全文获取类型
收费全文 | 881篇 |
免费 | 67篇 |
国内免费 | 45篇 |
出版年
2024年 | 4篇 |
2023年 | 10篇 |
2022年 | 22篇 |
2021年 | 47篇 |
2020年 | 29篇 |
2019年 | 36篇 |
2018年 | 28篇 |
2017年 | 23篇 |
2016年 | 38篇 |
2015年 | 59篇 |
2014年 | 55篇 |
2013年 | 66篇 |
2012年 | 66篇 |
2011年 | 65篇 |
2010年 | 19篇 |
2009年 | 31篇 |
2008年 | 41篇 |
2007年 | 27篇 |
2006年 | 37篇 |
2005年 | 24篇 |
2004年 | 17篇 |
2003年 | 26篇 |
2002年 | 24篇 |
2001年 | 21篇 |
2000年 | 20篇 |
1999年 | 19篇 |
1998年 | 11篇 |
1997年 | 17篇 |
1996年 | 10篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 7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993条查询结果,搜索用时 15 毫秒
41.
Developing new ABX3‐type perovskites is very important for expanding the family of perovskites and obtaining excellent light absorbing material. One strategy is replacing A site atoms with super‐alkali atoms for the perovskites, but super‐alkali perovskites with stable dynamics performance and high efficiency have not been found until now. Herein, massive super‐alkalis, such as Li3O, Li2F, H5O2, and so on, are introduced into the cubic CH3NH3PbI3 perovskites, and the perovskites with these super‐alkalis are systematically studied by using ab initio molecular dynamics simulation and density functional theory based first principles calculations. Calculated results indicate that the perovskites with the super‐alkalis including metal atoms show unstable dynamics performance under normal temperature and pressure. On the contrary, the first obtainable super‐alkali perovskites of cubic H5O2MBr3 (M = Ge, Sn, Pb) and H5O2PbI3 show stable dynamics performance. They also show suitable tolerance factors, negative formation energies, tunable direct band gaps, and small effective hole and electron masses. Moreover, the calculated power conversion efficiencies of 23.17% and 22.83% are obtained for the single‐junction solar cells based on the cubic H5O2SnBr3 and H5O2PbBr3 perovskites, respectively. 相似文献
42.
Jiangying Cao Jie Zang Xiujie Kong Chunlong Zhao Ting Chen Yingying Ran Hang Dong Wenfang Xu Yingjie Zhang 《Bioorganic & medicinal chemistry》2019,27(6):978-990
Aminopeptidase N (APN) has been proved to be deeply associated with cancer angiogenesis, metastasis and invasion. Therefore, APN gains increasing attention as a promising anti-tumor target. In the current study, we report the design, synthesis, biological evaluation and structure-activity relationship of one new series of leucine ureido derivatives containing the 1,2,3-triazole moiety. Among them, compound 31f was identified as the best APN inhibitor with IC50 value being two orders of magnitude lower than that of the positive control bestatin. Compound 31f possessed selective cytotoxicity to several tumor cell lines over the normal cell line human umbilical vein endothelial cells (HUVECs). Notably, when combined with 5-fluorouracil (5-Fu), 31f exhibited synergistic anti-proliferation effect against several tumor cell lines. At the same concentration, 31f exhibited much better anti-angiogenesis activities than bestatin in the HUVECs capillary tube formation assay and the rat thoracic aorta rings test. In the in vitro anti-invasion assay, 31f also exhibited superior potency over bestatin. Moreover, considerable in vivo antitumor potencies of 31f alone or in combination with 5-Fu were observed without significant toxic signs in a mouse heptoma H22 tumor transplant model. 相似文献
43.
Si Zhang Zhongnan Yin Fei-Fei Dai Hao Wang Meng-Jiao Zhou Ming-Hui Yang Shu-Feng Zhang Zhi-Feng Fu Ying-Wu Mei Ming-Xi Zang Lixiang Xue 《Journal of cellular physiology》2019,234(8):13252-13262
Although cardiac hypertrophy is widely recognized as a risk factor that leads to cardiac dysfunction and, ultimately, heart failure, the complex mechanisms underlying cardiac hypertrophy remain incompletely characterized. The nuclear receptor peroxisome proliferator-activated receptor δ (PPARδ) is involved in the regulation of cardiac lipid metabolism. Here, we describe a novel PPARδ-dependent molecular cascade involving microRNA-29a (miR-29a) and atrial natriuretic factor (ANF), which is reactivated in cardiac hypertrophy. In addition, we identify a novel role of miR-29a, in which it has a cardioprotective function in isoproterenol hydrochloride-induced cardiac hypertrophy by targeting PPARδ and downregulating ANF. Finally, we provide evidence that miR-29a reduces the isoproterenol hydrochloride-induced cardiac hypertrophy response, thereby underlining the potential clinical relevance of miR-29a in which it may serve as a potent therapeutic target for heart hypertrophy treatment. 相似文献
44.
Liu Jingna Zang Huadong Xu Heshui Zhang Kai Jiang Ying Hu Yuegao Zeng Zhaohai 《Plant and Soil》2019,438(1-2):85-99
Plant and Soil - Moso bamboo (Phyllostachys edulis) invasions into adjacent forests are becoming increasingly common. Moso bamboo invasions affect litter quality, soil nutrients, and microbial... 相似文献
45.
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
46.
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
47.
48.
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
49.
Immune evasion genes from filarial nematodes 总被引:12,自引:0,他引:12
Maizels RM Gomez-Escobar N Gregory WF Murray J Zang X 《International journal for parasitology》2001,31(9):889-898
50.
F H Falcone P Loke X Zang A S MacDonald R M Maizels J E Allen 《Journal of immunology (Baltimore, Md. : 1950)》2001,167(9):5348-5354