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   151篇
  免费   5篇
林业   3篇
农学   6篇
基础科学   6篇
  16篇
综合类   6篇
农作物   2篇
水产渔业   5篇
畜牧兽医   96篇
园艺   3篇
植物保护   13篇
  2023年   1篇
  2021年   3篇
  2020年   1篇
  2019年   7篇
  2018年   2篇
  2017年   1篇
  2015年   5篇
  2013年   5篇
  2012年   9篇
  2011年   23篇
  2010年   5篇
  2009年   7篇
  2008年   13篇
  2007年   13篇
  2006年   11篇
  2005年   14篇
  2004年   6篇
  2003年   6篇
  2002年   4篇
  2001年   1篇
  2000年   5篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1991年   2篇
  1990年   1篇
排序方式: 共有156条查询结果,搜索用时 31 毫秒
51.
The chemical composition of marabou(Dichrostachys cinerea) wood and its treatment with acetic acid were investigated.Two different treatment approaches,direct acetosolv and combined acid prehydrolysis/acetosolv,were evaluated.The effects of acetic acid concentration(50%,70% and 90%) and temperature(normal boiling temperature and 121°C) on yield of solids,solubilization of lignin and hemicelluloses and recovery of cellulose were evaluated for both treatments.High solubilization of marabou components was observed in the direct acetosolv treatment at 121°C,especially at the highest acetic acid concentration,where around 84.8% of lignin and 78% of hemicelluloses were removed.When the material was subjected to acid prehydrolysis prior to acetosolv treatment,lignin solubilization was improved,especially at low acetic acid concentrations.Above 80% of the solubilized lignin was recovered from the liquors in the direct acetosolv treatment,but the recovery was lower in the combined treatment.Cellulose was well preserved in all the treatment schemes.  相似文献   
52.
Bovine leukemia virus (BLV) is among the most widespread livestock pathogens in many countries. Despite advances in understanding the pathogenesis of this disease, little is known about the involvement of oxidative stress. Therefore, this study examined the antioxidant status and the markers of oxidative stress in BLV-infected dairy cows. BLV infection was associated with an increase in triacylglycerol levels, a decrease in glutathione peroxidase (GSH-Px) activity and a tendency toward lower superoxide dismutase activity in the infected animals. No significant difference was observed in other markers of oxidative stress (i.e., conjugated dienes, hydroperoxides and malondialdehyde) in the infected animals compared to controls. A novel method for the analysis of oxidative stress, Z-scan based on the measurement of the mean-value of θ in low density lipoprotein indicated that the infected animals had low-density lipoprotein particles that were slightly less modified than those from the healthy group. Thus, we conclude that BLV infection is associated with a selective decrease in GSH-Px activity without any alteration in the common plasma markers of oxidative stress.  相似文献   
53.
A 3 yr old male English setter dog was presented for evaluation of a 6-wk history of intermittent diarrhea. After standard gastroduodenoscopy and colonoscopy showed normal mucosa, double-balloon endoscopy (DBE) was used via both oral and anal approaches. Gross changes consistent with inflammation in the jejunum were seen, and biopsy specimens were obtained. Histologic analysis confirmed a diagnosis of lymphocytic-plasmacytic jejunitis. Clinical remission of the disease occurred after 3 mo of therapy with prednisone, metronidazole, and a novel protein diet. Use of DBE has not been previously reported in dogs with inflammatory bowel disease, and isolated lymphocytic-plasmacytic jejunitis has not been described. The described cases of intestinal inflammatory disease diagnosed by conventional endoscopy were related to pathologic changes in the duodenum, ileum or colon, but not the jejunum. The main advantage of the DBE technique allowed examination of portions of the small intestine (jejunum) that were not commonly accessible by standard endoscopic techniques, and permitted a minimally invasive collection of biopsy samples compared with surgical biopsy. This case highlights the need to consider using DBE in animals with gastrointestinal disorders, whose symptoms are not readily explained by routine tests, conventional endoscopy, and dietary or therapeutic trials.  相似文献   
54.
