全文获取类型
收费全文 | 1619篇 |
免费 | 135篇 |
国内免费 | 185篇 |
出版年
2024年 | 10篇 |
2023年 | 45篇 |
2022年 | 80篇 |
2021年 | 143篇 |
2020年 | 78篇 |
2019年 | 112篇 |
2018年 | 99篇 |
2017年 | 74篇 |
2016年 | 81篇 |
2015年 | 133篇 |
2014年 | 130篇 |
2013年 | 143篇 |
2012年 | 140篇 |
2011年 | 109篇 |
2010年 | 41篇 |
2009年 | 48篇 |
2008年 | 54篇 |
2007年 | 50篇 |
2006年 | 47篇 |
2005年 | 29篇 |
2004年 | 23篇 |
2003年 | 31篇 |
2002年 | 28篇 |
2001年 | 23篇 |
2000年 | 22篇 |
1999年 | 19篇 |
1998年 | 12篇 |
1997年 | 17篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1982年 | 3篇 |
1980年 | 3篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1970年 | 3篇 |
1968年 | 2篇 |
排序方式: 共有1939条查询结果,搜索用时 203 毫秒
101.
Changtian Pan Dandan Yang Xiaolin Zhao Chen Jiao Yanqiu Yan Anthony Tumbeh Lamin‐Samu Qiaomei Wang Xiangyang Xu Zhangjun Fei Gang Lu 《Plant, cell & environment》2019,42(4):1205-1221
High temperature (HT) is becoming an increasingly serious factor in limiting crop production with global climate change. During hot seasons, owing to prevailing HT, cultivated tomatoes are prone to exhibiting stigma exsertion, which hampers pollination and causes fruit set failure. However, the underlying regulatory mechanisms of the HT‐induced stigma exsertion remain largely unknown. Here, we demonstrate that stigma exsertion induced by HT in cultivated tomato is caused by more seriously shortened stamens than pistils, which is different from the stigma exsertion observed in wild tomato species. Under the HT condition, the different responses of pectin, sugar, expansin, and cyclin cause cell wall remodelling and differentially localized cell division and selective cell enlargement, which further determine the lengths of stamens and pistils. In addition, auxin and jasmonate (JA) are implicated in regulating cell division and cell expansion in stamens and pistils, and exogenous JA instead of auxin treatment can effectively rescue tomato stigma exsertion through regulating the JA/COI1 signalling pathway. Our findings provide a better understanding of stigma exsertions under the HT condition in tomato and uncover a new function of JA in improving plant abiotic stress tolerance. 相似文献
102.
Yue Zhao Meinan Ouyang Yabing Xiong Dandan Wang Haoming Guo Zhonghua Yang 《Chirality》2019,31(3):230-235
Paclobutrazol (PBZ) is a kind of chiral pesticide, which is a plant growth regulator and has fungicidal activity. Because of the steric‐hindrance effect, there are two enantiomers (2S, 3S; 2R, 3R) in the production. This research studied on the dissipation behavior of chiral pesticide PBZ in the brine during the Chinese cabbage pickled process by phase column‐high performance liquid chromatography (HPLC). The result demonstrated the PBZ enantiomers had the different dissipation in the brine. The study on the behavior of chiral pesticide PBZ in food may provide more sufficient data and information for understanding the potential risk in food and evaluating the environmental pollution at the enantiomer level. 相似文献
103.
Weiguo Wang Zhengguang Wang Shijie Chen Xiaofang Zang Jinglei Miao 《Journal of cellular biochemistry》2019,120(2):1763-1772
So far, microRNA has attracted plenty of interest due to its role in tumorigenesis. Reportedly, miR-181b may be involved in the tumorigenesis of osteosarcoma (OS). In the current study, we attempted to investigate the detailed function and mechanism of miR-181b in OS carcinogenesis. Herein, miR-181a, miR-181b, miR-181c, and miR-181d expressions in OS tissues were higher than that in nontumor tissue samples as examined real-time polymerase chain reaction. Via direct targeting, miR-181b negatively regulated the expression of phosphatase and tensin homolog (PTEN), a well-known tumor suppressor. Furthermore, a small interfering RNA strategy was used to find that interleukin (IL)-1B and nuclear factor-κB (NF-κB) regulate miR-181b and PTEN expression. Consequently, the repression of PTEN by miR-181b promotes OS cell proliferation. In summary, our data support a critical role for NF-κB-dependent upregulation of miR-181b, which further inhibited PTEN expression and promoted the cell proliferation of OS cell lines. The above findings represent a new pathway for the repression of PTEN and the promotion of cell proliferation upon IL-1β induction. 相似文献
104.
105.
