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   84篇
  免费   5篇
林业   4篇
农学   4篇
基础科学   3篇
  17篇
综合类   4篇
农作物   12篇
水产渔业   8篇
畜牧兽医   26篇
园艺   1篇
植物保护   10篇
  2023年   1篇
  2021年   2篇
  2019年   1篇
  2017年   1篇
  2016年   1篇
  2015年   2篇
  2014年   3篇
  2013年   4篇
  2012年   1篇
  2011年   7篇
  2010年   6篇
  2009年   4篇
  2008年   5篇
  2006年   1篇
  2005年   2篇
  2004年   3篇
  2003年   2篇
  2002年   2篇
  2001年   3篇
  2000年   1篇
  1999年   3篇
  1998年   1篇
  1997年   1篇
  1996年   2篇
  1988年   4篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1981年   2篇
  1980年   3篇
  1979年   3篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
  1971年   1篇
  1969年   4篇
  1968年   1篇
  1967年   3篇
排序方式: 共有89条查询结果,搜索用时 31 毫秒
21.
An increase of 11–31% of dry mycelial mass was observed along with a slight decrease (5–10%) in aflatoxin Bi production in 5-day-old aflatoxigenicAspergillus spp. submerged cultures containing either 0.5 ml or 1.0 ml clarified neem oil (CNO) in 0.1 % Triton solution. Fungal growth and aflatoxin B1 production were also determined in potato-dextrose-agar petri plate cultures inoculated with aflatoxigenicAspergillus spp. containing an atmosphere of volatiles emitted from 0.25 ml, 0.5 ml, and 1.0 ml CNO added to the plates. After 5 days’ incubation, fungal radial growth was reduced by 7–29% and aflatoxin B1 production by 0–67%. GC/MS analysis of the head space volatiles of the CNO indicated that the reduction of fungal growth and aflatoxin B1 was probably due to low molecular weight hydrocarbons, aldehydes, alcohols, and sulfur compounds emitted at 30°C in the dry culture. These results suggest that volatiles emitted from CNO at 30° C in plate cultures were more fungistatic and consequently inhibited aflatoxin production more than neem oil added in liquid cultures.  相似文献   
22.
Ultrastructural studies were conducted on the myocardium of rats fed corn oil, Tower RSO (0 . 88 per cent EA), 1788 RSO (3 . 6 per cent EA) and Target RSO (38 . 9 per cent EA) supplemented diets for 18 weeks. Cardiac myocytes of Tower RSO-fed rats showed some loosening of myofibrils and a slight increase in the number of mitochondria, few of which had lost their cristae. Large intravascular lipid droplets were observed in the myocardium of rats fed the 1788 RSO diet, as well as some small lipid droplets which were seen in close association with mitochondria. There was an apparent increase in the number of mitochondria of both normal and giant size. Many of the mitochondria exhibited distortion of shape and degeneration of cristae. The matrix of megamitochondria contained vesicles and electron-dense floccular inclusions and at times electron-lucent lipid-like material. The degenerative changes of mitochondria were most pronounced in the Target RSO group, where some megamitochondria showed a complete loss of cristae and a replacement of matrix with lipid-like material. These observations suggest that both intravascular lipid globules and the mitochondrial alterations are possible contributory factors involved in the development of cardiac lesions in RSO-fed rats.  相似文献   
23.
Bluegill fish, following exposure to [14C]photodieldrin eliminated 50% of the absorbed radioactivity in 3 weeks. Analysis of the products revealed that about 27% of the eliminated radioactivity was due to the unaltered photodieldrin while the rest consisted of at least 11 metabolites in free and conjugated forms. Photodieldrin ketone was the major excretory product. Solvent extracts of the whole fish examined showed 4 metabolites in addition to about 90% of the unmetabolized photodieldrin. The ketone derivative was the most predominant of the metabolic products.  相似文献   
24.
25.
The present studies were conducted to isolate, select, identify and characterize gut bacteria as antimicrobial and growth promoting agent for the feed of economical y important ifsh Cirrhinus mrigala. ...  相似文献   
26.
