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   3526篇
  免费   33篇
  国内免费   6篇
教育   2195篇
科学研究   492篇
各国文化   17篇
体育   273篇
综合类   8篇
文化理论   43篇
信息传播   537篇
  2022年   21篇
  2021年   22篇
  2020年   46篇
  2019年   58篇
  2018年   112篇
  2017年   155篇
  2016年   137篇
  2015年   88篇
  2014年   105篇
  2013年   530篇
  2012年   120篇
  2011年   143篇
  2010年   116篇
  2009年   85篇
  2008年   80篇
  2007年   113篇
  2006年   62篇
  2005年   77篇
  2004年   65篇
  2003年   60篇
  2002年   53篇
  2001年   86篇
  2000年   70篇
  1999年   61篇
  1998年   54篇
  1997年   44篇
  1996年   51篇
  1995年   25篇
  1994年   33篇
  1993年   20篇
  1992年   45篇
  1991年   46篇
  1990年   29篇
  1989年   38篇
  1988年   34篇
  1987年   31篇
  1986年   35篇
  1985年   39篇
  1984年   38篇
  1983年   22篇
  1982年   33篇
  1981年   24篇
  1980年   16篇
  1979年   35篇
  1978年   30篇
  1977年   21篇
  1976年   16篇
  1974年   21篇
  1972年   25篇
  1971年   19篇
排序方式: 共有3565条查询结果,搜索用时 0 毫秒
51.
With the currently dwindling traditional applicant pool, retention is higher education's holy grail of the nineties. Western Psychological Services is marketing its new Student Adaptation to College Questionnaire (SACQ) as providing early evidence of poor adjustment and potential attrition. While the SACQ closely parallels Tinto's model of institutional departure, no previously published research addresses its ability to differentiate persisters from nonpersisters. Using discriminant analysis, the present study examined (1) the extent to which the SACQ accurately predicts student departure for a private, comprehensive university; (2) SACQ items distinguishing nonpersisters; (3) use with an incoming class; and (4) evidence linking the SACQ with intervention strategies. The paper will appeal to a wide audience, especially those concerned with enrollment management and assessment.Presented at the Thirty-first Annual Forum of the Association for Institutional Research, San Francisco, May 26–29, 1991.  相似文献   
52.
Human capital theory takes for granted that an individual's demand of education will automatically be transformed into real human capital: there is no supply constraint or, said differently, educational systems can be assimilated to 'neutral' black boxes mechanically transforming input into output. This optimistic view of human capital production was rapidly abandoned. In the late 1960s some economists began to revise the assumption that the black box's functioning was neutral with regard to human capital production. Supply-side economics of education appeared first under the form of production-function analysis. It was initially believed that the information delivered by such input/output approach would help policy makers and administrators choose the most productive 'mix' of inputs. But the major conclusion of this line of research is that there is apparently no clear and undeniable relation between both expenditure per student and the specific resources they can buy (teachers' degrees and experience, smaller student-teacher ratios) on the one hand, and student achievement on the other hand. This probably means that further conceptual development is necessary to overcome the current analytical - and also political - deadlock. This paper argues that one promising way consists of introducing organisational assets as well as non-monetary inputs into the production function paradigm.  相似文献   
53.
In order to examine factors that may deter girls' interest in science, five seventh-grade life science textbooks were analyzed for sexism in language, images, and curricular content, and for features of activities that have been found to be useful for motivating girls. Although overt sexism was not apparent, subtle forms of sexism in the selection of language, images, and curricular content were found. Activities had some features useful to girls, but other features were seldom included. Teachers may wish to use differences that were found among texts as one basis for text selection.  相似文献   
54.
55.
