全文获取类型
收费全文 | 805篇 |
免费 | 22篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 121篇 |
金属工艺 | 4篇 |
机械仪表 | 12篇 |
建筑科学 | 25篇 |
矿业工程 | 5篇 |
能源动力 | 17篇 |
轻工业 | 109篇 |
水利工程 | 4篇 |
无线电 | 40篇 |
一般工业技术 | 120篇 |
冶金工业 | 279篇 |
原子能技术 | 9篇 |
自动化技术 | 80篇 |
出版年
2022年 | 11篇 |
2021年 | 13篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 11篇 |
2016年 | 5篇 |
2015年 | 10篇 |
2014年 | 17篇 |
2013年 | 37篇 |
2012年 | 28篇 |
2011年 | 44篇 |
2010年 | 26篇 |
2009年 | 28篇 |
2008年 | 20篇 |
2007年 | 33篇 |
2006年 | 32篇 |
2005年 | 22篇 |
2004年 | 20篇 |
2003年 | 18篇 |
2002年 | 17篇 |
2001年 | 15篇 |
2000年 | 17篇 |
1999年 | 21篇 |
1998年 | 39篇 |
1997年 | 30篇 |
1996年 | 26篇 |
1995年 | 19篇 |
1994年 | 9篇 |
1993年 | 14篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 15篇 |
1988年 | 19篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 14篇 |
1982年 | 5篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1972年 | 6篇 |
1971年 | 4篇 |
排序方式: 共有828条查询结果,搜索用时 15 毫秒
11.
Paul R. Chalker Paul A. Marshall Richard J. Potter Timothy B. Joyce Anthony C. Jones Stephen Taylor Timothy C. Q. Noakes P. Bailey 《Journal of Materials Science: Materials in Electronics》2004,15(11):711-714
The hafnium and silicon precursors, Hf(NMe2)4 and ButMe2SiOH, have been investigated for the MOCVD of high-κ hafnium silicate, (HfO2)1–x –(SiO2) x films for gate dielectric applications. Control of the silica concentration in the hafnium silicate can be achieved by varying the relative precursor ratios up to a saturation level of 35–40% SiO2. The thermal stability of the resulting hafnium silicate films in air has been investigated using medium energy ion scattering. Internal oxidation of the underlying silicon substrate is discernable when the films are annealed in dry air for 15 min over the temperature range 800–1000 °C. 相似文献
12.
Gerson Reginaldo Marques Soraia Vilela Borges Diego Alvarenga Botrel Joyce Maria Gomes da Costa Eric Keven Silva Jefferson Luiz Gomes Corrêa 《Drying Technology》2014,32(7):861-868
Maize (Zea mays) is a cereal grown in Brazil, and its availability is limited to the harvest season. An alternative processing route is based on the production of green corn powder, which has a longer shelf-life and increased versatility. This study aimed to evaluate the influence of drying conditions on the physical characteristics, size, and morphology of green corn powder. Drying experiments were performed on a spray dryer according to a central composite rotational design to evaluate inlet air temperature, feed flow rate, and pulp concentration. The yield of dried pulp corn had an average value of 36.19%. The following mean values for the physical properties of the powder were measured: solubility of 94.37 g/100 g, wettability of 128.05 seconds, moisture content of 1.97%, water activity of 0.13, density of 0.79 g/mL, and a particle diameter of 31.02 µm. The powder was also yellow with less intensity, and the particle surface was smooth at higher temperatures and had a tendency to form agglomerates. The estimated optimal conditions for spray drying were 48% (w/w) pulp concentration, 172°C inlet air temperature, and feed flow rate of 0.56 L/h. 相似文献
13.
Gary J. Blomquist Charles L. Soliday Barbara A. Byers Joyce W. Brakke Larry L. Jackson 《Lipids》1972,7(5):356-362
Wax esters of secondary alcohols constitute 18–20% of the cuticular lipid extract ofMelanoplus packardii and 26–31% of the cuticular lipids ofMelanoplus sanguinipes. The total number of carbons in the wax esters range from 37–54 with 41 predominating in both species. The fatty acids ofM. packardii wax esters are 16∶0, 18∶0, 14∶0, 20∶0 and 12∶0 in decreasing quantity. The fatty acids ofM. sanguinipes wax esters are 18∶0, 20∶0, 16∶0 22∶0, 14∶0, 19∶0 and 17∶0 in decreasing quantity. The secondary alcohols from the wax esters
ofM. packardii are C25, C23 and C27 in decreasing quantity, and the secondary alcohols of theM. sanguinipes are C23, C25, C21, C27, C24, C22 and C26 in decreasing quantity. Each secondary alcohol consists of two to four isomers with the hydroxyl group located near the center
of the chain.
