首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   436篇
  免费   39篇
电工技术   1篇
综合类   2篇
化学工业   146篇
金属工艺   1篇
机械仪表   14篇
建筑科学   29篇
矿业工程   1篇
能源动力   9篇
轻工业   90篇
水利工程   4篇
无线电   15篇
一般工业技术   68篇
冶金工业   56篇
原子能技术   2篇
自动化技术   37篇
  2024年   2篇
  2023年   10篇
  2022年   20篇
  2021年   29篇
  2020年   16篇
  2019年   12篇
  2018年   11篇
  2017年   20篇
  2016年   24篇
  2015年   17篇
  2014年   22篇
  2013年   37篇
  2012年   28篇
  2011年   39篇
  2010年   26篇
  2009年   20篇
  2008年   18篇
  2007年   13篇
  2006年   10篇
  2005年   11篇
  2004年   5篇
  2003年   1篇
  2002年   8篇
  2001年   6篇
  2000年   9篇
  1999年   6篇
  1998年   10篇
  1997年   3篇
  1996年   3篇
  1995年   3篇
  1994年   4篇
  1992年   5篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1977年   3篇
  1976年   2篇
  1975年   2篇
  1971年   1篇
  1970年   2篇
  1969年   1篇
  1955年   1篇
排序方式: 共有475条查询结果,搜索用时 15 毫秒
331.
332.
Reviews the books, Alcoholism treatment: An integrative family and individual approach by D. I. Davis (see record 1988-97811-000); Substance abuse and family therapy by E. Kaufman (1985); and The alcoholic family by P. Steinglass, L. A. Bennett, S. J. Wolin, and D. Reiss (see record 1987-98538-000). The book by Davis and Kaufman primarily address marital and family therapy (MFT) methods. The Steinglass et al. book presents a long-term, systematic program of theory development and research aimed at understanding the family system dynamics of alcoholic families. Davis provides excellent chapters on strategies for use in identifying and confronting alcohol problems and in getting a commitment from the family to work toward elimination of the problem drinking. The Davis book is an excellent resource; however, family and other therapists reading this book will need other resources for dealing with severe alcoholics, for moving rapidly to attain abstinence, and for dealing with long-term recovery. Kaufman's book is an excellent resource for family therapists wanting to learn more about dealing with alcoholism and other forms of substance abuse and for substance abuse therapists to learn about family therapy. The alcoholic family is an excellent book that will become a classic on this topic. We would recommend it for the serious clinician who wants a theoretical framework to guide decisions about therapeutic approaches with alcoholic families. We recommend all three books quite highly to practicing clinicians. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
333.
Correlational studies of recovery of function following traumatic brain injury have revealed weak, nonspecific relationships between outcome and injury variables. In order to better identify factors affecting recovery, 49 children (aged 6–15 yrs) were followed prospectively with repeated neuropsychological assessment of motor, visual–spatial, and somatosensory skills up to 5 yrs postinjury. Variability among growth patterns related robustly to injury variables. Younger children with severe injuries showed slower growth on visual–spatial and motor tasks than did older children of similar severity or similarly-aged children with less severe injuries. These findings support a hypothesis of increased vulnerability of rapidly emerging skills in young children and argue against an explanation of lowered recovery rates due to concomitant maturational influences on development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
334.
Leptin and its receptor are essential for regulating food intake, energy expenditure, glucose homeostasis and fertility. Mutations within leptin or the leptin receptor cause early-onset obesity and hyperphagia, as described in human and animal models. The effect of both heterozygous and homozygous variants is much more investigated than compound heterozygous ones. Recently, we discovered a spontaneous compound heterozygous mutation within the leptin receptor, resulting in a considerably more obese phenotype than described for the homozygous leptin receptor deficient mice. Accordingly, we focus on compound heterozygous mutations of the leptin receptor and their effects on health, as well as possible therapy options in human and animal models in this review.  相似文献   
335.
High-speed, single-shot velocity-map imaging (VMI) is combined with carrier-envelope phase (CEP) tagging by a single-shot stereographic above-threshold ionization (ATI) phase-meter. The experimental setup provides a versatile tool for angle-resolved studies of the attosecond control of electrons in atoms, molecules, and nanostructures. Single-shot VMI at kHz repetition rate is realized with a highly sensitive megapixel complementary metal-oxide semiconductor camera omitting the need for additional image intensifiers. The developed camera software allows for efficient background suppression and the storage of up to 1024 events for each image in real time. The approach is demonstrated by measuring the CEP-dependence of the electron emission from ATI of Xe in strong (≈10(13)?W/cm(2)) near single-cycle (4 fs) laser fields. Efficient background signal suppression with the system is illustrated for the electron emission from SiO(2) nanospheres.  相似文献   
336.
