全文获取类型
收费全文 | 38323篇 |
免费 | 335篇 |
国内免费 | 18篇 |
专业分类
教育 | 27920篇 |
科学研究 | 3356篇 |
各国文化 | 297篇 |
体育 | 2845篇 |
综合类 | 7篇 |
文化理论 | 608篇 |
信息传播 | 3643篇 |
出版年
2021年 | 268篇 |
2020年 | 424篇 |
2019年 | 660篇 |
2018年 | 2914篇 |
2017年 | 2845篇 |
2016年 | 2331篇 |
2015年 | 628篇 |
2014年 | 748篇 |
2013年 | 5112篇 |
2012年 | 803篇 |
2011年 | 1375篇 |
2010年 | 1322篇 |
2009年 | 927篇 |
2008年 | 1203篇 |
2007年 | 1660篇 |
2006年 | 540篇 |
2005年 | 798篇 |
2004年 | 898篇 |
2003年 | 715篇 |
2002年 | 516篇 |
2001年 | 510篇 |
2000年 | 596篇 |
1999年 | 483篇 |
1998年 | 293篇 |
1997年 | 298篇 |
1996年 | 347篇 |
1995年 | 289篇 |
1994年 | 298篇 |
1993年 | 265篇 |
1992年 | 390篇 |
1991年 | 402篇 |
1990年 | 375篇 |
1989年 | 395篇 |
1988年 | 365篇 |
1987年 | 351篇 |
1986年 | 351篇 |
1985年 | 400篇 |
1984年 | 315篇 |
1983年 | 324篇 |
1982年 | 260篇 |
1981年 | 275篇 |
1980年 | 278篇 |
1979年 | 374篇 |
1978年 | 285篇 |
1977年 | 253篇 |
1976年 | 222篇 |
1975年 | 196篇 |
1974年 | 194篇 |
1973年 | 186篇 |
1971年 | 182篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
961.
Sally Smith Colin Smith Ella Taylor-Smith Julia Fotheringham 《Journal of Further & Higher Education》2019,43(5):628-640
Students have expectations of their university education leading to graduate careers, with universities investing considerable resources in institution-wide initiatives designed to enhance opportunities for student work placements and work-related learning. However, there are large variations between courses and disciplines in student uptake of these opportunities, with limited evidence explaining why this might be the case. Recognising recent approaches which consider student identity in transitions, this study explored student attitudes to work-related learning across a range of subject disciplines. The first phase of the study used in-class surveys (N = 199) to focus on students’ self-identification and perceptions of employability initiatives. Follow-up interviews were conducted to further explore themes emerging in the survey data. The study found that, while some students drew on resources for identity work in their recognition of and approach to work-related learning, access was limited, and university resources were not always recognised or effective. The findings have implications for the design of effective graduate employability initiatives. 相似文献
962.
In this paper we study the scaling behavior of nucleotide cluster in 11 chromosomes of Encephalitozoon cuniculi Genome. The statistical distribution of nucleotide clusters for 11 chromosomes is characterized by the scaling behavior of P(S) ∝ e^-αs' where S represents nucleotide cluster size. The cluster-size distribution P(S1+S2) with the total size of sequential C-G cluster and A-T cluster S1+S2 were also studied. P(S1+S2) follows exponential decay. There does not exist the case of large C-G cluster following large A-T cluster or large A-T cluster following large C-G cluster. We also discuss the relatively random walk length function L(n) and the local compositional complexity of nucleotide sequences based on a new model. These investigations may provide some insight into nucleotide cluster of DNA sequence. 相似文献
963.
Novel high torque bearingless two-sided rotary ultrasonic motor 总被引:3,自引:0,他引:3
LI Xia CHEN Wei-shan XIE Tao LIU Jun-kao 《浙江大学学报(A卷英文版)》2007,8(5):786-792
Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which required lubricant. To solve the above problem, a bearingless travelling-wave USM is designed. First, a novel structure of the two-sided USM consisting of a two-sided teeth stator and two disk-type rotors is designed. And the excitation principle of the two-sided travelling-wave USM is analyzed. Then, using ANSYS software, we set up the model of the stator to predict the excitation frequency and modal response of the stator. The shape of the vibration mode was obtained. Last, the load characteristics of the USM are measured using ex-perimental method. The maximum stall torque and the no-load speed were obtained. The results showed that the characteristics of the two-sided USM are better than those of the conventional one-sided USM. 相似文献
964.
This study explored a theory for motivation which included aspects of both attribution theory and goal theory. Motivational
variables included beliefs about intelligence (entity or incremental), goal orientation (mastery/learning, performance-approach,
performance-avoidance) and avoidant behaviours. Grades 4 and 5 students from a large, metropolitan school district were surveyed
regarding these motivational variables across the academic domains of reading and mathematics. The relationships among these
motivational variables were explored, as well as differences across domains. A diverse sample allowed differences across ethnic
groups and socioeconomic status to be studied. Results indicate that children could have a generalised notion of motivation
that becomes differentiated when students are asked to reflect on these variables within specified domains. The existence
of few differences across ethnic and socioeconomic groups suggest that instructional style could be a more powerful influence
than either of these variables. 相似文献
965.
