全文获取类型
收费全文 | 440篇 |
免费 | 39篇 |
专业分类
林业 | 32篇 |
农学 | 33篇 |
基础科学 | 1篇 |
77篇 | |
综合类 | 17篇 |
农作物 | 18篇 |
水产渔业 | 44篇 |
畜牧兽医 | 210篇 |
园艺 | 6篇 |
植物保护 | 41篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 22篇 |
2020年 | 16篇 |
2019年 | 25篇 |
2018年 | 26篇 |
2017年 | 27篇 |
2016年 | 17篇 |
2015年 | 18篇 |
2014年 | 25篇 |
2013年 | 37篇 |
2012年 | 21篇 |
2011年 | 23篇 |
2010年 | 25篇 |
2009年 | 20篇 |
2008年 | 15篇 |
2007年 | 22篇 |
2006年 | 15篇 |
2005年 | 17篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 11篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1980年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有479条查询结果,搜索用时 15 毫秒
91.
Matheus V. L. Moreira Maria C. de Andrade Gustavo O. Fulgêncio Ingeborg M. Langohr Roselene Ecco 《Veterinary ophthalmology》2018,21(5):535-538
An indoor‐only, 5‐year‐old, spayed female domestic shorthair cat presented for an ophthalmic examination of the left eye. An intraocular tumor with secondary glaucoma and blindness was diagnosed; the globe was enucleated and sent for histopathological examination. Gross examination revealed a solid white mass filling the entire vitreous space and replacing the iris and ciliary body. The lens and retina appeared to be similarly replaced by the neoplasm. Histological examination revealed a complete loss of the internal ocular structures, with a ruptured capsule as the only remnant of the lens within an extensive malignant mesenchymal neoplastic cell proliferation. The cells were polygonal, with well‐defined cytoplasmic borders and abundant weakly basophilic cytoplasm, embedded within the islands of chondroid matrix. No neoplastic invasion of the sclera was apparent. The animal died 6 months after the enucleation due to respiratory distress. Gross examination revealed numerous firm, white to tan nodular masses with smooth to mildly irregular surfaces dispersed throughout the parietal pleura, thoracic surface of the diaphragm, tracheobronchial and mediastinal lymph nodes, pericardium, and lungs. On cross‐section, the neoplastic nodules were solid and variably translucent, resembling hyaline cartilage. Histologically, these nodules were similar to the neoplasm identified earlier in the left globe. Metastasis of post‐traumatic ocular chondrosarcoma has not yet been described in cats. This is therefore believed to be the first report of metastases of this type of neoplasm in cats. This case adds to the limited set of data on the outcome of this type of tumor. 相似文献
92.
Gildacio Pereira Chaves Filho Lucas Alighieri Neves Costa Batista Silvia Regina Batistuzzo de Medeiros Hugo Alexandre Oliveira Rocha Susana Margarida Gomes Moreira 《Marine drugs》2022,20(8)
Sulfated polysaccharides (SPS) from seaweeds have great biochemical and biotechnological potential. This study aimed to investigate the effect of SPS isolated from the seaweed Caulerpa sertularioides on adipogenic differentiation as a possible alternative treatment for obesity. The SPS-rich extract from the seaweed C. sertularioides was fractioned into three SPS-rich fractions (F0.5; F0.9; and F1.8) chemically characterized. Among these four samples, only F0.9 showed a significant inhibitory effect on adipogenesis of 3T3-L1 preadipocytes. Ten SPS-rich fractions were isolated from F0.9 through ion-exchange chromatography. However, only the fraction (CS0.2) containing a sulfated glucan was able to inhibit adipogenesis. CS0.2 reduces lipid accumulation and inhibits the expression of key adipogenic (PPARγ, C/EBPβ, and C/EBPα) and lipogenic markers (SREBP-1c, Fabp4, and CD36). The data points to the potential of sulfated glucan from C. sertularioides for the development of functional approaches in obesity management. 相似文献
93.
