全文获取类型
收费全文 | 16920篇 |
免费 | 2082篇 |
国内免费 | 735篇 |
专业分类
电工技术 | 1810篇 |
技术理论 | 1篇 |
综合类 | 1496篇 |
化学工业 | 1571篇 |
金属工艺 | 577篇 |
机械仪表 | 810篇 |
建筑科学 | 2271篇 |
矿业工程 | 601篇 |
能源动力 | 1591篇 |
轻工业 | 1036篇 |
水利工程 | 1390篇 |
石油天然气 | 447篇 |
武器工业 | 101篇 |
无线电 | 1358篇 |
一般工业技术 | 1435篇 |
冶金工业 | 1267篇 |
原子能技术 | 148篇 |
自动化技术 | 1827篇 |
出版年
2024年 | 72篇 |
2023年 | 269篇 |
2022年 | 516篇 |
2021年 | 590篇 |
2020年 | 702篇 |
2019年 | 603篇 |
2018年 | 518篇 |
2017年 | 617篇 |
2016年 | 753篇 |
2015年 | 719篇 |
2014年 | 970篇 |
2013年 | 1102篇 |
2012年 | 1146篇 |
2011年 | 1539篇 |
2010年 | 1015篇 |
2009年 | 1043篇 |
2008年 | 1019篇 |
2007年 | 1132篇 |
2006年 | 940篇 |
2005年 | 770篇 |
2004年 | 621篇 |
2003年 | 580篇 |
2002年 | 484篇 |
2001年 | 363篇 |
2000年 | 289篇 |
1999年 | 211篇 |
1998年 | 164篇 |
1997年 | 152篇 |
1996年 | 131篇 |
1995年 | 113篇 |
1994年 | 118篇 |
1993年 | 65篇 |
1992年 | 62篇 |
1991年 | 40篇 |
1990年 | 32篇 |
1989年 | 40篇 |
1988年 | 31篇 |
1987年 | 22篇 |
1986年 | 20篇 |
1985年 | 10篇 |
1984年 | 13篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1979年 | 7篇 |
1964年 | 10篇 |
1961年 | 8篇 |
1960年 | 8篇 |
1957年 | 12篇 |
1955年 | 8篇 |
1951年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
31.
Y. MURAKAMI K. TAKAHASHI R. KUSUMOTO 《Fatigue & Fracture of Engineering Materials & Structures》2003,26(6):523-531
ABSTRACT The fatigue crack growth behaviour of 0.47% carbon steel was studied under mode II and III loadings. Mode II fatigue crack growth tests were carried out using specially designed double cantilever (DC) type specimens in order to measure the mode II threshold stress intensity factor range, ΔKIIth. The relationship ΔKIIth > ΔKIth caused crack branching from mode II to I after a crack reached the mode II threshold. Torsion fatigue tests on circumferentially cracked specimens were carried out to study the mechanisms of both mode III crack growth and of the formation of the factory‐roof crack surface morphology. A change in microstructure occurred at a crack tip during crack growth in both mode II and mode III shear cracks. It is presumed that the crack growth mechanisms in mode II and in mode III are essentially the same. Detailed fractographic investigation showed that factory‐roofs were formed by crack branching into mode I. Crack branching started from small semi‐elliptical cracks nucleated by shear at the tip of the original circumferential crack. 相似文献
32.
Reviews the book, Emotion-focused therapy: Coaching clients to work through their feelings by Leslie S. Greenberg (see record 2002-00066-000). This book was written for both novice therapists who have had little experience working with emotions in treatment, as well as for experienced therapists looking to systematize their understanding of how emotional change works. The book is divided into four parts. Part I examines the nature and function of emotions. Part II examines the first part of emotional coaching--arriving at emotion. Part III examines the second part of emotional coaching--leaving emotion. Finally, Part IV examines the application of emotion-focused therapy to the problems of living, in the context of individuals, couples therapy, and parenting. This book offers a wealth of therapeutic techniques and theoretical principles about the process of change. As such, it is an important and natural companion to seminal works in cognitive behaviour therapy and interpersonal therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
The vicissitudes of the Israeli-Palestinian peace process since 1967 are analyzed using attitudes and related concepts where relevant. The 1967 war returned the two peoples' zero-sum conflict around national identity to its origin as a conflict within the land both peoples claim. Gradually, new attitudes evolved regarding the necessity and possibility of negotiations toward a two-state solution based on mutual recognition, which became the building stones of the 1993 Oslo agreement. Lacking a commitment to a final outcome, the Oslo-based peace process was hampered by reserve options, which increased avoidance at the expense of approach tendencies as the parties moved toward a final agreement. The resulting breakdown of the process in 2000 produced clashing narratives, reflecting different anchors for judgment and classical mirror images. Public support for violence increased, even as public opinion continued to favor a negotiated two-state solution. Reviving the peace process requires mutual reassurance about the availability of a partner for negotiating a principled peace based on a historic compromise that meets the basic needs and validates the identities of both peoples. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
34.
The width of the transition layer between the crystalline and amorphous zones in nylon 1010 was determined by SAXS with point collimation and long-slit collimation, respectively. The width of the transition layer, E, was found to be 1.7 nm. The results show that the width of the transition layer is independent of crystallinity. 相似文献
35.
36.
泥浆制备中工艺改造的研究 总被引:1,自引:0,他引:1
根据室条件下粉磨试验结果,发现球磨过程中筛上料变化存在的突变范围,提出两次加料一次加水可改变泥浆颗粒分布,并找出适宜的加料种类与时间。另外给予测粒度分布提供了宝贵的试验基础数据。 相似文献
37.
通过引入归一化脉宽P和相对脉冲展宽因子q,提出了一个适用于IM/DD系统中各种眼图恶化量x和归一化脉宽P的色散限制改进公式。通过与其它理论的比较、计算机仿真和对实验数据的分析,验证了该公式的正确性,并给出了其它结果的限制条件。研究表明:当眼图恶化量x为1dB左右时,对2.5Gb/;外调制信号(α=0)而言,非色散位移光纤IM/DD系统的色散因子γ约等于0.79,所对应的系统再生中继距离约为900余公里。 相似文献
38.
With this volume, the 47-year old Canadian Journal of Psychology takes a new name and makes a renewed commitment. In retitling the journal the Canadian Journal of Experimental Psychology, the intention is to reflect more clearly what has always been the major goal of the journal--to publish the best new research in experimental psychology, both Canadian and international, in both French and English. I am honoured to become the tenth editor of the major journal for experimental psychology in Canada. CJP has served the field very well; my primary goal is to ensure that CJEP continues to do so. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
39.
Gorgievski-Duijvesteijn Marjan J.; Bakker Arnold B.; Schaufeli Wilmar B.; van der Heijden Peter G. M. 《Canadian Metallurgical Quarterly》2005,10(3):210
This study of 513 Dutch farmers tested a dynamic equilibrium model of resources (an extension of the conservation of resources theory; S. E. Hobfoll, 1989, 1998, 2001). With structural equation modeling, the advantages of a 3-wave longitudinal design were comprehensively used, such as addressing bidirectional causal effects and within-individual vs. between-individual change. This allowed for a careful analysis of the management function of resources in the stress process. Results showed that well-being had stronger within-person stability than finances. Increased levels of financial problems temporarily increased psychological distress but not self-reported illness. Conversely, farmers with higher stable baselines of psychological distress also had higher baselines of self-reported illness and experienced more negative changes in their financial situation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
40.