全文获取类型
收费全文 | 11138篇 |
免费 | 828篇 |
国内免费 | 789篇 |
出版年
2024年 | 15篇 |
2023年 | 146篇 |
2022年 | 370篇 |
2021年 | 703篇 |
2020年 | 393篇 |
2019年 | 495篇 |
2018年 | 432篇 |
2017年 | 339篇 |
2016年 | 485篇 |
2015年 | 747篇 |
2014年 | 865篇 |
2013年 | 840篇 |
2012年 | 1073篇 |
2011年 | 847篇 |
2010年 | 522篇 |
2009年 | 483篇 |
2008年 | 520篇 |
2007年 | 497篇 |
2006年 | 394篇 |
2005年 | 371篇 |
2004年 | 289篇 |
2003年 | 261篇 |
2002年 | 190篇 |
2001年 | 208篇 |
2000年 | 150篇 |
1999年 | 163篇 |
1998年 | 96篇 |
1997年 | 109篇 |
1996年 | 114篇 |
1995年 | 101篇 |
1994年 | 107篇 |
1993年 | 66篇 |
1992年 | 67篇 |
1991年 | 85篇 |
1990年 | 54篇 |
1989年 | 43篇 |
1988年 | 25篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 23篇 |
1984年 | 14篇 |
1983年 | 17篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
Xiaoning Fan Xianrong Che Wenzhen Lai Sijia Wang Wentao Hu Hui Chen Bin Zhao Ming Tang Xianan Xie 《Environmental microbiology》2020,22(6):2053-2079
Phosphorus is a macronutrient that is essential for plant survival. Most land plants have evolved the ability to form a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi, which enhances phosphate (Pi) acquisition. Modulation of Pi transporter systems is the master strategy used by mycorrhizal plants to adapt to ambient Pi concentrations. However, the specific functions of PHOSPHATE TRANSPORTER 1 (PHT1) genes, which are Pi transporters that are responsive to high Pi availability, are largely unknown. Here, we report that AsPT5, an Astragalus sinicus (Chinese milk vetch) member of the PHT1 gene family, is conserved across dicotyledons and is constitutively expressed in a broad range of tissues independently of Pi supply, but is remarkably induced by indole-3-acetic acid (auxin) treatment under moderately high Pi conditions. Subcellular localization experiments indicated that AsPT5 localizes to the plasma membrane of plant cells. Using reverse genetics, we showed that AsPT5 not only mediates Pi transport and remodels root system architecture but is also essential for arbuscule formation in A. sinicus under moderately high Pi concentrations. Overall, our study provides insight into the function of AsPT5 in Pi transport, AM development and the cross-talk between Pi nutrition and auxin signalling in mycorrhizal plants. 相似文献
152.
Yingfan Cai Xiaoyan Cai Qinglian Wang Ping Wang Yu Zhang Chaowei Cai Yanchao Xu Kunbo Wang Zhongli Zhou Chenxiao Wang Shuaipeng Geng Bo Li Qi Dong Yuqing Hou Heng Wang Peng Ai Zhen Liu Feifei Yi Minshan Sun Guoyong An Jieru Cheng Yuanyuan Zhang Qian Shi Yuanhui Xie Xinying Shi Ying Chang Feifei Huang Yun Chen Shimiao Hong Lingyu Mi Quan Sun Lin Zhang Baoliang Zhou Renhai Peng Xiao Zhang Fang Liu 《Plant biotechnology journal》2020,18(3):814-828
153.
154.
Genome assembly provides insights into the genome evolution and flowering regulation of orchardgrass
155.
Shi Zhenjie Zheng Qianjiao Sun Xiaoyang Xie Fuchun Zhao Jian Zhang Gaoyun Zhao Wei Guo Zhixin Ariunzul Ariuka Fahad Shah Adnan Muhammad Qin Dong Saud Shah Yajun Chen 《BMC plant biology》2020,20(1):1-15
Kernel weight and morphology are important traits affecting cereal yields and quality. Dissecting the genetic basis of thousand kernel weight (TKW) and its related traits is an effective method to improve wheat yield. In this study, we performed quantitative trait loci (QTL) analysis using recombinant inbred lines derived from the cross ‘PuBing3228 × Gao8901’ (PG-RIL) to dissect the genetic basis of kernel traits. A total of 17 stable QTLs related to kernel traits were identified, notably, two stable QTLs QTkw.cas-1A.2 and QTkw.cas-4A explained the largest portion of the phenotypic variance for TKW and kernel length (KL), and the other two stable QTLs QTkw.cas-6A.1 and QTkw.cas-7D.2 contributed more effects on kernel width (KW). Conditional QTL analysis revealed that the stable QTLs for TKW were mainly affected by KW. The QTLs QTkw.cas-7D.2 and QKw.cas-7D.1 associated with TKW and KW were delimited to the physical interval of approximately 3.82 Mb harboring 47 candidate genes. Among them, the candidate gene TaFT-D1 had a 1 bp insertions/deletion (InDel) within the third exon, which might be the reason for diversity in TKW and KW between the two parents. A Kompetitive Allele-Specific PCR (KASP) marker of TaFT-D1 allele was developed and verified by PG-RIL and a natural population consisted of 141 cultivar/lines. It was found that the favorable TaFT-D1 (G)-allele has been positively selected during Chinese wheat breeding. Thus, these results can be used for further positional cloning and marker-assisted selection in wheat breeding programs. Seventeen stable QTLs related to kernel traits were identified. The stable QTLs for thousand kernel weight were mainly affected by kernel width. TaFT-D1 could be the candidate gene for QTLs QTkw.cas-7D.2 and QKw.cas-7D.1. 相似文献
156.
