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   277篇
  免费   8篇
  国内免费   33篇
  2023年   10篇
  2022年   5篇
  2021年   4篇
  2020年   9篇
  2019年   3篇
  2018年   7篇
  2017年   7篇
  2016年   7篇
  2015年   13篇
  2014年   8篇
  2013年   22篇
  2012年   6篇
  2011年   5篇
  2010年   7篇
  2009年   4篇
  2008年   9篇
  2007年   14篇
  2006年   10篇
  2005年   6篇
  2004年   11篇
  2003年   13篇
  2002年   6篇
  2001年   8篇
  2000年   11篇
  1999年   2篇
  1998年   7篇
  1997年   9篇
  1996年   5篇
  1995年   5篇
  1994年   7篇
  1993年   8篇
  1992年   2篇
  1991年   6篇
  1990年   11篇
  1989年   2篇
  1988年   3篇
  1987年   4篇
  1986年   3篇
  1985年   9篇
  1984年   7篇
  1983年   2篇
  1982年   10篇
  1981年   1篇
  1980年   5篇
  1979年   1篇
  1976年   1篇
  1974年   2篇
  1970年   1篇
排序方式: 共有318条查询结果,搜索用时 31 毫秒
201.
This report describes the construction of integrated genetic maps in pearl millet involving certain purple phenotype and simple sequence repeat (SSR) markers. These maps provide a direct means of implementing DNA marker-assisted selection and of facilitating "map-based cloning" for engineering novel traits. The purple pigmentation of leaf sheath, midrib and leaf margin was inherited together 'en bloc' under the control of a single dominant locus (the 'midrib complex') and was inseparably associated with the locus governing the purple coloration of the internode. The purple panicle was caused by a single dominant locus. Each of the three characters (purple lamina, purple stigma and purple seed) was governed by two complementary loci. One of the two loci governing purple seed was associated with the SSR locus Xpsmp2090 in linkage group 1, with a linkage value of 22 cM, while the other locus was associated with the SSR locus Xpsmp2270 in linkage group 6, with a linkage value of 23 cM. The locus for purple pigmentation of the midrib complex was either responsible for pigmentation of the panicle in a pleiotropic manner or was linked to it very closely and associated with the SSR locus Xpsmp2086 in linkage group 4, with a suggestive linkage value of 21 cM. A dominant allele at this locus seems to be a prerequisite for the development of purple pigmentation in the lamina, stigma and seed. These findings suggest that the locus for pigmentation of the midrib complex might regulate the basic steps in anthocyanin pigment development by acting as a structural gene while other loci regulate the formation of color in specific plant parts.  相似文献   
202.
不同生态区主要育成谷子品种芽期耐旱性鉴定   总被引:11,自引:1,他引:10  
以-0.5 MPa的PEG6000作渗透介质模拟干旱条件,对不同生态区的谷子(Setaria italica(L.)Beauv.)品种(系)进行种子萌发耐旱鉴定。结果表明:在PEG6000胁迫下,萌发耐旱指数与相对根芽比、芽生长抑制率呈极显著负相关;与根生长抑制率呈正相关,但相关系数小,相关不显著;与相对发芽势呈极显著正相关,且相关系数达0.939,可以反映谷子芽期耐旱性。根据萌发耐旱指数,将201份谷子品种(系)划分为极抗旱、抗旱、中度抗旱、不抗旱和极不抗旱5个等级。  相似文献   
203.
Abstract: In plants, the developmental dynamics of telomere length have only been studied in a few species to date. Contrasting results have been reported. To search for the pattern(s) operating in plants, a study of the telomere length was made in pearl millet. Telomere length in cells representing different developmental stages: a) embryo, b) leaves of 1-week-old seedlings, 1-month-old plants and boot leaf and c) germ cells (pollen) were compared. The presence of the consensus plant telomere repeat sequence (5'-TTTAGGG-3') in pearl millet telomeres was first ascertained; the sensitivity of the sequences hybridizing with (TTTAGGG)4 oligonucleotide to time course Bal 31 exonuclease digestions were studied on dot blots and gel blots. The exonuclease digestion kinetics revealed the presence of the consensus telomere repeat sequence in pearl millet telomeres. The average telomere length (ATL) was measured from autoradiograms of Hae III digested DNA, hybridized with labelled (5'-TTTAGGG-3')4 oligonucleotide using "UVI band" software. No significant difference in the average telomere length was observed between the embryo, leaves of 1-week-old seedlings, boot leaf and pollen. The ATL in leaves of 1-month-old plants was slightly higher. The results of the present investigation and analysis of the reports in the other plants suggest that there is an occasional increase in telomere length in some telomeres but no significant decrease due to loss during DNA replication.  相似文献   
204.
生物炭对不同土壤化学性质、小麦和糜子产量的影响   总被引:37,自引:0,他引:37  
陈心想  何绪生  耿增超  张雯  高海英 《生态学报》2013,33(20):6534-6542
以小麦和糜子为供试作物,利用室外盆栽试验,研究了不同添加量生物炭与矿质肥配施对两种不同土壤化学性质及小麦和糜子产量的影响。生物炭当季用量设5个水平:B0 (0 t/hm2)、B5 (5 t/hm2)、B10 (10 t/hm2)、B15 (15 t/hm2)和B20 (20 t/hm2),氮磷钾肥均作基肥施用。结果表明:1.与对照相比,施用生物炭可以显著增加新积土糜子季土壤pH值,其他处理随生物炭用量的增加虽有增加趋势但差异不显著;显著增加新积土土壤阳离子交换量,增幅为1.5 %—58.2 %;显著增加两种土壤有机碳含量,增幅为31.1 %—272.2 %;2.两种土壤的矿质态氮含量、新积土土壤有效磷和速效钾含量随生物炭用量的增加而显著提高,氮磷钾增幅分别为6.0 %—112.8 %、3.8 %—38.5 %和6.1 %—47.2 %;3.生物炭可显著提高塿土上作物氮吸收量,而作物磷、钾吸收量虽有增加,但差异不显著。生物炭对小麦和糜子的增产效应尚不稳定,在试验最高用量时甚至产生轻微抑制作用。总之,施用生物炭在一定程度上可以改善土壤化学性质,提高土壤有效养分含量,但生物炭对土壤和作物的影响与土壤、作物类型及土壤肥力密切相关。  相似文献   
205.
Seed protein of foxtail and proso millets were fractionated into polypeptides that were analyzed for their major protein, prolamin, and the NH2-terminal amino acid sequences of the proteins were determined. The proteins extracted from foxtail and proso millets were 64.1% and 80.0% prolamin, respectively. The polypeptides of the prolamins were classified into two groups. The major polypeptides of 27-19 kDa were rich in leucine and alanine, whereas the 17-14 kDa polypeptides were rich in methionine and cysteine. Glutelin-like proteins that were extracted with a reducing reagent were high in proline content, the major polypeptides being 17 and 20 kDa. The NH2-terminal amino acid sequence showed that the major polypeptides of prolamin were homologous to α-zein and a glutelin-like protein containing the Pro-Pro-Pro sequence, like the repetitive sequence of γ-zein. Although the prolamin consisted of a similar subunit to that of zein, polypeptides with various pI values were found among them.  相似文献   
206.
Abstract

