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231.
Eduardo Torres Dominguez Phong H. Nguyen Heather K. Hunt Azlin Mustapha 《Comprehensive Reviews in Food Science and Food Safety》2019,18(6):1825-1858
Food contact surfaces (FCS) in food processing facilities may become contaminated with a number of unwanted microorganisms, such as Listeria monocytogenes, Escherichia coli O157:H7, and Staphylococcus aureus. To reduce contamination and the spread of disease, these surfaces may be treated with sanitizers or have active antimicrobial components adhered to them. Although significant efforts have been devoted to the development of coatings that improve the antimicrobial effectiveness of FCS, other important coating considerations, such as hardness, adhesion to a substrate, and migration of the antimicrobial substance into the food matrix, have largely been disregarded to the detriment of their translation into practical application. To address this gap, this review examines the mechanical properties of antimicrobial coatings (AMC) applied to FCS and their interplay with their antimicrobial properties within the framework of relevant regulatory constraints that would apply if these were used in real‐world applications. This review also explores the various assessment techniques for examining these properties, the effects of the deposition methods on coating properties, and the potential applications of such coatings for FCS. Overall, this review attempts to provide a holistic perspective. Evaluation of the current literature urges a compromise between antimicrobial effectiveness and mechanical stability in order to adhere to various regulatory frameworks as the next step toward improving the industrial feasibility of AMC for FCS applications. 相似文献
232.
Suzanne N. Levine Andrea Lini Milton L. Ostrofsky Heather Burgess-Grant Andrea Lami Elizabeth Collyer-Gilles Daun Reuter Lindsay Schwarting-Miller Neil Kamman 《Journal of Great Lakes research》2018,44(5):1043-1056
Thirteen sediment cores from Lake Champlain (Vermont-New York- Quebec) were analyzed for sediment accumulation rate and eleven indicators of trophic status to reconstruct eutrophication history and relate it to phosphorus inputs from soil erosion, urban point sources, and agricultural runoff including P extracted from phosphate ore and brought to the catchment in fertilizer and livestock feed. Although the catchment was severely deforested and grazed by sheep and cattle in the 19th century, ten of thirteen sites accumulated excess sediment only in the 20th century, a consequence of slow sediment transport through the catchment. Of the three sites that received extra sediment, one remained oligotrophic, while two exhibited mild eutrophication. All sites underwent eutrophication in the 20th century. Three reached their current trophic status before agriculture's intensification, while point-source P input was maximal (1950–1980), four stayed in the reference state until agriculture intensified in the 1970s, and six responded incrementally first to point and then to agricultural P input. Pigment accumulation rates diminished at the surface of seven cores, evidence that the 1990s expansion of P removal from point sources reduced phytoplankton biomass. Additional water quality improvement depends on P management at the catchment border to balance inputs and outputs, and thus avoid P accumulation in soil that saturates phosphate sorption capacity, increasing the proportion of runoff P that is highly-bioavailable orthophosphate. Erosion control is of lower priority because the P native to the catchment's soil is of relatively low bioavailability, and retention structures do not retain dissolved P. 相似文献
233.
Jianwei Zhao Stephen D. Funni Emily R. Molina Elizabeth C. Dickey Jacob L. Jones 《Journal of the European Ceramic Society》2021,41(6):3357-3362
In situ high-energy X-ray diffraction (XRD) was performed on lead-zirconate-titanate-based ferroelectric materials with composition near the morphotropic phase boundary (MPB). The utilization of the two-dimensional area detector in in situ field-dependent experiments enables the complete analysis of the material response with respect to all azimuthal angles at each field amplitude. The studies reveal that the field-induced phase transition from tetragonal to rhombohedral is dependent on crystal orientation in Nb-doped PbZr0.53Ti0.47O3 that is in close compositional proximity to the MPB. However, only domain wall motion is activated in Nb-doped PbZr0.50Ti0.50O3, which is further in composition from the MPB. This synchrotron-based XRD characterization approach illustrates the importance in evaluating the orientation-dependence of phase transitions in piezoelectric and ferroelectric polycrystalline materials. 相似文献
234.
235.
