全文获取类型
收费全文 | 229篇 |
免费 | 37篇 |
专业分类
林业 | 62篇 |
农学 | 2篇 |
2篇 | |
综合类 | 11篇 |
农作物 | 2篇 |
水产渔业 | 1篇 |
畜牧兽医 | 111篇 |
植物保护 | 75篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 18篇 |
2015年 | 11篇 |
2014年 | 11篇 |
2013年 | 14篇 |
2012年 | 2篇 |
2011年 | 12篇 |
2010年 | 6篇 |
2009年 | 10篇 |
2008年 | 7篇 |
2007年 | 10篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
排序方式: 共有266条查询结果,搜索用时 343 毫秒
51.
52.
Variation in growth rates and aggressiveness of naturally occurring self‐fertile and self‐sterile isolates of the wilt pathogen Ceratocystis albifundus
下载免费PDF全文
![点击此处可从《Plant pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ceratocystis albifundus is the most important fungal pathogen of black wattle (Acacia mearnsii) grown in plantations in southern and eastern Africa. It is a homothallic fungus but also undergoes unidirectional mating type switching. As a result, the ascospore progeny can be either self‐fertile or self‐sterile. The only apparent difference between these mating types is the deletion of the MAT1‐2‐1 gene in self‐sterile isolates. There is some evidence suggesting that self‐sterile isolates grow more slowly than self‐fertile isolates, but this has not been tested rigorously. The aim of this study was to determine whether self‐sterile isolates are less fit by examining growth rate, relative germination rate and pathogenicity. Five self‐sterile isolates were generated from each of five self‐fertile isolates of C. albifundus and these 30 isolates were compared. The results showed that the self‐sterile isolates grew consistently slower and were less pathogenic than the self‐fertile isolates. The germination ratio of self‐fertile to self‐sterile isolates from single ascospores collected from the ascomata of five self‐fertile isolates was on average 7:3. This could be a consequence of the self‐sterile isolates having a lower germination rate. This observation, and the lower growth and pathogenicity levels, suggests that self‐sterile isolates are not likely to compete effectively in nature, raising intriguing questions regarding their role and value to C. albifundus and other fungi having a similar mating system. 相似文献
53.
M. L. Vélez M. P. A. Coetzee M. J. Wingfield M. Rajchenberg A. G. Greslebin 《Plant pathology》2014,63(1):212-220
Phytophthora austrocedrae is a recently discovered pathogen that causes severe mortality of Austrocedrus chilensis in Patagonia. The high level of susceptibility of the host tree, together with the distribution pattern of the pathogen, have led to the hypothesis that P. austrocedrae was introduced into Argentina. The aim of this study was to assess the population structure of P. austrocedrae isolates from Argentina in order to gain an understanding of the origin and spread of the pathogen. Genetic diversity was determined based on amplified fragment length polymorphisms (AFLPs). In total, 48 isolates of P. austrocedrae were obtained from infected A. chilensis trees, representing the geographical range of the host. Four primer combinations were used for the AFLP analysis. Of the 332 scored bands, 12% were polymorphic. Gene diversity (h) ranged from 0·01 to 0·03; the Shannon index (I) ranged from 0·01 to 0·04. A high degree of genetic similarity was observed among the isolates (pairwise S values = 0·958–1; 0·993 ± 0·009, mean ± SD). A frequency histogram showed that most of the isolate pairs were identical. Principal coordinate analysis using three‐dimensional plots did not group any of the isolates based on their geographical origin. The low genetic diversity (within and between sites) and absence of population structure linked to geographic origin, together with the aggressiveness of the pathogen and the disease progression pattern, suggest that P. austrocedrae might have been introduced into Argentina. 相似文献
54.
Outcomes of Heimlich valve drainage in dogs 总被引:1,自引:1,他引:0
Objective and design Retrospective study of the outcomes of Heimlich valve drainage in dogs.
