全文获取类型
收费全文 | 716篇 |
免费 | 42篇 |
专业分类
林业 | 31篇 |
农学 | 11篇 |
基础科学 | 6篇 |
77篇 | |
综合类 | 120篇 |
农作物 | 36篇 |
水产渔业 | 62篇 |
畜牧兽医 | 380篇 |
园艺 | 8篇 |
植物保护 | 27篇 |
出版年
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2016年 | 18篇 |
2015年 | 9篇 |
2014年 | 16篇 |
2013年 | 26篇 |
2012年 | 21篇 |
2011年 | 41篇 |
2010年 | 25篇 |
2009年 | 22篇 |
2008年 | 29篇 |
2007年 | 28篇 |
2006年 | 39篇 |
2005年 | 33篇 |
2004年 | 33篇 |
2003年 | 39篇 |
2002年 | 44篇 |
2001年 | 26篇 |
2000年 | 24篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1997年 | 15篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1992年 | 14篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1975年 | 4篇 |
1973年 | 5篇 |
1970年 | 6篇 |
1969年 | 3篇 |
1968年 | 4篇 |
1967年 | 6篇 |
1966年 | 3篇 |
1965年 | 3篇 |
1941年 | 3篇 |
排序方式: 共有758条查询结果,搜索用时 31 毫秒
31.
In vitro elution of gentamicin, amikacin, and ceftiofur from polymethylmethacrylate and hydroxyapatite cement 总被引:3,自引:0,他引:3
Ethell MT Bennett RA Brown MP Merritt K Davidson JS Tran T 《Veterinary surgery : VS》2000,29(5):375-382
OBJECTIVE: To compare the elution characteristics of ceftiofur and liquid and powdered gentamicin and amikacin from polymethylmethacrylate (PMMA) and from hydroxyapatite cement (HAC). METHODS: PMMA and HAC beads in triplicate were impregnated with various amounts and formulations of antibiotics. Beads were immersed in 5 mL of phosphate buffered saline that was replaced at 1, 3, 6, and 12 hours, and 1, 2, 3, 5, 7, 10, 14, 18, 22, 26, and 30 days. The eluent was stored at -70 degrees C until assayed within 2 weeks by microbiological assay (gentamicin and amikacin) or capillary electrophoresis (ceftiofur). RESULTS: Rate of elution for all beads was greatest within the first 24 hours. Cumulative release of total antibiotic dose from beads over 30 days was significantly greater from HAC than PMMA. Antibiotic elution was directly related to the amount of antibiotic incorporated into the cement. Powdered and liquid forms of gentamicin had similar elution rates from PMMA. Elution of amikacin from PMMA beads was greater when the powdered form was used compared with liquid amikacin. Eluent concentrations of ceftiofur were similar to those of the aminoglycosides during the first 3 to 7 days but then decreased precipitously by comparison. CONCLUSIONS: Elution of antibiotics from HAC was greater than from PMMA. Gentamicin- and amikacin-impregnated PMMA and HAC released bactericidal concentrations of antibiotic for at least 30 days. Ceftiofur-impregnated PMMA or HAC is unlikely to provide long-term bactericidal concentrations. CLINICAL RELEVANCE: Gentamicin and amikacin elute effectively from PMMA and HAC. 相似文献
32.
An 11-year-old American Quarterhorse gelding presented for moderate periorbital swelling and exophthalmia of the left eye. The menace response, and direct and consensual pupillary light reflexes were absent in the left eye. Conjunctival hyperemia, blepharedema, a mydriatic pupil, resistance to retropulsion, and an increased intraocular pressure were present. A soft-tissue mass could be palpated in the left retrobulbar space by pressing onto the orbit over the supraorbital fossa. Incomplete surgical resection of the mass was performed and histopathologic evaluation was consistent with a fibroma. Normal pupillary light reflexes and vision returned following surgery. The mass has not recurred 14 months after surgery. 相似文献
33.
34.
