全文获取类型
收费全文 | 269篇 |
免费 | 15篇 |
专业分类
林业 | 16篇 |
农学 | 11篇 |
基础科学 | 3篇 |
67篇 | |
综合类 | 12篇 |
农作物 | 14篇 |
水产渔业 | 26篇 |
畜牧兽医 | 108篇 |
园艺 | 5篇 |
植物保护 | 22篇 |
出版年
2023年 | 8篇 |
2022年 | 12篇 |
2021年 | 22篇 |
2020年 | 20篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 13篇 |
2016年 | 14篇 |
2015年 | 3篇 |
2014年 | 16篇 |
2013年 | 15篇 |
2012年 | 11篇 |
2011年 | 19篇 |
2010年 | 11篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 14篇 |
2006年 | 7篇 |
2005年 | 11篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有284条查询结果,搜索用时 62 毫秒
71.
Aguzzi A 《Berliner und Münchener tier?rztliche Wochenschrift》2002,115(3-4):91-98
Our understanding of the pathogenesis of the transmissible spongiform encephalopathies (TSE) has made terrific headway over the past 40 years and some scientists are even of the opinion that this group of diseases belongs to the neurodegenerative syndromes best understood. On the other hand, the investigation of TSE has led to a multitude of unexpected and surprising results and consequently has initiated impassioned discussions among scientists. Although the human forms of TSE are very rare, the wildfire-like spread of the bovine spongiform encephalopathy (BSE) raises the pressing question as to whether BSE is communicable to humans. This overview summarizes some current hypotheses about the nature of the infectious agent and about the pathogenesis of the damage of the central nervous system. 相似文献
72.
Objective— To evaluate the efficacy of cryosurgery for treatment of skin and subcutaneous tumors in dogs and cats.
Study Design— Prospective study.
Animals— Dogs (n=20), cats (10).
Methods— Cutaneous or subcutaneous tumors were treated by liquid nitrogen cryosurgical spray (1 cm from target tissue at 90° until a 5-mm halo of frozen tissue was achieved) for 15–60 seconds. Malignant lesions had 3 freeze–thaw cycles benign tumors, 2 cycles. The second or third freeze cycle was performed after complete thaw of the preceding freeze. Wounds healed by second intention. Follow-up was weekly for 1 month and then twice monthly until wounds healed, and final outcome was determined by telephone interview of owners.
Results— Tumor size ranged from 0.3 to 11 cm diameter with 28 (60%) being 0.3–1 cm; 8 (17%) 1.1–3 cm, and 11 (23%) >3.4 cm. Complications included edema, erythema and for extremity lesions, pain and lameness. Treated lesions (n=47) had an overall remission of 98% (mean follow-up, 345±172.02 days [range, 150–750 days]). One malignant peripheral nerve sheath tumor recurred 7 months after cryosurgical treatment.
Conclusion— Cryosurgery is an efficient method for treatment of skin and subcutaneous tumors in dogs and cats.
Clinical Relevance— Cryosurgical ablation is an effective means of treating small cutaneous or subcutaneous tumors in dogs and cats, especially in older animals where wound closure or cosmetic outcome might limit surgical excision alone. 相似文献
Study Design— Prospective study.
Animals— Dogs (n=20), cats (10).
Methods— Cutaneous or subcutaneous tumors were treated by liquid nitrogen cryosurgical spray (1 cm from target tissue at 90° until a 5-mm halo of frozen tissue was achieved) for 15–60 seconds. Malignant lesions had 3 freeze–thaw cycles benign tumors, 2 cycles. The second or third freeze cycle was performed after complete thaw of the preceding freeze. Wounds healed by second intention. Follow-up was weekly for 1 month and then twice monthly until wounds healed, and final outcome was determined by telephone interview of owners.
Results— Tumor size ranged from 0.3 to 11 cm diameter with 28 (60%) being 0.3–1 cm; 8 (17%) 1.1–3 cm, and 11 (23%) >3.4 cm. Complications included edema, erythema and for extremity lesions, pain and lameness. Treated lesions (n=47) had an overall remission of 98% (mean follow-up, 345±172.02 days [range, 150–750 days]). One malignant peripheral nerve sheath tumor recurred 7 months after cryosurgical treatment.
Conclusion— Cryosurgery is an efficient method for treatment of skin and subcutaneous tumors in dogs and cats.
Clinical Relevance— Cryosurgical ablation is an effective means of treating small cutaneous or subcutaneous tumors in dogs and cats, especially in older animals where wound closure or cosmetic outcome might limit surgical excision alone. 相似文献
73.
Casulli A Manfredi MT La Rosa G Cerbo AR Genchi C Pozio E 《Veterinary parasitology》2008,155(1-2):168-172
To increase the knowledge on Echinococcus genotypes infesting cattle and water buffaloes (Bubalus bubalis) born and bred in Italy, the germinal layer of hydatid cysts was collected from the liver and the lungs of 80 animals slaughtered in 2007. Two mitochondrial genes (the cytochrome c oxidase subunit I and the NADH subunit I) were tested by PCR. Four genotypes were identified: G1 (sheep strain), G2 (Tasmanian sheep strain), G3 (buffalo strain), and G5 (cattle strain). Fertile cysts were detected only in the lungs of 4.5% of the total G1 lung cysts, of 9.4% of the total G3 lung cysts, and in the only G5 infected animal. This is the first report of Echinococcus ortleppi (genotype G5) in Italy. 相似文献
74.
