全文获取类型
收费全文 | 553篇 |
免费 | 36篇 |
国内免费 | 1篇 |
出版年
2023年 | 11篇 |
2022年 | 9篇 |
2021年 | 27篇 |
2020年 | 18篇 |
2019年 | 29篇 |
2018年 | 25篇 |
2017年 | 22篇 |
2016年 | 23篇 |
2015年 | 45篇 |
2014年 | 48篇 |
2013年 | 41篇 |
2012年 | 35篇 |
2011年 | 37篇 |
2010年 | 16篇 |
2009年 | 11篇 |
2008年 | 15篇 |
2007年 | 17篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1986年 | 4篇 |
1985年 | 11篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有590条查询结果,搜索用时 15 毫秒
21.
Akram Nudrat Aisha Shafiq Fahad Ashraf Muhammad Iqbal Muhammad Ahmad Parvaiz 《Journal of Plant Growth Regulation》2021,40(3):891-905
Journal of Plant Growth Regulation - Plant biofibers are of great economic and commercial importance. Among various fiber producing crops, cotton (Gossypium hirsutum L.), hemp (Cannabis sativa L.),... 相似文献
22.
23.
Saghir Abbas Muhammad Tariq Javed Qasim Ali Muhammad Sohail Akram Kashif Tanwir Shafaqat Ali Hassan Javed Chaudhary Naeem Iqbal 《Physiology and Molecular Biology of Plants》2021,27(2):297
Cadmium (Cd) in soil–plant system can abridge plant growth by initiating alterations in root zones. Hydroponics and rhizoboxes are useful techniques to monitor plant responses against various natural and/or induced metal stresses. However, soil based studies are considered more appropriate in order to devise efficient food safety and remediation strategies. The present research evaluated the Cd-mediated variations in elemental dynamics of rhizospheric soil together with in planta ionomics and morpho-physio-biochemical traits of two differentially Cd responsive maize cultivars. Cd-sensitive (31P41) and Cd-tolerant (3062) cultivars were grown in pots filled with 0, 20, 40, 60 and 80 µg/kg CdCl2 supplemented soil. The results depicted that the maize cultivars significantly influenced the elemental dynamics of rhizosphere as well as in planta mineral accumulation under applied Cd stress. The uptake and translocation of N, P, K, Ca, Mg, Zn and Fe from rhizosphere and root cell sap was significantly higher in Cd stressed cv. 3062 as compared to cv. 31P41. In sensitive cultivar (31P41), Cd toxicity resulted in significantly prominent reduction of biomass, leaf area, chlorophyll, carotenoids, protein contents as well as catalase activity in comparison to tolerant one (3062). Analysis of tolerance indexes (TIs) validated that cv. 3062 exhibited advantageous growth and efficient Cd tolerance due to elevated proline, phenolics and activity of antioxidative machinery as compared to cv. 31P41. The cv. 3062 exhibited 54% and 37% less Cd bio-concentration (BCF) and translocation factors (TF), respectively in comparison to cv. 31P41 under highest Cd stress regime. Lower BCF and TF designated a higher Cd stabilization by tolerant cultivar (3062) in rhizospheric zone and its potential use in future remediation plans. 相似文献
24.
Patrone Vania Al-Surrayai Tahani Romaniello Francesco Fontana Alessandra Milani Giovanni Sagheddu Valeria Puglisi Edoardo Callegari Maria Luisa Al-Mansour Hamad Kishk Mohamed Waheed Morelli Lorenzo 《Probiotics and antimicrobial proteins》2021,13(3):809-823
Probiotics and Antimicrobial Proteins - Probiotics represent a possible strategy for controlling intestinal infections in livestock. Members of the Weissella genus are increasingly being studied... 相似文献
25.