PRACTICAL RELEVANCE: Neurological disease is a relatively common reason for referral, constituting approximately 10% of the feline referral caseload. Nearly one-third to one-half of these cases may be infectious in origin. As such, an awareness of infectious diseases causing central nervous system (CNS) signs in cats, and their clinical diagnosis and management, is relevant to anyone dealing with cats on a regular basis. GLOBAL IMPORTANCE: Some conditions (eg, rabies) are more common in certain countries than others. Conditions such as feline infectious peritonitis (FIP) and toxoplasmosis are of global significance. PATIENT GROUP: Many infectious diseases may affect any feline population. Some, such as FIP, are more common in pedigree households, whereas others such as toxoplasmosis, feline immunodeficiency virus (FIV) or feline leukaemia virus (FeLV) infections, are more likely to affect a single cat with an outdoor lifestyle. EQUIPMENT: All patients benefit from thorough history taking and clinical, neurological and ophthalmic examinations, which all require minimal equipment. Infectious diseases may often be diagnosed on blood samples; however, definitive diagnosis may require more extensive investigation involving cerebrospinal fluid analysis or advanced imaging necessitating access to computed tomography or magnetic resonance imaging. EVIDENCE BASE: The information in this review, which summarises current knowledge of infectious diseases affecting the CNS, is collated from publications on the infectious diseases comprising previous research papers, review articles, case series, case reports and textbooks, supplemented by the clinical experience of the authors.  相似文献   
55.
Skull hyperostosis is a frequently recognised feature of meningioma in feline and human patients, occurring at a frequency of around 4.5% of human cases. Evidence of osteolysis with extension of meningioma into, and in some cases through, the region of skull hyperostosis is much less commonly described in human patients. Here we present a 12-year-old cat with marked skull hyperostosis secondary to an intracranial meningioma, with magnetic resonance imaging and computed tomography evidence of tumour extension into the skull, centrally within the region of hyperostosis. Only a thin layer of bone was remaining between the mass and the extracranial region. Surgical resection of the region of skull demonstrating tumour invasion and the underlying mass resulted in good resolution of clinical signs and no post-surgical recurrence of meningioma within the 5 months follow-up period. Histopathological examination confirmed the mass to be fibroblastic meningioma.  相似文献   
56.
Hypertension in Cats With Chronic Renal Failure or Hyperthyroidism   总被引:6,自引:0,他引:6  
The Doppler ultrasonic recording technique was used to measure systolic and diastolic blood pressures indirectly in 28 cats with naturally occurring renal failure, 39 cats with hyperthyroidism, and 33 clinically normal cats. The mean systolic and diastolic blood pressures in the normal cats were 118.4 +/- 10.6 mm Hg and 83.8 +/- 12.2 mm Hg, respectively. In the cats with chronic renal failure, both the systolic (146.6 +/- 25.4 mm Hg) and diastolic (96.6 +/- 15.2 mm Hg) blood pressures were significantly higher (P less than 0.0001 and P less than 0.01, respectively) than in the normal cats. Elevations in systolic and/or diastolic blood pressure were recorded in 17 (61%) of the 28 cats with chronic renal failure. In the 39 untreated hyperthyroid cats, both the mean systolic (167.9 +/- 28.9 mm Hg) and diastolic (111.6 +/- 21.5 mm Hg) pressures also were significantly higher (P less than 0.0001) than normal. Increased systolic and/or diastolic blood pressure was recorded in 34 (87%) of the 39 hyperthyroid cats. In seven cats with hyperthyroidism that were reevaluated two to four months after successful treatment of the hyperthyroid state, there was a significant fall in mean systolic pressure (P less than 0.05) from a pretreatment value of 159.5 +/- 15.4 mm Hg to a posttreatment value of 132.0 +/- 1.62 mm Hg. Overall, the results of this study indicate that mild to moderate hypertension is common in cats with chronic renal failure and in cats with untreated hyperthyroidism. In addition, the hypertension appears to be reversible following successful treatment of the hyperthyroid state.  相似文献   
57.
Faecal samples from 111 cats with diarrhoea that were living in the UK were submitted for the assessment of Tritrichomonas foetus infection by polymerase chain reaction (PCR). Sixteen (14.4%) samples were found to be positive. In agreement with studies from the USA, infected cats were predominantly of a year of age or less and of a pedigree breed, with Siamese and Bengal cats specifically over-represented in this population.  相似文献   
58.
59.
60.
Blood samples were collected from 41 cats presented for pre-anaesthetic assessments, routine geriatric screening, or re-assessment of ongoing chronic medical disorders. Samples were either left to clot or anticoagulated with lithium heparin, then assessed for their potassium concentration within 1h of collection, and again after remaining in contact with their cell pellet for 48 h. There was a significantly higher potassium concentration in the serum samples compared to the plasma samples, both in the basal and 48-h samples (although this difference was most marked in the basal samples). Ageing of both serum and plasma samples also resulted in an increase in the potassium concentration when compared with the basal values for each sample type. The mean difference (basal serum minus basal plasma) in potassium concentration was 0.47 mmol/l. While it is probable that the potassium came from either leukocytes and/or thrombocytes the mean total leukocyte count and the mean thrombocyte count were below the upper limit of the reference intervals for our laboratory and the rise in the potassium level did not appear to be directly related to either of these values.  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