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101.
Helen Clare Lingard Keith Townsend Lisa Bradley Kerry Brown 《Construction Management & Economics》2013,31(10):1101-1112
Project‐based construction workers in the Australian construction industry work long and irregular hours and experience higher levels of work‐to‐family conflict and burnout than office‐based workers, giving rise to an interest in alternative work schedules as a means of supporting work–life balance. Alternative work schedules were implemented in four case study construction projects in Australia. Interventions differed between projects, with two implementing a compressed work week, and the others introducing reduced hours schedules (one of which was optional). Data were collected from each case study project, using various combinations of focus groups, surveys, interviews and daily diary collection methods. The results were mixed. The compressed work week appears to have been favourably received where it was introduced. However, waged workers still expressed concerns about the impact on their weekly ‘take‐home’ pay. Attempts to reduce work hours by changing from a six‐ to a five‐day schedule (without extending the length of the working day between Monday and Friday) were less favourably received. Waged workers, in particular, did not favour reduced hours schedules. The results confirm the existence of two distinct labour markets operating in the Australian construction industry and markedly different responses to alternative work schedules, based upon whether workers are waged or salaried. The results clearly show that attempts to improve work–life balance must take the structural characteristics of the industry's labour markets into consideration in the design of interventions. The impact of alternative work schedules is likely to be moderated by institutional working time regimes within the construction industry. 相似文献
102.
Paul Bowen Keith Cattell Peter J. Edwards Jonathan Marks 《Construction Management & Economics》2013,31(9):997-1006
The HIV/AIDS pandemic poses a substantial long‐term threat to economic development in South Africa. A questionnaire survey explored the perceptions of a sample of construction firms in the Western Cape regarding HIV/AIDS policy and treatment programmes. The findings show that there is no universal view about the long‐term threat of HIV/AIDS. Most organizations have awareness policies in place but prevention and treatment policies are less common. Treatment programmes are the least implemented of all intervention services due to insufficient resource capacity, the potential stigmatization of infected persons, and low take‐up rates. Despite an acknowledgement of the benefits flowing from mounting treatment programmes, doubt exists as to their financial viability. 相似文献
103.
Susan M. Bogus Keith R. Molenaar James E. Diekmann 《Construction Management & Economics》2013,31(8):829-837
Overlapping activities that are traditionally performed in a sequential manner can significantly reduce project delivery times. Overlapping, however, should be approached in a systematic manner to reduce the costs and risks. Information gathered from sector‐based case studies and from the manufacturing domain suggest a formalised framework for identifying overlapping opportunities and strategies can be successfully implemented for infrastructure projects. This framework considers activity characteristics, such as evolution of upstream information and sensitivity of downstream activities to changes in upstream information, to identify appropriate overlapping strategies. Overlapping strategies, such as early freezing of design criteria, overdesign, and early release of preliminary information, are selected based on activity characteristics. These strategies operate either by speeding up the evolution of upstream information or by reducing the sensitivity of downstream activities. By aligning overlapping strategies with activity characteristics, project managers can make better decisions on when and how much to overlap sequential activities to reduce overall project delivery time. 相似文献
104.
Effects of Recycling on the Mechanical Behavior of Polypropylene at Room Temperature Through Statistical Analysis Method 下载免费PDF全文
Fatemeh Khademi Yongsheng Ma Cagri Ayranci Keith Choi Kajsa Duke 《Polymer Engineering and Science》2016,56(11):1283-1290
This article reports the effects of recycled material percentage, annealing conditions, and glass fiber percentage on the mechanical behavior of injection molded polypropylene samples. Specimens were prepared with different percentages of recycled material ranging from 0 to 100%. Two groups of samples, i.e., non‐annealed and annealed at 150°C, were tested to investigate annealing effects. The effects of adding fiber (0–7.5%) to specimens was also investigated. It was found that increasing the amount of recycled material improves the material properties in a non‐linear trend. Annealing had a significant positive effect on both non‐fiber‐added and fiber‐added samples: it improved the yield stress of non‐reinforced polypropylene samples by more than 10% and their Young's modulus by about 50%. Fiber‐added materials showed more variability, and adding fiber also improved the Young's modulus and the yield stress of the samples by about 50%. The results indicate that the three factors investigated improved toughness of the injected polypropylene samples; however the effects are not significant. The study findings reveal that using recycled polypropylene has no significant effect on the material properties of polypropylene. POLYM. ENG. SCI., 56:1283–1290, 2016 © 2016 Society of Plastics Engineers 相似文献
105.
