全文获取类型
收费全文 | 205篇 |
免费 | 12篇 |
专业分类
林业 | 13篇 |
农学 | 11篇 |
基础科学 | 1篇 |
56篇 | |
综合类 | 8篇 |
农作物 | 49篇 |
水产渔业 | 25篇 |
畜牧兽医 | 40篇 |
园艺 | 4篇 |
植物保护 | 10篇 |
出版年
2022年 | 11篇 |
2021年 | 15篇 |
2020年 | 12篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 22篇 |
2016年 | 21篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 26篇 |
2012年 | 14篇 |
2011年 | 17篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 15篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2000年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
排序方式: 共有217条查询结果,搜索用时 15 毫秒
141.
142.
In this study, the efficiency of chitin and chitosan toward the removal of ethylbenzene from aqueous solutions was investigated. Batch adsorption experiments of ethylbenzene-contaminated waters (5?C200 mg/L) were carried out to evaluate the removal performance. Ethylbenzene uptake was determined from the changes in concentration, as the residual concentration was measured by gas chromatography with mass spectroscopy. The results indicated that the adsorption of ethylbenzene by chitin and chitosan were in agreement with the Langmuir isotherm, for two parameters model, and Redlich?CPeterson isotherm, for three parameters model. A maximum removal percentage of 65% of ethylbenzene can be achieved using chitosan as adsorbent material. The adsorption capacity of ethylbenzene followed the order chitosan?>?chitin. The pseudo-second order rate model described best the adsorption kinetics of ethylbenzene for the two selected adsorbents. The kinetic studies also revealed that the pore diffusion is not the only rate controlling step in the removal of ethylbenzene. Overall, the study demonstrated that chitosan is a potential adsorbent for the removal of ethylbenzene at concentrations as high as 200 mg/L. 相似文献
143.
Mathematical models employing textural data are commonly used for the estimation of the particle-size distribution (PSD) curve. In this study, two models were used: (1) the model proposed by Fredlund et al. (2000) (F model), and (2) the model proposed by Skaggs et al. (2001) later modified by Fooladmand and Sepaskhah (2006) (FS model). Comparison of the results obtained by these two models, applied for 30 soils from the south of Iran, showed that the F model was better when the model parameters were determined by setting minimum differences between the measured and estimated PSD curve. Also, three equations based on soil textural data were derived for estimating parameters of the F model, and these equations were used to estimate the PSD curve. The results showed that for 10 independent soils from the south of Iran and 50 soils from the UNSODA database, the FS model was better than the F model based on three new derived equations. Therefore, the FS model can be safely used to estimate the PSD curve with different soil textures; however, the F model is appropriate for representation of the measured PSD curve. 相似文献
144.
In this study, the effects of penconazole (PEN) and calcium (Ca) on growth amelioration and quality of seed oil in canola (Brassica napus L.) under drought stress were investigated. Drought stress reduced the growth parameters (fresh weight and dry weight) in canola; however the application of PEN and Ca improved these parameters under drought condition. Inducing effect of Ca on protein content was more prominent than PEN. Proline content increased under drought stress and PEN and Ca treatment caused more induction it under drought. PEN and Ca alleviated the negative effects of drought stress in canola by inducing antioxidant defense. The application of PEN and Ca caused a significant reduction in lipid peroxidation and hydrogen peroxide and mitigation of the drought induced oxidative stress. Drought stress induced protein content, total phenol, flavonol content, soluble sugar, palmitic acid and palmitoloic acid, and reduced flavonoid content, oleic acid, linolenic acid, and linolonoic acid in canola seed. PEN and Ca increased palmitic acid, linoleic acid (Omega-6), linolenic acid (Omega-3), oleic acid, protein, and soluble sugar. Our results indicated that application of PEN and Ca enables canola plants to withstand the deleterious impact of drought stress and caused improvement of antioxidant capacity, essential fatty acids (linolenic acid and linolonoic acid) and oil quality in canola seed. 相似文献
145.
Maryam Khosravi Hafshejani Chimezie Jason Ogugbue Norhashimah Morad 《Water, air, and soil pollution》2013,224(9):1-16
A novel dye degrading bacterium capable of decolorizing and mineralizing four different dyes (Methyl red, Orange II, Direct red 80, and Direct blue 71) was isolated from textile industrial wastewater using the selective enrichment technique. The bacterium was identified as Pseudomonas aeruginosa. More than 80 % decolorization of Direct red 80 was obtained under microaerophilic conditions in 48 h, whereas only 10 % color removal was obtained under oxic conditions at the same time. Subsequent aeration of the decolorized medium resulted in the mineralization of the metabolic intermediates generated after azo bond cleavage by P. aeruginosa as confirmed by total organic carbon content and high-performance liquid chromatography analyses. The degradation products were characterized by Fourier transform infrared spectrometer and nuclear magnetic resonance techniques whereas the biotoxicity profile of the samples were evaluated using the brine shrimp lethality test assay. Data from this study provide evidence of dye mineralization and detoxification by a monoculture of P. aeruginosa in successive microaerophilic/oxic stages. 相似文献
146.
