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排序方式: 共有637条查询结果,搜索用时 15 毫秒
41.
The aim of this study was to characterize the impacts of a conventional, an organic apple orchard and a native grassland on the activity and diversity of arbuscular mycorrhizal fungi (AMF) located at the south of Brazil during winter and summer. AMF activity was measured by the mycorrhizal inoculum potential (MIP), mycorrhizal fungal hyphal length (HL), easily extractable and total Bradford-reactive soil protein (BRSP). AMF diversity was represented by richness, Shannon diversity index and number of spores. Orchards reduced the MIP of the soil and increased the HL when compared to the grassland site. The amount of easily extractable BRSP was not different among orchards and between seasons evaluated, with overall mean value of 1.23 mg g−1. However, the amount of total-BRSP was smaller in the conventional orchard (4.55 mg g−1) than in the organic orchard (4.91 mg g−1) and in the native grassland (5.12 mg g−1). T-BRSP and total organic carbon were strongly correlated in the grassland during the winter, suggesting the contribution of this protein for carbon stocks in the native soil of this region. The organic orchard presented the highest AMF richness, but sporulation and Shannon diversity index were larger in the conventional orchard. Our data suggest that the conventional orchard promoted higher impacts on the natural condition of AMF activity, being considered an unadvisable practice to soil conservation. 相似文献
42.
Fábio R. C. F. César Takashi Muraoka Rodrigo C. da Silva Luiz Francisco Souza-Filho 《Journal of plant nutrition》2020,43(18):2773-2784
Abstract A possible way to improve phosphate rock (PR) agronomic performance is through the addition of elemental sulfur (S0). We used 32P isotope dilution method to assess the P taken up by crops treated with PR. Two experiments, one with common bean and other with upland rice, were carried out, to evaluate the effect of S0 on the agronomic performance of two contrasting PR, applied in different methods. Gafsa (GPR) and Patos de Minas (PPR) were used as the high and low reactivity PR, respectively. The experiments were arranged in completely randomized design on factorial structure 2?×?2 × 2?+?2; which means 2 PR (GPR and PPR) versus 2?S0 condition (with or without-S0) versus 2 application methods (band and broadcast) plus 2 additional treatments (control and triple superphosphate). In band application the S0 increased the amount of P uptake by plants from fertilizer of GPR from 2.57 to 9.86?mg pot?1 for common bean and of 2.26 to 7.05?mg pot?1 to rice. Regardless the management adopted, less than 2% of P applied as PPR has been taken up by crops. The addition of S0 as a strategy to increase the agronomic performance of PR is PR characteristics dependent and fertilizers placement. 相似文献
43.
The authors have examined the gross anatomy of the lymph-nodes and lymph-vessels of 77 newborn, young and adult white rats (Rattus norvegicus). Anatomical differences occuring in age were described in detail. 相似文献
44.
Detection of the enterotoxins A, B, and C genes in Staphylococcus aureus from goat and bovine mastitis in Brazilian dairy herds 总被引:2,自引:0,他引:2
To determine the distribution of genes that encode enterotoxins A, B and C, 36 strains of Staphylococcus aureus isolated from goat mastitis and 64 isolated from bovine mastitis were analyzed by Multiplex PCR. Of the total strains studied, 37 (37%) were detected to have some of the SEs genes. From the bovine mastitis strains, 4 (6.3%) co-amplified the sea and seb genes and 2 (3.1%) were positive for the sec gene. From the goat mastitis strains, 31 (86%) tested positive to the Multiplex, and the sec gene was detected in all of them. The production of SE was detected in all strains harboring the corresponding gene. The results demonstrated that S. aureus isolated from goat mastitis had a higher enterotoxigenic potential than those isolated from bovine mastitis. Additionally, the presence of the sec gene in the majority of goat mastitis strains suggests a possible involvement of SEC in goat mastitis pathogenesis. 相似文献
45.
