全文获取类型
收费全文 | 367篇 |
免费 | 24篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 13篇 |
妇产科学 | 5篇 |
基础医学 | 53篇 |
口腔科学 | 21篇 |
临床医学 | 35篇 |
内科学 | 84篇 |
皮肤病学 | 8篇 |
神经病学 | 7篇 |
特种医学 | 53篇 |
外科学 | 13篇 |
综合类 | 13篇 |
预防医学 | 43篇 |
眼科学 | 3篇 |
药学 | 22篇 |
肿瘤学 | 27篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 13篇 |
2012年 | 8篇 |
2011年 | 5篇 |
2010年 | 17篇 |
2009年 | 16篇 |
2008年 | 11篇 |
2007年 | 24篇 |
2006年 | 22篇 |
2005年 | 9篇 |
2004年 | 15篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 11篇 |
1998年 | 15篇 |
1997年 | 13篇 |
1996年 | 18篇 |
1995年 | 12篇 |
1994年 | 16篇 |
1993年 | 11篇 |
1992年 | 3篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有409条查询结果,搜索用时 390 毫秒
71.
72.
Duffy SW Nagtegaal ID Astley SM Gillan MG McGee MA Boggis CR Wilson M Beetles UM Griffiths MA Jain AK Johnson J Roberts R Deans H Duncan KA Iyengar G Griffiths PM Warwick J Cuzick J Gilbert FJ 《Breast cancer research : BCR》2008,10(4):R64-7
Introduction
Mammographic density is known to be a strong risk factor for breast cancer. A particularly strong association with risk has been observed when density is measured using interactive threshold software. This, however, is a labour-intensive process for large-scale studies.Methods
Our aim was to determine the performance of visually assessed percent breast density as an indicator of breast cancer risk. We compared the effect on risk of density as measured with the mediolateral oblique view only versus that estimated as the average density from the mediolateral oblique view and the craniocaudal view. Density was assessed using a visual analogue scale in 10,048 screening mammograms, including 311 breast cancer cases diagnosed at that screening episode or within the following 6 years.Results
Where only the mediolateral oblique view was available, there was a modest effect of breast density on risk with an odds ratio for the 76% to 100% density relative to 0% to 25% of 1.51 (95% confidence interval 0.71 to 3.18). When two views were available, there was a considerably stronger association, with the corresponding odds ratio being 6.77 (95% confidence interval 2.75 to 16.67).Conclusion
This indicates that a substantial amount of information on risk from percentage breast density is contained in the second view. It also suggests that visually assessed breast density has predictive potential for breast cancer risk comparable to that of density measured using the interactive threshold software when two views are available. This observation needs to be confirmed by studies applying the different measurement methods to the same individuals. 相似文献73.
Gilbert FJ Astley SM Boggis CR McGee MA Griffiths PM Duffy SW Agbaje OF Gillan MG Wilson M Jain AK Barr N Beetles UM Griffiths MA Johnson J Roberts RM Deans HE Duncan KA Iyengar G 《Breast cancer research : BCR》2008,10(4):R72-8
Introduction
The purpose of the present study was to investigate the effect of computer-aided detection (CAD) prompts on reader behaviour in a large sample of breast screening mammograms by analysing the relationship of the presence and size of prompts to the recall decision.Methods
Local research ethics committee approval was obtained; informed consent was not required. Mammograms were obtained from women attending routine mammography at two breast screening centres in 1996. Films, previously double read, were re-read by a different reader using CAD. The study material included 315 cancer cases comprising all screen-detected cancer cases, all subsequent interval cancers and 861 normal cases randomly selected from 10,267 cases. Ground truth data were used to assess the efficacy of CAD prompting. Associations between prompt attributes and tumour features or reader recall decisions were assessed by chi-squared tests.Results
There was a highly significant relationship between prompting and a decision to recall for cancer cases and for a random sample of normal cases (P < 0.001). Sixty-four per cent of all cases contained at least one CAD prompt. In cancer cases, larger prompts were more likely to be recalled (P = 0.02) for masses but there was no such association for calcifications (P = 0.9). In a random sample of 861 normal cases, larger prompts were more likely to be recalled (P = 0.02) for both mass and calcification prompts. Significant associations were observed with prompting and breast density (p = 0.009) for cancer cases but not for normal cases (P = 0.05).Conclusions
For both normal cases and cancer cases, prompted mammograms were more likely to be recalled and the prompt size was also associated with a recall decision. 相似文献74.
Ward H Chapelais G Kuhnle GG Luben R Khaw KT Bingham S;European Prospective into Cancer-Norfolk cohort 《Breast cancer research : BCR》2008,10(2):R32-9
Introduction
Phytoestrogens are a group of compounds found in plants that structurally resemble the hormone oestradiol, and thus have the potential to act as oestrogen agonists or antagonists. Their potential effects may alter the risk of breast cancer, but only a limited range of phytoestrogens has been examined in prospective cohort studies.Methods
Serum and urine samples from 237 incident breast cancer cases and 952 control individuals (aged 45 to 75 years) in the European Prospective into Cancer-Norfolk cohort were analysed for seven phytoestrogens (daidzein, enterodiol, enterolactone, genistein, glycitein, o-desmethylangolensin, and equol) using liquid chromatography/mass spectrometry. Data on participants' diet, demographics, anthropometrics, and medical history were collected upon recruitment. All models were adjusted for weight, fat and energy intake, family history of breast cancer, social class, analytical batch, and factors related to oestrogen exposure.Results
Urinary or serum phytoestrogens were not associated with protection from breast cancer in the European Prospective into Cancer-Norfolk cohort. Breast cancer risk was marginally increased with higher levels of total urinary isoflavones (odds ratio = 1.08 (95% confidence interval = 1.00 to 1.16), P = 0.055); among those with oestrogen receptor-positive tumours, the risk of breast cancer was increased with higher levels of urinary equol (odds ratio = 1.07 (95% confidence interval = 1.01 to 1.12), P = 0.013).Conclusion
There was limited evidence of an association between phytoestrogen biomarkers and breast cancer risk in the present study. There was no indication of decreased likelihood of breast cancer with higher levels of phytoestrogen biomarkers, but the observation that some phytoestrogen biomarkers may be associated with greater risk of breast cancer warrants further study with greater statistical power. 相似文献75.
76.
77.
Monocytes stimulate fibroblastoid bone marrow stromal cells to produce multilineage hematopoietic growth factors 总被引:7,自引:0,他引:7
In previous studies we have found that monocytes produce soluble factors that stimulate human umbilical vein endothelial cells to produce granulocyte-macrophage colony-stimulating activity (CSA), burst- promoting activity (BPA), and megakaryocyte colony-stimulating activity (Meg-CSA) as well as factors that stimulate T lymphocytes and neonatal fibroblasts to produce CSA. To test the hypothesis that monocytes would similarly stimulate the production of hematopoietic growth factors by autologous bone marrow stromal cells, multiply-passaged adherent fibroblastoid cells derived from the bone marrow of normal volunteers were exposed to conditioned media prepared by incubating autologous peripheral blood monocytes in complete medium for three days. When conditioned media from stromal cells incubated in monocyte-conditioned medium were compared with those of stromal cells cultured in the absence of monocyte-conditioned medium, BPA was increased fourfold and CSA was increased more than 30-fold. We conclude that mononuclear phagocytes recruit stromal cells of the marrow to produce multilineage growth factors in vitro. We suggest that these monocyte-derived recruiting activities may play an important role in orchestration of hematopoietic growth factor production by cells of the marrow microenvironment. 相似文献
78.
79.
80.