Wetzel, TH. (Edit.): Symposium mit internationaler Beteiligung zur Schaderregerüberwachung in der industriemäßigen Getreideproduktion. 510 S., Teil I bis III, 134 Abb. Halle: 1975. Reviewed by G. Lutze.

O. V.: Pflanzenschutzmittel-Verzeichnis 1974/1975. 1. Aufl. 121 S. Berlin: VEB Dt. Landwirtschaftsverlag 1975. Reviewed by W. Tarnow.

Schumakov, E. M.; Gussev, G. W.; Fedorintschik, N. S. (Edit.): Biologi?eskie sredstva za??ita rastenij. 25000 Aufl. 408 S., 1. Band, 24 Abb. Moskau: Kolos 1974. Reviewed by Th. Wetzel.

Clifton, C. E. (Edit.): Annual Review of Microbiology. 771 S., 25. Band, zahlreiche Abb. Palo Alto: Annual Reviews Inc. 1971. Reviewed by K. Naumann.

Voronkevi?, I. V.: Vy?ivaemost' fitopatogennych Bakterij v Prirode. 268 S., 16 Abb., 41 Tab., Moskau 1974: Nauka. Reviewed by W. Ficke.

Bel'tjukova, K. I.; Koroleva, I. B.; Muras, V. A.: Bakterial'nye bolezni zernobobovych kultur. 339 S., 57 Abb., 49 Tab. Kiev 1974: Naukova Dumka. Reviewed by W. Ficke.

