全文获取类型
收费全文 | 1756篇 |
免费 | 81篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 22篇 |
综合类 | 2篇 |
化学工业 | 312篇 |
金属工艺 | 27篇 |
机械仪表 | 27篇 |
建筑科学 | 96篇 |
矿业工程 | 1篇 |
能源动力 | 48篇 |
轻工业 | 113篇 |
水利工程 | 18篇 |
石油天然气 | 2篇 |
无线电 | 129篇 |
一般工业技术 | 439篇 |
冶金工业 | 315篇 |
原子能技术 | 12篇 |
自动化技术 | 277篇 |
出版年
2023年 | 9篇 |
2022年 | 20篇 |
2021年 | 41篇 |
2020年 | 20篇 |
2019年 | 30篇 |
2018年 | 37篇 |
2017年 | 31篇 |
2016年 | 38篇 |
2015年 | 45篇 |
2014年 | 70篇 |
2013年 | 92篇 |
2012年 | 100篇 |
2011年 | 140篇 |
2010年 | 96篇 |
2009年 | 87篇 |
2008年 | 115篇 |
2007年 | 130篇 |
2006年 | 93篇 |
2005年 | 96篇 |
2004年 | 63篇 |
2003年 | 55篇 |
2002年 | 48篇 |
2001年 | 35篇 |
2000年 | 19篇 |
1999年 | 30篇 |
1998年 | 42篇 |
1997年 | 28篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 19篇 |
1993年 | 15篇 |
1992年 | 16篇 |
1991年 | 5篇 |
1990年 | 18篇 |
1989年 | 16篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1966年 | 4篇 |
1964年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有1840条查询结果,搜索用时 187 毫秒
1.
Belcher Calvin H. Zheng Baolong MacDonald Benjamin E. Langlois Eric D. Lehman Benjamin Pearce Charles Delaney Robert Apelian Diran Lavernia Enrique J. Monson Todd C. 《Journal of Materials Science》2022,57(9):5518-5532
Journal of Materials Science - For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic... 相似文献
2.
Changmo Kim Izhar Livne‐Bar Karsten Gronert Jeremy M. Sivak 《Molecular nutrition & food research》2020,64(4)
Lipoxins (LXs) are autacoids, specialized proresolving lipid mediators (SPMs) acting locally in a paracrine or autocrine fashion. They belong to a complex superfamily of dietary small polyunsaturated fatty acid (PUFA)–metabolites, which direct potent cellular responses to resolve inflammation and restore tissue homeostasis. Together, these SPM activities have been intensely studied in systemic inflammation and acute injury or infection, but less is known about LX signaling and activities in the central nervous system. LXs are derived from arachidonic acid, an omega‐6 PUFA. In addition to well‐established roles in systemic inflammation resolution, they have increasingly become implicated in regulating neuroinflammatory and neurodegenerative processes. In particular, chronic inflammation plays a central role in Alzheimer's disease (AD) etiology, and dysregulated LX production and activities have been reported in a variety of AD rodent models and clinical tissue samples, yet with complex and sometimes conflicting results. In addition, reduced LX production following retinal injury has been reported recently by the authors, and an intriguing direct neuronal activity promoting survival and homeostasis in retinal and cortical neurons is demonstrated. Here, the authors review and clarify this growing literature and suggest new research directions to further elaborate the role of lipoxins in neurodegeneration. 相似文献
3.
4.
Silverberg Koerner Susan; Wallace Sara; Jacobs Lehman Stephanie; Lee Sun-A; Escalante Kristine A. 《Canadian Metallurgical Quarterly》2004,18(1):46
This study addressed two main questions: (a) Are adolescent sons and daughters exposed to sensitive maternal disclosures after divorce with similar frequency and in similar detail? and (b) Does gender act as a moderator in the association between maternal disclosures and adolescent adjustment difficulties? Forced-choice and open-ended data were collected from 194 adolescents within 2 years after their parents' divorce. Quantitative analyses revealed that although the majority of adolescents experience some level of maternal disclosure, neither frequency nor detail of maternal disclosure differed as a function of adolescent gender. Frequent and detailed maternal disclosures were associated with adolescent adjustment difficulties, primarily psychological distress. Gender did not moderate that significant association. Qualitative analysis shed light on the link between maternal disclosures and adolescent distress, suggested the importance of how disclosures are made, and revealed several gender differences in reactions to maternal disclosures. Implications of the findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Barch Deanna M.; Mitropoulou Vivian; Harvey Philip D.; New Antonia S.; Silverman Jeremy M.; Siever Larry J. 《Canadian Metallurgical Quarterly》2004,113(4):556
Research suggests that schizotypal personality disorder (SPD) is a part of the spectrum of schizophrenia-related illnesses. This article hypothesizes that a deficit in the representation and maintenance of context is a core cognitive disturbance in schizophrenia and that SPD individuals should demonstrate context-processing deficits. To test this hypothesis, the authors administered 3 versions of their AX-CPT task, designed to assess context processing, to 35 healthy controls and 26 individuals with DSM-IV SPD. They also administered working memory and selective attention tasks. SPD individuals displayed context representation deficits similar to those found in schizophrenia but did not show the same additional deficits in context maintenance. Context processing was strongly associated with working memory and selective attention performance in the SPD individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
The global market for liquid mixed‐metal stabilizers is migrating toward heavy‐metal‐free products, Historically, these systems have not been performance and cost competitive. High efficiency calcium‐zinc stabilizers have the potential to replace heavy‐metal‐based products. The intrinsic value of non‐phenolic lubricating calcium intermediates and calcium‐zinc stabilizers is discussed. 相似文献
7.
8.
Replies to the comments by R. A. R. Gurung (see record 2003-03405-011) and J. Li (see record 2003-03405-012) regarding comments on the article by R. G. Tweed and D. R. Lehman (2001) which stated that a Confucian-Socratic framework provides a structure for analyzing culture-influenced aspects of academic learning. In this article, Tweed and Lehman argued that these ancient exemplars model approaches to learning continue to differentiate students within a modern Canadian postsecondary context. In this reply, Tweed and Lehman advise caution in how Gurung placed their Confucian-Socratic framework within the context of prior theory on education and epistemological development because these models were developed exclusively in the West. Furthermore, Tweed and Lehman believe that Li's argument misinterpreted their article, and that they should of consistently used the term "personal reform" rather than "behavioral reform" in order to communicate the depth of personal change envisioned by Confucius. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
JeremyCurtis 《今日电子》2003,(12):30-31
移动终端是一种采用先进通信协议栈的复杂系统,它需要具有与许多网络供应商设备的互操作性、支持先进而丰富的多媒体应用程序,而且,所有这些都必需在一个资源有限的嵌入式系统的约束条件下实现。提供一个满足上述要求的软件解决方案需要考虑许多方面的问题并经历诸多阶段。成功的要素是:平台质量、应用程序集成质量和产品质量。平台质量能让制造商用来生成多种设计方案的移动手机参考设计,必须提供一个用于制造高品质终端用户产品的优质平台。移动手机软件包括三个关键部分——协议栈、应用程序架构和应用程序。协议栈毫无疑问是最为复杂的… 相似文献
10.
A new integrated magnetic full wave DC/DC power converter that provides flexible transformer design by incorporating an independent output inductor winding is introduced. The transformer is implemented on a traditional three-leg magnetic core. The inductor winding can be separately designed to control the output current ripple. The cross-sectional area of the inductor core leg can be reduced dramatically. The operation and performance of the proposed circuit are verified on a 100 W prototype converter. 相似文献