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1.
抗生素在环境中的转归及其生态毒性   总被引:50,自引:2,他引:48       下载免费PDF全文
王冉  刘铁铮  王恬 《生态学报》2006,26(1):265-270
抗生索被长期大量地用于人和动物的疾病治疗,并以亚治疗剂量添加于动物饲料长期用于动物疾病的预防和促进生长,大部分抗生紊不能完全被机体吸收,而有高达85%以上抗生素以原形或代谢物形式经由病人和畜禽粪尿排人环境,经不同途径对土壤和水体造成污染。最近研究显示在城市废水和表面水中检测到了抗生索的存在。但关于抗生素在环境中的分布、迁移和稳定性等的研究资料很少。环境中的抗生素会对环境生态系统包括细菌、水生生物、土壤生物和植物等产生危害,并产生大量耐药菌,对人类健康构成威胁。为评估抗生素在环境中潜在的危害,就抗生素在环境中的分布、转归及对环境和人的危害等方面进行综述,并对今后的研究方向作了探索。  相似文献
2.
Development and mapping of microsatellite (SSR) markers in wheat   总被引:41,自引:9,他引:32  
Microsatellite DNA markers are consistently found to be more informative than other classes of markers in hexaploid wheat. The objectives of this research were to develop new primers flanking wheat microsatellites and to position the associated loci on the wheat genome map by genetic linkage mapping in the ITMI W7984 × Opata85 recombinant inbred line (RIL) population and/or by physical mapping with cytogenetic stocks. We observed that the efficiency of marker development could be increased in wheat by creating libraries from sheared rather than enzyme-digested DNA fragments for microsatellite screening, by focusing on microsatellites with the [ATT/TAA]n motif, and by adding an untemplated G-C clamp to the 5-end of primers. A total of 540 microsatellite-flanking primer pairs were developed, tested, and annotated from random genomic libraries. Primer pairs and associated loci were assigned identifiers prefixed with BARC (the acronym for the USDA-ARS Beltsville Agricultural Research Center) or Xbarc, respectively. A subset of 315 primer sets was used to map 347 loci. One hundred and twenty-five loci were localized by physical mapping alone. Of the 222 loci mapped with the ITMI population, 126 were also physically mapped. Considering all mapped loci, 126, 125, and 96 mapped to the A, B, and D genomes, respectively. Twenty-three of the new loci were positioned in gaps larger than 10 cM in the map based on pre-existing markers, and 14 mapped to the ends of chromosomes. The length of the linkage map was extended by 80.7 cM. Map positions were consistent for 111 of the 126 loci positioned by both genetic and physical mapping. The majority of the 15 discrepancies between genetic and physical mapping involved chromosome group 5.Electronic Supplementary Material Supplementary material is available for this article at  相似文献
3.
红壤坡地柑桔园栽植香根草的生态效应   总被引:37,自引:2,他引:35       下载免费PDF全文
4.
高温对杂交水稻籽粒灌浆和剑叶某些生理特性的影响   总被引:25,自引:0,他引:25  
以杂交籼稻特优559为材料,探讨了高温胁迫对水稻灌浆期剑叶中有关生理特性和籽粒灌浆速率的影响.结果表明:高温胁迫加速了剑叶叶绿素的丧失,使SOD活性明显降低,质膜透性和MDA含量明显增加,脯氨酸、AsA、GSH、可溶性蛋白质以及可溶性糖含量明显降低,籽粒灌浆速率和籽粒重下降.高温使灌浆期水稻叶片衰老加速、光合能力下降是其导致灌浆速率、结实率、粒重和籽粒产量降低的主要生理原因.  相似文献
5.
 The discovery of wide-compatibility varieties (WCVs) that are able to produce normal fertility hybrids when crossed both to indica and japonica rice has enabled the fertility barrier between indica and japonica subspecies to be broken and provided the possibility of developing inter-subspecific hybrids in rice breeding programs. However, a considerable variation in the fertility level of hybrids from the same WCV crossed to different varieties has often been observed. One hypothesis for this variable fertility is that additional genes are involved in hybrid fertility besides the wide-compatibility gene (WCG). To assess such a possibility, we performed a genome-wide analysis by assaying a large population from a three-way cross ‘02428’/‘Nanjing 11’//‘Balilla’ using a total of 171 RFLP probes detecting 191 polymorphic loci distributed throughout the entire rice linkage map. Our analysis recovered 3 loci conferring significant effects on hybrid fertility. The major locus on chromosome 6 coincided in chromosomal location with the previously identified S 5 locus, and the 2 minor loci that mapped to chromosomes 2 and 12, respectively, were apparently distinct from all previously reported hybrid sterility genes. Interaction between the indica and japonica alleles at each of the loci caused a reduction in hybrid fertility. The joint effect of the 2 minor loci could lead to partial sterility even in the presence of the WCG. The location of the S 5 locus on the molecular marker linkage map was determined to be approximately 1.0 cM from the RFLP locus R2349. This tight linkage will be useful for marker-aided transfer of the WCG in hybrid rice breeding and for map-based cloning. Received: 5 February 1997 / Accepted: 4 April 1997  相似文献
6.
