全文获取类型
收费全文 | 1113篇 |
免费 | 109篇 |
专业分类
林业 | 55篇 |
农学 | 24篇 |
基础科学 | 1篇 |
207篇 | |
综合类 | 86篇 |
农作物 | 54篇 |
水产渔业 | 50篇 |
畜牧兽医 | 603篇 |
园艺 | 32篇 |
植物保护 | 110篇 |
出版年
2023年 | 12篇 |
2022年 | 10篇 |
2021年 | 37篇 |
2020年 | 27篇 |
2019年 | 45篇 |
2018年 | 28篇 |
2017年 | 30篇 |
2016年 | 24篇 |
2015年 | 26篇 |
2014年 | 41篇 |
2013年 | 50篇 |
2012年 | 79篇 |
2011年 | 88篇 |
2010年 | 44篇 |
2009年 | 44篇 |
2008年 | 85篇 |
2007年 | 76篇 |
2006年 | 62篇 |
2005年 | 57篇 |
2004年 | 56篇 |
2003年 | 43篇 |
2002年 | 50篇 |
2001年 | 14篇 |
2000年 | 8篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 9篇 |
1993年 | 5篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1967年 | 6篇 |
1966年 | 4篇 |
1964年 | 3篇 |
1963年 | 4篇 |
1962年 | 5篇 |
1961年 | 5篇 |
1960年 | 8篇 |
1959年 | 7篇 |
1958年 | 5篇 |
1955年 | 8篇 |
1932年 | 4篇 |
排序方式: 共有1222条查询结果,搜索用时 0 毫秒
11.
12.
Carrie A. Davis Reza Seddighi Sherry K. Cox Xiaocun Sun Christine M. Egger Thomas J. Doherty 《Veterinary anaesthesia and analgesia》2017,44(4):727-737
Objective
To determine the effect of fentanyl on the induction dose of propofol and minimum infusion rate required to prevent movement in response to noxious stimulation (MIRNM) in dogs.Study design
Crossover experimental design.Animals
Six healthy, adult intact male Beagle dogs, mean ± standard deviation 12.6 ± 0.4 kg.Methods
Dogs were administered 0.9% saline (treatment P), fentanyl (5 μg kg?1) (treatment PLDF) or fentanyl (10 μg kg?1) (treatment PHDF) intravenously over 5 minutes. Five minutes later, anesthesia was induced with propofol (2 mg kg?1, followed by 1 mg kg?1 every 15 seconds to achieve intubation) and maintained for 90 minutes by constant rate infusions (CRIs) of propofol alone or with fentanyl: P, propofol (0.5 mg kg?1 minute?1); PLDF, propofol (0.35 mg kg?1 minute?1) and fentanyl (0.1 μg kg?1 minute?1); PHDF, propofol (0.3 mg kg?1 minute?1) and fentanyl (0.2 μg kg?1 minute?1). Propofol CRI was increased or decreased based on the response to stimulation (50 V, 50 Hz, 10 mA), with 20 minutes between adjustments. Data were analyzed using a mixed-model anova and presented as mean ± standard error.Results
ropofol induction doses were 6.16 ± 0.31, 3.67 ± 0.21 and 3.33 ± 0.42 mg kg?1 for P, PLDF and PHDF, respectively. Doses for PLDF and PHDF were significantly decreased from P (p < 0.05) but not different between treatments. Propofol MIRNM was 0.60 ± 0.04, 0.29 ± 0.02 and 0.22 ± 0.02 mg kg?1 minute?1 for P, PLDF and PHDF, respectively. MIRNM in PLDF and PHDF was significantly decreased from P. MIRNM in PLDF and PHDF were not different, but their respective percent decreases of 51 ± 3 and 63 ± 2% differed (p = 0.035).Conclusions and clinical relevance
Fentanyl, at the doses studied, caused statistically significant and clinically important decreases in the propofol induction dose and MIRNM. 相似文献13.
