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51.
水杨酸和壳聚糖对NaCl胁迫下黄瓜种子萌发的促进作用 总被引:2,自引:1,他引:1
以黄瓜津优1号为试材,采用0.1mmol·L-1水杨酸(SA)、50mg·L-1壳聚糖(CTS)溶液浸种,测定了100mmol·L-1NaCl胁迫下黄瓜种子发芽势、发芽率及α-淀粉酶、脱氢酶、磷酸酶活性等指标。NaCl胁迫下,黄瓜种子萌发受到明显抑制,发芽势、发芽率分别比清水对照降低31.3、25.6个百分点;SA、CTS单一或共同浸种处理提高了NaCl胁迫下黄瓜种子发芽率及相关酶活性,且SA、CTS共同浸种的效果优于SA、CTS单一处理,发芽率比NaCl胁迫处理增加19.2个百分点,α-淀粉酶、脱氢酶、磷酸磷活性分别比NaCl胁迫处理增加24.7%、16.2%、24.1%。说明SA、CTS对NaCl胁迫下黄瓜种子萌发具有明显的促进作用,且两者呈协同效应。 相似文献
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以从家蚕蛹壳中提取的壳聚糖为主要原料,与明胶共混溶解后加入助剂,通过冷冻真空干燥法制备海绵状复合止血材料。采用L16(45)正交试验,探讨复合止血材料中蚕蛹壳聚糖、明胶以及戊二醛、氯化钙和甘油等助剂的含量对体外凝血指数(BCI)的影响。各因素对BCI的影响大小顺序是:蚕蛹壳聚糖>氯化钙>戊二醛>明胶>甘油。优化复合止血材料中各组分的质量分数为:蚕蛹壳聚糖2.5%,明胶3.0%,戊二醛0.005%,氯化钙0.1%,甘油0.05%。对该复合止血材料进行体外凝血测试,并制作家兔耳动脉出血模型进行活体止血效果的试验,结果均表明其具有良好的止血效果,体外凝血指数较医用纱布和明胶海绵极显著下降,对缩短家兔耳动脉止血时间和降低出血量均极显著优于医用纱布和明胶海绵。 相似文献
54.
Sung Soo Han 《Fibers and Polymers》2005,6(3):219-223
Water-soluble chitin (WSC) was prepared by carefully deacetylating chitins to about 50% of N-acetyl content. Topical formulations
based on WSC were prepared and their effects on wound healing were evaluated on a rabbit ear model. Full-thickness, open skin
wounds were made on the ears of rabbits and WSC ointments were embedded in the open wounds. The application of WSC ointments
significantly accelerated wound healing and wound contraction. The areas of epithelialization and granulation tissues in WSC
ointment group are remarkably larger than those in control group (no treatment) and in placebo group (treated with ointment-base
materials). A large number of grown granulation tissues including dense fibroblast deposition were observed under the thickened
epithelium of the wound treated with WSC ointments. The number of inflammatory cells in WSC ointment group was significantly
decreased compared with those in control and placebo groups, indicating that WSC would give low stimuli to wounds and prevent
excessive scar formation. Neovascularization was the most prominent in WSC ointment group. Wound contraction in WSC ointment
group was much larger than those in control and placebo groups. Overall results demonstrate that the topical formulation based
on WSC is considered to become an excellent dressing as a wound healing assistant. 相似文献
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Semi-interpenetrating polymeric network (semi-IPN) hydrogels based on poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(2-hydroxyethyl
methacrylate-co-sodium methacrylate) [P(HEMA-co-SMA)], and chitosan with different molecular weights were prepared by crosslinking
with ethylene glycol dimethacrylate (EGDMA) and poly(ethylene glycol) diacrylate (PEGDA) and their gelation time, water content,
mechanical properties, and morphology were investigated. In consideration of the influence of the molecular weight of chitosan,
there is no big difference in the water content, while tensile properties and compressive modulus increased as the molecular
weight of chitosan increased. The water content increased and tensile properties and compressive modulus decreased with increasing
SMA concentration. Considering the effect of the crosslinking agent, PEGDA had higher water content and lower tensile and
compressive moduli than EGDMA. It is suggested that PHEMA/chitosan and P(HEMA-co-SMA)/chitosan semi-IPN hydrogels with different
structures and physical properties can be prepared depending on the molecular weight of chitosan, the copolymerization with
SMA, and the crosslinking agent type. 相似文献
58.
Study of antimicrobial activity of aloevera, chitosan, and curcumin on cotton, wool, and rabbit hair 总被引:1,自引:0,他引:1
Aloevera, chitosan, and curcumin were applied in alone and in combination with each others on cotton, wool and rabbit hair
by exhaustion method for the assessment of their antimicrobial activity. The antimicrobial activity of these natural ingredients
was better in peroxide treated cotton, formic acid treated wool/rabbit hair fibrous substrates than their corresponding intact
ones. Aloevera shown better antimicrobial activity than chitosan and curcumin when applied alone and its antimicrobial activity
was enhanced by addition of both chitosan and curcumin. The application of aloevera+chitosan+curcumin combination on peroxide
treated cotton and formic acid treated wool/rabbit hair fibrous substrate was fast up to twenty five washing cycles. 相似文献
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60.
鸡志贺氏菌产超广谱β内酰胺酶(ESBLs)的分子进化 总被引:2,自引:0,他引:2
【目的】检测鸡志贺氏菌分离株和诱导株所产ESBLs的基因型,探讨其产酶耐药的分子进化机制。【方法】对1株诱导和5株临床分离产ESBLs细菌分别用TEM、SHV、CTX-M 3种通用引物进行PCR扩增、基因克隆及测序分析,确定鸡福氏志贺氏菌ESBLs的基因型和基因亚型。【结果】5株临床福氏志贺氏菌质粒上具有相同的TEM序列和相同的SHV序列,TEM型序列与AY903309(TEM-116)序列相比发生了2个位点基因突变即G157A、C409T,其中409位点碱基突变为沉默突变,157位点碱基突变导致相应氨基酸序列53位发生突变Gly53Ser,此氨基酸突变为新的突变位点,所以该TEM型ESBLs是一种新的TEM亚型,暂命名为TEM-1V型;SHV型与AY826418(SHV-12)序列完全相同,为SHV-12型。头孢噻呋诱导标准福氏志贺氏菌,诱导10代时产生了TEM-1型β-内酰胺酶,诱导50代时产生了TEM-1V型ESBLs。【结论】临床分离鸡福氏志贺氏菌ESBLs的基因型为TEM-1V型和SHV-12型,鸡福氏志贺氏菌TEM-1V型ESBLs是由 TEM-1型β内酰胺酶直接进化而来。 相似文献