全文获取类型
收费全文 | 3415篇 |
免费 | 260篇 |
国内免费 | 245篇 |
出版年
2023年 | 35篇 |
2022年 | 56篇 |
2021年 | 172篇 |
2020年 | 128篇 |
2019年 | 153篇 |
2018年 | 162篇 |
2017年 | 109篇 |
2016年 | 132篇 |
2015年 | 195篇 |
2014年 | 262篇 |
2013年 | 257篇 |
2012年 | 339篇 |
2011年 | 287篇 |
2010年 | 167篇 |
2009年 | 147篇 |
2008年 | 182篇 |
2007年 | 132篇 |
2006年 | 126篇 |
2005年 | 103篇 |
2004年 | 82篇 |
2003年 | 94篇 |
2002年 | 79篇 |
2001年 | 41篇 |
2000年 | 57篇 |
1999年 | 61篇 |
1998年 | 33篇 |
1997年 | 28篇 |
1996年 | 23篇 |
1995年 | 30篇 |
1994年 | 27篇 |
1993年 | 23篇 |
1992年 | 34篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 19篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1969年 | 3篇 |
1966年 | 2篇 |
1951年 | 2篇 |
排序方式: 共有3920条查询结果,搜索用时 15 毫秒
71.
Integrated genome sequence and linkage map of physic nut (Jatropha curcas L.), a biodiesel plant 下载免费PDF全文
Pingzhi Wu Changpin Zhou Shifeng Cheng Zhenying Wu Wenjia Lu Jinli Han Yanbo Chen Yan Chen Peixiang Ni Ying Wang Xun Xu Ying Huang Chi Song Zhiwen Wang Nan Shi Xudong Zhang Xiaohua Fang Qing Yang Huawu Jiang Yaping Chen Meiru Li Ying Wang Fan Chen Jun Wang Guojiang Wu 《The Plant journal : for cell and molecular biology》2015,81(5):810-821
The family Euphorbiaceae includes some of the most efficient biomass accumulators. Whole genome sequencing and the development of genetic maps of these species are important components in molecular breeding and genetic improvement. Here we report the draft genome of physic nut (Jatropha curcas L.), a biodiesel plant. The assembled genome has a total length of 320.5 Mbp and contains 27 172 putative protein‐coding genes. We established a linkage map containing 1208 markers and anchored the genome assembly (81.7%) to this map to produce 11 pseudochromosomes. After gene family clustering, 15 268 families were identified, of which 13 887 existed in the castor bean genome. Analysis of the genome highlighted specific expansion and contraction of a number of gene families during the evolution of this species, including the ribosome‐inactivating proteins and oil biosynthesis pathway enzymes. The genomic sequence and linkage map provide a valuable resource not only for fundamental and applied research on physic nut but also for evolutionary and comparative genomics analysis, particularly in the Euphorbiaceae. 相似文献
72.
Zachary L. Fuller Elina L. Ni?o Harland M. Patch Oscar C. Bedoya-Reina Tracey Baumgarten Elliud Muli Fiona Mumoki Aakrosh Ratan John McGraw Maryann Frazier Daniel Masiga Stephen Schuster Christina M. Grozinger Webb Miller 《BMC genomics》2015,16(1)
Background
With the development of inexpensive, high-throughput sequencing technologies, it has become feasible to examine questions related to population genetics and molecular evolution of non-model species in their ecological contexts on a genome-wide scale. Here, we employed a newly developed suite of integrated, web-based programs to examine population dynamics and signatures of selection across the genome using several well-established tests, including FST, pN/pS, and McDonald-Kreitman. We applied these techniques to study populations of honey bees (Apis mellifera) in East Africa. In Kenya, there are several described A. mellifera subspecies, which are thought to be localized to distinct ecological regions.Results
We performed whole genome sequencing of 11 worker honey bees from apiaries distributed throughout Kenya and identified 3.6 million putative single-nucleotide polymorphisms. The dense coverage allowed us to apply several computational procedures to study population structure and the evolutionary relationships among the populations, and to detect signs of adaptive evolution across the genome. While there is considerable gene flow among the sampled populations, there are clear distinctions between populations from the northern desert region and those from the temperate, savannah region. We identified several genes showing population genetic patterns consistent with positive selection within African bee populations, and between these populations and European A. mellifera or Asian Apis florea.Conclusions
These results lay the groundwork for future studies of adaptive ecological evolution in honey bees, and demonstrate the use of new, freely available web-based tools and workflows (http://usegalaxy.org/r/kenyanbee) that can be applied to any model system with genomic information.Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-1712-0) contains supplementary material, which is available to authorized users. 相似文献73.
