首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   127篇
  免费   11篇
林业   5篇
农学   4篇
  40篇
综合类   4篇
农作物   6篇
水产渔业   7篇
畜牧兽医   57篇
园艺   4篇
植物保护   11篇
  2022年   2篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2017年   5篇
  2016年   2篇
  2015年   8篇
  2014年   3篇
  2013年   33篇
  2012年   8篇
  2011年   7篇
  2010年   4篇
  2009年   3篇
  2008年   5篇
  2007年   9篇
  2006年   5篇
  2005年   6篇
  2004年   1篇
  2003年   7篇
  2002年   3篇
  2001年   2篇
  2000年   5篇
  1999年   2篇
  1992年   2篇
  1991年   2篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1983年   2篇
  1979年   2篇
  1966年   1篇
排序方式: 共有138条查询结果,搜索用时 15 毫秒
21.
Phenolic antioxidants from the leaves of Corchorus olitorius L.   总被引:3,自引:0,他引:3  
Six phenolic antioxidative compounds [5-caffeoylquinic acid (chlorogenic acid), 3,5-dicaffeoylquinic acid, quercetin 3-galactoside, quercetin 3-glucoside, quercetin 3-(6-malonylglucoside), and quercetin 3-(6-malonylgalactoside) (tentative)] were identified from the leaves of Corchorus olitorius L. (moroheiya) by NMR and FAB-MS. The contents of these phenolic compounds, ascorbic acid, and alpha-tocopherol in C. olitorius leaves were determined, and their antioxidative activities were measured using the radical generator-initiated peroxidation of linoleic acid. The results obtained showed that 5-caffeoylquinic acid was a predominant phenolic antioxidant in C. olitorius leaves.  相似文献   
22.
The effects of lipids, emulsifiers, and ethanol on the absorption of orally administered quercetin in rats were investigated for its efficient intestinal absorption. Rats were administered 150 micromol/kg quercetin in water supplemented with lipids and/or emulsifiers, or ethanol, and blood was collected from the tail for 6 h after administration. Co-administration of lipids such as lecithin and soybean oil or emulsifiers including sucrose fatty acid ester, polyglycerol fatty acid ester, and sodium taurocholate had no statistically significant effects on quercetin absorption, although these constituents rather increased the accumulation of conjugated forms of quercetin and those of isorhamnetin in rat plasma. However, the combination of lipids and emulsifiers enhanced the absorption of quercetin significantly. Thirty and fifty percent (v/v) of the ethanol in the vehicle raised the efficiency of quercetin absorption in a concentration-dependent manner. Quercetin absorption-enhancing effects of these constituents seemed to be affected by quercetin's solubility in respective vehicles used for the administration. Ethanol is not helpful for the effective absorption of quercetin, as a high concentration is required. In conclusion, a combination of lipids and emulsifiers is necessary for enhancing quercetin absorption.  相似文献   
23.
Feeding systems such as grazing affect the fatty acid profile of bovine milk fat. In addition, milk fat is formed as the product of fatty acid metabolism in cow bodies before being secreted into milk. However, how grazing influences milk fatty acid profile through the metabolism has not been completely characterized. When fatty acid concentrations in Holstein milk were compared between grazing and non‐grazing periods, α‐linolenic acid was significantly higher in the grazing period than in the non‐grazing period. This could be explained with an increase in α‐linolenic acid feeding with grazing. α‐linolenic acid had a linear positive correlation with conjugated linoleic acid (9c,11t‐18:2) (CLA) and vaccenic acid (VA) during the grazing period, whereas CLA had higher correlation with linoleic acid rather than with α‐linolenic acid during the non‐grazing period. These data indicate that the high content of dietary α‐linolenic acid affects CLA and VA formation in milk of grazing periods via α‐linolenic acid metabolism into VA.  相似文献   
24.
