全文获取类型
| 收费全文 | 20410篇 |
| 免费 | 5887篇 |
| 国内免费 | 983篇 |
专业分类
| 林业 | 608篇 |
| 农学 | 2750篇 |
| 基础科学 | 41篇 |
| 1138篇 | |
| 综合类 | 9872篇 |
| 农作物 | 2086篇 |
| 水产渔业 | 1316篇 |
| 畜牧兽医 | 6795篇 |
| 园艺 | 1261篇 |
| 植物保护 | 1413篇 |
出版年
| 2025年 | 499篇 |
| 2024年 | 540篇 |
| 2023年 | 628篇 |
| 2022年 | 948篇 |
| 2021年 | 1081篇 |
| 2020年 | 1086篇 |
| 2019年 | 1161篇 |
| 2018年 | 890篇 |
| 2017年 | 1149篇 |
| 2016年 | 1364篇 |
| 2015年 | 1243篇 |
| 2014年 | 1211篇 |
| 2013年 | 1196篇 |
| 2012年 | 1756篇 |
| 2011年 | 1765篇 |
| 2010年 | 1381篇 |
| 2009年 | 1301篇 |
| 2008年 | 1213篇 |
| 2007年 | 1369篇 |
| 2006年 | 1113篇 |
| 2005年 | 881篇 |
| 2004年 | 647篇 |
| 2003年 | 525篇 |
| 2002年 | 391篇 |
| 2001年 | 385篇 |
| 2000年 | 296篇 |
| 1999年 | 250篇 |
| 1998年 | 160篇 |
| 1997年 | 122篇 |
| 1996年 | 126篇 |
| 1995年 | 83篇 |
| 1994年 | 89篇 |
| 1993年 | 68篇 |
| 1992年 | 76篇 |
| 1991年 | 54篇 |
| 1990年 | 31篇 |
| 1989年 | 41篇 |
| 1988年 | 23篇 |
| 1987年 | 29篇 |
| 1986年 | 19篇 |
| 1985年 | 6篇 |
| 1984年 | 4篇 |
| 1982年 | 7篇 |
| 1981年 | 4篇 |
| 1977年 | 4篇 |
| 1973年 | 1篇 |
| 1963年 | 4篇 |
| 1962年 | 11篇 |
| 1956年 | 19篇 |
| 1955年 | 24篇 |
排序方式： 共有10000条查询结果，搜索用时 20 毫秒
11.
Naoki Yamanaka Mio Morishita Tomomi Mori Yukie Muraki Midori Hasegawa Md. Motaher Hossain Yuichi Yamaoka Masayasu Kato 《Plant Breeding》2016,135(5):621-626
Asian soybean rust (ASR) caused by Phakopsora pachyrhizi is one of the most serious soybean (Glycine max) diseases in tropical and subtropical areas. A soybean line, PI 587855, showed a resistance phenotype against ASR pathogens in Japan and South America at high frequency; however, little is known of the genetic control of this resistance and chromosomal location of the corresponding locus. Therefore, the aim of this study was to study the inheritance of PI 587855 resistance and map the corresponding locus with SSR markers aiming to use the linked markers in marker‐assisted selection. In the segregating population, resistance to ASR appeared to be controlled by a single dominant gene. The ASR resistance locus was mapped near to the chromosomal region where the resistant loci, Rpp1 and Rpp1‐b, were previously mapped. Comparative genetic mapping and disease reaction profiles of other seven lines carrying Rpp1 or Rpp1‐b to four Brazilian ASR isolates revealed that the resistance reaction exhibited by PI 587855 was similar to that of Rpp1‐b‐carrying varieties which have useful resistance to South American ASR strains. 相似文献
12.
