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   114篇
  免费   8篇
林业   15篇
农学   7篇
  29篇
综合类   7篇
农作物   2篇
水产渔业   3篇
畜牧兽医   32篇
园艺   1篇
植物保护   26篇
  2023年   1篇
  2022年   3篇
  2021年   7篇
  2020年   7篇
  2019年   4篇
  2018年   9篇
  2017年   10篇
  2016年   8篇
  2015年   4篇
  2014年   6篇
  2013年   9篇
  2012年   6篇
  2011年   7篇
  2010年   7篇
  2009年   5篇
  2008年   7篇
  2007年   2篇
  2006年   1篇
  2005年   1篇
  2004年   1篇
  2003年   4篇
  2002年   2篇
  2001年   2篇
  2000年   2篇
  1997年   2篇
  1991年   1篇
  1987年   1篇
  1985年   1篇
  1967年   1篇
  1893年   1篇
排序方式: 共有122条查询结果,搜索用时 31 毫秒
21.
Tropical Animal Health and Production - This study examined rumen fermentation, histological, blood, and urinary characteristics as well as ammoniacal nitrogen concentration, pH, nitrogen balance,...  相似文献   
22.
European Journal of Plant Pathology - Brown eye spot (Cercospora coffeicola) is one of the main diseases of coffee (Coffea arabica L.) and represents a serious phytosanitary problem for the crop....  相似文献   
23.
A neurological syndrome in dairy cattle associated with consumption of moldy beer residues is described. The disease occurred on 1 farm in late June 2001, during winter. Six heifers and 1 cow out of 45 cattle were affected during a 3-week period. The affected animals died spontaneously or were euthanized approximately 2-14 days after the onset of clinical signs. The clinical signs were characterized by flaccid paralysis and gait abnormalities. Clinical signs were more pronounced after exercise and included stiff and unsteady gait, knuckling at the fetlocks of the hind limbs, frequent falling, inability to rise, muscular tremors, especially of the head and the hindquarters, and drooling. Main necropsy findings included degenerative and necrotic changes of the larger medial muscle groups of the hindquarters, i.e., adductor, pectineus, quadriceps femoris, rectus femuris, sartorius, semimembranosus, semitendinosus, and vastus medialis, and of the forequarters, including pectoralis descendens, pectoralis ascendens, and transversus pectoralis. The main histologic findings consisted of degenerative and necrotic neuronal changes (chromatolysis) of varying severity and extent affecting selected nuclei of the brainstem and neurons of the ventral horns of the spinal cord. Similar microscopic lesions were observed in the neurons of the spinal cord of 1 experimental sheep force-fed for 35 days with 1 kg/day of the same batch of foodstuff that was originally fed to the cattle. Coarse white or gray lumps, interpreted as mycelia, were observed in the beer by-product. Aspergillus clavatus was the dominant fungus isolated. Deaths ceased after the consumption of beer residue was discontinued. Recovery from illness was observed in 1 animal. The diagnosis was based on epidemiological data, clinical signs, necropsy findings, histological lesions, dosing trial, and mycology. A similar condition caused by consumption of barley by-products, sprouted wheat, corn sprouts, and beetroot screenings contaminated with A. clavatus has been reported in cattle and sheep worldwide.  相似文献   
24.
This study aimed to evaluate the effects of forage neutral detergent fiber (fNDF) levels on the voluntary feed intake, digestibility, ruminal fermentation and feeding behavior of goats fed diets with cactus pear. Five non‐lactating ruminally cannulated goats fed ad libitum were randomly assigned to a 5 × 5 Latin square design. Treatments consisted of levels of fNDF at 0, 109, 222, 339 and 463 g/kg of dry matter (DM) in cactus pear‐based diets. The intakes of DM and NDF were quadratically affected (p ≦ .045) by fNDF levels. Voluntary water intake (VWI) increased linearly as the fNDF levels increased in the diet. The digestibility coefficients of organic matter, NDF and ether extract and total digestible nutrients concentration were quadratically affected (p ≦ .048) by fNDF levels. The ruminal pH linearly increased (p = .001) with fNDF levels, ranging from 5.44 to 5.81 for diets containing 0 and 463 g fNDF/kg DM, respectively. The fNDF levels promoted a linear increase (p = .006) in chewing time, linearly decreased (p = .007) resting time and quadratically affected (p = .033) rumination time. The inclusion of fNDF in the diets provided favorable conditions for ruminal function, digestibility and feeding behavior in goats fed diets containing cactus pear.  相似文献   
25.
