全文获取类型
收费全文 | 537篇 |
免费 | 36篇 |
专业分类
林业 | 24篇 |
农学 | 9篇 |
基础科学 | 1篇 |
85篇 | |
综合类 | 45篇 |
农作物 | 31篇 |
水产渔业 | 73篇 |
畜牧兽医 | 246篇 |
园艺 | 20篇 |
植物保护 | 39篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 18篇 |
2020年 | 22篇 |
2019年 | 41篇 |
2018年 | 25篇 |
2017年 | 25篇 |
2016年 | 26篇 |
2015年 | 20篇 |
2014年 | 21篇 |
2013年 | 27篇 |
2012年 | 32篇 |
2011年 | 49篇 |
2010年 | 21篇 |
2009年 | 25篇 |
2008年 | 27篇 |
2007年 | 28篇 |
2006年 | 28篇 |
2005年 | 18篇 |
2004年 | 16篇 |
2003年 | 18篇 |
2002年 | 14篇 |
2001年 | 3篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1967年 | 1篇 |
1959年 | 1篇 |
1958年 | 3篇 |
排序方式: 共有573条查询结果,搜索用时 0 毫秒
511.
Kajal Chakraborty Selsa J. Chakkalakal Deepu Joseph Minju Joy 《Journal Of Aquatic Food Product Technology》2013,22(8):1172-1189
ABSTRACTNutritional composition of edible oysters (Crassostrea madrasensis) from the wild and cultured growth habitats from the southwest coast of India were evaluated over 4 years (2008–2011) during the premonsoon season. The important nutritional qualities of this species have been correlated with chlorophyll-a concentration, sea surface temperature, and phytoplankton density in their growth environments. The higher proportions of total polyunsaturated fatty acids, eicosapentaenoic, and docosahexaenoic acids in the edible oysters collected from the wild habitats were significantly correlated with chlorophyll-a concentration revealing the role of the phytoplanktons to contribute to the occurrence of these vital fatty acids. The ideal atherogenic index (AI); thrombogenicity index (TI); hypocholesterolemic/hypercholesterolemic ratio (HH); and balanced quantities of vitamins, minerals, amino acids, and low cholesterol contents qualified C. madrasensis as a potential health food. 相似文献
512.
We investigated the potential of Fraxinus americana L. to adapt to climate change by comparing diameter growth, survival and physiological status of 44 populations of 30-year-old trees originating from throughout the species range and grown in a common garden. Populations originating closest to the latitude of the common garden had the most rapid diameter growth and the highest survival. Among populations originating within a narrow latitudinal band along an east-west gradient of decreasing precipitation, those from the drier western end were best adapted to the dry climate of the common garden site, as judged by survival, stem circumference, leaf and wood carbon isotope ratios, leaf mass per area and leaf nitrogen concentration. These findings suggest that eastern populations may not perform well under the hotter and drier conditions predicted by climate change scenarios. Moreover, in the event of significant climate change, the short-term acclimation responses (within a generation) of F. americana may be insufficient to ensure the continued vigor or survival of this species throughout much of its present range. 相似文献
513.
Kruczkowska Bogusława Jonczak Jerzy Gadziszewska Joanna Niska Monika Florek Wacław Degórski Marek 《Journal of Soils and Sediments》2019,19(2):848-861
Journal of Soils and Sediments - The studies aimed to reconstruct major phases of litho-morpho-pedogenic processes and past environmental changes in the Baltic coastal zone near Podd?bie... 相似文献
514.
Louisa S Slingsby Joanna C Murrell Polly M Taylor 《Veterinary anaesthesia and analgesia》2010,37(2):162-170
ObjectiveTo evaluate the sedative and antinociceptive effects of combinations of dexmedetomidine and buprenorphine in cats.Study designExperimental randomized study.AnimalsTwelve purpose-bred neutered domestic short-hair cats (4 male and 8 female) weighing 4.6 kg (range 3.7–5.5 kg) aged from 2 to 5 years.MethodsSix cats per group were administered buprenorphine (B) at 10 (B10) or 20 μg kg?1 (B20) or dexmedetomidine (D) at 20 (D20) or 40 μg kg?1 (D40) or a combination of B10/D20. A feline thermal nociceptive threshold testing device was used to evaluate the antinociceptive effects of the drugs before and up to 24 hours after drug treatment. Sedation was scored using a 100 mm visual analogue scale (VAS).ResultsThermal thresholds increased significantly after administration of all but D20. Area under the curve (AUC, hours °C) for the first 6 hours (mean ± SD) for B20 (281 ± 17.8) was significantly greater than B10 (260 ± 11.4), D20 (250 ± 7.9) and D40 (255 ± 11.4). The AUC for B10/D20 (273 ± 12.2) was significantly greater than D20 but not the other treatments. No sedation was seen after administration of B10 or B20 and maximal sedation was seen for all animals in the D40 and B10/D20 groups and most animals in the D20 group.ConclusionsD20 alone had the smallest analgesic effect; B10 alone provided no sedation but their combination gave good sedation with analgesia comparable with B20.Clinical relevanceThis combination could be a useful multimodal sedative/analgesic regimen in cats. 相似文献
515.
