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91.
Environmental stress and recovery: the geochemical record of human disturbance in New Bedford Harbor and Apponagansett Bay,Massachusetts (USA) 总被引:1,自引:0,他引:1
Latimer JS Boothman WS Pesch CE Chmura GL Pospelova V Jayaraman S 《The Science of the total environment》2003,313(1-3):153-176
Sediments record the history of contamination to estuaries. Analysis of the concentrations of toxic organic compounds, contaminant and crustal metals, organic carbon content and isotopic composition in sediment cores from two estuarine systems in Buzzards Bay allowed reconstruction of human impacts over 350 years. Vertical distributions of the contaminants correlate with changes in the nature of watershed/estuarine activities. All contaminants were highly enriched (tens to hundreds times background) in modern New Bedford Harbor sediments. Enrichment began around the turn of the 20th century for all but PCBs, which were first synthesized in the 1930s. An increase in organic carbon content and a shift of carbon isotopes toward a more terrestrial signature illustrates increasing anthropogenic impact in New Bedford as population grew along with the industrial base. Institution of environmental protection measures in the late 20th century was reflected in decreased, although still substantially elevated, concentrations of contaminants. A lack of industrial development in Apponagansett Bay resulted in much lower concentrations of the same indicators, although specific contaminants related to the early whaling industry increased significantly above background as early as the late 18th century. The similarity of indicators in older portions of cores from NBH and unimpacted Apponagansett Bay demonstrates that cores can be used to establish reference conditions as successfully as using separate sites judged a priori to represent the reference state. The historical reconstruction approach provides the basis for establishing relationships between environmental stressors and factors that drive the stressors, as well as a framework for the assessment of ecological response(s) to environmental stressors over a range of time and/or exposure scales. 相似文献
92.
An unsedated dog model of bronchial mucociliary clearance was developed using radioaerosol techniques. A neutralized, concentrated, monodisperse iron oxide aerosol (5–6 μm MMAD) radiotagged with technetium-99m was delivered to the dog via a face mask. Retained activity was measured while the dog was restrained in front of a gamma camera. Measurements were made for 2–3 h post-inhalation and again at 24 h. Three beagle dogs, each studied four times, demonstrated mean percents for 2 h particle retention within the whole lung of 76 ± 13, 92 ± 7 and 89 ± 4, within the bronchial airways of 48 ± 27, 84 ± 15 and 73 ± 10, and mean 24 h particle retentions of 47 ± 18, 65 ± 11 and 57 ± 9, respectively. The unsedated beagle dog provides a potential model for study of the effects of drugs, disease and inhaled pollutants on mucociliary transport. 相似文献
93.
Examined the adequacy of L. Kohlberg's (1971) cognitive-developmental model as a representation of female moral reasoning. Specifically, the claims of C. Gilligan (1982) that there are 2 conceptions of morality—one described as a morality of justice, on which Kohlberg's scheme is based, and one described as a morality of care, seen by Gilligan as more representative of female thinking about moral conflict—were studied. 101 male and 101 female undergraduates filled out a self-report questionnaire on moral dilemmas they had experienced. They then rated their use of both justice and care orientations in resolving those dilemmas. Ss also completed the Interpersonal Disposition Inventory and semantic differential items. The use of the 2 orientations was examined in relationship to S gender, sex role, and perceptions of the 2 orientations. Few significant differences were obtained, except that female Ss were more consistent in their use of a care orientation and male Ss were more consistent in their use of a justice orientation. More feminine males were more likely to report the use of a care orientation than less feminine males. Male and female reasoning about moral conflict is examined in the light of these 2 perspectives, and the relationship of sex roles to endorsement of each perspective is discussed. (23 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
94.
This study examined the contributions of four individual difference predictors to preschool children's recall for object names. Measures of object knowledge (the Peabody Picture Vocabulary Test [PPVT]), conceptual tempo (the Kansas Reflection-Impulsivity Scale for Preschoolers [KRISP] error scores), strategic study period activities, and teacher ratings of children's mastery motivation were used to predict recall scores of 3- and 4-year-old children. KRISP-error scores, strategic study activities, and motivation ratings were found to be significant correlates of recall. Motivation ratings entered a regression prediction equation first, followed by the strategic study activity measure, yielding a multiple correlation of .62. These predictors were unrelated, suggesting that motivational factors contributed to young children's recall proficiency directly, perhaps through greater task involvement and analysis and more effortful retrieval activity, and do not mediate strategic study behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
95.
Carol L. Haertling Shoko Yoshikawa Robert E. Newnham 《Journal of the American Ceramic Society》1990,73(11):3339-3344
Screen-printed layers of Al2 O3 , BaTiO3 , 0.90Pb(Mg1/3 Nb2/3 )-03 –0.10PbTiO3 , Pb(Zr,Ti)O3 , ZnO, and glass alumina pastes have been patterned using photoprinting techniques. Curability of each paste by ultraviolet light and formation of holes with various diameters were studied for application as a production method for very small-sized vias. The dependence of hole diameters on various experimental parameters is presented and discussed. Wall slopes were found to depend on the transmission of the powders used in the pastes. 相似文献
96.
