全文获取类型
收费全文 | 701篇 |
免费 | 48篇 |
国内免费 | 73篇 |
专业分类
林业 | 43篇 |
农学 | 92篇 |
基础科学 | 15篇 |
104篇 | |
综合类 | 218篇 |
农作物 | 41篇 |
水产渔业 | 93篇 |
畜牧兽医 | 145篇 |
园艺 | 50篇 |
植物保护 | 21篇 |
出版年
2023年 | 12篇 |
2022年 | 9篇 |
2021年 | 17篇 |
2020年 | 19篇 |
2019年 | 13篇 |
2018年 | 19篇 |
2017年 | 22篇 |
2016年 | 33篇 |
2015年 | 21篇 |
2014年 | 42篇 |
2013年 | 40篇 |
2012年 | 61篇 |
2011年 | 54篇 |
2010年 | 32篇 |
2009年 | 49篇 |
2008年 | 64篇 |
2007年 | 45篇 |
2006年 | 56篇 |
2005年 | 28篇 |
2004年 | 32篇 |
2003年 | 30篇 |
2002年 | 25篇 |
2001年 | 15篇 |
2000年 | 11篇 |
1999年 | 18篇 |
1998年 | 16篇 |
1997年 | 14篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有822条查询结果,搜索用时 15 毫秒
81.
Molecular cytogenetic identification of wheat-Elymus tsukushiense introgression lines 总被引:3,自引:0,他引:3
Elymus tsukushiense Honda (syn. Roegneria kamoji C. Koch) (2n = 6x = 42, StsStsHtsHtsYtsYts) is a hexaploid species, distantly related to bread wheat Triticum aestivum L. em Thell (2n = 6x = 42, AABBDD). Apart from
the delineation of evolutionary relationships, this species is a potential source of resistance to scab, a devastating disease
of wheat caused by Fusarium graminearum Schw. A standard C-banded karyotype was established identifying all 21 chromosome
pairs of E. tsukushiense. By using C-banding and genomic in situ hybridization analyses, three wheat-E. tsukushiense chromosome
addition lines, one ditelosomic addition line, and one disomic substitution line were identified in BC2 progenies from wheat × E. tsukushiense hybrids. Twenty DNA markers specific for the seven homoeologous groups of the Triticeae
were used to determine the homoeology of the added E. tsukushiense chromosomes. The E. tsukushiense chromosomes in the addition
lines NAU702, NAU703, and NAU701 were identified as belonging to homoeologous groups 1, 3, and 5, and thus, were designated
as 1Ets#1, 3Ets#1, and 5Ets#1, respectively. NAU751 was identified as a disomic substitution line with chromosome 3A of wheat
replaced by chromosome 3Ets#1. Line NAU702 has a high level of resistance to scab and will be used in chromosomal engineering
and development of improved wheat germplasm for scab resistance breeding.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
82.
R. Zhou J. Jia Y. Dong T. Schwarzacher S.M. Reader S. Wu M.D. Gale T.E. Miller 《Euphytica》1998,99(2):85-88
Using the genomic in situ hybridization (GISH) technique, one translocation line, seven translocation-addition lines, five
translocation plus translocation addition lines and two ditelosomic addition lines were identified in backcross progenies
of Triticum aestivum L. -Psathyrostachys juncea (Fisch.) Nevski intergeneric hybrids. No complete P. juncea chromosomes were
detected in the 25 lines studied. The results suggest that intact P. juncea chromosomes may be difficult to isolate in a wheat
background.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
83.
Characterization of wheat-triticale doubled haploid lines by cytological and biochemical markers 总被引:2,自引:0,他引:2
Five wheat-triticale doubled haploid (DH) lines— M08, V209, DH220-14-2, DH696-3-4 and M16 —derived from anther culture of F1s resulting from crosses involving hexaploid or octoploid triticale × hexaploid wheat, were characterized by cytological and biochemical markers. Cytological evidence from genomic in situ hybridization and C-banding indicated that DH lines M08 and V209 (2n= 42) each contained a pair of 1BL/1RS translocation chromosomes. DH220-14-2 (2n= 42) was also a translocated line with two pairs of chromosomes containing small fragments of rye. One of the translocation fragments carried the Sec-1R gene originating from the satellite region of 1RS; the origin of the other one remains unknown. DH696-3-4 (2n= 42) contained a 3D(3R) substitution. In M16 (2n= 44), three pairs of rye chromosomes, 3R, 4R and 6R, were present, 4R as an addition and 3D(3R) and 6D(6R) as substitutions. Biochemical, isozyme and storage protein markers confirmed the cytological conclusions. The advantages of transferring alien chromosomes or chromosome fragments into wheat and creating alien aneuploid lines by anther culture of hybrid F1s are discussed. 相似文献
84.
