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   58篇
  免费   2篇
  国内免费   1篇
  2023年   1篇
  2022年   3篇
  2021年   3篇
  2018年   2篇
  2017年   1篇
  2016年   4篇
  2015年   3篇
  2014年   3篇
  2013年   12篇
  2012年   2篇
  2011年   2篇
  2009年   1篇
  2008年   1篇
  2007年   2篇
  2005年   3篇
  2004年   2篇
  2002年   4篇
  1999年   2篇
  1996年   1篇
  1993年   1篇
  1991年   1篇
  1989年   1篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1980年   1篇
  1977年   1篇
排序方式: 共有61条查询结果,搜索用时 31 毫秒
1.
Spleen cells from rats immunized with the syngeneic (C58NT)D Gross virus induced lymphoma have previously been shown to differentiate into cytotoxic effector cells following restimulation with tumor cells in vitro. Previous work has also demonstrated that the addition of PPD-primed syngeneic spleen cells and PPD to cultures of (C58NT)D-primed spleen cells will potentiate the in vitro cytotoxic response to tumor antigens. In the studies presented here, the potentiating effect was found to be mediated by a soluble factor(s) released by nonadherent cells from BCG-primed rats. The release of this immunopotentiating factor(IPF) required the presence of PPD and varied with the concentration of PPD added. IPF was produced by BCG-primed spleen, lymph node, and thymus cells. Maximal production of IPF in PPD-stimulated cultures was obtained after 6–12 hr of incubation. Supernatants obtained after 30 hr of incubation lacked apparent IPF activity when tested initially, but activity was recovered after mild heat treatment. Recovery of IPF activity after heat exposure is best explained by the presence of a heat-labile inhibitor. IPF itself is stable to heat treatment to 56 °C for 40 min. IPF was also shown to be capable of enhancing immune responses to histocompatibility antigens in vitro.  相似文献   
2.
Pot experiments laid out in a complete randomised design were conducted in the screen house of the Department of Crop Protection, University of Agriculture, Abeokuta, Ogun State, Nigeria to determine the effects of organic fertiliser and Chromolaena odorata residue at 1% w/w on the pathogenicity of Meloidogyne incognita infecting maize. M. incognita significantly reduced the plant height, number of leaves per plant, leaf area, cob weight and grain yield of maize by 6.89, 15.18, 20, 63.92 and 56.16% respectively. C. odorata residue and organic fertiliser significantly suppressed M. incognita galling, inhibited the nematode fecundity and reduced the number of eggs and juveniles on maize. A remarkable increase in plant height, number of leaves per plant, leaf area, cob weight and grain yield were observed on maize plants treated with the mixture of C. odorata and organic fertiliser despite the nematode infection. The observation from this study suggests that C. odorata in combination with organic fertiliser is a viable option for the control of M. incognita on maize.  相似文献   
3.
A field survey was conducted in eight local government areas (LGA) of Ogun state, Nigeria to assess the incidence of viral diseases of yams in the areas. Leaf samples were collected from 90 yam plants which were either symptomatic or asymptomatic. These were bulked into 45 during serological tests and the viruses indexed include yam mosaic virus (YMV); Dioscorea alata bacilliform virus (DaBV) and cucumber mosaic virus (CMV). DaBV was the most prevalent virus on the field with incidence of 48.9% (22/45) followed by YMV which occurred in 42.2% (19/45). CMV had the lowest percentage of incidence; 2.2% (1/45). Of all the LGAs visited, Abeokuta north and Abeokuta south had the highest incidence of YMV and DaBV, respectively. Mixed virus infections were also detected.  相似文献   
4.
