全文获取类型
收费全文 | 14981篇 |
免费 | 654篇 |
国内免费 | 719篇 |
专业分类
林业 | 1853篇 |
农学 | 1376篇 |
基础科学 | 164篇 |
584篇 | |
综合类 | 7443篇 |
农作物 | 752篇 |
水产渔业 | 1358篇 |
畜牧兽医 | 1234篇 |
园艺 | 1372篇 |
植物保护 | 218篇 |
出版年
2024年 | 40篇 |
2023年 | 87篇 |
2022年 | 203篇 |
2021年 | 248篇 |
2020年 | 312篇 |
2019年 | 334篇 |
2018年 | 147篇 |
2017年 | 380篇 |
2016年 | 451篇 |
2015年 | 444篇 |
2014年 | 616篇 |
2013年 | 724篇 |
2012年 | 1109篇 |
2011年 | 1106篇 |
2010年 | 1019篇 |
2009年 | 1065篇 |
2008年 | 966篇 |
2007年 | 1133篇 |
2006年 | 987篇 |
2005年 | 824篇 |
2004年 | 590篇 |
2003年 | 491篇 |
2002年 | 373篇 |
2001年 | 331篇 |
2000年 | 268篇 |
1999年 | 266篇 |
1998年 | 241篇 |
1997年 | 204篇 |
1996年 | 210篇 |
1995年 | 178篇 |
1994年 | 160篇 |
1993年 | 168篇 |
1992年 | 125篇 |
1991年 | 132篇 |
1990年 | 128篇 |
1989年 | 83篇 |
1988年 | 63篇 |
1987年 | 43篇 |
1986年 | 34篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1955年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
121.
以穿龙薯蓣的丛生芽为材料,对根的诱导及快速繁殖进行了研究,并利用反相高效液相色谱技术对根中薯蓣皂苷元含量进行了测定,结果如下:不添加任何激素的1/2MS培养基是诱导生根的最佳培养基,生根率最高达76.7%;MS+0.2 mg/L NAA+0.5 mg/L IBA+0.2-0.5 mg/L PP333为根增殖的最佳培养基,60 d时增殖倍数超过93;快繁过程中根的生长形态发生变化,不同类型的根中薯蓣皂苷元含量差异不显著,平均为0.21% 相似文献
122.
针对晋阳345和晋麦73两个定型品种存在抗寒性较差的缺点,对其幼胚愈伤组织进行了4种处理:1、愈伤组织在MD培养基上继代2~3次;2、愈伤组织在紫外灯下约10cm照射2h;3、愈伤组织在低温2℃和常温25℃下交替培养30d;4、愈伤组织在紫外灯下照射2h后,再在低温2℃和常温25℃下交替培养30d。结果表明,4个处理后代R2主要农艺性状的变异率差异显著,且紫外灯照射幼胚愈伤组织的变异率比低温2℃和常温25℃交替处理幼胚愈伤组织高,其后代各种农艺性状的变异范围较大,变异率较高。但后者有利于改良抗寒性较差的定型小麦品种。 相似文献
123.
124.
It has been briefly studied and reported that Actinidia chinensis , one of economic woody plants, has been bred with the method of plant tissue culture. Aim at the shortage of traditional plant tissue culture ways which ignored the refinement and transplant of test-tube seedling, it strengthen the study to breeding and management of Actinidia chinensis seedlings before they grow up and become mature seedlings. Through our explore, the transplant survive rate of tissue-culture seedlings attain to about 85%.This study is the improvement to traditional breeding seedling means and it is helpful to the rapid propagation of those economic woody plants. 相似文献
125.
It is a burgeoning application field for the biotechnology that to apply the technique of plant tissue culture breed seedling. The authors study the responses of Echinacea purpurea to different proportion plant growth hormone or auxin through adopting the culture tissue technique on the MS. The integrated seedling of Echinacea purpurea can be cultivated by callus, subculture, differentiation and rhizogenesis. The surviving rate of Echinacea purpurea seedling transplant are improved by appropriate sound stimulation appropriate. Study harvest offers the gist for the large-scale breeding seedling and the officinal resource exploitation of Echinacea purpurea in our country, and avoid some traditional handicap in breeding seedling of Echinacea purpurea, such as the difficult of seed collection, low burgeoning rate, and the disadvantage for large-scale propagation. 相似文献
126.
YANG Zhong-ren RAO Cheng ZOU Jian PENG Zhen-liane Ministry of Education Chongqing Chin 《保鲜与加工》2004,(2):32-35
Dong village is very valuable for research work because of its special regional and national character and rich cultural implication. In this paper, some information about the location, form and features of Dong village is given. Then, the relationship between the culture and the settlement is analyzed, which provides a clue for understanding Dong village and will be beneficial to creating modern human settlements. 相似文献
127.
Based on the content of enterprise culture and enterprise credit, it is pointed out that the enterprise culture related to the enterprise core competitive force.In this paper, from the viewpoint of combining theory with practice, the intension, function and mutual relations between them are described and their significance in the market competition as well.The potential things,which the enterprise staffs are seeking for, from its inherent mind and the enterprise theory are the enterprise culture which becomes the enterprise core competitive force in its actual sense.The enterprise credit, as the enterprise culture in its ideological sphere, is an essential factor, which greatly affects the enterprise core competitive force.At last the authors provide some good suggestions on how to cultivate enterprise credit and to build enterprise culture. 相似文献
128.
129.
LI Ting - ting 《保鲜与加工》2006,(1):35-39
Under the special social background and source of history, the western architectural culture affected the traditional dwellings in Meizhou from the 19th century till the 20th century. The framework, outline and materials of traditional dwellings were changed in certain extent while the form of plane layout and interior decoration still stood stable maintaining the native characters. This article analyzes the phenomena of incorporation of things with diverse nature. 相似文献
130.