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   74篇
  免费   3篇
  国内免费   9篇
  2022年   1篇
  2021年   2篇
  2020年   4篇
  2019年   2篇
  2018年   3篇
  2017年   3篇
  2016年   5篇
  2015年   1篇
  2014年   5篇
  2013年   2篇
  2012年   3篇
  2011年   2篇
  2010年   3篇
  2009年   3篇
  2008年   3篇
  2007年   4篇
  2006年   3篇
  2004年   2篇
  2003年   5篇
  2002年   3篇
  2001年   5篇
  2000年   2篇
  1999年   3篇
  1998年   4篇
  1997年   1篇
  1996年   1篇
  1995年   3篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1985年   1篇
  1984年   1篇
排序方式: 共有86条查询结果,搜索用时 562 毫秒
11.
Monocots and dicots have diverged for 120 million years. The floral morpha of cereals isunique and much different from that of dicot plants. Nevertheless, it has been found that most genes controlling flower development share a conserved sequence called MADS-box[1]. Therefore,it is likely that monocots and dicots could have similar basic characteristics of flower developmentbut the mechanisms of genetic regulation for flowering induction and floral differentiation might be different[2,3]. Du…  相似文献   
12.
许德坚  李强  蒋三元 《蛇志》2009,21(2):103-104
目的观察扶正活血祛瘀法治疗慢性足底溃疡的临床疗效。方法采用四妙勇安汤加减内服,红萝卜加马齿苋煎液浸泡外洗溃疡处,外敷呋喃西林纱布保护伤口的综合治疗方法。结果36例中治愈27例,占75.0%;好转6例,占16.7%;无效3例,占8.3%.姑论以扶正活血祛痰法内服为主,结合红萝卜加马齿苋煎液浸泡外洗与呋喃西林纱布外敷治疗慢性足底溃疡有较好的临床疗效.  相似文献   
13.
14.
组织培养暗紫贝母的药理作用   总被引:6,自引:0,他引:6  
以组织培养的暗紫贝母为材料,野生暗紫贝母为对照,用不同溶剂提取,得4个化学组人 生物碱部分,总皂甙部分,水溶性部分和脂溶性部分,并以生药粉为阳性对照进行药效学试验。结果表明:组培贝母与野生贝母有相似的止咳、祛痰作用;总皂甙部分与总生物碱部分均为川贝有效活性成分,t得之间无显著性差异;经TLC是乌头总生物碱部分与总皂甙部分无化学成分重叠。  相似文献   
15.
Growing food crops to meet global demand and the search for more sustainable cropping systems are increasing the need for new cultivars in key production areas. This study presents the identification of rice traits putatively producing the largest yield benefits in five areas that markedly differ in terms of environmental conditions in the Philippines, India, China, Japan and Italy. The ecophysiological model WARM and sensitivity analysis techniques were used to evaluate phenotypic traits involved with light interception, photosynthetic efficiency, tolerance to abiotic stressors, resistance to fungal pathogens and grain quality. The analysis involved only model parameters that have a close relationship with phenotypic traits breeders are working on, to increase the in vivo feasibility of selected ideotypes. Current climate and future projections were considered, in the light of the resources required by breeding programs and of the role of weather variables in the identification of promising traits. Results suggest that breeding for traits involved with disease resistance, and tolerance to cold‐ and heat‐induced spikelet sterility could provide benefits similar to those obtained from the improvement of traits involved with canopy structure and photosynthetic efficiency. In contrast, potential benefits deriving from improved grain quality traits are restricted by weather variability and markedly affected by G × E interactions. For this reason, district‐specific ideotypes were identified using a new index accounting for both their productivity and feasibility.  相似文献   
16.
目的:观察健脾化瘀中药提高胞嘧啶脱氨酶/单纯疱疹病毒胸苷激酶基因治疗肝细胞癌的作用。方法:脂质体lipofectamine将含有双自杀基因的腺病毒载体pAd-CD/TK导人293细胞,收集病毒上清转染人肝癌细胞BEL7402,MTT法测定BEL7402细胞存活率。裸鼠人肝癌模型转染CD/TK双自杀基因后,给予5-FC500mg/kg,GCV 100mg/kg腹腔注射,同时予健脾化瘀中药960复方灌胃。观察肿瘤生长情况。结果:给予前体药物5-FC和GCV后,CD/TK转染细胞被杀死。并表现出较强的旁观者效应。转染细胞比例达到10%即表现出较强的杀伤作用(P<0.01)。健脾化瘀中药960复方具有提高旁观者效应作用,1.67ml/kg和2.5ml/kg960复方含药血清组细胞存活率显著低于对照组(P<0.01)。转染基因组应用5-FC和GCV治疗后,裸鼠肝癌的生长明显受到抑制(P<0.05),抑瘤率39.42%,单用中药组抑瘤率18.04%,中药与CD/TK 5-FC/GCV联合运用组,较单纯CD/5-FC/HSV-tk/GCV对裸鼠肿瘤模型的生长抑制作用更加明显(P<0.05),抑瘤率55.10%。结伦:腺病毒介导CD/TK自杀基因可有效地杀死人肝癌BEL7402细胞,健脾化瘀中药960复方具有显著提高CD/TK双自杀基因对人肝癌细胞的抑杀作用。  相似文献   
17.
