全文获取类型
收费全文 | 4861篇 |
免费 | 494篇 |
国内免费 | 322篇 |
专业分类
电工技术 | 350篇 |
技术理论 | 1篇 |
综合类 | 605篇 |
化学工业 | 498篇 |
金属工艺 | 161篇 |
机械仪表 | 156篇 |
建筑科学 | 934篇 |
矿业工程 | 160篇 |
能源动力 | 68篇 |
轻工业 | 448篇 |
水利工程 | 171篇 |
石油天然气 | 169篇 |
武器工业 | 44篇 |
无线电 | 196篇 |
一般工业技术 | 286篇 |
冶金工业 | 496篇 |
原子能技术 | 36篇 |
自动化技术 | 898篇 |
出版年
2024年 | 32篇 |
2023年 | 101篇 |
2022年 | 180篇 |
2021年 | 208篇 |
2020年 | 164篇 |
2019年 | 140篇 |
2018年 | 121篇 |
2017年 | 142篇 |
2016年 | 157篇 |
2015年 | 158篇 |
2014年 | 270篇 |
2013年 | 241篇 |
2012年 | 271篇 |
2011年 | 320篇 |
2010年 | 259篇 |
2009年 | 271篇 |
2008年 | 302篇 |
2007年 | 299篇 |
2006年 | 298篇 |
2005年 | 308篇 |
2004年 | 227篇 |
2003年 | 198篇 |
2002年 | 198篇 |
2001年 | 146篇 |
2000年 | 118篇 |
1999年 | 104篇 |
1998年 | 67篇 |
1997年 | 61篇 |
1996年 | 54篇 |
1995年 | 31篇 |
1994年 | 47篇 |
1993年 | 39篇 |
1992年 | 25篇 |
1991年 | 22篇 |
1990年 | 21篇 |
1989年 | 23篇 |
1988年 | 12篇 |
1987年 | 3篇 |
1986年 | 7篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1974年 | 2篇 |
1966年 | 2篇 |
1964年 | 2篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有5677条查询结果,搜索用时 14 毫秒
991.
欧阳斌燊 《Canadian Metallurgical Quarterly》2011,20(8)
生发中心是B细胞成熟和发育的场所,生发中心B细胞的活化和分化受复杂的内在信号和转录因子网络调控.正常情况下,这些转录因子之间的相互作用维持着生发中心内B细胞的动态稳定.当机体细胞遗传学发生改变、病毒感染等,多种转录因子的异常表达引起B细胞内在信号网络调节失去平衡,表现为B细胞增殖异常,凋亡、分化受阻.B细胞恶性肿瘤常与B细胞的遗传学改变及生发中心转录因子异常表达有关. 相似文献
992.
Kleinspehn-Ammerlahn Anna; Riediger Michaela; Schmiedek Florian; von Oertzen Timo; Li Shu-Chen; Lindenberger Ulman 《Canadian Metallurgical Quarterly》2011,47(3):632
Many social interactions require the synchronization—be it automatically or intentionally—of one's own behavior with that of others. Using a dyadic drumming paradigm, the authors delineate lifespan differences in interpersonal action synchronization (IAS). Younger children, older children, younger adults, and older adults in same- and mixed-age dyads were instructed to drum in synchrony with their interaction partner at a constant, self-chosen tempo. Adult-only dyads showed the highest and children-only the lowest levels of IAS accuracy. It is important to note that children improved reliably in IAS accuracy when paired with older partners. The observed age-related differences in IAS accuracy remained reliable after statistically controlling for individual differences in the ability to synchronize to a metronome and for between-dyad differences in tempo. The authors conclude that IAS improves from middle childhood to adulthood and that adult interaction partners may facilitate its development. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
993.
Livingstone Andrew G.; Spears Russell; Manstead Antony S. R.; Bruder Martin; Shepherd Lee 《Canadian Metallurgical Quarterly》2011,11(4):754
Building on intergroup emotion research, we test the idea that intergroup emotion influences self-categorization. We report two studies using minimal (Study 1) and natural (Study 2) groups in which we measured participants' emotional reactions to a group-relevant event before manipulating the emotional reactions of other ingroup members and outgroup members (anger vs. happiness in Study 1; anger vs. indifference in Study 2). Results supported the hypotheses that (a) the fit between participants' own emotional reactions and the reactions of ingroup members would influence self-categorization, and (b) the specific content of emotional reactions would shape participants' willingness to engage in collective action. This willingness was greater when emotional reactions were not only shared with other group members, but were of anger (consistent with group-based action) rather than happiness or indifference (inconsistent with group-based action). Implications for the relationship between emotion and social identities are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
994.
