七姊妹山国家级自然保护区悬钩子属植物资源及开发利用研究     

方元平  满金山  彭宗林  刘胜祥 《黄冈师范学院学报》2008,28(6):29-32

悬钩子属是蔷薇科中的一个大属,全世界有悬钩子属植物750余种。在野外调查和文献资料查阅的基础上,对七姊妹山国家级自然保护区悬钩子属植物的野生种的分布、生长习性等现状进行了研究。结果表明：该保护区有悬钩子属植物35种和7变种,且资源蕴藏量大。按其用途可将其分为食用植物类、药用植物类、工业用植物类和观赏植物类等,如能有计划地加以开发利用,对当地经济发展将会起到积极的促进作用。  相似文献   

A Review of Research on Technology-Assisted Teaching and Learning of Chinese as a Second or Foreign Language from 2008 to 2018     

Boning LYU  Xuedan QI 《Frontiers of Education in China》2020,15(1):142

More and more studies are examining the use of technology in the teaching of Mandarin Chinese as a second or foreign language (L2 Chinese). The current study involved a systematic review of the literature in the field published outside China from 2008 to 2018. A total of 33 studies met the inclusion criteria. The current review study aimed: (1) to examine the research topics and technologies used in the literature; (2) to identify the benefits of, and challenges involved in, the use of technologies in L2 Chinese teaching and learning; and (3) to suggest implications for practitioners and directions for further research. The review study provides educators and researchers with an overview of recent developments in this field, which could be helpful in informing teaching practice and further research.  相似文献   

干旱胁迫对不同玉米品种叶片膜透性的影响     

卡德尔·阿布都热西提 《喀什师范学院学报》2008,29(6):57-59

对不同玉米品种进行干旱处理,对叶片含水量、土壤含水量、叶片质膜透性进行测定．结果表明,土壤干旱胁迫条件下,玉米叶片含水量下降,叶片质膜透性上升;随着胁迫时间的延长,即土壤含水量的降低,叶片质膜透性不断的增加,其中新实1号的变化幅度最小,而叶片含水量则随之不断的减少,与叶片质膜透性的结果相符．这说明幼苗期新实1号的抗旱能力较强．因此,对叶片含水量、土壤含水量、叶片质膜透性的测定可以作为幼苗期抗旱鉴定的重要指标．  相似文献   

葱内生真菌抑菌活性初探     

李光富  ;汪正威  ;李雪玲 《楚雄师专学报》2008,(9):75-80

目的：从葱的根、茎、叶中分离内生真菌,并进行初步抗菌活性检测,得到具有高抗菌活性的菌株。方法：1．用PDA培养基分离葱的内生真菌;2．用查氏培养基进行发酵实验。3．进行滤纸片抑菌实验。结果：从葱中分离出的17株内生真菌,均具有抗菌活性,其中,抑菌圈直径大于1．0cm的高抗菌性菌株有11株,占总分离菌株数的64．71％。结论：葱内生真菌具有类似宿主植物葱一样的广泛抗菌性（分离得到的17株内生真菌均具有抗菌性）,但由于宿主植物本身所具有的强抗菌性,使分离得到的菌株种属多样性较少。  相似文献   

国外二语词汇深度测量工具综述     

秦学锋  魏怀玺  聂景俊 《湖北广播电视大学学报》2008,28(2):103-104

本文对两种二语词汇深度测量工具（VKS和WAT）进行了回顾和总结,并对二语词表、二语词汇知识做了简单描述。文章指出,VKS和WAT在研究和测量二语词汇知识方面有各自的特点和不足,因此,研究者应结合研究目的,正确选择和利用这两种工具。  相似文献   

西南女贞属(木犀科)一新种     

缪柏茂 《中国科学院研究生院学报》1988,26(3):241-242

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大麦抗赤霉病性的遗传研究     

陆美琴  赵理清 《科技通报》1995,11(6):365-369

采用特矮大麦／早熟３号、特矮大麦／紫皮大麦、特矮大麦９１－６４１１、９１－６４１１／早熟３号４具杂交组合的Ｐ１、Ｐ２、Ｆ１、Ｆ２、Ｂ１、Ｂ２世代，研究了大麦抗赤霉病性的遗传，结果表明，大麦抗郝霉病性表现 部分显性或超显性，细胞质作用不明显，在特矮大麦／早熟３号、特矮大麦／紫大麦和特矮大麦／９１－６４１１中，共同亲本特矮大感病性主要受一对隐性基因控制；在９１－６４１１／早熟３号中，抗赤霉病性为数量性  相似文献   

Measuring patent assessment quality—Analyzing the degree and kind of (in)consistency in patent offices’ decision making   总被引：1，自引：0，他引：1  

Paul F. Burke  Markus Reitzig 《Research Policy》2007,36(9):1404-1430

We argue that consistent decision making in judging a patent's validity and basing this on its underlying technological quality are important elements of patent office service (“assessment”) quality. To understand which level of assessment quality patent offices (can) provide, particularly in new technological areas, we study the concordance of the European Patent Office's (EPO) granting and opposition decisions for individual patents. Using the biotechnology industry in the 1980s (an emerging patenting area then) as an example, we find no empirical evidence that the EPO provided maximal or optimal assessment quality as far as can be told from bibliographic indicators. We discuss research limitations and consequences of this first empirical analysis, and suggest ideas for refinements in future work.  相似文献   

The birth of a new industry: entry by start-ups and the drivers of firm growth: The case of encryption software     

Marco S Giarratana 《Research Policy》2004,33(5):787-806

The paper analyses the birth of the encryption software industry (ESI), a new niche in the software industry. Using a Chandlerian perspective, this work reports the main facts about firm entry and growth, with a particular focus on start-up strategies and actions.Since scale economies do not play a major role in ESI, the paper investigates the different sources of firm competitive advantages.This work shows that innovation and product differentiation, along with investments in co-specialised assets, are variables strongly correlated to young firm probability to survive and grow. In doing so, we have collected highly detailed information on product introduction, US patents granted, worldwide alliances and biographical data of firm founders.  相似文献   

Scientific teams and institutional collaborations: Evidence from U.S. universities, 1981-1999     

James D. Adams  Grant C. Black  Paula E. Stephan 《Research Policy》2005,34(3):259-285

This paper explores recent trends in the size of scientific teams and in institutional collaborations. The data derive from 2.4 million scientific papers written in 110 top U.S. research universities over the period 1981-1999. The top 110 account for a large share of published basic research conducted in the U.S. during this time.We measure team size by the number of authors on a scientific paper. Using this measure we find that team size increases by 50% over the 19-year period. We supplement team size with measures of domestic and foreign institutional collaborations, which capture the geographic dispersion of team workers. The time series evidence suggests that the trend towards more geographically dispersed scientific teams accelerates beginning with papers published at the start of the 1990s. This acceleration suggests a sharp decline in the cost of collaboration. Our hypothesis is that the decline is due to the deployment of the National Science Foundation's NSFNET and its connection to networks in Europe and Japan after 1987.Using a panel of top university departments we also find that private universities and departments whose scientists have earned prestigious awards participate in larger teams, as do departments that have larger amounts of federal funding. Placement of former graduate students is a key determinant of institutional collaborations, especially collaborations with firms and with foreign scientific institutions. Finally, the evidence suggests that scientific output and influence increase with team size and that influence rises along with institutional collaborations. Since increasing team size implies an increase in the division of labor, these results suggest that scientific productivity increases with the scientific division of labor.  相似文献