Molecular typing of Mycobacterium bovis isolates from south-east Brazil by spoligotyping and RFLP 总被引:2,自引:0,他引:2
Zanini MS Moreira EC Salas CE Lopes MT Barouni AS Roxo E Telles MA Zumarraga MJ 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2005,52(3):129-133
The identification of 163 strains of Mycobacterium bovis by polymerase chain reaction (PCR) and microbiological tests was carried out on 252 tuberculous-like lesions (TLLs) collected from slaughtered cattle in south-east Brazil. This study compared the usefulness of three genotyping techniques, IS6110-restriction fragment length polymorphism (RFLP), polymorphic guanine-cytosine-rich sequence (PGRS)-RFLP and direct repeat (DR)-spoligotyping, as applied to M. bovis isolates. Based on IS6110-RFLP genotyping we selected a group of 23 isolates containing more than one IS6110 copy, along with 16 samples containing one IS6110 copy from different geographical areas, evenly distributed among dairy (eight) and beef cattle (eight). These selected isolates were analysed by PGRS-RFLP and DR-spoligotyping genotyping. Dairy cattle (17%) display a higher frequency of multiple IS6110 copies than beef cattle (10%). A comparison between the genotype data obtained fails to show a correlation between the main clusters found by the three techniques. However, the clustering of each genotyping procedure revealed that the majority of strains are closely related. The RFLP-PGRS patterns showed a sizable group (20.5%) containing a 5.5 kb fragment and the predominant spoligotype is similar to that from the BCG vaccine strain. Unexpectedly, four strains (2.4%) showed drug resistance to 0.2 microg/ml isoniazid and 20 microg/ml ethionamide, but none of them was resistant to rifampicin or other antibiotics tested. 相似文献
94.
Phosphorus (P) is required by crop plants for many physiological and biochemical functions. Knowledge of phosphorus uptake and its use by crop plants is essential for adequate management of this essential nutrient. A field experiment was conducted during four consecutive years to determine P uptake and use efficiency by upland rice, dry bean, corn and soybean grown in rotation on a Brazilian Oxisol. Plant samples were taken at different growth stages during the growth cycle of each crop for phosphorus analysis. Phosphorus concentration (content per unit dry matter) significantly decreased in a quadratic fashion with the advancement of plant age in four crop species. Phosphorus concentration was higher in legumes compared to cereals. Phosphorus uptake in shoot, however, significantly increased in an exponential quadratic fashion with the advancement of plant age of crop species. At harvest, P uptake was higher in grain compared to shoot, indicating importance of this element in improving crop yields. Phosphorus use efficiency (grain or straw yield per unit P uptake) was higher in cereals compared to legumes. The P use efficiency for grain production was 465 kg kg?1 for upland rice, 492 kg kg?1 for corn, 229 kg kg?1 for dry bean and 280 kg kg?1 for soybean. The higher P use efficiency in cereals was associated with higher yield of cereals compared to legume species. 相似文献
95.
HM Alves IRS Oliveira TS Castelo GL Lima ALP Souza MAP Moreira VV de Paula AR Silva 《Reproduction in domestic animals》2013,48(3):506-511
This study aimed to evaluate various concentrations of egg yolk (5, 10, or 20%) in combination with different concentrations of glycerol (3% or 6%) added to a Tris‐based extender on the post‐thaw characteristics of sperm obtained from Tayassu tajacu. For this purpose, semen from 10 sexually male mature collared peccaries was collected by electroejaculation and evaluated for sperm motility, vigour, viability, morphology and functional membrane integrity. The ejaculates were initially extended in Tris‐fructose plus egg yolk (5%, 10% or 20%). After cooling, the semen was added to Tris‐egg yolk plus glycerol (6% or 12%), resulting in a final concentration of 3% or 6% glycerol of the extender. Straws were frozen using liquid nitrogen and thawed in a water bath at 37°C for 30 s. The frozen–thawed semen was evaluated as reported for fresh semen. After thawing, a significant decrease was verified for sperm motility and vigour, for all the samples in comparison with fresh semen. However, no differences were evidenced among treatments for any sperm characteristics evaluated (p > 0.05), except for the combination between 10% egg yolk and 6% glycerol, which provided the worst preservation of functional membrane integrity (p < 0.05). The interactions between higher concentrations of egg yolk (20%) and glycerol (6%) and also between lower concentrations of the same substances (5% egg yolk and 3% glycerol) added to the Tris‐based extender negatively affected the preservation of the normal sperm morphology after thawing (p < 0.05). In conclusion, the use of Tris‐based extender added to 10% or 20% egg yolk plus 3% glycerol is recommended for effective sperm cryopreservation in collared peccaries. 相似文献
96.