Muhammad Arslan Khan Hasan Riaz Muhammad Raheel Qaiser Shakeel Ummara Waheed Nadeem Ahmed Muhammad Bashair Waqas Ashraf Hafiz Tassawar Abbas Maria Siddique Maria Khan Ambreen Naz Musarrat Shaheen Asif Mahmood Arif Habib Ali Muhammad Nasir Mohammad Javed Ansari Hamed A. Ghramh Khalid Ali Khan 《Saudi Journal of Biological Sciences》2021,28(1):1-9
Root-knot nematodes Meloidogyne incognita (Kofoid and White) Chitwood and Rhizoctonia bataticola (Taub.) Butler, fungus, are very dangerous root damaging pathogens. Present study was planned to establish a chemical control of these root deteriorating pathogens under lab conditions as well as in field. Maximum death rate of nematode juveniles and minimum numbers of nematode eggs hatched were recorded in plates treated with Cadusafos (Rugby® 100G) @12 g/100 ml and Cartap® (4% G) @9g/100 ml. Chemical treatment of Rhizoctonia bataticola with Trifloxystrobin + Tebuconazole (Nativo®) @0.2 g/100 ml and Mancozeb + Matalaxyl (Axiom) @0.25 g/100 ml significantly controlled the mycelial growth in plates. The best treatments tested in laboratory were applied in field as protective and curative treatments. Results proved that chemical control of root-knot nematode and root rot fungi by tested chemicals at recommended time and dose is a significant management technique under field conditions. 相似文献
26.
YanPing Wang EJiao Wu Yahuza Lurwanu JiPeng Ding DunChun He Abdul Waheed Oswald Nkurikiyimfura ShiTing Liu WenYang Li ZongHua Wang Lina Yang Jiasui Zhan 《Ecology and evolution》2021,11(10):5484
Genetic variation plays a fundamental role in pathogen''s adaptation to environmental stresses. Pathogens with low genetic variation tend to survive and proliferate more poorly due to their lack of genotypic/phenotypic polymorphisms in responding to fluctuating environments. Evolutionary theory hypothesizes that the adaptive disadvantage of genes with low genomic variation can be compensated for structural diversity of proteins through post‐translation modification (PTM) but this theory is rarely tested experimentally and its implication to sustainable disease management is hardly discussed. In this study, we analyzed nucleotide characteristics of eukaryotic translation elongation factor‐1α (eEF‐lα) gene from 165 Phytophthora infestans isolates and the physical and chemical properties of its derived proteins. We found a low sequence variation of eEF‐lα protein, possibly attributable to purifying selection and a lack of intra‐genic recombination rather than reduced mutation. In the only two isoforms detected by the study, the major one accounted for >95% of the pathogen collection and displayed a significantly higher fitness than the minor one. High lysine representation enhances the opportunity of the eEF‐1α protein to be methylated and the absence of disulfide bonds is consistent with the structural prediction showing that many disordered regions are existed in the protein. Methylation, structural disordering, and possibly other PTMs ensure the ability of the protein to modify its functions during biological, cellular and biochemical processes, and compensate for its adaptive disadvantage caused by sequence conservation. Our results indicate that PTMs may function synergistically with nucleotide codes to regulate the adaptive landscape of eEF‐1α, possibly as well as other housekeeping genes, in P. infestans. Compensatory evolution between pre‐ and post‐translational phase in eEF‐1α could enable pathogens quickly adapting to disease management strategies while efficiently maintaining critical roles of the protein playing in biological, cellular, and biochemical activities. Implications of these results to sustainable plant disease management are discussed. 相似文献
27.
In electromagnetic dosimetry, anatomical human models are commonly obtained by segmentation of magnetic resonance imaging or computed tomography scans. In this paper, a human head model extracted from thermal infrared images is examined in terms of its applicability to specific absorption rate (SAR) calculations. Since thermal scans are two-dimensional (2D) representation of surface temperature, this allows researchers to overcome the extensive computational demand associated with 3D simulation. The numerical calculations are performed using the finite-difference time-domain method with mesh sizes of 2 mm at 900 MHz plane wave irradiation. The power density of the incident plane wave is assumed to be 10 W/m2. Computations were compared with a realistic anatomical head model. The results show that although there were marked differences in the local SAR distribution in the various tissues in the two models, the 1 g peak SAR values are approximately similar in the two models. 相似文献
28.
