全文获取类型
收费全文 | 486篇 |
免费 | 1篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 173篇 |
金属工艺 | 58篇 |
机械仪表 | 2篇 |
建筑科学 | 1篇 |
矿业工程 | 8篇 |
能源动力 | 1篇 |
轻工业 | 15篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 20篇 |
一般工业技术 | 57篇 |
冶金工业 | 113篇 |
原子能技术 | 4篇 |
自动化技术 | 27篇 |
出版年
2013年 | 16篇 |
2011年 | 6篇 |
2010年 | 4篇 |
2009年 | 7篇 |
2008年 | 8篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2003年 | 6篇 |
2002年 | 16篇 |
2001年 | 4篇 |
2000年 | 10篇 |
1999年 | 4篇 |
1998年 | 28篇 |
1997年 | 20篇 |
1996年 | 21篇 |
1995年 | 9篇 |
1994年 | 7篇 |
1993年 | 12篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 9篇 |
1977年 | 15篇 |
1976年 | 24篇 |
1975年 | 14篇 |
1974年 | 17篇 |
1973年 | 21篇 |
1972年 | 15篇 |
1971年 | 14篇 |
1970年 | 7篇 |
1969年 | 7篇 |
1968年 | 6篇 |
1967年 | 6篇 |
1966年 | 5篇 |
1965年 | 3篇 |
1964年 | 3篇 |
1963年 | 3篇 |
1926年 | 3篇 |
1921年 | 5篇 |
排序方式: 共有487条查询结果,搜索用时 15 毫秒
31.
A study was made to determine the causes which make glaze surfaces susceptible to marking by metallic objects. The effect of carbon monoxide and of varying concentrations of SO2 gas in the furnace atmosphere at 860°C, was investigated. It was found that (a) carbon monoxide does not produce surfaces which metal mark; (b) concentrations of from 0.1 to 1.2% Sop incrcase susceptibility to scratching with metals; (c) SO2 in concentrations of 3% and higher will destroy the gloss of glazes on typical hotel ware and earthenware; and (d) concentrations of SO2 of 3 to 12½% cause the glaze on one vitreous low-fired type of ware to metal mark. 相似文献
33.
This study examined the psychometric properties of the Readiness and Motivation Interview (RMI), a symptom-specific measure of readiness and motivation for change in the eating disorders. For 4 symptom domains, the RMI assesses the extent to which individuals are in precontemplation, contemplation, and action/maintenance, and the extent to which change is made for internal versus external reasons. Ninety-nine individuals with eating disorders completed the RMI and measures to assess convergent, divergent, and criterion validity. RMI profiles revealed differences in readiness and motivation across symptom domains. The RMI demonstrated good reliability and construct validity, and RMI scores predicted anticipated difficulty of recovery activities, completion of recovery activities, decision to enroll in an intensive symptom-reduction program, and treatment dropout. The RMI may have important clinical applications by providing much-needed information on client readiness for action-oriented treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
34.
Coastal marine ecosystems world-wide are threatened by invasions of nonindigenous species. The ubiquity of marine sibling species identifiable only by genetic analysis suggests that many invasions are cryptic and therefore undetected, causing an underestimation of the actual number and impacts of invading species. We test this hypothesis with European crabs in the genus Carcinus that have invaded five regions globally. Partial 16S ribosomal RNA gene sequences confirm sibling species status of morphologically similar Atlantic C. maenas and Mediterranean C. aestuarii. Based on 16S rRNA haplotypes, crabs from California, New England and Tasmania were all C. maenas. However, we report the cryptic multiple invasion of both species in Japan and South Africa, where only C. aestuarii and C. maenas, respectively, were previously recognized. 相似文献
35.
Joseph D. Geller Charles Herrington 《Journal of research of the National Institute of Standards and Technology》2002,107(6):503-508
Reducing the measurement uncertainty of quantitative analyses made using electron probe microanalyzers (EPMA) requires a careful study of the individual uncertainties from each definable step of the measurement. Those steps include measuring the incident electron beam current and voltage, knowing the angle between the electron beam and the sample (takeoff angle), collecting the emitted x rays from the sample, comparing the emitted x-ray flux to known standards (to determine the k-ratio) and transformation of the k-ratio to concentration using algorithms which includes, as a minimum, the atomic number, absorption, and fluorescence corrections.This paper discusses the collection and counting of the emitted x rays, which are diffracted into the gas flow or sealed proportional x-ray detectors. The representation of the uncertainty in the number of collected x rays collected reduces as the number of counts increase. The uncertainty of the collected signal is fully described by Poisson statistics. Increasing the number of x rays collected involves either counting longer or at a higher counting rate. Counting longer means the analysis time increases and may become excessive to get to the desired uncertainty. Instrument drift also becomes an issue. Counting at higher rates has its limitations, which are a function of the detector physics and the detecting electronics.Since the beginning of EPMA analysis, analog electronics have been used to amplify and discriminate the x-ray induced ionizations within the proportional counter. This paper will discuss the use of digital electronics for this purpose. These electronics are similar to that used for energy dispersive analysis of x rays with either Si(Li) or Ge(Li) detectors except that the shaping time constants are much smaller. 相似文献
36.