Pospelov, S. M.; Arsen'eva, M. V.; Grusdev, G. S.: Za??ita rastenij. 487 S. Leningrad 1973: Kolos. Reviewed by W. Ficke.

Noordam, D.: Identification of plant viruses. Methods and experiments. 1. Auflage, 218 S., 134 Abb. Wageningen 1973: Centre for agricultural publishing and documentation. Reviewed by D. Spaar.  相似文献   
207.
Field trials in which seed dressing with Apron Star 42 WS (metalaxyl-M) was tested on five pearl millet cultivars were laid at Gashua (Sahel) and Maiduguri (Sudan Savanna) for three wet seasons (1998–2000). Using the split-plot design, seed dressing and cultivars were tested in main- and sub-plots, respectively. Results showed that at each location and season, there was significantly high seedling emergence and grain yield but lower downy mildew incidence as a result of seed dressing with metalaxyl-M compared with check. Among the cultivars tested, SOSAT C-88 had significantly lower downy mildew incidence and the highest grain yield during the three seasons. Dressed with metalaxyl-M, other cultivars had lower downy mildew and higher grain yield than undressed check. It is therefore important that pearl millet should be dressed with metalaxyl as routine practice before cultivation in the arid area of Nigeria.  相似文献   
208.
The species composition, abundance and plant infestation of stem borers attacking maize and millet were investigated in farmers' fields during the cropping season of 2010 and 2011 in Maiduguri, Nigeria. Stem borers were collected via destructive sampling. In total, three stem borer species (Busseola fusca, Sesamia calamistis and Coniesta ignefusalis) were found, of which S. calamistis (64%) and C. ignefusalis (72%), respectively, were predominant on maize and millet. Across both years, whereas mean plant infestation ranged from 4.8% on millet to 20.8% on maize, mean stem borer abundance ranged from 1.6 individuals on millet to 13.8 individuals on maize. Mean total plant infestation and stem borer abundance varied with different years and both were significantly higher during the 2010 than 2011 cropping season. In spite of the generally low stem borer abundance per farmers' field, plant infestation particularly on maize plants seems to be moderate during different years.  相似文献   
209.
Pearl millet (Pennisetum glaucum L. Br.) is the most important crop in India and Africa. Downy mildew disease of pearl millet caused by the oomycetous fungus Sclerospora graminicola (Sacc.) Schroet., is the major biological constraint in the production of pearl millet. Plasma membrane H+-ATPase is induced in resistant pearl millet against downy mildew pathogen. Sodium orthovanadate, an inhibitor of H+-ATPase, was used in this study to understand its effect on other known defence responses in pearl millet including H+-ATPase. Results suggest that vanadate down-regulates all defence responses tested, such as H+-ATPase (53 ± 5.0%), peroxidase (36 ± 5.6%), phenylalanine ammonia lyase (43 ± 4.5%), β-1,3 glucanase (25 ± 4.2%), lytic activity (32 ± 3.0%), hypersensitive response (57 ± 4.3%) and pathogen colonisation. These data indicate that the plasma membrane H+-ATPase may be a key step in the signaling pathway leading to defence activation in pearl millet against downy mildew disease.  相似文献   
210.
Many domesticated crops are derived from species whose life history includes weedy characteristics, such as the ability to vary branching patterns in response to environmental conditions. However, domesticated crop plants are characterized by less variable plant architecture, as well as by a general reduction in vegetative branching compared to their progenitor species. Here we examine weedy green millet and its domesticate foxtail millet that differ in the number of tillers (basal branches) and axillary branches along each tiller. Branch number in F(2:3) progeny of a cross between the two species varies with genotype, planting density, and other environmental variables, with significant genotype-environment interactions (GEI). This is shown by a complex pattern of reaction norms and by variation in the pattern of significant quantitative trait loci (QTL) amongst trials. Individual and joint analyses of high and low density trials indicate that most QTL have significant GEI. Dominance and epistasis also explain some variation in branching. Likely candidate genes underlying the QTL (based on map position and phenotypic effect) include teosinte branched1 and barren stalk1. Phytochrome B, which has been found to affect response to shading in other plants, explains little or no variation. Much variation in branching is explained by QTL that do not have obvious candidate genes from maize or rice.  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