全文获取类型
收费全文 | 2373篇 |
免费 | 154篇 |
出版年
2022年 | 16篇 |
2021年 | 34篇 |
2020年 | 13篇 |
2019年 | 24篇 |
2018年 | 31篇 |
2017年 | 23篇 |
2016年 | 51篇 |
2015年 | 85篇 |
2014年 | 80篇 |
2013年 | 152篇 |
2012年 | 128篇 |
2011年 | 130篇 |
2010年 | 72篇 |
2009年 | 66篇 |
2008年 | 129篇 |
2007年 | 130篇 |
2006年 | 132篇 |
2005年 | 104篇 |
2004年 | 112篇 |
2003年 | 109篇 |
2002年 | 88篇 |
2001年 | 74篇 |
2000年 | 76篇 |
1999年 | 57篇 |
1998年 | 16篇 |
1997年 | 13篇 |
1996年 | 18篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 13篇 |
1992年 | 40篇 |
1991年 | 54篇 |
1990年 | 43篇 |
1989年 | 36篇 |
1988年 | 27篇 |
1987年 | 28篇 |
1986年 | 32篇 |
1985年 | 29篇 |
1984年 | 29篇 |
1983年 | 19篇 |
1982年 | 17篇 |
1981年 | 20篇 |
1980年 | 11篇 |
1979年 | 19篇 |
1978年 | 10篇 |
1976年 | 10篇 |
1973年 | 11篇 |
1972年 | 10篇 |
1969年 | 9篇 |
1968年 | 12篇 |
排序方式: 共有2527条查询结果,搜索用时 15 毫秒
971.
Ikeda N Yamada K Shibuya T Kashiwada A Matsuda K Hirata M 《Bioscience, biotechnology, and biochemistry》2008,72(5):1368-1371
Alkylphenols were effectively treated with horseradish peroxidase at pH 7.0 and 30 degrees C in the presence of H(2)O(2) and poly(ethylene glycol) irrespective of the relative position or isomeric form of the alkyl chains. Water-insoluble oligomer precipitates were readily filtered out after enzymatic treatment, and transparent and colorless solutions were obtained for all p- and m-alkylphenols used. 相似文献
972.
Yamamoto K Sato Y Ishimori A Miyairi K Okuno T Nemoto N Shimizu H Kidokoro S Hashimoto M 《Bioscience, biotechnology, and biochemistry》2008,72(8):2039-2048
D-Trigalacturonic acid methylglycoside (3) was synthesized to evaluate the previously synthesized sulfur analogue 1 by comparison. The NOE experiments revealed that both 3 and 1 took on a similar conformation around their glycosyl linkage. 相似文献
973.
Norihiro Yoshimura Hirotaka Ohara Katsuyuki Miyabe Tessin Ban Hitoshi Sano Itaru Naitoh Kazuki Hayashi Tomoaki Ando Takahiro Nakazawa Takashi Joh 《International Seminars in Surgical Oncology : ISSO》2008,5(1):19
Background
Although GIST generally occurs in the digestive tract, such as the stomach, and small and small intestine primarily, Omental GIST tumours are very rare.Case Presentation
A 63-year-old male patient, who recognized an abdominal tumor 1 year before admission, had a slight expansion of the tumor, reduction of the body and malaise, was consulted to our hospital. Abdominal CT and MRI revealed a cystic lesion of 26 cm in diameter with a clear boundary from immediately below the interseptum to the pelvic cavity, and imaged the septum and cystic wall. We considered that the patient had a cystic tumor in the abdomen, of which the primary lesion was unknown, and scheduled surgery. The patient unfortunately deteriorated with shock and sudden pain in the abdomen. Wediagnosed tumor rapture, and emergency surgery was performed. The tumor, weighing 3,600 g, was mostly cystic, and filled with sanguinous fluid and clot. Histologically, the tumor was composed of spindle cells, and was positive for c-KIT (CD117), slightly positive for alpha-smooth muscle actin (SMA), and S-100 protein positive. Based on these findings, the tumor was diagnosed as GIST primarily occurring in the greater omentum.Conclusion
We experienced a rare case of GIST which originated from the greater omentum. Recently, the prognosis of GIST has been improved since the treatment with Imatinib.It is necessary to consider the diagnosis of GIST on encountering a mass in the greater omentum.974.
Genetic variation in rice 总被引:2,自引:0,他引:2
Completion of the genomic sequencing of rice has enhanced the discovery of new genes. Wild rice relatives are good sources for extending the genetic variation of cultivated rice. Reproductive barriers are commonly found in distant crosses of rice and are attracting attention. The combination of genetic analyses and molecular tools has greatly facilitated the molecular cloning of rice genes based on the classical approach and enabled the tracking of dissemination of the alleles for domestication. Basic information for population genetics study in rice is still being collected and is expected to provide an alternative approach for finding new genes. The wide genetic variation available in wild rice relatives and the combination of various genetic approaches will allow the analysis and understanding of genetic variation at the nucleotide sequence level, as well as the discovery of novel alleles by sequence-based approaches. 相似文献
975.
