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   1593547篇
  免费   133623篇
  国内免费   2565篇
耳鼻咽喉   21643篇
儿科学   52892篇
妇产科学   46270篇
基础医学   226289篇
口腔科学   47346篇
临床医学   140387篇
内科学   312670篇
皮肤病学   34094篇
神经病学   129432篇
特种医学   64730篇
外国民族医学   474篇
外科学   243609篇
综合类   39692篇
现状与发展   3篇
一般理论   547篇
预防医学   122297篇
眼科学   36333篇
药学   121145篇
  2篇
中国医学   2877篇
肿瘤学   87003篇
  2018年   14808篇
  2016年   12950篇
  2015年   15070篇
  2014年   20735篇
  2013年   31486篇
  2012年   42747篇
  2011年   44948篇
  2010年   26426篇
  2009年   25400篇
  2008年   43130篇
  2007年   45373篇
  2006年   46209篇
  2005年   44826篇
  2004年   44221篇
  2003年   42182篇
  2002年   41300篇
  2001年   75664篇
  2000年   78208篇
  1999年   66048篇
  1998年   16732篇
  1997年   15362篇
  1996年   15320篇
  1995年   15966篇
  1994年   15017篇
  1993年   14157篇
  1992年   55445篇
  1991年   53805篇
  1990年   52588篇
  1989年   50851篇
  1988年   47231篇
  1987年   46596篇
  1986年   44306篇
  1985年   42874篇
  1984年   32016篇
  1983年   27547篇
  1982年   16107篇
  1981年   14390篇
  1980年   13511篇
  1979年   30451篇
  1978年   21039篇
  1977年   17721篇
  1976年   16666篇
  1975年   17541篇
  1974年   21483篇
  1973年   20668篇
  1972年   18857篇
  1971年   17759篇
  1970年   16288篇
  1969年   15268篇
  1968年   13948篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
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   
3.
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.
6.
7.
Cyclotron-produced copper-64 radioisotope tracers offer the possibility to perform both diagnostic investigation by positron emission tomography (PET) and radiotherapy by a theranostic approach with bifunctional chelators. The versatile chemical properties of copper add to the importance of this isotope in medicinal investigation. [64Cu][Cu (ATSM)] has shown to be a viable candidate for imaging of tumor hypoxia; a critical tumor microenvironment characteristic that typically signifies tumor progression and resistance to chemo-radiotherapy. Various production and radiosynthesis methods of [64Cu][Cu (ATSM)] exist in labs, but usually involved non-standardized equipment with varying production qualities and may not be easily implemented in wider hospital settings. [64Cu][Cu (ATSM)] was synthesized on a modified GE TRACERlab FXN automated synthesis module. End-of-synthesis (EOS) molar activity of [64Cu][Cu (ATSM)] was 2.2–5.5 Ci/μmol (HPLC), 2.2–2.6 Ci/μmol (ATSM-titration), and 3.0–4.4 Ci/μmol (ICP-MS). Radiochemical purity was determined to be >99% based on radio-HPLC. The final product maintained radiochemical purity after 20 h. We demonstrated a simple and feasible process development and quality control protocols for automated cyclotron production and synthesis of [64Cu][Cu (ATSM)] based on commercially distributed standardized synthesis modules suitable for PET imaging and theranostic studies.  相似文献   
8.
9.
10.
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