Anastassios Pouris 《Higher Education》2007,54(4):501-509
This article reports the results of an investigation to identify the disciplinary strengths and the international standing
of the higher education institutions in South Africa. Even though comparative assessments provide valuable information for
research administrations, researchers and students such information is not available in South Africa currently. The Essential
Science Indicators database of the Institute for Scientific Information is utilized for the investigation and six South African
universities are identified to be included in the top 1% of the world’s institutions cited in the international scientific
literature. The identified institutions are University of Cape Town, University of Pretoria, Orange Free State University,
University of Witwatersrand, University of Natal and University of Stellenbosch. Analysis of the scientific disciplines in
which the South African institutions meet the threshold requirements for inclusion in the database shows that the country
has citation footprints in only nine of the 22 broad scientific disciplines. The article identifies the international standing
of the South African universities in the various scientific disciplines, and elaborates on the consequences relevant to higher
education and science and technology policy. 相似文献
966.
Examining the effect of multiple writing tasks on Year 10 biology students’ understandings of cell and molecular biology concepts 总被引:1,自引:0,他引:1
This paper reports on a study that examined the cumulative effects on students’ learning of science, and perceptions of the
role of writing in learning, when the students engaged in multiple writing tasks with planning strategy support. The study
was conducted with Year 10 biology students who completed two consecutive units on Cells and Molecular Biology. A mixed method
study was implemented using a pre-/post-test design with a focus on student performance on higher order conceptual questions,
and semi-structured interviews with treatment students after the completion of each unit of study. Results from the quantitative
component indicated that multiple, non-conventional writing had a significant benefit in helping students learn Molecular
Biology. The results for the Cell unit were not so conclusive suggesting the strategies are most useful for novel content.
The interviews with students demonstrated that they understood and engaged successfully with both the conceptual and linguistic
demands of the tasks. These findings, taken as a whole, confirm that multiple writing tasks can support effective student
learning, provided various pedagogical conditions are met. 相似文献
967.
968.
Beliefs and attitudes resulting from the unique life experiences of teachers frame interactions with learners promoting gender
equity or inequity and the reproduction of social views about knowledge and power as related to gender. This study examines
the enactment of a female science teacher’s pedagogy (Laura), seeking to understand the implications of her beliefs and attitudes,
as framed by her interpretations and daily manifestations, as she interacts with students. Distinct influences inform the
conceptual framework of this study: (a) the social organization of society at large, governed by understood and unspoken patriarchy,
present both academically and socially; (b) the devaluing of women as “knowers” of scientific knowledge as defined by a western
and male view of science; (c) the marginalization or “feminization” of education and pedagogical knowledge. The findings reflect
tensions between attitudes and beliefs and actual teacher practice suggesting the need for awareness within existing or new
teachers about their positions as social agents and the sociological implications related to issues of gender within which
we live and work, inclusive of science teaching and learning. 相似文献
969.
Gabriele Kucsko-Stadlmayer 《Zeitschrift für Hochschulrecht, Hochschulmanagement und Hochschulpolitik: zfhr》2007,6(1):8-17
Trotz hoher Studentinnen- und Absolventinnenzahlen in den meisten Studienrichtungen ist der Anteil der Frauen an akademischen Spitzenpositionen noch immer gering. Die Gründe für dieses Missverhältnis liegen in einer Reihe spezifischer Schwierigkeiten, mit denen Frauen bei universitären Laufbahnen konfrontiert sind. Die Politik der Europäischen Union verfolgt seit 1999 das explizite Ziel, Frauen stärker in der universitären und außeruniversitären Forschung zu verankern. Mit dem Vertrag von Amsterdam wurde auch der gemeinschaftsrechtliche Rahmen neu gestaltet. Das UG 2002 hat "Frauenförderung" und "Gleichstellung von Frauen und Männern" zur Aufgabe der Universitäten und damit zu einem zentralen Teil ihres Bildungsauftrags erklärt. Die Europäische Strategie des "Gender Mainstreaming" wurde so in eine innerstaatliche, alle Universitätsorgane bindende Verpflichtung umgesetzt. Der Beitrag behandelt die rechtlichen Möglichkeiten der vollrechtsfähigen Universitäten zur Frauenförderung und bewertet Reichweite und Wirksamkeit der neuen Rechtslage. 相似文献
970.
Chandralata Raghukumar 《Resonance》2007,12(6):24-42
The marine environment includes the nutrient-rich coastal waters, relatively nutrient-poor open oceanic waters, coral reef
atolls, metal-rich hydrothermal vent fluids with temperatures of 200–350°C, cold-seeps, estuaries, mangrove swamps, intertidal
beaches and rocky shores. Oceans are home to some of themost diverse and unique life forms. This article is an attempt to
introduce some of the fundamentals of biologicaloceanography andmarine biologyto describe life in the sea. 相似文献