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   897篇
  免费   18篇
教育   600篇
科学研究   59篇
各国文化   15篇
体育   88篇
文化理论   10篇
信息传播   143篇
  2023年   12篇
  2022年   14篇
  2021年   14篇
  2020年   34篇
  2019年   45篇
  2018年   53篇
  2017年   58篇
  2016年   45篇
  2015年   31篇
  2014年   44篇
  2013年   202篇
  2012年   25篇
  2011年   33篇
  2010年   17篇
  2009年   16篇
  2008年   13篇
  2007年   19篇
  2006年   12篇
  2005年   15篇
  2004年   10篇
  2003年   10篇
  2002年   9篇
  2001年   11篇
  2000年   10篇
  1999年   10篇
  1998年   6篇
  1996年   3篇
  1995年   6篇
  1994年   3篇
  1993年   7篇
  1992年   6篇
  1991年   13篇
  1990年   12篇
  1989年   4篇
  1988年   6篇
  1987年   6篇
  1986年   4篇
  1985年   3篇
  1983年   3篇
  1982年   6篇
  1981年   4篇
  1979年   4篇
  1976年   4篇
  1975年   3篇
  1974年   3篇
  1969年   4篇
  1966年   3篇
  1919年   3篇
  1860年   3篇
  1859年   4篇
排序方式: 共有915条查询结果,搜索用时 31 毫秒
31.
32.
A great deal of measurement research is currently being utilized to improve instruction at the elementary and secondary levels, but many opportunities for improving utilization are still untapped. The author proposes specific approaches to increased collaboration between researchers and practitioners to meet the burgeoning research needs of the nations' schools and to assist in data-based decision-making efforts. Society's increasing demands for accurate, usable data have contributed to the urgent current need for viable, appropriate research. This need can be met only by reseachers and practitioners working together to provide answers to critical educational questions.  相似文献   
33.
34.
35.
Building on recent breakthroughs in the field of microfluidic-based capture of rare cancer cells circulating in the blood, the present article reports on the use of Herceptin functionalized PDMS devices designed to efficiently capture from blood cancer cells, overexpressing the tyrosine kinase human epidermal growth factor receptor (HER2). The identification of patients overexpressing HER2 is critical as it typically associates with an aggressive disease course in breast cancer and poor prognosis. Importantly, HER2 positive patients have been found to significantly benefit from Herceptin (Trastuzumab), a humanized monoclonal antibody (MAb) against HER2. Disposable PDMS devices prepared using standard soft lithography were functionalized by the plasma polymerization of an epoxy-containing monomer. The epoxy-rich thin film (AGEpp) thus created could be conjugated with Herceptin either directly or through a polyethylene glycol interlayer. The properties and reactivity toward the monoclonal antibody conjugation of these coatings were determined using x-ray photoelectron spectroscopy; direct conjugation provided a good compromise in reactivity and resistance to biologically nonspecific fouling and was selected. Using the breast cancer cell line SK-BR-3 as a model for cells overexpressing HER2, the immunocapture efficacy of the Herceptin functionalized PDMS was demonstrated in model studies. Validation studies confirmed the ability of the device to efficiently capture (~80% capture yield) HER2 positive cells from full blood.  相似文献   
36.
According to the U.S. Bureau of the Census, in 1998 the 65-74 years age group (18.4 million) was eight times larger than in 1900, the 75-84 years age group (12 million) was 16 times larger, and the 85 and older years age group (4 million) was 33 times larger. It is anticipated that if this trend continues, by 2030, there will be about 70 million older American persons, more than twice their number in 1998. To meet the needs of the older population, governments, foundations, nonprofit organizations, and other groups will have to continue to work on how to increase availability, accessibility, and adequacy of community-based services. One approach will be to encourage community collaboration and partnerships. Funding agencies have encouraged university-community collaboration in recent years. However, none of the studies reviewed for this paper addressed the need for the type of university-community collaboration that our study deals with (i.e., university-community agency collaboration). In particular, our study investigates human service agency workers' perceptions of the availability, accessibility, and adequacy of services to the elderly in Northwest Ohio, and how collaboration with a university can improve service delivery to consumers. The findings of the study provide a general indication of trends, experiences, and problems common to these agencies. The findings also suggest that agency workers do not necessarily have a negative perception of university-community agency collaboration, rather many do not understand how such collaborations will improve services to consumers. Recommendations regarding how to enhance university-community collaborations are made.  相似文献   
37.
38.
The coronal and sagittal plane leg movements of 24 experienced male cyclists were assessed using video analysis while cycling on a Kingcycle windload simulator. The cyclists were grouped into those with a history of injury and an asymptomatic group on the basis of self-reported injury status. The ages, cycling experience, competition distances and competition speeds of the two groups were compared using Student's t-test. No significant differences (P < 0.05) were found for any of these variables. The maximum and minimum shank adduction, shank adduction velocities, knee flexion and ankle dorsiflexion values were also compared using Student's t-test. Significant differences were found at the point of maximum adduction (1.9 degrees; P = 0.019) and minimum dorsiflexion (4.9 degrees; P = 0.014). These differences indicated more dorsiflexion and greater abduction on the part of the symptomatic cyclists, supporting previous research that found that cyclists with a history of injury differ from those without a history of injury in the coronal plane leg movement patterns they adopt. Also, the most extreme medial position of the knee relative to the ankle occurred during knee extension. This supports the potential injury mechanism proposed by Francis (1986), which had previously only been examined using coronal plane kinematics.  相似文献   
39.
40.
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