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排序方式: 共有220条查询结果,搜索用时 12 毫秒
31.
PURPOSE: A new dietary zinc assessment tool (ZAT) was evaluated to determine its usefulness in estimating zinc intakes among college students. METHODS: A food frequency questionnaire specifically designed for calculating average zinc intakes was administered to university students who had also completed three-day food records. Zinc intakes from the two instruments were compared. RESULTS: Among 171 participants (38 male, 133 female) aged 20.2 +/- 1.6 years (mean +/- standard deviation), the two dietary assessment methods were positively correlated (r=0.33, p<0.001). The ZAT correctly identified 76% of the women who were obtaining less than the National Academy of Sciences Recommended Dietary Allowance for zinc (8 mg/day for females, 11 mg/day for males). CONCLUSIONS: This convenient tool may assist in the identification of problematic dietary patterns at an early stage. Further design modifications and expanded studies are warranted. 相似文献
32.
The static and dynamic stiffnesses of spindle-bearing systems are examined. It is shown that for most general purpose spindle designs spring or hydraulically preloaded bearing arrangements can produce more rigid spindles than comentational bearing arrangements. It is also argued that adjustable preload enables bearing damping to be matched to the spindle-bearing system to give maximum dynamic stiffness. The RHP Variload bearing arrangement is introduced. 相似文献
33.
Lobel Marci; Cannella Dolores Lacey; Graham Jennifer E.; DeVincent Carla; Schneider Jayne; Meyer Bruce A. 《Canadian Metallurgical Quarterly》2008,27(5):604
Objective: Stress in pregnancy predicts earlier birth and lower birth weight. The authors investigated whether pregnancy-specific stress contributes uniquely to birth outcomes compared with general stress, and whether prenatal health behaviors explain this association. Design: Three structured prenatal interviews (N = 279) assessing state anxiety, perceived stress, life events, pregnancy-specific stress, and health behaviors. Main Outcome Measures: Gestational age at delivery, birth weight, preterm delivery ( 相似文献
34.
CJ Lacey HS Thompson EF Monteiro T O'Neill ML Davies FP Holding RE Fallon JS Roberts 《Canadian Metallurgical Quarterly》1999,179(3):612-618
A fusion protein vaccine consisting of human papillomavirus 6 L2E7 with Alhydrogel was developed for the treatment of genital warts. Twenty-seven subjects with genital warts received 3 immunizations over 4 weeks in an open-label study. The vaccine was well-tolerated, and all subjects made serum IgG antibodies, predominantly IgG1, against L2E7. Nineteen of 25 tested persons made antigen-specific T cell proliferative responses to L2E7, and peripheral blood mononuclear cells when cultured with L2E7 in vitro produced both interferon-gamma and interleukin (IL)-5, although IL-5 predominated after the final vaccination. Five subjects completely cleared warts within 8 weeks. Subjects whose warts were not cleared by 8 weeks were offered conventional therapy. Recurrence of warts was not seen in any of the 13 persons whose warts cleared by vaccine alone or with conventional therapy. While these preliminary results of the use of this therapeutic immunogen are encouraging, proof of efficacy will require randomized double-blind trials. 相似文献
35.
Hanks LM Millar JG Moreira JA Barbour JD Lacey ES McElfresh JS Reuter FR Ray AM 《Journal of chemical ecology》2007,33(5):889-907
Males of several species of longhorned beetles in the subfamily Cerambycinae produce sex or aggregation pheromones consisting
of 2,3-hexanediols and/or hydroxyhexanones. We tested the hypothesis that this diol/hydroxyketone pheromone motif is highly
conserved within the subfamily, and the resulting prediction that multiple cerambycine species will be attracted to compounds
of this type. We also tested the concept that live traps baited with generic blends of these compounds could be used as a
source of live insects from which pheromones could be collected and identified. Traps placed in a mature oak woodland and
baited with generic blends of racemic 2-hydroxyhexan-3-one and 3-hydroxyhexan-2-one captured adults of both sexes of three
cerambycine species: Xylotrechus nauticus (Mannerheim), Phymatodes lecontei Linsley, and Phymatodes decussatus decussatus (LeConte). Odors collected from male X. nauticus contained a 9:1 ratio of two male-specific compounds, (R)- and (S)-3-hydroxyhexan-2-one. Field trials with synthetic compounds determined that traps baited with (R)-3-hydroxyhexan-2-one (94% ee), alone or in blends with other isomers, attracted similar numbers of X. nauticus of both sexes, whereas (S)-3-hydroxyhexan-2-one (94% ee) attracted significantly fewer beetles. Phymatodes lecontei and P. d. decussatus also were caught in traps baited with hydroxyhexanones, as well as a few specimens of two other cerambycine species, Neoclytus modestus modestus Fall (both sexes) and Brothylus gemmulatus LeConte (only females). Male N. m. modestus produced (R)-3-hydroxyhexan-2-one, which was not present in extracts from females. Neoclytus m. modestus of both sexes also responded to lures that included (R)-3-hydroxyhexan-2-one as one of the components. The only male-specific compound found in extracts from P. lecontei was (R)-2-methylbutan-1-ol, and adults of both sexes were attracted to racemic 2-methylbutan-1-ol in field bioassays. Surprisingly,
P. lecontei of both sexes also were attracted to (R)- and (S)-3-hydroxyhexan-2-ones, although neither compound was detected in extracts from this species. Males of all five beetle species
had gland pores on their prothoraces that were similar in structure to those that have been associated with volatile pheromone
production in other cerambycine species. The attraction of multiple cerambycine species of two tribes to (R)-3-hydroxyhexan-2-one in this study, and in earlier studies with other cerambycine species, suggests that this compound is
a widespread aggregation pheromone component in this large and diverse subfamily. Overall, the attraction of multiple species
from different cerambycine tribes to this compound at a single field site supports the hypothesis that the hydroxyketone pheromone
structural motif is highly conserved within this subfamily. 相似文献
36.
