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   83篇
  免费   1篇
化学工业   7篇
金属工艺   1篇
机械仪表   1篇
建筑科学   4篇
轻工业   10篇
无线电   5篇
一般工业技术   14篇
冶金工业   36篇
原子能技术   3篇
自动化技术   3篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2019年   1篇
  2017年   1篇
  2015年   1篇
  2014年   1篇
  2011年   4篇
  2010年   3篇
  2009年   2篇
  2008年   4篇
  2007年   5篇
  2006年   5篇
  2005年   1篇
  2004年   2篇
  2003年   2篇
  2002年   3篇
  2001年   1篇
  2000年   4篇
  1998年   7篇
  1997年   2篇
  1996年   8篇
  1995年   3篇
  1993年   3篇
  1989年   3篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1981年   1篇
  1977年   1篇
  1976年   2篇
  1974年   1篇
  1972年   1篇
  1966年   2篇
排序方式: 共有84条查询结果,搜索用时 506 毫秒
41.
Objective: Depressive symptoms are associated with poor smoking cessation outcomes, and there remains continued interest in behavioral interventions that simultaneously target smoking and depressive symptomatology. In this pilot study, we examined whether a behavioral activation treatment for smoking (BATS) can enhance cessation outcomes. Method: A sample of 68 adult smokers with mildly elevated depressive symptoms (M = 43.8 years of age; 48.5% were women; 72.7% were African American) seeking smoking cessation treatment were randomized to receive either BATS paired with standard treatment (ST) smoking cessation strategies including nicotine replacement therapy (n = 35) or ST alone including nicotine replacement therapy (n = 33). BATS and ST were matched for contact time and included 8 sessions of group-based treatment. Quit date was assigned to occur at Session 4 for each treatment condition. Participants completed a baseline assessment; furthermore, measures of smoking cessation outcomes (7-day verified point-prevalence abstinence), depressive symptoms (Beck Depression Inventory–II; Beck, Steer, & Brown, 1996), and enjoyment from daily activities (Environmental Reward Observation Scale; Armento & Hopko, 2007) were obtained at 1, 4, 16, and 26 weeks post assigned quit date. Results: Across the follow-ups over 26 weeks, participants in BATS reported greater smoking abstinence (adjusted odds ratio = 3.59, 95% CI [1.22, 10.53], p = .02) than did those in ST. Participants in BATS also reported a greater reduction in depressive symptoms (B = ?1.99, SE = 0.86, p = .02) than did those in ST. Conclusions: Results suggest BATS is a promising intervention that may promote smoking cessation and improve depressive symptoms among underserved smokers of diverse backgrounds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
42.
Efficient navigation of our social world depends on the generation, interpretation, and combination of social signals within different sensory systems. However, the influence of healthy adult aging on multisensory integration of emotional stimuli remains poorly explored. This article comprises 2 studies that directly address issues of age differences on cross-modal emotional matching and explicit identification. The first study compared 25 younger adults (19–40 years) and 25 older adults (60–80 years) on their ability to match cross-modal congruent and incongruent emotional stimuli. The second study looked at performance of 20 younger (19–40) and 20 older adults (60–80) on explicit emotion identification when information was presented congruently in faces and voices or only in faces or in voices. In Study 1, older adults performed as well as younger adults on tasks in which congruent auditory and visual emotional information were presented concurrently, but there were age-related differences in matching incongruent cross-modal information. Results from Study 2 indicated that though older adults were impaired at identifying emotions from 1 modality (faces or voices alone), they benefited from congruent multisensory information as age differences were eliminated. The findings are discussed in relation to social, emotional, and cognitive changes with age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
43.
Discusses spatial abilities (SAs) in terms of sex differences in SAs, problems in individual studies, problems in the building of theories and reviews, and problems with definitions of SAs. It is noted that the notion that males are superior to females in the performance of spatial tasks has been widely accepted. However, serious problems exist in this area in terms of the generally small size and inconsistency of sex differences, difficulties in individual studies, and in 2 types of reviews of the research (the lack of consensus about definition and the paucity of evidence that the construct of SAs is legitimate). Because of these problems, particularly those related to the construct, it is argued that the conclusion that males are superior is unwarranted. The fundamental issue of the legitimacy of the construct is discussed. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
44.