The effects of filler size on the properties of a thermoplastic polyolefin (TPO) blend were examined by using wollastonite and talc with particle sizes ranging from 1.2 to 40 μm. While addition of filler produced significant changes in the mechanical properties of the blend, filler size affected only impact strength. However, filler size, filler coating, and injection speed had a major effect on the surface properties of the blend. Faster injection produced denser “shear zone layers” which exhibited better scratch resistance and poorer paint adhesion than those obtained with slower injection. Scartch resistance and paint adhesion also decreased with increasing filler particle size. Filler coatings altered the scratch and adhesion properties of the polypropylene (PP) blends. 相似文献
97.
Carol Holland 《Accident; analysis and prevention》2010,42(4):1097-1106
Adult pedestrian accident data has demonstrated that the risk of being killed or seriously injured varies with age and gender. A range of factors affecting road crossing choices of 218 adults aged 17-90+ were examined in a simulation study using filmed real traffic. With increasing age, women were shown to make more unsafe crossing decisions, to leave small safety margins and to become poorer at estimating their walking speed. However, the age effects on all of these were ameliorated by driving experience. Men differed from women in that age was not a major factor in predicting unsafe crossing decisions. Rather, reduced mobility was the key factor, leading them to make more unsafe crossings and delay longer in leaving the kerb. For men, driving experience did not predict unsafe road crossing decisions. Although male drivers were more likely to look both ways before crossing than male non-drivers, the impact of being a driver had a negative effect in terms of smaller safety margins and delay in leaving the kerb. The implications of the different predictor variables for men and women for unsafe road crossing are discussed and possible reasons for the differences explored. 相似文献
98.
Following a midterm exam in an introductory psychology course, college students (N?=?189) were administered the same test items under nonevaluative conditions. The hypothesis that high-anxious individuals as compared with low-anxious individuals would retrieve a greater degree of information not previously available to them when they were assessed under reduced threat was only partially supported. However, easy-item performance provided some evidence for an interference phenomenon. An interaction indicated that previously blocked information became available only for those high-anxious students who had initially used effective study strategies. Path analysis confirmed the relative importance of anxiety phenomena to classroom test performance in a time-ordered causal network involving ability level, study effectiveness, and anxiety arousal. Results add credence to a recent interpretation of anxiety as a failure-of-self phenomenon. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
99.
Mitchell Karen J.; Johnson Marcia K.; Raye Carol L.; Mather Mara; D'Esposito Mark 《Canadian Metallurgical Quarterly》2000,15(3):527
It was hypothesized that age-related deficits in episodic memory for feature combinations (e.g., B. L. Chalfonte & M. K. Johnson, 1996) signal, in part, decrements in the efficacy of reflective component processes (e.g., M. K. Johnson, 1992) that support the short-term maintenance and manipulation of information during encoding (e.g., F. I. M. Craik, R. G. Morris, & M. L. Gick, 1990; T. A. Salthouse, 1990). Consistent with this, age-related binding deficits in a working memory task were found in 2 experiments. Evidence for an age-related test load deficit was also found: Older adults had greater difficulty than young adults when tested on 2 features rather than 1, even when binding was not required. Thus, disruption of source memory in older adults may involve deficits in both encoding processes (binding deficits) and monitoring processes (difficulty accessing multiple features, evaluating them, or both). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
Susanne I. Karsiotis Lindsey R. PierceJoshua E. Brown Carol A. Stepien 《Journal of Great Lakes research》2012
The Eurasian round goby (Neogobius melanostomus) invaded the freshwater North American Great Lakes in ~ 1990 via accidental introduction from ballast water discharge. Its genotypes in the Great Lakes traced to estuaries in the northern Black Sea, where the round goby flourishes in a variety of salinities to 22 parts per thousand (ppt). To prevent further introductions, U.S. and Canadian Coast Guard regulations now require that vessels exchange ballast water at sea before entering the Great Lakes. Since salinity tolerance of the invasive round goby population is poorly understood, we tested 230 laboratory-acclimated fish in three experimental scenarios: (1) rapid salinity increases (0–40 ppt), simulating ballast water exchange, (2) step-wise salinity increases, as during estuarine tidal fluxes or migration from fresh to saltwater, and (3) long-term survivorship and growth (to 4 months) at acclimated salinities. Almost all gobies survived experiments at 0–20 ppt, whereas none survived ≥ 30 ppt, and at 25 ppt only 15% withstood rapid changes and 30% survived step-wise increases. Ventilation frequencies were lowest at 10–15 ppt in step-wise experiments, in conditions that were near isotonic with fish internal plasma concentrations, reflecting lower energy expenditure for osmoregulation. Growth rates appeared greatest at 5–10 ppt, congruent with the larger sizes reached by gobies in Eurasian brackish waters. Thus, we predict that the Great Lakes round goby would thrive in brackish water estuaries along North American coasts, if introduced. However, oceanic salinities appear fatal to the invasive round goby, which likely cannot withstand complete seawater ballast exchanges or oceanic habitats. 相似文献