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81.
用有界线性算子代替压缩常数,在序Banach空间中引入了几种压缩型映射,并证明了相应的不动点定理. 相似文献
82.
荒溪灾害危险区制图(长期预报)是同荒溪分类一并进行治理山区、建设山区、防治荒溪灾害、实现山区可持续发展战略的一项基础性工作。本研究介绍了荒溪灾害危险区制图的具体方法,并已在整个北京山区推广实施,为我国荒溪灾害预报场地的基础危险性研究做了一项行之有效的工作。 相似文献
83.
综述了动物分子遗传学的发展与现状,并对分子遗传学的方法和各领域的最新研究成果作了全面的分析介绍。根据动物科技学科的发展趋势,提出了动物分子遗传学的发展方向。 相似文献
84.
数字制图的特点及其应用 总被引:4,自引:0,他引:4
本文分析了信息时代地球科学领域数字制图的特点,提出了遥感、GIS等新技术与数字制图相结合的理论基础,并强调了数据采集与更新及可视化与虚拟现实技术等关键性问题,从资源合理利用、生态环境整治及社会经济发展的角度展望了数字制图技术广阔的应用前景。 相似文献
85.
86.
Gaofeng?Jia Peidu?ChenEmail author Genji?Qin Guihua?Bai Xiue?Wang Suling?Wang Bo?Zhou Shouzhong?Zhang Dajun?Liu 《Euphytica》2005,146(3):183-191
Summary A doubled haploid (DH) wheat population derived from the cross Wangshuibai/Alondra‘s’ was developed through chromosome doubling
of haploids generated by anther culture of hybrids. Fusarium head blight (FHB) was evaluated for three years from 2001 to
2003 in Jianyang, Fujian Province, China, where epidemics of FHB have been consistently severe. After 307 pairs of simple
sequence repeat (SSR) primers were screened, 110 pairs were polymorphic between Wangshuibai and Alondra`s’, and used to construct
a genetic linkage map for detection of quantitative trait loci (QTLs). A stable QTL for low FHB severity was detected on chromosomes
3B over all three years, and QTLs on chromosomes 5B, 2D, and 7A were detected over two years. Additional QTLs on chromosomes
3A, 3D, 4B, 5A, 5D, 6B and 7B showed marginal significance in only one year. Six QTLs were detected when phenotypic data from
three years were combined. In addition, significant additive-by-additive epistasis was detected for a QTL on 6A although its
additive effect was not significant. Additive effects (A) and additive-by-additive epistasis (AA) explained a major portion
of the phenotypic variation (76.5%) for FHB response. Xgwm533-3B and Xgwm335-5B were the closest markers to QTLs, and have potential to be used as selectable markers for marker-assisted selection (MAS)
in wheat breeding programs. 相似文献
87.
Molecular mapping of an aluminum tolerance locus on chromosome 4D of Chinese Spring wheat 总被引:13,自引:0,他引:13
Summary The tolerance of aluminum (Al) of disomic substitution lines having the chromosomes of the D genome of Triticum aestivum L. cv. Chinese Spring individually substituted for their homoeologues in T. turgidum L. cv. Langdon was investigated by the hematoxylin method. The disomic substitution lines involving chromosome 4D were more Al tolerant than Langdon. The tolerance was found to be controlled by a single dominant gene, designated Alt2, that is in the proximal region of the long arm of chromosome 4D. The locus was mapped relative to molecular markers utilizing a population of recombinant chromosomes from homoeologous recombination between Chinese Spring chromosome 4D and T. turgidum chromosome 4B. Comparison of the location of Alt2 in this map with a consensus map of chromosomes 4B and 4D based on homologous recombination indicated that Alt2 is in a vicinity of a 4 cM interval delineated by markers Xpsr914 and Xpsr1051. The Alt2 locus is distal to marker Xpsr39 and proximal to XksuC2. The Altw locus is also proximal to the Knal locus on chromosome 4D that controls K+/Na+ selectivity and salt tolerance. In two lines, Alt 2 and Knal were transferred on a single 4D segment into the long arm of T. turgidum chromosome 4B. 相似文献
88.
三黄占2号稻瘟病抗性与稻米直链淀粉含量的关系研究 总被引:3,自引:0,他引:3
以高抗稻瘟病、直链淀粉含量(AC)较高的三黄占2号和高感稻瘟病、AC较低的丽江新团黑谷衍生的重组自交系群体为研究材料,从性状的相关性和控制两性状的基因在染色体上的位置关系剖析稻瘟病抗性和稻米AC的内在关系。结果表明,两性状间没有显著的相关性。3个与AC相关的QTL分别被定位在第5、6和7染色体上,其加性效应均来自丽江新团黑谷,起降低AC的作用。比较这些QTL与先前对同一群体鉴定的稻瘟病抗性基因(主效基因和QTL)在染色体上的位置,表明控制这两性状的基因上没有紧密连锁关系, 亦没有显著的基因间互作。据此认为,通过亲本的合理选择和分子标记辅助选择可以把三黄占2号稻瘟病持久抗性与理想AC整合到同一品系中,育成优质、抗病的优良品种。 相似文献
89.
Change of Brain Electrical Impedance has great relations with brain oedema and brain block, a new method of Examining Brain Oedema through Brain Electrical Impedance Topographic Mapping(BEITM)is reviewed. Network topology structure that used in BEITM are also presented. According to topology, we discuss the drawing algorithm that based on triangle element. Some patients have been measured to make clinical data, according to this data Brain Electrical Impedance topographic come into being by computer at last, functional imaging has been implemented. Clinical case analysis compared with change state of an illness and repeatability of steady patient's data has proved the method is feasible. 相似文献
90.
An introduction to markers, quantitative trait loci (QTL) mapping and marker-assisted selection for crop improvement: The basic concepts 总被引:24,自引:2,他引:24
Recognizing the enormous potential of DNA markers in plant breeding, many agricultural research centers and plant breeding institutes have adopted the capacity for marker development and marker-assisted selection (MAS). However, due to rapid developments in marker technology, statistical methodology for identifying quantitative trait loci (QTLs) and the jargon used by molecular biologists, the utility of DNA markers in plant breeding may not be clearly understood by non-molecular biologists. This review provides an introduction to DNA markers and the concept of polymorphism, linkage analysis and map construction, the principles of QTL analysis and how markers may be applied in breeding programs using MAS. This review has been specifically written for readers who have only a basic knowledge of molecular biology and/or plant genetics. Its format is therefore ideal for conventional plant breeders, physiologists, pathologists, other plant scientists and students. 相似文献