全文获取类型
收费全文 | 2870篇 |
免费 | 209篇 |
国内免费 | 209篇 |
专业分类
3288篇 |
出版年
2024年 | 5篇 |
2023年 | 44篇 |
2022年 | 120篇 |
2021年 | 192篇 |
2020年 | 111篇 |
2019年 | 129篇 |
2018年 | 119篇 |
2017年 | 115篇 |
2016年 | 155篇 |
2015年 | 196篇 |
2014年 | 213篇 |
2013年 | 249篇 |
2012年 | 273篇 |
2011年 | 246篇 |
2010年 | 150篇 |
2009年 | 120篇 |
2008年 | 150篇 |
2007年 | 115篇 |
2006年 | 89篇 |
2005年 | 72篇 |
2004年 | 63篇 |
2003年 | 49篇 |
2002年 | 42篇 |
2001年 | 32篇 |
2000年 | 24篇 |
1999年 | 29篇 |
1998年 | 17篇 |
1997年 | 20篇 |
1996年 | 24篇 |
1995年 | 12篇 |
1994年 | 20篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1968年 | 3篇 |
排序方式: 共有3288条查询结果,搜索用时 0 毫秒
131.
Zhu Shiyou Liu Ying Zhou Zhuo Zhang Zhiying Xiao Xia Liu Zhiheng Chen Ang Dong Xiaojing Tian Feng Chen Shihua Xu Yiyuan Wang Chunhui Li Qiheng Niu Xuran Pan Qian Du Shuo Xiao Junyu Wang Jianwei Wei Wensheng 《中国科学:生命科学英文版》2022,65(4):701-717
Science China Life Sciences - The outbreak of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has created a global health crisis. SARS-CoV-2 infects varieties of tissues where the known... 相似文献
132.
Shi Ziqi Guan Naiyu Sun Weijiao Sun Tianzhi Niu Lingdi Li Jinyu Ge Junwei 《Probiotics and antimicrobial proteins》2022,14(5):830-844
Probiotics and Antimicrobial Proteins - Although the use of the probiotic bacterium Lactobacillus for the treatment and prevention of diseases caused by various pathogenic bacteria has received... 相似文献
133.
Escherichia coli has been widely used for heterologous protein production (HPP). To determine whether a biofilm environment could benefit E. coli HPP using high copy number plasmids, we compared plasmid maintenance and HPP by E. coli ATCC 33456 containing plasmid pEGFP (a pUC family vector) cultivated in biofilms and in suspended culture. Cells were grown with or without antibiotic selective pressure in flow cells or chemostats for up to 6 days. In biofilms, antibiotic selective pressure increased the plasmid copy number (PCN), but by 144 h, biofilms grown in antibiotic-free media had comparable plasmid concentrations. In the chemostat, the PCN declined steadily, although 100 ppm ampicillin in the medium slowed the rate of plasmid loss. Production of green fluorescent protein (GFP), a representative heterologous protein, was quantified by flow cytometry. In biofilms, at ampicillin concentrations >or=33 ppm, strongly fluorescent cells comprised more than half of the population by 48 h. In the chemostat, more than 50% of the population was non-fluorescent by 48 h in media containing 100 ppm ampicillin, and strongly fluorescent cells were <10% of the population. Biofilm structure was determined by confocal microscopy. Maximum biofilm thickness ranged from 30 to 45 microns, with no significant changes in biofilm structure after 48 h. Plasmid multimer percentages were similar to inocula for cells cultivated in either biofilms or the chemostat. The results indicate that the biofilm environment enhanced both plasmid maintenance and cellular GFP concentrations, and that low levels of antibiotic increased the beneficial effect. 相似文献
134.