Montana Agriculture Experiment Station, Journal Series No. 332. 相似文献
14.
15.
16.
Washington Lindsay A.; Wilson Sylia; Engel Joyce M.; Jensen Mark P. 《Canadian Metallurgical Quarterly》2007,52(2):241
Objective: To develop and evaluate a new pediatric measure of community integration: the Pediatric Community Participation Questionnaire (PCPQ). Participants: 105 youths with physical disabilities. Measures: In addition to the PCPQ, demographic and disability-related questions and the Functional Disability Inventory (FDI) were administered. Results: The PCPQ demonstrated convergent validity through its high association with functional ability, discriminant validity through its ability to discriminate between ambulatory and nonambulatory participants, and excellent internal consistency. Conclusions: Community participation, an important component of positive overall development, may be particularly important for youths with physical disabilities. The findings from this study provide preliminary support for the validity and reliability of the PCPQ, supporting its use as a measure of community participation with this population. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
17.
Vitaliano Peter P.; Echeverria Diana; Yi Joyce; Phillips Paul E. M.; Young Heather; Siegler Ilene C. 《Canadian Metallurgical Quarterly》2005,20(3):402
The authors examined relationships between chronic stress and cognitive decline and whether such relationships were mediated by psychophysiological factors. Ninety-six caregivers of spouses with Alzheimer's disease (AD) were compared with 95 similar noncaregiver spouses. All were free of diabetes. Although the groups started similarly, over 2 years caregivers declined by a small but significant amount (1 raw score point and 4 percentile points, each p 相似文献
18.
Dr. Christopher L. Schardon Dr. Alfred Tuley Dr. Joyce A. V. Er Jake C. Swartzel Dr. Walter Fast 《Chembiochem : a European journal of chemical biology》2017,18(15):1551-1556
We have investigated 4‐halopyridines as selective, tunable, and switchable covalent protein modifiers for use in the development of chemical probes. Nonenzymatic reactivity of 4‐chloropyridine with amino acids and thiols was ranked with respect to common covalent protein‐modifying reagents and found to have reactivity similar to that of acrylamide, but could be switched to a reactivity similar to that of iodoacetamide upon stabilization of the positively charged pyridinium. Diverse, fragment‐sized 4‐halopyridines inactivated human dimethylarginine dimethylaminohydrolase‐1 (DDAH1) through covalent modification of the active site cysteine, acting as quiescent affinity labels that required off‐pathway catalysis through stabilization of the protonated pyridinium by a neighboring aspartate residue. A series of 2‐fluoromethyl‐substituted 4‐chloropyridines demonstrated that the pKa and kinact/KI values could be predictably varied over several orders of magnitude. Covalent labeling of proteins in an Escherichia coli lysate was shown to require folded proteins, indicating that alternative proteins can be targeted, and modification is likely to be catalysisdependent. 4‐Halopyridines, and quiescent affinity labels in general, represent an attractive strategy to develop reagents with switchable electrophilicity as selective covalent protein modifiers. 相似文献
19.
20.
Piper William E.; Ogrodniczuk John S.; Joyce Anthony S.; Weideman Rene 《Canadian Metallurgical Quarterly》2009,13(1):46
This study investigated 4 types of outcome over a 6-month follow-up period for 84 psychiatric outpatients who had been treated for complicated grief using short-term group therapy. The 4 types differed in regard to whether and when patients achieved clinically significant change on a primary grief outcome variable. Approximately half of the patients achieved clinically significant change by the end of treatment and maintained it over follow-up (maintenance). Another quarter of the patients reported clinically significant change, but only at follow-up (delayed recovery). A few patients achieved clinically significant change at the end of treatment, but not at follow-up (relapse). Finally, nearly a quarter of the patients failed to achieve clinically significant change (nonrecovery). The findings suggest that investigators look beyond the end of treatment when assessing improvement in patients treated with short-term group therapy for complicated grief. Inclusion of delayed recovery patients can substantially modify conclusions about the usefulness of short-term therapies for complicated grief. Delayed recovery patients differed from the other types of patients on greater perceived social support and greater change during the follow-up period. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献