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   1652篇
  免费   344篇
  国内免费   777篇
  2024年   2篇
  2023年   33篇
  2022年   89篇
  2021年   83篇
  2020年   102篇
  2019年   78篇
  2018年   86篇
  2017年   103篇
  2016年   73篇
  2015年   94篇
  2014年   134篇
  2013年   197篇
  2012年   182篇
  2011年   185篇
  2010年   198篇
  2009年   146篇
  2008年   179篇
  2007年   169篇
  2006年   190篇
  2005年   108篇
  2004年   81篇
  2003年   54篇
  2002年   43篇
  2001年   22篇
  2000年   20篇
  1999年   7篇
  1998年   15篇
  1997年   6篇
  1996年   6篇
  1995年   4篇
  1994年   9篇
  1993年   6篇
  1992年   6篇
  1991年   3篇
  1989年   6篇
  1988年   2篇
  1987年   4篇
  1986年   2篇
  1985年   9篇
  1983年   2篇
  1981年   3篇
  1979年   2篇
  1974年   3篇
  1970年   2篇
  1965年   8篇
  1964年   4篇
  1963年   2篇
  1960年   1篇
  1959年   2篇
  1955年   1篇
排序方式: 共有2773条查询结果,搜索用时 15 毫秒
121.
The traditional Square of Opposition consists of four sentence types. Two are universal and two particular; two are affirmative and two negative. Examples, where ‘S’ and ‘P’ designate the subject and the predicate, are: ‘every S is P’, ‘no S is P’, ‘some S is P’ and ‘some S is not P’. Taking the usual sentences of the square of opposition, quantifying over their predicates exhibits non-standard sentence forms. These sentences may be combined into non-standard Squares of Opposition (an Octagon in this case), and they reveal a new relationship not found in the usual Square. Medieval logicians termed ‘disparatae’ pairs of sentences like ‘every S is some P’ and ‘some S is every P’, which are neither subaltern nor contrary, neither contradictory nor subcontrary. Walter Redmond has designed a special language L to express the logical form of these sentences in a precise way. I will use this language to show how Squares of Opposition, standard and non-standard, form a complex network of relations which bring to light the subtleties contained in this traditional doctrine.  相似文献   
122.
探讨正常高值血压昼夜节律与靶器官损害的相关性。入选正常高值血压者150例,其中杓型组72例,非杓型组78例,60例正常血压者为对照组。检测尿白蛋白排泄率(UAE)、颈动脉内膜中层厚度(IMT)和左心室重量指数(LVMI)。杓型组和非杓型组UAE、IMT、LVMI高于对照组(P<0.01)。非杓型组UAE、IMT、LVMI高于杓型组(P<0.05)。正常高值血压人群已出现靶器官损害,血压昼夜节律异常与早期靶器官损害密切相关。  相似文献   
123.
艰难梭菌相关性腹泻(CDAD)是重症患者非常重要的院内感染性疾病之一,常与广谱抗菌药物的广泛应用有关,其中肠道菌群失调是重要的因素之一。虽然艰难梭菌感染(CDI)仅占抗菌药物相关性腹泻中的10%~20%,但是目前CDAD的发生率呈明显升高趋势,且根据研究显示,重症患者CDAD的30天病死率已达36.7%。CDAD的临床...  相似文献   
124.
为比较替格瑞洛与氯吡格雷对急性ST段抬高型心肌梗死(STEMI)患者急诊经皮冠状动脉介入术(PCI)术后炎症因子的影响,将176例急性STEMI且行急诊PCI术的患者分为替格瑞洛组(A组)58例、氯吡格雷常规组(B组)58例、氯吡格雷强化组(C组)60例,分别测定术前、术后12小时、术后7天、术后1个月、术后3个月、6个月时炎症因子e反应蛋白(CRP)、白细胞介素-6(IL6)、髓过氧物酶(MPO)、可溶性CD40受体(sCD40L)的含量,比较3组患者各炎症因子在不同时间点有无统计学差异。结果显示c组和A组较B组明显降低(P〈0.05),有统计学意义,而A组较c组稍降低(P〉0.05),但两者无统计学意义。由此可见,替格瑞洛的抗炎作用较常规剂量氯吡格雷作用明显增强,和强化剂量氯吡格雷作用相仿。  相似文献   
125.