Yao Dang Yongpan An Jinzhao He Boyue Huang Jie Zhu Miaomiao Gao Shun Zhang Xin Wang Baoxue Yang Zhengwei Xie 《Aging cell》2020,19(1)
Although aging and senescence have been extensively studied in the past few decades, however, there is lack of clinical treatment available for anti‐aging. This study presents the effects of berberine (BBR) on the aging process resulting in a promising extension of lifespan in model organisms. BBR extended the replicative lifespan, improved the morphology, and boosted rejuvenation markers of replicative senescence in human fetal lung diploid fibroblasts (2BS and WI38). BBR also rescued senescent cells with late population doubling (PD). Furthermore, the senescence‐associated β‐galactosidase (SA‐β‐gal)‐positive cell rates of late PD cells grown in the BBR‐containing medium were ~72% lower than those of control cells, and its morphology resembled that of young cells. Mechanistically, BBR improved cell growth and proliferation by promoting entry of cell cycles from the G0 or G1 phase to S/G2‐M phase. Most importantly, BBR extended the lifespan of chemotherapy‐treated mice and naturally aged mice by ~52% and ~16.49%, respectively. The residual lifespan of the naturally aged mice was extended by 80%, from 85.5 days to 154 days. The oral administration of BBR in mice resulted in significantly improved health span, fur density, and behavioral activity. Therefore, BBR may be an ideal candidate for the development of an anti‐aging medicine. 相似文献
157.
Zhongli Shi Kaixia Zhang Huimin Zhou Lei Jiang Bing Xie Ruiyuan Wang Wenzhen Xia Yajuan Yin Zhaoyu Gao Dongsheng Cui Rui Zhang Shunjiang Xu 《Aging cell》2020,19(3)
Alzheimer's disease (AD) and cancer have inverse relationship in many aspects. Some tumor suppressors, including miR‐34c, are decreased in cancer but increased in AD. The upstream regulatory pathways and the downstream mechanisms of miR‐34c in AD remain to be investigated. The expression of miR‐34c was detected by RT–qPCR in oxidative stressed neurons, hippocampus of SAMP8 mice, or serum of patients with amnestic mild cognitive impairment (aMCI). Dual luciferase assay was performed to confirm the binding sites of miR‐34c in its target mRNA. The Morris water maze (MWM) was used to evaluate learning and memory in SAMP8 mice administrated with miR‐34c antagomir (AM34c). Golgi staining was used to evaluate the synaptic function and structure. The dramatically increased miR‐34c was mediated by ROS‐JNK‐p53 pathway and negatively regulated synaptotagmin 1 (SYT1) expression by targeting the 3′‐untranslated region (3′‐UTR) of syt1 in AD. The expression of SYT1 protein was reduced by over expression of miR‐34c in the HT‐22 cells and vice versa. Administration of AM34c by the third ventricle injection or intranasal delivery markedly increased the brain levels of SYT1 and ameliorated the cognitive function in SAMP8 mice. The serum miR‐34c was significantly increased in patients with aMCI and might be a predictive biomarker for diagnosis of aMCI. These results indicated that increased miR‐34c mediated synaptic and memory deficits by targeting SYT1 through ROS‐JNK‐p53 pathway and the miR‐34c/SYT1 pathway could be considered as a promising novel therapeutic target for patients with AD. 相似文献
158.
159.
Gang Fan Mario Kaßmann Yingqiu Cui Claudia Matthaeus Sverine Kunz Cheng Zhong Shuai Zhu Yu Xie Dmitry Tsvetkov Oliver Daumke Yu Huang Maik Gollasch 《Aging cell》2020,19(4)
Caveolae position CaV3.2 (T‐type Ca2+ channel encoded by the α‐3.2 subunit) sufficiently close to RyR (ryanodine receptors) for extracellular Ca2+ influx to trigger Ca2+ sparks and large‐conductance Ca2+‐activated K+ channel feedback in vascular smooth muscle. We hypothesize that this mechanism of Ca2+ spark generation is affected by age. Using smooth muscle cells (VSMCs) from mouse mesenteric arteries, we found that both Cav3.2 channel inhibition by Ni2+ (50 µM) and caveolae disruption by methyl‐ß‐cyclodextrin or genetic abolition of Eps15 homology domain‐containing protein (EHD2) inhibited Ca2+ sparks in cells from young (4 months) but not old (12 months) mice. In accordance, expression of Cav3.2 channel was higher in mesenteric arteries from young than old mice. Similar effects were observed for caveolae density. Using SMAKO Cav1.2?/? mice, caffeine (RyR activator) and thapsigargin (Ca2+ transport ATPase inhibitor), we found that sufficient SR Ca2+ load is a prerequisite for the CaV3.2‐RyR axis to generate Ca2+ sparks. We identified a fraction of Ca2+ sparks in aged VSMCs, which is sensitive to the TRP channel blocker Gd3+ (100 µM), but insensitive to CaV1.2 and CaV3.2 channel blockade. Our data demonstrate that the VSMC CaV3.2‐RyR axis is down‐regulated by aging. This defective CaV3.2‐RyR coupling is counterbalanced by a Gd3+ sensitive Ca2+ pathway providing compensatory Ca2+ influx for triggering Ca2+ sparks in aged VSMCs. 相似文献
160.