全文获取类型
收费全文 | 41014篇 |
免费 | 591篇 |
国内免费 | 48篇 |
专业分类
教育 | 29837篇 |
科学研究 | 3730篇 |
各国文化 | 368篇 |
体育 | 2933篇 |
综合类 | 41篇 |
文化理论 | 381篇 |
信息传播 | 4363篇 |
出版年
2021年 | 350篇 |
2020年 | 539篇 |
2019年 | 795篇 |
2018年 | 1604篇 |
2017年 | 1699篇 |
2016年 | 1452篇 |
2015年 | 701篇 |
2014年 | 900篇 |
2013年 | 7524篇 |
2012年 | 932篇 |
2011年 | 1262篇 |
2010年 | 993篇 |
2009年 | 843篇 |
2008年 | 1041篇 |
2007年 | 1010篇 |
2006年 | 782篇 |
2005年 | 688篇 |
2004年 | 714篇 |
2003年 | 598篇 |
2002年 | 654篇 |
2001年 | 735篇 |
2000年 | 690篇 |
1999年 | 665篇 |
1998年 | 358篇 |
1997年 | 420篇 |
1996年 | 441篇 |
1995年 | 411篇 |
1994年 | 374篇 |
1993年 | 376篇 |
1992年 | 544篇 |
1991年 | 528篇 |
1990年 | 548篇 |
1989年 | 549篇 |
1988年 | 521篇 |
1987年 | 460篇 |
1986年 | 462篇 |
1985年 | 539篇 |
1984年 | 464篇 |
1983年 | 496篇 |
1982年 | 393篇 |
1981年 | 380篇 |
1980年 | 343篇 |
1979年 | 487篇 |
1978年 | 408篇 |
1977年 | 372篇 |
1976年 | 316篇 |
1975年 | 272篇 |
1974年 | 249篇 |
1973年 | 279篇 |
1971年 | 214篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
172.
Black-dyed artefacts are found in museums worldwide, many produced using an iron-tannate compound. Deterioration of iron-tannate dyed artefacts is an international preservation issue: in New Zealand the deterioration of paru (iron-tannate) dyed Māori textiles is widespread. This article reports experimental work testing the efficacy of sodium alginate, a consolidant developed for deteriorated paru-dyed muka (fibre from harakeke; Phormium tenax). The colour stability, strength retention, and acidity of paru-dyed muka consolidated with sodium alginate (0.25, 0.5, and 1% w/v in water) was tested pre- and post-artificial light ageing. This study found that sodium alginate had no negative effect on paru-dyed muka and in some cases provided benefit. Interestingly, the colour of paru-dyed muka is substantially more stable in UV-filtered light than previously recognised. Also microfading results were in agreement with visual assessments of colour change at 1 Mlux hour exposure, providing confidence in this relatively new technique to assess colour change. 相似文献
173.
Bast fibres have been commonly used as a textile material in Northern Europe since Neolithic times. However, the process of identifying the different species has been problematic, and many important questions related to their cultural history are still unanswered. For example, a modified Herzog test and the presence of calcium oxalate crystals have both been used in identification. In order to generate more reliable results, further research and advancement in multi-methodological methods is required. This paper introduces a combination of methods which can be used to identify and distinguish flax (Linum usitatissimum), hemp (Cannabis sativa), and stinging nettle (Urtica dioica). The research material consisted of reference fibres and 25 fibre samples obtained from 12 textiles assumed to be made of nettle. The textiles were from the Finno-Ugric and Historical Collections of The National Museum of Finland. The fibre samples were studied by observing the surface characteristics and cross sections with transmitted light microscopy, and by using a modified Herzog test with polarized light, in order to identify the distinguishable features in their morphological structures. The study showed that five out of 25 samples were cotton, 16 nettle, one flax, and one hemp. Findings from two samples were inconsistent. The results show that it is possible to distinguish common north European bast fibres from each other by using a combination of microscopic methods. Furthermore, by utilizing these combined methods, new and more reliable information could be obtained from historical ethnographic textiles, which creates new vistas for the interpretation of their cultural history. 相似文献
174.
