全文获取类型
收费全文 | 12471篇 |
免费 | 25篇 |
国内免费 | 2篇 |
专业分类
教育 | 9660篇 |
科学研究 | 1266篇 |
各国文化 | 23篇 |
体育 | 412篇 |
文化理论 | 388篇 |
信息传播 | 749篇 |
出版年
2023年 | 7篇 |
2022年 | 5篇 |
2021年 | 16篇 |
2020年 | 25篇 |
2019年 | 35篇 |
2018年 | 2206篇 |
2017年 | 2114篇 |
2016年 | 1614篇 |
2015年 | 128篇 |
2014年 | 157篇 |
2013年 | 317篇 |
2012年 | 240篇 |
2011年 | 725篇 |
2010年 | 857篇 |
2009年 | 458篇 |
2008年 | 663篇 |
2007年 | 1171篇 |
2006年 | 86篇 |
2005年 | 412篇 |
2004年 | 462篇 |
2003年 | 371篇 |
2002年 | 146篇 |
2001年 | 17篇 |
2000年 | 33篇 |
1999年 | 11篇 |
1998年 | 9篇 |
1997年 | 24篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
K. Pratibha Usha Anand Rajni Agarwal 《Indian journal of clinical biochemistry : IJCB》2004,19(2):128-131
Serum adenosine deaminase (ADA), 5′ nucleotidase (5′NT) and malondialdehyde (MDA) were estimated in patients with acute infective
hepatitis (AIH) along with the routine parameters of liver disease. Present study is done to evaluate these special parameters
in patients with clinical history of AIH and to assess the utility of these parameters as diagnostic/ prognostic indices of
liver function and to correlate special parameters with routine live function tests (LFT). ADA, 5′NT and MDA along with routine
LFT was estimated in 25 patients with AIH and 25 samples from healthy voluntary blood donars served as the control group.
Routine LFT was estimated by standard clinical chemistry procedures on dade behring analyser and ADA, 5′NT and MDA were estimated
by berthlot reaction, fiske and subbarao method and thiobarbituric acid method respectively.
Statistical analysis showed that serum ADA, 5′NT and MDA were significantly higher in patients as compared with the controls.
There was a significant positive correlation between ADA and total bilirubin and MDA and total bilirubin. Hence we can conclude
that these tests would be more sensitive to diagnose the patients with AIH and that the raised bilirubin levels could be looked
upon, as a protective mechanism which the liver has evolved in order to combat oxidative stress. 相似文献
93.
Ritu Sharma Mridula Mahajan Ravi Kant 《Indian journal of clinical biochemistry : IJCB》2004,19(1):10-13
Serum total lipids (cholesterol and triglyceride), lipoproteins (VLDL, LDL and HDL) and Apolipoprotein-B levels of normal
healthy individuals (n=25) and coronary artery disease patients (n=25) were estimated. The objective of the present study
was to ascertain the role of apo-B in causation and inheritance of coronary artery disease. It was observed that on an average
serum total cholesterol and triglyceride more than 200 mg/dl bring the individuals to a risk of coronary artery disease (CAD)
irrespective of the age. CAD patients achieved this value at an early age (35–45 years). Similarly VLDL and LDL levels were
found to be significantly raised in CAD patients when compared to that of age matched normal individuals, with patients achieving
risk values at an early age. HDL levels were found to be significantly lower in CAD patients as compared to normal individuals.
Serum apo-B levels were significantly raised in CAD patients as compared to age matched normal individuals. Patients with
positive family history of CAD had raised serum apo-B levels than those having negative family history. A positive coefficient
of correlation was observed between serum apo-B and LDL levels suggesting that more the number of Apo-B particles, more will
be the synthesis of atherogenic particle (LDL). Patients with negative family history had serum apo-B levels closer to those
of normal individuals and in these individuals HDL levels were found to be significantly lowered, suggesting that loss of
scavenger role of HDL could be the risk factor responsible for the causation of CAD in these patients, with negative family
history of coronary artery disease. 相似文献
94.
Miriam Delgado-Verde Javier Amores-Salvadó Gregorio Martín-de Castro José Emilio Navas-López 《知识管理研究与实践》2014,12(3):261-275
Although the importance of intellectual capital has already been highlighted in the management literature, few articles have focused on the importance of its green counterpart, green intellectual capital. Nowadays, when environmental concerns cannot be ignored by firms, it is therefore time to explore the role of green intellectual capital in environmental improvement. For that reason, our research aims to explore the relationships between green intellectual capital components and the environmental performance of the firms. In particular, we try to show the importance of green organizational and social capital in the development of environmental product innovations, which are vital to the development and implementation of environmental strategies since, as scholars have pointed out, they generate some of the greatest environmental impacts. The empirical results show that green organizational capital has an indirect impact on environmental product innovation through green social capital, meaning that the latter is a significant mediator of that relationship, and at the same time emphasizing that informal relationships play a key role in the improvement of the environmental performance of the firm and, more specifically, in the development of environmental product innovations. 相似文献
95.
