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91.
大型水库帷幕水温分层取水效果研究 总被引:1,自引:0,他引:1
为了探索减缓已建水库对下游产生的低温水不利影响的新措施,本文以某已建大型水库为例,开展了不同帷幕布设方式对改善下泄低温水效果的研究。采用立面二维数学模型计算某大型水库坝前垂向水温结构及下泄水温过程,设计了不同遮挡高度、淹没深度及距坝轴线距离等6个帷幕方案,并对各方案的流场及温度场进行了对比分析。结果表明帷幕设置将显著影响库区的浮力流动及垂向温度分布,三种局部遮挡方案下取水口的抽吸作用导致底层低温水体绕过帷幕被较多地引用,均不能有效提高下泄水温,而底部全遮挡方案的设置对提高水库下泄水温效果明显,但同时由于持续取用表层温水,库区水温显著降低。淹没水深应结合取水层厚度确定,当淹没水深与帷幕上层取水层厚度相近时有较好的低温水改善效果。坝前1km范围内帷幕轴线位置对下泄水温的影响不明显。建议水温控制帷幕的设计采用底部全遮挡,本文中底部全遮挡帷幕方案的下泄水温5月~8月较无措施时分别升高了3.4℃、2.1℃、1.1℃、0.4℃,帷幕提高下泄水温效果明显。本文成果可为帷幕分层取水设计提供重要的借鉴。 相似文献
92.
Kaugars Astrida Seja; Klinnert Mary D.; Robinson JoAnn; Ho Martin 《Canadian Metallurgical Quarterly》2008,27(2):258
Objective: The objective of the present study was to demonstrate the reciprocal relationships between family adaptation to illness and children's medication use over time among children who presented with wheezing illness in infancy but have varying illness outcomes by age 4. Design: A longitudinal design and latent growth curve models (LGM) were used to predict change in family and caregiver adaptation to illness and children's medication use over three years among 140 infants with wheezing, among families from low socioeconomic, multi-ethnic backgrounds. Main Outcome Measures: One LGM predicted level and change (slope) of family adaptation to illness from children's baseline medication use. The second LGM predicted level and change (slope) of children's medication use from baseline family adjustment to illness. In both models, illness severity, caregivers' psychological resources, and emergency department use were covaried with the independent variable. Results: Two latent growth models were found to adequately fit the data and demonstrate full reciprocal relations between family adaptation to illness and children's medication use while accounting for baseline variables. Baseline measures of caregiver psychological functioning and illness severity were also significant predictors of family adaptation and children's medication use over time. The two models were not statistically different for children with and without active asthma at 4 years of age. Conclusion: Findings support the reciprocal effects model of child and family influences on pediatric illness and underscore the importance of early indicators of individual and family functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
93.
Arps递减曲线与甲型水驱曲线的相关性及参数计算 总被引:2,自引:0,他引:2
Arps产量递减曲线和甲型水驱曲线表达了大部分水驱油藏的基本规律。确定Arps产量递减曲线的两个参数(产量递减率和递减指数)的传统方法是通过拟合生产历史(产量)获取,但存在拟合历史应取多长、预测范围应多大这两个问题。从甲型水驱曲线出发,提出了甲型水驱油藏的产量、递减率、含油率的预测模型,确定了Arps产量递减曲线的两个参数与含水率、产油量、动态地质储量之间的关系。对不同的开发阶段,甲型水驱曲线可用几条含油率与累计产液量之间的双曲递减曲线分段描述。在产液量基本稳定的情况下,产油量与时间之间的关系也满足双曲递减规律,其递减率与年产油量、含水率成正比,与地质储量系数成反比;而递减指数取决于水油比。给出了Arps曲线与油田生产历史能够吻合的范围和预测区间的大小,以及Arps曲线与甲型水驱曲线的相关性。针对产液量基本稳定的生产过程,还给出了产油量的预测模型,用该模型预测产油量可到产油量初值的1/4~1/2,生产历史可拟合到产油量初值的1.2~1.5倍。在拟合预测区间内,甲型水驱曲线上的直线段与相应的Arps递减曲线具有相同的开发特征。图3表2参3(裴连君摘 相似文献
94.
