全文获取类型
收费全文 | 186篇 |
免费 | 19篇 |
专业分类
林业 | 16篇 |
农学 | 2篇 |
基础科学 | 5篇 |
46篇 | |
综合类 | 8篇 |
农作物 | 22篇 |
水产渔业 | 32篇 |
畜牧兽医 | 58篇 |
植物保护 | 16篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 15篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 14篇 |
2016年 | 8篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 6篇 |
2012年 | 11篇 |
2011年 | 15篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 11篇 |
2007年 | 11篇 |
2006年 | 2篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 3篇 |
1999年 | 4篇 |
1996年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
排序方式: 共有205条查询结果,搜索用时 15 毫秒
61.
Jesus D. Celada Amelia Aguilera Jose M. Carral María Sáez-Royuela Pedro M. Melendre Jose R. Pérez 《Aquaculture International》2007,15(6):461-465
In two 120-day experiments, performed in the laboratory at 22°C, the effects of stocking density on the survival and growth
of juvenile tench (Tinca tinca L.) were evaluated. Fish were kept in fibreglass tanks, supplied throughout with flow of artesian water, and fed a dry diet
for salmonids, in excess, supplemented with restricted amounts of Artemia nauplii. In the first experiment four-month-old juveniles (0.31 ± 0.04 g and 32.00 ± 1.17 mm TL) were stocked at four densities—0.18,
0.88, 1.05, and 2.10 g l−1. Survival was high (>89%) for all treatments. Final densities ranged between 1.10 g l−1 (significantly lowest) and 10.46 g l−1 (significantly highest). The density increase was significantly higher (611%) for fish stocked at the lowest initial density
(0.18 g l−1) than for fish stocked at 0.88, 1.05, and 2.10 g l−1, for which the density increase averaged 457%. In the second experiment, 4.5-month-old juveniles (0.58 ± 0.17 g and 39.54 ± 0.83 mm
TL) were stocked at three densities—1.05, 3.00, and 4.00 g l−1. Survival was high (>96%) for all treatments. Final densities ranged between 4.08 and 16.53 g l−1 and were significantly higher for greater initial densities. The density increase was greatest (413%) for fish stocked at
the highest density (4 g l−1) and was not significantly different for fish stocked at 1.05 and 3 g l−1. Considering all the densities in the two experiments, for stocking at 4 g l−1 the final density was 15 times higher than that reached after stocking at 0.18 g l−1, without harmful effects on survival and growth. This final density (equivalent to 16.53 kg m−3) is in the range recommended for other fish species in this period under intensive conditions. 相似文献
62.
Mercury in the Aquatic Environment of the Village of Caimito at the Mojana Region,North of Colombia 总被引:1,自引:0,他引:1
Olivero-Verbel Jesus Johnson-Restrepo Boris Mendoza-Marín Claudia Paz-Martinez Ramon Olivero-Verbel Rafael 《Water, air, and soil pollution》2004,159(1):409-420
During May–September 1999, several aquatic environmental samples were collected from the village of Caimito, in the San Jorge River basin area, state of Sucre (Colombia), and analyzed for total mercury (T-Hg). Mean T-Hg concentration in sediments from surrounded marshes was 0.155 ± 0.016 g Hg/g. Low Hg concentrations were found in the phytoplanktivorous fish species Prochilodus magdalenae (0.087 ± 0.01 g Hg/g), while four-fold greater concentrations were found in all the carnivorous species. In average, T-Hg concentrations for fish samples did not exceed the limit consumption level (0.5 g Hg/g). However, risk assessment based on the hazard index suggested that the consumption of 0.1 kg per day of carnivorous fish could increase the risk of mercury poisoning in local population. 相似文献
63.
