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   3621篇
  免费   57篇
  国内免费   7篇
教育   2763篇
科学研究   302篇
各国文化   51篇
体育   250篇
综合类   12篇
文化理论   59篇
信息传播   248篇
  2023年   21篇
  2022年   47篇
  2021年   71篇
  2020年   107篇
  2019年   171篇
  2018年   225篇
  2017年   211篇
  2016年   175篇
  2015年   108篇
  2014年   144篇
  2013年   624篇
  2012年   140篇
  2011年   125篇
  2010年   132篇
  2009年   102篇
  2008年   93篇
  2007年   94篇
  2006年   88篇
  2005年   108篇
  2004年   104篇
  2003年   126篇
  2002年   93篇
  2001年   84篇
  2000年   53篇
  1999年   39篇
  1998年   22篇
  1997年   17篇
  1996年   19篇
  1995年   24篇
  1994年   14篇
  1993年   10篇
  1992年   11篇
  1991年   23篇
  1990年   14篇
  1989年   21篇
  1988年   9篇
  1987年   8篇
  1986年   11篇
  1985年   12篇
  1984年   7篇
  1982年   10篇
  1981年   13篇
  1980年   10篇
  1979年   9篇
  1978年   9篇
  1977年   10篇
  1974年   10篇
  1973年   8篇
  1966年   6篇
  1963年   6篇
排序方式: 共有3685条查询结果,搜索用时 15 毫秒
71.
Trajectories of adjustment were examined in a sample of street-involved youth across a 1-year period. Participants (N = 113; Mage = 14.18 years; 80.5% male, 91% non-White) were recruited in three Brazilian cities. Interviews conducted at three time points included six measures of physical and psychological adjustment. Unconditional growth models revealed linear declines over time (i.e., improved adjustment) on three indicators: health symptoms, sexual risk behaviors, and negative affect. There were no linear changes in drug use, positive affect, or life satisfaction. Conditional growth models revealed few significant effects for age or gender, but ratings of stressful life events moderated longitudinal changes in health symptoms, drug use, and negative affect. Implications for practice, policy, and theory are discussed.  相似文献   
72.
Neuroanatomy education is a challenging field which could benefit from modern innovations, such as augmented reality (AR) applications. This study investigates the differences on test scores, cognitive load, and motivation after neuroanatomy learning using AR applications or using cross-sections of the brain. Prior to two practical assignments, a pretest (extended matching questions, double-choice questions and a test on cross-sectional anatomy) and a mental rotation test (MRT) were completed. Sex and MRT scores were used to stratify students over the two groups. The two practical assignments were designed to study (1) general brain anatomy and (2) subcortical structures. Subsequently, participants completed a posttest similar to the pretest and a motivational questionnaire. Finally, a focus group interview was conducted to appraise participants’ perceptions. Medical and biomedical students (n = 31); 19 males (61.3%) and 12 females (38.7%), mean age 19.2 ± 1.7 years participated in this experiment. Students who worked with cross-sections (n = 16) showed significantly more improvement on test scores than students who worked with GreyMapp-AR (P = 0.035) (n = 15). Further analysis showed that this difference was primarily caused by significant improvement on the cross-sectional questions. Students in the cross-section group, moreover, experienced a significantly higher germane (P = 0.009) and extraneous cognitive load (P = 0.016) than students in the GreyMapp-AR group. No significant differences were found in motivational scores. To conclude, this study suggests that AR applications can play a role in future anatomy education as an add-on educational tool, especially in learning three-dimensional relations of anatomical structures.  相似文献   
73.
Abstract

Rowers sit on a seat that slides relative to the boat/ergometer. If a rower lifts him or herself from this sliding seat at any time, the seat will move away from under them and the rowing action is disrupted. From a mechanical perspective, it is clear that the need for the rower to remain in contact with the sliding seat at all times imposes position-dependent constraints on the forces exerted at the oar handle and the footstretcher. Here we investigate if the mechanical power output during rowing, which is strongly related to these forces, might be improved if the contact with the sliding seat was of no concern to the rower. In particular, we examine if elimination of these constraints by strapping the rower to the sliding seat leads to an increase in performance during the start on a standard rowing ergometer. Eleven well-trained female rowers performed 5-stroke starts in normal and strapped conditions. Handle force, vertical seat force, footstretcher force, and handle kinematics were recorded, from which mechanical power and work output were calculated. Most of the relevant mechanical variables differed significantly between the normal and strapped conditions. Most importantly, mechanical power output (averaged over the 5-stroke start) in the strapped condition was 12% higher than in the normal condition. We conclude that strapping a rower's pelvis to the sliding seat allows more vigorous execution of the stroke phases, resulting in a substantial improvement in performance during the start of ergometer rowing.  相似文献   
74.
ABSTRACT

This study aimed to investigate the effects of different training modalities on the soluble Klotho (S-Klotho) plasma levels in sedentary middle-aged adults. A total of 74 middle-aged adults (53.4 ± 5.0 years old; 52.7% women) were enrolled in the FIT-AGEING study. We conducted a 12-week randomised controlled trial. The participants were randomly assigned to 4 different groups: (i) a control group (no exercise), (ii) a physical activity recommendation from the World Health Organization group (PAR), (iii) a high intensity interval training group (HIIT), and (iv) a high intensity interval training group adding whole-body electromyostimulation training group (HIIT-EMS). S-Klotho plasma levels, anthropometric measurements, and body composition variables were measured before and after the intervention programme. All exercise training modalities induced an increase in the S-Klotho plasma levels (all P ≤ 0.019) without statistical differences between them (all P ≥ 0.696). We found a positive association between changes in lean mass index and changes in the S-Klotho plasma levels, whereas a negative association was reported between changes in fat mass outcomes and changes in the S-Klotho plasma levels after our intervention study. In conclusion, our results suggest that the link between exercise training and the increase in S-Klotho plasma levels could be mediated by a decrease of fat mass and an increase of lean mass.  相似文献   
75.