迁飞过程中昆虫的行为:对风温场的适应与选择   总被引:24,自引:1,他引:23       下载免费PDF全文
翟保平  张孝羲 《生态学报》1993,13(4):356-363
本文综述了昆虫在迁飞过程中对大气物理环境的各种行为反应,有边界层气象的理论重新审视迁飞种群的时空分布,提出了“边界层顶现象”的概念。即边界层顶的低空逆温和低空急流为迁飞种群提供了最适宜的风温场,迁飞种群在边界层顶集聚成层,并通过定向理一步修饰其位移方位,表现出对风温场的主动选择能力和对大气结构和运动的高度复杂的适应性反应。进一步深化对“边界层顶现象”的认识,对迁飞性害虫的异地预测具有重要的理论意义  相似文献
7.
中国悬钩子属植物的利用价值概述   总被引:22,自引:1,他引:21       下载免费PDF全文
主要报道中国悬钩子属植物作为果树种质资源和药用植物的利用价值及果实色素和香味成分的利用潜力。经过十余年的调查1引种栽培和观测评价,发现一些种类可以作为野生小果类果树直接利用,其中23种4变种是悬钩子类果树选育种的优良种质。据文献记载和民间调查发现。45种4变种悬钩子植物可以作为中草药治疗多种疾病。对灰白毛莓、高梁泡、蓬、掌叶复盆子和黑莓果实色素的研究结果表明:悬钩子果实色素以醇提法为佳,水提法效果  相似文献
8.
Flooding effects on membrane permeability, lipid peroxidation and activated oxygen metabolism in corn (Zea mays L.) leaves were investigated to determine if activated oxygens are involved in corn flooding-injury. Potted corn plants were flooded at the 4-leaf stage in a controlled environment. A 7-day flooding treatment resulted in a significant increase in chlorophyll breakdown, lipid peroxidation (malondialdehye content), membrane permeability, and the production of superoxide (O 2 - ) and hydrogen peroxide (H2O2) in corn leaves. The effects were much greater in older leaves than in younger ones. Spraying leaves with 8-hydroxyquinoline (an O 2 - scavenger) and sodium benzoate (an .OH scavenger) reduced the oxidative damage and enhanced superoxide dismutase (SOD) activity. A short duration flooding treatment elevated the activities of SOD, catalase, ascorbate peroxidase (AP), and glutathione reductase (GR), while further flooding significantly reduced the enzyme activities but enhanced the concentrations of ascorbic acid and reduced form glutathione (GSH). It was noted that the decline in SOD activity was greater than that in H2O2 scavengers (AP and GR). The results suggested that O 2 - induced lipid peroxidation and membrane damage, and that excessive accumulation of O 2 - is due to the reduced activity of SOD under flooding stress.  相似文献
9.
云南悬钩子种质资源考察   总被引:16,自引:0,他引:16       下载免费PDF全文
1996 ̄1997年进行了云南省悬钩子资源考察。野外调查发现1个新种、5个新种、新分布6种5变种。结合前人采集记载,云南省悬钩子植物种类为中107种45变种,其中云南特有种30种16变种,西南4省特有种28种10变种,合计特有种共58种26变种顺滇南、滇东南、滇中、滇西和滇东并5个调查地区中,悬钩子属植物最集中分布在滇西和滇东南。阐述了物种分布特点及变异的多样性。介绍了栽秧泡(Rubus ellp  相似文献
10.
植物重金属镉(Cd2+)吸收、运输、积累及耐性机理研究进展   总被引:15,自引:0,他引:15  
仇硕  张敏  孙延东  黄苏珍 《西北植物学报》2006,26(12):2615-2621
本文从植物对Cd2 吸收、运输及积累机制,以及Cd2 对植物的伤害、植物对Cd2 的耐性机制等三个层面对相关研究进展进行了综述,并对该研究领域的重点问题进行了展望。  相似文献
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