Analyzing 219 blog posts from 52 self-employed women lifestyle bloggers in North America, this study shows how these digital professionals navigate tensions and communicatively constitute work flexibility. In their narratives, women bloggers employed tension management approaches such as reframing, continual connections, and reflective practice in response to tensions in enacting temporal–spatial, identity, and financial flexibility. Specifically, women followed oxymoronic constructions – disciplined freedom, branded authenticity, and dependable independence – to embrace and transform competing poles of fluidity?structure, authenticity?marketability, and independence?interconnection. Expanding work–life research to the self-employed digital labor context, this study responds to recent calls to uncover more-than tension management strategies in empirical settings and contributes to a tension-centered, contextual, and processual analysis of workplace flexibility construction. 相似文献
175.
This paper analyses the publication patterns of researchers in the field of applied sciences at Universities of Technology in South Africa. Aspects investigated include publications in SCOPUS-listed journals; number of citations and countries of publication. Collaborative research patterns at national and international levels were also investigated. A bibliometric analysis approach was followed using SCOPUS as the main source of data and analysing the articles published in selected applied science disciplines. Results show that researchers in the field of applied sciences in universities of technology have increased their number of publications over the past 10?years and are also working in conjunction with other researchers both nationally and internationally. The analysis is an important addition to the field in South Africa which helps in measuring how institutions are positively responding to government incentives in research. The results are also important to information professionals who are increasingly playing an important role in research impact assessments. 相似文献
176.
Leanne K. Knobloch Erin D. Basinger Jennifer A. Theiss 《Journal of Applied Communication Research》2018,46(1):52-73
The transition from deployment to reintegration can be stressful for returning military personnel and at-home partners, and support plays a key role in their ability to transition effectively. We draw on relational turbulence theory to advance predictions about how parameters of the relationship between returning service members and at-home partners predict their perceptions of their partner’s support during the post-deployment transition. We surveyed 235 individuals (117 returning service members, 118 at-home partners) who had experienced the transition within the past 6 months. Findings consistent with the theory indicated that relational turbulence partially mediated the negative associations that relational uncertainty and interference from a partner shared with partner support. Partner uncertainty was a direct negative predictor of partner support as well. We consider how these results extend theory, research, and practice. 相似文献
177.
Heather E. Canary Kris May Marc D. Rinehart Jahn B. Barlow 《Journal of Applied Communication Research》2018,46(2):202-222
Organizational communication scholars are increasingly called upon to use theoretical knowledge to address problematic processes in public institutions. This article reports a process improvement project focused on a university conflict of interest (COI) policy as an example of how scholars can engage theory to improve ongoing policy processes. The project team included communication scholars and research administration staff who designed, implemented, and evaluated the mixed-methods project guided by structurating activity theory. Baseline survey results were used to design the process improvement project. Results of the follow-up survey indicate that researchers who participated in some aspect of the process improvement project (i.e. attending a policy café, using the redesigned website, or reading the new Quick Reference Guide) reported higher levels of policy communication and knowledge and more positive attitudes toward the COI policy than researchers who had not engaged with process improvement efforts. We offer theoretical and practical implications of results for organizational communication scholars and practitioners. 相似文献
178.
179.
Yu. N. Schuko 《Scientific and Technical Information Processing》2018,45(3):163-167
Although the USSR and the United States had a comparable number of employees in the field of scientific information, there was a substantial difference in funding, which resulted in a lack of information support for Soviet scientists. While 90% of the publications in the United States were available almost immediately after their release, in the USSR they were delayed by 1.5 to 2 years. Since the publication of the Abstracts Journal by VINITI (AJ), its content was consistently expanding and reached its peak in 1990 (1.5 million documents per year). The next quarter of a century was characterized by a decline in both the composition of the AJ and the time required for its document coverage. The steps for restructuring VINITI activities are discussed. The focus is made on improving the limited coverage of the Russian-language part of the global flow of scientific information by Western information systems. 相似文献
180.
E.?I.?KozlovaEmail author O.?A.?Antoshkova 《Scientific and Technical Information Processing》2018,45(1):14-21
This paper characterizes the methodological foundations of national standardization in the Russian Federation, in particular in the library and information field. The activities of Technical Standardization Committee 191 Scientific and Technical Information, Librarianship, and Publishing are reported. 相似文献