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   335篇
  免费   0篇
林业   20篇
农学   10篇
基础科学   4篇
  79篇
综合类   9篇
农作物   28篇
水产渔业   33篇
畜牧兽医   91篇
园艺   23篇
植物保护   38篇
  2024年   17篇
  2023年   5篇
  2022年   11篇
  2021年   5篇
  2020年   6篇
  2019年   11篇
  2018年   20篇
  2017年   18篇
  2016年   18篇
  2015年   13篇
  2014年   12篇
  2013年   30篇
  2012年   25篇
  2011年   25篇
  2010年   16篇
  2009年   23篇
  2008年   20篇
  2007年   14篇
  2006年   11篇
  2005年   12篇
  2004年   9篇
  2003年   5篇
  2002年   3篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1993年   2篇
排序方式: 共有335条查询结果,搜索用时 19 毫秒
51.
Microsatellites or Simple Sequence Repeats(SSRs) are informative molecular genetic markers in many crop species. SSRs are PCR-based, highly polymorphic, abundant, widely distributed throughout the genome and inherited in a co-dominant manner in most cases. Here we describe the presence of SSRs in cDNAs of cotton. Thirty one SSR primer pairs of 220 (∼14%) tested led to PCR amplification of discrete fragments using cotton leaf cDNA as template. Sequence analysis showed 25% of 24randomly selected cDNA clones amplified with different SSR primer pairs contained repeat motifs. We further showed that sequences from the SSR-containing cDNAs were conserved across G. barbadense and G. hirsutum, revealing the importance of the SSR markers for comparative mapping of transcribed genes. Data mining for plant SSR-ESTs from the publicly available databases identified SSRs motifs in many plant species,including cotton, in a range of 1.1 to4.8% of the submitted ESTs for a given species. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
52.
In this work, trace metals such as Hg, Pb, As, Cd, Cu, Fe, Mn and Zn in underground water samples obtained from three wells, an ash-pond and drinking water located near the Yatagan Thermal Power Plant were measured. As, Hg, Cu and Zn contents of the underground water were lower than those reported in the EEC (European Economic Community) and WHO (World Health Organization) guidelines. In contrast, the levels of Fe, Pb, Cd and Mn in some groundwater samples were higher than EEC and WHO guideline values. The trace metal concentrations in coal ash-pond water were observed to be lower than water quality standards with the exception of Pb. The obtained results indicated that the trace metal concentration in the sampled drinking water site did not exceed WHO limits.  相似文献   
53.

Apple (Malus domestica Borkh.) is one of the most widely grown and economically important fruit crops in the world. Skin colour is one of the most important criteria for marketing of apple fruits. Thus, improving fruit colouring is one of the main objectives of apple breeding programs. Even though environmental conditions may affect the colouring of apple, understanding the genetic basis of colouring is important to accelerate the breeding process. In recent years, molecular biology and genetic studies were conducted to explore the molecular basis of colouring in apple. Many genes responsible for the anthocyanin synthesis were identified and their associations with colouring of apple fruit flesh and/or skin were demonstrated. In addition, some DNA markers associated with fruit flesh and skin colour have been developed for screening apple cultivars and hybrids. In this study, 90 apple accessions of international, national, and local decents were selected from the genetic resources collection. Genomic DNA was isolated from leaf tissue of all acession and screened with four different DNA markers associated with fruit flesh and skin colour. Apple accessions in the collection were characterized and their genotypes and genetic potential for fruit colouration were determined by different DNA markers. Additionally, the use of these DNA markers in different apple accessions, well-characterized cultivars and uncharacterized local and national types were investigated.

