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   32篇
  免费   0篇
农学   2篇
  2篇
农作物   1篇
水产渔业   6篇
畜牧兽医   12篇
植物保护   9篇
  2012年   1篇
  2011年   3篇
  2010年   4篇
  2009年   4篇
  2008年   2篇
  2007年   1篇
  2005年   1篇
  2004年   1篇
  1997年   3篇
  1995年   1篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1981年   1篇
  1979年   1篇
  1978年   1篇
排序方式: 共有32条查询结果,搜索用时 15 毫秒
21.
Objective — The purpose of this study was to determine the surgical guidelines for and the survivability of an axial pattern flap based on the superficial temporal artery in cats.
Study Design — The mean survival length and mean percentage area of survival of flaps after 7 days in control and experimental groups, are assessed and compared.
Animals — Ten mature, domestic shorthair cats.
Methods — The superficial temporal artery and vein were incorporated in the flaps of the experimental group (n = 5) and were ligated in the control group (n = 5). Seven days postoperatively, the length of tissue that remained viable in each flap was determined by measurement of the length of the grossly devitalized tissue and subtracting this from total flap length. Results — Mean width and length of all flaps was 2.0 ± 7.0 cm, respectively. Mean survival length (±SD) of experimental and control flaps was 6.9 (0.2) cm and 4.4 (2.2) cm, respectively. Necrosis occurred in all control flaps, resulting in a mean percentage area of survival of 62.8 (11.7)%, compared with 98.6 (3.2)% for experimental flaps. Results were significantly different (P <.05) between the experimental and control groups.
Conclusions — A flap based on the superficial temporal artery may be a source of skin for reconstructive procedures of the maxillofacial region in cats.
Clinical Relevance — Knowledge of the anatomic landmarks and survivability of an axial pattern flap are essential considerations when planning a reconstructive technique.  相似文献   
22.
ABSTRACT Unemployment rates appear to vary widely at a subregional (e.g., local or provincial) level. Using spatial econometric models for spatial autocorrelation, this paper focuses attention on the spatial structure of regional unemployment disparities of Italian provinces. On the basis of findings from the economic literature and of the available socio‐economic data, various model specifications, including different explanatory variables, are tested to investigate the geographical distribution of unemployment in the 103 provinces of Italy for the years 1998 and 2003. The results suggest that there is a clear explanation of unemployment differentials in terms of spatial equilibrium and disequilibrium factors and a significant degree of spatial dependence among labour markets at the provincial level in Italy. Provinces marked by high unemployment, as well as those characterised by low unemployment, tend to be spatially clustered, demonstrating the presence of unemployment “persistency” in space and time regimes.  相似文献   
23.
Objective — The purpose of this report was to determine the efficacy of the application of ventral pins and polymethylmethacrylate for the management of congenital and traumatic atlantoaxial instability (AAI) in dogs.
Study Design — Medical records and radiographs of nine dogs with AAI were reviewed for neurological deficits, clinical diagnosis, surgical technique, and long-term outcome.
Sample Population — Six toy breed dogs with congenital AAI and three medium or large breed dogs with traumatic AAI were identified for inclusion in the study.
Methods — The atlantoaxial joints of nine dogs with AAI were surgically stabilized using ventral application of pins and polymethylmethacrylate. Follow-up evaluation for resolution of clinical signs and possible complications of surgery was performed in all dogs. The median follow-up time for surviving dogs (8) was 11.5 months with a mean of 13 months.
Results — An excellent outcome was identified in five patients. Three dogs had a good outcome and one dog died of respiratory complications. Cervical pain was eliminated or significantly reduced in all dogs that survived and none of the dogs had major residual neurological deficits.
Conclusions — Arthrodesis could not be confirmed on follow-up radiographs due to the presence of the polymethylmethacrylate; however, adequate stabilization of C1-C2 appears to have been achieved based on the resolution of clinical signs.
Clinical Relevance — Application of ventral pins and polymethylmethacrylate is an effective means of surgical treatment for congenital and traumatic AAI.  相似文献   
24.
There is a general perception among Cambodian rice (Oryza sativa) farmers that, after harvesting, rice crop residues that are incorporated into the field benefit the growth of the subsequent rice crop. However, the effect of this action upon weed establishment and growth has not yet been considered. A series of pot and field trials were conducted to determine whether such action could inhibit weed establishment and/or growth. The pot studies first evaluated the response of the test plant (rice line ST‐3) and three weed species, barnyardgrass (Echinochloa crus‐galli), small umbrella sedge (Cyperus difformis), and water primrose (Ludwigia octovalves), to the residue of 16 rice lines and the field trials were later conducted to evaluate the response of the same test plants to the residue of seven putatively allelopathic rice lines and one non‐allelopathic rice line. The residue of all the studied rice lines, depending on how long they had been incorporated into the soil, reduced the establishment and growth of all three weed species, as well as the rice crop. However, if the residue's incorporation was delayed by 2 weeks or only a proportion of the residue was incorporated, the rice crop could withstand the growth‐inhibiting effect, while the inhibition of the establishment and growth of the three weed species was retained. These responses of rice and the weeds to rice crop residues might provide a basis for a weed management strategy, particularly in the resource‐poor rice‐production systems of Cambodia.  相似文献   
25.
An Andalusian Stallion with left hind limb lameness had a radiolucent lesion in the medullary cavity of distal tibial metaphysis. After euthanasia for other disease, the tibia was examined with magnetic resonance (MR). The MR imaging sequences were characterized by a double line sign, although showing quite different lesion area intensities. Histologically, the lesion was compatible with medullary infarction being characterized by normal spongy bone, areas of abundant fibrous tissue and numerous necrotic adipocytes in various stages of destruction.  相似文献   
26.
