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   28021篇
  免费   2107篇
  国内免费   616篇
耳鼻咽喉   88篇
儿科学   310篇
妇产科学   272篇
基础医学   1626篇
口腔科学   237篇
临床医学   2007篇
内科学   3796篇
皮肤病学   182篇
神经病学   2211篇
特种医学   228篇
外国民族医学   1篇
外科学   671篇
综合类   3706篇
现状与发展   1篇
一般理论   4篇
预防医学   3510篇
眼科学   388篇
药学   10052篇
  13篇
中国医学   732篇
肿瘤学   709篇
  2024年   47篇
  2023年   438篇
  2022年   642篇
  2021年   1013篇
  2020年   986篇
  2019年   1206篇
  2018年   1149篇
  2017年   1201篇
  2016年   1032篇
  2015年   966篇
  2014年   1943篇
  2013年   3546篇
  2012年   1770篇
  2011年   1763篇
  2010年   1524篇
  2009年   1208篇
  2008年   1141篇
  2007年   1109篇
  2006年   1011篇
  2005年   905篇
  2004年   680篇
  2003年   608篇
  2002年   488篇
  2001年   511篇
  2000年   420篇
  1999年   363篇
  1998年   321篇
  1997年   270篇
  1996年   201篇
  1995年   190篇
  1994年   165篇
  1993年   167篇
  1992年   209篇
  1991年   207篇
  1990年   147篇
  1989年   122篇
  1988年   98篇
  1987年   94篇
  1986年   90篇
  1985年   141篇
  1984年   126篇
  1983年   95篇
  1982年   88篇
  1981年   69篇
  1980年   57篇
  1979年   44篇
  1978年   47篇
  1977年   42篇
  1976年   28篇
  1974年   21篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
This paper describes country-wide special measures undertaken for interventional radiology staff during the current coronavirus disease 2019 (COVID-19) pandemic. Although each interventional radiology service around the world faces unique challenges, the principles outlined in this article will be useful when designing or strengthening individual practices and integrating them within wider hospital and national measures. Moving beyond the current outbreak, these measures will be useful for any future infectious diseases which are likely to arise.  相似文献   
8.
ABSTRACT

Although communication about sexuality is a significant pathway through which peers influence adolescent sexual development, little research has examined the role of peer networks in the use of sexualized media. We applied a social network approach to assess the role of close peers in adolescent pornography use and sexting in a sample of Croatian high school students. Sexual conversation networks’ characteristics did not correlate with pornography use. In contrast, sexting was associated with the proportion of same gender peers, the proportion of older peers and the proportion of sexually experienced peers in the network – pointing to the role of peer influence. Participants’ gender did not moderate these associations. Specific mechanisms underlying the observed associations and the role of peer selection remain important tasks for future research.  相似文献   
9.
Abstract

Gaining a better grasp on factors related to changes in alcohol use is of particular interest for clinicians. Past research has highlighted a negative link between future time perspective (i.e. a disposition guiding how individuals consider and act regarding their future) and alcohol misuse. However, much remains at stake in the understanding of this association. The objective of this research was to explore bidirectional relationships between future time perspective and severity of alcohol-related problems, in a clinical setting. The sample includes 79 patients followed up in an outpatient alcohol treatment centre. Two measurement times were planned: at entry into care and 6 months later. Multiple linear regression analyses were carried out, controlling for sociodemographic variables. We found that baseline future time perspective predicted level of alcohol-related problems after 6 months in treatment, even when effects of baseline alcohol-related problems and sociodemographic variables were controlled. This study shows that the way patients see and position themselves regarding their future can affect level of alcohol-related problems. It may be useful for clinicians to identify patients with low future time perspective to offer tailored interventions and consider this dimension as a resource for change.  相似文献   
10.
《Brain stimulation》2022,15(2):337-351
BackgroundAbnormalities in frontoparietal network (FPN) were observed in many neuropsychiatric diseases including substance use disorders. A growing number of studies are using dual-site-tACS with frontoparietal synchronization to engage this network. However, a computational pathway to inform and optimize parameter space for frontoparietal synchronization is still lacking. In this case study, in a group of participants with methamphetamine use disorders, we proposed a computational pathway to extract optimal electrode montage while accounting for stimulation intensity using structural and functional MRI.MethodsSixty methamphetamine users completed an fMRI drug cue-reactivity task. Four main steps were taken to define electrode montage and adjust stimulation intensity using 4x1 high-definition (HD) electrodes for a dual-site-tACS; (1) Frontal seed was defined based on the maximum electric fields (EF) predicted by simulation of HD montage over DLPFC (F3/F4 in EEG 10–10), (2) frontal seed-to-whole brain context-dependent correlation was calculated to determine connected regions to frontal seeds, (3) center of connected cluster in parietal cortex was selected as a location for placing the second set of HD electrodes to shape the informed montage, (4) individualized head models were used to determine optimal stimulation intensity considering underlying brain structure. The informed montage was compared to montages with large electrodes and classic frontoparietal HD montages (F3-P3/F4-P4) in terms of tACS-induced EF and ROI-to-ROI task-based/resting-state connectivity.ResultsCompared to the large electrodes, HD frontoparietal montages allow for a finer control of the spatial peak fields in the main nodes of the FPN at the cost of lower maximum EF (large-pad/HD: max EF[V/m] = 0.37/0.11, number of cortical sub-regions that EF exceeds 50% of the max = 77/13). For defining stimulation targets based on EF patterns, using group-level head models compared to a single standard head model results in comparable but significantly different seed locations (6.43 mm Euclidean distance between the locations of the frontal maximum EF in standard-space). As expected, significant task-based/resting-state connections were only found between frontal-parietal locations in the informed montage. Cue-induced craving score was correlated with frontoparietal connectivity only in the informed montage (r = ?0.24). Stimulation intensity in the informed montage, and not in the classic HD montage, needs 40% reduction in the parietal site to reduce the disparity in EF between stimulation sites.ConclusionThis study provides some empirical insights to montage and dose selection in dual-site-tACS using individual brain structures and functions and proposes a computational pathway to use head models and functional MRI to define (1) optimum electrode montage for targeting FPN in a context of interest (drug-cue-reactivity) and (2) proper transcranial stimulation intensity.  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