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   55851篇
  免费   3731篇
  国内免费   1917篇
耳鼻咽喉   718篇
儿科学   1348篇
妇产科学   744篇
基础医学   4851篇
口腔科学   863篇
临床医学   5018篇
内科学   7185篇
皮肤病学   1971篇
神经病学   3486篇
特种医学   1256篇
外国民族医学   8篇
外科学   3072篇
综合类   7282篇
现状与发展   3篇
预防医学   5857篇
眼科学   747篇
药学   10943篇
  31篇
中国医学   3300篇
肿瘤学   2816篇
  2023年   648篇
  2022年   944篇
  2021年   1771篇
  2020年   1724篇
  2019年   1655篇
  2018年   1717篇
  2017年   1789篇
  2016年   1778篇
  2015年   1782篇
  2014年   3362篇
  2013年   4249篇
  2012年   3350篇
  2011年   3615篇
  2010年   2872篇
  2009年   2767篇
  2008年   2809篇
  2007年   2903篇
  2006年   2420篇
  2005年   2210篇
  2004年   1846篇
  2003年   1623篇
  2002年   1306篇
  2001年   1210篇
  2000年   1034篇
  1999年   967篇
  1998年   744篇
  1997年   758篇
  1996年   671篇
  1995年   707篇
  1994年   646篇
  1993年   551篇
  1992年   560篇
  1991年   495篇
  1990年   442篇
  1989年   435篇
  1988年   425篇
  1987年   355篇
  1986年   284篇
  1985年   356篇
  1984年   279篇
  1983年   237篇
  1982年   251篇
  1981年   174篇
  1980年   167篇
  1979年   111篇
  1978年   106篇
  1977年   83篇
  1976年   79篇
  1975年   54篇
  1973年   35篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Amiodarone is the most potent antiarrhythmic drug available and is commonly prescribed to treat and prevent not only life-threatening ventricular arrhythmias but also atrial fibrillation (AF). The latest European Society of Cardiology AF guidelines state that amiodarone is recommended for long-term rhythm control in all AF patients but that other antiarrhythmic drugs should be considered first whenever possible, due to its extracardiac toxicity. In patients without significant or with only minimal structural heart disease, amiodarone is not listed as a possibility in their therapeutic scheme. Still, amiodarone is widely and liberally used, and is the most prescribed antiarrhythmic drug for patients with AF despite its high toxicity profile. Non-cardiovascular death was more frequent with amiodarone treatment than with a rate control strategy in AFFIRM, while meta-analyses suggest an association between amiodarone use in patients without structural heart disease and increased non-cardiovascular mortality. Severe or even fatal outcomes due to amiodarone may occur years after treatment initiation and are often not acknowledged by the prescribing physician, who may no longer be following the patient. The lack of widely accepted diagnostic criteria and symptom definitions may lead to underestimation of the incidence of severe side effects and of its toxicity. Unlike the underestimated risk of toxicity with amiodarone, severe complications associated with catheter ablation are usually directly ascribed to the treatment even by non-medical personnel, possibly resulting in overestimation of risks. This brief review will address the issue of amiodarone overuse and the frequent underestimation of its toxicity, while suggesting scenarios in which its use is entirely reasonable, and compare it with catheter ablation.  相似文献   
2.
轻度认知障碍(Mild cognition impairment, MCI)是尚未达到阿尔兹海默病(Alzheimer’s disease, AD)的诊断标准且可逆转为正常脑老化状态的最佳窗口期。情志异常、肝失疏泄(肝失疏泄日久致肝郁)已被证实为MCI的重要情志病机,且“长期负性情绪积累肝失疏泄致衰加速脑老化”的科学假说已在本课题组前期研究中得到初步证实,疏肝法干预肝郁型MCI患者疗效显著,但以上作用机制尚未得到完全阐述。因此本研究系统总结了中医学对MCI的认识,长期情绪不调肝失疏泄对MCI的影响及可能机制,疏肝解郁方药及其成分改善肝郁型MCI的可行性,并提出使用无束缚性设计的眼动技术以探索疏肝法改善肝郁型MCI的可行性,为MCI的中医药干预及其神经机制探讨提供新思路,为中医情志衰老学说增添新内涵。  相似文献   
3.
