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1.
Nanoscale zero-valent iron particles (nZVIs) have been used as the stabilizing materials for remediation of heavy metals (HMs). The usage of nZVIs in the presence of oxygen is a challenging task. When this material comes in contact to air, immediately oxide formation takes place. Thus, preparation of air-stable nZVIs is necessary for successful remediation process. Therefore, the present study has attempted to evaluate the effects of three kinds of synthesized nZVIs, including nZVIEDTA (stabilized by ethylenediaminetetraacetic acid), nZVIDTPA (stabilized by diethylenetriamine pentacetic acid) and nZVI (without chelating agent), to determine their ability to stabilize lead (Pb) in two Pb-spiked soils. Pb-spiked soils were separately incubated with additives at the rates of 0.5% and 2% (W/W) for 90 days. The efficacy of nZVIs was evaluated by desorption kinetic and chemical fractionation experiments. According to the results, addition of nZVIEDTA, nZVIDTPA and nZVI significantly decreased Pb release by 70.1–86.4%, 56.5–70.6% and 24.3–49.2%, respectively. Among the three kinds of nZVIs, nZVIEDTA was the most effective treatment in decreasing desorption and mobility factor of Pb. In practice, all three kinds of nZVIs are effective in Pb immobilization, while application of nZVIEDTA at the rate of 2% was the best treatment to immobilize Pb in polluted soils.  相似文献   
2.
To investigate the influence of grape-pruning-residue (GPR) biochar on cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) immobilization in a contaminated soil, a laboratory study was conducted with different rates of GPR biochar (0, 2, 5 and 10% w/w) at 25°C. After 1, 2, 4, and 8 weeks of incubation, the Tessier sequential extraction procedure was performed and metal mobility factor (MF) and metal stability index (IR) were calculated. The exchangeable (EX) and carbonate (CAR) fractions of the metals decreased significantly (p ≤ 0.05) with the biochar addition. The EX metal fractions decreased by 23 to 72%, and the CAR fractions decreased by 51 to 67% in the 10% biochar treatment after 8-week incubation. The MF values of Cd, Pb, Cu and Zn decreased by 47, 62, 70 and 49%, respectively, with addition %10 of the biochar. Biochar addition favored the metal redistribution into more stable fractions and resulted in an increase in IR values. The results demonstrated that the GPR biochar, especially at high application rate (10%), can effectively immobilize the heavy metals, thereby reducing their mobility in contaminated soils.  相似文献   
3.
分别用海藻酸钠、聚乙烯醇、卡拉胶、明胶、醋酸纤维素和聚丙烯酰胺作载体,对食用菌菌种进行固定化实验,结果显示以10%聚乙烯醇添加0.8%海藻酸钠为包埋剂进行菌种固定化,所制备的固定化菌种其机械强度和细胞活性都最好。  相似文献   
4.
A laboratory study was conducted at the Indian Agricultural Research Institute, New Delhi on a sandy clay loam soil of pH 7.9 and organic C content of 0.34% to study the effect of incorporating Sesbania or Vigna legume residues or wheat straw at 15 and 30t ha?1 on temporal variation in ammoniacal and nitrate‐N in soil under submergence and well drained conditions. Under submergence most mineral N was present as ammoniacal‐N, while under well drained conditions it was present as Nitrate‐N. The content of ammoniacal N in soil was the highest after 30 days of incubation and declined thereafter under submergence. On the other hand under well drained conditions the mineral‐N (mostly nitrate) content in soil at 30 DAI was very little and showed increases only later, reaching the highest level at 90 DAI. Application of wheat straw specially at 301 ha?1 level resulted in immobilization of native soil‐N. These results show that rice which is grown under submergence can be transplanted soon after incorporation of legume residues, but for wheat or other crops which are grown under well drained condition a time interval of 30 days or more needs to be provided before sowing the crop.  相似文献   
5.
以海藻酸钙为载体包埋唾液链球菌嗜热亚种Y-2的菌体细胞,对固定化细胞催化合成γ-氨基丁酸进行了较详细的研究。研究结果表明:固定化细胞谷氨酸脱羧酶(Glutamate decarboxylase,GAD)反应的最适温度为40℃,同时具有良好的温度稳定性。固定化细胞酶活最适反应pH为3.8。细胞经固定化后pH稳定性明显增加,GAD酶活回收率普遍高于游离细胞。0.1%Triton X-100具有较强的酶活促进作用。固定化细胞的GAD在酶促反应中并不存在底物抑制现象。在上述最优条件下进行菌体生产力测试,固定化细胞转化L-谷氨酸单钠盐11 h后,转化液γ-氨基丁酸的浓度达到了2.79 g/L。  相似文献   
6.
改进的聚乙烯醇固定化方法对废水产氢的影响   总被引:1,自引:0,他引:1  
施娟娟  黄兵  陈丽琼 《江西农业学报》2010,22(2):126-128,132
对传统的PVA-H3BO3固定化方法进行改进,以球径变化率和累积产氢量为主要考察指标,并通过扫描电镜分析改进前后凝胶内部结构的变化,最终确定聚乙烯醇固定化微生物产氢的最佳方法。  相似文献   
7.
Three wine-making residues (grape seeds, skins and stems), and corn cobs were evaluated as support material for immobilization of Saccharomyces cerevisiae and the ethanol production by the immobilized cells was assessed. The main objective of this study was to find an abundant and low cost material suitable for the cells immobilization and able to be used in a next step of wine production by immobilized yeast cells. The four natural materials were used as support in two different forms: untreated, and treated by a sequence of acid and basic reactions. Untreated grape skin and corn cobs provided the highest cell immobilization results (25.1 and 22.2 mg cells/g support, respectively). The maximum ethanol production yield (about 0.50 g/g) was also obtained when the cells were immobilized in these untreated materials. It was also found that the support materials released nutrients to the medium, which favored the yeast development and the ethanol production. The use of immobilized cells systems under agitated conditions gave ethanol yields similar to those obtained by the static fermentations, but the immobilized cell concentration was significantly lower. In brief, static fermentation with cells immobilized on grape skins or corn cobs appear to be an interesting alternative for use on wine-making. The use of grape skins, particularly, which is a by-product of the wine elaboration, could be of larger interest to obtain an integrated wine production process with by-product reuse.  相似文献   
8.
微生物降解水体中硝基苯的研究进展   总被引:1,自引:0,他引:1  
从降解菌的种类、降解途径和机理、培养基优化、固定化和趋化性角度,介绍了生物降解硝基苯的最新研究进展。  相似文献   
9.
To determine whether olive flounder (Paralichthys olivaceus) immunized with lysate of Philasterides dicentrarchi could be protected immobilization antigen (i-antigen) type independently, fish were immunized with lysate of ciliates obtained from in vitro cultures or ciliates obtained from infected fish. Fish immunized with ciliates obtained from infected fish were completely protected against artificial infection with in vitro cultured P. dicentrarchi, in spite of a weak or no serum agglutination activity against in vitro cultured ciliates. The present results indicate that i-antigen-independent protection was elicited by immunization of fish with the ciliates lysate, and the cultured ciliates would provide a good source for preparation of vaccines, which are cross-protective against various i-antigen types of P. dicentrarchi.  相似文献   
10.
固定化微生物技术在废水处理中的研究与应用   总被引:4,自引:2,他引:2  
固定化微生物技术是一种有效的废水生物处理技术。对微生物固定化方法进行了分类,并对其性能作了比较。综述了固定化微生物方法在各类废水处理中的国内外研究现状,并针对相关问题提出了今后的研究和发展方向。  相似文献   
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