全文获取类型
收费全文 | 775篇 |
免费 | 62篇 |
专业分类
林业 | 49篇 |
农学 | 29篇 |
基础科学 | 4篇 |
205篇 | |
综合类 | 22篇 |
农作物 | 38篇 |
水产渔业 | 81篇 |
畜牧兽医 | 303篇 |
园艺 | 28篇 |
植物保护 | 78篇 |
出版年
2023年 | 8篇 |
2022年 | 16篇 |
2021年 | 38篇 |
2020年 | 38篇 |
2019年 | 44篇 |
2018年 | 34篇 |
2017年 | 40篇 |
2016年 | 29篇 |
2015年 | 15篇 |
2014年 | 30篇 |
2013年 | 54篇 |
2012年 | 52篇 |
2011年 | 72篇 |
2010年 | 26篇 |
2009年 | 38篇 |
2008年 | 39篇 |
2007年 | 42篇 |
2006年 | 32篇 |
2005年 | 32篇 |
2004年 | 36篇 |
2003年 | 19篇 |
2002年 | 25篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1969年 | 2篇 |
1963年 | 2篇 |
1961年 | 1篇 |
排序方式: 共有837条查询结果,搜索用时 15 毫秒
1.
The purpose of this study was to evaluate the clinicopathological aspects of experimental sporotrichosis in cats and compare the sensitivity of cytopathology, histopathology and culture as diagnostic tools in different phases of the infection. Twenty adult, mixed‐breed cats (10 males and 10 females) were inoculated subcutaneously with 106 fungal microorganisms. Clinical examination was performed weekly. Cytopathologic, histopathologic and culture examinations were performed at 15, 30 and 60 days postinoculation. Culture of multiple organs was performed after euthanasia at 30 (10 cats) and 60 (10 cats) days postinoculation. Friedman parametric and nonparametric statistical analysis were applied to the results. The nodular, tumoral and necrotic lesionsprogressed significantly until day 30 postinoculation, and partial spontaneous regression occurred at day 60, particularly in males. An intense inflammatory pyogranulatomous and lymphocytic infiltrate with rare giant cells and sparse fibrosis associated with numerous, pleomorphic, intra‐ and extracellular fungal cells were observed on day 30. These findings gradually decreased by day 60. Despite the inflammatory granuloma associated with feline sporotrichosis, a tendency for dissemination was observed, with fungal isolation in the lymph nodes, spleen and liver at the 30 and 60 days postinoculation. No significant differences were observed between cytopathology, histopathology and fungal culture during the different phases of the disease. Therefore, cytological examination was considered a simple, rapid and inexpensive diagnostic method at all stages of this disease. Funding: Self‐funded. 相似文献
2.
Paixão Sonália Ferreira Fritzen Juliana Torres Tomazi Crespo Sarah Elizabeth Izzo de Moraes Pereira Helder Alfieri Alice Fernandes Alfieri Amauri Alcindo 《Tropical animal health and production》2018,50(8):1947-1950
Tropical Animal Health and Production - Serological studies have characterized the presence of the bovine viral diarrhea virus (BVDV) infection in water buffalo herds worldwide. However, the... 相似文献
3.
4.
Ana Carina Heil da Silva Matos Angélica Consalter Bárbara Paula dos Santos Batista Ana Beatriz Monteiro Fonseca Ana Maria Reis Ferreira Juliana da Silva Leite 《Reproduction in domestic animals》2021,56(4):667-672
Granulosa cell tumour, an ovarian neoplasm of stromal origin, is an important tumour related to oestrogenic dominance syndrome and cystic endometrial hyperplasia–pyometra complex. In order to analyse ovarian tumour´s malignant potential, immunohistochemical markers can be used, such as anti-HER2 and anti-Ki-67. The aim of this study was to evaluate the expression of immunohistochemical markers HER-2 and Ki-67 in granulosa cell tumour from bitches´ ovaries. In HER-2 immunomarker analysis using the HercepTest® method, most tumours were classified as 2+ (moderate labelling). Concerning Ki-67 immunomarker, only one case was described as having a high proliferative index. An association was found between immunostained cell percentage by anti-HER-2 antibodies and high pleomorphism, represented by the pattern of follicular/trabecular tumour arrangement. There was no correlation between anti-Ki-67 and anti-HER-2 antibody immunostaining intensities, probably due to only one case with a high Ki-67 index. With an effective protocol for HER-2 and Ki-67 immunohistochemical identification in granulosa cell tumours in bitches, it was possible to characterize this neoplasm proliferation profile. 相似文献
5.