用荧光原位杂交技术检测黑麦染色质 总被引:10,自引:0,他引:10
荧光原位杂交技术(fluorescence in situ hybridization ,FISH)是一种快速、准确、直接检测和定位外源染色质的新技术。本研究荧光原位杂交用毛地黄毒苷-11-dUTP标记黑麦总DNA作探针,以检测小麦中黑麦染色质。结果如下:八倍体小黑麦(2n=8x=56)有丝分裂中期有14条染色体显示黄色,42条染色体显示红色,红色间期核显示有14个黄色亮点,表明这八倍体小黑麦含14条黑麦染色体。八倍体小黑麦中黄色黑麦染色体显C-带和H-带的末端有绿色的带。这是由于黑麦染色体末端结构异染色质含量高所致。黑麦附加系2R的间期细胞核中有1 ~ 2个黄色亮点。这表明2R含有1至2条黑麦染色体。 相似文献
85.
整体荧光原位杂交用于检测水稻特异DNA程序的研究 总被引:1,自引:1,他引:0
文章报道了整体荧光原位杂交应用于检测水稻特异DNA的实验程序。利用该实验方法,以经地高辛(DIG)标记的rDNA作为探针,成功地在水稻根尖和花药内部组织检测与探针互补的片段。对于实验方法,结果表明,整体荧光原位杂交的成功与否受到多种因素的影响,包括组织的种类、固定剂的种类以及固定后的处理方法(主要是酶解与否)等。检测根尖DNA可以采用φ(福尔马林)=1%固定加上酶解;检测花药(花粉发育处于单核期) 相似文献
86.
Ex situ conservation of genetic resources has contributed to the improvement of several food crops through utilisation of preserved germplasm, but it is not the only approach to safeguard genetic resources. Presently, in situ methods are being examined as effective complementary strategies to preserve diversity along with the dynamic environment. Examples of de facto on farm conservation, a form of in situ, have been described. However, their future is unpredictable without the relief of formal scientific projects or appropriate regulations. Recent European Community regulations have introduced the possibility to attribute marks of origin and quality to local typical products. These marks can be an important support to on farm maintenance of élite landraces of principal crops. In the frame of a collaboration between the Italian gene bank and a farm (of the agricultural research service of Basilicata region), an integrated approach, involving ex situ and on farm conservation, was adopted to safeguard common bean landraces from Basilicata. The main result of this project was the attribution of IGP (indication of geographic provenance), an European Community mark, to some tested landraces. 相似文献
87.
以本实验室构建的半滑舌鳎BAC文库为基础,通过对其进行有序混合,构建了两步PCR筛选体系;对性别决定相关的sox9基因的序列设计特异性引物,筛选获得阳性单一BAC克隆。利用BAC-FISH技术将包含sox9基因的BAC克隆定位在半滑舌鳎染色体上。结果显示,sox9基因在雌、雄半滑舌鳎的一对常染色体的长臂上分别存在两个杂交信号位点,信号稳定且特异。研究证实了该文库筛选体系的有效性;首次实现了对性别相关的sox9基因在半滑舌鳎染色体上的定位,其结果为揭示sox9基因参与鱼类性别控制的机制提供了重要基础。 相似文献
88.
89.
90.
圆口铜鱼人工繁殖及胚胎发育研究 总被引:1,自引:0,他引:1
鉴于金沙江梯级电站开发运行、鱼类栖息地减少、洄游通道受阻、自然繁殖受到影响、早期资源量显著下降、种群生存面临危机的现状,为了保护鱼类种质资源,通过人工增殖放流是补充其资源量的主要补救措施。利用船体网箱原位活水驯养的圆口铜鱼(Coreius guichenoti)亲鱼,开展亲鱼驯养、人工催产和胚胎发育研究。结果表明,圆口铜鱼亲鱼在船体网箱活水驯养条件下,性腺发育成熟,可用于人工催产。2017年6月17~30日,采用二次注射法人工催产3批次,共产卵约12万粒,在水温20.5~21.9 ℃条件下,针距8~10 h,效应时间18~19 h,平均受精率69.3%,出苗约5万尾。圆口铜鱼卵径1.9~2.2 mm,卵膜径6.4~7.2 mm,胚胎发育过程分为受精卵、卵裂期、囊胚期、原肠期、神经胚期、器官形成期和出膜期7个阶段,在水温20.5~22.5 ℃,溶氧7 mg/L以上条件下,历时48~62 h出膜。研究结果为圆口铜鱼人工繁殖技术提供了参考,为其规模化人工增殖放流提供了保障。 相似文献