This study aims to examine the relationships between managerial learning as a facet of knowledge absorption (KA), firm innovation as a facet of knowledge exploitation (KE), and performance of small firms (i.e., firms with fewer than 50 employees). It builds on the knowledge-based view of the firm and the upper echelons theory to describe the effects of KA on KE, and that of KE on firm performance, in the small-firm context. Using survey data of 1441 small firms in New Zealand, the study applies a partial least squares approach to structural equation modelling to test the main hypotheses of the study. The main findings show the positive and significant effects of three types of managerial learning, namely, practice-based, proximal, and distal learning, on innovation and on innovation in firm performance. However, the curvilinear relationships suggest rather that the effects are finite and, potentially, confounded by factors unaccounted for in the models. 相似文献
96.
Kristina Andersson 《Cultural Studies of Science Education》2017,12(2):425-433
Marie Ståhl and Anita Hussénius have defined what discourses dominate national tests in chemistry for Grade 9 in Sweden by using feminist, critical didactic perspectives. This response seeks to expand the results in Ståhl and Hussénius’s article Chemistry inside an epistemological community box!—Discursive exclusions and inclusions in the Swedish national tests in chemistry, by using different facets of gender awareness. The first facet—Gender awareness in relations to the test designers’ own conceptions—highlighted how the gender order where women are subordinated men becomes visible in the national tests as a consequence of the test designers internalized conceptions. The second facet—Gender awareness in relation to chemistry—discussed the hierarchy between discourses within chemistry. The third facet—Gender awareness in relation to students—problematized chemistry in relation to the students’ identity formation. In summary, I suggest that the different discourses can open up new ways to interpret chemistry and perhaps dismantle the hegemonic chemistry discourse. 相似文献
97.
Patrick Vanden Berghe 《Journal of Web Librarianship》2016,10(4):316-326
ABSTRACTFlemish libraries have historically been praised by visitors and valued by the general public, but since the turn of the century, they have seen a decline in usage. A group of libraries in Flanders believed the role of libraries should be substantially reevaluated. They embarked on the “Delphi Project” to establish methods for libraries to become centers of their local communities by focusing on the information needs of their customers. The emergence of technology supported a shift from libraries as lending institutions to information centers. In addition to a customer service philosophy and training, online tools have helped staff reach library users. An online tool called the “Bronnenwijizer” combines searching the local library catalogue, provincial and state catalogues, and the Internet. The tool also supports the creation of “baskets” for a patron's information needs that can be shared with other staff. Delphi libraries have also used “Infopleinen,” Web-based guides to topics featuring printed media and online sources. Finally, a new online question registration system was developed that fit the new Delphi service philosophy. Over half the libraries in West-Vlaanderen are entitled to call themselves Delphi Libraries, and the philosophy is being disseminated more broadly through the Delphi Project Web site. Due to governmental changes in provincial authority, the future of the project is challenged because coordination among libraries has been critical for the project's success. 相似文献
98.
99.
Recently direct optimization of information retrieval (IR) measures has become a new trend in learning to rank. In this paper,
we propose a general framework for direct optimization of IR measures, which enjoys several theoretical advantages. The general
framework, which can be used to optimize most IR measures, addresses the task by approximating the IR measures and optimizing
the approximated surrogate functions. Theoretical analysis shows that a high approximation accuracy can be achieved by the
framework. We take average precision (AP) and normalized discounted cumulated gains (NDCG) as examples to demonstrate how
to realize the proposed framework. Experiments on benchmark datasets show that the algorithms deduced from our framework are
very effective when compared to existing methods. The empirical results also agree well with the theoretical results obtained
in the paper. 相似文献
100.
A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptually by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling. Based on this novel floating foundation, the hydrodynamic performance was investigated in the frequency domain and time domain by using the wave analysis software HydroD and DeepC from Det Norske Veritas. The frequency domain analysis was conducted to investigate the effects of the incident wave angle and water depth. The time-domain analysis was carried out to evaluate the response of the floating foundation under a selected operational condition. The hydrodynamic performances of this floating foundation with respect to time series and response spectra were also investigated in this study. 相似文献