Age-related cognitive decline is the major cause of concern due to its 70% more incidence than dementia cases worldwide. Moreover, aging is also the major risk factor of Alzheimer's disease (AD), associated with progressive memory loss. Approx. 13 million people will have Alzheimer-related memory decline by 2050. Learning and memory is the fundamental process of brain functions. However, the mechanism for the same is still under investigation. Thus, it is critical to understand the process of memory consolidation in the brain and extrapolate its understanding to the memory decline mechanism. Research on learning and memory has identified several molecular signatures such as Protein kinase M zeta (PKMζ), Calcium/calmodulin-dependent protein kinase II (CaMKII), Brain-derived neurotrophic factor (BDNF), cAMP-response element binding protein (CREB) and Activity-regulated cytoskeleton-associated protein (Arc) crucial for the maintenance and stabilization of long-term memory in the brain. Interestingly, memory decline in AD has also been linked to the abnormality in expressing these memory-related molecular signatures. Hence, in the present consolidated review, we explored the role of these memory-related molecular signatures in long-term memory consolidation. Additionally, the effect of amyloid-beta toxicity on these molecular signatures is discussed in detail.  相似文献   
4.
Take the lead     
《Survey of ophthalmology》2023,68(5):1006-1010
A 23-year-old previously healthy woman presented with headache, generalized seizures, ataxia, encephalopathy, abdominal pain, nausea, and vomiting culminating in a 40-pound weight loss. A contrasted magnetic resonance imaging scan of the brain showed T2/FLAIR hyperintensities in the sulci of the occipital and parietal lobes, a punctate focus of restricted diffusion along the inferior aspect of the left caudate head and an empty sella. A lumbar puncture showed an opening pressure of 55 cm H2O, and kidney, ureter, and bladder X ray showed a radiopaque particle in the colon. Serum lead level was 85 mcg/dL (< 3.5). Blood smear showed foreign bodies identified as lead particles in the blood with basophilic stippling of RBCs. She was treated with chelation therapy and bowel irrigation and eventually recovered. Further investigation indicated that she was being slowly poisoned by her husband, a chiropractor who had access to lead.  相似文献   
5.
The performance of enzyme linked immunosorbent assays (EAST) for identifying six indoor allergens was evaluated using skin prick test (SPT) as reference tests in 154 children with allergic rhinitis. Sensitivity of EAST ranged from 9% (cat) to 54% (HDM) with specificity of 74%(cockroach) to 100% (cat) with an agreement ranged from 58 to 86%. Cut off values ?> ?0.35 kU/L showed best sensitivity and specificity. Our findings agree with extant literature which suggests that the ability of EAST to determine the precipitating allergen is moderate. Assays for definitively identifying the inhalant allergen are currently not available.  相似文献   
6.
Rapid industrial and technological development has impacted ecosystem homeostasis strongly. Arsenic is one of the most detrimental environmental toxins and its management with chelating agents remains a matter of concern due to associated adverse effects. Thus, safer and more effective alternative therapy is required to manage arsenic toxicity. Based on existing evidence, native and indigenous plant-based active biomolecules appear as a promising strategy to mitigate arsenic-induced toxicity with an acceptable safety profile. In this regard, various phytochemicals (flavonoids and stilbenoids) are considered important classes of polyphenolic compounds with antioxidant and chelation effects, which may facilitate the removal of arsenic from the body more effectively and safely with regard to conventional approaches. This review presents an overview of conventional chelating agents and the potential role of flavonoids and stilbenoids in ameliorating arsenic toxicity. This report may provide a roadmap for identifying novel prophylactic/therapeutic strategies for managing arsenic toxicity.  相似文献   
7.