  相似文献   
54.
The aim of this study was to determine the fattening performance and the slaughter and carcass characteristics of Akkeçi (Saanen × Kilis (B1) crossbred) male kids raised in individual crates (IC) or in group pen housing (GP). In both GP and IC groups, total 13 heads of male kids, whose initial body weights were 21.43 ± 1.03 kg and 20.61 ± 0.98 kg, respectively, evaluated for their fattening performances. After 56 days of the fattening period, the final body weights and average daily weight gains of the GP and IC kids were recorded as 30.84 ± 0.82 kg and 25.84 ± 0.76 kg; 182.42 ± 14.77 g and 92.09 ± 13.76 g, respectively (P < 0.001). Adrenal gland weights of the GP and IC groups were similar as 1.66 ± 0.25 g and 1.77 ± 0.22 g, respectively. Although, the carcass conformation of kids was similar between groups, there were significant differences between GP and IC groups for some slaughter and carcass characteristics. In general, although housing kids reared in individual crates provides opportunity to individually feed and monitor a kid, the results obtained from the individual crates in the present study were not satisfactorily from the ethological and production points of view.  相似文献   
55.
In this paper, it was aimed to obtain disposable medical textiles having antibacterial and wound healing properties, as well as biological adaption. For this purpose, the St. John’s Wort oil and flax seed oil were ozonated, and the oils were capsulated with arabic gum. The produced ozonated oils were characterized through FTIR and TGA analyses, as well as the properties of antibacterial, wound healing, and biological adaption were investigated. The produced microcapsules were examined via optical microscope and FTIR. The characterized microcapsules of the ozonated oils were applied to the textiles with padding method. After the applications, the fabrics were researched with SEM and FTIR analyses; in addition the antibacterial and wound healing properties and biological adaption of the textiles were also investigated. The results showed that the St. John’s Wort oil and flax seed oil were successfully ozonated and microcapsulated. The microcapsules of the oils could be applied to the fabric samples with the determined application recipe. The ozonated oils and the fabric samples applied microcapsules of the ozonated oils gained high antibacterial and wound healing property. In addition, the fabric samples were produced as having biological adaptation.  相似文献   
56.
In this study, the adsorption of phosphate on gas concrete from aqueous solutions has been studied as functions of temperature, mixing rates and suspension pH. Over 99% of phosphate removal was found. The chemical composition of the gas concrete has been defined by X-ray analysis. Experimental data was fitted to the Langmuir equation in order to Langmuir coefficients. After calculating Langmuir coefficients, adsorption free energy (Δ G 0 ads.) has been determined. In order to gather information about adsorption mechanism, electrophoretic mobilites of particles were measured at various pHs by using Zeta meter 3.0+. It has been found that the adsorption is driven by the interactions between the ionizations of CaO and Al2O3 and the formation of AlPO4. According to the BET (N2) measurements, the specific surface area of gas concrete was found as 22 m2g-1. The surface area after adsorption has been found as 17 m2g-1. The surface area covered by adsorbate has been found as 5.23 m2g-1 by usingas = ns m. am. NA. These two areas determined by BET and Langmuir model were close to each other (BET: 22 m2g-1–17 m2g-1).  相似文献   
57.
In this study was evaluated potential protective effect of organic selenium (Se) on heavy metal stress induced by lead (Pb) in Cyprinus carpio. For this reason, C. carpio was exposed to sublethal concentration of Pb (1.5 mg/L Pb(NO3)2) for 14 days. The fish were fed a basal (control; measured 0.55 mg/kg Se) diet or a basal diet supplemented with 2.50 mg/kg (measured 2.92 mg/kg Se) organic Se (Sel-Plex®) during the experiment period. The variations in glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) activities, and levels of reduced glutathione (GSH) with malondialdehyde (MDA) in liver and brain tissues of C. carpio were investigated in experimental groups. GSH levels in liver and brain tissues were significantly decreased by exposure to Pb. GST activity was significantly increased (p < 0.05) in liver tissue, but decreased in brain of treated fish by exposure to Pb. Also, GSH-Px activity was significantly increased in liver tissue, but decreased in brain of Pb-treated fish. Levels of MDA were increased in liver and brain of Pb-treated fish. The organic Se treatment for Pb-intoxicated animals improved activities of GSH-Px, GST and levels of MDA within normal limits. Supplemented Se could be able to improve Pb-induced oxidative stress by decreasing lipid peroxidation and regulating antioxidant defense system in tissues.  相似文献   
58.
    
In this study, investigation of some anther structures in Sanguisorba minor Scop. subsp. muricata was aimed. Therefore, anthers were squashed by modified glycerine-gelatine method and additionally different histochemical stainings also were tested. The result illustrated that in different parts of anther, such as marginal, connection tissue, starch and protein granules accumulated. Furthermore, during maturation these deposits were detected in pollen grains also. In addition, a very interesting feature, balloon-like structures filled by proteins, were observed in anther cavity. In the light of these findings, their importance on pollen development was discussed.  相似文献   
59.
60.
Critical concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), and manganese (Mn) with respect to dry matter yield end antagonistic and synergistic relationships among these nutrients were studied in which tomato (Lycopersicon esculentum L.) was grown in recirculating nutrient solution (NFT). Increments of nutrient elements in the nutrient solution increased the proportional rate of the corresponding nutrient elements. Increasing levels of N negatively correlated with plant P and positively correlated with Ca, Fe, and Zn. Iron and Mn contents of the plants were increased and N, K, Ca, and Mg were decreased as a function of P applied. Increases in K in the nutrient solution caused increases in the concentrations of K, N, P, and Zn, and decreases in the concentration of Ca and Fe. Applied Ca increased the concentrations of Ca and N, and decreased the concentrations of P, Mg, Fe, Zn, and Mn. Potassium, Ca, and Fe contents of the plants were decreased and Zn increased, while N, P, and Mn were not affected by the increasing levels of external Mg. Iron suppressed the plant Mg, Zn, and Mn contents. Synergism between Zn and Fe was seen, while P, K, Ca, Mg, and Mn contents were not affected by Zn levels. Potassium, Ca, Mg, and Fe were not responsive to applied Mn, however, N and P contents of the plants were decreased at the highest levels of Mn.  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