全文获取类型
收费全文 | 1252篇 |
免费 | 58篇 |
国内免费 | 5篇 |
出版年
2024年 | 3篇 |
2023年 | 23篇 |
2022年 | 46篇 |
2021年 | 104篇 |
2020年 | 48篇 |
2019年 | 48篇 |
2018年 | 73篇 |
2017年 | 49篇 |
2016年 | 59篇 |
2015年 | 79篇 |
2014年 | 81篇 |
2013年 | 90篇 |
2012年 | 100篇 |
2011年 | 90篇 |
2010年 | 44篇 |
2009年 | 46篇 |
2008年 | 43篇 |
2007年 | 41篇 |
2006年 | 22篇 |
2005年 | 35篇 |
2004年 | 29篇 |
2003年 | 27篇 |
2002年 | 19篇 |
2001年 | 2篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 8篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1965年 | 2篇 |
1964年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有1315条查询结果,搜索用时 15 毫秒
931.
RPA activates the XPF‐ERCC1 endonuclease to initiate processing of DNA interstrand crosslinks
下载免费PDF全文
![点击此处可从《The EMBO journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ummi B Abdullah Joanna F McGouran Sanja Brolih Denis Ptchelkine Afaf H El‐Sagheer Tom Brown Peter J McHugh 《The EMBO journal》2017,36(14):2047-2060
During replication‐coupled DNA interstrand crosslink (ICL) repair, the XPF‐ERCC1 endonuclease is required for the incisions that release, or “unhook”, ICLs, but the mechanism of ICL unhooking remains largely unknown. Incisions are triggered when the nascent leading strand of a replication fork strikes the ICL. Here, we report that while purified XPF‐ERCC1 incises simple ICL‐containing model replication fork structures, the presence of a nascent leading strand, modelling the effects of replication arrest, inhibits this activity. Strikingly, the addition of the single‐stranded DNA (ssDNA)‐binding replication protein A (RPA) selectively restores XPF‐ERCC1 endonuclease activity on this structure. The 5′–3′ exonuclease SNM1A can load from the XPF‐ERCC1‐RPA‐induced incisions and digest past the crosslink to quantitatively complete the unhooking reaction. We postulate that these collaborative activities of XPF‐ERCC1, RPA and SNM1A might explain how ICL unhooking is achieved in vivo. 相似文献
932.
Abdullah Salci 《Journal of biomolecular structure & dynamics》2017,35(1):8-16
The interaction of Pyronin Y with human serum albumin (HSA) has been investigated systematically by fluorescence, absorption, fluorescence decay lifetime measurements, FTIR, synchronous fluorescence spectroscopy, and molecular modeling method. The spectroscopic and fluorescence quenching experiments show that Pyronin Y may show a static quenching mechanism with HSA. The specific binding distance of 1.96 nm between HSA and Pyronin Y was obtained via Förster non-radiation energy transfer method. The thermodynamic parameters indicate that the electrostatic interactions play a significant role during the binding process. In addition, synchronous fluorescence and FT-IR spectra indicated that the conformation and microenvironment of HSA were not influenced with the addition of Pyronin Y. The obtained results can be of biological significance in photodynamic therapy. 相似文献
933.
934.
Sleep and Biological Rhythms - This study aims to assess the latent dimensional structure of sleep quality as measured by seven components of the Pittsburgh Sleep Quality Index (PSQI) and evaluate... 相似文献
935.
Variation in Phenolic Profile, β‐Carotene and Flavonoid Contents,Biological Activities of Two Tagetes Species from Pakistani Flora
下载免费PDF全文
![点击此处可从《化学与生物多样性》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Muhammad Adnan Ayub Abdullah Ijaz Hussain Muhammad Asif Hanif Shahzad Ali Shahid Chatha Ghulam Mustafa Kamal Muhammad Shahid Omar Janneh 《化学与生物多样性》2017,14(6)
The objective of present study was to evaluate the variation in phenolic profile, β‐carotene, flavonoid contents, antioxidant and antimicrobial properties of Tagetes erecta and Tagetes patula (T. erecta and T. patula) through different in vitro assays. Antioxidant activity was determined through 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical scavenging and inhibition of linoleic acid peroxidation assays and antibacterial and antifungal activities studied using the disc diffusion and resazurin microtiter‐plate assays against bacterial and fungal strains. Moreover, total phenolics (TP), total carotenoids (TC) and total flavonoids (TF) were also determined. Highest (TP 35.8 mg GAE/g) and TF (16.9 mg CE/g) contents were found in MeOH extract of T. patula. T. erecta extract showed higher TC contents (6.45 mg/g) than T. patula extract (6.32 mg/g). T. erecta exhibited the highest DPPH radical‐scavenging activity (IC50) (5.73 μg/mL) and inhibition of linoleic acid peroxidation (80.1%). RP‐HPLC revealed the presence of caffeic acid, sinapic acid and ferulic acid in Tagetes extracts, m‐coumaric acid in T. erecta whereas chlorogenic acid in T. patula extract only. Both extracts possessed promising antimicrobial activity compared to the ciprofloxacin and flumequine (+ve controls) against Bacillus subtilis and Alternaria alternate. Both extract were rich source of polyphenols exhibiting excellent biological activities. 相似文献
936.
