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   124篇
  免费   1篇
林业   11篇
农学   4篇
基础科学   2篇
  35篇
综合类   5篇
农作物   4篇
水产渔业   12篇
畜牧兽医   40篇
园艺   8篇
植物保护   4篇
  2023年   1篇
  2022年   1篇
  2021年   2篇
  2020年   3篇
  2019年   3篇
  2018年   3篇
  2016年   4篇
  2015年   2篇
  2014年   5篇
  2013年   20篇
  2012年   12篇
  2011年   8篇
  2010年   8篇
  2009年   7篇
  2008年   7篇
  2007年   6篇
  2006年   10篇
  2005年   3篇
  2004年   2篇
  2003年   2篇
  2002年   2篇
  2001年   2篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1994年   1篇
  1993年   1篇
  1988年   2篇
  1987年   1篇
  1984年   1篇
  1976年   1篇
排序方式: 共有125条查询结果,搜索用时 15 毫秒
81.
82.
Buruk K  Sokmen A  Aydin F  Erturk M 《Fitoterapia》2006,77(5):388-391
The Eastern Black Sea Region has an extensive flora because of ample rainfall lasting all year. In this study, antimicrobial effects of 74 crude extracts of 22 endemic plants were investigated. Among the 30 active crude extracts, water-insoluble crude extracts from Betula medwediewii, Heracleum platytaenium, Primula longipes, Anthemis cretica ssp. argaea and Centaurea helenioides were the prominent ones with their MIC values.  相似文献   
83.
In order to simulate soil suction and soil temperature, a field study was carried out in the experimental farm of the Agricultural Faculty, University of Cukurova (Adana/TURKEY), for a period of two years. During this period the soil was bare. Data collected regularly include soil suction and soil temperature. Meteorological data were obtained from the Adana Climatological Station. Data on soil suction and soil temperature were used to calibrate the simulation model, proposed by Huwe and van der Ploeg (1988). It was found that the model, after having been calibrated, performed quite well. A fair agreement between measured and simulated soil temperatures was obtained. However, the calculated and measured soil suction values were found to be considerably different. The simulation model used in this study appears to be applicable for the conditions of the Cukurova Region in Southern Turkey.  相似文献   
84.
Growth performance, carcass characteristics, post-slaughtering and haematological parameters of Kivircik and Karacabey Merino male lambs in conventional and organic management systems were compared. The animals which were weaned at 7 weeks of age were divided into Kivircik conventional, Kivircik organic (KO), Karacabey Merino conventional and Karacabey Merino organic (MO) groups containing 12 lambs each. Fattening was ended when lambs attained 35 kg of live weight. The time to attain the determined fattening weight was significantly different among the groups, and Merino lambs having higher live weight gain were earlier than Kivircik lambs (p?相似文献   
85.
A feeding trial was performed to assess the potential beneficial effect of two levels of mannanoligosaccarides (MOS) on the growth performance, feed utilization, hematological parameters, and liver histopathology of gilthead seabream Sparus auratus (also known as gilthead bream). Mannanoligosaccarides were added at the rates of 2 and 4 g/kg to a fish-meal-based control diet, and each diet was given (twice daily [midmorning and midafternoon] to apparent satiation) to triplicate groups of gilthead seabream growers (mean weight = approximately 170 g) in sea cages. The trial lasted 12 weeks, and the average ambient water temperature ranged from 19.6 degrees C to 24.7 degrees C during the experimental period. At the end of the experiment, fish attained market size (350-450 g) and their health status was evaluated by blood analysis and liver histology. There were no differences in survival rates among fish fed experimental diets. However, there were significant improvements in both growth and feed utilization among fish fed diets supplemented with MOS. Hemoglobin (Hb) and hematocrit (Ht) levels and erythrocyte, leukocyte, and thrombocyte (Thr) counts were unaffected by any dietary MOS. The levels of Hb (g/dL; mean +/- SD) and Ht (%; mean +/- SD) were 11.0 +/- 2.5 and 45.6 +/- 6.7 for the control group, 11.1 +/- 1.7 and 39.3 +/- 8.0 for the 2-g/kg group, and 11.2 +/- 1.9 and 40.2 +/- 8.4 for the 4-g/kg group. The mean Thr count ranged from 47.6 to 53.8 x 10(3)/mm3. Despite the apparently higher Thr counts for fish fed diets supplemented with MOS, these differences were not significant. Moreover, no histopathological differences were observed in liver tissue cross sections between control and treatment groups. These results suggest that supplementation of diets with MOS had no significant effects on general fish health.  相似文献   
86.
