全文获取类型
收费全文 | 154篇 |
免费 | 29篇 |
专业分类
林业 | 5篇 |
农学 | 1篇 |
10篇 | |
综合类 | 3篇 |
农作物 | 9篇 |
水产渔业 | 20篇 |
畜牧兽医 | 119篇 |
植物保护 | 16篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 8篇 |
2016年 | 17篇 |
2015年 | 13篇 |
2014年 | 9篇 |
2013年 | 30篇 |
2012年 | 7篇 |
2011年 | 5篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1985年 | 1篇 |
排序方式: 共有183条查询结果,搜索用时 192 毫秒
71.
72.
73.
Renan O. Silva Ana Paula M. Santana Nathalia S. Carvalho Talita S. Bezerra Camila B. Oliveira Samara R. B. Damasceno Luciano S. Chaves Ana Lúcia P. Freitas Pedro M. G. Soares Marcellus H. L. P. Souza André Luiz R. Barbosa Jand-Venes R. Medeiros 《Marine drugs》2012,10(12):2618-2633
Red seaweeds synthesize a great variety of sulfated galactans. Sulfated polysaccharides (PLSs) from seaweed are comprised of substances with pharmaceutical and biomedical potential. The aim of the present study was to evaluate the protective effect of the PLS fraction extracted from the seaweed Gracilaria birdiae in rats with naproxen-induced gastrointestinal damage. Male Wistar rats were pretreated with 0.5% carboxymethylcellulose (control group—vehicle) or PLS (10, 30, and 90 mg/kg, p.o.) twice daily (at 09:00 and 21:00) for 2 days. After 1 h, naproxen (80 mg/kg, p.o.) was administered. The rats were killed on day two, 4 h after naproxen treatment. The stomachs were promptly excised, opened along the greater curvature, and measured using digital calipers. Furthermore, the guts of the animals were removed, and a 5-cm portion of the small intestine (jejunum and ileum) was used for the evaluation of macroscopic scores. Samples of the stomach and the small intestine were used for histological evaluation, morphometric analysis and in assays for glutathione (GSH) levels, malonyldialdehyde (MDA) concentration, and myeloperoxidase (MPO) activity. PLS treatment reduced the macroscopic and microscopic naproxen-induced gastrointestinal damage in a dose-dependent manner. Our results suggest that the PLS fraction has a protective effect against gastrointestinal damage through mechanisms that involve the inhibition of inflammatory cell infiltration and lipid peroxidation. 相似文献
74.
75.
76.
Caio Rodrigo Dias de Assis Amanda Guedes Linhares Vagne Melo Oliveira Renata Cristina Penha França Juliana Ferreira Santos Marina Marcuschi Elba Verônica Matoso Maciel Carvalho Ranilson Souza Bezerra Luiz Bezerra Carvalho Jr. 《Fish physiology and biochemistry》2014,40(6):1659-1668
Brain cholinesterases from four fish (Arapaima gigas, Colossoma macropomum, Rachycentron canadum and Oreochromis niloticus) were characterized using specific substrates and selective inhibitors. Parameters of catalytic efficiency such as activation energy (AE), k cat and k cat/k m as well as rate enhancements produced by these enzymes were estimated by a method using crude extracts described here. Despite the BChE-like activity, specific substrate kinetic analysis pointed to the existence of only acetylcholinesterase (AChE) in brain of the species studied. Selective inhibition suggests that C. macropomum brain AChE presents atypical activity regarding its behavior in the presence of selective inhibitors. AE data showed that the enzymes increased the rate of reactions up to 1012 in relation to the uncatalyzed reactions. Zymograms showed the presence of AChE isoforms with molecular weights ranging from 202 to 299 kDa. Values of k cat and k cat/k m were similar to those found in the literature. 相似文献
77.
Maura da Cunha Darlí Grativol Keller Ivan Cunha Bustamante Filho Jorge André Sacramento de Magalhães Valdirene Moreira Gomes Wanderley de Souza José Inácio Lacerda Moura José Luiz Bezerra Flávio Costa Miguens 《Journal of General Plant Pathology》2010,76(1):74-83
Phytomonas wilt or Hartrot is a fatal disease of palm (Arecaceae) species including Cocos nucifera (coconut) and is caused by a phloematic trypanosomatid, a promastigote parasite that inhabits phloem sieve elements of disease
palms. In the present work, we described the morphology of the interaction between a phloematic trypanosomatid (Phytomonas staheli) and C. nucifera. Two varieties and one ecotype of the adult coconut palm from northeast and southeast Brazil were analyzed, totaling 34,000
plants. Coconut palm losses due to Hartrot varied according to the variety or ecotype and geographic area. Occurrence of Hartrot
was insignificant in Rio de Janeiro state (southeast), but in Bahia state (northeast) losses were substantial when appropriate
cultural practices were not applied. Symptomatic and healthy palm tissues were analyzed by light and electron microscopy.