74.
75.
Yu?Ni Zhengyuan?Sun Xianzhi?Huang Chuanshu?Huang Yanjun?GuoEmail author 《Acta Physiologiae Plantarum》2015,37(6):112
Though mulberry (Morus alba) tree shows great adaptations to various climate conditions, their leaf water status and photosynthesis are sensitive to climate changes. In the current study, seven widely planted mulberry cultivars in Chongqing, Southwest China, were selected to analyze leaf cuticular wax characteristics, gas exchange index, post-harvest leaf water status and their relationships, aiming to provide new theory in screening high resistant mulberry cultivars. Mulberry trees formed rounded cap-type idioblasts on the adaxial leaf surface. Film-like waxes and granule-type wax crystals covered leaf surfaces, varying in crystal density among cultivars. The stomatal aperture on the abaxial surface of cultivars with high wax amount was smaller than that of cultivars with low wax amount. The amount of total wax was negatively correlated with the net photosynthetic rate (P N), transpiration rate (E) and stomatal conductance (g s) and positively correlated with the moisture retention capacity. It suggested that both cuticular wax and stomatal factor might be involved in regulating water loss in mulberry leaves under field conditions. The variability in moisture retention capacity and cuticular wax characteristics might be important in evaluating and screening mulberry cultivars for increasing silk quality and silkworm productivity. 相似文献
76.
77.
78.
Increasing reports suggest that deregulated microRNAs (miRNAs) might provide novel therapeutic targets for cancers. However, the expression and function of miR-300 in osteosarcoma is still unknown. In our study, we found that the expression of miR-300 was up-regulated in osteosarcoma tissues and cells compared with paired adjacent non-tumor bone tissues and osteoblastic cells using RT-qPCR. The enforced expression of miR-300 could promote cell proliferation, invasion and epithelial-mesenchymal transition (EMT). Moreover, we identified that bromodomain-containing protein 7 (BRD7), a new tumor suppressor gene, was a direct target of miR-300. Ectopic expression of BRD7 could significantly inhibit miR-300-promoted proliferation, invasion and EMT. Therefore, our results identify an important role for miR-300 in osteosarcoma through regulating BRD7 expression. 相似文献
79.
80.
Digital image analysis of expansion growth of cultured cotton ovules with fibers and their responses to ABA 总被引:1,自引:0,他引:1
Ling Fan Meng Lü Zhi-Yong Ni Wen-Ran Hu Juan Wang 《In vitro cellular & developmental biology. Plant》2011,47(3):369-374
Cotton ovule cultures have obvious advantages over whole plants when experimental protocols call for inhibitors, radio-labeled
precursors or controlled environmental conditions to be tested. The responses of ovule expansion growth and attached fiber
elongation to external factors require accurate measurement techniques. This paper presents a new method for digital image
analysis of the growth area of cotton ovules with fibers at high resolution. The method was characterized under constant conditions
and during dynamic responses to different levels of ABA (abscisic acid) treatment. The growth area was treated as area occupied
within the outline of the Petri dish image of the growing ovule with fibers. Growth area increase showed the same trends as
fiber length increase and was significantly correlated with the fiber length increase under different levels of ABA treatment
(r
2 = 0.97). This new analysis method provides a simple, noninvasive, and more accurate approach for growth analysis in the cotton
ovule culture system. Using this method, the effects of ABA on expansion growth of ovule with fibers were characterized. 相似文献