全文获取类型
收费全文 | 127151篇 |
免费 | 6540篇 |
国内免费 | 191篇 |
专业分类
耳鼻咽喉 | 1960篇 |
儿科学 | 5358篇 |
妇产科学 | 4126篇 |
基础医学 | 17720篇 |
口腔科学 | 3849篇 |
临床医学 | 9235篇 |
内科学 | 24514篇 |
皮肤病学 | 3605篇 |
神经病学 | 9724篇 |
特种医学 | 5246篇 |
外国民族医学 | 32篇 |
外科学 | 20321篇 |
综合类 | 1631篇 |
一般理论 | 34篇 |
预防医学 | 6951篇 |
眼科学 | 3504篇 |
药学 | 8901篇 |
中国医学 | 459篇 |
肿瘤学 | 6712篇 |
出版年
2021年 | 987篇 |
2019年 | 997篇 |
2018年 | 1359篇 |
2017年 | 1090篇 |
2016年 | 1422篇 |
2015年 | 1608篇 |
2014年 | 2100篇 |
2013年 | 3025篇 |
2012年 | 4007篇 |
2011年 | 4207篇 |
2010年 | 2460篇 |
2009年 | 2329篇 |
2008年 | 3878篇 |
2007年 | 4135篇 |
2006年 | 4185篇 |
2005年 | 4222篇 |
2004年 | 4069篇 |
2003年 | 3879篇 |
2002年 | 3828篇 |
2001年 | 7221篇 |
2000年 | 7163篇 |
1999年 | 6022篇 |
1998年 | 1665篇 |
1997年 | 1601篇 |
1996年 | 1356篇 |
1995年 | 1229篇 |
1994年 | 1128篇 |
1993年 | 1141篇 |
1992年 | 3846篇 |
1991年 | 3625篇 |
1990年 | 3619篇 |
1989年 | 3398篇 |
1988年 | 3021篇 |
1987年 | 2920篇 |
1986年 | 2831篇 |
1985年 | 2647篇 |
1984年 | 1964篇 |
1983年 | 1606篇 |
1982年 | 935篇 |
1981年 | 921篇 |
1979年 | 1837篇 |
1978年 | 1367篇 |
1977年 | 1121篇 |
1976年 | 950篇 |
1975年 | 1195篇 |
1974年 | 1227篇 |
1973年 | 1220篇 |
1972年 | 1050篇 |
1971年 | 996篇 |
1970年 | 897篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Iclea Rocha Gama Euclides Marinho Trindade-Filho Suzana Lima Oliveira Nassib Bezerra Bueno Isabelle Tenório Melo Cyro Rego Cabral-Junior Elenita M. Barros Jaqueline A. Galvão Wanessa S. Pereira Raphaela C. Ferreira Bruna R. Domingos Terezinha da Rocha Ataide 《Metabolic brain disease》2015,30(1):93-98
5.
6.
Stephan Koter Tina U. Cohnert Korbinian B. Hindermayr Jörg Lindenmann Maximilian Brückner Wolfgang K. Oswald Georg Werkgartner Doris Wagner 《Journal of vascular surgery》2019,69(4):1227-1232
Objective
Low psoas muscle area is shown to be an indicator for worse postoperative outcome in patients undergoing vascular surgical. Additionally, it has been associated with longer durations of hospital stay in patients with cancer who undergo surgery and subsequently greater health care costs in Europe and the United States. We sought to evaluate this effect on hospital expenditure for patients undergoing vascular repair in a health care system with universal access.Methods
Skeletal muscle mass was assessed on preoperative abdominal computed tomography scans of patients undergoing open aortic aneurysm repair in a retrospective fashion. The skeletal muscle index (SMI) was used to define low muscle mass. Health care costs were obtained for all patients and the relationship between a low SMI and higher costs was explored using linear regression and cross-sectional analysis.Results
We included 156 patients (81.5% male) with a median age of 72 years undergoing elective surgery for infrarenal abdominal aortic aneurysm in this analysis. The median SMI for patients with low skeletal muscle mass was 53.21 cm2/kg and for patients without, 70.07 cm2/kg. Hospital duration of stay was 2 days longer in patients with low skeletal muscle mass as compared with patients with normal (14 days vs 11 days; P = .001), as was duration of intensive care stay (3 days vs 1 day; P = .01). The median overall hospital costs were €10,460 higher for patients with a low SMI as compared with patients with a normal physical constitution (€53,739 [interquartile range, €45,007-€62,471] vs €43,279 [interquartile range, €39,509-€47,049]; P = .001). After confounder adjustment, a low SMI was associated with a 14.68% cost increase in overall hospital costs, for a cost increase of €6521.Conclusions
Low skeletal muscle mass is independently associated with higher hospital as well as intensive care costs in patients undergoing elective aortic aneurysm repair. Strategies to reduce this risk factor are warranted for these patients. 相似文献7.
