全文获取类型
收费全文 | 858篇 |
免费 | 27篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 34篇 |
综合类 | 2篇 |
化学工业 | 265篇 |
金属工艺 | 27篇 |
机械仪表 | 32篇 |
建筑科学 | 11篇 |
矿业工程 | 1篇 |
能源动力 | 27篇 |
轻工业 | 129篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 44篇 |
一般工业技术 | 128篇 |
冶金工业 | 113篇 |
原子能技术 | 14篇 |
自动化技术 | 56篇 |
出版年
2023年 | 11篇 |
2022年 | 24篇 |
2021年 | 25篇 |
2020年 | 19篇 |
2019年 | 15篇 |
2018年 | 18篇 |
2017年 | 17篇 |
2016年 | 17篇 |
2015年 | 25篇 |
2014年 | 27篇 |
2013年 | 57篇 |
2012年 | 41篇 |
2011年 | 45篇 |
2010年 | 25篇 |
2009年 | 33篇 |
2008年 | 41篇 |
2007年 | 35篇 |
2006年 | 38篇 |
2005年 | 20篇 |
2004年 | 18篇 |
2003年 | 26篇 |
2002年 | 23篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 17篇 |
1998年 | 40篇 |
1997年 | 35篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 12篇 |
1975年 | 3篇 |
1969年 | 1篇 |
排序方式: 共有886条查询结果,搜索用时 15 毫秒
91.
Toda Masanao; Shinotsuka Hiromi; McClintock Charles G.; Stech Frank J. 《Canadian Metallurgical Quarterly》1978,36(8):825
Observed the choice behavior of 868 dyads of 2nd-, 4th-, and 6th-grade children from 5 different cultural backgrounds (Mexican-American, Anglo-American, Japanese, Greek, and Belgian) in the maximizing difference game, an outcome interdependence task where individualistic and cooperative motives were placed in opposition to competitive ones. In 4 cultures, boys received either social comparison feedback or only information concerning their own cumulative scores. As predicted, the level of competitive responding increased as a function of age, social comparison information, and number of trials. Further, there were systematic cultural differences. A newly developed covariation analysis revealed that individual dyad variation accounted for more covariation than the main effects noted above. Hence, several types of within-dyad analyses were performed. Finally, cultures were classified in terms of the characteristic play by dyad members and the results compared with a classification developed by M. Mead (1937), in which she ordered the cooperative, competitive, and individualistic orientations of members of 13 "primitive" societies. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
92.
Various kinds of mercaptoethylated graft fibers were prepared and the abilities to adsorb the heavy metal ions were studied. 2-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and vinyl acetate were graft-copolymerized by irradiation onto five kinds of synthetic fibers and two kinds of foam polymers. Preirradiation at low temperature was far more effective for grafting than simultaneous irradiation. The mercaptoethylation was carried out in the solution or in the vapor of ethylene sulfide onto the graft fibers treated with alkali. The mercaptoethylated graft fibers showed particular affinity for Hg and Ag ions. A few of the adsorption phenomena were pursued by flow experiment of the ionic solution through a column. The preliminary reduction of the mercaptoethylated graft fibers enhanced the capacity of adsorbing to three times that of the unreduced fibers. Effects of flow rate, pH, temperature, and concentration of Hg ion on the integrated adsorbed amount were also investigated. 相似文献
93.
A ceramics acid, calcined at temperatures above 1000 °C, was obtained by impregnating aluminum hydroxide with aqueous ammonium
metatungstate followed by calcining in air at 1000–1200 °C (1–5 wt% W); its acidity and catalytic activity for decompositions
of toluene, ethylbenzene, and cumene are higher than those of silica-alumina. 相似文献
94.
K Yamane T Shima Y Okada M Nishida S Okita T Hatayama T Nishida 《Canadian Metallurgical Quarterly》1994,42(5):433-437
A rare case of primary pineal melanoma is reported. The patient was a 53-year-old woman who complained of a severe headache. Computed tomography and magnetic resonance images revealed obstructive hydrocephalus caused by a mass lesion in the pineal region. A biopsy was performed through an occipital transtentorial approach. A black pigmented solitary tumor was seen without leptomeningeal dissemination. Histologic examination revealed melanoma. Chemotherapy consisting of dacarbazine, ACNU, vincristine, and interferon was used. Follow-up imaging studies showed dramatic reduction of the tumor without recurrence for 4 years. This report demonstrates that a solitary primary intracranial melanoma without leptomeningeal dissemination and with rare mitoses may yield a good result with chemotherapy. 相似文献
95.