The microbial composition of the frass from maize (Zea mays) grains and seven dried root and tuber crops (R&TC) infested by Prostephanus truncatus were evaluated. Five cubes (6 cm3) of each R&TC as well as 100 g of maize grains were separately infested with 15 pairs of 1–2 day old adult LGB in 250 cm3 sized Kilner jars and incubated for 90 days at 28 ± 1°C and 79–82% RH. At 90 days post-infestation, the microbiological assay of frass from the commodities was performed. The results indicated the presence of 10 bacterial species, namely Bacillus cereus, B. macerans, Proteus mirabilis, P. morganic, P. rettgeri, Proteus sp., Pseud geniculatum, Pseud fragii, Pseud putela, Serratia marcences and six fungal species, namely Aspergillus niger, A. tamari, A. parasiticus, A. ochraceus, Fusarium compacticum and F. oxysporum. Infested cubes of M. esculenta have the highest population of adult LGB (168.3) and frass from its damaged cubes had the highest mean bacterial count of 30.0 × 107 colony forming units (CFU) and it was significantly (P < 0.05) higher than LGB infestation and bacterial infection of other R&TC. The bacterial count from the damaged commodities correlated positively and significantly (P < 0.05) with weight of frass, percentage damage and percentage weight loss. The results revealed that frass from the LGB-infested and damaged commodities were infected by bacteria and fungi. Maize grains and dried R&TC should therefore be protected from LGB infestation to avoid quantity reduction and microbial infection.  相似文献   
5.
Meloidogyne incognita infestation on maize results in heavy yield loss in farmers’ field. Most of the varieties adopted by subsistence farmers in Nigeria are susceptible to M. incognita. Beside these, the cost of control exceeding the profit from the crop using nematicides and the pollution risk they pose to the environment has necessitated the need for alternatives. Pot and field experiments were, therefore, conducted to investigate the effects of Chromolaena odorata powder and Glomus mosseae (a mycorrhizal fungus) on M. incognita pathogenicity on maize. Hybrid Oba super II improved maize variety adopted by local farmers was selected for the study. Maize plants were grown with G. mosseae (5 spores/g of soil) and soil amended with C. odorata powder (1% w/w) singly and in combination. Two weeks after emergence, Test plants were inoculated with 5000 M. incognita eggs. Sixty days after planting, destructive samples were assessed for root gall symptom and severity, and nematode population. Results show that G. mosseae and C. odorata powder were effective in controlling the population of M. incognita and the root knot nematode symptom and gave the highest yield parameters in combination. Single application of G. mosseae and C. odorata powder was similar in the effect on M. incognita and maize yield. Combination of G. mosseae and C. odorata powder may become a viable alternative to nematicide in managing M. incognita pathogenicity on maize as C. odorata powder may serve as a carrier medium for G. mosseae.  相似文献   
6.
The ability of Streptomyces sp. OXCI, S. rimosus NRRL B2659, S. rimosus NRRL B2234, S. alboflavus NRRL B1273 S. aureofaciens NRRL B2183 and S. vendagensis ATCC 25507 to produce tetracycline using some local agricultural wastes as solid state media, were assessed. The wastes employed include peanut (groundnut) shells, corncob, corn pomace and cassava peels. Bacillus subtilis ATCC 6633 was used to assay antimicrobial activity. All the strains produced tetracycline in a solid-state fermentation process containing peanut (groundnut) as the carbohydrate source. Streptomyces sp. OXC1 had the highest ability for tetracycline production with peanut shells as the substrate in solid fermentation (13.18 mg/g), followed by S. vendagensis ATCC 25507 (11.08 mg/g), S.rimosus NRRL B1679 (8.46 mg/g), S. alboflavus NRRL B1273 (7.59 mg/g), S. rimosus NRRL B2234 (6.37 mg/g), S. aureofaciens NRRL B2183 (4.27 mg/g). Peanut (groundnut) shells were the most effective substrate (4.36 mg/g) followed by corncob (2.64 mg/g), cassava peels (2.16 mg/g) and corn pomace (1.99 mg/g). The composition of the peanut (groundnut) shell medium optimal for tetracycline production were peanut shells 100 g, organic nitrogen (peanut meal) 10 g, (NH 4)2 SO4 1 g, KH2 PO 4 0.5 g, CaCO3 > 0.5 g, NaCl 0.5 g, MgSO4 · 7H2 O 0.5 g, soluble starch 10 g, peanut oil 0.25 ml with initial moisture content of 65–68%, and initial pH 5.3–6.3. Substrate (1 g dry weight) was inoculated with 1.0 × 10 8 conidia per ml and incubated at 28–31 °C for 5–7 days, producing 13.18 mg/g of total tetracycline. Tetracycline detection started on day 3 and attained its maximum level on day 5.  相似文献   
7.
