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   10555篇
  免费   668篇
  国内免费   414篇
耳鼻咽喉   223篇
儿科学   140篇
妇产科学   25篇
基础医学   2290篇
口腔科学   144篇
临床医学   759篇
内科学   753篇
皮肤病学   86篇
神经病学   2086篇
特种医学   992篇
外科学   294篇
综合类   873篇
预防医学   653篇
眼科学   234篇
药学   571篇
  2篇
中国医学   1350篇
肿瘤学   162篇
  2024年   68篇
  2023年   195篇
  2022年   386篇
  2021年   442篇
  2020年   333篇
  2019年   295篇
  2018年   290篇
  2017年   340篇
  2016年   346篇
  2015年   364篇
  2014年   551篇
  2013年   861篇
  2012年   533篇
  2011年   672篇
  2010年   492篇
  2009年   496篇
  2008年   539篇
  2007年   468篇
  2006年   447篇
  2005年   402篇
  2004年   352篇
  2003年   301篇
  2002年   279篇
  2001年   225篇
  2000年   194篇
  1999年   175篇
  1998年   161篇
  1997年   154篇
  1996年   138篇
  1995年   156篇
  1994年   140篇
  1993年   137篇
  1992年   93篇
  1991年   106篇
  1990年   61篇
  1989年   75篇
  1988年   56篇
  1987年   46篇
  1986年   33篇
  1985年   46篇
  1984年   34篇
  1983年   29篇
  1982年   23篇
  1981年   17篇
  1980年   20篇
  1979年   13篇
  1977年   12篇
  1976年   9篇
  1974年   8篇
  1973年   9篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
We have established the content and molecular species of immunoreactive β-endorphin (ir-β-END) and immunoreactive N-acetyl-endorphin (ir-Nac-END) in rat neurointermediate lobe by specific radioimmunoassay (RIA) and high-performance liquid chromatography after chronic administration of dopamine (DA) agonists and antagonists. The DA agonist, bromocriptine, reduces tissue levels of all major immunoreactive species, in particular the C-terminally shortened N-acetylated forms. The DA antagonist, haloperidol, proportionally increases all immunoreactive forms, except Nac-β-END1–27, thus altering the relative abundance of this species. These data indicate that DA is involved in the control of both tissue levels and processing of β-END-like peptides in the rat neurointermediate lobe.  相似文献   
92.
We used behavioral measures and functional magnetic resonance imaging (fMRI) to study the effects of parametrically varied task-irrelevant pitch changes in attended sounds on loudness-discrimination performance and brain activity in cortical surface maps. Ten subjects discriminated tone loudness in sequences that also included infrequent task-irrelevant pitch changes. Consistent with results of previous studies, the task-irrelevant pitch changes impaired performance in the loudness discrimination task. Auditory stimulation, attention-enhanced processing of sounds and motor responding during the loudness discrimination task activated supratemporal (auditory cortex) and inferior parietal areas bilaterally and left-hemisphere (contralateral to the hand used for responding) motor areas. Large pitch changes were associated with right hemisphere supratemporal activations as well as widespread bilateral activations in the frontal lobe and along the intraparietal sulcus. Loudness discrimination and distracting pitch changes activated common areas in the right supratemporal gyrus, left medial frontal cortex, left precentral gyrus, and left inferior parietal cortex.  相似文献   
93.
The error negativity (Ne/ERN) and error positivity (Pe) are two components of the event-related brain potential (ERP) that are associated with action monitoring and error detection. To investigate the relation between error processing and conscious self-monitoring of behavior, the present experiment examined whether an Ne and Pe are observed after response errors of which participants are unaware. Ne and Pe measures, behavioral accuracy, and trial-to-trial subjective accuracy judgments were obtained from participants performing an antisaccade task, which elicits many unperceived, incorrect reflex-like saccades. Consistent with previous research, subjectively unperceived saccade errors were almost always immediately corrected, and were associated with faster correction times and smaller saccade sizes than perceived errors. Importantly, irrespective of whether the participant was aware of the error or not, erroneous saccades were followed by a sizable Ne. In contrast, the Pe was much more pronounced for perceived than for unperceived errors. Unperceived errors were characterized by the absence of posterror slowing. These and other results are consistent with the view that the Ne and Pe reflect the activity of two separate error monitoring processes, of which only the later process, reflected by the Pe, is associated with conscious error recognition and remedial action.  相似文献   
94.
Summary This short paper summarizes the basic concept and the technology of a new computed radiographic system which uses an energy-storage phosphorus panel called Imaging Plate as an image sensor. The Imaging Plate can be used to obtain radiographs in exactly the same way as the screen-film combination is used in conventional radiography. The system eliminates the drawbacks of conventional screen-film radiography by combining digital image processing and digitization of the x-ray energy pattern utilizing scanning laser stimulated luminescence.The major part of this paper was originally delivered at the 1984 AAPM Annual Summer School which was held on July 22–27 at University of Notre Dame, USA. Modified for the publication in the Neurosurgical Review.  相似文献   
95.
