全文获取类型
收费全文 | 5647篇 |
免费 | 426篇 |
国内免费 | 363篇 |
专业分类
6436篇 |
出版年
2024年 | 12篇 |
2023年 | 66篇 |
2022年 | 158篇 |
2021年 | 284篇 |
2020年 | 202篇 |
2019年 | 229篇 |
2018年 | 221篇 |
2017年 | 187篇 |
2016年 | 276篇 |
2015年 | 354篇 |
2014年 | 442篇 |
2013年 | 452篇 |
2012年 | 478篇 |
2011年 | 428篇 |
2010年 | 259篇 |
2009年 | 228篇 |
2008年 | 277篇 |
2007年 | 231篇 |
2006年 | 172篇 |
2005年 | 129篇 |
2004年 | 137篇 |
2003年 | 124篇 |
2002年 | 112篇 |
2001年 | 98篇 |
2000年 | 89篇 |
1999年 | 92篇 |
1998年 | 63篇 |
1997年 | 61篇 |
1996年 | 39篇 |
1995年 | 51篇 |
1994年 | 55篇 |
1993年 | 53篇 |
1992年 | 67篇 |
1991年 | 48篇 |
1990年 | 34篇 |
1989年 | 29篇 |
1988年 | 28篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 22篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 18篇 |
1978年 | 8篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1972年 | 5篇 |
排序方式: 共有6436条查询结果,搜索用时 0 毫秒
991.
Molecular biologic techniques applied to the microbial prospecting of oil and gas in the Ban 876 gas and oil field in China 总被引:3,自引:0,他引:3
Fan Zhang Yuehui She Yong Zheng Zhifeng Zhou Shuqiong Kong Dujie Hou 《Applied microbiology and biotechnology》2010,86(4):1183-1194
Currently, molecular biologic techniques achieve a great development in studies of soil samples. The objective of this research
is to improve methods for microbial prospecting of oil and gas by applying culture-independent techniques to soil sampled
from above a known oil and gas field. Firstly, the community structure of soil bacteria above the Ban 876 Gas and Oil Field
was analyzed based on 16S rRNA gene clone libraries. The soil bacteria communities were consistently different along the depth;
however, Chloroflexi and Gemmatimonadetes were predominant and methanotrophs were minor in both bacteria libraries (DGS1 and DGS2). Secondly, the numbers of methane-oxidizing
bacteria, quantified using a culture-dependent procedure and culture-independent group-specific real-time PCR (RT-PCR), respectively,
were inconsistent with a quantify variance of one or two orders of magnitude. Special emphasis was given to the counting advantages
of RT-PCR based on the methanotrophic pmoA gene. Finally, the diversity and distribution of methanotrophic communities in the soil samples were analyzed by constructing
clone libraries of functional gene. All 508-bp inserts in clones phylogenetically belonged to the methanotrophic pmoA gene with similarities from 83% to 100%. However, most of the similarities were below 96%. Five clone libraries of methanotrophs
clearly showed that the anomalous methanotrophs (Methylosinus and Methylocystis) occupy the studied area. 相似文献
992.
993.
994.
995.
Mingxing Teng Wentao Wu Zhixiang Li Guangwen Yang Jian Qin Yikai Wang Zhijing Hu Haiheng Dong Lijuan Hou Guoping Hu Liang Shen Yang Zhang Jian Li Shuhui Chen Jingwei Tian Liang Ye Jianzhao Zhang Hongbo Wang 《Bioorganic & medicinal chemistry letters》2017,27(22):4979-4984
hNav1.7 receives a lot of attention owing to its attractive mechanism of action in pain processing pathway. We have previously reported our design of a novel series of tetrahydropyridine analogues towards hNav1.7 selective inhibitors. Herein, we disclose further efforts to the optimization of hit compound (?)-6, which led to the identification of aminocyclohexene analogues (?)-9 and (?)-17 with good potency, high selectivity, and minimal CYP inhibition. Both compounds (?)-9 and (?)-17 demonstrated improved pharmacokinetic profiles in rats, and robust efficacy in rat formalin-induced nociception and spinal nerve ligation (SNL) models. 相似文献
996.