Jenny U. Johansson Nathaniel S. Woodling Qian Wang Maharshi Panchal Xibin Liang Angel Trueba-Saiz Holden D. Brown Siddhita D. Mhatre Taylor Loui Katrin I. Andreasson 《The Journal of clinical investigation》2015,125(1):350-364
Microglia, the innate immune cells of the CNS, perform critical inflammatory and noninflammatory functions that maintain normal neural function. For example, microglia clear misfolded proteins, elaborate trophic factors, and regulate and terminate toxic inflammation. In Alzheimer’s disease (AD), however, beneficial microglial functions become impaired, accelerating synaptic and neuronal loss. Better understanding of the molecular mechanisms that contribute to microglial dysfunction is an important objective for identifying potential strategies to delay progression to AD. The inflammatory cyclooxygenase/prostaglandin E2 (COX/PGE2) pathway has been implicated in preclinical AD development, both in human epidemiology studies and in transgenic rodent models of AD. Here, we evaluated murine models that recapitulate microglial responses to Aβ peptides and determined that microglia-specific deletion of the gene encoding the PGE2 receptor EP2 restores microglial chemotaxis and Aβ clearance, suppresses toxic inflammation, increases cytoprotective insulin-like growth factor 1 (IGF1) signaling, and prevents synaptic injury and memory deficits. Our findings indicate that EP2 signaling suppresses beneficial microglia functions that falter during AD development and suggest that inhibition of the COX/PGE2/EP2 immune pathway has potential as a strategy to restore healthy microglial function and prevent progression to AD. 相似文献
8.
Increased arterial stiffness in young normotensive patients with Turner syndrome: associations with vascular biomarkers 下载免费PDF全文
9.
Adilson Cunha Ferreira Edward Araujo Júnior Wellington P. Martins João Francisco Jordão Antônio Hélio Oliani Simon E. Meagher 《The journal of maternal-fetal & neonatal medicine》2015,28(14):1706-1710
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality. 相似文献
10.
Joseane Balan Da Silva Gleison Daion Piovezana Bossolani Camila Piva Greicy Brisa Malaquias Dias Jancarlo Gomes Ferreira Diogo Francisco Rossoni 《International journal of environmental health research》2016,26(5-6):578-588
The spatial distribution of enteroparasitosis in an indigenous village from Paraná was evaluated to identify areas of risk for these infections. A cross-sectional study (from November 2010 to June 2011) was performed using Three Faecal Test® and Kato &; Katz method and a questionnaire on housing and hygiene conditions was administered. Local geostatistical analyses were performed to determine the spatial distribution of intestinal parasitic infections. The overall prevalence of enteroparasites was 67.2?% (457/680), and the most prevalent taxa were Ascaris lumbricoides (48.8?%) and Trichuris trichiura (44.7?%). The prevalence of heavy infection by soil-transmitted helminths was 3.6?% and the families lived in houses with an average of 5.1 residents and < 2 bedrooms per household. The average number of species per individual present spatial heterogeneity with the highest values (≥0.8) in areas with high clustering of residences. The visualization of the spatial distribution of intestinal parasites in this indigenous village is an important contribution to determining health risk areas and planning decisions and services. 相似文献