Dueger EL George LW Angelos JA Tankersley NS Luiz KM Meyer JA Portis ES Lucas MJ 《American journal of veterinary research》2004,65(9):1185-1188
OBJECTIVE: To evaluate the efficacy of ceftiofur crystalline-free acid (CCFA) administered into the posterior aspect of an ear for treatment of corneal ulceration associated with naturally occurring infectious bovine keratoconjunctivitis (IBK). ANIMALS: 78 beef calves located at Sierra Foothills Field Station (SFS) and 52 calves located at a commercial dairy (CD). All calves were from 3 to 9 months old. PROCEDURE: At each site, calves were randomly allocated to 1 of 2 treatment groups by use of a block design determined by corneal ulcer size. A single dose of CCFA (6.6 mg of ceftiofur equivalents/kg, s.c.) was administered into the posterior aspect of a pinna. A second group of calves received a single dose of vehicle (0.03 mL/kg, s.c.; controls). Corneal ulcers were photographed, and clinical signs were assessed in calves every 3 to 4 days for 21 days. RESULTS: A positive treatment effect was detected at SFS. Results at the CD were inconclusive because ulcer healing occurred rapidly in control and CCFA-treated calves. At SFS, treatment with CCFA resulted in shorter mean healing times, smaller corneal ulcer surface area measurements, amelioration of ocular discharge and photophobia, and a 50% increase in the percentage of calves healed by day 14. After adjustment for initial corneal ulcer size, treatment with CCFA resulted in a 4-fold increase in the odds of corneal ulcer healing by day 14, compared with controls. CONCLUSIONS AND CLINICAL RELEVANCE: A single dose of CCFA administered into the posterior aspect of a pinna had a positive treatment effect against naturally occurring IBK in calves with corneal ulcerations. 相似文献
46.
Pigatto JA Andrade MC Laus JL Santos JM Brooks DE Guedes PM Barros PS 《Veterinary ophthalmology》2004,7(3):205-208
The objective of this study was to examine the endothelial surface morphology and to perform morphometric analysis of the corneal endothelial cells of Yacare caiman (Caiman yacare) using scanning electron microscopy. Morphometric analysis with regard to polygonality, mean cell area, cell density and coefficient of variation of mean cell area was performed. Cell areas were measured using image analysis software. The normal corneal endothelium of Yacare caiman consisted of polygonal cells of uniform size and shape with interdigitations of the cell borders. Microvilli appeared as protrusions on the cellular surface. The average cell area was 270 +/- 24 microm(2) and the endothelial cell density was 3704 +/- 324 cells/mm(2). The coefficient of variation of cell area was 0.22. This study demonstrates that the Yacare caiman corneal endothelium is similar to those described in other vertebrates. 相似文献
47.
Maraisa Crestani Solange Ferreira da Silveira Silveira Elisane Weber Tessmann Itamara Mezzalira Henrique de Souza Luche José Antonio Gonzalez da Silva Luiz Carlos Gutkoski Fernando Irajá Félix de Carvalho Antonio Costa de Oliveira 《Euphytica》2012,185(1):139-156
There has been a strong demand for oat genotypes that contain caryopsis with high chemical quality which can suit the different market niches. Therefore, the objectives of this study were to assess the general (GCA) and specific combining ability (SCA) of white oat cultivars through diallelic crosses providing information about the genetic effects on expression of grain chemical quality components. Also, it was aimed to estimate the heterosis on F1 and F2 generations and the vigor loss due to inbreeding. During 2008, 21 hybrid populations F1 and F2 were obtained from artificial crossing among seven Brazilian white oat cultivars, following the complete diallel design, without considering the reciprocals. These populations and their parents were evaluated in the 2009 season in the experimental field in Capão do Leão, RS, Brazil. The higher values of mean squares associated to GCA indicates a strong contribution of additive genetic effects to the expression of grain chemical components. The parents tested showed a tendency to develop progeny with negative heterosis regarding protein, lipid, β-glucan and soluble dietary fiber in the grain, and positive for the content of nitrogen-free extract, total and insoluble dietary fiber. IAC 7 features a potential parent for obtaining grains with high protein and dietary fiber content, and low caloric content, fit to human diet. Meanwhile, UPF 15 and FAPA Louise can represent donors of alleles to increase lipid contents, while FAPA Louise and URS Guapa can be used to raise the grain nitrogen-free extract contents of lines intended for animal feeding. 相似文献
48.