为了降低野生型葡激酶 (wild- type staphylokinase,wt- Sak)的免疫原性 ,对已构建的葡激酶N端缺失突变体 (ΔNSak) c DNA进行改造 ,将其主要的抗原决定簇编码序列突变为丙氨酸密码子 .该突变体 (ΔNMSak) c DNA与原核表达载体 p LY- 4重组后 ,转化大肠杆菌 JF1 1 2 5.经温度诱导 ,ΔNMSak获得高效表达 ,重组蛋白占全菌总蛋白的 60 % ,以包涵体形式存在 .包涵体经洗涤 ,8mol/L尿素溶解 ,稀释复性 ,离子交换色谱一步分离至电泳纯 ,纯度达 95%以上 ,分子量与理论值相符 ,比活性 8.5× 1 0 4 HU/mg.经 ELISA法、发色底物法测定 ,ΔNMSak与 wt- Sak制备的兔抗wt- Sak抗血清的免疫反应性显著降低 ,经抗血清温育后 ,wt- Sak活性下降程度远高于 ΔNMSak.ΔNMSak、wt- Sak分别免疫豚鼠 ,以 ELISA法测定豚鼠血清中相应抗体的效价 ,ΔNMSak组的抗体效价明显低于 wt- Sak组 ,表明 ΔNMSak的免疫原性显著下降 . 相似文献
997.
998.
Accumulation of PINK1 on the outer mitochondrial membrane (OMM) is necessary for PINK‐mediated mitophagy. The proton ionophores, like carbonyl cyanide m‐chlorophenylhydrazone (CCCP) and carbonyl cyanide‐4‐(trifluoromethoxy)phenylhydrazone (FCCP), inhibit PINK1 import into mitochondrial matrix and induce PINK1 OMM accumulation. Here, we show that the CHCHD4/GFER disulfide relay system in the mitochondrial intermembrane space (IMS) is required for PINK1 stabilization when mitochondrial membrane potential is lost. Activation of CHCHD4/GFER system by mitochondrial oxidative stress or inhibition of CHCHD4/GFER system with antioxidants can promote or suppress PINK1 accumulation, respectively. Thus data suggest a pivotal role of CHCHD4/GFER system in PINK1 accumulation. The amyotrophic lateral sclerosis‐related superoxide dismutase 1 mutants dysregulated redox state and CHCHD4/GFER system in the IMS, leading to inhibitions of PINK1 accumulation and mitophagy. Thus, the redox system in the IMS is involved in PINK1 accumulation and damaged mitochondrial clearance, which may play roles in mitochondrial dysfunction‐related neurodegenerative diseases. 相似文献
999.
Dan?Yu Fangfang?Bu Jiaojiao?Hou Yongxiang?Kang Zhongdong?YuEmail author 《World journal of microbiology & biotechnology》2016,32(12):192
A post-fire morel collected from Populus simonii stands in Mt. Qingling was identified as Morchella crassipes Mes-20 by using nuclear ribosomal DNA internal transcribed spacer phylogeny. It was inoculated into sweet corn to observe colonized roots in purified culture and in greenhouse experiments. The elongation and maturation zones of sweet corn were remarkably colonized at the cortex intercellular and intracellular cells, vessel cells, and around the Casparian strip, forming ectendomycorrhiza-like structures. Colonization was also observed in the zone of cell division proximal to the root cap. Greenhouse assays with sweet corn showed that this morel stimulated the development of the root system and significantly increased the dry root biomass. M. crassipes also significantly reduced the incidence of Fusarium verticillioides in the kernels of mature ears when inoculated into young ears before Fusarium inoculation and prevented Fusarium infection in corn ears compared with that of the control in the greenhouse. When grown under axenic conditions, M. crassipes produced the phytohormones abscisic acid, indole-3-acetic acid, and salicylic acid. The benefits to plants elicited by M. crassipes may result from these phytohormones which may improve the drought resistance, biomass growth and resistance to Fusarium. 相似文献
1000.
Terrence Tsz-Tai Yuen Jasper Fuk-Woo Chan Bingpeng Yan Cynthia Cheuk-Ying Shum Yuanchen Liu Huiping Shuai Yuxin Hou Xiner Huang Bingjie Hu Yue Chai Chaemin Yoon Tianrenzheng Zhu Huan Liu Jialu Shi Jinjin Zhang Jian-Piao Cai Anna Jinxia Zhang Jie Zhou Feifei Yin Shuofeng Yuan Bao-Zhong Zhang Hin Chu 《International journal of biological sciences》2022,18(12):4714
The Coronavirus Disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the biggest public health challenge the world has witnessed in the past decades. SARS-CoV-2 undergoes constant mutations and new variants of concerns (VOCs) with altered transmissibility, virulence, and/or susceptibility to vaccines and therapeutics continue to emerge. Detailed analysis of host factors involved in virus replication may help to identify novel treatment targets. In this study, we dissected the metabolome derived from COVID-19 patients to identify key host factors that are required for efficient SARS-CoV-2 replication. Through a series of metabolomic analyses, in vitro, and in vivo investigations, we identified ATP citrate lyase (ACLY) as a novel host factor required for efficient replication of SARS-CoV-2 wild-type and variants, including Omicron. ACLY should be further explored as a novel intervention target for COVID-19. 相似文献