全文获取类型
收费全文 | 229篇 |
免费 | 21篇 |
国内免费 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 14篇 |
2018年 | 15篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 14篇 |
2013年 | 23篇 |
2012年 | 21篇 |
2011年 | 24篇 |
2010年 | 11篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 16篇 |
2006年 | 11篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 1篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有251条查询结果,搜索用时 15 毫秒
1.
Plant and Soil - Seeds are involved in the transmission of microorganisms from one plant generation to the next, acting as initial inoculum for the plant microbiome, therefore provide a key source... 相似文献
2.
Isolation and partial characterization of an unusual human immunodeficiency retrovirus from two persons of west-central African origin. 总被引:12,自引:4,他引:8
下载免费PDF全文
![点击此处可从《Journal of virology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
R De Leys B Vanderborght M Vanden Haesevelde L Heyndrickx A van Geel C Wauters R Bernaerts E Saman P Nijs B Willems et al. 《Journal of virology》1990,64(3):1207-1216
An unusual human retrovirus was isolated from two patients with persistent generalized lymphadenopathy who originate from West-Central Africa and are currently residing in Belgium. Although the virus shared a number of the same biological and morphological properties as human immunodeficiency retrovirus type 1 (HIV-1) and HIV-2, significant antigenic differences could be demonstrated. Several of the viral proteins also differed in molecular weight from the corresponding HIV-1 and HIV-2 proteins. Partial chemical cleavage of the most highly conserved viral proteins resulted in patterns which differed from those of HIV-1 and HIV-2. Furthermore, nucleic acid hybridization experiments were capable of discriminating between the virus types. Sequence analysis of the viral U3 region revealed a unique enhancer organization not found in other immunodeficiency viruses. The data indicated that the new isolate is more closely related to HIV-1 than to HIV-2 but clearly differs in a number of important respects. 相似文献
3.
Cloning, nucleotide sequence, and expression of the Brucella melitensis bp26 gene coding for a protein immunogenic in infected sheep 总被引:1,自引:0,他引:1
Axel Cloeckaert Hanane Salih-Alj Debbarh Nieves Vizcaíno Eric Saman Gérard Dubray Michel S. Zygmunt 《FEMS microbiology letters》1996,140(2-3):139-144
Abstract We have previously identified a Brucella melitensis 28 kDa cytosoluble protein (CP28) which was highly immunogenic in infected sheep and which in addition made possible the serological differentiation between infected and B. melitensis Rev.l vaccinated sheep. Monoclonal antibodies against CP28 were used to screen a B. melitensis 16M genomic library and to clone the corresponding gene. DNA sequencing of the gene encoding CP28 of B. melitensis 16M revealed that it was nearly identical to that of the recently published bp26 gene of Brucella abortus vaccine strain S19 coding for a periplasmic protein. The differences between the B. melitensis 16M gene and that of B. abortus S19 consisted of single nucleotide substitutions, one or two codon deletions, one codon addition, and most importantly a 21-bp deletion. The corresponding region of B. abortus S19 contains two 10-bp direct repeats which could have been involved in the genesis of the deletion. Expression of the B. melitensis 16M bp26 gene in Escherichia coli studied by the use of the monoclonal antibodies showed the same characteristics as reported for the B. abortus S19 bp26 gene, i.e. the presence of a higher molecular mass preprotein and a lower molecular mass band which probably corresponds to the mature protein exported to the periplasm. Immunoblotting performed with sera from either naturally infected or B. melitensis H38 experimentally infected sheep confirmed the importance of the B. melitensis CP28/BP26 protein as diagnostic antigen. 相似文献
4.
Fatemeh Davodabadi Shekoufeh Mirinejad Sonia Fathi-Karkan Mahdi Majidpour Narges Ajalli Roghayeh Sheervalilou Saman Sargazi Dominika Rozmus Abbas Rahdar Ana M. Diez-Pascual 《Biotechnology progress》2023,39(5):e3366
Aptamers (Apts) are synthetic nucleic acid ligands that can be engineered to target various molecules, including amino acids, proteins, and pharmaceuticals. Through a series of adsorption, recovery, and amplification steps, Apts are extracted from combinatorial libraries of synthesized nucleic acids. Using aptasensors in bioanalysis and biomedicine can be improved by combining them with nanomaterials. Moreover, Apt-associated nanomaterials, including liposomes, polymeric, dendrimers, carbon nanomaterials, silica, nanorods, magnetic NPs, and quantum dots (QDs), have been widely used as promising nanotools in biomedicine. Following surface modifications and conjugation with appropriate functional groups, these nanomaterials can be successfully used in aptasensing. Advanced biological assays can use Apts immobilized on QD surfaces through physical interaction and chemical bonding. Accordingly, modern QD aptasensing platforms rely on interactions between QDs, Apts, and targets to detect them. QD-Apt conjugates can be used to directly detect prostate, ovarian, colorectal, and lung cancers or simultaneously detect biomarkers associated with these malignancies. Tenascin-C, mucin 1, prostate-specific antigen, prostate-specific membrane antigen, nucleolin, growth factors, and exosomes are among the cancer biomarkers that can be sensitively detected using such bioconjugates. Furthermore, Apt-conjugated QDs have shown great potential for controlling bacterial infections such as Bacillus thuringiensis, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Campylobacter jejuni, Staphylococcus aureus, and Salmonella typhimurium. This comprehensive review discusses recent advancements in the design of QD-Apt bioconjugates and their applications in cancer and bacterial theranostics. 相似文献
5.
6.
