全文获取类型
收费全文 | 290篇 |
免费 | 48篇 |
专业分类
林业 | 39篇 |
农学 | 3篇 |
基础科学 | 1篇 |
22篇 | |
综合类 | 38篇 |
农作物 | 6篇 |
水产渔业 | 20篇 |
畜牧兽医 | 177篇 |
园艺 | 4篇 |
植物保护 | 28篇 |
出版年
2023年 | 3篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 19篇 |
2017年 | 9篇 |
2016年 | 19篇 |
2015年 | 10篇 |
2014年 | 18篇 |
2013年 | 27篇 |
2012年 | 11篇 |
2011年 | 22篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 10篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1988年 | 9篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1962年 | 1篇 |
1955年 | 1篇 |
1943年 | 1篇 |
1929年 | 1篇 |
1927年 | 1篇 |
1926年 | 3篇 |
1924年 | 1篇 |
1916年 | 1篇 |
1914年 | 1篇 |
1909年 | 2篇 |
1900年 | 1篇 |
1883年 | 1篇 |
排序方式: 共有338条查询结果,搜索用时 31 毫秒
11.
12.
Lasiodiplodia theobromae is a cosmopolitan fungus with a worldwide distribution in the tropics and subtropics, where it causes shoot blight and dieback of trees and shrubs and imparts blue stain in timber. In this study, eight simple sequence repeat (SSR) markers were used to evaluate the genetic diversity and gene flow between populations of L. theobromae. The relationships between isolates from different hosts were considered using three populations from different tree species in Venezuela (VEN) and the relationships between isolates from different geographical origins included populations from VEN, South Africa (RSA) and Mexico (MEX). A small number of predominant genotypes were encountered in the VEN and RSA populations and thus genotypic diversity was low. There was no evidence of host specificity for isolates of L. theobromae and there was very high gene flow between populations from different hosts. Geographical isolation existed between populations of the pathogen from different regions, with unique alleles fixed in the different populations. Gene flow was, however, less restricted between isolates from MEX and the other populations, consistent with MEX as a common source of seed in both VEN and RSA. Genetic analysis suggested predominantly clonal reproduction with some genotypes widely distributed within a region. The broad host range of L. theobromae and the lack of evidence for host specialization, coupled with its endophytic nature and the common appearance of symptoms only after harvest, is likely to hinder disease management strategies. 相似文献
13.
Omega‐3 Fatty Acid Supplementation Provides an Additional Benefit to a Low‐Dust Diet in the Management of Horses with Chronic Lower Airway Inflammatory Disease 下载免费PDF全文
N. Nogradi L.L. Couetil J. Messick M.A. Stochelski J.R. Burgess 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(1):299-306
Background
Omega‐3 polyunsaturated fatty acid (PUFA) may benefit humans and animals with chronic inflammatory diseases.Hypothesis
Omega‐3 PUFA supplementation improves clinical signs, lung function, and airway inflammation in horses with recurrent airway obstruction (RAO) and inflammatory airway disease (IAD).Animals
Eight research horses and 35 client‐owned horses.Methods
A pilot study examined the dose of PUFA that can alter plasma PUFA composition. Then, a randomized, controlled clinical trial was performed in horses with RAO and IAD. Horses were fed a complete pelleted diet with no hay and randomly assigned to 1 of 3 daily treatments for 2 months: 30 or 60 g of the supplement or 30 g of placebo. Clinical signs, lung function, plasma PUFA composition, and bronchoalveolar lavage fluid (BALF) cytology were evaluated. Data were expressed as median (25–75th percentiles). P < .05 was considered significant.Results
Polyunsaturated fatty acid supplementation resulted in increased plasma docosahexaenoic acid (DHA) that peaked at 4 weeks. Clinical improvement was noted in all horses involved in the clinical trial, but the group that received PUFA had greater improvement in clinical signs (cough score improved 60%), lung function (respiratory effort decreased 48%), and BALF (neutrophils decreased from 23 to 9%) when compared to placebo (cough score improved 33%, respiratory effort decreased 27%, BALF neutrophils increased from 11 to 17%; P < .05).Conclusions and Clinical Importance
Feeding horses with RAO and IAD a PUFA supplement containing 1.5–3 g DHA for 2 months provides an additional benefit to low‐dust diet. 相似文献14.
Agroforestry Systems - Globally, forest ecosystems are shrinking and their health is declining due to a range of biotic and abiotic factors. Forest ecosystems in Pakistan... 相似文献
15.
16.
17.
PE Sbardella RR Ulguim DL Fontana CV Ferrari ML Bernardi I Wentz FP Bortolozzo 《Reproduction in domestic animals》2014,49(1):59-64
The study evaluated the reproductive performance of primiparous sows submitted to post‐cervical insemination (PCAI) compared with cervical artificial insemination (CAI). Difficulty with catheter introduction, the occurrence of bleeding or semen backflow during insemination, and volume and sperm cell backflow up to 60 min after insemination were also evaluated. Sows were homogenously distributed, according to body weight loss in lactation, lactation length, weaned piglets, weaning‐to‐oestrus interval and total born in previous farrowing, in two treatments: PCAI (n = 165) with 1.5 × 109 sperm cells in 45 ml (2.4 ± 0.04 doses per sow) and CAI (n = 165) with 3 × 109 sperm cells in 90 ml (2.5 ± 0.04 doses per sow). During PCAI, sows were inseminated in the absence of boars. Transabdominal real‐time ultrasonography was performed at oestrus onset, immediately before the first insemination and at 24 h after last insemination. There was no difference (P > 0.05) between treatments in farrowing rate (91.5% × 89.1%) and litter size (12.5 × 11.9 piglets born, respectively for PCAI and CAI sows). Successful passage of the intrauterine catheter in all the inseminations was possible in 86.8% (165/190) of sows initially allocated to PCAI treatment. Difficulty of introducing the catheter in at least one insemination did not affect the reproductive performance of PCAI sows (P > 0.05). Bleeding during insemination did not affect (P > 0.05) the farrowing rate in both treatments, but litter size was reduced in CAI and PCAI sows (P ≤ 0.06). Percentage of spermatozoa present in backflow within 1 h after insemination was greater in CAI than PCAI sows (P < 0.01). More than 85% of primiparous sows can be successfully post‐cervical inseminated with doses containing 1.5 × 109 sperm cells in the absence of the boar during insemination without impairing the reproductive performance. 相似文献
18.
