全文获取类型
收费全文 | 387篇 |
免费 | 20篇 |
专业分类
林业 | 25篇 |
农学 | 11篇 |
93篇 | |
综合类 | 50篇 |
农作物 | 25篇 |
水产渔业 | 37篇 |
畜牧兽医 | 128篇 |
园艺 | 13篇 |
植物保护 | 25篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 21篇 |
2019年 | 16篇 |
2018年 | 10篇 |
2017年 | 17篇 |
2016年 | 27篇 |
2015年 | 16篇 |
2014年 | 14篇 |
2013年 | 11篇 |
2012年 | 34篇 |
2011年 | 42篇 |
2010年 | 15篇 |
2009年 | 20篇 |
2008年 | 18篇 |
2007年 | 24篇 |
2006年 | 16篇 |
2005年 | 16篇 |
2004年 | 22篇 |
2003年 | 10篇 |
2002年 | 16篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有407条查询结果,搜索用时 15 毫秒
91.
Lipid droplet distribution of immature canine oocytes in relation to their size and the reproductive stage 下载免费PDF全文
Federica Ariu Alessandro Strina Ombretta Murrone Laura Falchi Daniela Bebbere Sergio Ledda Maria Teresa Zedda Salvatore Pau Luisa Bogliolo 《Animal Science Journal》2016,87(1):147-150
This study investigated the distribution of lipid droplets (LD) in immature canine oocytes in relation to their size and the reproductive stage. Oocytes were collected from the ovaries of bitches at different estrous stages, divided according to their size (110‐120 µm; >120 µm), and stained with Nile Red to detect lipid droplet distribution. At the follicular phase most of the oocytes displayed a diffuse pattern of LD distribution, whereas at anestrus and luteal phase oocytes showed LD mainly in a peripheral/ perinuclear LD distribution. A significantly higher intensity of LD has been recorded in the oocytes > 120 µm compared to those of smaller size (110 ‐ 120 µm) at all stages of the estrous cycle. At follicular phase, oocytes > 120 µm displayed LD intensity similar to that of oocytes > 120 µm at luteal phase and higher compared to the oocytes of the other groups. 相似文献
92.
Artificial inoculation with fungal species involved in the Petri disease was performed on in vitro grapevine shoots. After 2 months, plantlets were observed and the presence of any leaf chlorosis or necrosis, considered as symptoms of the disease, were recorded. The fungal inoculation caused an increase in the number of symptomatic in vitro plants and in the incidence of external symptoms. Recovery of the fungal species was obtained after incubation of excised tissue fragments from the inoculated in vitro plants while some fertile fragments were collected also from plants without external symptoms. Higher levels of symptoms were observed in the rootstock varieties inoculated with Phaeomoniella chlamydospora while the lowest incidence was observed in the Aglianico cultivar. The possibility to correlate the visual assessment of in vitro plants with the data obtained by the analysis of digital images was confirmed. 相似文献
93.
Alessandro Cristalli Matteo Morini Arianna Comin Katia Capello Kyaw Sunn Marco Martini 《Tropical animal health and production》2018,50(2):251-257
Highly pathogenic avian influenza virus subtype H5N1 first entered Myanmar in 2006 in the Mandalay District. Several H5N1 outbreaks followed and the one of Bago East District (2007) required post outbreak surveillance in the at-risk domestic duck population of the Moyingyi Wetland. A field epidemiological study based on a randomised prospective stratified study with five surveys provided the serological evidence that the avian influenza H5 subtype circulates in the domestic duck population and spreads to almost all the newly housed (and negative) flocks in the time span of a seasonal production cycle. Virological investigation was negative. The survival analysis showed that the probability of seroconversion increased rapidly over the study period, without significant difference among different agro-ecosystems. The analysis suggests that viral spread in the new cycle could be limited if control measures were adopted at the time new flocks are housed. The study recommends that future surveillance schemes for ducks are designed in a way to get as much information as possible from serological results which should drive virological sampling to determined farms. 相似文献
94.
95.