Experiments have been performed with 19- and 61-pin test assemblies in the Thermal-Hydraulic Out-of-Reactor Safety (THORS) Facility at the Oak Ridge National Laboratory (ORNL) since 1971. The THORS Facility is a high-temperature sodium system operated for the US Liquid-Metal Fast Breeder Reactor (LMFBR) Safety Program. The facility is used primarily for testing simulated LMFBR fuel subassemblies (pin (bundles). High-performance, electrically heated fuel pin simulators (FPSs) duplicate the heat generating capabilities and the dimensional characteristics of the nuclear fuel pins. A number of test bundles have been built and operated to obtain base thermal-hydraulic data, inlet and heated zone blockage data, and transient boiling data. Five of these bundles have been operated under two-phase conditions. Sodium boiling for periods up to twelve minutes were sustained in one bundle. (The lengths of the periods were limited only by automatic data recording capability). Clad dryout occurred in several tests. Tests were run at widely varying conditions of flow and power density. Testing with nonuniform power distribution across the bundle was also a part of the program.A 19-pin bundle with 12 peripheral guard heaters and a 6-subchannel blockage around the center pin in the heated zone was tested. The test program for this bundle was designed to determine if local boiling in the wake of the blockage propagates radially or axially during quasi-steady-state conditions. Post-test inspection revealed that significant helical distortion of the FPSs occurred in the vicinity of the blockage plate. This distortion probably influenced the boiling behavior. In the more severe tests, boiling initiated at the outlet of the heated zone and propagated radially into the unblocked subchannels after it had progressed upstream to the blockage. The subchannel analysis codes, SABRE and COBRA, accurately predict the extent of the boiling region.Experimental and analytical studies of sodium boiling behavior in unblocked 19- and 61-pin bundles indicate that cooling can be maintained for a significant period of time beyond boiling inception in a flow-power transient. Quasi-steady-state boiling occurred under natural-convection conditions.Investigations of the temperature data indicate that the thermal-hydraulic behavior during boiling transients is determined by two-dimensional effects, and that one-dimensional models cannot accurately predict the important phenomena associated with sodium boiling in test bundles. The subchannel code SABRE-2P (with a simple two-phase multiplier boiling model) and the two-region equilibrium mixture code THORAX (developed at ORNL) accurately predict the two-dimensional behavior between boiling inception and dryout.Extrapolation of the data from the smaller bundle tests to full-size fuel assemblies shows that the time between boiling inception and dryout would be lower for a 217-pin bundle than for a 61-pin bundle for a comparable transient. However, the time delay would still be significant, especially in a heterogeneous reactor core.  相似文献   
45.
Higher spatial resolution in Earth–atmosphere models requires improved information on surface fields with very different thermal characteristics, such as land and water. Remote sensing is a useful tool for this purpose. A method is presented here to determine and compare the temperature evolution of water bodies. Thermal IR observations were extracted from NOAA's advanced very high-resolution radiometer (AVHRR) satellite data over the period from April 1 to August 31, 1994. The IR temperatures were calibrated and adjusted to account for the intervening atmosphere. For each day, 1-km resolution temperature scenes were generated for a 1000×1000-km rectangular region extending from about 60°N, 111°W over the northern part of the Canadian Province of Alberta to about 50°N, 97°W in southern Manitoba. There are 132 water bodies of area larger than 100 km2 in this study area. The temperature cycle over these water bodies can be decomposed into a straight line with a small positive slope for spring ice break-up, followed by a fitted quadratic curve for the summer temperature variations. The curve fit parameters give information on the transition between ice and ice-free conditions. Data stratification confirms a strong latitudinal influence on the shape of the curves. It was not possible to quantify the effect of water depth, as the depth of most boreal lakes is not known. Instead, a list of fit coefficients for all the water bodies is provided. Once detrended from the quadratic curves, the amplitude of the diurnal cycle and major variations in temperatures of the water bodies can be determined. The detrended water temperature variations are about one-third the magnitude of the detrended air temperature variations from nearby weather stations.  相似文献   
46.
