首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   436篇
  免费   29篇
林业   58篇
农学   7篇
基础科学   5篇
  87篇
综合类   4篇
农作物   31篇
水产渔业   49篇
畜牧兽医   147篇
园艺   33篇
植物保护   44篇
  2024年   1篇
  2023年   6篇
  2022年   10篇
  2021年   12篇
  2020年   10篇
  2019年   11篇
  2018年   34篇
  2017年   27篇
  2016年   25篇
  2015年   14篇
  2014年   17篇
  2013年   37篇
  2012年   17篇
  2011年   32篇
  2010年   16篇
  2009年   20篇
  2008年   27篇
  2007年   21篇
  2006年   14篇
  2005年   32篇
  2004年   17篇
  2003年   26篇
  2002年   18篇
  2001年   7篇
  2000年   4篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1995年   1篇
  1991年   1篇
  1986年   2篇
  1979年   1篇
  1978年   1篇
  1962年   1篇
排序方式: 共有465条查询结果,搜索用时 15 毫秒
391.
Tropical Animal Health and Production - The aim of this study was to investigate the possible risk of bovine viral diarrhea virus transport from imported live animals. For this purpose, two...  相似文献   
392.
The pineal gland is a neuroendocrine organ associated with photoperiodic regulation in mammals. The aim of this study was to evaluate the pineal gland at the pre‐pubertal, pubertal and post‐pubertal periods by means of morphology and stereology. The study examined at total of 24 ovine pineal glands collected from healthy female Akkaraman breed. Thick sections (40 μm) were cut and treated with synaptophysin. Following each thick section, six consecutive sections at a thickness of 5 μm were cut. Each thin section was stained with one of the following dyes: Crossman’s modified triple dye, glial fibrillary acidic protein (GFAP), melatonin marker, periodic acid–Schiff, Von Kossa and AgNOR. The pineal gland volume was measured using Cavalieri’s method. The optical fractionator was used to estimate the total number of pinealocytes. The percentage of parenchyma and connective tissue and degree of vascularization were estimated by the area fraction fractionator method. The pineal gland volumes in the pre‐pubertal, pubertal and post‐pubertal groups were 7.53 ± 1.715 mm3, 11.20 ± 1.336 mm3 and 17.75 ± 1.188 mm3, respectively (p < .5). The number of pinealocytes in the pre‐pubertal, pubertal and post‐pubertal groups was 3,244,000 ± 228,076, 4,438,000 ± 243,610, 7,381,766 ± 406,223, respectively (p < .05). The glands of the post‐pubertal group contained the highest amount of connective tissue (11.49 ± 2.103%; p < .5) and the largest GFAP staining area (p < .05). The melatonin staining density was the highest in the pubertal group. The density of lipofuscin staining was higher in the pubertal and post‐pubertal groups.  相似文献   
393.
The physiological responses of cherry rootstocks were evaluated under moderate salinity in short term. MaxMa 14, CAB-6P and Mazzard rootstocks were treated with 35?mM NaCl solution for 1 month to assess physiological responses. Under NaCl stress, rootstocks’ physiological parameters were compared with their own control, with the greatest alterations in SPAD value, leaf relative water content (LRWC), membrane permeability and stomatal conductivity. SPAD value was reduced by 9.5, 2.17 and 2.27% in saline-treated plants of MaxMa 14, CAB-6P and Mazzard, respectively. MaxMa 14 and CAB-6P exhibited a rapid decrease in stomatal conductivity by 39.90 and 47.60%, respectively compared with their control, while in Mazzard there was a reduction by 5.28% compared with its control. Moreover, LRWC of the plants decreased by 11.24 and 13.75% in salt-treated MaxMa 14 and CAB-6P, respectively. In comparison, a lower reduction of LRWC (6.11%) was observed in NACl-treated Mazzard. As seen in the result of experiment, the inhibitory effects of NaCl were less in Mazzard compared with MaxMa 14 and CAB-6P.  相似文献   
394.
Many seeds of woody plants require low temperature for germination and that’s called seed dormancy has been investigated for relations of proteins by several researchers. We determined polypeptide profiles of cold-stratified Mazzard seeds. Seeds were studied in five different periods: seeds in dormancy (none stratified), 30, 60, 90 and 120 days cold-stratified. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) of the soluble protein fractions from stratified and none stratified seeds was utilized for determination of changes in polypeptides. SDS-PAGE revealed a decrease in the concentrations of 14 polypeptides and appearance of four low-molecular weight (15.1, 16.3, 17.8 and 19.4?kDa) polypeptides were determined in 90 and 120 day stratified seeds. The study results exhibited the evidences of the involvement of protein changes in response of Mazzard seeds during cold stratification.  相似文献   
395.
Reference genes are essential for the normalisation of the expression data of quantitative real-time PCR for the purposes of validation. Although several reference genes have been validated for the olive, comprehensive analyses including an excessive number of candidate reference genes still require study in various olive tissue samples. In this work, a total of 40 candidate reference genes were tested for their stability in 8 different olive tissues (root, apical bud, lateral bud, pedicel, young leaf, mature leaf, fruit mesocarp, and seed) with the utilisation of the most popular software programs including GeNorm, NormFinder, BestKeeper, and ΔCt. The analyses of expression stability of candidate reference genes using quantitative real-time PCR demonstrated ubiquitin-conjugating enzyme (UBC1) as the most stable reference gene for the studied tissues of the olive. The GeNorm software also calculated the optimum reference gene combinations as two which consist of UBC1 and the Clathrin adaptor complex medium subunit (CLATHRIN) genes. This study provides the most stable reference gene combination for normalisation of target genes for quantitative real-time PCR gene expression studies on the olive.  相似文献   
396.