Procedure Medical records of the past 3 years were retrospectively reviewed. Heimlich valve drainage was used in 34 dogs (median body weight 30 ± 5 kg): lobectomy (n = 15), pneumonectomy (n = 9), intrathoracic oesophageal surgery (n = 2), diaphragmatic hernia repair (n = 1), traumatic open pneumothorax (n = 2), bilobectomy (n = 2), ligation of the thoracic duct (n = 1), and chylothorax and pneumothorax (n = 1 each). Evacuation of air and/or fluid from the pleural cavity was performed with the Heimlich valve following thoracostomy tube insertion. During drainage, the dogs were closely monitored for possible respiratory failure. Termination of Heimlich valve drainage was controlled with underwater seal drainage and assessed with thoracic radiography.
Results Negative intrathoracic pressure was provided in 29 dogs without any complications. Post pneumonectomy respiratory syncope and post lobectomy massive hemothorax, which did not originate from the Heimlich valve, were the only postoperative complications. Dysfunction of the valve diaphragm, open pneumothorax and intrathoracic localisation of an acute gastric dilatation–volvulus syndrome caused by a left-sided diaphragmatic hernia following pneumonectomy were the Heimlich valve drainage complications.
Conclusions The Heimlich valve can be used as a continuous drainage device in dogs, but the complications reported here should be considered by veterinary practitioners. 相似文献
Procedure Medical records of the past 3 years were retrospectively reviewed. Heimlich valve drainage was used in 34 dogs (median body weight 30 ± 5 kg): lobectomy (n = 15), pneumonectomy (n = 9), intrathoracic oesophageal surgery (n = 2), diaphragmatic hernia repair (n = 1), traumatic open pneumothorax (n = 2), bilobectomy (n = 2), ligation of the thoracic duct (n = 1), and chylothorax and pneumothorax (n = 1 each). Evacuation of air and/or fluid from the pleural cavity was performed with the Heimlich valve following thoracostomy tube insertion. During drainage, the dogs were closely monitored for possible respiratory failure. Termination of Heimlich valve drainage was controlled with underwater seal drainage and assessed with thoracic radiography.
Results Negative intrathoracic pressure was provided in 29 dogs without any complications. Post pneumonectomy respiratory syncope and post lobectomy massive hemothorax, which did not originate from the Heimlich valve, were the only postoperative complications. Dysfunction of the valve diaphragm, open pneumothorax and intrathoracic localisation of an acute gastric dilatation–volvulus syndrome caused by a left-sided diaphragmatic hernia following pneumonectomy were the Heimlich valve drainage complications.
Conclusions The Heimlich valve can be used as a continuous drainage device in dogs, but the complications reported here should be considered by veterinary practitioners. 相似文献
55.
M. Marin O. Preisig B. D. Wingfield T. Kirisits M. J. Wingfield 《Forest Pathology》2009,39(4):249-265
The blue‐stain fungus and vascular stain pathogen Ceratocystis polonica and its associated bark beetle vectors, particularly Ips typographus and I. typographus japonicus, cause significant losses to several spruce species in Eurasia. Nothing is, however, known about the population genetics of this conifer pathogen. In this study, a set of single sequence repeat (SSR) markers were developed to determine the population structure and genetic diversity of C. polonica in Europe and Japan. ISSR‐PCR primers were used to target SSR‐rich regions and specific primers were designed flanking the SSR regions found in these amplicons. The SSR primers developed for C. polonica were found to be transferable to six other Ceratocystis species from conifers, residing in the Ceratocystis coerulescens complex. Ninety‐eight isolates representing four populations of C. polonica (Austria, Norway, Poland and Japan) were tested using 10 selected polymorphic SSR markers. A high level of gene diversity was found in C. polonica as a whole (H = 0.53). Analysis of G statistics showed a low degree of population structure in Europe and a high level of gene flow between populations (Gst = 0.05, Nm = 8.5). In contrast, the Japanese and the European populations of C. polonica displayed strong genetic separation, which is likely caused by geographic isolation. The low level of population structure of C. polonica in Europe and the differentiation between the European and the Japanese fungal populations mirror previous findings for I. typographus and I. typographus japonicus, the main insect vectors of this fungus. These results support the view that the fungus and the insect have closely co‐evolved together. This study also suggests that movement of C. polonica and its vectors between Europe and Asia pose a threat to forestry on both continents and this should clearly be avoided. 相似文献
56.