29.
Leonardo P. Farias Greice Krautz-Peterson Cibele A. Tararam Bogar O. Araujo-Montoya Tatiana R. Fraga Henrique K. Rofatto Floriano P. Silva-Jr Lourdes Isaac Akram A. Da'dara R. Alan Wilson Charles B. Shoemaker Luciana C. C. Leite 《PLoS neglected tropical diseases》2013,7(10)
Background
It is believed that schistosomes evade complement-mediated killing by expressing regulatory proteins on their surface. Recently, six homologues of human CD59, an important inhibitor of the complement system membrane attack complex, were identified in the schistosome genome. Therefore, it is important to investigate whether these molecules could act as CD59-like complement inhibitors in schistosomes as part of an immune evasion strategy.Methodology/Principal Findings
Herein, we describe the molecular characterization of seven putative SmCD59-like genes and attempt to address the putative biological function of two isoforms. Superimposition analysis of the 3D structure of hCD59 and schistosome sequences revealed that they contain the three-fingered protein domain (TFPD). However, the conserved amino acid residues involved in complement recognition in mammals could not be identified. Real-time RT-PCR and Western blot analysis determined that most of these genes are up-regulated in the transition from free-living cercaria to adult worm stage. Immunolocalization experiments and tegument preparations confirm that at least some of the SmCD59-like proteins are surface-localized; however, significant expression was also detected in internal tissues of adult worms. Finally, the involvement of two SmCD59 proteins in complement inhibition was evaluated by three different approaches: (i) a hemolytic assay using recombinant soluble forms expressed in Pichia pastoris and E. coli; (ii) complement-resistance of CHO cells expressing the respective membrane-anchored proteins; and (iii) the complement killing of schistosomula after gene suppression by RNAi. Our data indicated that these proteins are not involved in the regulation of complement activation.Conclusions
Our results suggest that this group of proteins belongs to the TFPD superfamily. Their expression is associated to intra-host stages, present in the tegument surface, and also in intra-parasite tissues. Three distinct approaches using SmCD59 proteins to inhibit complement strongly suggested that these proteins are not complement inhibitors and their function in schistosomes remains to be determined. 相似文献30.
Razieh P. Ahwazi Melika Kiani Meshkat Dinarvand Akram Assali Farnaz S. M. Tekie Rasoul Dinarvand Fatemeh Atyabi 《Journal of cellular physiology》2020,235(3):2049-2059
RNA interference is one of the prosperous approaches for cancer treatment. However, small interfering RNA (siRNA) delivery to cancer cells has been faced with various challenges restricting their clinical application over the decades. Since ROR1 is an onco-embryonic gene overexpressed in many malignancies, suppression of ROR1 by siRNA can potentially fight cancer. Herein, a delivery system for ROR1 siRNA based on HIV-1 TAT peptide-capped gold nanoparticles (GNPs) was developed to treat breast cancer. Besides, we introduced a new feasible method for conjugating the peptide to the nanoparticles. Since the GNPs have high affinity to the sulfur, the findings demonstrated the peptide successfully conjugated to the nanoparticles via Au–S bonds. As positively charged nanoparticles showed high cellular uptake, we could use a low concentration of nanoparticles led to high efficient gene transfection with negligible cytotoxicity that was confirmed by flow cytometry, confocal microscopy, gel retardation, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Following transfection, downregulation of ROR1 and its targeted gene, CCND1, induced apoptosis in cancer cells. In conclusion, the reported capped GNPs could be potentially utilized for delivering negatively charged therapeutic agents in particular genes. 相似文献