全文获取类型
收费全文 | 13399篇 |
免费 | 201篇 |
国内免费 | 21篇 |
专业分类
教育 | 9345篇 |
科学研究 | 1524篇 |
各国文化 | 125篇 |
体育 | 1149篇 |
综合类 | 6篇 |
文化理论 | 98篇 |
信息传播 | 1374篇 |
出版年
2021年 | 138篇 |
2020年 | 195篇 |
2019年 | 267篇 |
2018年 | 367篇 |
2017年 | 350篇 |
2016年 | 356篇 |
2015年 | 238篇 |
2014年 | 314篇 |
2013年 | 2305篇 |
2012年 | 291篇 |
2011年 | 315篇 |
2010年 | 278篇 |
2009年 | 218篇 |
2008年 | 267篇 |
2007年 | 238篇 |
2006年 | 232篇 |
2005年 | 207篇 |
2004年 | 227篇 |
2003年 | 204篇 |
2002年 | 175篇 |
2001年 | 444篇 |
2000年 | 291篇 |
1999年 | 253篇 |
1998年 | 117篇 |
1997年 | 155篇 |
1996年 | 132篇 |
1995年 | 123篇 |
1994年 | 144篇 |
1993年 | 110篇 |
1992年 | 181篇 |
1991年 | 191篇 |
1990年 | 192篇 |
1989年 | 198篇 |
1988年 | 165篇 |
1987年 | 158篇 |
1986年 | 167篇 |
1985年 | 205篇 |
1984年 | 160篇 |
1983年 | 148篇 |
1982年 | 128篇 |
1981年 | 121篇 |
1980年 | 115篇 |
1979年 | 163篇 |
1978年 | 131篇 |
1977年 | 117篇 |
1976年 | 92篇 |
1975年 | 112篇 |
1974年 | 100篇 |
1973年 | 107篇 |
1971年 | 98篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Isis at seventy-five 总被引:1,自引:0,他引:1
962.
Harleen Mangat Tajamul Hussain C Sundaram MP JS Anandaraj 《Indian journal of clinical biochemistry : IJCB》2002,17(2):74-79
Poly A RNA status and itsin vitro translation in a rabbit reticulolysate cell free system, were assessed in the skeletal muscle of young boys with Duchenne
muscular dystrophy. Compared to normals there is a significant 48% increase in poly A RNA content of dystrophic muscle and
its translatability was increased by 56% based on35S methionine incorporation into total protein systhesised. Immunoprecipitation of the translated products with monospecific
antibodies showed that there is a 2.6 fold and a 2 fold increase in m and μ calpains respectively. This underlines the importance
of both synthetic and degenerative activities in the early pathology in DMD muscle. 相似文献
963.
In previous work it was established that the U.K. tractor industry was characterised by a high degree of technical change and that this was brought about by a process of more or less continuous incremental innovation. What was lacking was an analysis of how much technical change had been introduced and an indication of the role played by technical change in determining the performance of the U.K. tractor industry internationally. This paper concludes that on the average technical change in the industry had increased by as much as 150 percent during the years 1959–1977, though there is some indication that the rate of change might now be slowing somewhat.In order to determine the relative importance of technical change a method was developed to operationalise the distinction between price and non-price competition as well as the idea of intrinsic (technical) and associative (non-technical) factors as constituents of the latter. Based on cross-sectional data for the year 1978, it has been possible to show that British manufacturers tend to produce moderately priced tractors of low to medium technical sophistication: that German manufacturers produced the most technically sophisticated tractors; that the Italian manufacturers are not generally more sophisticated, technically, than the British producers except with respect to their development of four-wheel drive; and that COMECON-based producers combine a very low price with some degree of technical sophistication. Finally, it has been possible to show that the tractors with the highest sales are among the less sophisticated in each of the power ranges investigated and that new entrants used technical sophistication as an element of their entry strategy. The answer to the question of what allows the market leader to be market leader required the development of measures for associative non-price factors, such as the availability of a dealer network brand loyalty, resale prices of tractor models, etc. By performing a regression analysis on these measures along with previously derived measures of quality-adjusted price and relative technical sophistication it has been possible to show that market leadership is achieved as a result of a balance of a number of factors, the most important of which are the size of the dealer network, warrants cost, advertising, technical sophistication and price. 相似文献
964.
