全文获取类型
收费全文 | 1085篇 |
免费 | 74篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 22篇 |
妇产科学 | 19篇 |
基础医学 | 143篇 |
口腔科学 | 24篇 |
临床医学 | 81篇 |
内科学 | 312篇 |
皮肤病学 | 11篇 |
神经病学 | 25篇 |
特种医学 | 15篇 |
外科学 | 252篇 |
综合类 | 6篇 |
预防医学 | 65篇 |
眼科学 | 6篇 |
药学 | 54篇 |
肿瘤学 | 134篇 |
出版年
2023年 | 14篇 |
2022年 | 26篇 |
2021年 | 52篇 |
2020年 | 23篇 |
2019年 | 26篇 |
2018年 | 39篇 |
2017年 | 31篇 |
2016年 | 31篇 |
2015年 | 32篇 |
2014年 | 34篇 |
2013年 | 49篇 |
2012年 | 85篇 |
2011年 | 85篇 |
2010年 | 47篇 |
2009年 | 41篇 |
2008年 | 85篇 |
2007年 | 89篇 |
2006年 | 73篇 |
2005年 | 63篇 |
2004年 | 52篇 |
2003年 | 44篇 |
2002年 | 56篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1971年 | 2篇 |
1930年 | 1篇 |
1929年 | 2篇 |
1903年 | 1篇 |
1902年 | 2篇 |
排序方式: 共有1175条查询结果,搜索用时 15 毫秒
1.
2.
In the context of a medical surveillance program aimed at preventing cancer risk from exposure to ionizing radiation, we investigated chromosomal damage in peripheral lymphocytes from 37 hospital workers exposed to low levels of ionizing radiation and 37 controls. The micronuleus (MN) assay was used as a biomarker of genetic damage. The influence of confounding factors like smoking status, age and gender was investigated by multiple regression analysis. The results indicated that, overall, MN frequency was higher in exposed workers than in controls, although the difference was not statistically significant. Interestingly, smoking status significantly raised MN frequency among the exposed workers but not among controls. This suggests that smoking can influence chromosomal damage induced in humans by ionizing radiation. Among both exposed workers and controls, MN frequency was found to increase with age. Female gender influenced the increase in MN frequency in the exposed group. Our results suggest that the effect of cigarette smoking should be carefully factored into genetic monitoring studies assessing the risks associated with low level radiation exposure. 相似文献
3.
Both Human Immunodeficiency Virus Cellular DNA Sequencing and Plasma RNA Sequencing Are Useful for Detection of Drug Resistance Mutations in Blood Samples from Antiretroviral-Drug-Naive Patients 下载免费PDF全文
4.
Leonard A. Herzenberg Charles Hsu Saverio Alberti Paula Kavathas 《Medical oncology (Northwood, London, England)》1984,1(4):219-224
In order to facilitate cloning of genes for cell surface molecules, we cotransfected LTK? mouse fibroblasts with thymidine kinase (TK) genes and total human or mouse DNA. TK+ cells, selected by growth in HAT medium, were stained with fluorochrome conjugated monoclonal antibodies or other fluorescent ligands which bind to one or another membrane differentiation antigen or receptor. We isolated fluorescent transfectants expressing these molecules using a fluorescence activated cell sorter (FACS). For some antigens, spontaneous gene amplification occurred. By repeated cycles of FACS sorting and regrowth we obtained high expressing clones. We then isolatedcDNA and genomic clones using selectedcDNA probes to screen phage withcDNA inserts. DNA from virtually any tissue source transfected equally well for the various molecules except for DNA from a trophoblast derived choriocarcinoma cell line which did not transfect for Leu-2. 相似文献
5.
Barbara Colitti Luigi Bertolotti Alessandro Mannelli Gianmarco Ferrara Andrea Vercelli Andrea Grassi Claudio Trentin Saverio Paltrinieri Chiara Nogarol Nicola Decaro Emiliana Brocchi Sergio Rosati 《Emerging infectious diseases》2021,27(7):1919
We conducted a serologic survey among dogs and cats in Italy to detect antibodies against severe acute respiratory syndrome virus 2 (SARS-CoV-2). We found that SARS-CoV-2 seroprevalence was higher among cats (16.2%) than dogs (2.3%). In addition, seroprevalence was higher among animals living in close contact with SARS-CoV-2–positive owners. 相似文献
6.
