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   1594592篇
  免费   133511篇
  国内免费   2533篇
耳鼻咽喉   21699篇
儿科学   52932篇
妇产科学   46328篇
基础医学   226455篇
口腔科学   47242篇
临床医学   140483篇
内科学   312600篇
皮肤病学   34085篇
神经病学   129597篇
特种医学   64891篇
外国民族医学   474篇
外科学   243755篇
综合类   39756篇
一般理论   548篇
预防医学   122497篇
眼科学   36318篇
药学   121065篇
  2篇
中国医学   2878篇
肿瘤学   87031篇
  2018年   14797篇
  2016年   12893篇
  2015年   15086篇
  2014年   20744篇
  2013年   31501篇
  2012年   42763篇
  2011年   44979篇
  2010年   26483篇
  2009年   25421篇
  2008年   43144篇
  2007年   45426篇
  2006年   46198篇
  2005年   44835篇
  2004年   44261篇
  2003年   42263篇
  2002年   41385篇
  2001年   75716篇
  2000年   78270篇
  1999年   66101篇
  1998年   16743篇
  1997年   15373篇
  1996年   15327篇
  1995年   15976篇
  1994年   15020篇
  1993年   14175篇
  1992年   55448篇
  1991年   53850篇
  1990年   52633篇
  1989年   50889篇
  1988年   47259篇
  1987年   46592篇
  1986年   44329篇
  1985年   42912篇
  1984年   32054篇
  1983年   27563篇
  1982年   16123篇
  1981年   14417篇
  1980年   13523篇
  1979年   30467篇
  1978年   21064篇
  1977年   17736篇
  1976年   16690篇
  1975年   17549篇
  1974年   21501篇
  1973年   20689篇
  1972年   18888篇
  1971年   17793篇
  1970年   16305篇
  1969年   15298篇
  1968年   13973篇
排序方式: 共有10000条查询结果,搜索用时 250 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