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   1132篇
  免费   67篇
林业   48篇
农学   33篇
基础科学   2篇
  143篇
综合类   103篇
农作物   29篇
水产渔业   47篇
畜牧兽医   730篇
园艺   28篇
植物保护   36篇
  2023年   17篇
  2022年   14篇
  2021年   20篇
  2020年   36篇
  2019年   38篇
  2018年   28篇
  2017年   21篇
  2016年   27篇
  2015年   28篇
  2014年   28篇
  2013年   44篇
  2012年   73篇
  2011年   91篇
  2010年   36篇
  2009年   39篇
  2008年   72篇
  2007年   89篇
  2006年   79篇
  2005年   68篇
  2004年   65篇
  2003年   77篇
  2002年   64篇
  2001年   11篇
  2000年   18篇
  1999年   10篇
  1998年   12篇
  1997年   10篇
  1996年   12篇
  1995年   5篇
  1994年   4篇
  1993年   8篇
  1992年   9篇
  1991年   3篇
  1990年   5篇
  1989年   10篇
  1988年   3篇
  1987年   3篇
  1985年   3篇
  1983年   2篇
  1981年   2篇
  1980年   2篇
  1979年   1篇
  1975年   1篇
  1974年   2篇
  1972年   2篇
  1970年   1篇
  1969年   1篇
  1967年   1篇
  1966年   1篇
  1957年   1篇
排序方式: 共有1199条查询结果,搜索用时 31 毫秒
991.
猪链球菌感染常常很复杂 ,因为猪的扁桃体内和鼻腔中存在多种不同的血清型和不同的菌株。必须用与所见临床病例有关的特定菌株进行流行病学研究。用新的分子生物学技术来对同一血清型的不同菌株进行比较 ,必然很快就能使我们更充分地认识这一疾病  相似文献   
992.
Objective: To review the clinical spectrum and mechanisms of action of furosemide in human and small animal veterinary patients. Data sources: Review of human and veterinary literature. Data synthesis: Furosemide is used primarily for its properties as a loop diuretic; however, it has many other actions that may be clinically applicable. Furosemide has a vasodilatory effect that precedes diuresis that may confer its immediate benefit in patients with volume overload. Furosemide can be inhaled to relieve dyspnea in patients with bronchospasm. Furosemide also shows promise as an adjunct to antiseizure therapy to help control epilepsy, status epilepticus, and acute ischemic damage related to seizures. It has activity as an antioxidant, iodine depletive, and may increase thoracic lymph duct flow. Reported furosemide side effects include altered drug metabolism, electrolyte depletion, ototoxicity, mucociliary impairment, endocrine and exocrine pancreatic effects, delayed wound healing, sulfonamide toxicity, and thyroid binding interference. It is worthwhile to consider the implications of these effects when using furosemide either alone or in combination with other drugs. Conclusions: Despite the research in animal models that demonstrates a wide spectrum of pharmacologic activity, furosemide has not been widely recognized or used clinically in veterinary medicine except as a loop diuretic.  相似文献   
993.
ObjectiveTo assess the pharmacokinetics of hydromorphone administered intravenously (IV) or subcutaneously (SC) to dogs.Study designRandomized experimental trial.AnimalsSeven healthy male neutered Beagles aged 12.13 ± 1.2 months and weighing 11.72 ± 1.10 kg.MethodsThe study was a randomized Latin square block design. Dogs were randomly assigned to receive hydromorphone hydrochloride 0.1 mg kg−1 or 0.5 mg kg−1 IV (n = 4 dogs) or 0.1 mg kg−1 (n = 6) or 0.5 mg kg−1 (n = 5) SC on separate occasions with a minimum 14-day washout between experiments. Blood was sampled via a vascular access port at serial intervals after drug administration. Serum was analyzed by mass spectrometry. Pharmacokinetic parameters were determined with computer software.ResultsSerum concentrations of hydromorphone decreased quickly after both routes of administration of either dose. The serum half-life, clearance, and volume of distribution after IV hydromorphone at 0.1 mg kg−1 were 0.57 hours (geometric mean), 106.28 mL minute−1 kg−1, and 5.35 L kg−1, and at 0.5 mg kg−1 were 1.00 hour, 60.30 mL minute−1 kg−1, and 5.23 L kg−1, respectively. The serum half-life after SC hydromorphone at 0.1 mg kg−1 and 0.5 mg kg−1 was 0.66 hours and 1.11 hours, respectively.Conclusions and clinical relevanceHydromorphone has a short half-life, suggesting that frequent dosing intervals are needed. Based on pharmacokinetic parameters calculated in this study, 0.1 mg kg−1 IV or SC q 2 hours or a constant rate infusion of hydromorphone at 0.03 mg kg−1 hour−1 are suggested for future studies to assess the analgesic effect of hydromorphone.  相似文献   
994.
