全文获取类型
收费全文 | 3617篇 |
免费 | 200篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 29篇 |
综合类 | 2篇 |
化学工业 | 926篇 |
金属工艺 | 78篇 |
机械仪表 | 84篇 |
建筑科学 | 137篇 |
矿业工程 | 12篇 |
能源动力 | 131篇 |
轻工业 | 269篇 |
水利工程 | 30篇 |
石油天然气 | 8篇 |
无线电 | 272篇 |
一般工业技术 | 747篇 |
冶金工业 | 484篇 |
原子能技术 | 17篇 |
自动化技术 | 594篇 |
出版年
2024年 | 10篇 |
2023年 | 53篇 |
2022年 | 122篇 |
2021年 | 172篇 |
2020年 | 89篇 |
2019年 | 84篇 |
2018年 | 125篇 |
2017年 | 114篇 |
2016年 | 122篇 |
2015年 | 103篇 |
2014年 | 164篇 |
2013年 | 254篇 |
2012年 | 225篇 |
2011年 | 285篇 |
2010年 | 206篇 |
2009年 | 167篇 |
2008年 | 172篇 |
2007年 | 182篇 |
2006年 | 120篇 |
2005年 | 103篇 |
2004年 | 100篇 |
2003年 | 87篇 |
2002年 | 78篇 |
2001年 | 43篇 |
2000年 | 39篇 |
1999年 | 37篇 |
1998年 | 72篇 |
1997年 | 70篇 |
1996年 | 36篇 |
1995年 | 36篇 |
1994年 | 27篇 |
1993年 | 25篇 |
1992年 | 24篇 |
1991年 | 16篇 |
1990年 | 28篇 |
1989年 | 18篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 17篇 |
1984年 | 9篇 |
1983年 | 13篇 |
1982年 | 9篇 |
1981年 | 13篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1977年 | 9篇 |
1976年 | 21篇 |
1975年 | 8篇 |
1974年 | 9篇 |
排序方式: 共有3820条查询结果,搜索用时 15 毫秒
91.
92.
Amazon’s online service, Mechanical Turk (MTurk) has become a popular option for data collection among social scientists. Early work (Buhrmester, Kwang, & Gosling, 2011) indicated that data collection through MTurk was faster and less expensive than traditional collection methods (undergraduate human subject pool), as well as being reliable when administered at different dates. Building on their work, we sought to extend this investigation of reliability to a larger measure. For the current research we chose a 120-item measure of personality. After collecting data through MTurk, it was determined that our MTurk sample had strong test–retest reliability, indicating that they did not significantly change between administration dates. 相似文献
93.
94.
Martina Halasova Zdenek Chlup Adam Strachota Martin Cerny Ivo Dlouhy 《Journal of the European Ceramic Society》2012,32(16):4489-4495
The presented work describes mechanical properties of materials prepared by the pyrolysis of polysiloxane resins. The polymeric precursors have different chemical composition. Materials under investigation are predetermined for high temperature resistant applications usually in composite form, i.e. accompanied by some reinforcement. Instrumented hardness tests were employed for material characterisation. The Vickers hardness, Martens hardness and indentation elastic modulus were the key parameters, determined either from the standard optical technique or load–indentation depth curves. The influence of mechanical properties on the monomers ratio was established. The exposition to the temperature between 1200 °C and 1500 °C in air was applied to observe damage caused by these severe conditions. 相似文献
95.
96.
Public clients in the construction sector face a number of challenges in designing, procuring and managing major construction projects. The client’s role in bringing about project delivery has more recently been emphasized, particularly with respect to developing capabilities that facilitate the coordinating of projects through its different phases. In line with these developments, this paper sets out to examine the management of capabilities in a client organization through the lens of the dynamic capabilities framework. In particular, what is investigated is how the client organization senses, seizes and transforms opportunities. In pursuit of this objective, an exploratory case study approach is adopted which examines one of Sweden’s largest public client organizations. The study explores the concept of dynamic capabilities and its applicability to the public construction context. Although the usefulness of dynamic capabilities as an interpretive framework is recognized, it is suggested that the concept of dynamic capabilities is inadequate for addressing the specific context in which public client organizations operate. Particularly with respect to the project-based characteristic of these organizations and the difficulty in framing what constitutes “competitive advantage” for public organizations. 相似文献
97.
Accurate home location is increasingly important for urban computing. Existing methods either rely on continuous (and expensive) Global Positioning System (GPS) data or suffer from poor accuracy. In particular, the sparse and noisy nature of social media data poses serious challenges in pinpointing where people live at scale. We revisit this research topic and infer home location within 100 m×100 m squares at 70% accuracy for 76% and 71% of active users in New York City and the Bay Area, respectively. To the best of our knowledge, this is the first time home location has been detected at such a fine granularity using sparse and noisy data. Since people spend a large portion of their time at home, our model enables novel applications. As an example, we focus on modeling people’s health at scale by linking their home locations with publicly available statistics, such as education disparity. Results in multiple geographic regions demonstrate both the effectiveness and added value of our home localization method and reveal insights that eluded earlier studies. In addition, we are able to discover the real buzz in the communities where people live. 相似文献
98.
99.
We raise the question of approximating the compressibility of a string with respect to a fixed compression scheme, in sublinear time. We study this question in detail for two popular lossless compression schemes: run-length encoding (RLE) and a variant of Lempel-Ziv (LZ77), and present sublinear algorithms for approximating compressibility with respect to both schemes. We also give several lower bounds that show that our algorithms for both schemes cannot be improved significantly. Our investigation of LZ77 yields results whose interest goes beyond the initial questions we set out to study. In particular, we prove combinatorial structural lemmas that relate the compressibility of a string with respect to LZ77 to the number of distinct short substrings contained in it (its ?th subword complexity , for small ?). In addition, we show that approximating the compressibility with respect to LZ77 is related to approximating the support size of a distribution. 相似文献
100.