全文获取类型
收费全文 | 205篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 40篇 |
金属工艺 | 8篇 |
机械仪表 | 5篇 |
建筑科学 | 11篇 |
矿业工程 | 1篇 |
能源动力 | 9篇 |
轻工业 | 16篇 |
水利工程 | 2篇 |
无线电 | 28篇 |
一般工业技术 | 70篇 |
冶金工业 | 13篇 |
原子能技术 | 3篇 |
自动化技术 | 13篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 9篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 9篇 |
2012年 | 11篇 |
2011年 | 11篇 |
2010年 | 13篇 |
2009年 | 12篇 |
2008年 | 12篇 |
2007年 | 17篇 |
2006年 | 16篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 8篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1957年 | 3篇 |
排序方式: 共有221条查询结果,搜索用时 21 毫秒
91.
Olle Anderbrant Marie Bengtsson Jan Löfqvist Peter Baeckström 《Journal of chemical ecology》1992,18(10):1707-1725
Two dispenser types for pine sawfly (Hymenoptera: Diprionidae) pheromones—glass capillaries and dental cotton rolls—are described,
and release rates reported. Glass capillaries of different diameters were used in field tests to determine dose-response relationships
of (2S,3S,7S)-3,7-dimethylpentadecan-2-yl acetate (diprionyl acetate), diprionyl propionate, andtrans-perillenal on the trap catch of maleNeodiprion sertifer. A linear relationship between the logarithm of the capillary cross-sectional area and the logarithm of the release rate
was found. However, capillaries of the same diameter could vary in the amount released by as much as a factor of 10. Both
the acetate and propionate were attractive alone, but no synergistic effect was found.trans-Perillenal did not show any behavioral activity. Dental cotton rolls have been used extensively in diprionid pheromone research
without knowledge about release rates. The release rate from rolls loaded with different amounts of diprionyl acetate was
determined by extracting rolls after different times under constant temperature and wind conditions or after use in field
tests. Quantification of diprionyl acetate was done on GC. The release rate was found to be proportional to the amount applied
over several orders of magnitude, and persisted for several weeks. Capillaries and rolls with similar release rates caught
similar numbers of sawflies. 相似文献
92.
Olsson PO Anderbrant O Löfstedt C Borg-Karlson AK Liblikas I 《Journal of chemical ecology》2005,31(12):2947-2961
Volatiles from chocolate mediate upwind flight behavior in Ephestia cautella and Plodia interpunctella. We used gas chromatography with electroantennographic detection and found 12 active compounds derived from three different
chocolate types, i.e., plain, nut-containing, and rum-flavored. Eight of the compounds were identified with mass spectrometry,
and the activity of three compounds, ethyl vanillin, nonanal, and phenylacetaldehyde (PAA), was subsequently confirmed in
both electrophysiological and behavioral assays. In the electroantennogram experiment, PAA and nonanal were consistently eliciting
responses in both species and sexes. Ethyl vanillin was active in males of both species, and also in P. interpunctella females. E. cautella females showed no antennal activity in response to ethyl vanillin. All three volatiles were attractive to E. cautella males and P. interpunctella females in a flight tunnel. E. cautella females were significantly attracted only to ethyl vanillin. P. interpunctella males were attracted to PAA. Ethyl vanillin is a novel insect attractant, whereas both nonanal and phenylacetaldehyde mediate
behavior in many insect species. A final experiment revealed that a blend of the three volatiles was required to induce landing
in the flight tunnel bioassay, and that the landing rate was dependent on dose. The three-component blend attracted both sexes
of P. interpunctella and females of E. cautella, whereas E. cautella males were not attracted. 相似文献
93.
Olle Viotti Andreas Fischer Gulaim A. Seisenbaeva Vadim G. Kessler 《Inorganic chemistry communications》2010,13(6):774-777
The first representatives of alkoxy-zircono-silsesquioxane compounds, dinuclear [Cy7Si7O12]Zr(ROH)(μ-OR)2Zr(ROH)[O12Si7Cy7], where R = nPr, nBu, tBu; Cy = c-C6H11, and [Cy*7Si7O12]Zr(μ-ROH)(μ-OR)2Zr[O12Si7Cy*7], R = tBu; Cy* = c-C5H9, have been prepared with quantitative yield by interaction of the corresponding zirconium alkoxides with the cycloalkyl-substituted cage silsesquioxanes in hexane. The X-ray single crystal study of the n-butoxide derivative revealed that zirconium atoms are hexacoordinated with the 3 oxygen atoms of the cage ligand, 2 — from the bridging alkoxide groups and one — from the solvating alcohol molecule in the coordination sphere. The molecule is additionally supported by a hydrogen bond between the solvating alcohol and an oxygen atom belonging to the cage ligand coordinated by the other zirconium atom. The structures of produced silsesquioxanes display behavior typical for metal–organic frameworks as they crystallize initially as hexane clathrates, but lose the solvent on storage in inert atmosphere. This results in formation of empty channels situated along the c-axis. 相似文献
94.
95.
