全文获取类型
收费全文 | 510篇 |
免费 | 24篇 |
国内免费 | 4篇 |
出版年
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 29篇 |
2020年 | 18篇 |
2019年 | 17篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 20篇 |
2015年 | 29篇 |
2014年 | 27篇 |
2013年 | 35篇 |
2012年 | 31篇 |
2011年 | 45篇 |
2010年 | 18篇 |
2009年 | 18篇 |
2008年 | 26篇 |
2007年 | 28篇 |
2006年 | 24篇 |
2005年 | 26篇 |
2004年 | 13篇 |
2003年 | 15篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 6篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有538条查询结果,搜索用时 31 毫秒
81.
Suppression of CCR5- but not CXCR4-tropic HIV-1 in lymphoid tissue by human herpesvirus 6. 总被引:11,自引:0,他引:11
J C Grivel Y Ito G Fagà F Santoro F Shaheen M S Malnati W Fitzgerald P Lusso L Margolis 《Nature medicine》2001,7(11):1232-1235
HIV-1 infects target cells via a receptor complex formed by CD4 and a chemokine receptor, primarily CCR5 or CXCR4 (ref. 1). Commonly, HIV-1 transmission is mediated by CCR5-tropic variants, also designated slow/low, non-syncytia-inducer or macrophage-tropic, which dominate the early stages of HIV-1 infection and frequently persist during the entire course of the disease. In contrast, HIV-1 variants that use CXCR4 are typically detected at the later stages, and are associated with a rapid decline in CD4+ T cells and progression to AIDS (refs. 2,7-11). Disease progression is also associated with the emergence of concurrent infections that may affect the course of HIV disease by unknown mechanisms. A lymphotropic agent frequently reactivated in HIV-infected patients is human herpesvirus 6 (HHV-6), which has been proposed as a cofactor in AIDS progression. Here we show that in human lymphoid tissue ex vivo, HHV-6 affects HIV-1 infection in a coreceptor-dependent manner, suppressing CCR5-tropic but not CXCR4-tropic HIV-1 replication, as shown with both uncloned viral isolates and isogenic molecular chimeras. Furthermore, we demonstrate that HHV-6 increases the production of the CCR5 ligand RANTES ('regulated upon activation, normal T-cell expressed and secreted'), the most potent HIV-inhibitory CC chemokine, and that exogenous RANTES mimics the effects of HHV-6 on HIV-1, providing a mechanism for the selective blockade of CCR5-tropic HIV-1. Our data suggest that HHV-6 may profoundly influence the course of HIV-1 infection. 相似文献
82.
Hassina Tabassum Chenxu Zhi Tanveer Hussain Tianjie Qiu Waseem Aftab Ruqiang Zou 《Liver Transplantation》2019,9(39)
Trogtalite CoSe2 nanobuds encapsulated into boron and nitrogen codoped graphene (BCN) nanotubes (CoSe2@BCN‐750) are synthesized via a concurrent thermal decomposition and selenization processes. The CoSe2@BCN‐750 nanotubes deliver an excellent storage capacity of 580 mA h g?1 at current density of 100 mA g?1 at 100th cycle, as the anode of a sodium ion battery. The CoSe2@BCN‐750 nanotubes exhibit a significant rate capability (100–2000 mA g?1 current density) and high stability (almost 98% storage retention after 4000 cycles at large current density of 8000 mA g?1). The reasons for these excellent storage properties are illuminated by theoretical calculations of the relevant models, and various possible Na+ ion storage sites are identified through first‐principles calculations. These results demonstrate that the insertion of heteroatoms, B–C, N–C as well as CoSe2, into BCN tubes, enables the observed excellent adsorption energy of Na+ ions in high energy storage devices, which supports the experimental results. 相似文献
83.
Gurpreet Singh-Ranger Noleen Rajarajan Syed Aftab David Stoker 《International Seminars in Surgical Oncology : ISSO》2007,4(1):27
Isolated splenic peliosis is an extremely rare occurrence, and this disease often manifests itself with spontaneous haemoperitoneum.We report a case where an otherwise healthy patient was found to have splenomegaly on clinical examination. On computerised tomography, a diagnosis of splenic malignancy was made, and the patient underwent a splenectomy. Histological examination gave the diagnosis of splenic peliosis, which had not been considered prior to the operation. In retrospect, splenectomy was the most prudent course of action, as the risk of spontaneous haemorrhage and fatality was eliminated. This case emphasises the need to retain an index of suspicion for this condition, even in otherwise healthy patients, and is a reminder of the usefulness of total splenectomy in the current era of minimally invasive diagnostic techniques. 相似文献
84.
Shaheen E Lakhan 《Molecular neurodegeneration》2007,2(1):1-3
John Finberg is a professor of pharmacology at the Faculty of Medicine, Technion – Israel Institute of Technology, home of Israel's two Nobel laureates. He and his colleague Prof. Moussa Youdim were instrumental in the early clinical development of the anti-Parkinson drug rasagiline, which gained UK- and EU-marketing authorization in 2005 and US FDA approval in 2006. In our interview, Finberg reflects on his clinical research to develop rasagiline as a commercial drug and its proposed pharmacological mechanisms of action. Moreover, he elucidates the current state of anti-Parkinson drug discovery and offers direction for future research. 相似文献
85.
The mycoflora of the hair in 178 goats from the West Bank of Jordan was analysed and the frequency of occurrence and the relative importance value for the different keratinophilic fungi found were calculated. One hundred and seven species which belong to 38 genera were isolated. Thirty six of these species were either well recognised agents of mycoses (Trichophyton mentagrophytes, T. verrucosum, and M. nanum), or have been frequently isolated from human and animal lesions (Arthroderma spp., Acremonium kiliense, Alternaria alternata, Aspergillus flavus, Cladosporium carionii, and several other species). These potentially pathogenic fungal species comprised 66.9% of all keratinophilic fungi found on the hair of goats. The role of this animal as a reservoir for dermatophytes and other potentially pathogenic fungi is discussed. 相似文献
86.
