全文获取类型
收费全文 | 5997篇 |
免费 | 586篇 |
国内免费 | 652篇 |
出版年
2024年 | 21篇 |
2023年 | 85篇 |
2022年 | 233篇 |
2021年 | 337篇 |
2020年 | 237篇 |
2019年 | 289篇 |
2018年 | 291篇 |
2017年 | 226篇 |
2016年 | 274篇 |
2015年 | 411篇 |
2014年 | 460篇 |
2013年 | 456篇 |
2012年 | 592篇 |
2011年 | 503篇 |
2010年 | 304篇 |
2009年 | 309篇 |
2008年 | 309篇 |
2007年 | 280篇 |
2006年 | 211篇 |
2005年 | 219篇 |
2004年 | 208篇 |
2003年 | 179篇 |
2002年 | 153篇 |
2001年 | 115篇 |
2000年 | 96篇 |
1999年 | 76篇 |
1998年 | 61篇 |
1997年 | 52篇 |
1996年 | 37篇 |
1995年 | 31篇 |
1994年 | 35篇 |
1993年 | 21篇 |
1992年 | 30篇 |
1991年 | 29篇 |
1990年 | 11篇 |
1989年 | 12篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 1篇 |
排序方式: 共有7235条查询结果,搜索用时 15 毫秒
61.
Yang Xiangdong Yang Jing Li Haiyun Niu Lu Xing Guojie Zhang Yuanyu Xu Wenjing Zhao Qianqian Li Qiyun Dong Yingshan 《Transgenic research》2020,29(2):187-198
Transgenic Research - Pathogenic fungi represent one of the major biotic stresses for soybean production across the world. Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot, is a... 相似文献
62.
Yi‐Ying Liao Yu Liu Xing Liu Tian‐Feng Lü Ruth Wambui Mbichi Tao Wan Fan Liu 《Ecology and evolution》2020,10(6):3090-3102
Myriophyllum, among the most species‐rich genera of aquatic angiosperms with ca. 68 species, is an extensively distributed hydrophyte lineage in the cosmopolitan family Haloragaceae. The chloroplast (cp) genome is useful in the study of genetic evolution, phylogenetic analysis, and molecular dating of controversial taxa. Here, we sequenced and assembled the whole chloroplast genome of Myriophyllum spicatum L. and compared it to other species in the order Saxifragales. The complete chloroplast genome sequence of M. spicatum is 158,858 bp long and displays a quadripartite structure with two inverted repeats (IR) separating the large single copy (LSC) region from the small single copy (SSC) region. Based on sequence identification and the phylogenetic analysis, a 4‐kb phylogenetically informative inversion between trnE‐trnC in Myriophyllum was determined, and we have placed this inversion on a lineage specific to Myriophyllum and its close relatives. The divergence time estimation suggested that the trnE‐trnC inversion possibly occurred between the upper Cretaceous (72.54 MYA) and middle Eocene (47.28 MYA) before the divergence of Myriophyllum from its most recent common ancestor. The unique 4‐kb inversion might be caused by an occurrence of nonrandom recombination associated with climate changes around the K‐Pg boundary, making it interesting for future evolutionary investigations. 相似文献
63.
Achyut Kumar Banerjee Wuxia Guo Sitan Qiao Weixi Li Fen Xing Yuting Lin Zhuangwei Hou Sen Li Ying Liu Yelin Huang 《Ecology and evolution》2020,10(14):7349-7363
Phylogeographic forces driving evolution of sea‐dispersed plants are often influenced by regional and species characteristics, although not yet deciphered at a large spatial scale for many taxa like the mangrove species Heritiera littoralis. This study aimed to assess geographic distribution of genetic variation of this widespread mangrove in the Indo‐West Pacific region and identify the phylogeographic factors influencing its present‐day distribution. Analysis of five chloroplast DNA fragments’ sequences from 37 populations revealed low genetic diversity at the population level and strong genetic structure of H. littoralis in this region. The estimated divergence times between the major genetic lineages indicated that glacial level changes during the Pleistocene epoch induced strong genetic differentiation across the Indian and Pacific Oceans. In comparison to the strong genetic break imposed by the Sunda Shelf toward splitting the lineages of the Indian and Pacific Oceans, the genetic differentiation between Indo‐Malesia and Australasia was not so prominent. Long‐distance dispersal ability of H. littoralis propagules helped the species to attain transoceanic distribution not only across South East Asia and Australia, but also across the Indian Ocean to East Africa. However, oceanic circulation pattern in the South China Sea was found to act as a barrier creating further intraoceanic genetic differentiation. Overall, phylogeographic analysis in this study revealed that glacial vicariance had profound influence on population differentiation in H. littoralis and caused low genetic diversity except for the refugia populations near the equator which might have persisted through glacial maxima. With increasing loss of suitable habitats due to anthropogenic activities, these findings therefore emphasize the urgent need for conservation actions for all populations throughout the distribution range of H. littoralis. 相似文献
64.
65.
Chen Han-Wen Zhang Xiao-Xia Peng Zhu-Ding Xing Zu-Min Zhang Yi-Wen Li Ya-Lan 《Molecular and cellular biochemistry》2021,476(4):1751-1763
Molecular and Cellular Biochemistry - Treatment of bone cancer pain (BCP) caused by bone metastasis in advanced cancers remains a challenge in clinical oncology, and the underlying mechanisms of... 相似文献
66.
Molecular and Cellular Biochemistry - Xp11 translocation renal cell carcinoma (tRCC) characterized by the rearrangement of the TFE3 is recently identified as a unique subtype of RCC that urgently... 相似文献
67.
68.
Yang Jing Xun HongWei Niu Lu He Hongli Cheng Yunqing Zhong Xiaofang Zhao Qianqian Xing Guojie Liu Jianfeng Yang Xiangdong 《Transgenic research》2021,30(5):675-686
Transgenic Research - Soybean seeds are an ideal host for the production of recombinant proteins because of their high content of proteins, long-term stability of seed proteins under ambient... 相似文献
69.
随着全球塑料循环体系的变革升级,提高塑料的回收利用不仅可以减少塑料在生命周期中的碳排放,还可以解决废塑料潜在的生态环境危害。文中介绍了2019年国家自然科学基金组织间国际 (地区) 合作研究项目“废塑料资源高效生物降解转化的关键科学问题与技术 (MIXed plastics biodegradation and UPcycling using microbial communities,MIX-UP)”。该项目聚焦“塑料污染”这一全球化的问题,围绕中欧双方确定的“塑料生物降解菌群”研究领域,联合中欧双方14家优势科研单位,开展实质性的重大前沿合作研究。针对废塑料生物降解中存在的解聚与重塑两个难题,项目以难降解石油基塑料 (PP、PE、PUR、PET和PS) 以及生物可降解塑料 (PLA和PHA) 的混合废塑料作为研究对象,从塑料微生物降解途径解析及关键元件的挖掘与改造、塑料高效降解混菌/多酶体系的构建与功能调控、塑料降解物的高值化炼制途径设计与利用策略3个方面展开研究。本项目将突破废塑料生物降解转化中高效降解元件挖掘、塑料降解物高值化利用的关键科学问题与技术,探索一条废塑料资源化、高值化、循环化、低碳化的新塑料循环路线,建立以“降塑再造”为核心理念的废塑料生物炼制体系,丰富我国固废资源化生物技术利用平台。项目的实施不仅有助于提升我国塑料 (生物) 循环经济的理论基础和关键技术水平,还可以推动我国与国际科研院所的多边交流与合作,促进我国在生物技术领域的创新发展,助力我国碳中和目标的实现。 相似文献
70.