全文获取类型
收费全文 | 475篇 |
免费 | 53篇 |
专业分类
林业 | 27篇 |
农学 | 19篇 |
基础科学 | 5篇 |
102篇 | |
综合类 | 14篇 |
农作物 | 28篇 |
水产渔业 | 45篇 |
畜牧兽医 | 226篇 |
园艺 | 5篇 |
植物保护 | 57篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 14篇 |
2020年 | 18篇 |
2019年 | 23篇 |
2018年 | 20篇 |
2017年 | 29篇 |
2016年 | 25篇 |
2015年 | 10篇 |
2014年 | 9篇 |
2013年 | 40篇 |
2012年 | 25篇 |
2011年 | 40篇 |
2010年 | 17篇 |
2009年 | 24篇 |
2008年 | 22篇 |
2007年 | 31篇 |
2006年 | 31篇 |
2005年 | 23篇 |
2004年 | 19篇 |
2003年 | 12篇 |
2002年 | 16篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有528条查询结果,搜索用时 15 毫秒
81.
82.
A. Gromaz J. F. Torres A. San Bautista B. Pascual S. López-Galarza J. V. Maroto 《Journal of plant nutrition》2017,40(14):2045-5053
With the objective of studying the effect of two nutrient solutions and two crop systems (greenhouse and openfield) on nitrate accumulation, incidence of tipburn and chlorophyll content, endive (cv. Cuartana) was planted in 8 L pots, filled with a mixture of coconut coir:perlite (1:1) in three different cycles C1 (winter), C2 (spring) and C3 (summer). Plants were irrigated with two nutrient solutions of different nitrate content: S1, low ([NO?3] = 7.91 mmol L?1) and S2 moderate nitrate content ([NO?3] = 16.91 mmol L?1). Nitrate content was determined by reflectometry, tipburn was evaluated using a qualitative scale and chlorophyll content by soil plant analysis development(SPAD) values. Plants irrigated with S2 showed higher nitrate accumulation in leaves in all cycles, however, no influence of the nutrient solution was observed on the incidence of tipburn. Greenhouse-cultivated plants accumulated more nitrates than those cultivated in open field and also showed a higher incidence of tipburn and SPAD values. 相似文献
83.
84.
A quantitative trait loci (QTL) associated with resistance to pea rust, caused by the fungus Uromyces pisi (Pers.) Wint., has been identified in a F2 population derived from an intraspecific cross between two wild pea (Pisum fulvum L.) accessions, IFPI3260 (resistant) and IFPI3251 (susceptible). Both parental lines and all the segregating population displayed
a fully compatible interaction (high infection type), which indicates absence of hypersensitive response. Nevertheless, differences
on the percentage of symptomatic area of the whole plant (disease severity) were observed. A genetic map was developed covering
1283.3 cM and including 146 markers (144 random amplified polymorphic DNA (RAPDs) and two sequence tagged sites (STSs) markers)
distributed in 9 linkage groups. A QTL explaining 63% of the total phenotypic variation was located in linkage group 3. RAPDs
markers (OPY111316 and OPV171078) flanking this QTL should allow, after their conversion in SCARs, a reliable marker-assisted selection for rust resistance. 相似文献
85.
E. Escudero L. Vinué T. Teshager C. Torres M.A. Moreno 《Research in veterinary science》2010,88(1):83-87
Introduction
Fecal Escherichia coli isolates showing a phenotype of reduced susceptibility or resistance to extended-spectrum cephalosporins are common among pigs in Spain. The aim of this study was to describe the main beta-lactam resistance mechanisms carried by these strains and their distribution at farm-level.Materials and methods
Twenty-nine E. coli isolates showing reduced susceptibility or resistance to extended-spectrum cephalosporins were collected from a sampling frame of 80 pig farms distributed over 13 Spanish provinces. The survey was carried out at the slaughterhouse level in 2004.Results
Of the 29 isolates, 21 (72%) met the criteria for a positive phenotypic confirmatory test for extended-spectrum beta-lactamases (ESBL). The following ESBLs were detected: SHV-12 (12 isolates, 41%), CTX-M-1 (three isolates, 10%), CTX-M-9 (three isolates, 10%), and CTX-M-14 (three isolates, 10%). The remaining eight isolates (28%) were phenotypically non-ESBL, with seven of them (24%) showing mutations on the chromosomal ampC gene promoter at positions −42 (C → T), −18 (G → A), −1 (C → T), and +58 (C → T). A multiplex PCR for detection of plasmidic class C beta-lactamases was negative for all isolates.Conclusion
Different ESBLs and other mechanisms linked to extended-spectrum cephalosporin resistance are widely distributed among fecal E. coli from slaughter pigs in Spain. 相似文献86.