A procedure is described for estimating the free fatty acids in wort and beer by gas liquid chromatography. The free fatty acids with carbon number 8 to 18 are estimated simultaneously from one injection, and by including two internal standards the reproducibility of the method is maintained over the whole range. It has been demonstrated that other lipid materials such as glycerides and esters of fatty acids do not interfere with the assay. Compared with other methods, this procedure is fairly rapid and is suitable for routine purposes. The reproducibility of the method has been assessed by analysing replicate samples of wort and beer and the precision in estimating individual fatty acids is given.  相似文献   
47.
We describe the characterization of the temperature and strain responses of fiber Bragg grating sensors by use of an interferometric interrogation technique to provide an absolute measurement of the grating wavelength. The fiber Bragg grating temperature response was found to be nonlinear over the temperature range -70 degrees C to 80 degrees C. The nonlinearity was observed to be a quadratic function of temperature, arising from the linear dependence on temperature of the thermo-optic coefficient of silica glass over this range, and is in good agreement with a theoretical model.  相似文献   
48.
This study was designed to evaluate whether hair calcium concentration reflects the mortality from coronary heart disease on a UK-wide basis and to determine the effect--if any--of environmental factors which might affect calcium metabolism on this relationship. The study was based on our earlier findings of an inverse relationship between hair calcium concentration and that in the intima of the aorta and the association of high aorta calcium with severe alterations to the vessel walls which was found never to co-exist with hair calcium concentrations greater than 700 ppm. Hair samples were collected from 4393 males in an ethically approved study in 40 different health districts. These covered the range in known prevalence of heart disease as reflected in the published standardised mortality ratios (SMR). Data on water hardness were obtained from the Water Authorities and on mean annual sunshine hours from the Meteorological Office. Statistical analysis was by regression and multivariate regression techniques. Hair calcium was determined by XRF analysis and the accuracy validated by means of certified reference samples. Significant relationships were found between health district and county SMR and their respective mean hair calcium concentrations accounting for 37 and 55% of their respective variances in SMR. Water hardness and sunshine hours accounted for 39 and 49% of the variance in mortality from CHD. In combination they accounted for 54% of the variance and with the inclusion of hair calcium 65%. South-east England had the highest hair calcium, the hardest water and the most sunshine hours and the lowest mortality from CHD. The converse was true of Scotland. Hair calcium concentration did reflect the risk of CHD on a population basis and was strongly influenced by both the hardness of the water supply and the annual sunshine hours which also independently affected the SMR for CHD.  相似文献   
49.
Invasive aspergillosis (IA) is a life-threatening fungal disease that causes high morbidity and mortality in immunosuppressed patients. Early and accurate diagnosis and treatment of IA remain challenging. Given the broad range of non-specific clinical symptoms and the shortcomings of current diagnostic techniques, most patients are either diagnosed as “possible” or “probable” cases but not “proven”. Moreover, because of the lack of sensitive and specific tests, many high-risk patients receive an empirical therapy or a prolonged treatment of high-priced antifungal agents, leading to unnecessary adverse effects and a high risk of drug resistance. More precise diagnostic techniques alongside a targeted antifungal treatment are fundamental requirements for reducing the morbidity and mortality of IA. Monoclonal antibodies (mAbs) with high specificity in targeting the corresponding antigen(s) may have the potential to improve diagnostic tests and form the basis for novel IA treatments. This review summarizes the up-to-date application of mAb-based approaches in assisting IA diagnosis and therapy.  相似文献   
50.
Cavities have been laser ablated in the ends of single-mode optical fibers and sealed by aluminized polycarbonate diaphragms to produce Fabry-Perot pressure sensors. Both conventional fibers and novel, multicore fibers were used, demonstrating the possibility of producing compact arrays of sensors and multiple sensors on an individual fiber 125 microm in diameter. This high spatial resolution can be combined with high temporal resolution by simultaneously interrogating the sensors by using separate laser sources at three wavelengths. Shock tube tests showed a sensor response time of 3 micros to a step increase in pressure.  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