Effect of farm characteristics and practices on hygienic quality of ovine raw milk used for artisan cheese production in central Italy
下载免费PDF全文
![点击此处可从《Animal Science Journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Elisa Carloni Annalisa Petruzzelli Giulia Amagliani Giorgio Brandi Francesco Caverni Piermario Mangili Franco Tonucci 《Animal Science Journal》2016,87(4):591-599
A survey on ovine dairy farms directly transforming own‐produced milk, in the Italian Marche region, was carried out to assess flock and milking practices that may influence milk hygienic‐sanitary conditions. A census survey established that 24 dairy farms were located in this region. Bulk milk samples were collected throughout the milking period in each dairy farm in 2013. Analyzed variables were: (i) chemical parameters such as fat, protein and lactose content, dry matter and pH; and (ii) total bacterial (TBC) and somatic cell counts (SCC). Chemical parameter values were in agreement with published data while, geometric mean (GM) log10 SCC was 5.91 and TBC GM was 57 978 colony forming units/mL, in compliance with Eropean Union criteria. A positive correlation was found between SCC and TBC when GMs of all farm data were considered (Spearman's rho = 0.7925; P = 0.0001). Statistical analysis did not show significant correlation between SCC or TBC GM and dairy farm principal characteristics. Although SCC levels detected in the present study should suggest the need to implement mastitis control programs, Marche's dairy sheep flocks revealed a good hygienic condition level. This is an important aspect in implementing safety for end users of the final product. 相似文献
6.
7.
Varroa destructor (Mesostigmata: Varroidae) is arguably the most damaging parasitic mite that attacks honey bees worldwide. Since its initial host switch from the Asian honey bee (Apis cerana) (Hymenoptera: Apidae) to the Western honey bee (Apis mellifera) (Hymenoptera: Apidae), Varroa has become a widely successful invasive species, attacking honey bees on almost every continent where apiculture is practiced. Two haplotypes of V. destructor (Japanese and Korean) parasitize A. mellifera, both of which vector various honey bee-associated viruses. As the population of Varroa grows within a colony in the spring and summer, so do the levels of viral infections. Not surprisingly, high Varroa parasitization impacts bees at the individual level, causing bees to exhibit lower weight, decreased learning capacity, and shorter lifespan. High levels of Varroa infestation can lead to colony-wide varroosis and eventually colony death, especially when no control measures are taken against the mites. Varroa has become a successful parasite of A. mellifera because of its ability to reproduce within both drone cells and worker cells, which allows populations to expand rapidly. Varroa uses several chemical cues to complete its life cycle, many of which remain understudied and should be further explored. Given the growing reports of pesticide resistance by Varroa in several countries, a better understanding of the mite’s basic biology is needed to find alternative pest management strategies. This review focuses on the genetics, behavior, and chemical ecology of V. destructor within A. mellifera colonies, and points to areas of research that should be exploited to better control this pervasive honey bee enemy. 相似文献
8.