We determined the effect of different storage systems and packaging on the quality of ‘Sultana Seedless’ raisins. The fruit were packed in plastic boxes and kept under controlled atmosphere (1% O2 and 3% CO2) at 0°C and 75–85% RH for 12 months (CA), packed in vacuum bags and kept under normal atmosphere (21% O2–0.03% CO2) (NA) and packed in thin plastic bags + carton boxes and kept under ambient condition (semi-refrigeration), at 0°C and 90% ± 5 RH for 12 months (AC). Fruit kept under CA or NA had acceptable fruit quality in terms of general appearance and taste for 10 months, whereas fruit quality was unacceptable at that time under AC. Fruit under NA had less weight loss than fruit under the other conditions. Differences in skin colour were relatively small, apart from the h° values. Concentrations of ochratoxin A were generally higher with AC. External appearance and taste were better with CA and NA. As a result, raisins can be stored for 10 months with good quality in vacuum package in NA (0°C and 90% ± 5 RH) and CA (1% O2–3% CO2) at 0°C and 75–85% RH.  相似文献   
397.
In this study, fruit quality characteristics of some cultivars and types of fig (Ficus carica L.) were determined in Dortyol, Hatay, Turkey, which has a Mediterranean climate. The main fig cultivars grown in Turkey (‘Sarilop’, ‘Bursa Siyahi’, ‘Goklop’, ‘Yediveren’, ‘Yesilguz’, ‘Morguz’, ‘Sari Zeybek’, and ‘Ufak Yesil’) were evaluated along with 24 selections from a larger collection from the Mediterranean Region of Turkey. Several pomological characteristics of the genotypes were determined on 5-year-old trees during the 2001 and 2002 growing season. Averaged over the 2 years, fruit weight ranged between 22 and 52 g, total soluble solids content (TSS) ranged between 20.1 and 27.4%, and acidity ranged between 0.09 and 0.26%. ‘Bursa Siyahi’, ‘Goklop’, 31-IN-17, 31-IN-11 and 31-IN-09 produced the largest fruits in terms of fruit weight and dimensions. 31-IN-01, 31-IN-02, ‘Yesilguz’, ‘Morguz’ and ‘Ufak Yesil’ had the highest TSS. ‘Yediveren’, ‘Goklop’, ‘Bursa Siyahi’ and 31-IN-16 scored the highest in overall quality according to the weighted ranked method. Based on the results obtained ‘Yediveren’, ‘Goklop’ and 31-IN-16 could be alternatives to ‘Bursa Siyahi’, currently the most favored fresh table fig cultivar. These alternatives appear to have potential for both local consumption and export markets. Our results also indicate extensive diversity among Turkish figs permitting marketing of a broad range of fresh fig traits.  相似文献   
398.
Journal of Plant Diseases and Protection - Chickpea Ascochyta blight caused by Didymella rabiei is one of the most important fungal diseases affecting yield and seed quality negatively in Turkey....  相似文献   
399.
This study was conducted to evaluate the roles of glycine betaine (GB) in mitigating deleterious effect of salt stress on lettuce. Lettuce plants were subjected to two salinity (0 and 100 mmol l?1 NaCl) and four GB levels (0, 5, 10, 25 mmol l?1). Salinity resulted in a remarkable decrease in growth parameters, relative leaf water content and stomatal conductance. Plants subjected to salt stress exhibited an increase in membrane permeability (MP), lipid peroxidation (MDA), leaf chlorophyll reading value, H2O2 and sugar content. Exogenous foliar applications of GB reduced MP, MDA and H2O2 content in salt-stressed lettuce plants. Salt stress increased Na and generally decreased other nutrient elements. GB reduced Na accumulation, but significantly increased other element contents under salinity conditions. The study showed that gibberellic acid (GA) and salicylic acid (SA) content in salt-stressed plants were lower than those of nonstressed plants. However, salinity conditions generally increased the abscisic acid content. GB treatments elevated the concentrations of GA, SA and indole acetic acid (IAA) at especially 10 and 25 mmol l?1 GB under salt stress conditions. It could be concluded that exogenous GB applications could ameliorate the harmful effects of salt stress in lettuce.  相似文献   
400.
Abstract

This study was carried out to evaluate the effect of long-term natural aging on germinability and several biochemical characteristics regarding antioxidative response of both dry and germinating two different clover (Trifolium repens and Trifolium pratense) seeds stored for 40 years. The percent germination of the seeds was monitored for 7 days. The activities of catalase, peroxidase, superoxide dismutase, lipid peroxidation, H2O2 levels, and phenolic matter content were tested on 0, 1st, 3rd, and 7th days of germination. On the 7th day of germination, the germination ratios of the old T. repens and T. pratense seeds were 32 and 17%, while freshly harvested seeds showed 99 and 96% germination on the 4th day, respectively. The long-term aging caused an important increase in lipid peroxidation levels of the old dry seeds. Total phenolic content was high in the old dry seeds of T. repens compared with those of T. pratense. Remarkably, the long-term aging caused an important decrease in H2O2 content and the activities of catalase and peroxidase enzymes, but an increase in activity of superoxide dismutase in both the old dry seeds. The decreases in germinability of the old legume seeds were well correlated with the increasing level of lipid peroxidation and the decreasing activities of peroxidase and catalase. During the germination of the legume seeds, a noticeable increase was determined only in peroxidase activity in two types of the old seeds, while catalase activity decreased. However, the other biochemical parameters studied did not significantly change between the germinating old seeds and their freshly harvested controls.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号