全文获取类型
收费全文 | 28374篇 |
免费 | 2228篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 233篇 |
儿科学 | 1036篇 |
妇产科学 | 866篇 |
基础医学 | 3529篇 |
口腔科学 | 435篇 |
临床医学 | 5152篇 |
内科学 | 4917篇 |
皮肤病学 | 391篇 |
神经病学 | 2667篇 |
特种医学 | 529篇 |
外科学 | 2278篇 |
综合类 | 391篇 |
一般理论 | 64篇 |
预防医学 | 3933篇 |
眼科学 | 343篇 |
药学 | 1620篇 |
中国医学 | 26篇 |
肿瘤学 | 2258篇 |
出版年
2023年 | 161篇 |
2022年 | 220篇 |
2021年 | 490篇 |
2020年 | 416篇 |
2019年 | 715篇 |
2018年 | 738篇 |
2017年 | 553篇 |
2016年 | 661篇 |
2015年 | 727篇 |
2014年 | 918篇 |
2013年 | 1447篇 |
2012年 | 1985篇 |
2011年 | 2007篇 |
2010年 | 1114篇 |
2009年 | 1010篇 |
2008年 | 1890篇 |
2007年 | 2023篇 |
2006年 | 2015篇 |
2005年 | 1913篇 |
2004年 | 1796篇 |
2003年 | 1725篇 |
2002年 | 1627篇 |
2001年 | 240篇 |
2000年 | 201篇 |
1999年 | 237篇 |
1998年 | 407篇 |
1997年 | 282篇 |
1996年 | 275篇 |
1995年 | 261篇 |
1994年 | 230篇 |
1993年 | 224篇 |
1992年 | 139篇 |
1991年 | 114篇 |
1990年 | 110篇 |
1989年 | 121篇 |
1988年 | 104篇 |
1987年 | 81篇 |
1986年 | 100篇 |
1985年 | 122篇 |
1984年 | 103篇 |
1983年 | 111篇 |
1982年 | 137篇 |
1981年 | 135篇 |
1980年 | 137篇 |
1979年 | 51篇 |
1978年 | 57篇 |
1977年 | 58篇 |
1976年 | 63篇 |
1975年 | 50篇 |
1974年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 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.
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
![点击此处可从《Journal of advanced nursing》网站下载免费的PDF全文](/ch/ext_images/free.gif)
3.
4.
5.
6.
7.
Ann S. O’Malley Kevin Draper Rebecca Gourevitch Dori A. Cross Sarah Hudson Scholle 《J Am Med Inform Assoc》2015,22(2):426-434
Objective Consensus that enhanced teamwork is necessary for efficient and effective primary care delivery is growing. We sought to identify how electronic health records (EHRs) facilitate and pose challenges to primary care teams as well as how practices are overcoming these challenges.Methods Practices in this qualitative study were selected from those recognized as patient-centered medical homes via the National Committee for Quality Assurance 2011 tool, which included a section on practice teamwork. We interviewed 63 respondents, ranging from physicians to front-desk staff, from 27 primary care practices ranging in size, type, geography, and population size.Results EHRs were found to facilitate communication and task delegation in primary care teams through instant messaging, task management software, and the ability to create evidence-based templates for symptom-specific data collection from patients by medical assistants and nurses (which can offload work from physicians). Areas where respondents felt that electronic medical record EHR functionalities were weakest and posed challenges to teamwork included the lack of integrated care manager software and care plans in EHRs, poor practice registry functionality and interoperability, and inadequate ease of tracking patient data in the EHR over time.Discussion Practices developed solutions for some of the challenges they faced when attempting to use EHRs to support teamwork but wanted more permanent vendor and policy solutions for other challenges.Conclusions EHR vendors in the United States need to work alongside practicing primary care teams to create more clinically useful EHRs that support dynamic care plans, integrated care management software, more functional and interoperable practice registries, and greater ease of data tracking over time. 相似文献
8.
Lee Mi Jung Romero Sergio Velozo Craig A. Gruber-Baldini Ann L. Shulman Lisa M. 《Quality of life research》2019,28(6):1595-1603
Quality of Life Research - This study investigated the PROMIS Self-Efficacy Measure for Managing Chronic Conditions (PROMIS-SE) domain distributions and examined the factor structure of the... 相似文献
9.
Joseph Biederman Haitao Gao Ann K Rogers Thomas J Spencer 《Neuropsychopharmacology》2006,60(10):1106-1110
BACKGROUND: The validity of parent reports regarding children's attention-deficit/hyperactivity disorder (ADHD) symptoms has been questioned. This study assessed whether parent reports were as sensitive as teacher reports to document change in ADHD symptoms during clinical trials with atomoxetine. METHODS: Data were compared from two randomized, double-blind, placebo-controlled clinical trials of atomoxetine using different versions (parent or teacher) of the same rating scale (Attention-Deficit/Hyperactivity Disorder Rating Scale-IV [parent or teacher] Version: Investigator Administered and Scored - ADHD RS). Exclusion criteria included history of bipolar disorder, psychosis, seizures, alcohol abuse, or positive drug screen. Patients (6-16 years old) were treated with atomoxetine (titrated to a maximum dose of 1.8 mg/kg/day) administered once daily for up to 7 weeks. Parent and teacher ratings were compared using an analysis of covariance (ANCOVA) model. RESULTS: The analysis (n = 318) showed that treatment effects (mean change, baseline to endpoint) were similar between parent and teacher ratings (total, p = .762; inattention, p = .519; hyperactive/impulsive, p = .955). Effect sizes also were similar based on total scores (parent ratings = .69; teacher ratings = .63). CONCLUSIONS: Parent reports are as sensitive as teacher reports in assessing the efficacy of long-acting pharmacologic treatment for ADHD in children during clinical trials using the nonstimulant atomoxetine. 相似文献
10.
Jonathan Halford Gandis Mazeika Susan Slifer Marcy Speer Ann M Saunders Warren J Strittmatter Joel C Morgenlander 《Movement disorders》2006,21(4):540-542
Ninety-seven inpatients with tardive dyskinesia (average AIMS score = 13), the majority of whom were schizophrenic, were studied. Forty patients were Caucasian, and 57 were African-American. The APOE genotypes of these patients were compared to previously published genotypes of controls and with previously published studies of APOE genotypes in patients with schizophrenia. There were no significant differences in APOE allele frequencies comparing the African-American tardive dyskinesia population and the African-American control groups. In contrast, significant (< 0.05) P values were obtained comparing the Caucasian tardive dyskinesia population to the Caucasian controls, when comparing allele frequencies and genotypic frequencies. This study suggests that Caucasians bearing an APOE2 allele are at increased risk of developing tardive dyskinesia, whereas African-Americans are not. APOE genotype-specific risks of both tardive dyskinesia and Alzheimer's disease that vary across populations could be due to recruitment of patients or controls or could be due to modifying effects of differing genetic or environmental backgrounds. The mechanism by which the APOE2 allele increases risk of tardive dyskinesia is not known. Further information about the mechanisms of increased risk of tardive dyskinesia could result in stratification of prescribing practices weighing the costs of medications against the relative risk of side effects. 相似文献