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   1801642篇
  免费   133364篇
  国内免费   3724篇
耳鼻咽喉   24568篇
儿科学   55185篇
妇产科学   48585篇
基础医学   258781篇
口腔科学   53092篇
临床医学   160902篇
内科学   349982篇
皮肤病学   39576篇
神经病学   141545篇
特种医学   70109篇
外国民族医学   370篇
外科学   281293篇
综合类   39250篇
现状与发展   1篇
一般理论   603篇
预防医学   131591篇
眼科学   41554篇
药学   135196篇
  6篇
中国医学   3841篇
肿瘤学   102700篇
  2018年   17952篇
  2017年   14029篇
  2016年   15816篇
  2015年   17964篇
  2014年   24444篇
  2013年   36840篇
  2012年   49289篇
  2011年   51999篇
  2010年   31075篇
  2009年   29493篇
  2008年   49740篇
  2007年   52515篇
  2006年   53607篇
  2005年   51502篇
  2004年   50053篇
  2003年   48124篇
  2002年   46867篇
  2001年   93311篇
  2000年   96124篇
  1999年   80345篇
  1998年   20519篇
  1997年   18177篇
  1996年   18350篇
  1995年   17404篇
  1994年   16158篇
  1993年   14922篇
  1992年   62926篇
  1991年   60830篇
  1990年   59332篇
  1989年   57637篇
  1988年   52457篇
  1987年   51852篇
  1986年   48346篇
  1985年   46530篇
  1984年   33991篇
  1983年   28782篇
  1982年   16085篇
  1981年   14310篇
  1979年   30803篇
  1978年   21484篇
  1977年   18266篇
  1976年   16637篇
  1975年   17872篇
  1974年   21609篇
  1973年   20635篇
  1972年   19342篇
  1971年   18068篇
  1970年   17057篇
  1969年   15929篇
  1968年   14627篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
11.
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   
12.
Introduction: Percutaneous renal mass biopsy has evolved over the last decade with improvements on previous pitfalls including low tissue yield, high non-diagnostic rates, and complications. As understanding of tumor biology and natural history of renal cortical neoplasms has improved, percutaneous renal mass biopsy is poised to have an expanding role in an area characterized by individualized management and refined risk stratification.

Areas covered: This review summarizes the evolution of renal mass biopsy to its current state with respect to outcomes, indications, and clinical guidelines.

Expert opinion: With improved understanding of differential biological potential of renal cortical neoplasms combined with technical improvements in diagnostic yield and accuracy, utilization of renal mass biopsy is becoming an important adjunct to patient care in a broad range of clinical scenarios, including active surveillance, thermal ablation, and use of primary systemic therapy in localized and advanced settings.  相似文献   

13.
Introduction: Pharmacovigilance is essential to monitoring the safety profiles of authorized medicines. Compared with small-molecule drugs, biological drugs are more complex, more susceptible to structural variability due to manufacturing processes, and have the potential to induce immune-related reactions, underscoring the importance of safety monitoring for these products. Although highly similar to reference products, biosimilars are not expected to be structurally identical. For these reasons, proper reporting of potential adverse drug reactions (ADRs) using distinguishable names and batch numbers is essential for accurate tracing of all biological drugs. To address the need for robust pharmacovigilance, the European Parliament and Council of the European Union provided legislation regarding pharmacovigilance of biologics in 2010.

Areas covered: This narrative review examines the current state of pharmacovigilance for biologics in the European Union (EU) and discusses relevant information on pharmacovigilance of biosimilars, the current EU pharmacovigilance system, and areas that could be improved.

Expert opinion: Although steps have been taken to improve pharmacovigilance of biologics in the EU, several enhancements can still be made, including additional training for healthcare professionals on ADR reporting, the use of 2D barcodes that enhance traceability, and an open discussion of potentially missed opportunities in the pharmacovigilance of biosimilars.  相似文献   

14.
15.
16.
17.
18.
19.
20.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  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