全文获取类型
收费全文 | 130篇 |
免费 | 1篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 43篇 |
机械仪表 | 1篇 |
建筑科学 | 2篇 |
能源动力 | 5篇 |
轻工业 | 6篇 |
无线电 | 13篇 |
一般工业技术 | 11篇 |
冶金工业 | 37篇 |
自动化技术 | 12篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 1篇 |
2005年 | 2篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 9篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1967年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有131条查询结果,搜索用时 453 毫秒
51.
In this study, we sampled sworn police officers from three law enforcement agencies (n = 452), each of which had different system responses to mentally ill people in crisis. One department relies on field assistance from a mobile mental health crisis team, a second has a team of officers specially trained in crisis intervention and management of mentally ill people in crisis, and a third has a team of in-house social workers to assist in responding to calls. Calls involving mentally ill people in crisis appear to be frequent and are perceived by most of the officers to pose a significant problem for the department; however, most officers reported feeling well prepared to handle these calls. Generally, officers from the jurisdiction with a specialized team of officers rated their program as being highly effective in meeting the needs of mentally ill people in crisis, keeping mentally ill people out of jail, minimizing the amount of time officers spend on these calls, and maintaining community safety. Officers from departments relying on a mobile crisis unit (MCU) and on police-based social workers both rated their programs as being moderately effective on each of these dimensions except for minimizing officer time on these calls where the MCU had significantly lower ratings. 相似文献
52.
53.
Berlin Irving N.; Critchley Deane L.; Rossman Paul G. 《Canadian Metallurgical Quarterly》1984,21(1):118
In a variety of treatment settings, a therapeutic milieu provides intensive psychotherapeutic and psychoeducational experiences for disturbed children and young adolescents. It is generally agreed that effective psychosocial treatment requires a developmentally based treatment approach, collaborative parental involvement, and provision for ongoing staff support and training. In such settings, the treatment plan for each child reflects developmental, psychosocial, biological, cognitive, and neurointegrative aspects of the child's problems and identifies specific roles for psychotherapists, caseworkers, educators, occupational and recreational therapists, and parents (Alt, 1961; Pfeffer, 1979; Redl, 1959; Trieschman, 1969). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
54.
Deane R. Blackman 《Cryptologia》2013,37(1):53-54
ABSTRACT This note shows that the cams in the Geheimschreiber could be installed in a reversed position and provides support for the contention that the same cam set was used in all models of the machine. 相似文献
55.
Plants produce a variety of secondary metabolites that function as a defense against their natural enemies. Production of these secondary metabolites is genetically controlled, but is also phenotypically plastic and varies in response to both biotic and abiotic factors. Therefore, plant species may vary widely in their chemical defenses and such variation can be evident at temporal, spatial and tissue levels. Focusing on the chemical defenses of a native Colorado wildflower, Penstemon virgatus, we assessed the variation in iridoid glycoside (IG) content across two non-consecutive growing seasons, six natural populations and three tissue types: leaves, stems and flowers. Our results indicate that P. virgatus plants contain high concentrations of IGs (mean = 23.36% dry weight of leaves) and that IGs were differentially allocated among tissue types. Leaves contained the highest concentration of IGs, which varied quantitatively between sampling years, among plant populations, and plant parts. We also quantified leaf herbivore damage at all six populations but we found very little herbivore damage. Our study indicates that the IG concentrations of P. virgatus plants are both spatially and temporally variable. Furthermore, the high concentrations of secondary metabolites combined with the low levels of damage suggest that these plants are well defended against generalist herbivores. 相似文献
56.
The use of poly(phenylene oxide) film to monitor UV radiation is demonstrated, and the results from the continuous monitoring of solar UV radiation at 24 sites throughout the world are presented. The global and diffuse measurements from a temperate and from a tropical site are analyzed in detail, and the effects of season and weather conditions on the UV contribution to solar radiation and the relative importance of the diffuse and direct components of solar UV are discussed. 相似文献
57.
The lycaenid butterfly,Eumaeus atala, was found to contain cycasin, an azoxyglycoside, by thin-layer chromatography (TLC). Quantification of cycasin content in 10 individual freshly killed and frozen males and females, using capillary gas chromatography (GC), showed that cycasin contents of individual butterflies ranged from 0.21 to 0.51 mg (1.24–2.75% dry weight). A museum specimen ofE. atala of unknown age had undetectable amounts of cycasin by GC. GC showed that larval frass contained about 0.10% cycasin, which was not detectable by TLC. Cycasin in the host plant was not detectable by TLC but was detected by GC and found to be 0.02% dry weight. There was no macrozamin, another azoxyglycoside characteristic of many cycads, in the butterfly or plant. Feeding trials with a colony of the ant,Camponotus abdominalis floridanus, showed that both cycasin and the adult ofE. atala were deterrent to the ants. 相似文献
58.
The buckeye butterfly,Junonia coenia (Lepidoptera: Nymphalidae), specializes on plants that contain iridoid glycosides. To determine the fate of these compounds in larvae, pupae, and adults of this species, we reared larvae on artificial diets with and without iridoid glycosides, and on leaves of a host plant,Plantago lanceolata (Plantaginaceae). Quantification by gas chromatography showed that newly molted third-, fourth-, and fifth-instar larvae reared on leaves ofP. lanceolata contained means of 5.13, 2.88, and 6.83% dry weight iridoid glycoside. In contrast, the mean iridoid glycoside concentration of actively feeding fifth-instar larvae was 0.28% dry weight, that of pupae was 0.19% dry weight iridoids, and adults contained no detectable iridoids. Feeding experiments suggested that this reduction in actively feeding larvae was due to the metabolism of iridoid glycosides.P. lanceolata leaves in these experiments contained a mean of 1.00% dry weight iridoid glycoside, with a 2:1 ratio of aucubin to catalpol. Calculation of iridoid consumption and utilization indices showed that larvae fed artificial diets consumed, digested, and sequestered aucubin and catalpol in similar ways. When these indices were calculated for larvae fed leaves ofP. lanceolata, catalpol was sequestered twice as efficiently as aucubin. 相似文献
59.
We reared larvae ofJunonia coenia Hubner (Nymphalidae) on artificial diets with trace concentrations of iridoid glycosides and on leaf diets with higher concentrations of iridoid glycosides. We offered these caterpillars to predacious ants and observed the effects of the following on predation: diet (artificial vs. leaf), site (ant colonies in dry vs. wet areas), instar (early vs. late), and time (changes in predation over five days). Diet and site were consistently significant predictors of the ants' propensities to reject prey and the caterpillars' abilities to escape predation. Leaf-diet caterpillars escaped more frequently than artificial-diet caterpillars, and ants from dry sites were more likely to reject prey than ants from wet sites. The percentage of iridoid glycosides found in individual caterpillars was also a good predictor of the probability of rejection by predators and prey escape. Caterpillars with higher levels of iridoids were more likely to be rejected and to escape, suggesting that sequestered iridoid glycosides are a defense against predaceous ants. 相似文献