Laboratory diagnoses revealed the twisted promastigote form of phloematic trypanosomatids in the extracts of shoot apex, leaves,
stems and inflorescence in diseased plants, but not in the healthy ones. No parasites were found in the roots. Although the
general anatomy of healthy and diseased palms was similar, callose deposition in the sieve plates was revealed by histochemistry
and immunocytochemistry in the diseased tissue. Plugging by the P-protein and plastid alterations was also observed. Our observations
strongly suggest that parasite traffic between sieve elements took place, although their cell bodies were larger than the
sieve pores. Phloematic trypanosomatid proliferation in the sieve tube elements might interrupt the transport of phloem or/and
consume plant nutrients. In addition, an association between the percentage of sieve elements colonized by pathogen in palm
tissues and disease severity was established. 相似文献
78.
The tunneling resistance between two ferromagnetic metal layers that are separated by a thin insulator depends on the relative orientation of the magnetization M of each layer. In a memory device, independent switching of the magnetically soft layer is achieved by making the other layer either exchange-biased or magnetically hard. The repeated reversal of M of the soft layer by field cycling can demagnetize the other magnetically hard layer and thus erase the tunnel junction's memory. The M of exchange-biased structures was stable at least to 10(7) cycles, whereas in hard structures, M generally decayed logarithmically with the number of field cycles. The decay was very sensitive to the thickness of the hard layer and the composition of the soft layer. However, no decay was observed when the moment reversal was accomplished by coherent rotation, establishing that demagnetization results from the formation and motion of domain walls in the soft layer during field cycling. 相似文献
79.
D.A. Grossi O.G. Frizzas C.C.P. Paz L.A.F. Bezerra R.B. Lbo J.A. Oliveira D.P. Munari 《Livestock Science》2008,117(2-3):139-146
The total meat yield in a beef cattle production cycle is economically very important and depends on the number of calves born per year or birth season, being directly related to reproductive potential. Accumulated Productivity (ACP) is an index that expresses a cow's capacity to give birth regularly at a young age and to wean animals of greater body weight. Using data from cattle participating in the “Program for Genetic Improvement of the Nelore Breed” (PMGRN — Nelore Brasil), bi-trait analyses were performed using the Restricted Maximum Likelihood method based on an ACP animal model and the following traits: age at first calving (AFC), female body weight adjusted for 365 (BW365) and 450 (BW450) days of age, and male scrotal circumference adjusted for 365 (SC365), 450 (SC450), 550 (SC550) and 730 (SC730) days of age. Median estimated ACP heritability was 0.19 and the genetic correlations with AFC, BW365, BW450, SC365, SC450, SC550 and SC730 were 0.33, 0.70, 0.65, 0.08, 0.07, 0.12 and 0.16, respectively. ACP increased and AFC decreased over time, revealing that the selection criteria genetically improved these traits. Selection based on ACP appears to favor the heaviest females at 365 and 450 days of age who showed better reproductive performance as regards AFC. Scrotal circumference was not genetically associated with ACP. 相似文献
80.
Rosivaldo Quirino Bezerra Júnior Ângela Maria Xavier Eloy João Ricardo Furtado Raymundo Rizaldo Pinheiro Alice Andrioli Frederico Bruno Moreno Marina Duarte Pinto Lobo Ana Cristina O. Monteiro-Moreira Renato de Azevedo Moreira Tatiana Maria Farias Pinto Maria Fátima da Silva Teixeira 《Tropical animal health and production》2018,50(1):43-48
The caprine arthrite encephalite (CAE) is a disease that affects especially dairy goat. The virus shows compartmentalization features, that allows it to hide at certain times during the course of the disease, making it difficult to control. The present study was conducted to identify the major seminal plasma protein profile of goats infected by CAE and its associations with seroconversion using Western blotting. Two groups containing five males each, were used in this experiment. The first group was composed by seropositive animals and the control by seronegative confirmed by Western blotting and PCR. The semen was collected through artificial vagina and after that, two-dimensional electrophoresis and MALDI-TOF MS were used. Seventy-five spots were identified in the goat seminal plasma gels, equivalent to 13 different proteins with more expression. The similar proteins found in both groups and related to reproduction were spermadhesin Z13-like, bodhesin and bodhesin-2, Lipocalin, protein PDC-109-like, and albumin. In infected goats, proteases such as arisulfatase A have been identified, whose function probably is related to metabolism control of sulfatides, involved to virus control. The other ones were bifunctional ATP-dependent dihydroxyacetone kinase/FAD-AMP lyase, cathepsin F isoform X1, disintegrin and metalloproteinase domain-containing protein 2-like isoform X1, clusterin, carbonic anhydrase 2, electron transfer flavoprotein subunit beta, and epididymal secretory glutathione peroxidase. The results of this study show the reaction of the innate immune system against chronic infection of goats by CAE. 相似文献