Objective – To examine serum sodium, glucose, and tonicity in cats with diabetic ketosis. Design – Retrospective study. Setting – A university‐based referral hospital. Animals – Cats admitted to the ICU during the period 1998 to 2002 with a diagnosis of diabetic ketosis. Interventions – None. Routine clinical management of diabetes and associated conditions. Measurements – Serum biochemistry assessments. Main Results – Abnormalities of glucose, sodium and serum tonicity (ST) were common in the study group. Serum sodium but not glucose correlated closely with ST. A subset of cats treated with intravenous insulin and an isotonic sodium‐containing solution for 72 hours showed a significant decrease in glucose from admission values at 48 and 72 hours (but not at 24 hours). Serum sodium, potassium, and ST were not significantly different from admission values at any time over the 72‐hour period. However, the relative contribution of individual osmolytes varied over the course of treatment. Although glucose decreased >120% from admission values over the 72‐hour treatment period, the approximately 5% rise in serum sodium that occurred offset the osmotic effect of falling glucose and the overall ST change was <3%. Conclusions – The incidence of osmotic‐mediated neurologic complications during treatment of cats with diabetic ketosis is low in part because the minimal fluctuation in ST during treatment likely prevents the development of osmotic gradients between serum and central nervous system tissues. The use of isotonic sodium‐containing fluids in the treatment of feline diabetes acts to minimize large osmotic shifts by adding sodium to the serum compartment as the glucose concentration falls.  相似文献   
995.
Objective: To describe the case management for a dog diagnosed with a nasopharyngeal polyp.
Case summary: A 9-week-old Shar-Pei puppy presented for progressive dyspnea and collapse. Clinical signs were consistent with an upper airway obstruction (UAO) and a temporary tracheostomy was performed. The puppy was at first diagnosed with and treated for brachycephalic airway syndrome but continued to exhibit signs of an UAO after soft palate resection. Nasopharyngoscopy revealed a nasopharyngeal polyp causing the UAO, which was surgically removed. The puppy has been free of clinical signs for 1 year after removal of the polyp.
New or unique information provided: This is the first report of a nasopharyngeal polyp causing a life-threatening UAO in a puppy. It emphasizes the importance of examining the nasopharyngeal space in neonates presenting with UAO.  相似文献   
996.
Cache Valley virus (CVV) is a mosquito‐borne RNA virus detected throughout North America, Central America and parts of South America. A limited number of human case reports have described severe illness. CVV infection has been associated with outbreaks of congenital defects in small ruminants in Canada and the United States. A scoping review was conducted to identify, characterize and summarize research on CVV, and to identify research gaps. A structured search was conducted in eight electronic databases, with additional search verification and grey literature investigation. All captured studies were independently appraised by two reviewers for relevance and data characterization. The review captured 143 relevant studies investigating CVV epidemiology (n = 104), pathogenesis (n = 37), viral characteristics (n = 24), transmission (n = 14), diagnostic test performance (n = 8) and mitigation strategies (n = 2). Evidence of CVV infection was found in mosquito studies (n = 47), and serological evidence of exposure was demonstrated in animals (n = 41), as well as human (n = 20) studies. In sheep, five outbreaks of birth defects following asymptomatic dam CVV infection during the first 50 days of pregnancy were reported. Only six human cases of CVV‐associated illness were captured, with case symptoms described as initially non‐specific, progressing to more severe clinical signs (e.g., meningitis). No research was identified investigating treatment, societal knowledge and risk perception, economic burden or predictive models related to the impact of climate change on CVV. CVV circulates in mosquito and animal species across a large area of the Americas. Small ruminants are the only animals in which CVV‐associated clinical disease has been extensively studied. It is likely that human cases are under‐reported or misdiagnosed. Future research should focus on the impact of CVV infection in human and animal populations.  相似文献   
997.
998.
999.
A 1‐year, 8‐month‐old Rhodesian Ridgeback was presented with obtundation, ambulatory tetraparesis, and myoclonus. Initial clinical findings included ionized hypercalcemia with an apparent marked increase in parathyroid hormone, thrombocytopenia, and nonregenerative anemia. Low numbers of circulating atypical cells were noted on blood film evaluation. Brain magnetic resonance imaging identified an extra‐axial contrast enhancing subtentorial lesion, and cerebrospinal fluid (CSF) analysis documented a marked atypical lymphocytic pleocytosis. Flow cytometry performed on the CSF demonstrated expression of only CD45, CD90, and MHC class II, with Pax5 positivity on subsequent immunohistochemistry. The final diagnosis was of B‐cell lymphoblastic lymphoma or acute leukemia, given the distribution of disease and the presence of significant bone marrow infiltration alongside an aggressive clinical course. The unusual immunophenotype of the neoplastic cells and hypercalcemia presented antemortem diagnostic challenges, highlighting the need for a multidisciplinary approach and caution in the interpretation of clinical abnormalities in cases with multiple comorbidities.  相似文献   
1000.
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