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   106篇
  免费   7篇
林业   11篇
基础科学   1篇
  18篇
综合类   36篇
农作物   15篇
水产渔业   2篇
畜牧兽医   26篇
园艺   2篇
植物保护   2篇
  2015年   4篇
  2014年   2篇
  2013年   7篇
  2011年   6篇
  2010年   2篇
  2008年   2篇
  2007年   3篇
  2006年   3篇
  2005年   5篇
  2004年   1篇
  2003年   6篇
  2002年   5篇
  2001年   1篇
  2000年   3篇
  1999年   2篇
  1998年   2篇
  1996年   1篇
  1995年   3篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1984年   3篇
  1983年   1篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
  1975年   2篇
  1973年   1篇
  1972年   2篇
  1969年   2篇
  1968年   1篇
  1966年   1篇
  1965年   1篇
  1957年   2篇
  1955年   1篇
  1948年   1篇
  1947年   3篇
  1945年   1篇
  1944年   2篇
  1943年   3篇
  1941年   1篇
  1940年   1篇
  1938年   1篇
  1919年   1篇
  1903年   1篇
  1902年   1篇
  1893年   2篇
排序方式: 共有113条查询结果,搜索用时 31 毫秒
91.
BackgroundAcute hepatopathy secondary to administration of zonisamide has been reported in 2 dogs, but overall incidence of hepatopathy is unknown.ObjectiveTo characterize the incidence of hepatopathy in dogs administered zonisamide PO.AnimalsThree hundred eighty‐four dogs administered zonisamide PO.MethodsMulticenter retrospective study. Medical records were searched for dogs prescribed zonisamide PO and which had follow‐up for at least 3 months (acute exposure) and >3 months (chronic exposure). Reported clinical signs, physical examination findings, and serum biochemical panels were reviewed for possible hepatotoxicosis. Serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activity and albumin concentration were documented for all available cases.ResultsAcute clinical hepatopathy was found in 2 of 384 treated dogs (0.52%, 95% confidence interval [CI], 0.06‐1.9) after 13‐16 days of zonisamide treatment. One additional dog had elevated serum ALT activity with no clinical signs. Of these 3 dogs, 2 recovered after administration of zonisamide was stopped, and 1 was euthanized because of liver failure. Of the 117 cases chronically administered zonisamide, 10 had an increase in ALP, 6 had an increase in ALT, and 1 had hypoalbuminemia. No clinical signs of liver disease were noted in dogs chronically treated with zonisamide (median, 20 months; range, 5‐94 months).Conclusions and Clinical ImportanceAcute, potentially life‐threatening hepatopathy associated with oral administration of zonisamide to dogs is estimated to occur in less than 1% of dogs and was observed in the first 3 weeks of treatment. Subclinical abnormalities in ALT and ALP activity were noted in <10% of dogs during chronic administration of zonisamide, with no clinical signs of liver disease noted.  相似文献   
92.
93.
The impact of two tillage systems, plow tillage (PT) and no-tillage (NT), on microbial activity and the fate of pesticides in the 0–5 cm soil layer were studied. The insecticides carbofuran and diazinon, and the herbicides atrazine and metolachlor were used in the study, which included the incubation and leaching of pesticides from untreated soils and soils in which microorganisms had been inhibited. The mineralization of ring14C labeled pesticides was studied. The study differentiated between biotic and abiotic processes that determine the fate of pesticides in the soil. Higher leaching rates of pesticides from PT soils are explaned by the relative importance of each of these processes. In NT soils, higher microbial populations and activity were associated with higher mineralization rates of atrazine, diazinon and carbofuran. Enhanced transformation rates played an important role in minimizing the leaching of metolachlor and carbofuran from NT soils. The role of abiotic adsorption/retention was important in minimizing the leaching of metolachlor, carbofuran and atrazine from NT soils. The role of fungi and bacteria in the biodegradation process was studied by selective inhibition techniques. Synergistic effects between fungi and bacteria in the degradation of atrazine and diazinon were observed. Carbofuran was also degraded in the soils where fungi were selectively inhibited. Possible mechanisms for enhanced biodegradation and decreased mobility of these pesticides in the upper layer of NT soils are discussed.  相似文献   
94.
Monthly fluxes of sulphate (SO4 2-) and base cations(Ca2+, Mg2+, K+) were studied from 1993 to 1996 as precipitation passed through forest vegetation and surfacesoil layers in an area receiving low and declining levels of atmospheric sulphate pollution. The canopy was dominated by mature Norway spruce (Picea abies Karsten) and the soilwas a podzol developed on glacial till material. The mean annual bulk deposition of SO4 2- collected in the open was 136 molc ha-1 and that of Ca2+, Mg2+ and K+ was 44, 11 and 25 molc ha-1, respectively. The annual total throughfall deposition of SO4 2- was 318 molc ha-1 and that of Ca2+, Mg2+ and K+ was 151, 64 and 181 molcha-1, respectively. Sulphate was the dominant anion accompanying the base cations leached from the canopy. More than half (58%) of the annual total throughfall deposition ofSO4 2- was retained by the O-horizon and only 15% leached from below the B-horizon. The annual leaching of Ca2+, Mg2+ and K+ from below the B-horizon was14, 25 and 9% of the annual total throughfall deposition, respectively. The transport of base cations through the soil was predominantely countered by SO4 2- anions.  相似文献   
95.
Tickborne diseases (TBDs) such as Lyme disease (LD), babesiosis, ehrlichiosis and Rocky Mountain spotted fever cause substantial morbidity and even mortality in the USA. Data indicate that Hispanic populations may be at greater risk for occupational exposure to ticks and disseminated LD; however, information on knowledge and practices of Hispanic populations regarding TBDs is limited. We surveyed 153 Hispanic and 153 non‐Hispanic residents of Maryland and Virginia to assess awareness of TBDs, prevention practices and risk of tick encounters. Hispanic respondents were less likely than non‐Hispanics to report familiarity with LD symptoms (21% vs. 53%, p < 0.001) and correctly identify ticks as vectors of LD (40% vs. 85%, p < 0.001). Although there was no significant difference in overall proportion of respondents who routinely take one or more preventive measures to prevent tick bites (59% vs. 61%, p = 0.65), Hispanics were more likely to report showering after coming indoors (36% vs. 25%, p = 0.04) but less likely to conduct daily tick checks compared with non‐Hispanics (17% vs. 35%, p < 0.001). History of tick bite or finding a tick crawling on oneself or a household member in the past year did not significantly differ between Hispanics and non‐Hispanics (19% vs. 24%, p = 0.26). Notably, after controlling for Hispanic/non‐Hispanic ethnicity, primary language (English vs. Spanish) was a significant predictor of whether an individual had knowledge of LD symptoms, correctly identified ticks as vectors for LD and performed daily tick checks. These results provide guidance for future development of more targeted and effective TBD prevention education for both Hispanic and non‐Hispanic communities.  相似文献   
96.
97.
98.
99.
100.
Metamaterial electromagnetic cloak at microwave frequencies   总被引:1,自引:0,他引:1  
  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