Identification of Mungbean yellow mosaic Indian virus Associated with Tomato Leaf Curl Betasatellite Infecting Phaseolus vulgaris in Oman
下载免费PDF全文
![点击此处可从《Journal of Phytopathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Muhammad S. Shahid Rob W. Briddon Abdullah M. Al‐Sadi 《Journal of Phytopathology》2017,165(3):204-211
Kidney bean (Phaseolus vulgaris) plants exhibiting foliar yellow mosaic symptoms and some leaf crumpling were identified in the Al Batinah region of Oman. Rolling circle amplification and polymerase chain reaction identified a bipartite begomovirus (family Geminiviridae) and a betasatellite in association with the symptomatic plants. Analysis of full‐length sequences showed the virus to be Mungbean yellow mosaic Indian virus (MYMIV) and the betasatellite Tomato leaf curl betasatellite (ToLCB). This is the first identification of a legume‐adapted begomovirus in Oman and the first identification of MYMIV in association with the betasatellite ToLCB. The isolate of MYMIV from Oman shows the greatest levels of sequence identity to isolates occurring in South Asia and South‐East Asia, suggesting that the virus has only recently been introduced. The significance of these findings is discussed. 相似文献
937.
Non-coding RNAs (ncRNAs) are critical regulators of gene expression in essentially all life forms. Long ncRNAs (lncRNAs) and microRNAs (miRNAs) are two important RNA classes possessing regulatory functions. Up to date, many primate-specific ncRNAs have been identified and investigated. Their expression specificity to primate lineage suggests primate-specific roles. It is thus critical to elucidate the biological significance of primate or even human-specific ncRNAs, and to develop potential ncRNA-based therapeutics. Here, we have summarized the studies regarding regulatory roles of some key primate-specific lncRNAs and miRNAs. 相似文献
938.
Nizar Jamal Haddad Adjlane Noureddine Banan Al‐Shagour Wahida Loucif‐Ayad Mogbel A. A. El‐Niweiri Eman Anaswah Wafaa Abu Hammour Dany El‐Obeid Albaba Imad Mohamed A. Shebl Abdulhusien Sehen Almaleky Abdullah Nasher Nagara Walid Mohamed Fouad Bergigui Orlando Yañez Joachim R. de Miranda 《Insect Science》2017,24(1):103-113
Three hundred and eleven honeybee samples from 12 countries in the Middle East and North Africa (MENA) (Jordan, Lebanon, Syria, Iraq, Egypt, Libya, Tunisia, Algeria, Morocco, Yemen, Palestine, and Sudan) were analyzed for the presence of deformed wing virus (DWV). The prevalence of DWV throughout the MENA region was pervasive, but variable. The highest prevalence was found in Lebanon and Syria, with prevalence dropping in Palestine, Jordan, and Egypt before increasing slightly moving westwards to Algeria and Morocco Phylogenetic analysis of a 194 nucleotide section of the DWV Lp gene did not identify any significant phylogenetic resolution among the samples, although the sequences did show consistent regional clustering, including an interesting geographic gradient from Morocco through North Africa to Jordan and Syria. The sequences revealed several clear variability hotspots in the deduced amino acid sequence, which furthermore showed some patterns of regional identity. Furthermore, the sequence variants from the Middle East and North Africa appear more numerous and diverse than those from Europe. 相似文献
939.
Toshihiro Yamada Toshinori Okuda Makmom Abdullah Muhamad Awang Akio Furukawa 《Oecologia》2000,125(4):476-482
On a monoaxial erect stem of trees with continuous leafing, the older leaves would be quickly shaded by newer (upper) leaves if the trees did not have any compensating mechanisms to avoid self-shading. We hypothesized that the dynamic adjustment of leaf deployment, by regulating the patterns of leaf growth and by changing leaf orientation as leaves age, is a compensating mechanism. To verify this hypothesis, we analyzed leaf development and crown structure of a Far Eastern tropical pioneer tree species, Macaranga gigantea (Rub. f. et Toll.) M.A., which unfolds huge leaves directly on a monoaxial stem with a short leafing interval. Petioles required more than 90 days for full elongation and the petiole angle (the angle between the petiole axis and the vertical) increased over time. Thus, a series of leaves on a stem progressively increased in petiole length and petiole angle from the youngest to the oldest leaves. This is beneficial because it decreases the degree of self-shading within a crown. A simulation suggested that an average crown for the M. gigantea seedlings, which was constructed using empirically determined morphometric data cannot entirely eliminate self-shading within the crown. But an average crown had a lower degree of self-shading, with less dry mass allocation to the petiole than simulated crowns that were identical to the average crown in all but one respect: they had constant petiole lengths or petiole angles. We conclude that M. gigantea seedlings reduce self-shading by regulating elongation of the petiole and changes in the petiole angle with increasing leaf age. 相似文献
940.