Differentiation between dogs with thrombosis and normal dogs using the overall hemostasis potential assay 下载免费PDF全文
Anna L. Dengate BVSc BMedSc Marie‐Christine Morel‐Kopp PhD Julia A. Beatty PhD BVetMed BSc Vanessa Barrs BVSc MVetClinStud Jody A. Braddock BVSc MVetClinStud Richard K. Churcher BVSc Bethany J. Wilson BVSc PhD Christopher M. Ward BMedSc MBChB PhD 《Journal of Veterinary Emergency and Critical Care》2016,26(3):446-452
14.
Comparative evaluation of six different body regions of the dog using analog and digital radiography
Meyer-Lindenberg A Ebermaier C Wolvekamp P Tellhelm B Meutstege FJ Lang J Hartung K Fehr M Nolte I 《Berliner und Münchener tier?rztliche Wochenschrift》2008,121(5-6):216-227
In this study the quality of digital and analog radiography in dogs was compared. For this purpose, three conventional radiographs (varying in exposure) and three digital radiographs (varying in MUSI-contrast [MUSI = MUlti Scale Image Contrast], the main post-processing parameter) of six different body regions of the dog were evaluated (thorax, abdomen, skull, femur, hip joints, elbow). The quality of the radiographs was evaluated by eight veterinary specialists familiar with radiographic images using a questionnaire based on details of each body region significant in obtaining a radiographic diagnosis. In the first part of the study the overall quality of the radiographs was evaluated. Within one region, 89.5% (43/48) chose a digital radiograph as the best image. Divided into analog and digital groups, the digital image with the highest MUSI-contrast was most often considered the best, while the analog image considered the best varied between the one with the medium and the one with the longest exposure time. In the second part of the study, each image was rated for the visibility of specific, diagnostically important details. After summarisation of the scores for each criterion, divided into analog and digital imaging, the digital images were rated considerably superior to conventional images. The results of image comparison revealed that digital radiographs showed better image detail than radiographs taken with the analog technique in all six areas of the body. 相似文献
15.
Heather Bixler Christine Ellis 《Veterinary Clinics of North America: Exotic Animal Practice》2004,7(2):227-55, v
Convivial and playful, the ferret has cohabited with humans for hundreds of years. Maintenance of this mustelid's health and quality of life is paramount for the endurance of the human-animal bond. This review article for veterinary care givers, veterinarians, and staff, encompasses discussions on: husbandry, clinical techniques, prevalent diseases, history taking, physical examination, vaccination, and pain recognition. This article also enables the veterinary community to contribute to the care and welfare of ferret patients by offering facts to distinguish these animals from dogs and cats. 相似文献
16.
BACKGROUND: The potential of systemic neonicotinoid insecticides to control potato leafhopper, Empoasca fabae (Harris), a damaging pest of wine grapes in the eastern United States, was investigated. Soil or foliar applications were made to potted or field‐grown vines, and the response of leafhoppers was determined in clip cages over the following month on young or mature leaves. RESULTS: Foliar application of imidacloprid caused immediate and long‐lasting reductions in E. fabae survival on both leaf ages, whereas the activity of soil‐applied imidacloprid was delayed. Clothianidin, imidacloprid and thiamethoxam all provided long‐lasting reduction in leafhopper survival on young and mature foliage when applied through either delivery route. However, the percentage of moribund nymphs was significantly greater on foliar‐treated vines and increased over time in mature and immature leaves compared with soil‐treated vines. Residue analysis of foliar‐applied imidacloprid showed an 89% decline in mature leaves from day 1 to day 27, and a 98% decline in immature leaves over the same time period. Comparison of soil‐applied clothianidin, imidacloprid and thiamethoxam in field‐grown vines showed significant reduction in E. fabae only on mature leaves of vines treated with thiamethoxam. CONCLUSIONS: Neonicotinoids can control E. fabae in small vines, even in rapidly expanding foliage where this pest causes greatest injury. Soil application provides superior long‐term vine protection because declining residues on foliar‐treated vines lead to suboptimal activity within 2–3 weeks. Vineyard managers of susceptible cultivars may take advantage of this approach to E. fabae management by using foliar applications of the three neonicotinoids tested here, or by using soil‐applied thiamethoxam. Copyright © 2011 Society of Chemical Industry 相似文献
17.
