全文获取类型
收费全文 | 9325篇 |
免费 | 109篇 |
国内免费 | 6篇 |
专业分类
教育 | 6232篇 |
科学研究 | 1093篇 |
各国文化 | 322篇 |
体育 | 710篇 |
综合类 | 4篇 |
文化理论 | 62篇 |
信息传播 | 1017篇 |
出版年
2021年 | 88篇 |
2020年 | 125篇 |
2019年 | 180篇 |
2018年 | 222篇 |
2017年 | 251篇 |
2016年 | 226篇 |
2015年 | 150篇 |
2014年 | 188篇 |
2013年 | 1630篇 |
2012年 | 193篇 |
2011年 | 192篇 |
2010年 | 173篇 |
2009年 | 176篇 |
2008年 | 232篇 |
2007年 | 211篇 |
2006年 | 178篇 |
2005年 | 165篇 |
2004年 | 180篇 |
2003年 | 121篇 |
2002年 | 111篇 |
2001年 | 152篇 |
2000年 | 180篇 |
1999年 | 157篇 |
1998年 | 86篇 |
1997年 | 84篇 |
1996年 | 74篇 |
1994年 | 67篇 |
1993年 | 81篇 |
1992年 | 137篇 |
1991年 | 147篇 |
1990年 | 148篇 |
1989年 | 155篇 |
1988年 | 120篇 |
1987年 | 117篇 |
1986年 | 116篇 |
1985年 | 156篇 |
1984年 | 126篇 |
1983年 | 118篇 |
1982年 | 99篇 |
1981年 | 80篇 |
1980年 | 90篇 |
1979年 | 141篇 |
1978年 | 88篇 |
1977年 | 90篇 |
1976年 | 78篇 |
1975年 | 76篇 |
1974年 | 88篇 |
1973年 | 80篇 |
1971年 | 74篇 |
1968年 | 74篇 |
排序方式: 共有9440条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
Soma Gupta K. K. Singh V. J. Vyas V. N. Chaturvedi M. V. R. Reddy B. C. Harinath 《Indian journal of clinical biochemistry : IJCB》2000,15(1):52-55
Oxidative stress was studied by estimating plasma levels of malondialdehyde (MDA), beta carotene, vitamin E and erythrocytic
superoxide dismutase(E-SOD) activity in 50 cases of carcinoma of upper digestive tract which included carcinoma of oral cavity,
pharynx and oesophagus. While plasma MDA level was found to be increased (3.5±1.0 nmole/ml), a significant decrease in beta
carotene (81.2±14.5mg%), vitamin E (8.5±1.1 mg/L) level and E-SOD activity (657.0±80.6 U/G Hb) were observed in carcinoma
of upper digestive tract. Patients were treated with radiotherapy which itself was toxic enough and produced its deleterious
effects by generation of reactive oxygen species (ROS). As antioxdiants can detoxify ROS, beneficial effect if any, of antioxidant
administration during radiotherapy was studied in two groups of patients, group A (n=5, supplemented with antioxidants) and
group B (n=5, without antioxidant supplementation). Plasma MDA level was found to be elevated in both the groups but the increase
in group B was significant, compared to pretreatment level. Further, body weight was found to be significantly decreased in
group B patients, which was maintained in group A patients. Moreover, group A patients showed significant elevation in beta
carotene concentration, thus showing beneficial effect of administration of antioxidants during radiotherapy without disturbing
the desirable therapeutic effect of radiotherapy. 相似文献
45.
Yuen Mantak Chung Y. B. Lee Queenie A. Y. Lau Patrick S. Y. Chan Raymond M. C. Gysbers Norman C. Shea Peter M. K. 《International Journal for Educational and Vocational Guidance》2020,20(3):653-676
International Journal for Educational and Vocational Guidance - This study provides insights into how Chinese adolescents in Hong Kong interpret the concept of “meaning in life.” Data... 相似文献
46.
This study provides an expanded view of joint attention and its relation to expressive language development. A total of 144 toddlers (40 typically developing, 58 with autism spectrum disorder [ASD], 46 with developmental delay [DD]) participated at 24 and 31 months. Toddlers who screened positive for ASD risk, especially those subsequently diagnosed with ASD, had poorer joint attention skills, joint engagement during parent–toddler interaction, and expressive language. Findings highlight the dynamic relation between joint attention and language development. In the ASD and DD groups, joint engagement predicted later expressive vocabulary, significantly more than predictions based on joint attention skills. Joint engagement was most severely impacted when toddlers did not talk initially and improved markedly if they subsequently began to speak. 相似文献
47.
