全文获取类型
收费全文 | 2687篇 |
免费 | 103篇 |
国内免费 | 60篇 |
专业分类
电工技术 | 10篇 |
综合类 | 178篇 |
化学工业 | 117篇 |
金属工艺 | 15篇 |
机械仪表 | 26篇 |
建筑科学 | 316篇 |
矿业工程 | 5篇 |
能源动力 | 12篇 |
轻工业 | 261篇 |
水利工程 | 9篇 |
石油天然气 | 3篇 |
武器工业 | 2篇 |
无线电 | 151篇 |
一般工业技术 | 228篇 |
冶金工业 | 1285篇 |
原子能技术 | 11篇 |
自动化技术 | 221篇 |
出版年
2024年 | 22篇 |
2023年 | 41篇 |
2022年 | 73篇 |
2021年 | 75篇 |
2020年 | 77篇 |
2019年 | 51篇 |
2018年 | 44篇 |
2017年 | 55篇 |
2016年 | 52篇 |
2015年 | 61篇 |
2014年 | 113篇 |
2013年 | 121篇 |
2012年 | 149篇 |
2011年 | 236篇 |
2010年 | 202篇 |
2009年 | 193篇 |
2008年 | 152篇 |
2007年 | 135篇 |
2006年 | 159篇 |
2005年 | 120篇 |
2004年 | 142篇 |
2003年 | 114篇 |
2002年 | 95篇 |
2001年 | 66篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 16篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 10篇 |
1986年 | 6篇 |
1984年 | 13篇 |
1981年 | 6篇 |
1979年 | 6篇 |
1966年 | 7篇 |
1965年 | 6篇 |
1964年 | 21篇 |
1963年 | 8篇 |
1961年 | 15篇 |
1960年 | 7篇 |
1959年 | 7篇 |
1958年 | 6篇 |
1957年 | 7篇 |
1956年 | 6篇 |
1955年 | 15篇 |
排序方式: 共有2850条查询结果,搜索用时 46 毫秒
1.
2.
Weigang Liang Beibei Wang Guofeng Shen Suzhen Cao Bertrand Mcswain Ning Qin Liyun Zhao Dongmei Yu Jicheng Gong Shanshan Zhao Yawei Zhang Xiaoli Duan 《Indoor air》2020,30(2):264-274
Stunting adversely affects physical and mental outcomes of children. It has not been examined whether household air pollution from solid fuel combustion is a risk factor for stunting in children. In a total of 41,439 children aged 6-17 across China, height was measured using a unified protocol. Multivariable linear regression models and logistic regression models were used to assess the associations of solid fuel use for cooking/heating with stunting in children. Adjusted for covariates, cooking/heating with solid fuel was significantly associated with a lower z-score for height for age and sex (β = −0.21 [−0.32 to −0.09] and −0.17 [−0.31 to −0.03], respectively) and an increased risk of stunting with an estimated ORs of 1.34 [1.07~1.68] and 1.37 [1.02~1.83], respectively. The risk of stunting associated with solid fuel use was statistically significant in high-age children. And the effect was greater on girls than on boys, though the difference was not statistically significant. Our study suggested that Chinese children living in households using solid fuel had a significantly higher risk of stunting than those living in households using cleaner fuel. 相似文献
3.