A comparative study of apple and pear tree water consumption measured with two weighing lysimeters 总被引:1,自引:1,他引:0
Joan Girona Jesus del Campo Merce Mata Gerardo Lopez Jordi Marsal 《Irrigation Science》2011,29(1):55-63
A five-year experiment (2002–2006) was conducted to determine apple (cv ‘Golden Smoothee’) and pear (cv ‘Conference’) crop
coefficients (Kc) using two large weighing lysimeters. Daily reference evapotranspiration (ETo) and crop evapotranspiration
(ETc) were evaluated. Midday canopy light interception of both crops planted in hedgerows, 4 × 1.6 m, was determined on a
weekly basis from bud-break until leaf fall from year 2002 (fourth after planting) to year 2006 of both plantations. Relationships
between canopy light interception and calculated Kc (ETc/ETo) were evaluated from bud-break until harvest. There were differences
in Kc values between apple and pear trees. When daily Kc values from bud-break until harvest were adjusted to hyperbolic functions
each year, adjusted curves for pear trees were very similar regardless of year (maximum Kc around 1.0). In apple trees, the
maximum values of Kc increased over time, from 0.49 in 2002 to 1.04 in 2006. Midday light interception in both apple and pear
trees increased during the 5 years of experiment from 29.0 to 45.6% in apples and from 27.5 to 41.6% in pears in midsummer.
Although there was a significant positive correlation between midday canopy light interception and Kc in apple and pear trees,
in different times within a specific year, these relationships were different between crops. While the apple data fitted into
the same equation regardless of the year, different equations were needed to fit the pear data in different years. This discrepancy
may have been related to differences in the canopy properties between apple and pear trees. Pear canopies had higher porosity
than apple canopies and thus improved light penetration. Apple trees were more vigorous and produced taller and denser canopies.
Pear Kc values were greatly influenced by the evaporative demands of different years and consequently differences in midday
canopy light interception did not adequately reflect the differences in Kc across the two species. 相似文献
64.
Tritrichomonas foetus is the causative agent of sexually transmitted trichomoniasis in cattle. In females, the infection can be associated with infertility, vaginitis, endometritis, abortion or pyometra, leading to significant economic losses in cattle raising. T. foetus is devoid of the ability to synthesize purine nucleotides de novo, depending instead on salvaging purines from the host environment. Ecto-5'-nucleotidase catalyzes the final step of extracellular nucleotide degradation, the hydrolysis of nucleoside 5'-monophosphates to the corresponding nucleosides and Pi. In this work we show that living, intact cells of T. foetus were able to hydrolyze 5'AMP at a rate of 12.57 ± 1.23 nmol Pi × h(-1) × 10(-7) cells at pH 7.2 and the 5'AMP hydrolysis is due to a plasma membrane-bound ecto-enzyme activity. The apparent K(m) for 5'AMP was 0.49 ± 0.06 mM. In addition to 5'AMP, the enzyme hydrolyzed all substrate monophosphates tested except 3'AMP. No divalent metals or metal chelators were able to modulate enzyme activity. Phosphatase inhibitors did not have an effect on ecto-5'-nucleotidase activity while ammonium molybdate did inhibit the activity in a dose dependent manner. The presence of adenosine in the culture medium negatively modulated the enzyme. These results indicate the existence of an ecto-5'-nucleotidase that may play a role in the salvage of purines. 相似文献
65.
Lozano-Sánchez J Giambanelli E Quirantes-Piné R Cerretani L Bendini A Segura-Carretero A Fernández-Gutiérrez A 《Journal of agricultural and food chemistry》2011,59(21):11491-11500
Phenolic compounds in extra virgin olive oil (EVOO) have been associated with beneficial effects for health. Indeed, these compounds exert strong antiproliferative effects on many pathological processes, which has stimulated chemical characterization of the large quantities of wastes generated during olive oil production. In this investigation, the potential of byproducts generated during storage of EVOO as a natural source of antioxidant compounds has been evaluated using solid-liquid and liquid-liquid extraction processes followed by rapid resolution liquid chromatography (RRLC) coupled to electrospray time-of-flight and ion trap mass spectrometry (TOF/IT-MS). These wastes contain polyphenols belonging to different classes such as phenolic acids and alcohols, secoiridoids, lignans, and flavones. The relationship between phenolic and derived compounds has been tentatively established on the basis of proposed degradation pathways. Finally, qualitative and quantitative characterizations of solid and aqueous wastes suggest that these byproducts can be considered an important natural source of phenolic compounds, mainly hydroxytyrosol, tyrosol, decarboxymethyl oleuropein aglycone, and luteolin, which, after suitable purification, could be used as food antioxidants or as ingredients in nutraceutical products due to their interesting technological and pharmaceutical properties. 相似文献
66.