混合调温式甲醇合成反应器的开发和应用 总被引:2,自引:0,他引:2
介绍具有结构简单,阻力小,触媒还原彻底,CO转化率高,床层温度分布合理,触媒自卸,操作稳定,调节方便等特点的混合调温式甲醇合成塔内件的开发和应用情况。 相似文献
95.
Rocio Saravia Marc Ten-Blanco Inmaculada Pereda-Prez Fernando Berrendero 《International journal of molecular sciences》2021,22(24)
Nicotine, the main psychoactive component in tobacco smoke, plays a major role in tobacco addiction, producing a high morbidity and mortality in the world. A great amount of research has been developed to elucidate the neural pathways and neurotransmitter systems involved in such a complex addictive behavior. The endocannabinoid system, which has been reported to participate in the addictive properties of most of the prototypical drugs of abuse, is also implicated in nicotine dependence. This review summarizes and updates the main behavioral and biochemical data involving the endocannabinoid system in the rewarding properties of nicotine as well as in nicotine withdrawal and relapse to nicotine-seeking behavior. Promising results from preclinical studies suggest that manipulation of the endocannabinoid system could be a potential therapeutic strategy for treating nicotine addiction. 相似文献
96.
目的 针对喷嘴导叶和双联导叶等对接结构单晶铸件内容易产生凝固缺陷的问题,研究定向凝固过程中对接平台内枝晶的生长行为、取向演化和凝固缺陷形成机制。方法 在不同抽拉速率下制备具有对接结构的镍基单晶高温合金铸件,采用实验与ProCAST有限元模拟相结合的方法,研究抽拉速率对镍基单晶高温合金对接平台内微观组织的影响,分析平台内凝固缺陷的形成机理。结果 当抽拉速率较低时,平台内枝晶生长规则,基本无凝固缺陷;随着抽拉速率的增大,平台内枝晶出现严重的侧向生长;当抽拉速率达到150 μm/s时,平台中间区域形成了碎断枝晶缺陷。结论 平台内枝晶生长与局部的温度场分布密切相关,而碎断枝晶的形成可能是由平台内部溶质富集引起的。 相似文献
97.
目的: 调查皖南地区成人的用药依从性现状,分析影响用药依从性的因素,为提高成人用药依从性提供科学依据。方法: 采用分层整群抽样的方法对 1 134 名成人进行自填式问卷调查。结果: 成人用药依从性为 43.30%,用药环境改变、药品疗效差、药品不良反应、患者经济状况差、用药存在对抗心理、医生和药师指导不明确等是导致用药非依从性的危险因素,文化程度较高是用药依从的保护因素。结论: 皖南地区成人用药依从性较低,应引起社会和卫生部门的重视,可以从个体、医院和社会三方面入手提高用药依从性。 相似文献
98.
Charnas Jocelyn W.; Hilsenroth Mark J.; Zodan Jennifer; Blais Mark A. 《Canadian Metallurgical Quarterly》2010,47(4):484
The Personality Assessment Inventory (PAI) and the Rorschach were used to investigate differences between patients who withdrew early from university-based outpatient psychodynamic psychotherapy and those who continued in treatment. The study employs two sets of analyses, one utilizing the complete sample (N = 101) and a second comprised of comparison pairs matched on the specific therapist delivering treatment (n = 36 for Rorschach; n = 38 for PAI). It was hypothesized that early withdrawers would score higher on the PAI Treatment Rejection Scale (RXR) and the PAI Treatment Process Index (TPI) than treatment continuers. It was also hypothesized that early treatment withdrawers will have better overall interpersonal relationships, less need for closeness and intimacy, less available psychological resources and more current stimulus demands, and lower levels of psychological/cognitive disturbance as measured by the Rorschach. In addition, differences between the two groups on PAI treatment and clinical scales and subscales were examined. Results indicated that PAI RXR differentiated between the two groups (p 相似文献
99.
100.