Yichi Zhang Julia Glaum Matthias C. Ehmke Keith J. Bowman John E. Blendell Mark J. Hoffman 《Journal of the American Ceramic Society》2016,99(4):1287-1293
(Ba,Ca)(Ti,Zr)O3 lead‐free piezoelectric ceramics have been considered to be one of the most potential lead‐free alternatives for PZT in the room‐temperature range. The stability of the piezoelectric performance during unipolar cycling is investigated in this study. It is found that the unipolar fatigue behavior is similar to soft PZT. Developments of bias field, offset polarization, asymmetry in strain, and dielectric hysteresis loops are observed during bipolar measurements. The changes are mainly contributed to the migration of charge carriers to the grain boundaries driven by the unscreened depolarization field. Redistribution of the accumulated charge carriers by bipolar electric cycling or thermal annealing can significantly recover the unipolar fatigued state. The unipolar strain response stabilized after 1000 cycles at 0.053% for an electric field of 0.6 kV/mm (d33*= 883 pm/V), which is a good characteristic for actuator applications. 相似文献
106.
107.
There is an increasing emphasis on using natural processes, including riparian forest restoration, to enhance the ecological, hydrological and geomorphological functioning of watercourses. However, we have insufficient knowledge on how the supply and retention of in‐channel wood from riparian forest stands changes with age, with inferences typically based on data from terrestrial forests. This presents a challenge in estimating the efficacy and functional lifespan of restoration projects. In this paper, we use a riparian forest growth model to show there is a lag of up to 40–50 years between the start of forest growth and trees delivering wood to the channel that is large enough to resist fluvial transport, anchor logjams and so increase channel complexity and hydraulic resistance. Resource managers need to account for realistic timescales over which changes promoted by riparian woodland restoration will occur and may need to consider using interim engineered logjams as the forest develops. 相似文献
108.
109.
Mladen Ladika Thomas H. Kalantar Hui Shao Stacey L. Dean J. Keith Harris Paul J. Sheskey Karen Coppens Karen M. Balwinski Debora L. Holbrook 《应用聚合物科学杂志》2014,131(7)
Polyampholyte latexes can exist within a certain pH range as low‐viscosity aqueous dispersions, while upon a pH shift to the vicinity of the isoelectric point they undergo ionic coacervation. Three classes of coacervation latexes were synthesized and evaluated for their suitability for use in tablet coating applications. Pharmaceutical tablet coatings are commonly based on hydroxypropyl methyl cellulose, poly(vinyl alcohol), and acrylic polymers. Because of the high viscosity of their aqueous solutions, and to the consequent required low concentrations of the tablet coating polymers in the coating solutions to enable sufficiently low viscosity for effective spray application, the current commercial pharmaceutical tablet coating technology requires the removal of large amounts of water during the manufacturing process. In this work, films prepared from high‐solids, low‐viscosity coacervated acrylic latexes showed good hardness, very low tackiness, an excellent combination of optical properties, and very low water vapor permeability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40049. 相似文献
110.
Myra K. Derbyshire Keith G. Weinstock Jeffrey N. Strathern 《Yeast (Chichester, England)》1996,12(7):631-640
A novel Saccharomyces cerevisiae gene, HST1, was identified from among anonymous cDNAs and the complete corresponding genomic clone was isolated and sequenced. HST1 is very closely related to SIR2, showing 71% sequence identity over 84% of its length. Polymerase chain reaction with degenerate primers on S. cerevisiae DNA identified three additional SIR2-related genes designated HST2, HST3 and HST4. The sequences of HST2, HST3 and HST4 correspond to sequences previously released by the S. cerevisiae genome sequencing project as U33335, NCBI gi:965078; X87331, NCBI gi:829135; and Z48784, YD9346.03, respectively. Disruption of HST1 has shown no phenotype with respect to mechanisms in which SIR2 has a role, namely, regional silencing of HMLα, or in rDNA recombination. The sequence of HST1 has been deposited in the DDBJ, EMBL and GenBank at NCBI database under Accession Number L47120. 相似文献