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31.
Continuing growth in electric motor size is coupled with greater need for reliable interconnection between motor and power system to minimize process downtime. Yet the many standards governing electrical clearance, moisture resistance, grounding, safety, and cooling of electrical apparatus have little to say about that interconnection located within the motor terminal box. The traditional bolted and taped terminal lug joints, requiring long hours of skilled labor to make up, need remaking each time the circuit must be opened for testing or motor servicing. The high-voltage separable connector, forming a watertight, yet easily removable joint at low cost, now offers a suitable alternative if its limitations are fully understood.  相似文献   
32.
The water "stripes" of the TOCSY maps of aqueous solutions of sucrose, of a 15-aminoacid peptide, and of several of the constituent aminoacids are shown to contain correlations at the resonance frequencies of protons which are scalar coupled to OH or NH protons which exchange with the solvent. Theoretical analysis of chemical exchange during the spin-lock period in TOCSY elucidates the origin of these correlations, and shows that their intensities vary with the duration of the spin-lock period and with the exchange rate.  相似文献   
33.
The inelastic deformation behavior of PMR‐15 neat resin, a high‐temperature thermoset polymer, aged at 288°C in argon environment for up to 2000 h was investigated. The experimental program was designed to explore the in?uence of prior isothermal aging on monotonic loading and unloading at various strain rates. In addition, the relaxation response and the creep behavior of specimens subjected to prior aging of various durations were evaluated. All tests were performed at 288°C. The time‐dependent mechanical behavior of the PMR‐15 polymer is strongly influenced by prior isothermal aging. The elastic modulus increased and the departure from quasi‐linear behavior was delayed with prior aging time. Stress levels in the region of inelastic flow increased with prior aging time. Furthermore, prior aging significantly decreased the polymer's capacity for inelastic straining, including the material's capacity to accumulate creep strain. Conversely, the relaxation response was not affected by the prior aging. © 2009 Wiley Periodicals, Inc.? J Appl Polym Sci, 2009  相似文献   
34.
This article details a series of website usability studies conducted by librarians at Fresno State in collaboration with faculty and students from the university's anthropology department. Building on an ethnographic study of the library, we sought to understand how students used the site. Collaboration with individuals outside the library allowed us to use their expertise in behavioral research, accomplish a larger series of studies, and redesign the website from a less library-centric perspective. In this article, we detail the study's genesis, methodology, results, and offer our experiences using a large-scale usability test to drive changes to an academic library website.  相似文献   
35.
Rice bran chemical profiles differ across rice varieties and have not yet been analysed for differential chemopreventive bioactivity. A diverse panel of seven rice bran varieties was analysed for growth inhibition of human colorectal cancer (CRC) cells. Inhibition varied from 0% to 99%, depending on the variety of bran used. Across varieties, total lipid content ranged 5–16%, individual fatty acids had 1.4- to 1.9-fold differences, vitamin E isoforms (α-, γ-, δ-tocotrienols, and tocopherols) showed 1.3- to 15.2-fold differences, and differences in γ-oryzanol and total phenolics ranged between 100–275 ng/mg and 57–146 ng GAE/mg, respectively. Spearman correlation analysis was used to identify bioactive compounds implicated in CRC cell growth inhibitory activity. Total phenolics and γ-tocotrienol were positively correlated with reduced CRC cell growth (p < 0.05). Stoichiometric variation in rice bran components and differential effects on CRC viability merit further evaluation elucidate their role in dietary CRC chemoprevention.  相似文献   
36.
Abstract: Dietary starches can be classified into 3 major fractions according to in vitro digestibility as rapidly digestible (RDS), slowly digestible (SDS), and resistant starch (RS). Literature indicates that SDS and/or RS have significant implications on human health, particularly glucose metabolism, diabetes management, colon cancer prevention, mental performance, and satiety. In this study, the nutritionally important starch fractions (RDS, SDS, and RS) in cooked rice were assayed in vitro, making use of 16 cultivars grown in 5 southern U.S. rice growing locations (Arkansas, Louisiana, Mississippi, Missouri, and Texas). RDS, SDS, and RS were 52.4% to 69.4%, 10.3% to 26.6%, and 1.2% to 9.0%, respectively, of cooked rice dry weight. Cultivar, location, and cultivar-by-location interaction contributed to the variations in RDS, SDS, and RS contents. Means pooled across locations indicated that SDS was higher for the Louisiana samples than those from Texas, whereas RS was higher for the Texas samples than those from Arkansas, Louisiana, and Mississippi. Some cultivars were identified to possess high levels of RS (for example, Bowman and Rondo) or SDS (for example, Dixiebelle and Tesanai-2) and were also stable across growing locations. Apparent amylose content correlated positively with RS (n = 80, r = 0.54, P ≤ 0.001), negatively with RDS (n = 80, r =−0.29, P ≤ 0.05), and insignificantly with SDS (n = 80, r = 0.21, P > 0.05). RS and SDS were not collinear (n = 80, r =−0.18, P > 0.05); it does not follow that a cultivar high in RS will also be high in SDS, and vice versa. The observed differences in RDS, SDS, and RS among the samples are indicative of wide genetic diversity in rice.  相似文献   
37.