In this study the spatial distribution of eggs, larvae and juveniles of European anchovy (Engraulis encrasicolus) was followed in 2004 and 2005 during three consecutive cruises each year in spring–summer to test what the limits of retention are in a non‐upwelling area. Eggs, small larvae and large juveniles were mainly distributed over the shelf, whereas large larvae and small juveniles were found mainly off the shelf. Although overall distributions were similar, the 2 yr differed in that there was more of a coastal distribution of individuals in 2004, whereas in 2005 more individuals were found off the shelf. There were no significant differences in the length–weight relationships for individuals found on and off the shelf or between years. The correspondence in circulation patterns and the lack of difference in the length–weight relationships suggest that a single population is present, larvae drifting off the shelf due to currents and returning as mobile juveniles. Quantile regression analysis of the long‐term recruitment index suggests that transport off the shelf may favour good recruitments. This would suggest that in non‐upwelling regions the retention area resulting in good recruitment may not be restricted to the shelf.  相似文献   
27.
Dose-response curves were established for the herbicides chlorsulfuron, metsulfuron-methyl, ethametsulfuron-methyl, imazamethabenz and glyphosate. The plant species were Daucus carota L. and Triticum aestivum L. in cell culture assays, and D. carota L., T. aestivum L., Stellariamedia L., Chenopodium album L. and Avena sativa L., in whole plant assays. Potency ranking of herbicides were similar in the two assays. Low doses of herbicide stimulated growth in both assays, but stimulation was greater in cell cultures. Image processing measured growth in cell cultures and was more sensitive to small differences in responses than manual counts of cell colonies. Dose-response curves had the same shape in both assays, but cell cultures were more sensitive than were whole plants. Comparaison d'essais biologiques d'herbicides effectués sur cultures de cellules et sur plantes entiéres Des courbes dose-effet ont étéétablies pour les herbicides metsulfuron-methyl, ethametsulfuron-methyl, imazamethabenz et glyphosate. Les espèces végétales étaient Daucus carota L. et Triticum aestivum L. en cultures de cellules, et D. carota L., T. aestivum L., Stellaria media L., Chenopodium album L. et Avena sativa L. dans les essais sur plantes entières. Le classement d'efficacité des herbicides était le meme dans les deux types d'essais. Les faibles doses d'herbicides stimulaient la croissance dans les deux essais mais la stimulation était plus importante en cultures de cellules. La mesure par analyse d'image de la croissance des cultures de cellules était plus sensible à de faibles différences que le comptage manuel des colonies. Les courbes dose-effet avaient la meme forme dans les deux essais mais les cultures de cellules étaient plus sensibles que les plantes entières. Vergleich von Herbizid-Biotests mit Zellkulturen und ganzen Pflanzen Fur die Herbizide Chlorsulfuron, Metsulfuronmethyl, Ethametsulfuron-methyl, Imazamethabenz und Glyphosat wurden Dosis/Wirkungs-Kurven erstellt. Die in den Zellkulturen verwendeten Pflanzenarten waren Daucus carota L. und Triticum aestivum L., und bei den Tests mit ganzen Pflanzen D. carota L., T. aestivum L., Stellaria media L., Chenopodium album L. und Avena sativa L. Die Reihenfolge der Herbizide hinsichtlich ihrer Wirksankeit war in beiden Tests ahnlich. Niedrige Herbiziddosen steigerten in beiden Tests das Wachstum, in den Zellkulturen jedoch deutlicher. Bei den Zellkulturen war die Bildanalyse-Messung fur das Erkennen geringer Unterschiede empfindlicher als das Auszahlen der Zellkolonien. Die Dosis/Wirkungs-Kurven hatten fur beide Testmethoden den gleichen Verlauf, aber auch hier erwiesen sich die Zellkulturen empfindlicher als die ganzen Pflanzen.  相似文献   
28.
A necrotic leaf spot of Brazil wood trees is reported as caused by Pestalotiopsis maculans. This appears to be the first report of such a disease.  相似文献   
29.
A series of field experiments was conducted during 1999 and 2000 to study the effect of six Cambodian rice lines that had been selected for their allelopathic potential on the growth of three weed species (barnyardgrass, small umbrella sedge, and water primrose). The results from 2 years' study demonstrate that powerful weed‐establishment and growth‐suppressive mechanisms were present in all of the rice lines tested. This mechanism was equally active on all three weed species studied. Across all the rice lines and across all the weed species, weed establishment was reduced by 71%, the final plant height was reduced by 49%, and the dry biomass was reduced by 80%. A tentative comparison between the effects of the Cambodian rice lines and those of previously characterized allelopathic and non‐allelopathic rice lines revealed that approximately three‐quarters of the weed growth suppression in the Cambodian lines could be attributed to resource competition and one‐quarter could be attributed to allelopathy, although this analysis did not take into account morphological differences between the two types of rice. Such weed growth‐suppressing activity could be particularly useful in subsistence farming systems where the use of selective herbicides is prohibitive or when organic rice production is the objective. The use of rice lines that suppress the growth of weeds is likely to be a potent supplement to present weed management practises and will reduce production costs and the potential for environmental pollution, as well as alleviate some of the social constraints that are associated with labor‐intensive manual weeding.  相似文献   
30.
An Urban Approach to Firm Entry: The Effect of Urban Size   总被引:1,自引:0,他引:1  
ABSTRACT This article explores the determinants of firm entry in Spanish municipalities. The authors consider that size is an important determinant of a city's capacity to attract new manufacturing firms. Panel data were used to estimate the determinants of entry according to urban size in Spain (from 1994 to 1702). This article contributes to the literature on market entry because most previous contributions have focused on regional factors rather than urban ones. The results show that local characteristics affect the formation of new firms. However, more local data are needed to obtain more specific results.  相似文献   
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