Tsai Jessica Chia-Chin; Knoblich Günther; Sebanz Natalie 《Canadian Metallurgical Quarterly》2011,37(5):1407
According to ideomotor theories, perceiving action effects produced by others triggers corresponding action representations in the observer. We tested whether this principle extends to actions performed by externally controlled limbs and tools. Participants performed a go–no-go version of a spatial compatibility task in which their own actions resulted in the movement of a limb or tool, whereas a second, externally controlled limb or tool was seen performing a complementary go–no-go task. Spatial compatibility effects, indicating inclusion of the externally controlled effector in action planning, were observed when the externally controlled limb was identical to the controlled limb (Experiment 1) and when actions of limbs and tools (Experiment 2) or pairs of tools (Experiment 3 and 4) were combined according to participants' motor experience. When participants acted together, controlling a tool each, spatial compatibility effects occurred regardless of motor experience (Experiment 5). These findings demonstrate that (a) externally controlled tool actions are included in action planning and (b) social context modulates how externally controlled actions are mapped onto action representations. Implications of these findings for theories of perception–action links and object processing are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
995.
Isham Eve A.; Banks William P.; Ekstrom Arne D.; Stern Jessica A. 《Canadian Metallurgical Quarterly》2011,37(5):1458
Previous work suggested the association between intentionality and the reported time of action was exclusive, with intentionality as the primary facilitator to the mental time compression between the reported time of action and its effect (Haggard, Clark, & Kalogeras, 2002). In three experiments, we examined whether mental time compression could also be observed in an unintended action. Participants performed an externally cued key press task that elicited one of two possible tones. The reported time of action shifted closer to the tone when the tone was used to indicate the winner of a race (Exp.2) compared to when the tone was meaningless and did not indicate winning (Exp.1). This suggests that reported time of an unintended action could shift toward the effect in some contexts. Furthermore, the results from Exp.2 and Exp.3 (tones were substituted with verbal feedback) showed that a presumed winning action was judged to occur earlier whereas a presumed losing action was judged to be later. These findings therefore support the view that the reported time of action is reconstructed from known temporal information rather than determined by intentionality. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
996.
Aman M. Mwafy Oh-Sung Kwon Amr Elnashai Youssef M. A. Hashash 《Canadian Metallurgical Quarterly》2011,16(3):364-374
This paper investigates the implications of ground motion spatial variability on the seismic response of an extended highway bridge. An existing 59-span, 2,164-meter bridge with several bearing types and irregularity features was selected as a reference structure. The bridge is located in the New Madrid Seismic Zone and supported on thick layers of soil deposits. Site-specific bedrock input ground motions were selected based on a refined probabilistic seismic hazard analysis of the bridge site. Wave passage and ground motion incoherency effects were accounted for after propagating the bedrock records to the ground surface. The results obtained from inelastic response-history analyses confirm the significant impact of wave passage and ground motion incoherency on the seismic behavior of the bridge. The amplification in seismic demands exceeds 150%, whereas the maximum suppression of these demands is less than 50%. The irregular and unpredictable changes in structural response owing to asynchronous earthquake records necessitate in-depth seismic assessment of major highway bridges with advanced modeling techniques to realistically capture their complex seismic response. 相似文献
997.
The neural correlates of infant and adult goal prediction: Evidence for semantic processing systems.
Reid Vincent M.; Hoehl Stefanie; Grigutsch Maren; Groendahl Anna; Parise Eugenio; Striano Tricia 《Canadian Metallurgical Quarterly》2009,45(3):620
The sequential nature of action ensures that an individual can anticipate the conclusion of an observed action via the use of semantic rules. The semantic processing of language and action has been linked to the N400 component of the event-related potential (ERP). The authors developed an ERP paradigm in which infants and adults observed simple sequences of actions. In one condition the conclusion of the sequence was anticipated, whereas in the other condition the conclusion was not anticipated. Adults and infants at 9 months and 7 months were assessed via the same neural mechanisms—the N400 component and analysis of the theta frequency. Results indicated that adults and infants at 9 months produced N400-like responses when anticipating action conclusions. The infants at 7 months displayed no N400 component. Analysis of the theta frequency provided support for the relation between the N400 and semantic processing. This study suggests that infants at 9 months anticipate goals and use similar cognitive mechanisms to adults in this task. In addition, this result suggests that language processing may derive from understanding action in early development. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
998.
根据含化合物金属熔体结构的共存理论制定了Fe- Ni- O、Ni- Co- O 和Fe- Cr- O 熔体的作用浓度计算模型,对其氧溶解度了分析,证明了氧溶解过程是一个复杂的化学反应过程,绝大部分氧参加形成金属氧化物的反应,极少部分氧以原子状态溶解于金属熔体中。 相似文献
999.
汽轮机危急遮断器的计算调整与安装浅析 总被引:1,自引:0,他引:1
对汽轮发电机组超速保护装置危急遮断器的工作原理、计算、调整与安装做了较为详尽的论述。 相似文献
1000.