Metformin Decreases Circulating Androgen and Estrogen Levels in Nondiabetic Women With Breast Cancer
Carlo Campagnoli Franco Berrino Elisabetta Venturelli Chiara Abbà Nicoletta Biglia Tiziana Brucato Patrizia Cogliati Saverio Danese Michela Donadio Gianna Zito Patrizia Pasanisi 《Clinical breast cancer》2013,13(6):433-438
IntroductionDiabetic patients treated with metformin have a lower risk of developing BC or a better BC prognosis. Metformin might reduce cancer growth through direct antiproliferative effects or through indirect mechanisms, particularly the reduction of insulin. In a randomized study on nondiabetic BC patients in natural menopause with high testosterone levels, we observed a significant decrease in insulin and in testosterone levels with metformin 1500 mg/d compared with 1000 mg/d. We present the results of a new analysis of our study on the effect of metformin on the bioavailability of sex hormones.Patients and MethodsOne hundred twenty-four eligible women were initially invited to take metformin 500 mg/d for 3 months. The 108 women who completed the first 3 months continued the study using 1000 mg/d for 1 month. The women were then randomized into 2 groups, and, for the subsequent 5 months, 1 group increased the dose to 1500 mg/d, and the other group continued with 1000 mg/d.ResultsNinety-six women completed the study, 43 receiving metformin 1500 mg/day, and 53 receiving 1000 mg/day. The women receiving 1500 mg/d showed a greater and significant reduction of free testosterone (?29%) and estradiol (?38%), a borderline significant reduction of estrone and insulin-like growth factor-1, and a nonsignificant reduction of androstenedione. They also showed a nonsignificant increase of dehydroepiandrosterone sulfate.ConclusionMetformin does not interfere with the production of dehydroepiandrosterone sulfate. Besides, it decreases estradiol levels, basically through the reduction of testosterone. These hormonal changes might have clinical relevance. 相似文献
7.
Zampieri N Borruto F Zamboni C Camoglio FS 《Archives of gynecology and obstetrics》2008,277(4):303-306
Background Abdominal cystic formations in newborns are relatively common and often diagnostic suspicion arises in this regard even before
birth as a result of ultrasound scans carried out during pregnancy. The aim of this study is to highlight the problems posed
by the prenatal diagnosis of abdominal cysts in order to outline the most appropriate therapeutic approach in case of suspected
ovarian cysts.
Materials and methods Between January 2003 and January 2007, 57 women were enrolled in this study for a prenatal ultrasound (US) that revealed the
presence of an echo-rare or echo-free area in the foetal abdomen. After birth all babies underwent blood tests and abdominal
US scans in order to confirm or identify the nature of the cyst. If abdominal US could not show the nature of the cystic formation,
magnetic resonance imaging with sedation was performed. When the radiological tests were not useful to identify the nature
of the cysts and surgery was then necessary, surgical procedures were performed with laparoscopy.
Results Ultrasounds were useful to identify the diameter of the cysts but not all their origins; also MRI confirmed the morphology
and volume of the cysts, but could not give further details about their origin.
Discussion Abdominal ultrasound and finally laparoscopy used to treat and remove the cysts were useful to monitor all simple abdominal
cysts. MRI seemed not to be useful for the treatment of this condition, especially in the pediatric age when mild sedation
is required. 相似文献
8.
9.
Paolo De Pasquale Erasmo Rubino Daniele Borzelli Matteo Peditto Enrico Nastro Siniscalchi Francesco Saverio De Ponte Giacomo Oteri Andrea dAvella 《Materials》2022,15(11)
Assessing maximum voluntary bite force is important to characterize the functional state of the masticatory system. Due to several factors affecting the estimation of the maximum bite force, a unique solution combining desirable features such as reliability, accuracy, precision, usability, and comfort is not available. The aim of the present study was to develop a low-cost bite force measurement device allowing for subject-specific customization, comfortable bite force expression, and reliable force estimation over time. The device was realized using an inexpensive load cell, two 3D printed ergonomic forks hosting reusable subject-specific silicone molds, a read-out system based on a low-cost microcontroller, and a wireless link to a personal computer. A simple model was used to estimate bite force taking into account individual morphology and device placement in the mouth. Measurement reliability, accuracy, and precision were assessed on a calibration dataset. A validation procedure on healthy participants was performed to assess the repeatability of the measurements over multiple repetitions and sessions. A 2% precision and 2% accuracy were achieved on measurements of forces in the physiological range of adult bite forces. Multiple recordings on healthy participants demonstrated good repeatability (coefficient of variation 11%) with no significant effect of repetition and session. The novel device provides an affordable and reliable solution for assessing maximum bite force that can be easily used to perform clinical evaluations in single sessions or in longitudinal studies. 相似文献
10.
Alessandro Franchi Saverio Frosinil Vieri Boddi 《国际眼科杂志》2006,6(4):769-774
目的:评估新的微小切口白内障手术(MICS)是否较标准同轴晶状体乳化引起较少的内皮损害方法:年龄相关性白内障患者 200 例随机分配接受标准同轴晶状体乳化(SCP)或 MICS 晶状体乳化。术前及术后1a 测量角膜中央及 12 点内皮细胞计数、细胞大小变异系数、六角形细胞百分比以及角膜中央厚度。结果:患者 173 例完成了试验。在 1a 的随访检查中,MICS 组内皮细胞损失为 6.5204%,而 SCP 组为 8.726%(P<0.00005)。两组在细胞大小变异系数、六角形细胞百分比、术后角膜厚度以及在切口部位和角膜中央测得的内皮细胞密度变异方面无显著差异。在硬性白内障患者中,与手术步骤无关,内皮细胞密度损失的增加量较高。结论:比较 SCP 与 MICS,本研究表明后者引起的内皮细胞密度损失明显地较低。 相似文献