An outbreak of Streptococcus pyogenes infection occurred in a colony of 800 Dunkin-Hartley guinea pigs resulting in 364 (46%) deaths involving breeders, sucklings, weaners, but mainly adults used as a source of blood meals for haematophagus flies (Glossina palpalis). Clinical signs included bleeding from the nose, mouth and vagina before death. Necropsy revealed pneumonia with consolidation of one or both lungs, haemopericardium and haemothorax. There were yellowish-grey deposits in the urinary bladder of more than 50% of both affected breeders and adults used for feeding haematophagus flies. Beta-haemolytic Streptococcus pyogenes was isolated in pure culture from many tissues including the urinary bladder. The survivors were treated with oxytetracycline (Terramycin-LA; Pfizer) using the intra-muscular route and the response was good.  相似文献   
8.
Biscuits are flour-based products,which areconsumed by majority of people,both old and young,throughout the world and most especially by children,teenagers and mid-adults(Majumder,1970).It can beserved as a desert or snacks and as a breakfast foodwhentaken with beverages.Its ready-to-serve state andlong shelf life contribute to its acceptability by themasses.Wheat as humanfoodis used principallyintheformof flour for baked products such as bread,bis-cuits,pastries and crackers(Kent,1983).In th…  相似文献   
9.
Anaemia in falciparum malaria is associated with an increased risk of gametocyte carriage, but its effects on transmission have not been extensively evaluated in malarious children. Plasmodium falciparum gametocyte carriage, emergence, clearance, population sex ratios (SR) (defined as the proportion of gametocytes that are male), inbreeding rates and temporal changes in SR were evaluated in 840 malarious children. Gametocyte carriage pre-treatment was at a level of 8.1%. Anaemia at enrolment was an independent risk factor for gametocyte carriage post-treatment. The emergence of gametocytes seven days post-treatment was significantly more frequent in anaemic children (7/106 vs. 10/696, p = 0.002). In the initially detected gametocytes, the proportion of children with a male-biased SR (MBSR) (> 0.5) was significantly higher in anaemic children (6/7 vs. 3/10, p = 0.027). Pre-treatment SR and estimated inbreeding rates (proportion of a mother's daughters fertilised by her sons) were similar in anaemic and non-anaemic children. Pre-treatment SR became more female-biased in non-anaemic children following treatment. However, in anaemic children, SR became male-biased. Anaemia was shown to significantly increase gametocyte emergence and may significantly alter the SR of emerging gametocytes. If MBSR is more infective to mosquitoes at low gametocytaemia, then these findings may have significant implications for malaria control efforts in endemic settings where malaria-associated anaemia is common.  相似文献   
10.
There has been a sharp rise in the global prevalence of diabetes, obesity, and their comorbid conditions within the last decade prompting significant research into possible causes and cure via therapeutic intervention and lifestyle adjustments. Here, the molecular bases of antidiabetic plants used in the prehistorical treatment of diabetes and obesity are reviewed with particular focus on saponin as the phytotherapeutic principle. Until recently, the phytotherapeutic potentials of saponins have been masked in the heterogeneity of phytochemicals co-extractable during traditional preparations. With improved technique of purification and cutting edge biological assay methods, saponins have emerged as a regulator of primary biofuel availability through direct interaction with energy metabolism, cell signaling, and gene expression. Specific cases of lipoprotein lipase/peroxisome proliferator-activated receptor (PPAR)-gamma/phosphatidylinositide 3-kinase (PI-3-K)/protein kinase B (Akt) activation, adiponectin gene upregulation, fatty acid binding protein 4 repression (FABP4), and glucose transporter type 4 (Glut4) membrane exocytosis have been documented which provide molecular basis for hypocholesterolemic, hypoglycemic, and anti-obesity manifestations observed in experimental animals following saponin treatment. Although intensified research is required to characterize the pharmacophoric features in saponins exhibiting these interactions, however, this preliminary lead is valuable if the world will be free of diabetes, obesity, hypertension, hyperlipidemia, and atherosclerosis in no distant future.  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