个性化契约作为组织中一种非标准化的工作安排,以往研究较多关注其对契约获得者的积极效应,相对忽视了对未获得者的消极影响。鉴于此,本研究基于公平理论,探讨了同事个性化契约对员工工作退缩行为的影响及其内部机理。结果发现:同事个性化契约会引发员工的工作退缩行为,员工的心理契约违背在此过程中起部分中介作用;此外,员工与组织间较高的社会交换关系会削弱同事个性化契约对员工心理契约违背的正向影响。  相似文献   
126.
Adolescence is critical for learning autonomous behavior; however, little research is available on the most appropriate balance of the emotional and behavioral dimensions of autonomy for psychosocial adjustment during this period. In this study we present a novel autonomy typology that combines both these aspects, which can be implemented as autonomy in decision-making and emotional separation. Specifically, examined age differences in emotional separation and autonomy in decision-making during adolescence. We also assessed differences in psychosocial adjustment associated with profiles of autonomy typology, sex, and age. The participants were 567 adolescents (296 males and 271 females), aged between 12 and 18 years (M?=?14.48; SD?=?1.69), recruited in Spanish high schools. Each participant filled out questionnaires on identity commitment, self-esteem, emotional separation and autonomy in decision-making. The results showed that the most advantageous autonomy profile is ‘autonomous in decisions’ (those showing low emotional separation combined with autonomous behavior in decisions) which was associated with higher levels of self-esteem and occupational and ideological identity commitment. In addition, we also concluded that the balance of autonomy affects adjustment throughout adolescence, although early adolescence may be an especially critical period.  相似文献   
127.

Background/Objective

Sexual double standard (SDS) has long been associated to several dimensions of sexual health. Therefore the assessment of SDS is relevant and requires self-reported measures with adequate psychometric properties. This study aims to adapt the Sexual Double Standard Scale (SDSS) into heterosexual Spanish population and examine its psychometric properties. Method: Using quota incidental sampling, we recruited a sample of 1,206 individuals (50% women), distributed across three groups based on their age (18-34, 35-49 and 50 years old and older). Results: We performed both, Exploratory Factor Analysis and Confirmatory Factor Analysis. An abridged version was yielded, consisting of 16 items distributed into two factors (Acceptance for sexual freedom and Acceptance for sexual shyness). A second-order factor structure was also adequate, which facilitates the use of a global index for SDS. Reliability, based on internal consistency and temporal stability was good for the factors. Evidence of validity is also shown and reported. Conclusions: This adapted version of the SDSS is reliable and valid. The importance for its use to estimate the prevalence of both traditional and modern forms of this phenomenon is discussed.  相似文献   
128.
The aim of this study was to explore whether children with and without learning difficulties use orthographic rules to write words. To study this, two types of tasks from the Early Grade Writing Assessment (EGWA) test were used: (1) a dictation task which included pseudowords with an implicit orthographic rule; and (2) a dictation task which included words with arbitrary, unregulated orthography. An initial sample of 1,447 students from grades 1 to 3 of elementary school was selected. The results showed that the variables task type and grade were significant when explaining the differences found between the groups. These findings are discussed from the perspective of the orthographic representations self-teaching hypothesis as related to the orthographic depth hypothesis, associated with the orthographic transparency of Spanish.  相似文献   
129.
采用学生感知教师支持行为问卷和中学生心理素质问卷,对西南地区两所中学7~12年级的824名在校中学生进行调查研究,探讨教师整体支持和不同类型支持与中学生学业成绩的关系及心理素质在其中的中介作用。结果发现:(1)教师整体支持与中学生心理素质、学业成绩间存在显著正相关;教师情感支持与中学生心理素质、学业成绩间存在显著正相关,教师学习支持、能力支持与中学生心理素质存在显著正相关,但与学业成绩相关均不显著;(2)控制性别和年龄后,心理素质在教师整体支持与学业成绩的关系中起完全中介作用;心理素质在教师情感支持与学业成绩关系中起部分中介作用,在教师学习支持与学业成绩、教师能力支持与学业成绩关系中均起完全中介作用。  相似文献   
130.
It is not clear whether multiple unrelated meanings inhibit or facilitate word recognition. Some studies have found a disadvantage for words having multiple meanings with respect to unambiguous words in lexical decision tasks (LDT), whereas several others have shown a facilitation for such words. In the present study, we argue that these inconsistent findings may be due to the approach employed to select ambiguous words across studies. To address this issue, we conducted three LDT experiments in which we varied the measure used to classify ambiguous and unambiguous words. The results suggest that multiple unrelated meanings facilitate word recognition. In addition, we observed that the approach employed to select ambiguous words may affect the pattern of experimental results. This evidence has relevant implications for theoretical accounts of ambiguous words processing and representation.  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