The objective of this study was to determine the antibiotic susceptibility of Arcobacter spp. isolated from various sources. Seventy Arcobacter spp. isolates were tested for their susceptibility to 13 antimicrobial agents. Antimicrobial susceptibility testing was performed by using the agar disc diffusion method on Mueller-Hinton agar supplemented with 5% defibrinated sheep blood. The antibiotics tested included enrofloxacin, erythromycin, streptomycin, gentamycin, rifampin, tetracycline, ampicillin, trimethoprim/sulfamethoxazole, nalidixic acid, danofloxacin, amoxycillin-clavulonic acid, cefuroxime-sodium, neomycine. Although all the arcobacters tested were susceptible to gentamycin, resistance to three or more antibacterial agents (especially, trimethoprim/sulfamethoxazole, cefuroxime-sodium and rifampin) was observed. A. butzleri isolates were found to be resistant to amoxycillin+clavulonic acid, nalidixic acid and ampicillin, at the rate of 20%, 44.28% and 78.57% respectively. In conclusion, gentamycin, streptomycin and tetracycline may be suitable antibiotics for the treatment or control of disease caused by Arcobacter spp. in veterinary and human medicine.  相似文献   
87.
This research was carried out in order to determine the effect of zinc (Zn) application on the available iron (Fe) contents of calcareous soils in Thrace Region. For this purpose, an experiment was carried out in greenhouse conditions by maize growing. The effect of increasing rates of Zn application on the biological indices of maize plant was determined. Fe concentration of maize plant decreased with Zn application and dry matter yield and Fe uptake of maize plant increased with Zn application. These decreases and increases were determined to be statistically significant (P<0.01).  相似文献   
88.
Two cultivars of lettuce plants (Lactuca sativa L. cvs Berlo and Kirsten) were grown for two months in late fall in NFT under three different nitrogen (N)‐regimes but with the same total N concentration (13.4 mM). A reference treatment with a nutrient solution containing 94% nitrate (NO3) and 6% ammonium (NH4) was compared with urea and proteinate treatments in which 20% of the NO3 of the reference treatment was replaced by either of these two N sources. Proteinate is a fertilizer produced in Turkey containing 8% amino acid N and 8% NO3‐N. For both cultivars the fresh weights of the harvested plants were unaffected by the N source as was also the total N uptake. Nitrate content, however, was considerably lower in the urea and proteinate plants, values for the three treatments ranging from 3314 to 4579 mg NO3/kg fresh wt making up from between 44.3% to 55.4% of the total plant N. Of the two cultivars, Berlo accumulated greater concentrations of NO3 than did Kirsten. The accumulation of chloride (Cl) was in the reverse order of that of NO3 with greatest concentrations occurring in the proteinate plants.  相似文献   
89.
The most practical and effective method to increase dry matter production in rangelands is by adequate fertilization. N and K fertilizers have commonly been used worldwide to increase yield in rangelands. Fertilizers have a significant effect on mineral concentration in the forage. Risk of tetany, causing yield decrease and death in cattle, increases by feeding forage with a ratio of K/(Ca + Mg) ≥ 2.2. The fertilizers containing N and K are the most important factors increasing K/(Ca + Mg) ratio in forages. The present study has aimed to determine whether the tetany risks caused by K and N fertilization may be compensated by Mg fertilization. For this purpose, N (0 and 120 kg ha−1), K (0 and 100 kg ha−1) and Mg (0 and 30 kg ha−1) were applied as combinations of each other. Each plot was separated into three sub-plots sampled on 25 April, 15 May and 5 June to determine Ca, Mg, K concentrations and K/(Ca + Mg) ratio.In this 2-year study, dry matter production in the control plot was 2064 kg ha−1 and nitrogen application increased the dry matter production of the plots by about 100%. Dry weight ratios of grasses increased while legume dry weight ratios decreased drastically in response to N fertilization. An increase was observed in K/(Ca + Mg) ratio with N fertilization due to the fact that legumes have higher concentrations of Ca and Mg than grasses. K fertilization resulted in an approximately 30% increase of K concentration in dry matter. K/(Ca + Mg) ratio in plots where N and K were applied separately was lower than 2.2. However, K/(Ca + Mg) ratio in plots to which N and K were applied in combination was over 2.2, resulting in tetany risk. It is interesting to determine that Mg fertilization did not change Mg concentration in pasture. It was noted that tetany risk did not decrease with the advance of harvest dates. The results indicated that tetany risk caused by N and K fertilizations could not be compensated by Mg treatment. Therefore, it can be concluded that fertilization programmes avoiding legume decrease in rangelands may be useful to prevent the tetany risk.  相似文献   
90.
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