T Spencer J Biederman M Harding D O'Donnell T Wilens S Faraone B Coffey D Geller 《Canadian Metallurgical Quarterly》1998,39(7):1037-1044
OBJECTIVE: To identify similarities and differences in neuropsychiatric correlates in children with Tourette's syndrome (TS) and those with ADHD. METHOD: The sample consisted of children with Tourette's syndrome with ADHD (N = 79), children with Tourette's syndrome without ADHD (N = 18), children with ADHD (N = 563), psychiatrically referred children (N = 212), and healthy controls (N = 140). RESULTS: Disorders specifically associated with Tourette's syndrome were obsessive compulsive disorder (OCD) and simple phobias. Rates of other disorders, including other disruptive behavioral, mood, and anxiety disorders, neuropsychologic correlates, and social and school functioning were indistinguishable in children with Tourette's and ADHD. However, children with Tourette's syndrome plus ADHD had more additional comorbid disorders overall and lower psychosocial function than children with ADHD. CONCLUSIONS: These findings confirm previously noted associations between Tourette's syndrome and OCD but suggest that disruptive behavioral, mood, and anxiety disorders as well as cognitive dysfunctions may be accounted for by comorbidity with ADHD. However, Tourette's syndrome plus ADHD appears to be a more severe condition than ADHD alone. 相似文献
37.
Cockell Sarah J.; Zaitsoff Shannon L.; Geller Josie 《Canadian Metallurgical Quarterly》2004,35(5):527
Residential eating disorder treatment involves emotional, financial, and time commitments from clients, staff, and the health care system. At discharge, most clients have made substantial nutritional, social, and psychological changes. However, maintaining these changes when intensive support is no longer available represents a significant challenge, and it is common for individuals to slip back into previous eating disorder patterns. Interviews with 32 individuals were conducted 6 months after discharge. Qualitative analyses revealed a pattern of factors that facilitated and hindered recovery. These factors were integrated with past research findings to develop a conceptual model about how changes are maintained. Recommendations regarding ways that health care professionals can assist with the transition from intensive treatment to community living are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
38.
Geller J. Perl Y. Halper M. Zong Chen Huanying Gu 《IEEE transactions on information technology in biomedicine》2002,6(2):109-115
Semantic networks (SNs) are excellent knowledge representation structures. However, large semantic networks are difficult to comprehend. To overcome this difficulty, several methods of partitioning have been developed that rely on different mixes of structural and semantic methods. However, little has appeared in the literature concerning the question whether a partition of a semantic network creates subnetworks that agree with human insight. We address this issue by presenting a comparison between the results of an algorithmic partitioning method and a partition created by a group of experts. Subsequently, we show how a network partition can be used to generate various partial views of a semantic network, which facilitate user orientation. Examples from the Unified Medical Language System (UMLS) SN are used to demonstrate partial views 相似文献
39.
S Conover A Berkman A Gheith R Jahiel D Stanley PA Geller E Valencia E Susser 《Canadian Metallurgical Quarterly》1997,74(1):90-108
Public health is paying increasing attention to elusive urban populations such as the homeless, street drug users, and illegal immigrants. Yet, valid data on the health of these populations remain scarce; longitudinal research, in particular, has been hampered by poor follow-up rates. This paper reports on the follow-up methods used in two randomized clinical trials among one such population, namely, homeless men with mental illness. Each of the two trials achieved virtually complete follow-up over 18 months. The authors describe the ethnographic approach to follow-up used in these trials and elaborate its application to four components of the follow-up: training interviewers, tracking participants, administering the research office, and conducting assessments. The ethnographic follow-up method is adaptable to other studies and other settings, and may provide a replicable model for achieving high follow-up rates in urban epidemiologic studies. 相似文献
40.
Conclusions Commonness and differences in yarn structure formation by high-temperature and low-temperature stretching have been shown.Model concepts on the development of structure in high-temperature deformation during the process of high-speed yarn spinning have been examined.It has been found that, on changing the linear density of elementary filaments, the spinning speed, or the position of the lubricating device, the proportion of effective high-temperature and low-temperature deformations changes.Translated from Khimicheskie Volokna, No. 3, pp. 16–19, May–June, 1988. 相似文献