利用甲基磺酸乙酯(EMS,ethyl methyl sulfonate)诱变剂处理野生型Yugu1(豫谷1号),在后代中发现了一个可以稳定遗传的颖花明显变窄的突变体,将其命名为sins1。与Yugu1相比,突变体sins1的株高显著降低了3.89%,穗长和穗粗分别显著降低了17.42%和21.62%,旗叶叶长和叶宽分别显著降低了15.09%和25.78%,千粒重显著降低了40.96%,谷码数显著降低了25%,均达到显著水平(P0.05)。利用突变体sins1为母本、SSR41为父本构建F_2定位群体,F_2正常颖花与窄颖花植株数目的分离比例为3∶1,表明该突变性状由隐性单基因控制。利用F_2群体隐性单株,最终将突变基因定位在3号染色体上SSR标记3-2658与CAAS3031间约7.709 Mb的距离内,为下一步精细定位提供了基础,同时也为促进禾本科作物颖花的研究提供了方向。  相似文献   
18.
Immature detached barley spikelets were cultured in wheat spikelet medium. Fertility of cultured barley spikelets was similar to that of cultured wheat spikelets. Barley anther development within cultured spikelets was retarded relative to in planta, but viability of developing pollen, as determined by a fluorochromatic reaction, was similar in vitro and in planta. Protein synthesis by anthers in developing barley spikelets in vitro was maximal during stage 2, when pollen grains were bicellular, and declined as pollen matured. Barley spikelet culture is an effective tool for the analysis of biochemical events in flower development.Abbreviations FRC fluorochromatic reaction - WSM wheat spikelet medium  相似文献   
19.
Synthesis and validation of crop models for assessment of of the impact of elevated atmospheric CO2 concentration and anticipated global warming on crop production require crop response data obtained under field-like conditions. The temperature gradient chamber (TGC) with the facility for CO2 enrichment allows the creation of various CO2 and temperature regimes for crops over the entire growth period with relatively inexpensive construction and running costs. The TGC develops a temperature gradient along its longitudinal axis using solar energy during the day and heating at night while maintaining the natural diurnal cycle. The temperature gradient and the CO2 concentration in the TGC are regulated by computer control of the air ventilation rate through the TGC and of the CO2 release rate. Longitudinal gradients of CO2 concentration and water vapour pressure deficit of air in the TGC were generally less than 5% and ±0.2 kPa, respectively. A CO2 enrichment experiment on rice in the TGC showed that a doubling of the CO2 concentration markedly enhanced crop dry matter production. Temperature had less effect on dry matter production, although panicle dry weight was greatly decreased at higher temperature as a result of high-temperature-induccd sterility of rice spikelets. Since rice spikclets are most sensitive to high temperature at the moment of flowering, and their flowering habit is highly synchronized with the diurnal courses of environmental conditions, the TGC is a useful tool in understanding rice responses to changes in atmosphere and temperature.  相似文献   
20.
The tassel seed mutations ts4 and Ts6 of maize cause irregular branching in its inflorescences, tassels, and ears, in addition to feminization of the tassel due to the failure to abort pistils. A comparison of the development of mutant and wild-type tassels and ears using scanning electron microscopy reveals that at least four reproductive meristem types can be identified in maize: the inflorescence meristem, the spikelet pair meristem, the spikelet meristem, and the floret meristem. ts4 and Ts6 mutations affect the fate of specific reproductive meristems in both tassels and ears. ts4 mutants fail to form spikelet meristems from spikelet pair meristems. Ts6 mutants are delayed in the conversion of certain spikelet meristems into floret meristems. Once floret meristems are established in both of these mutants, they form florets that appear normal but fail to undergo pistil abortion in the tassel. The abnormal branching associated with each mutant is suppressed at the base of ears, permitting the formation of normal, fertile spikelets. The classification of the different types of reproductive meristems will be useful in interpretation of gene expression patterns in maize. It also provides a framework for understanding meristem functions that can be varied to diversify inflorescence architectures in the Gramineae.  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