全文获取类型
收费全文 | 56353篇 |
免费 | 4881篇 |
国内免费 | 99篇 |
专业分类
耳鼻咽喉 | 411篇 |
儿科学 | 2059篇 |
妇产科学 | 1853篇 |
基础医学 | 7299篇 |
口腔科学 | 991篇 |
临床医学 | 8927篇 |
内科学 | 10053篇 |
皮肤病学 | 838篇 |
神经病学 | 5278篇 |
特种医学 | 1243篇 |
外科学 | 5538篇 |
综合类 | 944篇 |
一般理论 | 89篇 |
预防医学 | 7328篇 |
眼科学 | 626篇 |
药学 | 3736篇 |
中国医学 | 60篇 |
肿瘤学 | 4060篇 |
出版年
2023年 | 297篇 |
2022年 | 330篇 |
2021年 | 890篇 |
2020年 | 695篇 |
2019年 | 1200篇 |
2018年 | 1242篇 |
2017年 | 928篇 |
2016年 | 1080篇 |
2015年 | 1231篇 |
2014年 | 1607篇 |
2013年 | 2493篇 |
2012年 | 3535篇 |
2011年 | 3663篇 |
2010年 | 2020篇 |
2009年 | 1828篇 |
2008年 | 3303篇 |
2007年 | 3633篇 |
2006年 | 3470篇 |
2005年 | 3266篇 |
2004年 | 3174篇 |
2003年 | 2983篇 |
2002年 | 2812篇 |
2001年 | 987篇 |
2000年 | 931篇 |
1999年 | 898篇 |
1998年 | 731篇 |
1997年 | 576篇 |
1996年 | 535篇 |
1995年 | 526篇 |
1994年 | 425篇 |
1993年 | 435篇 |
1992年 | 677篇 |
1991年 | 635篇 |
1990年 | 567篇 |
1989年 | 659篇 |
1988年 | 541篇 |
1987年 | 485篇 |
1986年 | 555篇 |
1985年 | 489篇 |
1984年 | 417篇 |
1983年 | 437篇 |
1982年 | 320篇 |
1981年 | 309篇 |
1980年 | 278篇 |
1979年 | 297篇 |
1978年 | 244篇 |
1977年 | 222篇 |
1976年 | 218篇 |
1974年 | 201篇 |
1973年 | 217篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
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
3.
4.
5.
Factors predicting the development of pressure ulcers in an at‐risk population who receive standardized preventive care: secondary analyses of a multicentre randomised controlled trial 下载免费PDF全文
6.
7.
8.
Andrea Stracciolini Jennifer Luz Gregory Walker Nicholas M. Edwards Avery D. Faigenbaum Gregory D. Myer 《The Physician and sportsmedicine》2020,48(2):199-207
ABSTRACT
Objective
To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline. 相似文献9.
Emma J. Walker Noni E. MacDonald Nehal Islam Nicole Le Saux Karina A. Top Deshayne B. Fell 《Vaccine》2019,37(13):1725-1735
Objective
To systematically review literature on uptake and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and/or polio-containing vaccines in infants who were born preterm, with a low birth weight, and/or with chronic health conditions that were diagnosed within the first 6?months of life.Methods
Using a standardized search strategy developed by a medical librarian, records were extracted from MEDLINE, Embase, Database of Abstracts of Reviews of Effects, and CINAHL up to May 8, 2018.Results
Out of the 1997 records that were screened, we identified 21 studies that met inclusion criteria. Eleven studies assessed vaccine coverage and/or timeliness in preterm infants, 6 in low birth weight infants, and 7 in children with chronic health conditions. Estimates of coverage in these populations were highly variable, ranging from 40% to 100% across the vaccines and population groups.Conclusions
There is a lack of studies reporting coverage and timeliness of routine immunizations in special populations of children.Policy implications
Our review suggests a need for improved surveillance of immunization status in special populations of infants, as well as a need for standardization of reporting practices. 相似文献10.