全文获取类型
收费全文 | 757篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
教育 | 414篇 |
科学研究 | 268篇 |
各国文化 | 5篇 |
体育 | 16篇 |
文化理论 | 3篇 |
信息传播 | 60篇 |
出版年
2023年 | 8篇 |
2022年 | 13篇 |
2021年 | 25篇 |
2020年 | 13篇 |
2019年 | 25篇 |
2018年 | 49篇 |
2017年 | 38篇 |
2016年 | 41篇 |
2015年 | 38篇 |
2014年 | 38篇 |
2013年 | 94篇 |
2012年 | 29篇 |
2011年 | 29篇 |
2010年 | 38篇 |
2009年 | 32篇 |
2008年 | 28篇 |
2007年 | 19篇 |
2006年 | 31篇 |
2005年 | 24篇 |
2004年 | 17篇 |
2003年 | 26篇 |
2002年 | 16篇 |
2001年 | 13篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 12篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有766条查询结果,搜索用时 15 毫秒
711.
Hemanth Tumkur Lakshmikantha Naresh Kumar Ravichandran Mansik Jeon Jeehyun Kim Hyo-sang Park 《Journal of Zhejiang University. Science. B》2018,19(11):818-828
Objectives
The study was done to evaluate the efficacy of optical coherence tomography (OCT), to detect and analyze the microdamage occurring around the microimplant immediately following its placement, and to compare the findings with micro-computed tomography (μCT) images of the samples to validate the result of the present study.Methods
Microimplants were inserted into bovine bone samples. Images of the samples were obtained using OCT and μCT. Visual comparisons of the images were made to evaluate whether anatomical details and microdamage induced by microimplant insertion were accurately revealed by OCT.Results
The surface of the cortical bone with its anatomical variations is visualized on the OCT images. Microdamage occurring on the surface of the cortical bone around the microimplant can be appreciated in OCT images. The resulting OCT images were compared with the μCT images. A high correlation regarding the visualization of individual microcracks was observed. The depth penetration of OCT is limited when compared to μCT.Conclusions
OCT in the present study was able to generate high-resolution images of the microdamage occurring around the microimplant. Image quality at the surface of the cortical bone is above par when compared with μCT imaging, because of the inherent high contrast and high-resolution quality of OCT systems. Improvements in the imaging depth and development of intraoral sensors are vital for developing a real-time imaging system and integrating the system into orthodontic practice.712.
The semiconductor industry operates in a constant state of deflation. It is vital to our survival and progress in this knowledge era. The industry is extremely competitive and requires ongoing technological advances to improve performance while reducing costs to remain competitive. Gaining an understanding of important facets of this industry is essential. Besides knowing about semiconductor history, other aspects of interest include types of semiconductor products in the marketplace and their uses, typical semiconductor-chip making process, overall industry review and trends. One critical tool used by the industry to direct product and technology development is a technology roadmap. Review of the initial and current semiconductor technology roadmap would further enhance our understanding of semiconductor industry. 相似文献
713.
714.
This special issue comprises a set of six papers, in which studies are presented that use eye tracking to analyse multimedia learning processes in detail. Most of the papers focus on the effects on visual attention of animations with different design features such as spoken vs. written text, different kinds of cues, or different presentation speeds. Two contributions concern effects of learner characteristics (prior knowledge) on visual attention when learning with video and complex graphics. In addition, in some papers eye tracking is not only used as a process measure in itself, but also as input for verbal reports (i.e., cued retrospective reporting). In the two commentaries, the contributions are discussed from a multimedia learning perspective and an eye tracking perspective, by prominent researchers in those fields. Together, the contributions to this issue give an overview of the various possibilities eye tracking opens up for research on multimedia learning and instruction. 相似文献
715.
Niraj Kumar 《Journal of Higher Education Policy & Management》2016,38(6):676-689
The objectives of this paper were to explore the existing status of agricultural higher education in India, application of marketing concepts in similar institutions and to find the most appropriate marketing concept to make agricultural higher education more competitive. Extensive searches of relevant agricultural education, business management and higher educational data bases were made. It was found that agricultural higher education in India is stagnant and is facing an identity crisis among its stakeholders. Marketing theories and concepts which are now being applied in higher education across the globe have not been thought of in the context of agriculture education. A review of the literature suggested that considering the objectives, the multiplicity of stakeholders and the nature of public-funded agricultural education, marketing orientation would be most appropriate. Based on the experiences of similar institutions, the paper suggests a three-level strategy for the implementation of marketing orientation in institutions of agricultural higher education. 相似文献
716.
Rahat Kumar Narinder Singh Kartar Singh Atul Kalhan K. K. Prasad 《Indian journal of clinical biochemistry : IJCB》2004,19(1):122-128
The normal coagulation process is initiated by disruption and exposure of the subendothelial components of blood vessels.
