全文获取类型
收费全文 | 1494篇 |
免费 | 38篇 |
国内免费 | 7篇 |
学科分类
工业技术 | 1539篇 |
出版年
2024年 | 4篇 |
2023年 | 22篇 |
2022年 | 33篇 |
2021年 | 53篇 |
2020年 | 33篇 |
2019年 | 36篇 |
2018年 | 47篇 |
2017年 | 37篇 |
2016年 | 47篇 |
2015年 | 19篇 |
2014年 | 61篇 |
2013年 | 77篇 |
2012年 | 70篇 |
2011年 | 73篇 |
2010年 | 67篇 |
2009年 | 71篇 |
2008年 | 58篇 |
2007年 | 59篇 |
2006年 | 36篇 |
2005年 | 37篇 |
2004年 | 35篇 |
2003年 | 41篇 |
2002年 | 32篇 |
2001年 | 31篇 |
2000年 | 23篇 |
1999年 | 15篇 |
1998年 | 37篇 |
1997年 | 23篇 |
1996年 | 20篇 |
1995年 | 30篇 |
1994年 | 20篇 |
1993年 | 19篇 |
1992年 | 26篇 |
1991年 | 27篇 |
1990年 | 21篇 |
1989年 | 26篇 |
1988年 | 12篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 25篇 |
1984年 | 24篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 12篇 |
1973年 | 7篇 |
排序方式: 共有1539条查询结果,搜索用时 15 毫秒
101.
Kankana Baruah Riku Dutta Simanta Doley Bipul Sarma Swapan Kumar Dolui 《应用聚合物科学杂志》2024,141(2):e54767
Excess metal pollutant has affected and caused serious havoc in the lives of terrestrial as well as aquatic beings. The core of this work revolves around eradicating highly toxic heavy metal ions from underground water systems using a cost-effective, high removal efficiency polymeric adsorbent capable of adsorbing and removing ionic metals whose backbone is composed of a bio-degradable polymer, polyvinyl alcohol. The obtained adsorbent was characterized using FT-IR, HNMR, and P-XRD. Morphological studies were carried out using SEM. Detection and adsorption of metal ions were performed using SEM–EDX and AAS; wherein the adsorbent was found to remove nearly 80% of arsenic ions, 70.5% and 70.7% for lead and chromium ions while 60.7% for cadmium ions, respectively. Further, the kinetics of adsorption along with intraparticle diffusion studies were also performed to determine the mechanism alongside observing the isothermal influence of the sorbent. The adsorption capacity was seen to be highest in arsenic at around 570.42 mg g−1 thus acting as a potential and effective adsorbent for the removal of heavy metal ions from groundwater. 相似文献
102.
Debarun Dutta Timothy Zhao Kai Bing Cheah Larke Holmlund Mark D.P. Willcox 《Contact lens & anterior eye》2017,40(3):175-183
Purpose
To determine the antimicrobial activity of the melimine derived peptide Mel4 against Delftia, Stenotrophomonas, Elizabethkingia, Burkholderia and to investigate biocompatibility of Mel4 as an antimicrobial coating on contact lenses in animals and humans.Methods
In vitro antimicrobial activity of Mel4 was determined against the four Gram negative bacteria by investigating growth curves for 24 h followed by viable counts to determine the minimum inhibitory concentration (MIC). Contact lenses were coated by covalently binding Mel4, characterized by amino acid analysis, and were investigated for changes in lens parameters. Safety of Mel-4 coated lenses were determined in a rabbit model of daily contralateral wear. A prospective, randomised, double-masked, contralateral, 1week daily wear human clinical trial was used to evaluate subjective responses and ocular physiology.Results
Mel4 was active against all the bacteria tested (MIC50 ranged from 31–1000 μg ml?1) and produced an antimicrobial surface on contact lenses. Mel4-coating resulted hydrophilic surface without any significant change in contact lens parameters, and showed no signs of cytotoxicity or ocular irritation during rabbit wear. During human clinical trial, there were no differences between Mel4 coated and uncoated contact lenses in lens performance indicators and ocular signs such as corneal fluorescein staining. Mel4 and control uncoated lenses had no differences in ocular symptoms during lens wear.Conclusion
Mel4 has achieved antimicrobial activity against variety of Gram negative bacteria that are often resistant to the action of cationic peptides and have been implicated in contact lens related adverse events. Mel4-coated contact lenses were safe to wear. 相似文献103.
Lopamudra Sahu Awanish Kumar Mishra Krishna Dutta 《Journal of Materials Engineering and Performance》2014,23(11):4122-4129
Ratcheting fatigue behavior of a non-conventional stainless steel X12CrMnNiN17-7-5 has been investigated with varying combinations of mean stress (σm) and stress amplitude (σa) at room temperature using a servo-hydraulic universal testing machine. X-ray diffraction profile analysis has been carried out for assessing possible martensitic phase transformation in the steel subjected to ratcheting deformation. The results indicate that ratcheting strain as well as volume fraction of martensite increases with increasing σm and/or σa; the phenomenon of strain accumulation is considered to be governed by the associated mechanics of cyclic loading, increased plastic damage as well as martensitic transformation. A correlation between strain produced by ratcheting deformation and martensitic transformation has been established. 相似文献
104.
