首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1381881篇
  免费   100940篇
  国内免费   6699篇
耳鼻咽喉   20207篇
儿科学   40882篇
妇产科学   39592篇
基础医学   192848篇
口腔科学   40648篇
临床医学   119045篇
内科学   268153篇
皮肤病学   30792篇
神经病学   109020篇
特种医学   55792篇
外国民族医学   487篇
外科学   212981篇
综合类   38800篇
现状与发展   25篇
一般理论   439篇
预防医学   95102篇
眼科学   32858篇
药学   105705篇
  63篇
中国医学   5890篇
肿瘤学   80191篇
  2018年   13871篇
  2017年   11394篇
  2016年   12366篇
  2015年   14473篇
  2014年   19915篇
  2013年   27916篇
  2012年   37240篇
  2011年   39581篇
  2010年   23577篇
  2009年   22392篇
  2008年   36566篇
  2007年   39686篇
  2006年   40268篇
  2005年   38995篇
  2004年   37043篇
  2003年   35947篇
  2002年   35160篇
  2001年   64565篇
  2000年   66311篇
  1999年   56288篇
  1998年   14697篇
  1997年   13432篇
  1996年   12739篇
  1995年   12727篇
  1994年   11882篇
  1992年   43079篇
  1991年   41578篇
  1990年   40813篇
  1989年   39757篇
  1988年   37157篇
  1987年   36569篇
  1986年   35058篇
  1985年   33235篇
  1984年   24881篇
  1983年   21052篇
  1982年   12647篇
  1981年   11547篇
  1979年   23939篇
  1978年   17049篇
  1977年   14780篇
  1976年   13347篇
  1975年   15252篇
  1974年   18079篇
  1973年   17555篇
  1972年   16808篇
  1971年   15709篇
  1970年   14881篇
  1969年   14331篇
  1968年   13453篇
  1967年   11998篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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.
3.
Major depressive disorder is a serious and common neuropsychiatric disorder that affects more than 350 million people worldwide. Electroconvulsive therapy is the oldest and most effective treatment available for the treatment of severe major depressive disorder. Electroconvulsive therapy modifies structural network changes in patients with major depressive disorder and schizophrenia. And it can also affect neuroinflammatory responses and may have neuroprotective effects. Electroconvulsive therapy plays an irreplaceable role in the treatment of major depressive disorder.  相似文献   
4.
Oral squamous cell carcinomas (OSCCs) develop in genetically altered epithelium in the mucosal lining, also coined as fields, which are mostly not visible but occasionally present as white oral leukoplakia (OL) lesions. We developed a noninvasive genetic assay using next-generation sequencing (NGS) on brushed cells to detect the presence of genetically altered fields, including those that are not macroscopically visible. The assay demonstrated high accuracy in OL patients when brush samples were compared with biopsies as gold standard. In a cohort of Fanconi anemia patients, detection of mutations in prospectively collected oral brushes predicted oral cancer also when visible abnormalities were absent. We further provide insight in the molecular landscape of OL with frequent changes of TP53, FAT1 and NOTCH1. NGS analysis of noninvasively collected samples offers a highly accurate method to detect genetically altered fields in the oral cavity, and predicts development of OSCC in high-risk individuals. Noninvasive genetic screening can be employed to screen high-risk populations for cancer and precancer, map the extension of OL lesions beyond what is visible, map the oral cavity for precancerous changes even when visible abnormalities are absent, test accuracy of promising imaging modalities, monitor interventions and determine genetic progression as well as the natural history of the disease in the human patient.  相似文献   
5.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz -  相似文献   
6.
7.
Immunologic Research - Hyper immunoglobulin M (HIGM) syndrome is a rare disorder of the immune system with impaired antibody functions. The clinical picture of the patients varies according to the...  相似文献   
8.
采用文献复习和实证研究经验的方法对《医疗质量管理办法》中涉及的医疗质量概念及相关问题进行探讨。《医疗质量管理办法》中的医疗质量的定义存在重大缺失,没有涉及医疗服务的结果,特别是患者安全。医疗质量的定义应与国际相关权威机构保持一致,应高度重视医疗服务的结果,特别是患者安全。  相似文献   
9.
10.
Postbariatric loss of muscle tissue could negatively affect long-term health due to its role in various bodily processes, such as metabolism and functional capacity. This meta-analysis aimed to unravel time-dependent changes in the magnitude and progress of lean body mass (LBM), fat-free mass (FFM), and skeletal muscle mass (SMM) loss following bariatric surgery. A systematic literature search was conducted in Pubmed, Embase, and Web of Science. Fifty-nine studies assessed LBM (n = 37), FFM (n = 20), or SMM (n = 3) preoperatively and ≥1 time points postsurgery. Random-effects meta-analyses were performed to determine pooled loss per outcome parameter and follow-up time point. At 12-month postsurgery, pooled LBM loss was ?8.13 kg [95%CI ?9.01; ?7.26]. FFM loss and SMM loss were ?8.23 kg [95%CI ?10.74; ?5.73] and ?3.18 kg [95%CI ?5.64; ?0.71], respectively. About 55% of 12-month LBM loss occurred within 3-month postsurgery, followed by a more gradual decrease up to 12 months. Similar patterns were seen for FFM and SMM. In conclusion, >8 kg of LBM and FFM loss was observed within 1-year postsurgery. LBM, FFM, and SMM were predominantly lost within 3-month postsurgery, highlighting that interventions to mitigate such losses should be implemented perioperatively.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号