全文获取类型
收费全文 | 930篇 |
免费 | 63篇 |
国内免费 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 18篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 13篇 |
2017年 | 12篇 |
2016年 | 20篇 |
2015年 | 43篇 |
2014年 | 45篇 |
2013年 | 61篇 |
2012年 | 77篇 |
2011年 | 80篇 |
2010年 | 50篇 |
2009年 | 34篇 |
2008年 | 72篇 |
2007年 | 73篇 |
2006年 | 71篇 |
2005年 | 71篇 |
2004年 | 67篇 |
2003年 | 42篇 |
2002年 | 41篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 9篇 |
1997年 | 8篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1981年 | 1篇 |
1974年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有994条查询结果,搜索用时 15 毫秒
1.
Taste sorting and naming: can taste concepts be misrepresented by traditional psychophysical labelling systems? 总被引:1,自引:0,他引:1
Japanese and American subjects were required to sort filterpapers, soaked in taste stimuli, into categories that had conceptuallythe same taste. Both Japanese and Americans sorted in the samemanner, indicating similar conceptualization. Taste names weregiven to the taste categories obtained by using the traditionalfour basic taste naming system, common in tastepsychophysics. This method was seen to underestimate the numberof categories actually present. This suggests a re-assessmentof current psychophysical taste-naming techniques. 相似文献
2.
A combined system of chemiluminescence detection and high performance liquid chromatography (CL–HPLC) was developed to determine primary peroxidation products in biological tissues, such as phosphatidylcholine hydroperoxide (PCOOH). The CL–HPLC assay consists of separation of lipid classes with HPLC and detection of hydroperoxide-specific chemiluminescence. Hydroperoxides react with heme compounds to produce oxidants as suggested by our early studies on tissue low-level chemiluminescence in which singlet molecular oxygen is generated as one of the excited species in several biological systems involving free radical events. In the CL–HPLC method, a cytochrome c–luminol mixture was used as a hydroperoxide-specific luminescent reagent, and the quantification of hydroperoxide was performed by detecting chemiluminescence due to the luminol oxidation caused by the oxidant produced during the lipid hydroperoxides with heme. The detection limit of PCOOH was 10 pmole hydroperoxide–O2. PCOOH in normal human blood was found to be 10–500 pmol/ml plasma and significantly higher levels of PCOOH were observed in some hospitalized patients. 相似文献
3.
Olaf Rieβ Claudia Kammerbauer Lutz Roewer Viktor Steimle Adriane Andreas Ekkehard Albert Tatsuo Nagai Jörg T. Epplen 《Immunogenetics》1990,32(2):110-116
We have investigated the extent of DNA variability in intronic simple (gt)n(ga)m repeat sequences and correlated this to sequence polymorphisms in the flanking exon 2 of HLA-DRB genes. The polymerase chain reaction (PCR) was used to amplify a DNA fragment containing exon 2 and the repeat region of intron 2. The PCR products were separated on sequencing gels in order to demonstrate length hypervariability of the (gt)n(ga)m repeats. In a parallel experiment, the PCR products were cloned and sequenced (each exon 2 plus adjacent simple repeats) to characterize the simple repeats in relation to the HLA-DRB sequences. In a panel of 25 DRB1, DRB4, and DRB5 alleles new sequences were not detected. Restriction fragment length polymorphism (RFLP) subtyping of serologically defined haplotypes corresponds to translated DNA sequences in 85% of the cases, the exceptions involving unusual DR/DQ combinations. Many identical DRB1 alleles can be distinguished on the basis of their adjacent simple repeats. We found group-specific organization of the repeats: the DRw52 supergroup repeats differ from those of DRB1*0101, DRB4*0101, and DRB5*0101 alleles and from those of pseudogenes. Finally, we amplified baboon DNA and found a DRB allele with extensive similarity to DRB1 sequences of the DRw52 supergroup. The simple repeat of the baboon gene, however, resembles that of human pseudogenes. In addition to further subtyping, the parallel study of polymorphic protein and hypervariable DNA alleles may allow conclusions to be drawn on the relationships between the DRB genes and perhaps also on the theory of trans-species evolution.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number M 34258. 相似文献
4.
