全文获取类型
收费全文 | 1216篇 |
免费 | 12篇 |
国内免费 | 17篇 |
专业分类
教育 | 638篇 |
科学研究 | 178篇 |
各国文化 | 4篇 |
体育 | 329篇 |
综合类 | 7篇 |
文化理论 | 2篇 |
信息传播 | 87篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 7篇 |
2020年 | 2篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 15篇 |
2013年 | 6篇 |
2012年 | 103篇 |
2011年 | 108篇 |
2010年 | 42篇 |
2009年 | 9篇 |
2008年 | 72篇 |
2007年 | 95篇 |
2006年 | 85篇 |
2005年 | 88篇 |
2004年 | 65篇 |
2003年 | 73篇 |
2002年 | 49篇 |
2001年 | 33篇 |
2000年 | 35篇 |
1999年 | 25篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 21篇 |
1995年 | 14篇 |
1994年 | 16篇 |
1993年 | 26篇 |
1992年 | 24篇 |
1991年 | 26篇 |
1990年 | 12篇 |
1989年 | 11篇 |
1988年 | 16篇 |
1987年 | 13篇 |
1986年 | 19篇 |
1985年 | 18篇 |
1984年 | 12篇 |
1983年 | 17篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1958年 | 3篇 |
1948年 | 7篇 |
1942年 | 1篇 |
1935年 | 1篇 |
1922年 | 1篇 |
1913年 | 1篇 |
排序方式: 共有1245条查询结果,搜索用时 15 毫秒
961.
R.G.Mansfield 《技术创新》2004,(9):27-30
当我们讨论产业用纺织品在可充气产品领域的用途时,大多数人比较熟悉的一种用途是用于“比空气轻的”飞艇(“lighter-than-air”craft),比如热气球、软式飞艇和齐柏林飞艇。然而,与织物有关的可充气产品包括的范围是很广的,并不仅仅限于“比空气轻”的飞行器具。. 相似文献
962.
做出预测是为了运用。在大多数公司或企业组织中,都既有搞预测的人——预测人员,也有使用预测结果的人——这些人也许可以称为经营管理人员——将预测结果运用于决策过程中。他们之间常常存在某种紧张关系。预测人员可能感到,经营管理人员对预测结果并不是那么很感兴趣,他们对预测结果不给以充分利用。经营管理人员则认为,这些预测结果不够准确,还可以大大改进。这种紧张关系,常常能够通过加强交流和适当了解对方的工作性质而得到缓和。管理人员应当注意预测中用到的各种信息,应当对用到的预测技术有所了 相似文献
963.
微生物正被证明是一种有用的萃取剂,可将金属从其矿石中提取出来。在沥滤金属的过程中它们不仅有助于加速氧化过程,而且也常常会降低总的费用。 相似文献
964.
本文探讨了图书出版业的未来并提出出版商减少风险和增加利润的战略。这些战略由于使用户更便宜、更灵活、更容易、更快地得到图书而也有利于教育、科学和技术的发展。 相似文献
965.
毕培曦 江润祥 李钳 张宏达 Chang Kiaw-Lan Wong Khoon-Meng Gray Alexander I. Waterman Peter G. 《中国科学院研究生院学报》1988,26(3):205-210
通过化学分析证明,美栌木与九里香属内的九里香组植物较为接近,两者均含月橘烯碱
及8-戊烯化香豆精,而棕茎组植物则与黄皮属植物亲缘关系较近。 据此肯定了Tanaka的观
点,认为棕茎组比九里香组原始。黄皮族内的亲缘关系亦可作如下推断: 小芸木属→山小桔属→黄皮属→九里香属棕茎组→九里香属九里香组→美栌木属。 相似文献
966.
Vitaro F Brendgen M Boivin M Cantin S Dionne G Tremblay RE Girard A Pérusse D 《Child development》2011,82(2):617-632
This study used the monozygotic (MZ) twin difference method to examine whether differences in friends' aggression increased the differences in MZ twins' aggression and depressive symptoms from kindergarten to Grade 1 and whether perceived victimization by the friend played a mediating role in this context. Participants were 223 MZ twin pairs. Results showed that differences in kindergarten friends' aggression significantly predicted an increased difference in MZ twins' aggression from kindergarten (mean age = 6.7 years) to Grade 1 (mean age = 7.5 years) for both boys and girls. Differences in perceived victimization by the friend mediated this association, albeit only in boys. Differences in perceived victimization by the friend also predicted an increase in MZ twins' differences in depressive symptoms. These results support the importance of friendship experiences during early childhood. 相似文献
967.
This study examined whether improvement in parents' depression was linked with changes in their children's depressive symptoms and functioning. Participants were 223 parents and children ranging in age from 7 to 17 years old (M = 12.13, SD =2.31); 126 parents were in treatment for depression and 97 parents were nondepressed. Children were evaluated 6 times over 2 years. Changes in parents' depressive symptoms predicted changes in children's depressive symptoms over and above the effect of time; children's symptoms significantly predicted parents' symptoms. Trajectories of children's depressive symptoms differed significantly for children of remitted versus nonremitted depressed parents, and these differences were significantly predicted by their parents' level of depression. The relation between parents' and children's depressive symptoms was partially mediated by parental acceptance. 相似文献
968.
Deaf parents and pediatric cochlear implantation: an exploration of the decision-making process 总被引:1,自引:0,他引:1
Hardonk S Daniels S Desnerck G Loots G Van Hove G Van Kerschaver E Sigurjónsdóttir HB Vanroelen C Louckx F 《American annals of the deaf》2011,156(3):290-304
The study examined factors in deaf parents' decision between cochlear implantation (CI) and traditional hearing aids for their child. The subjects were 6 Flemish children ages 5-9 years with severe/profound congenital hearing loss, with at least 1 deaf parent. The researchers, who conducted thematic content analysis of qualitative data collected through parent interviews, found that with the exception of a family with 1 hearing parent, parents gave priority to Deaf identity, sign language, and ethical issues in deciding between CI and hearing aids. Medical risks were also mentioned. The researchers conclude that the decision-making processes of the parents involved factors that have also been found among hearing parents, as well as aspects that have not been reported to play a role in hearing parents' decision making. A further conclusion is that deaf parents' perspective merits attention in professional practice and empirical research. 相似文献
969.
Infants can imitate a novel action sequence from television and picture books, yet there has been no direct comparison of infants' imitation from the 2 types of media. Varying the narrative cues available during the demonstration and test, the current experiments measured 18- and 24-month-olds' imitation from television and picture books. Infants imitated from both media types when full narrative cues (Experiment 1; N = 76) or empty, meaningless narration (Experiment 2; N = 135) accompanied the demonstrations, but they imitated more from television than books. In Experiment 3 (N = 27), infants imitated from a book based on narration alone, without the presence of pictures. These results are discussed in relation to age-related changes in cognitive flexibility and infants' emerging symbolic understanding. 相似文献
970.