Rafał Podlaski 《European Journal of Forest Research》2004,123(3):229-237
This article presents a validation of a method, proposed in Podlaski (2003), for estimating the degree of tree damage. This method belongs to a group of small-area methods. To estimate the degree of tree damage in individual P3 sub-blocks of the SINUS system of information on the natural environment, a classification based on the degree of defoliation was used. Spatial distribution of the degree of tree damage was estimated through unrestricted simple random sampling. The maximum total estimation error for proportions of fir and beech with a damage degree of zero, and also with second and third degrees jointly, reached a maximum of 35.6% for fir, and 33.8% for beech. P3 sub-blocks characterised by the highest proportion of the healthiest trees (at least 15% being undamaged trees) occurred in patches in the case of fir, and in larger, compact areas in the case of beech. Because spatial diversification in the health of fir, and to a smaller degree in the case of beech, occurs at small scales, small-area methods for estimating tree condition are necessary. An analogous scheme, combining small-area with large-area methods (utilising sub-blocks of the network of large-area systems in a small-area inventory, and establishing a common database), could be used on a wider scale; for example, by supplementing the program of estimating tree health carried out by the United Nations Economic Commission for Europe (Lorenz et al. 2002) with local inventories. 相似文献
13.
14.
M. Fladung 《Plant Breeding》1993,111(3):242-245
The iaaL gene of Pseudomonas syringae subsp. savastanoi encodes an indoleacetic acid-lysine synthetase which conjugates free indoleacetic acid (IAA) with lysine. lAA-lys is biologically less active than free IAA. The iaaL coding region was expressed under the control of the cauliflower mosaic virus 35S promoter and transgenic potato plants were produced (Spena et al. 1991). 35S iaaL potato plants are characterized by increased internodal length and epinastic bending of older leaves. In three greenhouse experiments with plants grown in pots of different size and in two growth chamber experiments tuber number increased in iaaL transgenic plants compared to untransformed and vector-transformed controls of the same genotype. The increase in tuber numbers observed under controlled conditions was reflected in tuber yield which increased in the pot grown transgenics. 相似文献
15.
16.
The effects of the Yd2 gene on tolerance to barley yellow dwarf virus (BYDV) and other agronomically important characters in spring barley were evaluated in a set of randomly selected doubled haploid (DH) lines of an‘Igri’/‘Atlas 68’ cross and three crosses between CIMMYT Yd2 materials and the Czech malting barley ‘Akcent’. The cleaved amplified polymorphic site (CAPS) diagnostic marker Yd2 was used for identification of the Yd2 gene and this analysis showed high agreement with the results of field infection tests. Yd2 lines exhibited significantly lower symptom scores and lower reductions of some grain yield characters, but their resistance level was not consistent over the years. The presence of secondary stresses (high temperature/drought) in 2000 led to relatively higher sensitivity to BYDV infection, strengthened by the long life cycle of genotypes. In cases where secondary stresses were mild (in 2002), the longer life cycle significantly increased sensitivity to BYDV infection only in the absence of the Yd2 gene (in susceptible genotypes). The examination of different vegetative, grain yield and malting quality characters separately for groups of Yd2 and non‐ Yd2 lines did not show any evidence of adverse effect of the Yd2 gene on any character. 相似文献
17.
目的探讨亚砷酸对人胰腺癌PANC-1细胞增殖及RAS相关结构域家族基因1A（RASSHA）甲基化的影响。方法PANC-1细胞用不同浓度亚砷酸处理,采用MTT法检测细胞增殖,甲基化特异性PCR（MSV）法检测RASSFlA基因甲基化情况。结果随着亚砷酸浓度增加（1．2～4．8μmol／L）和作用时间延长,PANC-1细胞抑制率逐渐增加（P〈0．05）。PANC－1细胞中RASSFlA基因表现为高甲基化状态,但其甲基化随亚砷酸浓度增加而逐渐减弱。结论亚砷酸对PANC－1细胞增殖的抑制作用具有时间和剂量依赖性,并通过RASSFlA基因的去甲基化起作用。 相似文献
18.
Drought is one of the most important environmental constraints limiting plant growth, development and crop yield. Many drought-inducible genes have been identified by molecular and genomic analyses in ... 相似文献
19.
采用限制性内切酶Sau3AI、MspI、TaqαI、AluI分别对获得的L16基因序列进行理论酶切。通过限制性内切酶酶切后,酶切片段大小相同的记为1,不同的记为0。相似系数和聚类分析应用NTSYS-pc2.01数据分析软件进行,采用Nei的方法计算相似系数,UPGMA方法聚类,绘制树状图。结果表明芭蕉属种间存在较为丰富的cpDNA PCR-RFLP多态性,种内差异性不明显,有些亚种间无法区分开。而M. acuminata 具有丰富的亚种和变种,遗传差异大,多样性丰富。 相似文献
20.