Antti A Mero Heikki Huovinen Olle Matintupa Juha J Hulmi Risto Puurtinen Hannele Hohtari Tuomo AM Karila 《Journal of the International Society of Sports Nutrition》2010,7(1):1-11
Background
Intense exercise induces increased blood neutrophil counts and decreased lymphocyte counts, and leads to inflammation and immunosuppression. It was previously reported that cystine and theanine (CT) supplementation by long-distance runners before a training camp suppressed the changes of these blood parameters observed in un-supplemented control subjects after the camp. The purpose of the present study was to determine the effects of CT supplementation on the inflammatory response and immune state before and after intense endurance exercise in long-distance runners at a training camp.Methods
Sixteen long-distance runners were allocated to one of two groups given CT supplements (700 mg cystine + 280 mg theanine daily) or placebo (8 in each group) for 7 days prior to and during a 9-day training camp. Daily run training averaged 19.9 km/day prior to the camp and 28.6 km/day during the camp. On the initial and final days of the camp, blood samples were collected before and after 15 km morning interval running workouts (1000 m × 15 times) and analyzed for neutrophil and lymphocyte counts and myoglobin.Results
The relative change in exercise-induced blood neutrophil count (% of pre-exercise values) was significantly lower in the CT group than in the placebo group (163.3 ± 43.2% vs. 200.4 ± 19.6%, p = 0.044) on the initial day of camp, but not on the last day. The decline in lymphocyte count (% of pre-exercise values) was significantly less in the CT group than in the placebo group (60.2 ± 19.2% vs. 36.2 ± 12.0%, p = 0.010) on the initial day of camp, but not on the last day. In blood myoglobin, there was a trend toward lower % of pre-exercise values in the CT group (p < 0.09) on both measurement days.Conclusion
CT supplementation significantly attenuated the increase in neutrophil count and the reduction in lymphocyte count induced by intense endurance exercise. These results suggest that CT supplementation may suppress the exercise-induced fluctuation of the blood immunocompetent cells and may help to reduce the alteration of the immune state. 相似文献96.
97.
Hong-Lei Wang Glenn P. Svensson Olle Rosenberg Marie Bengtsson Erling V. Jirle Christer Löfstedt 《Journal of chemical ecology》2010,36(3):305-313
The spruce seed moth, Cydia strobilella L., is a serious pest on cones of spruce (Picea spp.) in the Holarctic region. Previous studies from different parts of its area of distribution have reported conflicting results on the composition of its sex pheromone. By gas chromatography with electroantennographic detection, coupled gas chromatography-mass spectrometry, a Y-tube olfactometer bioassay, and field trials, the sex pheromone of Swedish populations of the species was identified as (8E,10E)-dodecadienyl acetate and (8E,10Z)-dodecadienyl acetate. About 0.5 pg of each pheromone component was extracted per female. The most attractive blend of EE- and EZ-isomers was about 6:4, respectively, and 0.3 μg of the blend per rubber septum was the most attractive dosage for field trapping. Monounsaturated components previously reported as sex pheromone components/attractants for C. strobilella, (E)-8-dodecenyl acetate in Canadian populations and (Z)-8-dodecenol in Polish and Dutch populations, did not attract any C. strobilella in this study. Large numbers of C. jungiella Clerck were trapped by using (8E,10Z)-dodecadienyl acetate alone, whereas (Z)-8-dodecenol attracted Pammene splendidulana Guenée and P. rhediella Clerck. 相似文献
98.
Cecilia Lindström Olle Holst Per Hellstrand Rickard Öste Kristina E. Andersson 《Food Hydrocolloids》2012
Exopolysaccharides (EPS) are excreted by microorganisms into the surrounding environment and have been shown to have various physiological effects and are commonly used as food additives due to their rheological properties. Four commercially available microbial EPS with different polymeric structures and composition were tested in LDL receptor knock-out mice to investigate their effect on blood cholesterol, lipoproteins and caecal formation of SCFA. After four weeks on a Western diet supplemented with 4% EPS there were significant increases in caecal content and caecal tissue weight for the EPS groups compared to the control. The total pool of caecal short chain fatty acids was increased when mice were fed scleroglucan, xanthan and dextran. There were no differences in plasma cholesterol levels on the experimental diets compared to the control. Plasma triglycerides did not differ between groups. The results indicate that EPS supplementation to a Western diet may help in maintaining a healthy intestinal environment. 相似文献
99.
Ulf Jansson Erik LewinMikael Råsander Olle ErikssonBenny André Urban Wiklund 《Surface & coatings technology》2011,206(4):583-590
This paper reviews a series of studies on alloying of sputtered TiC coatings with weak carbide-forming metals, Me, such as Al, Fe, Ni, Pt and Cu. Metastable solid solutions with Me on the Ti sites are easily obtained by magnetron sputtering at low temperatures (< 300 °C). First principles density functional theory (DFT) calculations of such carbides show that a driving force exists to remove carbon from the structure as an alternative and kinetically more favourable route compared to Me precipitation. This leads to a situation where additional control of the phase composition is given by annealing: both direct influence during film growth, as well as through subsequent annealing. Thus, alloying of the nanocomposite with weak carbide-forming metals can be used to tune many mechanical, electric and magnetic properties of a carbide-based nanocomposite film. 相似文献
100.
We explore the lyotropic phase behaviour of dilute, aqueous amyloid fibril dispersions from hen egg white lysozyme with respect to protein and acid concentration in order to establish preparation protocols that provide homogeneous nematic phases. Such ordered dispersions are demonstrated to facilitate alignment of amyloid nanofibrils in thin solid films, which are utilised to structure conjugated (poly)electrolytes. In addition, the occurrence of ordered phases is found to be in good qualitative agreement with phase equilibria predicted for dispersions of rod-like particles. 相似文献