Matsui S Satoh H Kawashima H Nagasaka S Niu CF Urushida T Katoh H Watanabe Y Hayashi H 《Canadian journal of physiology and pharmacology》2007,85(2):264-273
Aldosterone has non-genomic effects that express within minutes and modulate intracellular ion milieu and cellular function. However, it is still undefined whether aldosterone actually alters intracellular ion concentrations or cellular contractility. To clarify the non-genomic effects of aldosterone, we measured [Na+]i, Ca2+ transient (CaT), and cell volume in dye-loaded rat ventricular myocytes, and we also evaluated myocardial contractility. We found the following: (i) aldosterone increased [Na+]i at the concentrations of 100 nmol/L to 10 micromol/L; (ii) aldosterone (up to 10 micromol/L) did not alter CaT and cell shortening in isolated myocytes, developed tension in papillary muscles, or left ventricular developed pressure in Langendorff-perfused hearts; (iii) aldosterone (100 nmol/L) increased the cell volume from 47.5 +/- 3.6 pL to 49.8 +/- 3.7 pL (n=8, p<0.05); (iv) both the increases in [Na+]i and cell volume were blocked by a Na+-K+-2Cl- co-transporter (NKCCl) inhibitor, bumetanide, or by a Na+/H+ exchange (NHE) inhibitor, 5-(N-ethyl-N-isopropyl) amiloride; and (v) spironolactone by itself increased in [Na+]i and cell volume. In conclusion, aldosterone rapidly increased [Na+]i and cell volume via NKCC1 and NHE, whereas there were no changes in CaT or myocardial contractility. Hence the non-genomic effects of aldosterone may be related to cell swelling rather than the increase in contractility. 相似文献
135.
Phylogenetic diversity of bacteria isolates from the Qinghai-Tibet Plateau permafrost region 总被引:3,自引:0,他引:3
Zhang G Niu F Ma X Liu W Dong M Feng H An L Cheng G 《Canadian journal of microbiology》2007,53(8):1000-1010
The Qinghai-Tibet Plateau in east Asia is a unique and important permafrost environment. However, its microbiology remains largely unexplored to date. In this study, sediment samples were collected from the Qinghai-Tibet Plateau permafrost region, bacteria isolation procedures were performed 8 times, and the samples incubated at 4 degrees C for nearly 3 months. The number of colony forming units (cfu) ranged from 0 to 10(7)/(g dry soil). The quantity of culturable bacteria grew exponentially within the first few weeks, and then slowed gradually to a plateau. Phylogenetic analyses indicated that all the isolates fell into 6 categories: high G+C Gram-positive bacteria, low G+C Gram-positive bacteria, alpha-Proteobacteria, beta-Proteobacteria, gamma-Proteobacteria, and Cytophaga-Flavobacterium-Bacteroides group bacteria. The isolates belong to 19 genera, but the genera Arthrobacter and Pseudomonas were predominant. With the increase in incubation time, the isolated populations changed in terms of both species and their respective quantities. Of the 33 analyzed isolates, 9 isolates related to 8 genera might be new taxa. These results suggest that the Qinghai-Tibet Plateau permafrost region is a specific ecologic niche that accommodates an original microbial assemblage. 相似文献
136.
Deng-Ke Niu 《Biology direct》2007,2(1):11-9
Background
Accumulating evidence indicates that the nascent RNA can invade and pair with one strand of DNA, forming an R-loop structure that threatens the stability of the genome. In addition, the cost and benefit of introns are still in debate. 相似文献137.
138.
139.
Functional & Integrative Genomics - Stomach adenocarcinoma (STAD) is one of the most commonly diagnosed cancers. This study analyzed the subtypes and characteristics of STAD subtypes by... 相似文献
140.
Chen Yufang Shen Yixin Wang Kuan Qi Yan Niu Wenxin Wang Yan 《Biomechanics and modeling in mechanobiology》2022,21(5):1573-1584
Biomechanics and Modeling in Mechanobiology - Spinal cord injury patients are prone to develop deep tissue injury because of long-term mechanical load. However, there is a lack of statistical... 相似文献