Stereotype threat research has demonstrated that stereotypes can harm student performance in the face of public evaluation by peers or an experimenter. The current study examined whether stereotypes can also threaten in private settings. Female students completed a math test in 3-person groups, which consisted of either 2 other women (same gender) or 2 men (minority). In addition, students either believed their performance would be broadcasted to their peers (public) or not (private). Results revealed that minority students performed worse than same-gender students in both public and private environments. This finding supports the concept of threatening intellectual environments and shows how far reaching the effects of stereotypes can be. The authors discuss these findings in relation to research on tokenism and to stereotype threat and its educational implications. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
When Teachers' and Parents' Values Differ: Teachers' Ratings of Academic Competence in Children From Low-Income Families. 总被引:1,自引:0,他引:1
The authors examined predictors of teachers' ratings of academic competence of 105 kindergarten children from low-income families. Teachers rated target children's expected competence in literacy and math and completed questions about their perceptions of congruence-dissonance between themselves and the child's parents regarding education-related values. Independent examiners assessed children's literacy and math skills. Teachers' instructional styles were observed and rated along dimensions of curriculum-centered and student-centered practices. Controlling for children's skills and socioeconomic status, teachers rated children as less competent when they perceived value differences with parents. These patterns were stronger for teachers who exhibited curriculum-centered, rather than student-centered, practices. The findings suggest a mechanism by which some children from low-income families enter a path of diminished expectations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Racial and ethnic identity development have been important topics in counseling psychology research for the last four decades. At present, however, there appears to be some confusion and debate regarding the quality of theory and measurement in the topical area. The present article serves as an introduction to this Journal of Counseling Psychology special section on "Racial and Ethnic Identity in Counseling Psychology: Conceptual and Methodological Challenges and Proposed Solutions." A rationale is provided for the special section, the place of racial and ethnic identity scholarship is located within the history of multicultural counseling research, and the invited special section contributions by K. O. Cokley (2007), J. E. Helms (2007), J. E. Trimble (2007), S. M. Quintana (2007), J. S. Phinney and A. D. Ong (2007), and J. G. Ponterotto and J. Park-Taylor (2007) are introduced. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Roberson Debi; Davidoff Jules; Davies Ian R. L.; Shapiro Laura R. 《Canadian Metallurgical Quarterly》2004,133(4):554
This study unites investigations into the linguistic relativity of color categories with research on children's category acquisition. Naming, comprehension, and memory for colors were tracked in 2 populations over a 3-year period. Children from a seminomadic equatorial African culture, whose language contains 5 color terms, were compared with a group of English children. Despite differences in visual environment, language, and education, they showed similar patterns of term acquisition. Both groups acquired color vocabulary slowly and with great individual variation. Those knowing no color terms made recognition errors based on perceptual distance, and the influence of naming on memory increased with age. An initial perceptually driven color continuum appears to be progressively organized into sets appropriate to each culture and language. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
Eisen Mitchell L.; Goodman Gail S.; Qin Jianjian; Davis Suzanne; Crayton John 《Canadian Metallurgical Quarterly》2007,43(6):1275
Memory, suggestibility, stress arousal, and trauma-related psychopathology were examined in 328 3- to 16-year-olds involved in forensic investigations of abuse and neglect. Children's memory and suggestibility were assessed for a medical examination and venipuncture. Being older and scoring higher in cognitive functioning were related to fewer inaccuracies. In addition, cortisol level and trauma symptoms in children who reported more dissociative tendencies were associated with increased memory error, whereas cortisol level and trauma symptoms were not associated with increased error for children who reported fewer dissociative tendencies. Sexual and/or physical abuse predicted greater accuracy. The study contributes important new information to scientific understanding of maltreatment, psychopathology, and eyewitness memory in children. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Kahler Christopher W.; Read Jennifer P.; Wood Mark D.; Palfai Tibor P. 《Canadian Metallurgical Quarterly》2003,17(3):226
Structural equation modeling was used to test the mediational role of social environmental selection on alcohol use in cross-sectional samples of 447 students from a rural state university and 421 students from an urban private university. Results showed that male gender, White ethnicity, and sensation seeking were uniquely associated with greater alcohol use. Mediational analyses indicated that socioenvironmental factors (i.e., Greek involvement, friends' approval of drinking/getting drunk) were positively associated with alcohol use and significantly accounted for parts of the effects of ethnicity and sensation seeking, but not gender, on alcohol use. Results suggest that White students and those high on sensation seeking may drink more heavily in college, in part because they select social environments in which alcohol use is encouraged. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Brown Charlotte; Abe-Kim Jennifer S.; Barrio Concepcion 《Canadian Metallurgical Quarterly》2003,34(1):10
What do health care practitioners need to know about providing adequate care for depressed minority women? This article examined the prevalence of depressive symptoms and clinical depression in ethnic minorities, the extent to which current health service utilization is congruent with needs, and the effectiveness of treatments provided to ethnic minorities in the primary care setting. The impact of ethnic minority women's sociocultural context on symptom expression and help-seeking behavior is also discussed. Finally, the clinical implications for accurate assessment and treatment of ethnic minority women by both medical and mental health practitioners working in the primary care sector are addressed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
The accuracy of the prediction of criminal violence may be improved by combining psychopathy with other variables that have been found to predict violence. Research has suggested that assessing intelligence (i.e., IQ) as well as psychopathy improves the accuracy of violence prediction. In the present study, the authors tested this hypothesis by using a contemporary measure of psychopathy, the Psychopathy Checklist-Revised (R. D. Hare, 2003), in a sample of 326 European American and 348 African American male offenders. The postdictive power of psychopathy was evident for both ethnic groups and robust across most changes in the operationalization of violence and the analysis conducted, whereas the postdictive power of IQ was not. No Psychopathy x IQ interactions were identified. Implications of these results for violence prediction are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献