Naresh K. Bainsla Rahul M. Phuke Xinyao He Vikas Gupta Santosh K. Bishnoi Rajiv K. Sharma Najibeh Ataei Susanne Dreisigacker Philomin Juliana Pawan K. Singh 《Plant pathology》2020,69(6):1161-1171
Spot blotch (SB), caused by Bipolaris sorokiniana, is a devastating disease of wheat globally, especially in South Asia and South America. Understanding the genetics of resistance to SB is important for developing breeding strategies to improve resistance. A panel of 301 genotypes from Afghanistan was phenotyped over two crop seasons using a mixture of virulent B. sorokiniana isolates and genotyped using DArTSeq to obtain genome-wide markers. Fifty genotypes (16.6%) showed disease scores less than the resistant control. Principal component analysis using the genotypic data clustered the genotypes into five different groups. Among models used for genome-wide association mapping, the multilocus mixed model, and fixed and random model circulating probability unification algorithms were most effective in identifying significant marker-trait associations (MTA). Twenty-five MTAs at p ≤ .001 were identified on chromosomes 1A, 1B, 1D, 2B, 2D, 3A, 3B, 4A, 5A, 5B, 6A, 7A, and 7D, indicating the quantitative nature of resistance to SB. Phenotypic variation explained by these markers ranged from 2.0% to 17.7%, and genomic regions on the chromosomes 1D, 2D, 3A, 3B, 4A, 5A, and 5B coincided with loci identified in previous studies. Three single nucleotide polymorphism (SNP) markers on chromosomes 1B (SNP 1113207) and 5A (SNPs 5411867 and 998276) were significant in both crop seasons as well as in the combined analysis across seasons. Marker 5411867 is close to Vrn-A1, shown to be associated with SB in previous studies. Furthermore, among known SB resistance genes, Sb2 on chromosome 5B was predicted to be significant in this panel. 相似文献
9.
Manfredi Di Lorenzo Paolo Guidetti Antonio Di Franco Antonio Cal Joachim Claudet 《Fish and Fisheries》2020,21(5):906-915
Overfishing may seriously impact fish populations and ecosystems. Marine protected areas (MPAs) are key tools for biodiversity conservation and fisheries management, yet the fisheries benefits remain debateable. Many MPAs include a fully protected area (FPA), restricting all activities, within a partially protected area (PPA) where potentially sustainable activities are permitted. An effective tool for biodiversity conservation, FPAs, can sustain local fisheries via spillover, that is the outward export of individuals from FPAs. Spillover refers to both: “ecological spillover”: outward net emigration of juveniles, subadults and/or adults from the FPA; and “fishery spillover”: the fraction of ecological spillover that directly benefits fishery yields and revenues through fishable biomass. Yet, how common is spillover remains controversial. We present a meta‐analysis of a unique global database covering 23 FPAs worldwide, using published literature and purposely collected field data, to assess the capacity of FPAs to export biomass and whether this response was mediated by specific FPA features (e.g. size, age) or species characteristics (e.g. mobility, economic value). Results show fish biomass and abundance outside FPAs was higher: (a) in locations close to FPA borders (<200 m) than further away (>200 m); (b) for species with a high commercial value; and (c) in the presence of PPA surrounding the FPA. Spillover was slightly higher in FPAs that were larger and older and for more mobile species. Based on the broadest data set compiled to date on marine species ecological spillover beyond FPAs' borders, our work highlights elements that could guide strategies to enhance local fishery management using MPAs. 相似文献
10.
Histological alterations in gills of shrimp Litopenaeus vannamei in low‐salinity waters under different stocking densities: Potential relationship with nitrogen compounds
下载免费PDF全文
![点击此处可从《Aquaculture Research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Marcela G. Fregoso‐López María S. Morales‐Covarrubias Miguel A Franco‐Nava Javier Ramírez‐Rochín Juan F Fierro‐Sañudo Jesús T Ponce‐Palafox Federico Páez‐Osuna 《Aquaculture Research》2017,48(12):5854-5863
Two experimental modules with different stocking densities (M1 = 70 and M2 = 120 shrimp /m2) were examined weekly over a culture cycle in tanks with low‐salinity water (1.9 g/L) and zero water exchange. Results showed survival rates of 87.7 and 11.9% in M1 and M2, respectively. Water temperature, pH, dissolved oxygen, electrical conductivity and chlorophyll a were not significantly (p > .05) different between modules. In contrast, the concentrations of nitrogen compounds were significantly (p < .05) different between modules, except nitrite‐N (M2 were 2.31 ± 1.38 mg/L N‐TAN, 0.18 ± 0.49 mg/L N‐NO2? and 6.83 ± 6.52 mg/L N‐NO3?; in M1: 0.97 ± 0.73 mg/L N‐TAN, 0.05 ± 0.21 mg/L N‐NO2? and 0.63 ± 0.70 mg/L N‐NO3?). When waters of both modules reached higher levels of ammonia and nitrite, histological alterations were observed in gills. The histological alterations index (HAI) was higher in M2 (5‐112) than in M1 (2‐22). 相似文献