In the last report1) the purity of radioactive potassium. which had been produced by 41K (d, p) 42K nuclear reaction and separated from, radioactive anions by the use of ion exchange resin, was tested by means of its decay curve. By this test, it is difficult to distinguish 42K from 24Na contamination, because the half life of radioactive sodium (24Na) is 15.06 hours2) and it is very similar to that of radioactive potassium (42K) which is 12.4 hours. When the nuclear reaction 23Na (d, p) 24Na occurs, the cross section of this reaction for deuterons is about 100 times that of potassium nuclear reaction. In this case the purity of radioactive potassium (42K) could be confirmed by its Gamma-ray spectrum. According to the result, radioactive potassium of high purity was obtained. Potassium phosphate which was double-labeled by this radioactive potassium and imported radioactive phosphorus (32P) was applied to leaves or roots of bean plants.  相似文献   
25.
Active surface agents are often added to spray solutions to facilitate the uniform wetting and coveringg of the leaf surfaces1),2). Some have reported that the addition of active surface agents increased the absorption of nutrients, but others have reported different results.  相似文献   
26.
In the preceding paper (1), it was reported that even under aerobic shaking conditions, if R. capsulatus were mixed with Bacillus megaterium, the bacterial growth of both and nitrogen fixation were accelerated remarkably.  相似文献   
27.
Mitigation of nitrous oxide (N2O) emission from swine wastewater treatment was demonstrated in an aerobic bioreactor packed with carbon fibers (CF reactor). The CF reactor had a demonstrated advantage in mitigating N2O emission and avoiding NOx (NO3 + NO2) accumulation. The N2O emission factor was 0.0003 g N2O‐N/gTN‐load in the CF bioreactor compared to 0.03 gN2O‐N/gTN‐load in an activated sludge reactor (AS reactor). N2O and CH4 emissions from the CF reactor were 42 g‐CO2 eq/m3/day, while those from the AS reactor were 725 g‐CO2 eq/m3/day. The dissolved inorganic nitrogen (DIN) in the CF reactor removed an average of 156 mg/L of the NH4‐N, and accumulated an average of 14 mg/L of the NO3‐N. In contrast, the DIN in the AS reactor removed an average 144 mg/L of the NH4‐N and accumulated an average 183 mg/L of the NO3‐N. NO2‐N was almost undetectable in both reactors.  相似文献   
28.
During the experimental study of the role of blue-green algae in the nitrogen economy of paddy fields which were hitherto carried out in our laboratory, it was observed that small animals in paddy fields such as water fleas, mud snails, small freshwater fish, tadopoles or larvae of small insects had a preference for feeding on blue-green algae.  相似文献   
29.
In the preceeding paper (1), it was reported that when R. capsulatus is mixed with B. subtilis, in spite of no nitrogen fixation in separate cultures, by using a glycerol or starch medium, the combination was able to fix molecular nitrogen and it seems that there is a correlation between the production of pyruvic acid and the nitrogen fixation in the mixed culture.  相似文献   
30.
We evaluated the anti-tumor activities of the oral administration of fucoidan extracted from Cladosiphon okamuranus using a tumor (colon 26)-bearing mouse model. The materials used included low-molecular-weight fucoidan (LMWF: 6.5–40 kDa), intermediate-molecular-weight fucoidan (IMWF: 110–138 kDa) and high-molecular-weight fucoidan (HMWF: 300–330 kDa). The IMWF group showed significantly suppressed tumor growth. The LMWF and HMWF groups showed significantly increased survival times compared with that observed in the control group (mice fed a fucoidan-free diet). The median survival times in the control, LMWF, IMWF and HMWF groups were 23, 46, 40 and 43 days, respectively. It was also found that oral administration of fucoidan increased the population of natural killer cells in the spleen. Furthermore, from the results of the experiment using Myd-88 knockout mice, it was found that these effects are related to gut immunity. These results suggest that fucoidan is a candidate anti-tumor functional food.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号