Sile Liu Weiyuan Wang Yue Ning Hongmei Zheng Yuting Zhan Haihua Wang Yang Yang Jiadi Luo Qiuyuan Wen Hongjing Zang Jinwu Peng Jian Ma Songqing Fan 《Cell death & disease》2022,13(2)
Everolimus is a kind of mammalian target of rapamycin (mTOR) inhibitors. Activated mitogen-activated protein kinase interacting kinases/eukaryotic translation initiation factor 4E (MNK/eIF4E) axis plays a crucial role in resistance to Everolimus in non-small cell lung cancer (NSCLC). The eIF4E phosphorylation increased by mTOR inhibitors is mainly mediated by MNKs. However, the mechanisms are poorly understood. Recently, extensive reprogramming of miRNA profiles has also been found after long-term mTOR inhibitor exposure. Our previous studies have confirmed that tumor suppressor miR-7-5p is decreased in A549 cells after treatment with Everolimus. Exactly, MNK1 is the target of miR-7-5p. In this study, we investigated the biological functions and potential molecular mechanisms of miR-7-5p in the NSCLC undergoing treatment with Everolimus. We confirmed that Everolimus targeted mTORC1 inducing NSCLC cells to secrete miR-7-5p-loaded exosomes in Rab27A and Rab27B-dependent manners. Loss of intracellular miR-7-5p induced phosphorylation of MNK/eIF4E axis, but a supplement of extra exosomal miR-7-5p could reverse it. Of note, both low expression of miR-7-5p and elevated MNK1 protein were associated with a poor prognosis of NSCLC. Both endogenous miR-7-5p and exo-miR-7-5p enhanced the therapeutic efficacy of Everolimus by inhibiting the proliferation, migration, and metastasis of NSCLC in vitro and in vivo. The combination of miR-7-5p with Everolimus induced apoptosis to exhibit a synergistic anticancer therapeutic efficacy through dual abrogation of MNK/eIF4E and mTOR in NSCLC. In conclusion, Everolimus decreases the intracellular miR-7-5p by releasing of miR-7-5p loaded exosomes from NSCLC cells in Rab27A and Rab27B dependent manners. Either endogenous miR-7-5p or exo-miR-7-5p combined with Everolimus can enhance the anticancer efficacy by targeting MNK/eIF4E axis and mTOR. Besides, both low levels of miR-7-5p and positive expression of MNK1 act as independent poor prognostic biomarkers for NSCLC. Therefore, restoring miR-7-5p carried by exosome may be a promising novel combined therapeutic strategy with Everolimus for NSCLC.Subject terms: Drug development, Growth factor signalling, Oncogenesis 相似文献
106.
Changchun Shao Yingying Jing Shanmin Zhao Xue Yang Yiming Hu Yan Meng Yihua Huang Fei Ye Lu Gao Wenting Liu Dandan Sheng Rong Li Xiaoren Zhang Lixin Wei 《Cell death & disease》2022,13(3)
Recent reports have demonstrated that Sox9+HNF4α+ hepatocytes are involved in liver regeneration after chronic liver injury; however, little is known about the origin of Sox9+HNF4α+ hepatocytes and the regulatory mechanism. Employing a combination of chimeric lineage tracing, immunofluorescence, and immunohistochemistry, we demonstrate that Sox9+HNF4α+ hepatocytes, generated by transition from mature hepatocytes, play an important role in the initial phase after partial hepatectomy (PHx). Additionally, knocking down the expression of Sox9 suppresses hepatocyte proliferation and blocks the recovery of lost hepatic tissue. In vitro and in vivo assays demonstrated that Bcl3, activated by LPS, promotes hepatocyte conversion and liver regeneration. Mechanistically, Bcl3 forms a complex with and deubiquitinates YAP1 and further induces YAP1 to translocate into the nucleus, resulting in Sox9 upregulation and mature hepatocyte conversion. We demonstrate that Bcl3 promotes Sox9+HNF4α+ hepatocytes to participate in liver regeneration, and might therefore be a potential target for enhancing regeneration after liver injury.Subject terms: Ubiquitylation, Transdifferentiation, NF-kappaB, Regeneration, Stem-cell research 相似文献
107.
108.
Xuelei Zang Weixin Ke Lifeng Wang Hua Wu Yemei Huang Hengyu Deng Meng Zhou Ningxin Wu Xinying Xue Dingxia Shen 《PLoS neglected tropical diseases》2022,16(2)
Cryptococcus gattii (C. gattii) is a fungal pathogen that once caused an outbreak of cryptococcosis on Vancouver Island, and had spread worldwide, while few data were available in China. In this study, seven clinical isolates of C. gattii VGII were collected from 19 hospitals, Multi-locus Sequence Typing (MLST) analysis and whole-genome sequencing (WGS) was performed, combined with published data for phylogenetic analysis. In addition, in vitro antifungal susceptibility testing, phenotypic analysis, and in vivo virulence studies were performed, subsequently, histopathological analysis of lung tissue was performed. C.gattii VGII infected patients were mainly immunocompetent male, and most of them had symptoms of central nervous system (CNS) involvement. MLST results showed that isolates from China exhibited high genetic diversity, and sequence type (ST) 7 was the major ST among the isolates. Some clinical isolates showed a close phylogenetic relationship with strains from Australia and South America. All clinical isolates did not show resistance to antifungal drugs. In addition, there was no correlation between virulence factors (temperature, melanin production, and capsule size) and virulence while in vivo experiments showed significant differences in virulence among strains. Lung fungal burden and damage to lung tissue correlated with virulence, and degree of damage to lung tissue in mice may highlight differences in virulence. Our work seeks to provide useful data for molecular epidemiology, antifungal susceptibility, and virulence differences of C. gattii VGII in China. 相似文献
109.
2005年5~9月,在长春市吉林农业大学校园内的杨树林和李树林内进行人工挂放柞蚕Antheraea pernyi Guerin-Meneville卵卡诱集本地平腹小蜂Anastatus spp.寄生试验.结果表明杨树林中的舞毒蛾卵平腹小蜂Anastatus japonicus Ashmead的寄生率最高可达23.1%,李树林中的舞毒蛾卵平腹小蜂的寄生率最高可达33.5%,李树林中舞毒蛾卵平腹小蜂的寄生率明显高于杨树林.全年中,舞毒蛾卵平腹小蜂分别在6月下旬和8月上旬出现2次寄生高峰. 相似文献
110.