Sillam-Dussès D Sémon E Lacey MJ Robert A Lenz M Bordereau C 《Journal of chemical ecology》2007,33(10):1960-1977
In the framework of an evolutionary study, trail pheromones have been studied in the most basal extant termite, Mastotermes darwiniensis (Mastotermitidae), and two other basal termites, the Termopsidae Porotermes adamsoni (Porotermitinae) and Stolotermes victoriensis (Stolotermitinae). Although workers of M. darwiniensis do not walk in single file while exploring a new environment under experimental conditions and are unable to follow artificial
trails in ‘open field’ experiments, they do secrete a trail-following pheromone from their sternal glands. This unique behavior
might reflect a primitive function of communication of the sternal gland. The major component of the pheromone appears to
be the same in the three basal species: the norsesquiterpene alcohol (E)-2,6,10-trimethyl-5,9-undecadien-1-ol. This represents a new chemical category of trail-following pheromones for termites.
The quantity of pheromone was estimated as 20 pg/individual in M. darwiniensis, 700 pg/individual in P. adamsoni, and 4 pg/individual in S. victoriensis. The activity threshold was 1 ng/cm in M. darwiniensis and 10 pg/cm in P. adamsoni. In M. darwiniensis, the trail pheromone was secreted by sternal gland 4 and to a lesser degree by sternal gland 3, sternal gland 5 being almost
inactive. This study highlighted phylogenetic relationships between the Mastotermitidae and two subfamilies of the Termopsidae,
the Porotermitinae and the Stolotermitinae. Furthermore, it indicated a heterogeneity within the Termopsidae, with Porotermitinae
and Stolotermitinae on one hand, and Termopsinae on the other. Finally, Mastotermitidae and Termopsidae, with C14 trail pheromones,
are clearly separated from the Kalotermitidae, Rhinotermitidae, and Termitidae that secrete C12 or C20 trail pheromones. 相似文献
37.
Judy M. Watson Paul M. Salmon David Lacey Don Kerr 《Theoretical Issues in Ergonomics Science》2013,14(6):637-657
ABSTRACTThis paper presents findings from a literature review on older adults continued use of the Internet following an identity theft incident. Globally, identity theft is increasing, statistics show that the number of older adults falling victim to identity theft is growing. Victims of identity theft suffer emotional, physical, psychological, and social problems; many change their behaviour as a result. The aim of the review was to examine literature to determine what is known regarding how older adults use the Internet and/or modify their online behaviour following an identity theft event. It was found that knowledge is lacking regarding the impact that identity theft events have on older adults’ continuation of Internet use. Little research has been undertaken to understand the factors and interrelationships that contribute to the situation. The review highlights that a systems ergonomics approach should be considered as an appropriate framework to drive future research in this area. 相似文献
38.
Attenuated total reflection (ATR) spectroscopy is now the most popular sampling technique for the measurement of infrared spectra of condensed phase samples. Most practitioners of ATR spectroscopy use the equation for depth of penetration, d(p), to estimate the path length of the evanescent wave through the sample. However, the effective path length, d(e), of the evanescent wave in an ATR measurement, i.e., the equivalent path length in a transmission measurement that would lead to an absorption band of the same intensity, is a more accurate metric than d(p). In measurements designed to obtain the absorptivity of bands in the spectrum of a strongly absorbing viscous liquid, we have shown that the refractive index used in the expressions for d(e) must be modified to take into account the effect of anomalous dispersion before accurate effective path lengths and band absorptivities can be measured. 相似文献
39.
The average total path length traveled by photons in mid-infrared diffuse reflection spectrometry of powdered potassium chloride matrices coated with a thin layer of silicone oil has been estimated. The average path length of the photons that had passed through the silicone oil layer was first calculated by the application of the Beer-Lambert law. The total path length through the coated particles was then estimated by dividing the path length of the silicone oil by its concentration. The average path length of the photons that had been diffusely reflected from KCl particles with an average diameter of approximately 5 microm that had been coated with a very thin layer of the silicone oil (corresponding to a concentration of 0.01% w:w) was estimated to be about 8 mm. This path length was significantly reduced either as the silicone oil concentration or the absorption of the matrix was increased. The result helps to explain why diffuse reflection spectrometry is a far poorer sampling technique for trace analysis when the matrix has strong absorption and why diffuse reflection is not a very promising technique for the standoff detection of nonvolatile chemical warfare agents. 相似文献
40.
Abstract The paper considers economic effects of increased investment in public transport in Melbourne, based on investment plans of VicRail and the M.M.T.B. over a 5 year period, 1981–5. If the investment were to encourage a shift in patronage from private to public transport, this would change the magnitude of costs associated with passenger transport in Melbourne. Calculations are made of these possible cost savings, given particular levels of shift in patronage. The paper concludes by reviewing the feasibility of achieving given patronage changes. 相似文献