Kreuder C Miller MA Lowenstine LJ Conrad PA Carpenter TE Jessup DA Mazet JA 《American journal of veterinary research》2005,66(2):289-299
OBJECTIVE: To describe cardiac lesions and identify risk factors associated with myocarditis and dilated cardiomyopathy (DCM) in beach-cast southern sea otters. ANIMALS: Free-ranging southern sea otters. PROCEDURE: Sea otters were necropsied at the Marine Wildlife Veterinary Care and Research Center from 1998 through 2001. Microscopic and gross necropsy findings were used to classify sea otters as myocarditis or DCM case otters or control otters. Univariate, multivariate, and spatial analytical techniques were used to evaluate associations among myocarditis; DCM; common sea otter pathogens; and potential infectious, toxic, and nutritional causes. RESULTS: Clusters of sea otters with myocarditis and DCM were identified in the southern aspect of the sea otter range from May to November 2000. Risk factors for myocarditis included age, good body condition, and exposure to domoic acid and Sarcocystis neurona. Myocarditis associated with domoic acid occurred predominantly in the southern part of the range, whereas myocarditis associated with S. neurona occurred in the northern part of the range. Age and suspected previous exposure to domoic acid were identified as major risk factors for DCM. A sample of otters with DCM had significantly lower concentrations of myocardial L-carnitine than control and myocarditis case otters. CONCLUSIONS AND CLINICAL RELEVANCE: Cardiac disease is an important cause of death in southern sea otters. Domoic acid toxicosis and infection with S. neurona are likely to be 2 important causes of myocarditis in sea otters. Domoic acid-induced myocarditis appears to progress to DCM, and depletion of myocardial L-carnitine may play a key role in this pathogenesis. 相似文献
18.
Clayton T Larue Michael Goley Lei Shi Artem G Evdokimov Oscar C Sparks Christine Ellis Andrew M Wollacott Timothy J Rydel Coralie E Halls Brook Van Scoyoc Xiaoran Fu Jeffrey R Nageotte Adewale M Adio Meiying Zheng Eric J Sturman Graeme S Garvey Marguerite J Varagona 《Pest management science》2019,75(8):2086-2094
19.
Parker JE Timm KI Smith BB Van Saun RJ Winters KM Sukon P Snow CM 《American journal of veterinary research》2002,63(7):948-953
OBJECTIVE: To evaluate temporal changes in bone mineral density associated with seasonal variation in serum vitamin D, calcium, and phosphorus concentrations in alpacas. ANIMALS: 5 healthy mature neutered male alpacas. PROCEDURE: Metacarpal bone mineral density was measured at 4 times during a year. Each time alpacas were weighed, blood was collected for determination of serum calcium, phosphorus, and vitamin D concentrations, and samples of feed were analyzed for nutrient content. Vitamin D status was determined by use of an assay that measured serum 25-hydroxycalciferol concentration. Effects of changes in serum vitamin D, calcium, and phosphorus concentration and body weight with season on bone mineral density were determined. RESULTS: Bone mineral density, body weight, and serum vitamin D and phosphorus concentrations varied with season. Bone mineral density, serum vitamin D concentration, and body weight also varied among individual alpacas. Serum vitamin D concentration was lower in January than the previous October and increased from May to the following September. The decrease in bone mineral density lagged behind the decrease in serum vitamin D concentration and was lower in May, compared with the previous October. Body weight was lower in May than the previous October or following September. Solar radiation was highest in July and lowest in December. CONCLUSIONS AND CLINICAL RELEVANCE: Seasonal changes in bone mineral density are associated with changes in serum vitamin D concentrations in alpacas. Changes in bone mineral density associated with a decline in serum vitamin D concentration may predispose some alpacas to developing fractures minimal trauma. 相似文献
20.