<正>二十年前的19世纪80年代,营养学家们就意识到了仔猪教槽料和断奶日粮配方中所谓的酸结合因子的重要性,此后,这方面取得了长足发展。饲料配方中考虑负电解质平衡的思路不仅可用于小猪料,其他多种猪料中也可予以应用。 相似文献
516.
Monika Kosmala Joanna Milala Krzysztof Kołodziejczyk Jarosław Markowski Monika Mieszczakowska Christian Ginies Catherine M. G. C. Renard 《Plant foods for human nutrition (Dordrecht, Netherlands)》2009,64(4):279-285
The polysaccharide composition of cell wall of sour cherry (Prunus cerasus var. Schattenmorelle) fruit and pomace was investigated. Furthermore, the alcohol insoluble solids composition of ‘Kelleriis’
and ‘Dobreczyn Botermo’ varieties were studied too. Yield of alcohol insoluble solids for fruits was lower than 10%, and for
pomaces circa 50%. Uronic acid was the main pectin component of alcohol insoluble solids. Enzymes used as juice processing
aids decreased the content of uronic acid. Araban and galactan side chains bonded tightly to cellulose presence was suggested by high content of arabinose and galactose in hemicellulose fraction. The process of drying at below 70 °C did not influence polysaccharide
composition of sour cherry pomaces. Alcohol insoluble solids of fruits expressed higher hydration properties than of pomaces. 相似文献
517.
Growth enhancement of white rot fungus Phlebia brevispora TN3F by two bacterial strains TN3W-8 and TN3W-14 which showed high identity with genus Pseudomonas and Enterobacter, respectively, was investigated in liquid and solid media at different glucose concentrations. The white rot fungus P. brevispora TN3F and the bacterial strains were isolated from same white rot-decayed cedar wood from the Tano Forest Science Station at University of Miyazaki. Confrontational assay between the fungus and the bacterial strains revealed a fungal growth enhancement phenomenon, in the direction of the bacterial cells, even without direct contact. This enhancement increased with decrease of glucose concentration, 0.5% glucose offering comparatively the most mycelial growth. In potato extract (PE) medium at 0.5% glucose concentration, along with mycelial growth enhancement and morphological change of P. brevispora TN3F, growth and morphological enhancement of fungus TMIC33929, another strain of P. brevispora, was achieved by the bacterial strain TN3W-14, although TMIC33929 originated from a different environment. Outside few reports of a positive interaction between white rot fungi and other microorganisms, this is a first report of such positive interaction in liquid medium. Furthermore, this also is the first report of a single bacterium having potential to positively affect mycelia growth of different strains of a white rot fungus. 相似文献
518.
Marta Joanna Monder Andrzej Pacholczak 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2018,68(3):189-198
During rhizogenesis, carbohydrates are an important source of energy for the plant tissues. It has been hypothesised that phenological phase of the shoot plays a major role in plant's response to rooting stimulants and affects the cuttings’ carbohydrate content. Therefore, the purpose of this study was to evaluate the impact of phenological phase of the shoots and the use of rooting stimulants of plant origin on the relationship between rooting abilities and the carbohydrate content in leaves and stems of cuttings. Single-node stem cuttings of Rosa beggeriana ‘Polstjärnan’ and Rosa helenae ‘Semiplena’ were harvested from shoots in four phenological stages: flower buds closed (P1), flowers open (P2), immediately after petal shedding (P3), and 7–14 days after petal fall (P4). The following rooting enhancers were used: 0.4% indole butyric acid (IBA) (Ukorzeniacz Aaqua); 0.2% naphthalene acetic acid (NAA) (Ukorzeniacz Baqua); Bio Rhizotonic; and Root Juice?; Bio Roots. Controls included untreated cuttings. The contents of reducing and total soluble carbohydrates in leaves and shoots were estimated before and after rooting. The rooting percentage and rooting degree were determined. A relatively high or moderate natural rooting ability without any treatment were shown by R. beggeriana ‘Polstjärnan’ in 63.8%–87.5% and by R. helenae ‘Semiplena’ in 41.3%–72.5% cuttings. IBA and NAA decreased the mean rooting percentage in ‘Polstjärnan’, but increased it for P4 cuttings in ‘Semiplena’. None of the preparations had any impact on the degree of rooting. The mean level of total soluble and reducing sugars in leaves and stems of cuttings before rooting was lower than that of after root formation. The preparations of plant origin positively affected rhizogenesis and sugar contents in plant tissues, but their effect depended on shoot's phenological phase and cultivar. Plant origin preparations may successfully replace those containing IBA or NAA. 相似文献
519.