OBJECTIVE: To determine whether there is an age-specific incidence of hospitalized cases of Shaken Baby Syndrome (SBS) that has similar properties to the previously reported "normal crying curve," as a form of indirect evidence that crying is an important stimulus for SBS. DESIGN AND SETTING: The study analyzed cases of Shaken Baby Syndrome by age at hospitalization from hospital discharge data for California hospitals from October 1996 through December 2000. PATIENTS: All cases of children less than 18 months (78 weeks) of age for whom the diagnostic code for Shaken Baby Syndrome (995.55) in the International Classification of Disease, Ninth Edition, Clinical Modification was assigned. RESULTS: There were 273 hospitalizations for SBS. Like the "normal crying curve," the curve of age-specific incidence starts at 2-3 weeks, has a clear peak, and declines to baseline by about 36 weeks of age. In contrast to the normal crying curve that peaks at 5-6 weeks, the peak of SBS hospitalizations occurs at 10-13 weeks. CONCLUSIONS: The age-specific incidence curve of hospitalized SBS cases has a similar starting point and shape to the previously reported normal crying curve but the peak occurs about 4-6 weeks later. Of the likely predisposing causes, this pattern is only consistent with the properties of early crying. There are numerous explanations for the lag in the peaks between crying and SBS hospitalizations, including the possibility of repeat shakings prior to hospitalization. The importance of crying as a stimulus to SBS may provide an opportunity for preventive intervention. 相似文献
48.
Tae Kyoung Lee Alan Meca Jennifer B. Unger Byron L. Zamboanga Lourdes Baezconde-Garbanati Melinda Gonzales-Backen Elma I. Lorenzo-Blanco Miguel Á. Cano Sabrina E. Des Rosiers Daniel W. Soto Juan A. Villamar Monica Pattarroyo Karina M. Lizzi José Szapocznik Seth J. Schwartz 《Child development》2020,91(1):78-95
Acculturation consists of multiple domains (i.e., cultural practices, identifications, and values). However, less is known about how acculturation processes influence each other across multiple domains of acculturation. This study was designed to investigate transition patterns of acculturative processes within and across domains in a sample of 302 recent-immigrant Hispanic adolescents, Mage (SD) = 14.51 years (0.88) at baseline; male = 53%). Adolescents were assessed six times over a 3-year period. Latent profile analyses identified two profiles (high [or increasing] vs. low) for each domain at each timepoint. We found largely stable transition patterns in each domain over six timepoints. Importantly, sequential associations among profiles in acculturation domains were also detected. Implication for acculturation theory and research are discussed. 相似文献
49.
Jessica V. Whittaker Mable B. Kinzie Virginia Vitiello Jamie DeCoster Christina Mulcahy Emily A. Barton 《Journal of research on educational effectiveness》2020,13(2):177-212
abstractThis randomized controlled trial examined effects of the MyTeachingPartner-Math/Science intervention on the quality and quantity of teachers’ mathematics and science instruction, and children’s mathematics and science outcomes in 140 pre-kindergarten classrooms. Teachers participated in the intervention for two years with consecutive cohorts of children. Results from Year 1 are considered experimental, however due to high levels of attrition, results from Year 2 are considered quasi-experimental. Across both years, intervention teachers exhibited higher quality and quantity of instruction. In Year 1, there were no significant effects of the intervention on children’s outcomes. In Year 2, children in intervention classrooms made greater gains in teachers’ ratings of mathematics and science skills and performed better on a spring assessment of science skills. These results have implications for designing and evaluating professional development aimed at supporting children’s mathematics and science knowledge and skills. 相似文献
50.
PhD students’ work conditions and study environment in university- and industry-based PhD programmes
During the last 10 years, new models of funding and training PhD students have been established in Denmark in order to integrate industry into the entire PhD education. Several programmes have been conducted where it is possible to co-finance PhD scholarships or to become an employee as an industrial PhD in a company. An important question is what impact these new conditions will have on the PhD students’ training, work conditions and study environment. In this article, the new type of programmes will be presented together with data analysis of PhD students’ work conditions and study environment in various programmes mainly based on a research project from 2006. The results of this study show no significant difference between PhD students in a traditional university PhD programme and PhD students in an industrial programme concerning working environment. However, the study shows significant differences in the intercultural dimension, where foreign PhD students are significantly more satisfied with their study environment compared with Danish PhD students. In general the workload is very high and the environment is stressful for all PhD students. 相似文献