87.
C.E. Medina‐Torres J.S. Weese H.R. Staempfli 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2010,24(3):628-632
Background: Clostridium difficile infection (CDI) is a recognized cause of colitis in the horse. Identification of its toxins is important for management of individual cases and for prevention of transmission and zoonosis. In humans, CDI diagnosis is performed with enzyme immunoassays, none of which have been validated for horses. Hypothesis/Objectives: (1) Establish which test for CDI diagnosis was more frequently used by diagnostic laboratories, (2) determine the identified test's performance, sensitivity, and specificity, and (3) validate its use in diarrheic horses. Animals: Samples were obtained from 72 horses presented with acute diarrhea and hospitalized at the Ontario Veterinary College, University of Guelph. Methods: A survey was conducted to establish which of the tests for CDI diagnosis in horses is most commonly used throughout North America. A questionnaire was sent to all laboratories registered in the Veterinary Infection Control Society and the American Association of Veterinary Laboratory Diagnosticians. The performance of the test was evaluated by comparison to a cell cytotoxicity assay (CTA), the accepted Gold Standard for C. difficile toxin detection. Results: The Techlab C. difficile Tox A/B II ELISA was the most frequently used test. Compared with the CTA, no significant difference was observed, and a good level of agreement (93%) was obtained. The diagnostic performance of the ELISA test was adequate (84% sensitivity and 96% specificity). Conclusions and Clinical Importance: Results demonstrate that the Techlab C. difficile Tox A/B II ELISA is a reliable, adequate, and practical tool for identification of C. difficile toxins in horse feces. 相似文献
88.
Rafael Torres Neto Sandra De M.G. Bosco Renée L. Amorim Claudia V.S. Brandão Viciany E. Fabris Caroline Estanislau Eduardo Bagagli 《Veterinary dermatology》2010,21(2):202-204
This report describes a case of cutaneous pythiosis in a 6‐year‐old female mixed breed dog, from the central west region of São Paulo State, Brazil. The cytological and histopathological analyses showed an intense inflammatory infiltrate with presence of numerous hyphal elements, suggesting infection due to Pythium insidiosum. The diagnosis was confirmed by nested‐PCR, which was carried out with specific primers derived from the ribosomal DNA region. The pathogen occurs in Brazil and veterinarians should be aware of the importance of correctly diagnosing this disease and differentiating it from other fungal diseases. 相似文献
89.
Cesar D Freire Marcelo L A Torres Denise T Fantoni† Ruben L Cavalcanti‡ & Jessica Noel-Morgan† 《Veterinary anaesthesia and analgesia》2010,37(1):63-69
ObjectiveTo evaluate the extent sensory and motor blocks produced by the epidural injection of different volumes of 0.25% bupivacaine (Bu) with methylene blue (MB), in dogs.Study designProspective experimental trial.AnimalsTwenty healthy adult mongrel dogs, weighing 9.9 ± 1.9 kg.MethodsDogs were randomly allocated into one of four groups that received 0.2, 0.4, 0.6 or 0.8 mL kg?1 of an epidural solution containing 0.25% Bu and MB. Sensory block was evaluated against time by pinching the tail, hind limb interdigital web, toenail bases and the skin over the vertebral dermatomes. Motor block was assessed by ataxia, hind limb weight-bearing ability and by loss of muscle tone of the tail and pelvic limbs. Data were collected at 2, 5, 10, 15 and 30 minutes after the end of epidural injection. After the final time point, dogs were euthanatized and laminectomies were conducted to expose the extent of the dural dye staining.ResultsThe volumes 0.2, 0.4, 0.6 and 0.8 mL kg?1 of 0.25% Bu and MB blocked a mean of 5, 14.2, 20.2 and 21 dermatomes, respectively. The extent of the senory block increased up to a volume of 0.6 mL kg?1. Motor block was longer-lasting and more intense than sensory block. Complete dyeing of the spinal cord with MB was achieved in some dogs at 0.4 mL kg?1 and all dogs at 0.6 mL kg?1.ConclusionsThe volume of anesthetic injected into the epidural space plays an important role in the quality of the epidural anesthesia. At 0.25%, bupivacaine provided an efficient sensory block at 0.6 mL kg?1.Clinical relevanceRelatively high volumes (0.6 mL kg?1) of 0.25%, BU and MB were needed to produce an effective sensory and motor block caudal to the umbilicus, but all spinal cord segments were reached by MB at this dose. 相似文献
90.