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   3314588篇
  免费   253603篇
  国内免费   6350篇
耳鼻咽喉   49831篇
儿科学   103419篇
妇产科学   91468篇
基础医学   463116篇
口腔科学   99059篇
临床医学   294902篇
内科学   638920篇
皮肤病学   71502篇
神经病学   275396篇
特种医学   133494篇
外国民族医学   1263篇
外科学   507883篇
综合类   78768篇
一般理论   1324篇
预防医学   254641篇
眼科学   80818篇
药学   249355篇
  6篇
中国医学   6466篇
肿瘤学   172910篇
  2018年   33029篇
  2016年   28857篇
  2015年   32648篇
  2014年   46307篇
  2013年   70570篇
  2012年   94990篇
  2011年   99756篇
  2010年   58744篇
  2009年   56204篇
  2008年   95286篇
  2007年   102281篇
  2006年   103175篇
  2005年   101193篇
  2004年   97390篇
  2003年   94420篇
  2002年   93104篇
  2001年   151912篇
  2000年   156797篇
  1999年   132506篇
  1998年   35865篇
  1997年   32298篇
  1996年   31446篇
  1995年   32217篇
  1994年   30212篇
  1993年   28080篇
  1992年   105665篇
  1991年   102071篇
  1990年   99063篇
  1989年   95822篇
  1988年   88992篇
  1987年   87737篇
  1986年   83527篇
  1985年   79836篇
  1984年   60279篇
  1983年   51251篇
  1982年   31149篇
  1981年   27882篇
  1979年   57224篇
  1978年   40460篇
  1977年   34524篇
  1976年   31867篇
  1975年   34734篇
  1974年   42202篇
  1973年   40466篇
  1972年   38365篇
  1971年   35742篇
  1970年   33753篇
  1969年   31631篇
  1968年   29190篇
  1967年   26203篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
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.
Modified-release opioids are often prescribed for the management of moderate to severe acute pain following total hip and knee arthroplasty, despite recommendations against their use due to increasing concerns regarding harm. The primary objective of this multicentre study was to examine the impact of modified-release opioid use on the incidence of opioid-related adverse events compared with immediate-release opioid use, among adult inpatients following total hip or knee arthroplasty. Data for total hip and knee arthroplasty inpatients receiving an opioid analgesic for postoperative analgesia during hospitalisation were collected from electronic medical records of three tertiary metropolitan hospitals in Australia. The primary outcome was the incidence of opioid-related adverse events during hospital admission. Patients who received modified with or without immediate-release opioids were matched to those receiving immediate-release opioids only (1:1) using nearest neighbour propensity score matching with patient and clinical characteristics as covariates. This included total opioid dose received. In the matched cohorts, patients given modified-release opioids (n = 347) experienced a higher incidence of opioid-related adverse events overall, compared with those given immediate-release opioids only (20.5%, 71/347 vs. 12.7%, 44/347; difference in proportions 7.8% [95%CI 2.3–13.3%]). Modified-release opioid use was associated with an increased risk of harm when used for acute pain during hospitalisation after total hip or knee arthroplasty.  相似文献   
5.
Post-induction hypotension is common and associated with postoperative complications. We hypothesised that pneumatic leg compression reduces post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy. In this double-blind randomised study, patients were allocated randomly to the pneumatic leg compression group (n = 50) or control (n = 50). In the intervention group, pneumatic leg compression was initiated before induction of anaesthesia. In the control group, pneumatic leg compression was initiated 20 min after anaesthesia induction. The primary outcome was the incidence of post-induction hypotension in these groups. Post-induction hypotension was defined as systolic blood pressure < 90 mmHg during the first 20 min after induction. Haemodynamic variables and area under the curve of post-induction systolic blood pressure over time were assessed. Complications associated with pneumatic leg compression were recorded, including: peripheral neuropathy; compartment syndrome; extensive bullae beneath the leg sleeves; and pulmonary thromboembolism. The incidence of post-induction hypotension decreased in the pneumatic leg compression group compared with that in the control group; 5 (10%) vs. 29 (58%), respectively, p < 0.001. In the pneumatic leg compression group, the lowest systolic, diastolic and mean blood pressures 20 min after induction of anaesthesia were significantly greater than the control group. Pneumatic leg compression resulted in an increased area under the curve of systolic blood pressure in the first 20 min after induction, p = 0.001. There were no pneumatic leg compression-related complications. Pneumatic leg compression reduced post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy, suggesting that it is an effective and safe intervention to prevent post-induction hypotension among elderly patients undergoing general anaesthesia.  相似文献   
6.
Journal of Thrombosis and Thrombolysis - The decision by pulmonary embolism response teams (PERTs) to utilize anticoagulation (AC) with or without systemic thrombolysis (ST) or catheter-directed...  相似文献   
7.
Pituitary - Our aim was to investigate the changes in the composition of oral and gut microbiota in patients with newly diagnosed acromegaly and their relationship with IGF-1 levels. Oral and fecal...  相似文献   
8.
9.
Ergin  Nesrin  Kılıç  Bilge Betül  Ergin  Ahmet  Varlı  Sema 《Sleep & breathing》2022,26(3):1299-1307
Sleep and Breathing - The aim was to determine sleep quality and related factors including restless leg syndrome in the 6th year medical students and medical residents in Pamukkale University,...  相似文献   
10.
Inflammopharmacology - The inflammatory process is a biological response of the organism to remove injurious stimuli and initiate homeostasis. It has been recognized as a key player in the most...  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