Ricardo de la Fuente Jesus Almazan Esperanza Gomez-Lucia Jean Freney Guillermo Suarez 《Comparative immunology, microbiology and infectious diseases》1986,9(4):347-353
A total of 176 Gram-positive, catalase positive cocci strains, isolated from sheep were studied by different routine tests for the differentiation of staphylococci and micrococci, comparing their validity and usefulness. By glucose fermentation and growth in the anaerobic portion of thioglycolate 85 and 73.6% respectively of coagulase negative staphylococci were misclassified as Micrococcus spp. Susceptibility to lysostaphin was an adequate test for the differentiation of the strains. Atypical results in the production of acid from glycerol/erythromycin were obtained in 11.8% of the coagulase negative strains and 16.7% of micrococci. The combined use of the selective media furazolidone agar and Schleifer and Krämer medium resulted in a fast and useful separation of ovine staphylococci and micrococci. The bacteriolytic activity misclassified 32.2% of the coagulase negative strains. 相似文献
67.
Ginja MM Gonzalo-Orden JM Jesus SS Silvestre AM Llorens-Pena MP Ferreira AJ 《Veterinary journal (London, England : 1997)》2007,174(2):378-383
Simple and accurate limb and pelvic conformation evaluation using computed tomography (CT) can be useful in planning canine hip dysplasia (CHD) treatment and in helping to understand the pathogenesis of osteoarthritis and CHD. The objectives of this study were to describe a new method for femoral neck anteversion angle (FNA-angle) measurement in CT, and to compare it to the established radiographic standard biplanar method. The hips of 23 Estrela Mountain Dogs were evaluated using radiography and CT and their FNA-angles were determined by performing two CT examinations and with one radiographic measurement session. The intra-class correlation coefficient (ICC) was used to evaluate the repeatability (agreement between the two CT sessions, ICC=0.92) and reproducibility (agreement between each CT and radiographic session, ICC=0.91 in both cases) of the CT FNA-angle measurement method. This study suggests that CT FNA-angle measurement method is reliable and can be used in CT hip studies with confidence. 相似文献
68.
Grillo TP Brandão CV Mamprim MJ de Jesus CM Santos TC Minto BW 《The Canadian veterinary journal. La revue veterinaire canadienne》2007,48(7):745-747
A 6-year-old male, Belgian shepherd dog was presented with lethargy, oliguria, hematuria, and reluctance to move. The dog developed hypertrophic osteopathy secondary to renal pelvis transitional cell carcinoma. A nephrectomy was performed and after a year, the dog was completely asymptomatic, and no evidence of metastatic disease was present. 相似文献
69.
70.
IMAGING DIAGNOSIS—SPONTANEOUS PNEUMOMEDIASTINUM SECONDARY TO PRIMARY PULMONARY PATHOLOGY IN A DALMATIAN DOG
下载免费PDF全文
![点击此处可从《Veterinary radiology & ultrasound》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Amalia Agut Jesus Talavera Antonio Buendia Agustina Anson Giorgia Santarelli Serafin Gomez 《Veterinary radiology & ultrasound》2015,56(5):E54-E57
A 1.5‐year‐old, 23 kg intact male Dalmatian dog was evaluated for acute respiratory insufficiency without a previous history of trauma or toxic exposition. Imaging revealed pneumomediastinum, pneumothorax, diffuse unstructured interstitial pulmonary pattern, pulmonary interstitial emphysema, and pneumoretroperitoneum. Histopathological evaluation of the lungs revealed perivascular and peribronchial emphysema, mild lymphocytic interstitial pneumonia with atypical proliferation of type II pneumocytes in bronchioles and alveoli. A lung disease resembling fibrosing interstitial pneumonia in man and cats has been previously reported in Dalmatians and should be included as a differential diagnosis for Dalmatians with this combination of clinical and imaging characteristics. 相似文献