Two experiments were conducted to investigate the effect of inland water salinity on growth performance, feed conversion efficiency and intestinal enzyme activity in grey mullet. In experiment I, a 90 day monoculture of grey mullet at different salinity levels (0, 10, 15, 20 and 25%) was carried out. The fingerlings were stocked at 5000 per hectare and fed on a supplementary diet at 5% BW d–1. This Study revealed that fish growth mean body weight (90.5 ± 4.5 g) and mean length (21.6 ± 0.4 cm), SGR (4.70%) and growth per day (0.99 g d–1) were significantly (p < 0.05) enhanced in fish maintained at 10% salinity in comparison with other treatments. Nutrient levels, phytoplankton population, NPP and chlorophyll a all decreased with an increase in salinity (>10%). In addition, zooplankton populations increased with an increase in the salinity level. Most of the other hydrochemical characteristics remained at optimal levels in all other treatments. Fish weight gain showed a significant positive correlation with productivity indicating parameters viz. alkalinity (r = 0.53), turbidity (r = 0.62), NPP (r = 0.75) and chlorophyll a (r = 0.46), clearly revealing that fish growth is also related to the trophic status of the ponds. In the second experiment (Experiment II), mullet fry were exposed to five different salinity levels (10, 15, 20, 25 and 30%) and maintained for 70 days in the laboratory. Significantly (p < 0.05) high growth, (SGR and per cent increase in body weight), feed conversion efficiency and intestinal enzyme activity were observed in the group maintained at 10 salinity in comparison with other groups maintained at similar salinity levels. Carcass composition, musc1e and liver glycogen levels were also significantly (p < 0.05) affected by salinity changes.  相似文献   
27.
Kumar  Raj  Bhardwaj  A. K.  Rao  B. K.  Vishwakarma  A. K.  Kakade  Vijaysinha  Dinesh  D.  Singh  Gaurav  Kumar  Gopal  Pande  V. C.  Bhatnagar  P. R.  Bagdi  G. L. 《Journal of Soils and Sediments》2021,21(2):1232-1242
Journal of Soils and Sediments - Soil erosion and loss threatens vast tracts of agricultural and non-agricultural land, worldwide. High soil erosion severely affects establishment of vegetation via...  相似文献   
28.
Over the last few years, significant research has been conducted in the construction of artificial bone scaffolds. In the present study, different types of polymer scaffolds, such as chitosan-alginate (Chi-Alg) and chitosan-alginate with fucoidan (Chi-Alg-fucoidan), were developed by a freeze-drying method, and each was characterized as a bone graft substitute. The porosity, water uptake and retention ability of the prepared scaffolds showed similar efficacy. The pore size of the Chi-Alg and Chi-Alg-fucoidan scaffolds were measured from scanning electron microscopy and found to be 62–490 and 56–437 µm, respectively. In vitro studies using the MG-63 cell line revealed profound cytocompatibility, increased cell proliferation and enhanced alkaline phosphatase secretion in the Chi-Alg-fucoidan scaffold compared to the Chi-Alg scaffold. Further, protein adsorption and mineralization were about two times greater in the Chi-Alg-fucoidan scaffold than the Chi-Alg scaffold. Hence, we suggest that Chi-Alg-fucoidan will be a promising biomaterial for bone tissue regeneration.  相似文献   
29.
Rice, grown on a wide range of soils with varying soil pH levels boron (B) availability, uptake and mobilization could be limiting hence may lead to lower productivity and rice yields has been tested at 11 locations on low yielding rice genotypes from, Initial Evaluation Trials (IET) of AICRIP viz.IET 20979, IET 21003, IET 21007, IET 21014, IET 21025 and Rasi as check variety. Active boron supplemented as foliar spray at anthesis stage at 0.2, 0.4 and 0.8 ppm. Grains with 1.20 (High density), and 1.06 (normal density) specific gravity (sp. gr.) and unfilled grains were determined. The results showed that application of boron resulted in increase in grain number (25–45) and reduced the number of unfilled spikelets. At majority of the locations, application of 0.4 ppm boron had resulted in significant increase in grain yield (4–8%). Cultures, IET 20979, IET 21007, and IET 21014 showed a positive response with the 0.4 ppm application at the majority of locations.  相似文献   
30.
In vitro direct plant regeneration of lucerne was achieved by simultaneous application of thidiazuron (TDZ) and 6‐benzyladenine (BA) in Murashige and Skoog (MS) medium. Seedlings were germinated and grown for 6 d on growth regulator–containing MS medium. The shoot tip, consisting of the apical meristem along with parts of the cotyledonary leaves and hypocotyl, was then cultured on a medium containing the growth regulator(s). Adventitious budding of the shoot tip was promoted synergistically by treatment with TDZ and BA, and a maximum of thirty‐five shoots per explant was obtained on a medium supplemented with 2 mg L?1 TDZ and 1 mg L?1 BA. Plant regeneration frequency varied from 67 to 93%, and five Indian lucerne cultivars responded well to the regeneration protocol. The Agrobacterium‐mediated transformation frequency from co‐cultivated explants was 13% following multiple shoot induction. Southern analysis of the T0 plants and T1 progenies confirmed stable inheritance of the hpt marker gene. Agrobacterium infection of the explant caused a significant reduction in the plant regeneration frequency (23%) and the number of shoots induced (11) when compared with uninfected explants. A single shoot tip provided sufficient material to regenerate and establish twenty‐seven lucerne plants, whereas only nine plants could be regenerated from an Agrobacterium co‐cultivated explant. This transformation protocol could represent a valuable improvement over existing ones for lucerne.  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