Renato Levi-Minzi Alessandro Saviozzi Roberto Cardelli Riccardo Riffaldi 《Archives of Agronomy and Soil Science》2013,59(3):279-288
Fourteen agricultural soils from various areas of Tuscany were characterized by a range of measurements indicative of soil biological activity. The objective of our research was to identify soil parameters suitable as indicators for evaluating their quality. In general, enzyme activities were found to vary widely, with the highest activity for each enzyme being distributed among only five of the 14 soils studied. The narrowest range (14-fold) in enzyme activities for the various soils was observed for catalase and the widest range (577-fold) for g -glucosidase. Biomass C and, among the measured enzyme activities, amylase, were well correlated with total organic carbon, total N, cation and anion exchange capacity. Positive correlations were found between the maximum water holding capacity and dehydrogenase, amylase, biomass C, FDA hydrolytic activity, the biological index of fertility and the enzyme activity number, so showing that soil moisture may play an important role in affecting soil biological characteristics. No significant correlations were observed among the soil enzymes themselves. The FDA hydrolytic activity appeared to be the index most related with the other biological characteristics tested in this study and, for this reason, can be considered the most effective index for putting in evidence relationships existing between the different biological characteristics in the soils investigated. 相似文献
96.
Matteo Alessandro Saladini Laura Asteggiano Marco Giuseppe Pansa Luca Giordani Luca Serre Graziano Vittone 《国际虫害防治杂志》2016,62(3):214-221
The European earwig, Forficula auricularia L. (Dermaptera: Forficulidae), is a well-known species that is cosmopolitan and present throughout Europe. Due to its omnivorous feeding behaviour, this species can act as a generalist predator, preying on several top fruit pests, but also as a pest causing shallow gouges or holes in stone and soft fruits such as apricots, strawberries, raspberries or blackberries. In Piedmont (NW Italy), significant fruit damage has been observed lately in apricot orchards where earwigs fed on ripening fruits and made a considerable part of the produce unmarketable. In this study, we sampled earwig populations in three apricot orchards in Piedmont and tested the effectiveness of glue barriers applied to the tree trunks in reducing both earwig density in the canopy and fruit damage. The arboreal glues Rampastop® and Vebicolla® were tested both in the field and laboratory trials. Glue barriers demonstrated to be effective control measures, significantly reducing earwig abundance in the canopy and fruit damage. Rampastop® gave better results on old trees with a very rough and cracked bark, since in that case Vebicolla® could not perfectly bond with the trunk. 相似文献
97.
Borgarelli M Santilli RA Chiavegato D D'Agnolo G Zanatta R Mannelli A Tarducci A 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2006,20(1):104-110
The purpose of this study was to investigate the prognostic value of various clinical, ECG, echocardiographic, and Doppler echocardiographic variables in dogs with dilated cardiomyopathy. The relationship to survival of 11 variables was evaluated in 63 dogs. Studied variables were age at time of diagnosis, class of heart failure (HF), dyspnea, ascites, atrial fibrillation (AF), ejection fraction (EF), E-point septal separation, end-diastolic volume index, end-systolic volume index (ESV-I), and restrictive or nonrestrictive transmitral flow (TMF) pattern. Median survival time was 671 days (lower 95% confidence limit, 350 days). Survival curves showed that severity of HF, ascites, ESV-I greater than 140 mL/m2, EF less than 25%, and restrictive TMF pattern had a significant negative relation to survival time. Thirty-nine dogs with both sinus rhythm and AF presented adequate TMF recordings; in these dogs, after stratification by TMF pattern, the restrictive TMF pattern was the most important negative prognostic indicator. We conclude that in dogs with dilated cardiomyopathy the restrictive TMF pattern appears to represent a useful prognostic indicator. Class of HF, ascites, ESV-I, and EF are also useful indexes if an adequate TMF pattern is not recorded. 相似文献
98.
