全文获取类型
收费全文 | 34355篇 |
免费 | 78篇 |
国内免费 | 80篇 |
专业分类
系统科学 | 297篇 |
丛书文集 | 1075篇 |
教育与普及 | 84篇 |
理论与方法论 | 205篇 |
现状及发展 | 14821篇 |
研究方法 | 1390篇 |
综合类 | 16238篇 |
自然研究 | 403篇 |
出版年
2012年 | 440篇 |
2011年 | 881篇 |
2010年 | 190篇 |
2008年 | 595篇 |
2007年 | 586篇 |
2006年 | 630篇 |
2005年 | 627篇 |
2004年 | 583篇 |
2003年 | 601篇 |
2002年 | 597篇 |
2001年 | 1026篇 |
2000年 | 940篇 |
1999年 | 638篇 |
1992年 | 624篇 |
1991年 | 496篇 |
1990年 | 510篇 |
1989年 | 515篇 |
1988年 | 506篇 |
1987年 | 519篇 |
1986年 | 522篇 |
1985年 | 631篇 |
1984年 | 532篇 |
1983年 | 427篇 |
1982年 | 372篇 |
1981年 | 361篇 |
1980年 | 480篇 |
1979年 | 1027篇 |
1978年 | 895篇 |
1977年 | 905篇 |
1976年 | 619篇 |
1975年 | 670篇 |
1974年 | 1002篇 |
1973年 | 850篇 |
1972年 | 858篇 |
1971年 | 1074篇 |
1970年 | 1427篇 |
1969年 | 1070篇 |
1968年 | 1024篇 |
1967年 | 1055篇 |
1966年 | 911篇 |
1965年 | 666篇 |
1959年 | 382篇 |
1958年 | 557篇 |
1957年 | 475篇 |
1956年 | 406篇 |
1955年 | 337篇 |
1954年 | 378篇 |
1953年 | 203篇 |
1952年 | 197篇 |
1948年 | 218篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
This paper focuses on the coupling among alliances, relationships, management, and activities, when major strategic changes are carried out in an old organization. The paper also points out hownew alliances andchanged relationships seem to be developing in a Norwegian company. As a conclusion, we point out six elements which, according to our research, have to be present to minimize the implementation of reversible processes in organizations where organizational change processes have been implemented so that continued change can go on in the company. 相似文献
42.
M. J. Manohar Rao 《Systemic Practice and Action Research》1994,7(4):351-366
This paper reviews the evolutionary changes that have taken place in the systems approach to macroeconomic modeling of the Indian economy over the last 40 years in general and the last 5 years in particular. Considering the fact that the systems approach has been used both at the official level, for planning purposes, and at the academic level, as inputs to the planning process, the paper covers both these aspects in a thematic manner. Commencing from the initial official efforts, with their emphasis on aggregate consistency models, through the intermediate phases of developing programming and nonoptimizing systems and, finally, to the current academic interest in control and chaotic systems, this evolution is considered primarily against the backdrop of the changing perspectives of systems theorists and designers. 相似文献
43.
Patent documents are unique external sources of information that reveal the core technology underlying new inventions.Patents also serve as a strategic data source that can be mined to discover state-of-the-art technical development and subsequently help guide R&D investments.This research incorporates an ontology schema to extract and represent patent concepts.A clustering algorithm with non-exhaustive overlaps is proposed to overcome deficiencies with exhaustive clustering methods used in patent mining and technology discovery.The non-exhaustive clustering approach allows for the clustering of patent documents with overlapping technical findings and claims,a feature that enables the grouping of patents that define related key innovations.Legal advisors can use this approach to study potential cases of patent infringement or devise strategies to avoid litigation.The case study demonstrates the use of non-exhaustive overlaps algorithm by clustering US and Japan radio frequency identification (RFID) patents and by analyzing the legal implications of automated discovery of patent infringement. 相似文献
44.
XuB.J. 《中国科学基金(英文版)》2004,(Z1)
Nuclear technique is a powerful scientific tool in agricultural research, an area with fruitful achievements in China. Application of nuclear technique in agriculture (Nuclear Agricultural Sciences) based on the development of related science and technology is a high-tech area, and also a significant aspect of non-electrical power application of nuclear technique. As an important component of agricultural science and technology, Nuclear technique application in agricultural field has achieved a lot and made remarkable contributions to the economic, social and ecological development of China. The current paper reviews the achievements, and presents the situation of the application of nuclear technique in the Chinese a-griculture briefly. The author strongly suggests that Chinese 相似文献
45.
1 Introduction
Over the past several years, the preparation and characterization ofnanoscale magnetic materials, especially one-dimensional (1D) nanostructure, have attracted much attention as the nanomaterials would allow investigating the fundamental aspects of magnetic-ordering phenomena in magnetic materials with reduced dimensions and could lead to new potential applications such as data storage technology[1-6]. 相似文献
46.
Kang J.Y. Xu F.C. 《中国科学基金(英文版)》2004,(2):57-58,64
1 Introduction
Nanoscale science and technology have attracted greatattention since the novel properties become dominant for well-known materials as their sizes reduced to some critical dimension. These properties frequently originate in lattice distortions, structure transformations etc[1]. The variations of size and structure ofnanocrystals lead to the change of their electronic structures. Very recently, nanoscale materials with different electronic structures were utilized in fabricating nanoscale junctions[2].
…… 相似文献
47.
Karin Lffler Hugo Tschirky Kyoichi J. Kijima 《Systems Research and Behavioral Science》2009,26(6):675-687
The paper discusses how organizations can benefit from applying an enhanced Soft Systems Methodology (SSM) in innovation context. The combined approach is illustrated with an intervention in the innovation department of a multinational company. The aim of the company has been to increase its competitiveness by fostering innovation and questioning the innovation system of the company as well as the innovation project portfolio. Embedded in the SSM, the concept of Enterprise Science has been a useful vehicle to structure the problem situation and to channel the search for possible solutions. Innovation challenges could be pointed out, analysed and resolved in a systemic way. Lessons from practice are presented as well as recommendations for decision makers regarding the application of the approach and an outlook to further studies. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
48.
49.
Safety of patients in anesthesia has always been one of the major concerns of the anesthetist. It is clear from studies of safety in general that many accidents and critical incidents occur as the result of latent systemic failures to which a great number of factors contribute (Reason, 1990). An ideal way to approach this problem would be within a systemic framework, such as teleonics, developed by Járos and his co-workers (Cloete, 1999; Járos and Cloete, 1987, 1993). In this framework the events and procedures in anesthesia are considered to be part of a very complex network of process systems (teleons). It is postulated that teleonic uncertainty (telentropy) in this complex network is a factor that might lead to accidents. In a previous paper presented to the World Congress at Toronto in 2000, the principles of teleonics were described in a mathematico symbolic way (Horváth et al., 2000). This paper contains selected examples of application of these principles to the identification of possible systemic causes of accidents in anesthesia. 相似文献
50.