Abstract— Elastic-plastic finite element analysis is used to study fatigue crack closure at three different crack length to width ratios for three plane stress specimen geometries: center-cracked plate, single-edge-cracked plate (tension), and single-edge-cracked plate (bend). The maximum stress to flow stress ratio, SmaxO, which successfully describes closure results in many center-cracked plate configurations, does not correlate the effect of different geometries on the normalized opening stress, S open/ S max. Crack opening stresses for different geometries and crack lengths are successfully correlated by a normalized stress intensity parameter, K max/ K 0, where K 00φa. The quality of the correlation is very high at small K max/ K 0, and gradually deteriorates as K max/ K 0 increases beyond the small-scale yielding regime.  相似文献   
38.
The hip axis length has been shown in previous studies to be predictive of hip fracture independent of age and femoral bone density. The first studies of hip axis length were performed by manual measurement of dual x-ray absorptiometry (DXA) scan printouts. In this study, an automated analysis procedure is defined using software tools provided by the DXA manufacturer. Manual and automatic hip axis length measurements in 198 women were highly correlated (r = 0.98). Because of scaling factors of the printout, the automatic measurement was 58% longer than the manual value. Precision of the automatic measurement, based upon triplicate DXA scans of 33 women, was 0.07 cm or 0.68%. To define normative data, the hip axis length was measured from femoral DXA scans of 471 female volunteers aged 40-92 scanned on 14 different Hologic QDR-1000 systems. Mean hip axis length was 10.5 cm, with a standard deviation of 0.62 cm. No significant relationship between hip axis length and age was found (r = 0.07, P = 0.15). Based on previously reported odds ratios corrected for femoral bone density, age, height, and weight, an automatic hip axis length measurement of 11.0 cm is associated with a twofold increase in hip fracture risk compared with a woman with an average hip axis length. A hip axis length value of 11.6 cm increases hip fracture risk by a factor of 4 compared with a woman with a normal hip dimension. We conclude that the hip axis length can be easily incorporated into existing DXA hip analysis software in combination with a bone density measurement.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
39.
To extend previous cognition-based illegal downloading research, this project postulates that anticipated guilt, general emotions, attitudes, and norms collectively determine intentions to download digital files illegally. Our findings indicate that college students were more likely to download if they had more favorable attitudes, perceived greater social approval, and perceived more control over illegal downloading. More importantly, this study reveals that college students generally felt a low level of anticipated guilt toward illegal downloading. Anticipated guilt was a significant, negative predictor of intentions to download among those who engaged in illegal downloading in the previous 6 months, but not among those did not. General anticipated emotions predicted intentions to download among the whole sample. Both theoretical and practical implications are discussed.  相似文献   
40.
CRACK CLOSURE AND PLASTIC ZONE SIZES IN FATIGUE   总被引:2,自引:0,他引:2  
Abstract— An elastic-plastic finite element simulation of growing fatigue cracks which accounts for plasticity-induced crack closure is used to study the size of the forward and reversed plastic zones at the crack tip. Forward plastic zone widths for fatigue cracks and stationary, monotonically loaded cracks are compared and found to be similar. The width of the forward plastic zone at the tip of a fatigue crack is not significantly influenced by closure. The traditional Irwin-Rice estimate for crack tip plastic zone size in plane stress is found to be generally consistent with the finite element results. The width of the reversed plastic zone at the tip of a growing fatigue crack in plane stress is found to be considerably less than one-fourth the size of the forward plastic zone, the traditional Rice estimate. This decrease appears to be due to fatigue crack closure. A simple model is developed which permits estimation of the reversed plastic zone size for any stress ratio from information about maximum and minimum stresses and the closure stress. The predictions of this model agree closely with plastic zone sizes calculated by the finite element analysis. These observations appear to be consistent with experimental measurements of forward and reversed plastic zones sizes reported in the literature.  相似文献   
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