Heather W. Neave Joao H.C. Costa J.B. Benetton Daniel M. Weary Marina A.G. von Keyserlingk 《Journal of dairy science》2019,102(11):10250-10265
Little is known about factors affecting individual variability in weaning age, feeding behavior, and growth of dairy calves. The objectives of this study were to (1) describe early-life individual characteristics of dairy calves and how these relate to weaning age, feeding behavior, and performance during the first 15 wk of age, and (2) to identify which of these individual characteristics predict weaning age of calves automatically weaned based on solid feed intake. Early-life characteristics of calves (n = 43) included scores for vitality at birth, drinking ability, learning ability to use the automated milk feeder in a group pen from d 1 of age, and personality traits assessed using exposure to a novel environment, a human, and an object at d 21 of age. Calves received 12 L/d of milk until d 30 when milk was reduced by 25% relative to the individual's previous 3-d intake average. Calves were weaned based on intake of solid feed (milk reduced by 25% at each of 2 intermediate solid feed intake targets, 225 and 675 g/d), and were weaned when they consumed 1,300 g/d of solid feed, resulting in variable weaning ages. A principal component analysis identified 5 factors that we labeled as low vitality, fearful, strong drinker, slow learner, and exploratory-active. Calves that were slow learners weaned at a later age, whereas fearful calves weaned earlier. No other early-life individual characteristics were associated with weaning age. Other characteristics (low vitality, strong drinkers, and exploratory-active) were associated with some measures of feeding behavior, feed intake, and growth, especially during the preweaning period. Measures of early solid feed intake (age to start eating and total preweaning intake) were best able to predict weaning age of calves. Individual early-life characteristics and measures of early solid feed intake can identify calves likely to do well or struggle during weaning. 相似文献
236.
We have examined the activity of three enzymes in pulmonary surfactant phosphatidylcholine synthesis following the hyperpnea
induced by having rats either inspire 5% CO2/13%O2/82% N2 for 24 hr or swim in thermoneutral water for 30 min. Both stimuli markedly increase frequency and tidal volume of breathing
and promote the release of surfactant. Lungs were perfused to remove blood, lavaged, and then homogenized in 1 mM Hepes, 0.15M
KCl at pH 7.0. The homogenate was centrifuged at 9,000 g (av) for 10 min to sediment the mitochondria and lamellar bodies
and at 100,000 g (av) for 60 min to obtain the microsomal and cytosol fractions. Incubations were carried out under determined
optimal conditions and zero order kinetics. Choline kinase (CK), cholinephosphate cytidylytransferase (CP-cyT) and choline
phosphotransferase (CPT) were assayed by the incorporation of [methyl-14C] choline chloride into phosphocholine, [methyl-14C]phosphocholine into CDPcholine, and [14C]CDPcholine into phosphatidylcholine, respectively. The incubation products were separated by thin-layer chromatography.
Whereas both forms of hyperpnea increased the activity of CP-cyT in the microsomal fraction, they had no effect on the activity
of either cytosolic CP-cyT and CK, or microsomal CPT. A similar increase in tidal volume in an isolated perfused rat lung
had no effect. We conclude that,in vivo, hyperpnea increases the activity of CP-cyT, the rate-limiting enzyme in phosphatidylcholine synthesis. Whether this is due
to an increase in the amount of enzyme, or of a cofactor, is unknown. 相似文献
237.
Heather Woll 《Information and Computation》1987,72(3)
Many number theoretic problems such as integer factorization and the discrete logarithm problem have defied all attempts to classify their complexities. Thirteen such problems are considered, none of which is known either to have a deterministic polynomial time solution, or to be complete for any natural complexity class. Failing this, the next best goal is to determine which among these are the “easiest” and which are the “hardest” problems. Toward this end, this paper gives an overview of reductions among the problems. Two reductions are new: a deterministic polynomial time reduction from squarefreeness to Euler's function φ(n), and a probabilistic polynomial time reduction from order modulo a prime power to discrete logarithm modulo a prime power. 相似文献
238.
Heather Boon Joyce Clitheroe Tonia Forte 《Revue canadienne de la pratique et de la recherche en diététique》2004,65(2):66-71
Greens+ is a popular natural health product marketed as energy-enhancing; however, no objective data substantiate this claim. The study objective was to determine if ingestion of greens+ 1. increases vitality, energy, and perception of well-being; 2. increases overall mental health and general health, and 3. decreases the incidence of colds and flus in an otherwise healthy female population. A total of 105 women were enrolled in this 12-week, randomized, double-blind, placebo-controlled clinical trial; 63 (60%) completed the treatment protocol. Both treatment and placebo groups showed a significant time trend effect, scoring better on all outcome measures as the trial progressed. Compared with the placebo group, the greens+ group scored marginally higher on vitality, the primary outcome measure (p=0.055), and significantly higher on energy (a secondary outcome measure, p=0.018). Findings were based on repeated measures analysis of variance; baseline scores were used as covariates. Although a trend toward greater improvement in the greens+ group was noted in the other secondary outcome measures, this trend did not reach statistical significance. Overall, our findings were positive but not conclusive that greens+ increases vitality and energy. These results provide justification for further study of the effects of greens+. 相似文献
239.
Heather E. Hudson 《Telematics and Informatics》1985,2(3):251-258
Progress has been slow in meeting rural communications needs. This article discusses the underlying problem of using demand to indicate need in rural areas. It also suggests other criteria which could be used, and points out policy pitfalls which may undermine rural services where they now exist. It suggests strategies for reversing current trends in countries without sufficient investment in rural telecommunications infrastructure, countries which have invested in satellite technology but have been reluctant to apply it to rural needs, and countries which now have rural services which may be jeopardized by changes in regulatory policy. 相似文献
240.