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   1916262篇
  免费   153520篇
  国内免费   5405篇
耳鼻咽喉   26254篇
儿科学   59719篇
妇产科学   54860篇
基础医学   270680篇
口腔科学   57700篇
临床医学   166513篇
内科学   377390篇
皮肤病学   41393篇
神经病学   152305篇
特种医学   76734篇
外国民族医学   549篇
外科学   295467篇
综合类   49183篇
现状与发展   4篇
一般理论   601篇
预防医学   137035篇
眼科学   44782篇
药学   147960篇
  7篇
中国医学   5116篇
肿瘤学   110935篇
  2018年   18861篇
  2016年   16112篇
  2015年   18756篇
  2014年   25838篇
  2013年   38058篇
  2012年   51705篇
  2011年   54059篇
  2010年   32088篇
  2009年   30588篇
  2008年   51371篇
  2007年   54410篇
  2006年   55045篇
  2005年   52971篇
  2004年   51839篇
  2003年   49587篇
  2002年   48377篇
  2001年   98596篇
  2000年   101547篇
  1999年   85370篇
  1998年   21072篇
  1997年   18880篇
  1996年   18408篇
  1995年   18830篇
  1994年   17558篇
  1993年   16492篇
  1992年   68620篇
  1991年   66200篇
  1990年   64418篇
  1989年   62655篇
  1988年   57823篇
  1987年   56783篇
  1986年   53728篇
  1985年   51621篇
  1984年   37842篇
  1983年   32263篇
  1982年   18342篇
  1981年   16227篇
  1980年   15194篇
  1979年   35073篇
  1978年   23914篇
  1977年   20253篇
  1976年   18592篇
  1975年   19794篇
  1974年   24096篇
  1973年   23142篇
  1972年   21363篇
  1971年   20208篇
  1970年   18533篇
  1969年   17497篇
  1968年   15962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.
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   
4.
杜玫洁  黄素芳  熊杰  储备 《护理学杂志》2022,27(10):110-113
以过渡期护理内涵为基础对文献进行干预措施内容提取,以干预时间点为标准对ICU转科患者家属迁移应激的过渡期护理措施进行综述,护理干预措施包括干预前准备、转科前干预、转科中干预、转科后干预,并总结护理干预效果评价,以期为临床护理人员开展相关实践提供具体参考,推进以家庭为中心的护理工作,改善临床护理质量。  相似文献   
5.
6.
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   
7.
The aim of this safety study in mice was to determine in vivo toxicity and biodistribution potential of a single and multiple doses of L-glutamic acid-g-p(HEMA) polymeric nanoparticles as a drug delivery system. The single dose did not cause any lethal effect, and its acute oral LD50 was >2.000 mg/kg body weight (bw). Multiple doses (25, 50, or 100 mg/kg bw) given over 28 days resulted in no significant differences in body and relative organ weights compared to control. These results are supported by biochemical and histological findings. Moreover, nanoparticle exposure did not result in statistically significant differences in micronucleus counts in bone marrow cells compared to control. Nanoparticle distribution was time-dependent, and they reached the organs and even bone marrow by hour 6, as established by ex vivo imaging with the IVIS® spectrum imaging system. In conclusion, L-glutamic acid-g-p(HEMA) polymeric nanoparticles appear biocompatible and have a potential use as a drug delivery system.KEY WORDS: biocompatibility, blood biochemistry, genotoxicity, histology, in vivo toxicity, micronucleus test, polymers  相似文献   
8.
9.
10.
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   
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