收费全文 | 2536篇 |
免费 | 406篇 |
国内免费 | 6篇 |
耳鼻咽喉 | 18篇 |
儿科学 | 52篇 |
妇产科学 | 35篇 |
基础医学 | 134篇 |
口腔科学 | 1565篇 |
临床医学 | 165篇 |
内科学 | 239篇 |
皮肤病学 | 39篇 |
神经病学 | 57篇 |
特种医学 | 35篇 |
外科学 | 170篇 |
综合类 | 22篇 |
预防医学 | 90篇 |
眼科学 | 70篇 |
药学 | 123篇 |
中国医学 | 12篇 |
肿瘤学 | 122篇 |
2024年 | 13篇 |
2023年 | 132篇 |
2022年 | 75篇 |
2021年 | 121篇 |
2020年 | 73篇 |
2019年 | 80篇 |
2018年 | 145篇 |
2017年 | 155篇 |
2016年 | 135篇 |
2015年 | 140篇 |
2014年 | 176篇 |
2013年 | 146篇 |
2012年 | 141篇 |
2011年 | 118篇 |
2010年 | 121篇 |
2009年 | 132篇 |
2008年 | 67篇 |
2007年 | 53篇 |
2006年 | 52篇 |
2005年 | 37篇 |
2004年 | 31篇 |
2003年 | 30篇 |
2002年 | 27篇 |
2001年 | 38篇 |
2000年 | 32篇 |
1999年 | 34篇 |
1998年 | 79篇 |
1997年 | 48篇 |
1996年 | 54篇 |
1995年 | 37篇 |
1994年 | 47篇 |
1993年 | 41篇 |
1992年 | 32篇 |
1991年 | 40篇 |
1990年 | 30篇 |
1989年 | 37篇 |
1988年 | 29篇 |
1987年 | 20篇 |
1986年 | 21篇 |
1985年 | 18篇 |
1984年 | 13篇 |
1983年 | 5篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 13篇 |
1978年 | 15篇 |
1977年 | 4篇 |
1976年 | 8篇 |
1975年 | 4篇 |
Background
Local recurrence in oral squamous cell carcinoma (OSCC) despite clear surgical margins may indicate the presence of residual, sub-microscopic disease. Molecular assessment of surgical margins may provide a greater prognostic sensitivity compared to histopathology. We aimed to determine whether promoter methylation in deep and mucosal resection margins can predict recurrence in OSCC.Methods
Forty-eight consecutive OSCC cases were recruited and a 5 mm3 tumor sample plus 5 deep and 5 mucosal margin samples were snap frozen. Clinical, pathological, adjuvant therapy, and outcome data were recorded. Tumors were informative if >5 % promoter methylation was found for ≥1 of 4 genes using qMSP. Margins were declared molecularly positive if >1 % promoter methylation was found in any margin.Results
Thirty (63 %) of 48 cases were methylation informative. Mucosal margin samples were largely positive for methylation (26 of 30, 87 %), indicating the presence of field cancerization. Methylation at ≥1 gene promoters in ≥1 deep margin correlated with the presence of close/involved mucosal margins (P = 0.027) and increased pT status (P = 0.027) but not the status of deep margins, recurrence, or survival.Conclusions
The current gene panel did not add prognostic information to histopathological reporting of resection margins. Future efforts should concentrate on improving gene selection, informativity, and assay performance in the patient group with intermediate indications for adjuvant therapy. 相似文献![点击此处可从《Head & neck》网站下载免费的PDF全文](/ch/ext_images/free.gif)
![点击此处可从《Head & neck》网站下载免费的PDF全文](/ch/ext_images/free.gif)
![点击此处可从《Health expectations》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Objective: This study was aimed to investigate the effects of pre-pubertal exposure of Ara-C on testesticular development in juvenile SD rats and their function at puberty.
Materials and methods: Ara-C was injected at the doses of 50, 100 and 200?mg/kg/day from postnatal day (PND) 29–42 (14 days) by intraperitoneal (i.p.) route. Half of the animals were sacrificed on PND 43 and remaining on PND 70. End points of the evaluation included gross pathological examination, histomorphometric analysis, sperm count and sperm head morphology, cell proliferation and DNA damage as well as apoptosis analysis.
Results: Ara-C treatment significantly decreased food and water intake, weight gain, testes and epididymis weight and increased histological alterations in the seminiferous tubule. Furthermore, Ara-C treatment significantly decreased the PCNA-positive cells and sperm count in a dose-dependent manner. Ara-C treatment also increased the DNA damage and apoptosis in testes and sperm as evident from the comet and TUNEL assays results.
Discussion: The present study results clearly indicated that Ara-C treatment impaired spermatogenesis and adversely affects the testicular development and its function in rats by reducing the germ cell proliferation and the inducing DNA damage and apoptosis. 相似文献