M. Kvas E. T. Steenkamp A. O. Al Adawi M. L. Deadman A. A. Al Jahwari W. F. O. Marasas B. D. Wingfield R. C. Ploetz M. J. Wingfield 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(2):195-199
Mango malformation, caused by Fusarium mangiferae, represents the most important floral disease of mango. The first symptoms of this disease were noticed in the beginning of
2005 in plantations at Sohar in the Sultanate of Oman. The affected inflorescences were abnormally enlarged and branched with
heavy and dried-out panicles. Based on morphology and DNA-sequence data for the genes encoding translation elongation factor
1α and β-tubulin, the pathogen associated with these symptoms was identified as F. mangiferae. 相似文献
57.
Host specificity of co‐infecting Botryosphaeriaceae on ornamental and forest trees in the Western Balkans
下载免费PDF全文
![点击此处可从《Forest Pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The Botryosphaeriaceae is a diverse family of endophytes and fungal pathogens of mainly woody plants. We considered the host range and distribution of these fungi by sampling diseased ornamental and forest trees and shrubs in Serbia, Montenegro, Bosnia and Herzegovina, spanning a Mediterranean and a Continental climatic region. In total, ten Botryosphaeriaceae species were identified in the Western Balkans and with the exception of Sphaeropsis visci and Phaeobotryon cupressi, which occurred on one host, all the species had a broader host range. Phaeobotryon cupressi was found only in the Mediterranean region and S. visci, Dothiorella sp., Dothiorella sarmentorum and Diplodia seriata were present only in the Continental region. Pathogenicity tests were conducted on a variety of hosts from which the Botryosphaeriaceae species were isolated. These included leaves and/or stems of seedlings of 21 hosts, and cut leaves and/or branches of six hosts. Moreover, stems of seedlings of Chamaecyparis lawsoniana, Cedrus deodara, Picea omorika, Pinus patula and Eucalyptus grandis were inoculated as hosts from which some or all of the Botryosphaeriaceae species used for inoculation were not isolated. Inoculations showed that the majority of these fungi could also co‐infect hosts other than those from which they were isolated. The results suggest that most of the species have broad host ranges and can potentially cause disease on a broad range of tree species under certain conditions. 相似文献
58.
59.
Louwrance P. Wright Andrew J. Davis Brenda D. Wingfield Pedro W. Crous Tim Brenneman Michael J. Wingfield 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(2):199-206
Cylindrocladium parasiticum is an important pathogen of peanut (Arachis hypogaea) causing the disease Cylindrocladium black rot. The genetic structure of this haploid pathogen was determined for populations
associated with peanut in Georgia, USA. Ten polymorphic microsatellite markers were used to determine genetic and genotypic
diversity among three sub-populations representing the geographic distribution of peanut production in Georgia. Among 200
isolates collected, only 10 unique multilocus haplotypes were identified, with one multilocus haplotype occurring 176 times.
Although no evidence for random mating was observed, the existence of loops in a constructed haplotype network hint at the
possibility of recombination events. The absence of random mating might therefore be attributed to the homothallic nature
of C. parasiticum as well as the clonality of the population, without excluding the possible occurrence of recombination. Cylindrocladium parasiticum thus appears to consist of a genetically homogeneous population throughout Georgia with mainly clonal reproduction or inbreeding
contributing to the observed population genetic structure. 相似文献
60.
Dothistroma needle blight: an emerging epidemic caused by Dothistroma septosporum in Colombia
下载免费PDF全文
![点击此处可从《Plant pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Plantation forestry in Colombia is based mainly on non‐native species of Pinus and Eucalyptus. Since 2008, a disease with symptoms similar to those of dothistroma needle blight (DNB) has been found affecting large areas planted to Pinus spp. The aim of this study was to identify the causal pathogen as well as to document the levels of disease incidence and severity. Isolates from each of three forestry zones, collected from different host species, were compared based on rDNA sequence of the ITS regions. These were conclusively identified as Dothistroma septosporum, one of two Dothistroma spp. known to cause DNB. Susceptibility was greatest on low elevation Pinus tecunumanii followed by Pinus kesiya and Pinus oocarpa. Pinus maximinoi and high elevation P. tecunumanii showed tolerance to D. septosporum. The disease incidence in the different zones varied significantly with the North zone being the most severely affected. This constitutes the first report of disease distribution and susceptibility of hosts, as well as the first consideration of the relative importance of D. septosporum in Colombia. 相似文献