全文获取类型
收费全文 | 2667篇 |
免费 | 220篇 |
国内免费 | 1篇 |
专业分类
2888篇 |
出版年
2022年 | 28篇 |
2021年 | 55篇 |
2020年 | 29篇 |
2019年 | 40篇 |
2018年 | 55篇 |
2017年 | 49篇 |
2016年 | 77篇 |
2015年 | 92篇 |
2014年 | 119篇 |
2013年 | 153篇 |
2012年 | 183篇 |
2011年 | 163篇 |
2010年 | 99篇 |
2009年 | 98篇 |
2008年 | 124篇 |
2007年 | 107篇 |
2006年 | 93篇 |
2005年 | 89篇 |
2004年 | 92篇 |
2003年 | 69篇 |
2002年 | 73篇 |
2001年 | 65篇 |
2000年 | 58篇 |
1999年 | 48篇 |
1998年 | 18篇 |
1997年 | 28篇 |
1996年 | 22篇 |
1993年 | 19篇 |
1992年 | 54篇 |
1991年 | 27篇 |
1990年 | 30篇 |
1989年 | 29篇 |
1988年 | 40篇 |
1987年 | 31篇 |
1986年 | 28篇 |
1985年 | 48篇 |
1984年 | 27篇 |
1983年 | 34篇 |
1982年 | 19篇 |
1981年 | 30篇 |
1980年 | 20篇 |
1979年 | 30篇 |
1978年 | 30篇 |
1977年 | 21篇 |
1976年 | 19篇 |
1975年 | 29篇 |
1974年 | 16篇 |
1973年 | 23篇 |
1972年 | 22篇 |
1971年 | 19篇 |
排序方式: 共有2888条查询结果,搜索用时 15 毫秒
101.
102.
Vibrio cholerae hemolysin (HlyA) is a 65?kDa pore-forming toxin which causes lysis of target eukaryotic cells by forming heptameric channels in the plasma membrane. Deletion of the 15?kDa C-terminus β-prism carbohydrate-binding domain generates a 50?kDa truncated variant (HlyA50) with 1000-fold-reduced pore-forming activity. Previously, we showed by cryo-electron microscopy that the two toxin oligomers have central channels, but the 65?kDa toxin oligomer is a seven-fold symmetric structure with bowl-, ring-, and arm-like domains, whereas the 50?kDa oligomer is an asymmetric jar-like heptamer. In the present study, we determined three-dimensional(3D) structures of HlyA and HlyA50 in presence of erythrocyte stroma and observed that interaction of the 65?kDa toxin with the stroma induced a significant decrease in the height of the β-barrel oligomer with a change in conformation of the ring- and arm-like domains of HlyA. These features were absent in interaction of HlyA50 with stroma. We propose that this conformational transition is critical for membrane-insertion of the toxin. 相似文献
103.
Kumar Deepak Jain Ravikumar Shahjahan Banerjee Sabyasachi Prabhu Shriganesh S. Kumar Ranjan Azad Abul K. Roy Chowdhury Dibakar 《Plasmonics (Norwell, Mass.)》2020,15(6):1925-1934
Plasmonics - We present enhancement of operational bandwidths of planar terahertz metasurfaces by incorporating a complex unit cell that consists of a pair of concentric ring resonators. The inner... 相似文献
104.
105.
Bandyopadhyay Arindam Garai Saraswati Banerjee Prajna Paramita Bhattacharya Shelley Chattopadhyay Ansuman 《Molecular biology reports》2021,48(3):2497-2505
Molecular Biology Reports - Globally, breast cancer is a serious concern that exhibits a persistent rise in its incidence and related mortality even after significant advancement in the field of... 相似文献
106.
Erukainure Ochuko L. Salau Veronica F. Atolani Olubunmi Ravichandran Rahul Banerjee Priyanka Preissner Robert Koorbanally Neil A. Islam Md. Shahidul 《Amino acids》2021,53(7):1135-1151
Amino Acids - The antidiabetic effect of l-leucine has been attributed to its modulatory effect on glucose uptake and lipid metabolism in muscles. However, there is a dearth on its effect on... 相似文献
107.
108.
Hanpeng Liao Yudan Bai Chen Liu Chang Wen Qiue Yang Zhi Chen Samiran Banerjee Shungui Zhou Ville-Petri Friman 《Environmental microbiology》2021,23(12):7483-7496
Composting is widely used to reduce the abundance of antibiotic resistance genes (ARGs) in solid waste. While ARG dynamics have been extensively investigated during composting, the fate and abundance of residual ARGs during the storage remain unexplored. Here, we tested experimentally how ARG and mobile genetic element (MGE) abundances change during compost storage using metagenomics, quantitative PCR and direct culturing. We found that 43.8% of ARGs and 39.9% of MGEs quickly recovered already during the first week of storage. This rebound effect was mainly driven by the regrowth of indigenous, antibiotic-resistant bacteria that survived the composting. Bacterial transmission from the surrounding air had a much smaller effect, being most evident as MGE rebound during the later stages of storage. While hyperthermophilic composting was more efficient at reducing the relative abundance of ARGs and MGEs, relatively greater ARG rebound was observed during the storage of hyperthermophilic compost, exceeding the initial levels of untreated sewage sludge. Our study reveals that residual ARGs and MGEs left in the treated compost can quickly rebound during the storage via airborne introduction and regrowth of surviving bacteria, highlighting the need to develop better storage strategies to prevent the rebound of ARGs and MGEs after composting. 相似文献
109.
Minakshi Mazumdar Arghya Adhikary Samik Chakraborty Shravanti Mukherjee Argha Manna Shilpi Saha Suchismita Mohanty Amrita Dutta Pushpak Bhattacharjee Pallab Ray Sreya Chattopadhyay Shuvomoy Banerjee Juni Chakraborty Arun K. Ray Gaurisankar Sa Tanya Das 《Apoptosis : an international journal on programmed cell death》2013,18(5):589-604
Mutations in REarranged during Transfection (RET) receptor tyrosine, followed by the oncogenic activation of RET kinase is responsible for the development of medullary thyroid carcinoma (MTC) that responds poorly to conventional chemotherapy. Targeting RET, therefore, might be useful in tailoring surveillance of MTC patients. Here we showed that theaflavins, the bioactive components of black tea, successfully induced apoptosis in human MTC cell line, TT, by inversely modulating two molecular pathways: (i) stalling PI3K/Akt/Bad pathway that resulted in mitochondrial transmembrane potential (MTP) loss, cytochrome-c release and activation of the executioner caspases-9 and -3, and (ii) upholding p38MAPK/caspase-8/caspase-3 pathway via inhibition of Ras/Raf/ERK. Over-expression of either constitutively active myristoylated-Akt-cDNA (Myr-Akt-cDNA) or dominant-negative-caspase-8-cDNA (Dn-caspase-8-cDNA) partially blocked theaflavin-induced apoptosis, while co-transfection of Myr-Akt-cDNA and Dn-caspase-8-cDNA completely eradicated the effect of theaflavins thereby negating the possibility of existence of other pathways. A search for the upstream signaling revealed that theaflavin-induced disruption of lipid raft caused interference in anchorage of RET in lipid raft that in turn stalled phosphorylation of Ras and PI3Kinase. In such anti-survival cellular micro-environment, pro-apoptotic signals were triggered to culminate into programmed death of MTC cell. These findings not only unveil a hitherto unexplained mechanism underlying theaflavin-induced MTC death, but also validate RET as a promising and potential target for MTC therapy. 相似文献
110.