Claudio C. Natalini Carolina L. Krahn Priscila B.S. Serpa Joanna E. Griffith Ricardo Miyasaka de Almeida 《Veterinary anaesthesia and analgesia》2017,44(2):219-227
Objective
To investigate the efficacy of a new intravenous (IV) nanoemulsified isoflurane formulation for maintenance of general anesthesia in dogs.Study design
Prospective, crossover, experimental study.Animals
Seven healthy, mature, mixed-breed dogs, three male and four female, weighing 11.5 ± 1.5 kg.Methods
Anesthesia was induced with propofol for instrumentation. Measurements were obtained before administration of either inhaled isoflurane (Iso-I) or IV 15% isoflurane-loaded lipid nanoemulsion (Iso-nano). The minimum alveolar concentration (MAC) of isoflurane was determined using the ‘up-and-down’ technique. A tail clamp was applied every 15 minutes for a total time of 90 minutes and isoflurane administration was adjusted according to the response. Data were recorded at 30, 60 and 90 minutes for end-tidal isoflurane concentration (Fe´Iso), end-tidal carbon dioxide partial pressure (Pe′CO2), inspired isoflurane concentration (FIIso), arterial hemoglobin oxygen saturation (SaO2), peripheral hemoglobin oxygen saturation (SpO2), respiratory rate (fR), heart rate (HR), arterial blood pH, PaCO2, PaO2, base excess (BE), bicarbonate (HCO3?), systemic arterial pressure (sAP), and biochemical variables of blood urea nitrogen, alanine aminotransferase, creatine kinase and creatinine.Results
No significant differences between treatments were detected for HR, fR, SaO2 or any biochemical variables (p > 0.05). In the Iso-nano treatment, sAP was significantly decreased throughout the study. Significant decreases in pH, Pe′CO2, BE and HCO3? were measured in the Iso-nano treatment. Isoflurane MAC was significantly lower in the Iso-nano than the Iso-I treatment. The dose of isoflurane (g hour?1) required to maintain general anesthesia did not differ significantly between treatments.Conclusions and clinical relevance
Administration of 15% isoflurane-loaded lipid nanoemulsion IV was effective in maintaining general anesthesia in dogs but did not reduce the amount of isoflurane necessary to maintain general anesthesia. Significant hypotension and nonrespiratory acidosis occurred with the injectable form. 相似文献520.
Jeanne W. George Joy Snipes V. Michael Lane 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2010,39(2):138-148
Background: The most commonly used bovine hematology reference intervals were published in 1965. We found the results from healthy cattle in 2001 differed from those in many ways. Discovery of the original laboratory book used to calculate the 1965 values gave us the opportunity to evaluate whether hematology values of healthy cattle have changed over time. Objective: The purpose of this study was to establish hematology reference intervals for Holstein cows, compare selected hematologic results with similar population data from 1957, and compare these reference intervals with those of other North American veterinary schools and published values. Methods: Reference intervals were developed in 2001 using clinically healthy, bovine leukemia virus‐negative, mid‐lactation Holstein cows. Selected parts of the hemograms and neutrophil:lymphocyte (N:L) ratio were compared with those from healthy, age‐matched Holstein cows evaluated in 1957. Bovine reference intervals were solicited from clinical pathology laboratories in North American veterinary colleges and analyzed for population characteristics and method of analysis. Results: Between 1957 and 2001, mean neutrophil counts increased significantly, whereas lymphocyte, monocyte, and eosinophil counts and hemoglobin concentration decreased significantly. Mean N:L ratio increased significantly to 1.17. Most surveyed laboratories were using the 1965 reference intervals. Two other institutions that had developed reference intervals after 2000 had results similar to ours. Conclusions: Continued use of older bovine hematology reference intervals could lead to misinterpretation of within‐reference neutrophil counts as neutrophilia and under‐recognition of neutropenia, eosinophilia, monocytosis, or lymphocytosis. Use of N:L>1 as evidence of inflammation should be discontinued or used with great caution. 相似文献