摘要:目的以分子测序为参考 ,评估形态学、基质辅助激光解吸电离飞行时间质谱对毛霉目真菌的鉴定能力,分析毛霉目真菌对两性霉素B、泊沙康唑的体外药敏特点。方法收集 2018年1月-2022年2月广东省人民医院25例毛霉病住院患者标 本,进行镜检并对培养的茵落行形态学鉴定、质谱鉴定、分子测序和体外药敏试验。结果KOH 湿片法阳性率(76%)高于革兰染色法(32%),差异有统计学意义(P<0.05);形态学鉴定可将68%的菌株鉴定到属水平,3株鉴定错误,2株无法鉴定;将所 有菌株进行质谱鉴定,单用IVD和RUO数据库鉴定率分别为56%和44%,两库联合可将鉴定率提高为64%。毛霉目真菌对两性霉素B的抑制50%菌株生长的最小抑菌浓度(MIC3o)为1μg/mL,根霉属相比其他属对两性霉素B表现出较高的MIC 值,其中2株MIC>32 μg/mL,另2株MIC为8 μg/mL;根霉属对泊沙康唑的MICso为0.5 μg/mL,横梗霉属MICgo为4 μg/ mL,小克银汉霉属MICg0为2 μg/mL,有部分菌株表现出较低MIC值,同样亦有部分菌株对泊沙康唑表现出较高的MIC 值。结论 将传统镜检、培养与质谱技术和分子技术相结合,尽量将毛霉目真菌准确鉴定到种,并积极开展毛霉体外药敏试验,可为临床治疗提供参考依据。  相似文献   
8.
9.
ObjectivesTo determine which nursing home (NH) resident-level admission characteristics are associated with potentially preventable emergency department (PPED) transfers.DesignWe conducted a population-level retrospective cohort study on NH resident data collected using the Resident Assessment Instrument-Minimum Data Set Version 2.0 and linked to the National Ambulatory Care Reporting System for ED transfers.SettingWe used all NH resident admission assessments from January 1, 2017, to December 31, 2018, in Ontario.ParticipantsThe cohort included the admission assessment of 56,433 NH residents.MethodsPPED transfers were defined based on the International Classification of Disease, Version 10 (Canadian) We used logistic regression with 10-fold cross-validation and computed average marginal effects to identify the association between resident characteristics at NH admission and PPED transfers within 92 days after admission.ResultsOverall, 6.2% of residents had at least 1 PPED transfer within 92 days of NH admission. After adjustment, variables that had a prevalence of 10% or more that were associated with a 1% or more absolute increase in the risk of a PPED transfer included polypharmacy [of cohort (OC) 84.4%, risk difference (RD) 2.0%], congestive heart failure (OC 29.0%, RD 3.0%), and renal failure (OC 11.6%, RD 1.2%). Female sex (OC 63.2%, RD -1.3%), a do not hospitalize directive (OC 24.4%, RD -2.6%), change in mood (OC 66.9%, RD -1.2%), and Alzheimer's or dementia (OC 62.1%, RD -1.2%) were more than 10% prevalent and associated with a 1% or more absolute decrease in the risk of a PPED.Conclusions and ImplicationsThough many routinely collected resident characteristics were associated with a PPED transfer, the absence of sufficiently discriminating characteristics suggests that emergency department visits by NH residents are multifactorial and difficult to predict. Future studies should assess the clinical utility of risk factor identification to prevent transfers.  相似文献   
10.
The work-up of melanocytic tumors has undergone significant changes in the last years following the exponential growth of molecular assays. For the practicing pathologist it is often difficult to sort through the myriad of different tests available currently for clinical use. The molecular tests used in melanocytic pathology can be broadly divided into 4 categories: (i) Tests useful in the differential diagnosis of nevus versus melanoma (primarily used as an aid in the diagnosis of histologically ambiguous melanocytic tumors), (ii) Tests that predict prognosis in melanoma, (iii) Tests useful in the classification of melanocytic tumors and (iv) Tests that predict response to systemic therapy in melanoma. This review will present an updated overview of major ancillary tests used in clinical practice.  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