R. M. Wallace D. Stanek S. Griese D. Krulak N. M. Vora L. Pacha V. Kan M. Said C. Williams T. H. Burgess S. S. Clausen C. Austin J. Gabel M. Lehman L. N. Finelli G. Selvaggi P. Joyce F. Gordin D. Benator A. Bettano S. Cersovsky C. Blackmore S. V. Jones B. D. Buchanan A. I. Fernandez D. Dinelli K. Agnes A. Clark J. Gill M. Irmler D. Blythe K. Mitchell T. J. Whitman M. J. Zapor S. Zorich C. Witkop P. Jenkins P. Mora D. Droller S. Turner L. Dunn P. Williams C. Richards G. Ewing K. Chapman C. Corbitt T. Girimont R. Franka S. Recuenco J. D. Blanton K. A. Feldman 《Zoonoses and public health》2014,61(8):560-570
This article describes and contrasts the public health response to two human rabies cases: one organ recipient diagnosed within days of symptom onset and the transplant donor who was diagnosed 18 months post‐symptom onset. In response to an organ‐transplant‐related rabies case diagnosed in 2013, organ donor and recipient investigations were conducted by multiple public health agencies. Persons with potential exposure to infectious patient materials were assessed for rabies virus exposure. An exposure investigation was conducted to determine the source of the organ donor's infection. Over 100 persons from more than 20 agencies spent over 2700 h conducting contact investigations in healthcare, military and community settings. The 564 persons assessed include 417 healthcare workers [5.8% recommended for post‐exposure prophylaxis (PEP)], 96 community contacts (15.6% recommended for PEP), 30 autopsy personnel (50% recommended for PEP), and 21 other persons (4.8% recommended for PEP). Donor contacts represented 188 assessed with 20.2% recommended for PEP, compared with 5.6% of 306 recipient contacts recommended for PEP. Human rabies cases result in substantial use of public health and medical resources, especially when diagnosis is delayed. Although rare, clinicians should consider rabies in cases of encephalitis of unexplained aetiology, particularly for cases that may result in organ donation. 相似文献
19.
Stephen George David Burgess Michael Leaver Nick Frerichs 《Fish physiology and biochemistry》1992,10(1):43-54
Intraperitoneal injection of turbot with Cd induced the synthesis of a low molecular weight hepatic Cd-binding protein and a 500bp mRNA, which hybridised to a plaice metallothionein (MT) cRNA probe. The Cd-binding protein displayed cross-reactivity in a competitive ELISA with antiserum raised against rainbow trout MT and had the characteristic amino acid composition, metal stoichiometry and spectral characteristics of a Class I MT. Only one isoform was apparent on ion exchange chromatography. Southern blot analysis of DNA cleaved with four restriction enzymes suggested that only a single MT gene is present in turbot.In an established turbot fibroblast cell line, Cd induced MT mRNA and MT levels in a dose and time-dependent manner. MT was also induced by Cu, Hg and Zn but not Pb exposure. Physiological concentrations of glucocorticoids and sex hormones did not induce MT synthesis, although at high concentrations a positive response to corticosterone, dexamethasone, hydrocortisone or progesterone was observedin vitro indicating the possible presence of a functional steroid regulatory element in the fish MT gene.Abbreviations used AMP
adenosine monophosphate
- CHSE
chinook salmon embryo
- DMSO
dimethyl sulphoxide
- HPLC
high performance liquid chromatography
- KB
kenacid blue
- MT
metallothionein
- Mr
molecular weight (kDaltons)
- NR
neutral red
- PEG
polyethylene glycol
- RTH
rainbow trout hepatoma
- SDS
sodium dodecyl sulphate
- SSC
0.15M NaCl, 0.015M sodium citrate
- TF
turbot fibroblast 相似文献
20.
P. Crisp I. R. Crute R. A. Sutherland S. M. Angell K. Bloor H. Burgess P. L. Gordon 《Euphytica》1989,42(3):215-226
Summary About 1000 Brassica oleracea accessions were evaluated in glasshouse tests for response to Plasmodiophora brassicae (clubroot). Resistance was confirmed in some north and west European kales and cabbage. A new source of resistance in cabbage, from Eire, is reported. Most other accessions were highly susceptible but lower levels of susceptibility were observed in open pollinated Brussels sprouts and forms of south European cabbage, cauliflower and broccoli. Modern breeding (as in the production of hybrid cultivars) appears to have resulted in increased susceptibility in several crop types. The implications of these results for the exploitation of germplasm are discussed. 相似文献