75.
Adriano Carvalho Costa Hortência Aparecida Botelho Richardson Cesar da Silva Gomes Sergio Augusto de Sousa Campos Rafael Vilhena Reis Neto Marcio Balestre Fernanda Dotti do Prado Diogo Teruo Hashimoto Diego Galetti Martins Fbio Porto‐Foresti Mrio Lima Rilke Tadeu Fonseca de Freitas 《Aquaculture Research》2019,50(3):717-724
This work was carried out to predict the combining abilities, both general and specific, for performance traits and bodily yields of Serrasalmidae. Ninety‐six 30‐day‐old juveniles were purchased from two commercial fish farms, 12 of each of the following eight genetic groups: pacu, pirapitinga, tambaqui, tambacu, tambatinga, patinga, paqui and piraqui. Six fish from each genetic group were grown in 500‐L fibreglass tanks (two tanks per genetic group) until they were 495 days old. At the end of the growth period fish were weighed, subjected to morphometric analysis and processed to obtain their bodily yields. Two nuclear markers and one mitochondrial marker were used to confirm the identity of the animals. Combining abilities were obtained using the method proposed by Griffing in 1956 (Australian Journal of Biological Science, 4, 463–493) adapted to a mixed models analysis, environmental effects were estimated by the empirical best linear unbiased estimator method and genetic effects (general and specific combining abilities) were estimated with the empirical best linear unbiased predictor. Predictions of the combining abilities of advanced hybrids were obtained by the mixed models mixture method with normal distributions. Tambaqui showed higher general and specific combining abilities than the other groups for most of the variables, making it the most important genetic group. General combining ability makes a greater contribution to phenotypic variance than specific combining ability for most variables, indicating a predominance of genes with an additive effect in the control of evaluated traits. 相似文献
76.
77.
Ten isolates of Trypanosoma evansi from the Pantanal region of Brazil, recently derived from coati (Nasua nasua, carnivora, Procyonidae), horses and dogs, were characterized on the basis of biological (experimental infections in Wistar rats) and biochemical (multilocus enzyme eletrophoresis) data. Biological data were analyzed by Nested analysis of variance and Kruskal-Wallis. Marked heterogeneity in virulence was observed in the isolates. Some of the isolates showed an undulating parasitaemia, typical for African trypanosomes. This biological heterogeneity did not correspond with the biochemical homogeneity observed in the T. evansi isolates. T. evansi has one of the widest distributions and greatest range of mammalian hosts and is widely recognized to have evolved from Trypanosoma brucei. Adaptability of T. evansi was not reflected in the variability of biochemical and molecular parameters studied to date. The variability in virulence was very significant, but not correlated with the host from which it was derived. These data suggested that, in the region studied, T. evansi is transmitted among both domestic and sylvatic animals in one single transmission cycle. 相似文献
78.
Phytochemicals endowed with hormonal, antihormonal, or toxic activity are potential agents for insect control. The effect of some neolignans on one of the most prevalent flies in urban areas, which constitutes a menace to public health, was investigated. 相似文献
79.
Costa JF Kiperstok AC David JP David JM Giulietti AM de Queiroz LP dos Santos RR Soares MB 《Fitoterapia》2007,78(7-8):510-514
Ethyl acetate and chloroform extracts from aerial parts of Portulaca werdermannii and P. hirsutissima were tested in lymphoproliferation assays and axenic cultures of Leishmania amazonensis and Trypanosoma cruzi. Both extracts of P. werdermannii and P. hirsutissima had a potent inhibitory activity on lymphocyte proliferation. On the contrary, only the chloroformic extract of both plants inhibited L. amazonensis growth, without effect on T. cruzi cultures. These results indicate these Portulaca species as potential sources of new active molecules for the treatment of leishmaniasis and immune-mediated pathologies. 相似文献
80.
Coffee quality and its relationship with Brix degree and colorimetric information of coffee cherries
S. de A. Silva D. M. de Queiroz F. de A. C. Pinto N. T. Santos 《Precision Agriculture》2014,15(5):543-554
Coffee is a product whose value is stipulated according to its quality, which in turn depends on the stage of maturity of its fruits—the more mature its fruits, the higher the coffee value. The objective of this work was to analyze the level of soluble solids in coffee samples, determine the spectral signature of the fruits and their chromatic information, and correlate this information with the global quality of the beverage. Coffee cherry samples were collected from four plantations in the municipality of Araponga, Minas Gerais, Brazil. They were submitted to spectral and colorimetric analyses and used to determine the Brix degree. The samples were submitted to a quality test to determine the global coffee quality. The results were submitted to Pearson’s analysis of correlation followed by spatial variability mapping of each variable in each plantation. A linear regression analysis was also conducted to generate models capable of explaining the relationship between variables. Global coffee quality has significant correlation only with R band and fruit reflectance values. It is possible to use information from these variables to predict coffee quality while still in the plantation field. 相似文献