Perveen Sumera Khan Tehmina Ahsan Shaheen Humaira Naz Rabia Hyder Muhammad Zeeshan Ijaz Bushra Naqvi S. M. Saqlan Yasmin Tayyaba 《In vitro cellular & developmental biology. Plant》2021,57(6):907-922
In Vitro Cellular & Developmental Biology - Plant - The OsRGLP1 gene was overexpressed under the control of CaMV 35S promoter in tomato (Solanum lycopersicum L.) plants using... 相似文献
87.
Julian R. Dupuis Sheina B. Sim Michael San Jose Luc Leblanc M. Aftab Hoassain Daniel Rubinoff Scott M. Geib 《Biological invasions》2018,20(5):1211-1228
Population genetics is a powerful tool for invasion biology and pest management, and useful for a range of questions from tracing invasion pathways to informing management decisions with inference of population demographics. Genomics greatly increases the resolution of population-scale analyses, yet outside of model species with extensive genomic resources, few studies have used population genomics in invasion biology. We use genome-wide single nucleotide polymorphisms (SNPs) to investigate population genomic structure with samples from across the range of melon fly, Bactrocera cucurbitae (Coquillett, 1849), a highly polyphagous pest of commercial produce. We then make use of a chromosome-scale genome assembly and gene set to compare signatures of selection across the melon fly’s genome, both across our sampling as a whole and in the context of two independent, established introductions. Using multiple approaches, we find support for six genetic clusters across melon fly’s distribution. Some of these agree with previously identified genetic clusters using microsatellites, but consensus of clusters in mainland and oceanic southeast Asia is confounded by variable sampling between studies. We find few adaptive signatures across the genome, and virtually no unique signatures when comparing the two independent introductions, which suggests that similar management strategies are appropriate across melon fly’s range. This is the first use of genome-wide data to characterize population structure in tephritid fruit fly pests, and our SNP dataset provides a foundation for objective and cost-effective genotyping of previously collected melon fly specimens. Future research needs to focus on truly comprehensive sampling across melon fly’s range to overcome the historic variability of range-wide estimates of population structure for this pest. 相似文献
88.
Alaa Shaheen 《Cell stress & chaperones》2018,23(5):797-806
The unfolded protein response (UPR) is an adaptive cellular response that aims to relieve endoplasmic reticulum (ER) stress via several mechanisms, including inhibition of protein synthesis and enhancement of protein folding and degradation. There is a controversy over the effect of the UPR on ER protein export. While some investigators suggested that ER export is inhibited during ER stress, others suggested the opposite. In this article, their conflicting studies are analyzed and compared in attempt to solve this controversy. The UPR appears indeed to enhance ER export, possibly via multiple mechanisms. However, another factor, which is the integrity of the folding machinery/environment inside ER, determines whether ER export will appear increased or decreased during experimentation. Also, different methods of stress induction appear to have different effects on ER export. Thus, improvement of ER export may represent a new mechanism by which the UPR alleviates ER stress. This may help researchers to understand how the UPR works inside cells and how to manipulate it to alter cell fate during stress, either to promote cell survival or death. This may open up new approaches for the treatment of ER stress-related diseases. 相似文献
89.
Jayanta Kumar Biswas Anurupa Banerjee Mahendra Kumar Rai Jörg Rinklebe Sabry M. Shaheen Santosh Kumar Sarkar Madhab Chandra Dash Anilava Kaviraj Uwe Langer Hocheol Song Meththika Vithanage Monojit Mondal Nabeel Khan Niazi 《Biodegradation》2018,29(4):323-337
The aim was to isolate, characterize, and explore potentials of gut bacteria from the earthworm (Metaphire posthuma) and imply these bacteria for remediation of Cu(II) and Zn(II). An extracellular polymeric substance (EPS) producing gut bacteria (Bacillus licheniformis strain KX657843) was isolated and identified based on 16S rRNA sequencing and phylogenetic analysis. The strain showed maximum tolerance of 8 and 6 mM for Cu(II) and Zn(II) respectively. It removed 34.5% of Cu(II) and 54.4% of Zn(II) at 25 mg L?1 after 72 and 96 h incubation respectively. The bacteria possessed a great potential to produce indole acetic acid (38.49 μg mL?1) at 5 mg mL?1 l-tryptophan following 12 days incubation. The sterilized seeds of mung beans (Vigna radiata) displayed greater germination and growth under bacterium enriched condition. We observed that the bacterial strain phosphate solubilization ability with a maximum of 204.2 mg L?1 in absence of Cu(II) and Zn(II). Endowed with biosurfactant property the bacterium exhibited 24% emulsification index. The bacterium offered significant potential of plant growth promotion, Cu(II) and Zn(II) removal, and as such this study is the first report on EPS producing B. licheniformis KX657843 from earthworm which can be applied as powerful tool in remediation programs of Cu(II) and Zn(II) contaminated sites. 相似文献
90.
Anas M. Alazami Sarah M. Al-Qattan Eissa Faqeih Amal Alhashem Muneera Alshammari Fatema Alzahrani Mohammed S. Al-Dosari Nisha Patel Afaf Alsagheir Bassam Binabbas Hamad Alzaidan Abdulmonem Alsiddiky Nasser Alharbi Majid Alfadhel Amal Kentab Riza M. Daza Martin Kircher Jay Shendure Mais Hashem Saif Alshahrani Zuhair Rahbeeni Ola Khalifa Ranad Shaheen Fowzan S. Alkuraya 《Human genetics》2016,135(5):525-540