India seems to have the highest prevalence of osteoporosis. With growing awareness of osteoporosis and its impact on life span especially in India, special attention is being paid to early detection, management and treatment of postmenopausal osteoporosis in women. Measurement of BMD and osteocalcin are of value in estimating bone turnover rates. The aim of this study is (1) to measure the specific, sensitive bone formation marker such as osteocalcin and BMD in postmenopausal osteoporosis women and postmenopausal non-osteoporosis women; (2) the follow up study to evaluate the impact of specific antiresorptive therapy (alendronate + calcium + vitamin D) regimen in postmenopausal osteoporosis by assaying osteocalcin and BMD. Sixty clinically diagnosed postmenopausal osteoporosis patients and 60 normal subjects (postmenopausal non-osteoporosis women) were recruited as control. Mean bone mineral density T score and Z score was significantly decreased (P < 0.001) in postmenopausal osteoporosis patients as compared to controls. Highly significant increase in the mean score of BMD—T score and Z score from baseline to post therapy of 3 months was observed in postmenopausal osteoporosis women. Serum osteocalcin levels were significantly increased (P < 0.001) as compared to control group. Serum osteocalcin levels were decreased significantly (P < 0.001) from baseline to post therapy of 3 months in postmenopausal osteoporosis women. BMD is the best quantifiable predictor of osteoporotic fracture and osteocalcin is specific, sensitive, promising, currently used marker for better prognosis of osteoporosis and for monitoring responses to antiresorptive therapy.  相似文献   
56.
57.
58.
The present paper deals with the determination of unknown temperature and thermal stresses on the upper surface of a thick circular plate. A thick circular plate is subjected to arbitrary known interior temperature under steady state. The fixed circular edge and lower surface of the circular plate are thermally insulated. The governing heat conduction equation has been solved by using Hankel transform methods. The results are obtained in series form in terms of Bessel's functions. The results for displacement and stresses have been computed numerically and illustrated graphically.  相似文献   
59.
In this paper, we analyze detection of multilevel phase-shift keying (MPSK) signals transmitted over a Gamma shadowed Nakagami-m fading channel. We derive novel analytical expression, in terms of Meijer’s G function, for Fourier coefficients of the probability density function of the received signal composite phase. Under the assumption of the imperfect reference signal extraction in the receiver, which is performed from the pilot signal, the analytical expression is derived for the symbol error probability (SEP) in the form of convergent series. The existence of the error floor is identified, and expression for its computation is provided. Mathematical proofs for convergence of Fourier series are provided for both SEP and SEP floor, and novel expressions of upper bounds for truncation errors are derived in terms of elementary mathematical functions. The convergence rate of the derived expressions is examined. Numerical results are confirmed independently by Monte-Carlo simulations.  相似文献   
60.
There has been considerable media coverage highlighting the lack of gender diversity in Silicon Valley, stressing the relatively low participation of women in the high-tech economy. Austin offers a unique case for testing whether similar gender issues characterized other high-tech regions because the city has historically benefited from the expansion of Silicon Valley’s large high-tech firms since the 1980s. The gender-biased business practices identified in Silicon Valley firms may have been transferred to their branch plants in Austin. Our analysis shows women’s losses in middle-skill occupation employment shares were concentrated in the low-tech industry and were partially offset by job share gains in high-skill occupations in the same sector between 1980 and 2015. Men’s losses in middle-skill occupation job share were also mainly concentrated in the low-tech sector but were partially offset by employment share gains in high-skill occupations only in the high-tech industry during this period. Women made large gains in relative real median wages only in high-skill occupations in the high-tech industry while their relative real median wages in other skill occupations and in the low-tech industry stagnated around zero during this period. Men’s gains in relative median wages were also concentrated only in the high-tech industry but were less than half of women’s and were negative (between ?10 and ?21 percent) in other occupations in the high-tech industry and across all occupations in the low-tech industry. As noted in previous studies, the impact of job polarization is not well understood across sectors and gender. This study finds the high-tech industry in Austin has had unintended consequences in terms of job polarization across gender, providing relatively fewer job opportunities in high-skill occupations to women than men but offering much higher gains in relative real median wages to women than men. Males also found relatively more job opportunities in high-skill occupations in the high-tech industry than women but experienced only half of women’s gains in relative median wages in this industry between 1980 and 2015.  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