Platelets adhere to subendothelium-bound von Willebrand factor via glycoprotein (GP) Ib complex. This initial interaction
per se and the release of platelet agonists transduce signals that leads to the rise in intracellular Ca2+ which induces shape
change, prostaglandin synthesis, release of granular contents and conformational changes in platelet Gp IIb-IIIa. Gp IIb-IIIa
in activated platelets binds fibrinogen and other adhesive proteins and mediates platelet cohesion the primary haemostatic
plug. Furthermore, the activated platelets due to aggregation, result in the formation of fibrin (secondary hemostasis). Normally
the haemostatic process plays a delicate balance between keeping the blood in the fluid state to maintain flow and rapidly
forming an occluding plug following vessel injury. Thrombosis occurs because of alteration in this delicate balance. Arterial
thrombosis occurs in the setting of previous vessel wall injury mostly because of atherosclerosis, while venous thrombosis
occurs in areas of stasis. The recent advances in understanding of the haemostatic process have led to a better understanding
of the mechanism of action of many antithrombotic drugs and identification of new targets for drug development. The molecular
target of the ticlopidine has been identified. Large numbers of IIb-IIIa inhibitors have been developed. The mechanism of
action of heparin has been defined at the molecular level. As a result, a synthetic pentasaccharide, based on antithrombin-binding
domain of heparin, has been developed and tested successfully in clinical trials. New generation direct thrombin inhibitors
are being developed. Factor Xa has a critical position at the convergence of intrinsic and extrinsic pathway. The clinical
tolerability and the efficacy of low molecular weight heparins has established that inhibition of further thrombin generation,
by blocking factor Xa alone can be an effective way of preventing thrombus growth without inactivating thrombin. A large number
of specific factor Xa inhibitors are under development. Some of these are in preliminary clinical trials and appear to be
promising. Future clinical trials will determine whether these new drugs will provide better risk-benefit ratio in treatment
of thrombotic disorders. Similarly role of thrombolytics has been clearly established in many diseases including coronary
artery disease. 相似文献
717.
Abstract This paper examines new organizational arrangements that have emerged in the context of a privatized extension system. It investigates the positioning and embedding of a network broker aimed at enhancing interaction in the privatized agricultural knowledge and information system (AKIS), to assess whether tensions reported in other sectors also manifest in agriculture and inform theory and policy on collective functions in pluralistic extension systems. It employs a case study approach using semi-structured interviews, observations, a closed questionnaire and secondary data analysis. Results show that a demand-driven way of working may prevent network brokers losing their neutrality in farmers’ eyes, but that a network broker nevertheless can be perceived as disruptive by extension service providers. Furthermore, it appears hard to make the network brokerage function self-sufficient. The paper shows that a social dilemma manifests, that is, the collective benefits are recognized, but private interests do not support the brokers’ continued existence. This prompts consideration of the need for continued public support. Public support for network broker appears to be needed, but possible (market-disturbing) interference with the activities of private extension service providers prompts critical examination of the mandates of publicly funded network brokers. 相似文献
718.
Making decisions regarding the selection of a business major is both very important and challenging for students. An understanding of this decision‐making process can be valuable for students, parents, and university programs. The current study applies the Theory of Reasoned Action (TRA) consumer decision‐making model to examine factors that influence college students’ intentions to choose a business major. A total of 670 undergraduate students enrolled at a large midwestern university participated in the study. Social image, job availability, and aptitude were found to be significant factors that impact students’ decisions to select a business major. The results also reveal that family, high‐school counselors, and professors have a major influence on students’ decisions. Furthermore, some unique differences were found related to gender and decided/undecided status of students. The implications of these results for promoting different majors and future research are discussed. 相似文献
719.
This article concerns new developments in autologous adult stem cell research in Japan and India through the notions of biohierarchy and bionetworking. It conceptualizes how human subject research in one country may be turned into experimental stem cell therapies in another through bionetworks. We analyse the processes that enable researchers in Japan to discard a therapy as being of reputational risk, while researchers in India employ it so that it becomes reputation enhancing. At the same time, scientists from both countries collaborate in and potentially benefit from the same bionetwork. Explaining how the recruitment of patients and scientists is organized through bionetworking, this article analyses how experimental research in India thrives using Japanese technologies. The concept of biohierarchy illustrates how inequalities in health and standards of living in India and in Japan underpin the methods by which researchers, medical professionals, managers and patients collaborate in bionetworks. The concept of 'boundary object' here captures the ways in which the meaning of experimental therapy is defined by subjective categories projected onto it by patients and scientists alike. The article is based on fieldwork conducted by both authors during 3 months between September and December 2008 at various locations in India and Japan. Data for this article were collected from a wide range of interviews with stem cell researchers, medical doctors, coordinators, managers and patients, primary and secondary sources gathered at these centres, and through web and archival research. 相似文献
720.
Masking the bitter taste of drugs is a potential tool for the improvement of patient compliance, which in turn decides the
commercial success of the product. To improve the palatability of a pharmaceutical product, many techniques have been developed,
which have not only improved the taste of the product, but also the stability of the drug in the formulation and performance
of the product. This article is an attempt to review strategies, technologies and tools that are used by pharmaceutical scientists
for taste-masking. 相似文献