The chemoprotective effect of hydroxytyrosol (HT) against Sudan I-induced genotoxicity was investigated in a human hepatoma cell line, HepG2. The comet assay and micronucleus (MN) assay were used to monitor genotoxicity. Intracellular reactive oxygen species (ROS) formation was measured using a fluorescent probe, 2,7-dichlorofluorescein diacetate (DCFH-DA). The levels of oxidative DNA damage and lipid peroxidation were estimated by immunocytochemistry analysis of 8-hydroxydeoxyguanosine (8-OHdG) and by measuring levels of thiobarbituric acid-reactive substances (TBARS), respectively. Intracellular glutathione (GSH) level was estimated by fluorometric methods. The results showed that HT significantly reduced the genotoxicity caused by Sudan I. Furthermore, HT ameliorated lipid pexidation as demonstrated by a reduction in TBARS formation and attenuated GSH depletion in a concentration-dependent manner. It was also found that HT reduced intracellular ROS formation and 8-OHdG level caused by Sudan I. These results strongly suggest that HT has significant protective ability against Sudan I-induced genotoxicity. 相似文献
976.
Tatsuya Kato Kotaro Kikuta Ayumi Kanematsu Sachiko Kondo Hirokazu Yagi Koichi Kato Enoch Y. Park 《Biotechnology letters》2017,39(9):1299-1308
Objective
To synthesize complex type N-glycans in silkworms, shRNAs against the fused lobe from Bombyx mori (BmFDL), which codes N-acetylglucosaminidase (GlcNAcase) in the Golgi, was expressed by recombinant B. mori nucleopolyhedrovirus (BmNPV) in silkworm larvae.Results
Expression was under the control of the actin promoter of B. mori or the U6-2 and i.e.-2 promoters from Orgyia pseudotsugata multiple nucleopolyhedrovirus (OpMNPV). The reduction of specific GlcNAcase activity was observed in Bm5 cells and silkworm larvae using the U6-2 promoter. In silkworm larvae, the partial suppression of BmFDL gene expression was observed. When shRNA against BmFDL was expressed under the control of U6-2 promoter, the Man3GlcNAc(Fuc)GlcNAc structure appeared in a main N-glycans of recombinant human IgG. These results suggested that the control of BmFDL expression by its shRNA in silkworms caused the modification of its N-glycan synthetic pathway, which may lead to the alteration of N-glycans in the expressed recombinant proteins.Conclusions
Suppression of BmFDL gene expression by shRNA is not sufficient to synthesize complex N-glycans in silkworm larvae but can modify the N-glycan synthetic pathway.977.
Allotetraploid cryptic species in Asplenium normale in the Japanese Archipelago,detected by chemotaxonomic and multi‐locus genotype approaches
下载免费PDF全文
![点击此处可从《American journal of botany》网站下载免费的PDF全文](/ch/ext_images/free.gif)
978.
Ayumi Mori Hiroshi Sato Megumi Kasai Tetsuya Yamada Akira Kanazawa 《Transgenic research》2017,26(3):349-362
The expression of transgenes introduced into a plant genome is sometimes suppressed by RNA silencing. Although local and systemic spread of RNA silencing have been studied, little is known about the mechanisms underlying spatial and temporal variation in transgene silencing between individual plants or between plants of different generations, which occurs seemingly stochastically. Here, we analyzed the occurrence, spread, and transmission of RNA silencing of the green fluorescent protein (GFP) gene over multiple generations of the progeny of a single soybean transformant. Observation of GFP fluorescence in entire plants of the T3–T5 generations indicated that the initiation and subsequent spread of GFP silencing varied between individuals, although this GFP silencing most frequently began in the primary leaves. In addition, GFP silencing could spread into the outer layer of seed coat tissues but was hardly detectable in the embryos. These results are consistent with the notion that transgene silencing involves its reset during reproductive phase, initiation after germination, and systemic spread in each generation. GFP silencing was absent in the pulvinus, suggesting that its cortical cells inhibit cell-to-cell spread or induction of RNA silencing. The extent of GFP silencing could differ between the stem and a petiole or between petiolules, which have limited vascular bundles connecting them and thus deter long-distant movement of silencing. Taken together, these observations indicate that the initiation and/or spread of RNA silencing depend on specific features of the architecture of the plant in addition to the mechanisms that can be conserved in higher plants. 相似文献
979.
980.
Reconstitution is one of the most fundamental and powerful tools to investigate pigment—protein complexes, for example, light-harvesting complexes and reaction center complexes. Two reconstitution methods, in vitro and in vivo, have been applied to complexes. In vitro reconstitution methods were first developed using isolated proteins and pigments, and recently using over-expressed proteins. This method enables analysis of pigment binding, pigment stoichiometry, and protein flexibility when accepting extrinsic pigments, however, it has not yet been successfully applied to the core antenna system. In vivo reconstitution, which was developed using genetic modifications, is applicable even on core systems. In this Review, the in vivo reconstitution is mainly considered on the basis of the in vitro reconstitution, because the former was a recent development and will be expanded to many systems. When genes for a new pigment are acquired and expressed, the new pigment is incorporated into a pre-exiting complex(es) and becomes functional when it is accepted by this complex(es), or abandoned if it is not. This process is postulated to occur during the evolutionary process(es) of antenna and reaction centers, and it is now possible to reproduce this evolutionary developmental pathway(s). Several examples of in vivo reconstitution are given and considered from the viewpoint of evolutionary implication with regards to the antenna and reaction centers.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献