全文获取类型
收费全文 | 15363篇 |
免费 | 1435篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 102篇 |
儿科学 | 535篇 |
妇产科学 | 596篇 |
基础医学 | 2037篇 |
口腔科学 | 208篇 |
临床医学 | 1973篇 |
内科学 | 3103篇 |
皮肤病学 | 170篇 |
神经病学 | 1168篇 |
特种医学 | 376篇 |
外科学 | 1939篇 |
综合类 | 316篇 |
一般理论 | 25篇 |
预防医学 | 1985篇 |
眼科学 | 264篇 |
药学 | 1060篇 |
中国医学 | 13篇 |
肿瘤学 | 967篇 |
出版年
2023年 | 130篇 |
2022年 | 121篇 |
2021年 | 329篇 |
2020年 | 280篇 |
2019年 | 358篇 |
2018年 | 406篇 |
2017年 | 292篇 |
2016年 | 366篇 |
2015年 | 360篇 |
2014年 | 478篇 |
2013年 | 667篇 |
2012年 | 1017篇 |
2011年 | 1111篇 |
2010年 | 587篇 |
2009年 | 456篇 |
2008年 | 901篇 |
2007年 | 921篇 |
2006年 | 886篇 |
2005年 | 859篇 |
2004年 | 698篇 |
2003年 | 693篇 |
2002年 | 620篇 |
2001年 | 297篇 |
2000年 | 275篇 |
1999年 | 256篇 |
1998年 | 139篇 |
1997年 | 120篇 |
1996年 | 117篇 |
1995年 | 104篇 |
1994年 | 118篇 |
1993年 | 82篇 |
1992年 | 170篇 |
1991年 | 131篇 |
1990年 | 158篇 |
1989年 | 172篇 |
1988年 | 127篇 |
1987年 | 156篇 |
1986年 | 109篇 |
1985年 | 111篇 |
1984年 | 91篇 |
1983年 | 107篇 |
1982年 | 70篇 |
1981年 | 79篇 |
1979年 | 108篇 |
1978年 | 86篇 |
1977年 | 70篇 |
1974年 | 80篇 |
1973年 | 75篇 |
1972年 | 82篇 |
1971年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Marike Gabrielson Mattias Hammarström Magnus Bäcklund Jenny Bergqvist Kristina Lång Ann H Rosendahl Signe Borgquist Roxanna Hellgren Kamila Czene Per Hall 《International journal of cancer. Journal international du cancer》2023,152(11):2362-2372
Tamoxifen prevents recurrence of breast cancer and is suggested for preventive risk-reducing therapy. Tamoxifen reduces mammographic density, a proxy for therapy response, but little is known about its effects in remodelling normal breast tissue. Our study, a substudy within the double-blinded dose-determination trial KARISMA, investigated tamoxifen-specific changes in breast tissue composition and histological markers in healthy women. We included 83 healthy women randomised to 6 months daily intake of 20, 10, 5, 2.5, 1 mg of tamoxifen or placebo. The groups were combined to “no dose” (0-1 mg), “low-dose” (2.5-5 mg) or “high-dose” (10-20 mg) of tamoxifen. Ultrasound-guided biopsies were collected before and after tamoxifen exposure. In each biopsy, epithelial, stromal and adipose tissues was quantified, and expression of epithelial and stromal Ki67, oestrogen receptor (ER) and progesterone receptor (PR) analysed. Mammographic density using STRATUS was measured at baseline and end-of-tamoxifen-exposure. We found that different doses of tamoxifen reduced mammographic density and glandular-epithelial area in premenopausal women and associated with reduced epithelium and increased adipose tissue. High-dose tamoxifen also decreased epithelial ER and PR expressions in premenopausal women. Premenopausal women with the greatest reduction in proliferation also had the greatest epithelial reduction. In postmenopausal women, high-dose tamoxifen decreased the epithelial area with no measurable density decrease. Tamoxifen at both low and high doses influences breast tissue composition and expression of histological markers in the normal breast. Our findings connect epithelial proliferation with tissue remodelling in premenopausal women and provide novel insights to understanding biological mechanisms of primary prevention with tamoxifen. 相似文献
2.
Caroline Williamsson Jenny Rystedt Bodil Andersson 《HPB : the official journal of the International Hepato Pancreato Biliary Association》2021,23(6):847-853
BackgroundLittle is known of possible gender differences in treatment of periampullary tumours and outcome after pancreatoduodenectomy (PD), and the aim of this study was therefore to investigate any variances from national multicentre perspective.MethodsData from the Swedish National Registry for Pancreatic and Periampullary Cancer for all patients diagnosed with a periampullary tumour from 2012 throughout 2017 was collected. The material was analysed in two groups, men and women, for palliative treatment and curative intended resection.ResultsA total of 5677 patients were included, 2906 (51%) men and 2771 (49%) women. Women were older than men, 72 (65–78) years vs. 70 (64–76), p < 0.001. A lesser proportion of women were planned for resection (1131 (41%) vs. 1288 (44%), p = 0.008), but after adjusting for age and tumour location no difference was seen. Postoperative morbidity was equal, but women had significantly better long-term survival than men. The survival was equal for palliative men and women.ConclusionNo gender bias could be established when analysing treatment for periampullary tumours in Sweden, even though less women were offered surgery. Data suggest that even though women were older they tolerate surgery well and hence offering PD at a higher age for women could be suggested. 相似文献
3.
Conall T. Morgan Brigitte Mueller Varsha Thakur Vitor Guerra Callaghan Jull Luc Mertens Mark Friedberg Fraser Golding Mike Seed Steven E.S. Miner Edgar T. Jaeggi Cedric Manlhiot Lynne E. Nield 《The Canadian journal of cardiology》2019,35(4):453-461
Background
The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.Methods
A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.Results
Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.Conclusions
In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler. 相似文献4.
5.
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
6.
7.
8.
Mithun Sattur Clayton Korson Fraser Henderson Stephen Kalhorn 《The American journal of emergency medicine》2019,37(5):1005.e1-1005.e2
Occipital spur is an abnormal bony outgrowth of the external occipital protuberance (EOP). We describe an interesting and previously unreported case of fracture of an occipital spur following trauma. Our 20-year-old male patient was treated in the emergency department (ED) and discharged home without complication. Neurosurgical consultation was obtained but is not requisite for these injuries. Greater awareness of this unique presentation may help to expedite future emergency department treatment. 相似文献
9.
10.