Elevated atmospheric [CO2] can dramatically increase wheat yields in semi‐arid environments and buffer against heat waves
下载免费PDF全文
![点击此处可从《Global Change Biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Glenn J. Fitzgerald Michael Tausz Garry O'Leary Mahabubur R. Mollah Sabine Tausz‐Posch Saman Seneweera Ivan Mock Markus Löw Debra L. Partington David McNeil Robert M. Norton 《Global Change Biology》2016,22(6):2269-2284
Wheat production will be impacted by increasing concentration of atmospheric CO2 [CO2], which is expected to rise from about 400 μmol mol?1 in 2015 to 550 μmol mol?1 by 2050. Changes to plant physiology and crop responses from elevated [CO2] (e[CO2]) are well documented for some environments, but field‐level responses in dryland Mediterranean environments with terminal drought and heat waves are scarce. The Australian Grains Free Air CO2 Enrichment facility was established to compare wheat (Triticum aestivum) growth and yield under ambient (~370 μmol?1 in 2007) and e[CO2] (550 μmol?1) in semi‐arid environments. Experiments were undertaken at two dryland sites (Horsham and Walpeup) across three years with two cultivars, two sowing times and two irrigation treatments. Mean yield stimulation due to e[CO2] was 24% at Horsham and 53% at Walpeup, with some treatment responses greater than 70%, depending on environment. Under supplemental irrigation, e[CO2] stimulated yields at Horsham by 37% compared to 13% under rainfed conditions, showing that water limited growth and yield response to e[CO2]. Heat wave effects were ameliorated under e[CO2] as shown by reductions of 31% and 54% in screenings and 10% and 12% larger kernels (Horsham and Walpeup). Greatest yield stimulations occurred in the e[CO2] late sowing and heat stressed treatments, when supplied with more water. There were no clear differences in cultivar response due to e[CO2]. Multiple regression showed that yield response to e[CO2] depended on temperatures and water availability before and after anthesis. Thus, timing of temperature and water and the crop's ability to translocate carbohydrates to the grain postanthesis were all important in determining the e[CO2] response. The large responses to e[CO2] under dryland conditions have not been previously reported and underscore the need for field level research to provide mechanistic understanding for adapting crops to a changing climate. 相似文献
7.
Paul C. D. Newton Mark Lieffering W. M. Saman D. Bowatte Shona C. Brock Chris L. Hunt Phil W. Theobald Des J. Ross 《Plant and Soil》2010,336(1-2):433-441
A decline in the availability of nitrogen (N) for plant growth (progressive nitrogen limitation or PNL) is a feedback that could constrain terrestrial ecosystem responses to elevated atmospheric CO2. Several long-term CO2 enrichment experiments have measured changes in plant and soil pools and fluxes consistent with PNL but evidence for PNL in grasslands is limited. In an 11 year Free Air CO2 Enrichment (FACE) experiment on grazed grassland we found the amount of N harvested in aboveground plant biomass was greater at elevated CO2 but declined over time to be indistinguishable from ambient after 5 years. Re-wetting after a major drought resulted in a large input of N from mineralisation and a return to a higher N harvested under elevated CO2 followed by a further decline. Over these two periods the amount of N in soil significantly increased at elevated CO2. Data from mesocosms introduced into the rings at intervals, and therefore having different lengths of exposure to CO2, showed plant N availability declined at elevated CO2 reaching a new equilibrium after 6 years of exposure. We conclude that the availability of N for plants in this grassland is dynamic but the underlying trend at elevated CO2 is for PNL. 相似文献
8.
Yaghoubi Atieh Khazaei Majid Ghazvini Kiarash Movaqar Aref Avan Amir Hasanian Seyed Mahdi Soleimanpour Saman 《International journal of peptide research and therapeutics》2021,27(2):1057-1067
International Journal of Peptide Research and Therapeutics - Whereas the traditional approaches of cancer therapy including radiotherapy, chemotherapy, and immunotherapy have failed to properly... 相似文献
9.
Plasma Physics Reports - The evaluation of the Coulomb logarithm (CL) for different coupled plasma regimes is examined using generalized CL, effective CL, and conventional CL models. To find out... 相似文献
10.
Mitra Kheirabadi Zohreh Sharafian Hossein Naderi-Manesh Udo Heineman Ulrich Gohlke Saman Hosseinkhani 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(12):2729-2735
Firefly bioluminescence reaction in the presence of Mg2 +, ATP and molecular oxygen is carried out by luciferase. The luciferase structure alterations or modifications of assay conditions determine the bioluminescence color of firefly luciferase. Among different beetle luciferases, Phrixothrix hirtus railroad worm emits either yellow or red bioluminescence color. Sequence alignment analysis shows that the red-emitter luciferase from Phrixothrix hirtus has an additional arginine residue at 353 that is absent in other firefly luciferases. It was reported that insertion of Arg in an important flexible loop350–359 showed changes in bioluminescence color from green to red and the optimum temperature activity was also increased. To explain the color tuning mechanism of firefly luciferase, the structure of native and a mutant (E354R/356R/H431Y) of Lampyris turkestanicus luciferase is determined at 2.7 Å and 2.2 Å resolutions, respectively. The comparison of structure of both types of Lampyris turkestanicus luciferases reveals that the conformation of this flexible loop is significantly changed by addition of two Arg in this region. Moreover, its surface accessibility is affected considerably and some ionic bonds are made by addition of two positive charge residues. Furthermore, we noticed that the hydrogen bonding pattern of His431 with the flexible loop is changed by replacing this residue with Tyr at this position. Juxtaposition of a flexible loop (residues 351–359) in firefly luciferase and corresponding ionic and hydrogen bonds are essential for color emission. 相似文献