通过查阅历代本草、医籍、方书并结合近现代文献资料,笔者对杜仲药材的名称、基原、产地、品质评价、采收加工、炮制历史沿革及产地变迁情况进行了系统梳理及考证,以期为含杜仲的经典名方开发提供参考依据。经考证可知,历代本草均以杜仲为正名,基原为杜仲科植物杜仲Eucommia ulmoides的干燥树皮,古今一致;杜仲最早的产地为河南、山西、陕西、四川一带,自明代以来产地扩展至全国大部分地区,且推崇四川、陕西、重庆、贵州、湖北等地为杜仲的道地产区;近代以来总结其品质以皮厚、块大、粗皮刮净、断面多丝、内表面色暗紫为佳;杜仲的古代炮制加工方法主要有去粗皮切制生用和加酥蜜、姜汁、盐水、酒等辅料炮制,近现代以来炮制方法日趋简化,沿用的炮制方法主要为净制后切制生用、盐炙,建议挖掘不同杜仲炮制品的现代科学内涵,通过标准恢复传统主流炮制方法。基于宋代陈自明的三痹汤中杜仲“去皮,切,姜汁炒”的要求,根据考证结果,建议使用姜杜仲,即参考2020年版《中华人民共和国药典》炒法,以姜汁为辅料进行炮制后入药。  相似文献   
96.
With an increasing prevalence of diabetes worldwide, effective dietary strategies for blood glucose control are crucial. As carbohydrates make up approximately 50% of the diet, it is neither practical nor advisable to avoid them altogether. Most of the carbohydrate in the diet is derived from starch, found in potatoes, pasta, rice and bread. These foods are often processed in some way before consumption, yet little is known about the effects processing, such as chilling and reheating, has on the glycaemic response, particularly when the food is consumed in the context of a mixed meal. This article introduces the SPUD project, a BBSRC DRINC‐funded initiative. Taking the potato as the model carbohydrate, this project will investigate, via in vitro and in vivo studies, the effects of domestic food processing techniques on the glycaemic response. A final study, utilising intrinsically labelled potato and a dual stable isotope methodology, will model glucose flux data to determine the underlying mechanisms of action.  相似文献   
97.
目的:探索一种连续在位测定固体制剂溶出度的新方法和新理论。方法:应用芘丁酸光纤化学传感器和计算机联用在线技术及中国药典(1995版)规定的紫外分光光度法(UV)分别测定氧氟沙星片剂的体外溶出度。结果:在药典规定的测定浓度范围内有良好的线性,相关系数0.9980。方法的日内、日间精密度(RSD)分别为1.18%和1.56%,当信噪比为3时检测限为0.56μg/ml。用中国药典(1995版)规定的紫外分光光度法作对照并进行评价,P>0.05,显示两种方法所得结果无显著性差异。结论:本法改变传统的取样分析模式,实现了响应快速、准确、灵敏的过程分析。  相似文献   
98.
BackgroundEntrustable Professional Activities (EPAs) contain narrative ‘entrustment roadmaps’ designed to describe specific behaviors associated with different entrustment levels. However, these roadmaps were created using expert committee consensus, with little data available for guidance. Analysis of actual EPA assessment narrative comments using natural language processing may enhance our understanding of resident entrustment in actual practice.MethodsAll text comments associated with EPA microassessments at a single institution were combined. EPA—entrustment level pairs (e.g. Gallbladder Disease—Level 1) were identified as documents. Latent Dirichlet Allocation (LDA), a common machine learning algorithm, was used to identify latent topics in the documents associated with a single EPA. These topics were then reviewed for interpretability by human raters.ResultsOver 18 months, 1015 faculty EPA microassessments were collected from 64 faculty for 80 residents. LDA analysis identified topics that mapped 1:1 to EPA entrustment levels (Gammas >0.99). These LDA topics appeared to trend coherently with entrustment levels (words demonstrating high entrustment were consistently found in high entrustment topics, word demonstrating low entrustment were found in low entrustment topics).ConclusionsLDA is capable of identifying topics relevant to progressive surgical entrustment and autonomy in EPA comments. These topics provide insight into key behaviors that drive different level of resident autonomy and may allow for data-driven revision of EPA entrustment maps.  相似文献   
99.
姜丽  李成华  薛长松 《中草药》2023,54(17):5786-5795
科学合理的中药药性研究方法是中医药药性科学内涵研究的基础和客观要求。在既往创建的“单味药药性成因假说”理论指导下,在国内外首次创建“单味药药性形成演变分类范式模块”研究方法。运用此方法,在利用现代药效物质基础研究成果解析淫羊藿四气药性合理性的基础上,在中医学理论语境下,分析单味药淫羊藿四气药性历史形成、演变过程及影响因素,并将研究结果纳入模块类别单元分类。为建立系统、科学合理的中药药性研究方法与手段,提供了新思路。  相似文献   
100.
Altered sensory functioning is often observed in individuals with SHANK3 related Phelan-McDermid syndrome (PMS). Compared to typically developing individuals and individuals with an autism spectrum disorder, it has been suggested that there are distinctive features of sensory functioning in PMS. More hyporeactivity symptoms and less hyperreactivity and sensory seeking behaviour are seen, particularly in the auditory domain. Hypersensitivity to touch, possible overheating or turning red easily and reduced pain response are often seen.In this paper the current literature on sensory functioning in PMS is reviewed and recommendations for caregivers, based on consensus within the European PMS consortium, are given.  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