Through the analysis of survey and interview data, we investigated the attitudes and perceptions of 32 multilingual teachers of Spanish in Belize, a code-switching (CS) context where Spanish is in intense contact with English and Belizean Kriol. More specifically, we examined teachers’ and students’ attitudes toward Spanish and CS and teachers’ perceptions vis-à-vis students’ attitudes toward Spanish instruction. The study revealed that whereas some teachers held negative views of Northern Belizean Spanish, they did not markedly perceive standard Spanish as “better” than the local variety of Belizean Spanish. The analysis also showed that most teachers had a positive predisposition to the use of CS as a pedagogical tool in their classrooms, a finding that suggests that ultra-normative attitudes toward Spanish varieties are not prevalent among these educators. In view of students’ attitudes, teachers concurred that students had overwhelmingly negative attitudes toward standard Spanish, in line with previous findings. We argue that educational reforms and status-planning efforts are vital to destigmatize Spanish and to promote its maintenance alongside Belizean Kriol and English.  相似文献   
76.
Twenty‐three preschool‐age children, 3;6 (years; months) to 4;1, were videotaped separately with their mothers and fathers while each mother and father read a different unfamiliar storybook to them. The text from the unfamiliar storybooks was parsed and coded into story grammar elements and all parental extratextual utterances were transcribed and coded for (1) their relationship to the story grammar elements found within the storybook, and (2) the natural strategies parents used to direct their children's attention to these elements. Children's overall exposure to story grammar elements during book reading was also explored for its relationship to their language abilities. Results indicated that parents focused significantly more on the resolution, attempt, and consequence compared to the initiating event and plan, and most frequently used the text and pictures as strategies for recruiting their children's attention to the story grammar elements within the book. In addition, the frequency of parental utterances related to story grammar elements was negatively correlated with children's language abilities. This study did not examine the complexity or depth of parental utterances related to story grammar elements. These findings provide initial evidence that children may derive their understanding of story grammar at least in part through their parents' extratextual discussions during parent–child book reading.  相似文献   
77.
The authors voice teachers' perceptions of their interpersonal experiences with students in both positive and problematic relationships. Interview data from 28 teachers were examined by coding utterances on teacher and student interactions. Results indicate that teachers defined the quality of the relationship mostly by the level of communion (friendly vs. hostile), instead of by the level of agency (in control vs. powerless). Analyses of mentioned teacher and student behavior show a friendly interactional pattern for positive relationships and a hostile pattern for problematic ones. In teachers' perceptions, positive and problematic relationships also differed in context where encounters take place and topic of talk. Contrary to interactions in problematic relationships, encounters in positive relationships were mostly situated outside the classroom context and conversations during these encounters covered a wide range of topics. Implications for teacher education programs are discussed.  相似文献   
78.
According to Healthy People (2011), in order to understand the health concerns of the Lesbian, Gay, Bisexual, and Transgender (LGBT), the oppression and discrimination that they have faced must be scrutinized. Among the many issues they face, their estrangement experiences are one of the most understudied. However, little is known about how it is experienced by the gay elderly population, hence, this investigation. This grounded theory purports to describe the process by which estrangement is experienced among the Filipino gay older adults. Strauss and Corbin’s Grounded Theory (1990) design was utilized. A total of 10 gay older persons were purposively chosen to participate in semi-structured interviews. Field texts were subjected to thematic analysis involving open, axial, and selective coding. The study generated The Sailing Model of Estrangement. Remarkably, three phases relative to estrangement emerged, namely: sequestering, striving, and surviving. Primarily, the sequestering phase involves the gay persons’ need to express self, search for acceptance, and its subsequent reactions. The striving phase typifies the struggle in dealing with estrangement leading to either feelings of depression, remorse and shame or positivity, hopefulness, and motivation. Finally, in the surviving phase, gay persons may either feel contented and fulfilled or sad, lonely, and remorseful as they acquiesce aging with estrangement. Findings of the study offer an understanding of how Filipino gay older adults employ coping strategies in response to estrangement.  相似文献   
79.
In this commentary, I first consider what Oliveira defines inquiry-based science instruction to be. Next I discuss what the discourse practices are that he is advocating. Then I examine what he presents as evidence of changes in two teachers’ discourse practices due to a summer institute and how their pragmatic awareness seems to have been enhanced through institute activities. Finally I ponder whether, when, how, and why professional development should include a focus on ways of speaking during inquiry-based science instruction.  相似文献   
80.
Queries submitted to search engines can be classified according to the user goals into three distinct categories: navigational, informational, and transactional. Such classification may be useful, for instance, as additional information for advertisement selection algorithms and for search engine ranking functions, among other possible applications. This paper presents a study about the impact of using several features extracted from the document collection and query logs on the task of automatically identifying the users’ goals behind their queries. We propose the use of new features not previously reported in literature and study their impact on the quality of the query classification task. Further, we study the impact of each feature on different web collections, showing that the choice of the best set of features may change according to the target collection.  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