Andr Moreira Souza Rodrigo de Andrade Santos Weigert Elaine Parros Machado de Sousa Lucas Tassoni Andrietta Ricardo Vieira Ventura 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2022,139(1):100-112
The objective of our study was to provide practical directions on the storage of genomic information and novel phenotypes (treated here as unstructured data) using a non-relational database. The MongoDB technology was assessed for this purpose, enabling frequent data transactions involving numerous individuals under genetic evaluation. Our study investigated different genomic (Illumina Final Report, PLINK, 0125, FASTQ, and VCF formats) and phenotypic (including media files) information, using both real and simulated datasets. Advantages of our centralized database concept include the sublinear running time for queries after increasing the number of samples/markers exponentially, in addition to the comprehensive management of distinct data formats while searching for specific genomic regions. A comparison of our non-relational and generic solution, with an existing relational approach (developed for tabular data types using 2 bits to store genotypes), showed reduced importing time to handle 50M SNPs (PLINK format) achieved by the relational schema. Our experimental results also reinforce that data conversion is a costly step required to manage genomic data into both relational and non-relational database systems, and therefore, must be carefully treated for large applications. 相似文献
97.
Rosa RM Melecchi MI da Costa Halmenschlager R Abad FC Simoni CR Caramão EB Henriques JA Saffi J de Paula Ramos AL 《Journal of agricultural and food chemistry》2006,54(19):7324-7330
The genus Hibiscus thrives in a variety of climates and produces a diversity of natural compounds with bioactive properties. We have studied the chemical composition and the in vivo antioxidant properties of Hibiscus tiliaceus L. methanolic flower extract, as well as its mutagenic/antimutagenic effects. Vitamin E and some stigmasterol derivatives that might confer an antioxidant effect to the extract were present. Treatment with this extract protected several Saccharomyces cerevisiae strains defective in antioxidant defenses against H2O2 and t-BOOH cytotoxicities, showing a clear antioxidant activity. The effect is the same for all strains used, independent of the antioxidant defense disrupted, suggesting that protection may be due to molecules that act as versatile and wide spectrum nonenzymatic antioxidants, such as vitamins or phytosterols. The extract was not mutagenic in either Salmonella typhimurium or S. cerevisiae and showed a significant antimutagenic action against oxidative mutagens in S. cerevisiae. 相似文献
98.
Campos E Moraes J Façanha AR Moreira E Valle D Abreu L Manso PP Nascimento A Pelajo-Machado M Lenzi H Masuda A Vaz Ida S Logullo C 《Veterinary parasitology》2006,138(3-4):349-357
The present work evaluates the kinetics of utilization of the main potential energy sources throughout the embryonic developmental stages of Boophilus microplus. The embryonic development of this arthropod is completed in 21 days. Cellularization of the blastoderm occurs on the 6th day and is rapidly followed by germ band extension and segmentation, whose first signs are visible on the 7th day. Cellularization is typically a maternal-driven process, carried out by molecular determinants deposited in the oocyte during oogenesis. On the other hand, segmentation is of zygotic nature, being the consequence of the synthesis of various components by the growing embryo. The enhancement in total B. microplus RNA was observed after cellularization, corroborating the replacement of maternal-driven processes by embryonic zygotic expression. An abrupt increase in oxygen consumption was observed from cellularization until the 8th day of development. The reduction in dry weight at the same period and the susceptibility of oxygen consumption to KCN suggest that the respiration process is activated during early embryonic development. A marked decrease in total lipid content occurred between the 5th and 7th days of development, suggesting this is the main energy source for cellularization. A major reduction in carbohydrate content occurred later, between the 7th and 9th days, and it could be assigned to the morphological segmentation of the embryo. Although the total amount of proteins remains unchanged from oviposition to hatching, a 15% reduction in vitellin (VT) content was observed before cellularization, up to the 4th day after egglaying. This observation was correlated to the synthesis of new proteins needed to support early embryo development. Additional 20% of VT was consumed thereafter, mainly at the end of embryogenesis, and in this case VT is probably used as energy source to the older embryo. Altogether, these data indicate different energy sources for maternal and zygotic driven processes. 相似文献
99.