Dairy goat production systems 总被引:1,自引:1,他引:0
Luis Escareño Homero Salinas-Gonzalez Maria Wurzinger Luiz Iñiguez Johann Sölkner Cesar Meza-Herrera 《Tropical animal health and production》2012,45(1):17-34
Goat production concentrated in developing countries (tropics, dry areas), contributes largely to the livelihoods of low and medium income farmers. Farming systems in these areas have evolved to cope with the formidable constraints imposed by harsh natural and economic conditions by adapting integrated crop/livestock production strategies. In Asia, Africa and Latin America, due to its almost exclusive extensive nature, goat production relies mainly on grazing on communal lands that hardly provide the minimum nutrient requirements due to overstocking and degradation. While some of these production systems are becoming semi-intensive, appropriate breeding strategies should be designed to promote conservation and improvement of their unique attributes, such as adaptability, water use efficiency and suitability under harsh climatic conditions. In Europe, dairy goat production is more common around the Mediterranean basin, where it is important from an economic, environmental and sociological perspective to the Mediterranean countries: Spain, France, Italy and Greece. Europe owns only 5.1 % of the world’s dairy goat herds, but produces 15.6 % of the world’s goat milk; this is the only continent where goat milk has such an economic importance and organization. In developing countries the dairy goat sector requires a systemic approach, whereby nutrition, animal health, breeding, know-how, inputs and technologies must be assembled. This would allow the optimization of natural and local resources and would promote the transition from a risk reduction strategy towards an increased productivity strategy. Such an increase would privilege production efficiency based on clean, green and ethical practices for responsible innovation. 相似文献
49.
Gomes Pöppl Á Costa Valle S Hilário Díaz González F de Castro Beck CA Kucharski LC Silveira Martins Da Silva R 《Veterinary research communications》2012,36(1):81-84
Estrus cycle is a well recognized cause of insulin resistance in bitches. The insulin receptor (IR) as well as the insulin-like
growth factor-I receptor belong to the same subfamily of tyrosine kinase (TK) receptors. The objective of this study was to
evaluate basal TK activity in muscle tissue of bitches during the estrus cycle. Twenty-four bitches were used in the study
(7 in anestrus, 7 in estrus, and 10 in diestrus). Muscle samples, taken after spaying surgery to determine TK activity, were
immediately frozen in liquid nitrogen and then stored at −80°C until the membranes were prepared by sequential centrifugation
after being homogenized. TK activity was determined by Poly (Glu 4:Tyr 1) phosphorylation and expressed in cpm/μg of protein.
TK activity was significantly lower (P < 0.001) in the animals in estrus (104.5 ± 11.9 cpm/μg of protein) and diestrus (94.5 ± 16.9 cpm/μg of protein) when compared
with bitches in anestrus (183.2 ± 39.2 cpm/μg of protein). These results demonstrate, for the first time, lower basal TK activity
in the muscle tissue of female dogs during estrus and diestrus, which may represent lower insulin signaling capacity, opening
a new field of investigation into the molecular mechanisms of insulin resistance in dogs. 相似文献
50.
Silva-Almeida M Carvalho LO Abreu-Silva AL Souza CS Hardoim DJ Calabrese KS 《Veterinary research》2012,43(1):10
ABSTRACT: Leishmania is inoculated, by the bite of an infected sandfly, into the skin of the host, where the promastigotes are phagocyted by dermal macrophages. The dermal region comprises cells and abundant extracellular matrix. Studies show that matrix metalloproteinases play an important role in host defense responses against pathogens in mammals and that their activities lead to the production of antimicrobial peptides. The aim of this study is to evaluate the changes in the distribution of fibronectin and laminin as well as in the elastic system fibres during the course of infection caused by Leishmania amazonensis in mice with distinct genetic backgrounds of susceptibility to this parasite. The results showed that BALB/c presented an enhancement of fibronectin during the course of infection when compared to their control group while the infected or non-infected C3H.He showed a decrease of this protein at end of the experiment. Laminin, on the other hand, remained unaltered in both strains. Also in both BALB/c and C3H.He mice the elastic and elaunin fibres remained unchanged while the oxytalan fibres decreased along the experiment. Ninety days after the infection C3H.He mice had recovered their capacity to produce oxytalan fibres. 相似文献