A diverse sample of doctoral students completed an on-line questionnaire assessing their supervisors' academic, personal and autonomy support and their research self-efficacy. The more task-related help and personal support students received, the more positively they evaluated their supervision. The degree to which supervisors encouraged students to think and act autonomously (autonomy support) was not uniquely associated with students' supervision satisfaction but predicted greater research self-efficacy. A combination of high levels of autonomy and academic support was associated with the highest levels of research self-efficacy, whereas when greater levels of personal support were accompanied by low levels of autonomy support, students reported lower research self-efficacy. These results indicate that effective doctoral supervision involves supporting students to voice and act on their own ideas while simultaneously providing guidance on how to complete research tasks. 相似文献
965.
In this paper, we consider the difficulties that a group of internationally educated female teachers (female IETs) encountered in the process of seeking certification in the Canadian Maritimes. We read their experiences in the context of neoliberalism, in particular how they are positioned in the labour force and also the teaching profession. We consider the material effects of differences such as gender, race, ethnicity, and regional location for the female IETs. Further, we underscore implications for teacher education. 相似文献
966.
Effective teachers are often creative ones, yet an examination of creative teaching is largely invisible in the North American creativity literature. Even within education there is little about teachers’ own creative practice. Nonetheless, there are benefits to studying creative teachers: in education it can explicate ways of enhancing teachers’ creativity and enriching praxis; and in psychology it can extend our understanding of social and interpersonal creativity, as well as everyday creativity. This paper reviews 12 Canadian case studies of creative teaching conducted by a creative teaching research group. An in-depth elaboration of two themes, creative person and community, is presented. 相似文献
967.
Not all young children benefit from book exposure in preschool age. It is claimed that the ability to hold information in
mind (short-term memory), to ignore distraction (inhibition), and to focus attention and stay focused (sustained attention) may have a moderating effect on children’s reactions to the home literacy environment. In a group of 228 junior kindergarten
children with a native Dutch background, with a mean age of 54.29 months (SD = 2.12 months), we explored therefore the relationship
between book exposure, cognitive control and early literacy skills. Parents filled in a HLE questionnaire (book sharing frequency
and an author recognition checklist as indicator of parental leisure reading habits), and children completed several tests
in individual sessions with the researcher (a book-cover recognition test, PPVT, letter knowledge test, the subtests categories
and patterns of the SON, and cognitive control measures namely digit span of the KABC, a peg tapping task and sustained attention
of the ANT). Main findings were: (1) Children’s storybook knowledge mediated the relationship between home literacy environment
and literacy skills. (2) Both vocabulary and letter knowledge were predicted by book exposure. (3) Short-term memory predicted
vocabulary over and above book exposure. (4) None of the cognitive control mechanisms moderated the beneficial effects of
book exposure. 相似文献
968.
969.
There are two indisputable findings in science education research. First, students go to school with some intuitive beliefs
about the natural world and physical phenomena that pose an obstacle to the learning of formal science. Second, these beliefs
result from the confluence of two factors, namely, their everyday experience as they interact with the world around them and
a set of operational constraints or principles that channel both perceptually and conceptually the way these experiences are
perceived and interpreted. History of science suggests that the theories of early scientists through which they sought to
explain physical phenomena relied mostly on ideas that closely fitted their experiences of the relevant phenomena. This characteristic
of the early scientific ideas is the root of the epistemological difficulties that early scientists faced in their attempts
to explain the phenomena. In this paper, we focus on the early theories in optics (from ancient Greek to the late Islamic
scientific traditions) and argue that students face some of the same epistemological problems as early scientists in explaining
vision and optical phenomena for the reason that students’ intuitive beliefs are also closely tied to particular phenomena
and as a result the underlying notions are fragmentary and lack the necessary generality that would allow them to cover many
disparate phenomena. Knowledge of these epistemological problems can help the instructor to identify the key elements for
a better understanding of the formal theory of optics and, in turn, lead to a more effective instruction. 相似文献
970.
The aim of this study was to investigate whether physical or virtual manipulative experimentation can differentiate physics learning. There were four experimental conditions, namely Physical Manipulative Experimentation (PME), Virtual Manipulative Experimentation (VME), and two sequential combinations of PME and VME, as well as a control condition (i.e., traditional instruction with absence of PME or VME). Undergraduate students' understanding of physics concepts in the domain of heat and temperature was tested in a pre- and posttest design that involved 182 participants assigned to the four experimental groups and 52 participants assigned to the control group. Conceptual tests were administered to assess students' understanding before, during and after instruction. The analyses revealed that the four experimental conditions were equally effective in promoting students' understanding of concepts in the domain of heat and temperature and better than the control condition; hence, manipulation, either physical or virtual manipulation, and not physicality, as such, at least in a context like the one of the present study, is important in physics learning. 相似文献