A. G. C. Signoretti M. F. G. V. Peñaflor L. S. D. Moreira N. C. Noronha J. M. S. Bento 《Journal of pest science》2012,85(1):101-107
Herbivore-attacked plants produce specific volatile substances that represent important cues for host finding by natural enemies. The fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is a voracious herbivore and usually feed on maize in all periods of the day. Given that plant needs light to synthesize de novo herbivore-induced volatiles, volatile blend may be changed depending on time of the day the plant is induced, what could interfere in natural enemy foraging. In this sense, the current study aimed to investigate differential attractiveness of maize elicited by fall armyworm regurgitant under light and dark conditions to its specialist larval parasitoid Campoletis flavicincta (Ashmead) (Hymenoptera: Ichneumonidae). All bioassays were conducted in Y-tube olfactometer to assess parasitoid response to odors from undamaged maize, mechanical damage, and regurgitant-treated plants at 0–1, 5–6, and 24–25 h after induction. The results showed that naïve wasps were attracted to volatiles emitted by nocturnal regurgitant-treated maize at 5–6 h, but not to odors from diurnal regurgitant-treated plants. The differential attractiveness is likely due to blend composition as nocturnal regurgitant-treated plants emit aromatic compounds and the homoterpene (3E)-4,8-dimethyl-1,3,7-nonatriene in larger amounts than diurnal-treated plants. 相似文献
100.
Leandro Maia MV MS Maria Vernica de Souza MV MS DS Pharmacist-Biochemical Jos Ivo Ribeiro Júnior BS MS DS Acio Carlos de Oliveira Geraldo Eleno Silveira Alves MV MS DS Larcio dos Anjos Benjamin MV MS DS Yamê Fabres Robaina Sancler Silva Bruna Mota Zandim MV Jos do Carmo Lopes Moreira MD MS 《Journal of Equine Veterinary Science》2009,29(8):618-626
This study was carried out to evaluate the effect of platelet-rich plasma (PRP) on the treatment of tendinopathy induced in the superficial digital flexor tendon (TFDS) of horses, by using histologic evaluation. Six healthy crossbred geldings aged 8 to 15 years (12 ± 3) were used. The TFDS tendinopathy was provoked in both forelimbs, by intratendinous administration of 2.5 mg collagenase (2.5 mg/mL), and this procedure was considered as the beginning of the experimental phase. At 12 days after induction of the tendinopathy, the animals were subjected to the following treatments: (1) in the lesion caused in the right superficial digital flexor tendon (PRP-treated group), 2.5 mL PRP activated with calcium chloride at 0.0125 mol/L at concentrations from 320,000 to 500,000 platelets/μL, were injected; (2) in the tendinopathy of the left SDFT (control group), 2.5 mL 0.9% saline solution was administrated. Thirty-six days after the treatments, a biopsy of the injured area was performed for histologic evaluation. In both groups, the histologic analysis showed an increase in the fibroblastic density, as well as the presence of neovascularization, lymphocytes, and plasmocytes infiltrate and tissue organization at variable intensity. In the PRP-treated group, the SDFT was more organized, with the collagen fibers and fibroblasts being better arranged on the tendon matrix. The numbers of the fibroblasts and blood vessels did not differ between the groups. Histologic evaluation 36 days after tendinopathy showed that injuries under a single PRP treatment present a more uniform and organized tissue repair when compared with the control group. 相似文献