The action of Taka-amylase A from Asp. oryzae was studied quantitatively by the product analysis method using unlabeled maltotriose and maltotriose labeled at the reducing end as substrates. It was found that the ratio of the unlabeled products, maltose (G2) and glucose (G1) exceeded unity, and that the ratio of the labeled products, G2/G1 was strongly dependent on the initial substrate concentrations. The results can only be explained by a transglycosylation or condensation mechanism or both. Analysis of maltose labeled at the nonreducing or reducing end reveal that the ratio of the transglycosylation to the condensation mechanism was about 20:1 with about 80 mM maltotriose. A computer simulation was made on a reaction scheme involving the termolecular-shifted complex, transglycosylation and condensation besides hydrolysis, by using reported subsite affinities as modified by the authors. The simulation reproduced the experimental results satisfactorily. 相似文献
96.
Shozo Ishizaka John G. Stockner Katsumi Kobayashi Kunihiro Shima Kenji Katori Humitake Seki 《Water research》1983,17(12):1815-1821
Multi-elemental traces comprising particulate matter in natural water collected during summer in 1978 and 1979 from British Columbia, Canada, were analyzed by α-particle excited X-ray fluorometry. Common elements from all waters examined were Si, Cl, Ca and Fe. The similarity of their distribution in different aquatic environments was statistically analyzed. They were distributed homogeneously in the marine environment but heterogeneously in the freshwater environments. No heavy metals concerned with the environmental standards were detected for all waters examined. 相似文献
97.
Shima Ghaffari Maryam Yousefzadeh Fatemeh Mousazadegan 《Polymer Engineering and Science》2019,59(10):2032-2040
The development of functional nanofiber materials with high specific surface area and porosity has been a highly interesting field of research in recent years due to its versatile properties for diverse applications. The combination of nanofibers into material clothes can open up new opportunities to improve comfort performance and thermal management properties. In this work, we demonstrated that the porous lightweight nanofibrous membrane could be coated on the fabric and laminated to improve its thermal comfort. The polyacrylonitrile was electrospun onto the surface of the polyester fabric with three different fineness and laminated with a warp knitted interlining in a controlled condition by sewing/fusing. The effect of the nanofibers diameter, sewing and fusing process on thermal insulation, air permeability, breathability, and water resistance of the obtained three‐layer samples were studied. The results showed that the presence of the nanofibers thin layer could improve the thermal comfort by controlling the studied parameters compared to the external face fabric as control. It was obtained that the fusing technique is more efficient than sewing for this purpose. The fused samples are waterproof and windproof, while instantly venting moisture and had good thermal insulation to protect the body from cold. POLYM. ENG. SCI., 59:2032–2040, 2019. © 2019 Society of Plastics Engineers 相似文献
98.
Hirano S Shima T Shimada T 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2001,42(4):237-242
Moldy and split peanut kernels were separated from peanuts exported from Brazil, Sudan, India and Taiwan by visual inspection. The remaining peanuts from Brazil, Sudan and India were roasted lightly and the skins were removed. Stained peanuts were separated from the others. Aflatoxin was detected in moldy and stained peanuts. There was a positive correlation between % of aflatoxin-contaminated peanut kernels and aflatoxin B1 concentration in whole samples. Aflatoxin concentration of moldy peanuts was higher than that of stained peanut kernels. 相似文献
99.
100.
Akiba T Tanaka T Nagano M Mori K Hayashi Y Obata H Chiba T Ikuta Y Kamiya Y Nakama A Hosaka M Kai A 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2010,51(5):237-241
Norovirus (NV) RNA has rarely been detected in foods despite the use of highly sensitive methods such as RT-PCR and real-time RT-PCR. In the modified method (A3T method) reported previously, a bacterial culture process was introduced into the standard protocol for NV detection to remove some inhibitor(s) present in food ingredients. To confirm the efficiency of the A3T method and to examine NV contamination in bivalve molluscs, we tried to detect NV RNA in bivalve molluscs on the market and in oyster samples associated with foodborne outbreaks by using the standard method and the A3T method. NV RNAs were detected in 20 samples (18.0%) of 111 bivalve molluscs, including oysters, on the market by use of the A3T method, while only one sample (0.9%) was positive according to the standard method. NV RNA was also detected in 10 of 35 oyster samples related to foodborne outbreaks by the A3T method. Those results show that the A3T method is suitable for the detection of NV in bivalve molluscs in general laboratories. 相似文献