Soybean rust in Brazil is currently controlled with several commercial fungicide premixes composed of demethylation inhibitors (EPOXiconazole, CYPRoconazole, PROThioconazole, TEBUconazole), quinone-outside inhibitors (AZOXystrobin, TriFLoXystrobin, PYRAclostrobin, PICOxystrobin), and succinate demethylation inhibitors (BENZovindiflupyr, BIXaFen, FLUXapyroxad). Here, we summarize the performance of eight premixes evaluated in 177 cooperative trials conducted in 46 locations across 10 states from 2015 to 2020. All fungicide treatments were sprayed three times starting at R1/R2. Percentage control (, %), from back-transforming meta-analytic estimates of the log of the ratio, ranged from 56.2% (PICO + CYPR) to 76.8% (BIXF + TFLX + PROT). Estimates of mean yield difference (, kg/ha) between fungicide-treated and untreated plots were greatest for BIXF + TFLX + PROT (1,080) followed by PICO + BENZ (1,010), PYRA + EPOX + FLUX (981.5), AZOX + BENZ (910), TFLX + PROT (891), PICO +TEBU (682), TFLX + CYPR (646), and PICO + CYPR (600). Significant declines in both and in as little as 4 years were detected for AZOX + BENZ (35.3%; 550 kg/ha) and PICO + BENZ (15.5%; 359.8 kg/ha). Variance in was reduced by the inclusion of baseline severity as covariate. In trials where baseline disease was ≥70%, yield was 250 kg/ha greater compared to areas with low baseline disease. Disease control and yield response were generally greater in the south-east, where the frequency of profitable scenarios was 30% higher on average than in the north-west. Results of this meta-analysis are critical for supporting decisions during planning of fungicide programmes.  相似文献   
26.
Four natural products were isolated from the fungus Botryosphaeria rhodina, and their effects on photosynthesis were tested. Only lasiodiplodin (1) inhibited ATP synthesis and electron flow from water to methylviologen; therefore, it acts as a Hill reaction inhibitor in freshly lysed spinach thylakoids. Photosystem I and II and partial reactions as well as ATPase were measured in the presence of 1. Three new different sites of 1 interaction and inhibition were found: one at CF1, the second in the water-splitting enzyme, and the third at the electron-transfer path between P680 and QA; these targets are different from that of the synthetic herbicides present. Electron transport chain inhibition by 1 was corroborated by fluorescence induction kinetics studies.  相似文献   
27.
28.
Two rapid tests evaluated in dogs considered to be of high risk of infection with the Chagas parasite Trypanosoma cruzi using two immunochromatographic assays: Trypanosoma Detect™ for canine, InBios, Seattle, WA and CHAGAS STAT-PAK™ assay, Chembio Diagnostic Systems, Medford, NY, in south central Louisiana. For this purpose a serological survey was carried out in a total of 122 dogs and a serum bank was created. These 122 animals were first tested by IFAT that was used as the standard test. From the serum bank 50 samples were tested using the two rapid Chagas assays and results compared to the standard test IFAT. The serological survey using IFAT showed a prevalence of T. cruzi infection in 22.1% of the tested dogs. In the immunochromatographic assays, 13 and 11 animals were positive on rapid assay: Trypanosoma Detect™ for canine, InBios and CHAGAS STAT-PAK™, Chembio Diagnostic Systems, respectively compared to 11 positive by IFAT. These two immunochromatographic tests have shown high susceptibility and specificity compared to our standard method IFAT. The rapid, easy and accurate screening assays used in conjunction with confirmatory tests, would be an excellent tool for veterinarians to diagnose T. cruzi infection. Early detection of T. cruzi infection may prevent complications through an effective treatment. Greater awareness by veterinarians of the risk, clinical findings, history along with diagnostic methods will contribute greatly to an understanding of the true prevalence of Chagas disease in dogs in Louisiana.  相似文献   
29.
Precocious lines of Eimeria acervulina "Cu" and "I" strains were obtained after 25 passages of oocysts in chickens that showed a shortening of the prepatent period for first oocyst output from 96 h to 81 and 82 h, respectively. Both precocious lines were evaluated for pathogenicity using as criteria weight gain, lesion score and total oocyst production. Infection of the "Cu" precocious line in chickens showed a high weight gain, low lesion score and low oocyst production, when compared to parent strain infected chickens. However, the results did not show a significant difference in relation to the criteria used above for the E. acervulina "I" precocious line when compared to its parent strain. This suggests a low degree of attenuation for the "I" strain but good attenuation for the precocious "Cu" line. The histopathological observations of chickens infected with the E. acervulina "Cu" parent strain and precocious line, comparing life cycle and intestinal lesions, showed: (1) parasite stages only in the border cells of infected chicken intestinal villi, for the precocious line; (2) parasite stages in the border cells of the intestinal villi and submucosa cells near the Lieberkühn glands of the intestine; and (3) high degree of inflammatory cells around the parasites in chickens infected with the parent strain. The "Cu" strain was also characterized for sensitivity against eight anticoccidial drugs. Sensitivity was observed for four anticoccidial drugs and partial resistance for four other drugs, although the strain had never had previous contact with anticoccidial drugs, suggesting the presence of a natural resistance factor. This Brazilian E. acervulina "Cu" precocious line showed attenuation for pathogenicity in chickens, suggesting that it could be a suitable strain for use as a live vaccine in Brazil.  相似文献   
30.
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