Hybrid metal oxide nano‐ and microstructures exhibit novel properties, which make them promising candidates for a wide range of applications, including gas sensing. In this work, the characteristics of the hybrid ZnO‐Bi2O3 and ZnO‐Zn2SnO4 tetrapod (T) networks are investigated in detail. The gas sensing studies reveal improved performance of the hybrid networks compared to pure ZnO‐T networks. For the ZnO‐T‐Bi2O3 networks, an enhancement in H2 gas response is obtained, although the observed p‐type sensing behavior is attributed to the formed junctions between the arms of ZnO‐T covered with Bi2O3 and the modulation of the regions where holes accumulate under exposure to H2 gas. In ZnO‐T‐Zn2SnO4 networks, a change in selectivity to CO gas with high response is noted. The devices based on individual ZnO‐T‐Bi2O3 and ZnO‐T‐Zn2SnO4 structures showed an enhanced H2 gas response, which is explained on the basis of interactions (electronic sensitization) between the ZnO‐T arm and Bi2O3 shell layer and single Schottky contact structure, respectively. Density functional theory‐based calculations provide mechanistic insights into the interaction of H2 and CO gas molecules with Bi‐ and Sn‐doped ZnO(0001) surfaces, revealing changes in the Fermi energies, as well as charge transfer between the molecules and surface species, which facilitate gas sensing.  相似文献   
337.
This paper presents two approaches for the design of an interval Type-2 TSK Fuzzy Logic System (FLS), taking into account the uncertainties about the consequent parameters. While the first approach deals with the tuning of the consequent parameters used for the system output computation, the second one, based on a linear Chebyshev fitting, shows more robustness as it considers the consequent sets instead of only the consequent crisp values. This approach deals with all parameters at the consequent level, by taking into account the upper and lower bounds of the consequent set instead of the mean value. The effectiveness of both approaches in terms of robustness to noise is evaluated through the design of IT2 TSK FLS A1-C1 forecasters for the Mackey-Glass time-series.  相似文献   
338.
Effects of different pretreatments of seabass skin and various drying methods on properties and fishy odor/flavor of resulting gelatin were evaluated. All gelatins contained α- and β-chains as the predominant components. Generally, a higher gel strength was found in the freeze-dried gelatin, compared with spray-dried counterpart (p < 0.05). Gel strength of gelatin decreased as the inlet temperature for spray drying increased (p < 0.05). All gelatin samples had creamy whitish color but became more yellow as the inlet temperature for spray drying increased. All gelatin gels were sponge- or coral-like in structure. Gelatin from skin pretreated with citric acid had lower fishy odor/flavor than that from skin pretreated using acetic acid. The lower fishy odor/flavor with coincidentally lower abundance of volatile compounds, including aldehydes, ketones, and alcohols, etc., was found in gelatin obtained by spray drying, in comparison with its freeze-dried counterpart. The lower fishy odor/flavor in spray-dried gelatin was in accordance with the lower thiobarbituric acid reactive substances and peroxide values. Thus, spray drying in conjunction with an appropriated pretreatment could be an effective method for production of gelatin with negligible undesirable fishy odor and flavor.  相似文献   
339.

This paper proposes a multilingual audio information management system based on semantic knowledge in complex environments. The complex environment is defined by the limited resources (financial, material, human, and audio resources); the poor quality of the audio signal taken from an internet radio channel; the multilingual context (Spanish, French, and Basque that is in under-resourced situation in some areas); and the regular appearance of cross-lingual elements between the three languages. In addition to this, the system is also constrained by the requirements of the local multilingual industrial sector. We present the first evolutionary system based on a scalable architecture that is able to fulfill these specifications with automatic adaptation based on automatic semantic speech recognition, folksonomies, automatic configuration selection, machine learning, neural computing methodologies, and collaborative networks. As a result, it can be said that the initial goals have been accomplished and the usability of the final application has been tested successfully, even with non-experienced users.

  相似文献   
340.
Tropical reservoirs are important for numerous socioeconomic and ecological reasons, including water supply, fishing and flood control. These functions are easily compromised, however, when reservoirs undergo accelerated sedimentation with increased inputs of chemical contaminants. The present study applied the concept of sediment core analysis to evaluate the sedimentation rate in Owabi Reservoir, which has served as a source of drinking water supply in Kumasi, Ghana, for nearly a century. The temporal variation of contamination from heavy metals was also assessed over this period. The sedimentation rate for Owabi Reservoir was estimated to be 6.82 mm/year, suggesting a relatively low rate of sedimentation, which is ecologically healthy in preventing a rapid loss of reservoir water volume. Heavy metal concentrations in the sediment cores taken from the reservoir reflected varying degree of contamination from the 1930s to 2010s. The concentration of iron (Fe) (1,560–1,770 mg/kg) was found to be the highest among the metals in the sediment core, while mercury (Hg) concentration (0.01–0.04 mg/kg) was the lowest. Lead (Pb) contamination peaked in the 1980s. Arsenic (As) and mercury (Hg) contamination exhibited more recent peaks in the 2000s, coinciding with recent widespread issues of artisanal and small‐scale gold mining (ASGM) in Ghana. Thus, even though ASGM activities are known to occur in remote districts, releases from such activities might eventually contaminate reservoirs designated as urban drinking water supplies.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号