Jennifer Anne Davidson Rohan B. E. Kimber 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):99-110
Ascochyta blight causes significant yield loss in pulse crops worldwide. Integrated disease management is essential to take
advantage of cultivars with partial resistance to this disease. The most effective practices, established by decades of research,
use a combination of disease-free seed, destruction or avoidance of inoculum sources, manipulation of sowing dates, seed and
foliar fungicides, and cultivars with improved resistance. An understanding of the pathosystems and the inter-relationship
between host, pathogen and the environment is essential to be able to make correct decisions for disease control without compromising
the agronomic or economic ideal. For individual pathosystems, some components of the integrated management principles may
need to be given greater consideration than others. For instance, destruction of infested residue may be incompatible with
no or minimum tillage practices, or rotation intervals may need to be extended in environments that slow the speed of residue
decomposition. For ascochyta-susceptible chickpeas the use of disease-free seed, or seed treatments, is crucial as seed-borne
infection is highly effective as primary inoculum and epidemics develop rapidly from foci in favourable conditions. Implemented
fungicide strategies differ according to cultivar resistance and the control efficacy of fungicides, and the effectiveness
of genetic resistance varies according to seasonal conditions. Studies are being undertaken to develop advanced decision support
tools to assist growers in making more informed decisions regarding fungicide and agronomic practices for disease control. 相似文献
35.
Feline ocular toxoplasmosis 总被引:2,自引:0,他引:2
Ocular infection with Toxoplasma gondii is a well-recognized and important clinical entity in many animal species. In the cat, ocular toxoplasmosis is commonly associated with systemic infection, yet its role in causing anterior uveitis in an otherwise healthy cat is unclear. The purpose of this article is to review the salient epidemiological, clinical, and histopathologic features of systemic and ocular toxoplasmosis in the cat. Additionally, pathogenesis and possible immunopathogenic mechanisms of ocular toxoplasmosis, which may account for the higher prevalence of anterior uveitis in cats seropositive for T. gondii , are discussed. Finally, diagnosis, treatment and prevention of feline toxoplasmosis are reviewed. 相似文献
36.
37.
38.
Physiological Responses of Rainbow Trout Oncorhynchus mykiss to Crowding and Anesthesia with AQUI-S™
Glen W. Davidson Peter S. Davie Graham Young Reece T. Fowler 《Journal of the World Aquaculture Society》2000,31(1):105-114
Abstract.— Following exposure to the anesthetic AQUI-S™, plasma cortisol concentration in immature rainbow trout was measured as (mean) 293 ± 48 ng/ mL, which was significantly ( P > 0.05) higher than the mean concentration in resting fish. Cortisol concentrations remained significantly ( P > 0.05) elevated for at least 24 h after treatment. This was accompanied by a significant increase and decrease in hematocrit and plasma potassium, respectively. These perturbations continued for at least 48 h following recovery from anesthesia. Plasma concentrations of total protein and sodium remained unchanged following anesthesia with AQUI-S™. Crowding stress is commonly encountered by fish during manipulation in aquaculture situations. Anesthetising fish prior to, and during, manipulation may reduce the associated stress. Changes in cortisol values resulting from crowding (30 min; 0.1 kg/L) during anesthesia with AQUI-S™ were not appreciably different from those in fish crowded without anesthesia. Thus, anesthesia with AQUI-S™ at the recommended dose of 17 mg/L did not appear to be effective for alleviating the stress of crowding under the conditions of our experiments. 相似文献
39.
40.
加拿大安达略省家禽生产者对死禽处理通常有以下几种方法:选择经认证的死畜禽处理公司,坑埋,焚烧,堆肥.本文描述了使用堆肥法成功堆肥家禽屠体的一些关键因素. 堆肥是一个狭长的可被生物降解的有机物质堆,有很大的表面积以便氧气良好地渗透.堆肥通过需氧微生物分解生物有机物质制成一个稳定的、类似土壤的物质,称为腐殖质.为了刺激微生物快速降解,有必要给这些生长增殖的微生物提供最理想的环境. 相似文献