Debabrata Pradhan Akshya Kumar Guin Pankaj Raju Manindra Manna Monojit Dutta T. Venugopalan 《Journal of Materials Engineering and Performance》2014,23(9):3336-3346
Galvannealed steel sheets (GA) have become the mainstream steel sheet for automobile applications because of their superior corrosion resistance, paintability, and weldability. To impart specific properties, different coatings on GA steel sheet were reported to improve properties further. In this context, we have developed an electroplating process (flash coating) for bright and adherent Fe-Zn alloy coating on GA steel sheet to enhance performances such as weldability, frictional behavior, phosphatability, and defect coverage. A comparative study with bare GA steel sheet was carried out for better elastration. The electroplating time was reduced below 10 s for practical applicability in an industrial coating line by modulating the bath composition. Electroplating was performed at current density of 200-500 A/m2 which yielded with higher cathode current efficiency of 85-95%. The performance results show that Fe-10 wt.% Zn-coated GA steel sheet (coating time 7 s) has better spot weldability, lower dynamic coefficient of friction (0.06-0.07 in lubrication), and better corrosion resistance compared to bare GA steel sheet. Uniform phosphate coating with globular crystal size of 2-5 µm was obtained on Fe-Zn flash-coated GA steel sheet. Hopeite was the main phosphate compound (77.9 wt.%) identified along with spencerite (13.6 wt.%) and phosphophyllite (8.5 wt.%). 相似文献
105.
H. Gao R. K. Dutta R. M. Huizenga M. Amirthalingam M. J. M. Hermans T. Buslaps 《Science & Technology of Welding & Joining》2014,19(3):256-264
In multipass welding, each successive thermal cycle will introduce local melting, solid state phase transformations, grain growth, grain refinement, recrystallisation and recovery, all of which lead to a complicated stress state. Most stress measurements performed on multipass welded components represent the final residual stress state. Information concerning stress evolution on a pass-by-pass basis is difficult to find. In this investigation, six pass welds were made on high strength quenched and tempered steel sections, and depth resolved strain measurements in two orthogonal directions were carried out after each weld pass using energy dispersive synchrotron X-ray diffraction. The residual stresses were calculated using biaxial Hooke’s law. A thermal–metallurgical–mechanical welding model was constructed and validated with temperature and pass-by-pass stress measurements, which improves the reliability of the model. Cross-sectional stress distributions are presented after each pass, revealing the weld stress development in multipass welds. 相似文献
106.
107.
Manisha Choudhury Lipi B. Mahanta Jayashree Sarmah Goswami Meenakshi Dutta Mazumder 《Food Control》2011,22(8):1233-1239
Successful food hygiene training and the consent of safe food handling practices learnt during training are critical elements in the control of food-borne illnesses throughout the world. It is true for food handlers and vendors belonging to all sectors. But, it is all the more urgent for street vendors because they are more exposed to environmental hazards and are predominantly from much weaker socio-economic backgrounds and yet cater to the general mass. Using a cross-sectional study design a sample of 80 street food vendors were selected and provided with training to evaluate the existing Knowledge, Attitude and Practice (KAP) regarding food safety and hygiene and the change of the same after training interventions. Responses regarding KAP on food safety and hygiene before and after training revealed that there was a significant change in their perception to food safety knowledge and also practices. The knowledge level of the food vendors increased from an average 24.35%–66.2% after training interventions. The overall performance rating of full adoption of good hygiene practices by the vendors ranged from 37.5% to 50.8% in post-training period. 相似文献
108.
109.
Pushkar N. Patil Sudarshan Kathi Dhanadeep Dutta Pradeep K. Pujari 《Polymer Bulletin》2010,65(6):577-587
Poly (N-isopropyl acrylamide) gels were prepared by UV polymerization with different degree of cross-linking in different solvents.
Ethylene glycol dimethacrylate and penta-erythritol tetra-acrylate were used as cross-linkers, and methanol and dimethyl formamide
(DMF) were used as solvents for gel preparation. The free volume fraction and hole size distribution in the dry gels were
measured using positron annihilation lifetime spectroscopy. The equilibrium swelling of the samples in water was measured
at room temperature. Both swelling properties of gels and the free volume distributions were seen to be sensitive to the amount,
type, and functionality of cross-linkers as well as solvent medium used for synthesis. The gels prepared in DMF showed poor
swelling properties than those prepared in methanol. The mean free volume hole size was higher while the variance of hole
size distribution was smaller in the gels prepared in DMF medium compared to those prepared in methanol. The free volume fractions
in the gels were found to be inversely correlated to the extent of equilibrium swelling for similar chemical compositions.
The possible reasons are discussed. 相似文献
110.
The technique of electrospinning offers the advantage of growing nanowires in bulk quantities in comparison with traditional
methods. We report optical studies of polycrystalline zinc oxide (ZnO) nanofibers (∼100 nm thick and 5 μm long) deposited by electrospinning. Photoluminescence from the nanofibers shows a near-ultraviolet (near-UV) peak corresponding
to near-band-edge emission and a strong broad peak in the visible region from oxygen antisite and interstitial defects. Temperature-dependent
photoluminescence spectroscopy reveals that different carrier recombination mechanisms are dominant at low temperature. Our
Raman spectroscopy results demonstrate that characterization of the quasimodes of longitudinal optical (LO) and transverse
optical (TO) phonons present in an ensemble of polycrystalline nanofibers tilted at various angles in addition to the dominant
E
2(high) mode provides a promising technique for assessing the quality of such randomly oriented nanowires. 相似文献