative models (i.e. SUVr) performed marginally worse than quantitative models, for instance TRT repeatability of RPM: 1.98% (0.78–3.58) vs. SUVr80–100: 3.05% (1.28–5.52), p < 0.001. Furthermore, for SUVr80–100 and SUVr110–130, with higher average SUVr, more variation was observed. In conclusion, while TRT repeatability was good for all models used, quantitative methods performed slightly better than semi-quantitative methods. 相似文献
36.
37.
38.
CJ Mitchell P Stephany 《Malawi medical journal : the journal of Medical Association of Malawi》2013,25(3):88-89
An outbreak of Tunga Penetrans (Jigger Flea) infestation affecting a number of villages near to a Central Hospital in Malawi is described. Due to the large number of affected individuals, high parasitic load, and extended duration of infection an alternative to the recommended approach of surgical removal of the flea was required. Benzyl benzoate paint and liquid paraffin had been used in local Primary Healthcare settings previously and topical treatment with antiparasitic agents has been advocated in the literature, particularly for severe infestation. Benzyl benzoate and liquid paraffin were applied topically to four adults with numerous jigger flea burrows, and their progress assessed regularly. After completion of 7 days of treatment patients noted that fleas were dislodging spontaneously, and that embedded parasites had not increased in size to the same extent that untreated fleas had in previous infestations. Following confirmation of the viability of its implementation in a resource-poor setting, this treatment regimen has subsequently been adopted by the local branch of the District Health Office for distribution to infected communities. 相似文献
39.
NU Jerath JS Newman & CJ Boes 《Cephalalgia : an international journal of headache》2009,29(10):1028-1033
The aim of this study was to review the life of Mary E. O'Sullivan and to summarize her important contributions to the study of migraine. Mary E. O'Sullivan underwent extensive training to become a neurologist at a time when only 5% of women in America were physicians. She published five papers on migraine. In a 1936 Journal of the American Medical Association article, she described a patient with ergotamine overuse headache and recommended that daily doses of oral ergotamine should be avoided. Three years later she described migraine as a 'complex' syndrome with multiple causes and multiple cures. Mary E. O'Sullivan, an ambitious female headache specialist of the 1930s, was an early advocate of the use of ergotamine to treat migraine, yet she was one of the first to report ergotamine overuse headache. Although her life was short, her research, knowledge and ambition at a time when women had limited opportunities in medicine have left a mark. 相似文献
40.