Abdulsattar Darabi Shahram Omidvari Alireza Shafiezargar Mohammadreza Rafie Maryam Javadzadeh 《Journal of plant nutrition》2013,36(19):2482-2494
AbstractThe aim of this study was to investigate the influence of different compositions of nitrogen (N) sources on yield and nutritional quality in potato cultivars (Solanum tuberosum L.). The experiment used a factorial arrangement as two factors in randomized complete block design. Factor (A) was nitrogen sources: control, 75% M?+?25%V, 50% M?+?50%V, 100% M, where M plots received nitrogen from mineral fertilizer and V plots received nitrogen from vermicompost. Factor (B) was potato cultivars (Sante and Savalan). In Sante cultivar, 75% M?+?25%V produced the highest total and marketable yield. In Savalan, cultivar application of vermicompost in 75% M?+?25%V and 50% M?+?50%V increased significantly total and marketable yield as compared with 100% M. Application of vermicompost significantly decreases tuber nitrate content and increases nitrogen-use efficiency. In Savalan, cultivar 50% V?+?50%M and in Sante cultivar 75% V?+?25%M can effectively be used for improving yield and nutritional quality of tuber. 相似文献
147.
Mojtaba Raeisi Mohammad Hashemi Majid Aminzare Fatemeh Ghorbani Bidkorpeh Maryam Ebrahimi Behrooz Jannat 《Journal Of Aquatic Food Product Technology》2020,29(3):253-263
ABSTRACTMeat products, such as fish meat, are known to be susceptible to undesirable chemical and microbial reactions that characterize spoilage. In this study, the effect of a sodium alginate and chitosan coating incorporated with Mentha piperita, Artemisia dracunculus, and Zataria multiflora essential oils on chemical and microbial attributes of rainbow trout meat was evaluated during storage at 4°C. Chemical and microbial assays were performed on rainbow trout fillets with alginate and chitosan coatings and 0.2% concentration of test essential oils. The results showed that the alginate coating with essential oils significantly decreased production of thiobarbituric acid (TBA) and total volatile basic nitrogen (TVBN) and reduced the growth of foodborne spoilage bacteria during storage at 4ºC. At day 12, the best results were obtained in chitosan coating + Z. multiflora, with 5.96 ± 0.12, 4.93 ± 0.12, and 3.83 ± 0.2 for total viable counts, psychrotrophic bacterial count, and lactic acid bacteria count, respectively. Moreover, the lowest amounts of chemical analysis were observed in chitosan coating + Z. multiflora at the final day (0.54 ± 0.03 and 20.31 ± 0.1 for TBA and TVBN, respectively). Our study revealed that essential oils can be used as effective natural components against undesirable chemical and microbial reactions in fish meat. 相似文献
148.
149.
Moritomo Y Shimojo K Miyadera K Khalaj M Asano Y Kunieda T Ogawa H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(3):293-296
A coagulopathy with subcutaneous bleeding and muscular or peritracheal/periesophageal bleeding occurred in two male Japanese Brown calves of the same dam. One of the affected calves died three days after the onset of bleeding and the other survived normally until being slaughtered despite once suffering from subcutaneous hematoma. Hemostatic tests of the latter case showed prolonged activated partial thromboplastin time (APTT), and severely reduced factor VIII activity. In addition, von Willebrand factor activity, determined by the human platelet aggregation test, was within the normal range; therefore, the calf was diagnosed with hemophilia A. These are the first bovine cases of hemophilia A definitely diagnosed clinicopathologically. 相似文献
150.
Saeed Khazaie Mahvash Jafari Javad Heydari Alireza Asgari Kavoos Tahmasebi Maryam Salehi Mohammad Saleh Abedini 《Journal of animal physiology and animal nutrition》2019,103(5):1619-1628
Diazinon (DZN) as an organophosphate pesticide may cause oxidative stress in different tissues. Antioxidants increase tissue protection from oxidative stress. The aim of the present study was to investigate prophylactic and therapeutic effects of vitamin C against oxidative stress caused by DZN in various tissues of male Wistar rats. Thirty rats were divided into five groups: control group received corn oil as DZN solvent, DZN group received 100 mg/kg of DZN, C group received 200 mg/kg of vitamin C, C‐DZN and DZN‐C groups received vitamin C before and after DZN injection. Plasma and various tissues were prepared and evaluated for measurement of the biochemical parameters and oxidative stress biomarkers. Results showed that acute administration of DZN significantly increased superoxide dismutase and glutathione‐S‐transferase activities and malondialdehyde level in all tissues, catalase (CAT) activity in liver, kidney and heart and some plasma biochemical indices, while it decreased cholinesterase and lactate dehydrogenase activities and glutathione content in all tissues. CAT activity in erythrocytes, brain and spleen was decreased in DZN‐exposed rats compared with the control group. Administration of vitamins C in both prophylactic and therapeutic groups ameliorated in these parameters, although all these tests in tissues did not return to the normal level. These data suggest that oxidative stress is an essential mechanism involved in DZN‐induced adversity effect, as evidenced by the altered activity of antioxidant enzymes, depleted GSH content and the enhanced membrane lipid peroxidation. Both the prophylactic and therapeutic treatments of rats to vitamin C have beneficial effects against oxidative stress and cholinergic hyperactivity induced by DZN in tissues especially in the brain tissue through free radical scavenging. 相似文献