Connectivity providers for semi-aquatic vertebrates: the case of the endangered otter in Italy 总被引:1,自引:0,他引:1
Maria Laura Carranza Evelina D’Alessandro Santiago Saura Anna Loy 《Landscape Ecology》2012,27(2):281-290
Modeling habitat connectivity for conservation of semi-aquatic vertebrates is a particularly challenging task, due to the
fine-scale and linear distribution of riverine habitats and to the capacity of species to move both on freshwater and terrestrial
realms. We showed how the integrated analytical framework provided by the habitat availability (reachability) metrics and
their fractions can be used to effectively evaluate the distinctive roles and contributions of both habitat patches (aquatic
and riparian) and linkage areas (permeable land matrix) to the connectivity and functioning of a complex system composed of
multiple river catchments. Analysis focused on the Eurasian otter (Lutra lutra L.), one of the most endangered mammals in Italy. We developed a network connectivity model based on suitable otter habitats
and multiple least-cost paths between catchments. A graph analytical approach was used to identify critical nodes and links
for the potential expansion and long-term viability of the species in the region. Our results showed that few basins concentrate
most of the importance for sustaining the overall habitat connectivity, due to the extension of suitable habitats they contain,
their strong connections with other basins, and their importance as stepping stones that uphold ecological fluxes between
otherwise weakly connected habitats. The potential contribution of each basin to enhance the dispersal and expansion of otters
in the area strongly depended on the key functional paths (sequences of links and nodes) among the catchments. We identified
vacant basins that could be colonized by otters in the near future, and connecting areas in the intermediate matrix that might
be preferentially used to conduct and promote dispersal movements and gene flow in the area. The novel approach here adopted
could be easily extended to other semiaquatic species and catchment systems, offering a management strategy to preserve the
hydrographic network as an integrated system, as well as a joint evaluation of the role of both the river courses and the
matrix in between in a single landscape model. 相似文献
99.
Bienboire-Frosini C Cozzi A Lafont-Lecuelle C Vervloet D Ronin C Pageat P 《Veterinary journal (London, England : 1997)》2012,193(1):162-167
The biological function of Fel d 1, the major cat allergen released in the environment, is still unclear despite studies suggesting a putative role in chemical communication. Structural and immunological polymorphisms of Fel d 1 have been described. This study examined how Fel d 1 immunological polymorphism may have a physiological origin by estimating a potential relationship with the sex of cats and cat-human interactions. Samples from bath washes of 21 cats were screened to study antibody binding to Fel d 1 using an ELISA. Personality and Tolerance Handling scores were used to assess the behaviour of the cats. In the washes, Fel d 1 concentrations were significantly lower in females than in males (P<0.05). Slopes from the ELISA dose-dependent curves varied among the cats: males secreted Fel d 1 variants with higher antibody recognition than females (P<0.01). Females that were aggressive and difficult to handle displayed a diminished slope value, and therefore a weaker Fel d 1 immunoreactivity in global washes, compared to females that were sociable (P=0.09) and easy to handle (P=0.07). This study shows a variable immunological polymorphism of Fel d 1 within a cat population, particularly between males and females, and this polymorphism appears to be related to cat-human interactions. 相似文献
100.
Dario D'Ovidio Giacomo Rossi Raffaele Melidone Francesca Menna Alessandro Fioretti 《Journal of Exotic Pet Medicine》2012,21(3):238-242
A 6-year-old spayed female ferret (Mustela putorius furo) exhibiting clinical signs of weakness, anorexia, lethargy, weight loss, and frequent urination was presented for a veterinary evaluation to determine the underlying cause of the aforementioned abnormal behavior and clinical condition. Physical examination revealed a large, firm, painless, movable subcutaneous mass at the base of the tail. Radiographic and ultrasound images confirmed the presence of a soft tissue mass compressing the sacrococcygeal vertebrae, but there was no evidence of metastatic lesions. Because of the poor prognosis and progressive deterioration of the animal's clinical condition, the ferret was humanely euthanized. Gross necropsy revealed a 4 × 4 × 3.5 cm, firm, yellow-tan, ovoid, subcutaneous mass wrapped around the rectum and the anus. The mass did not appear to breach the serosa. Evaluation of the abdominal cavity revealed a pale yellow liver, possibly associated with hepatic lipidosis with no gross evidence of metastasis in the body cavity. The histopathological features of the mass were consistent with a liposarcoma. To the best of the authors' knowledge, this is the first case of subcutaneous liposarcoma reported in a ferret. 相似文献