Kazutoyo Osoegawa Rie Susukida Saishi Okano Jun Kudoh Shinsei Minoshima Nobuyoshi Shimizu Pieter J. de Jong Juergen Groet Jane Ives Hans Lehrach Dean Nizetic Eiichi Soeda 《Genomics》1996,32(3):375
The major phenotypic features of Down syndrome have been correlated with partial trisomies of chromosome 21, allowing us to define the candidate gene region to a 4-Mb segment on the 21q22.2 band. We present here a high-resolution physical map with megabase-sized cosmid/PAC contigs. This ordered clone library has provided unique material for the integration of a variety of mappable objects, including exons, cDNAs, restriction sites, etc. Furthermore, our results have exemplified a strategy for the completion of the chromosome 21 map to sequencing. 相似文献
5.
Denolf P Jansens S Peferoen M Degheele D Van Rie J 《Applied and environmental microbiology》1993,59(6):1828-1837
Binding of three Bacillus thuringiensis insecticidal crystal proteins (ICPs) to the midgut epithelium of Ostrinia nubilalis larvae was characterized by performing binding experiments with both isolated brush border membrane vesicles and gut tissue sections. Our results demonstrate that two independent ICP receptors are present in the brush border of O. nubilalis gut epithelium. From competition binding experiments performed with I-labeled and native ICPs it was concluded that CryIA(b) and CryIA(c) are recognized by the same receptor. An 11-fold-higher binding affinity of CryIA(b) for this receptor correlated with a 10-fold-higher toxicity of this ICP compared with CryIA(c). The CryIB toxin did not compete for the binding site of CryIA(b) and CryIA(c). Immunological detection of ingested B. thuringiensis ICPs on gut sections of O. nubilalis larvae revealed binding only along the epithelial brush border membrane. CryID and CryIE, two ICPs that are not toxic to O. nubilalis, were not bound to the apical microvilli of gut epithelial cells. In vitro binding experiments performed with native and biotinylated ICPs on tissue sections confirmed the correlation between ICP binding and toxicity. Moreover, by performing heterologous competition experiments with biotinylated and native ICPs, it was confirmed that the CryIB receptor is different from the receptor for CryIA(b) and CryIA(c). Retention of activated crystal proteins by the peritrophic membrane was not correlated with toxicity. Furthermore, it was demonstrated that CryIA(b), CryIA(c), and CryIB toxins interact in vitro with the epithelial microvilli of Malpighian tubules. In addition, CryIA(c) toxin also adheres to the basement membrane of the midgut epithelium. 相似文献
6.
Yoichi Tamai Hisako Kojima Shintaro Saito† Kikue Uchida Rie Kitajima Hiroshi Komatsu Tsuneo Moriya‡ 《Journal of neurochemistry》1993,60(5):1854-1863
Abstract: The metamorphic changes in levels of glycolipids and myelin proteins and 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) in the brains of bullfrog tadpoles, adult frogs, and axolotls were investigated, with particular emphasis on myelin maturation. The concentrations of cerebroside. sulfatide, and galactosyldiacylglycerol gradually increased from the onset of prometamorphosis throughout the active metamorphic period and then greatly increased after metamorphosis was completed. The ratio of glucocerebroside to galactocerebroside increased greatly in the prometamorphic period and then rapidly decreased to the frog level during the climax period. The fatty acid compositions of cerebroside and sulfatide showed a developmental change, with 24:1 being more predominant in the later metamorphic stage. The proportion of hydroxy fatty acids increased up to the onset of the prometamorphic stage and thereafter remained constant at ∼ 50% of the total. The CNP activity remained unchanged throughout metamorphosis at 60% that in frog myelin and increased in the adult frog. The composition of tadpole myelin proteins remained constant during metamorphosis, with large basic protein being the most abundant, and in the frog, proteolipid protein and large basic protein were present in comparable amounts. The two adult forms of axolotl, i.e., the neotenous and metamorphosed forms, exhibited almost identical myelin constituents, and CNP activity in the neotenous form amounted to one-fifth that in the bullfrog. These results indicate that active biosynthesis of myelin marker components occurs as metamorphosis proceeds, but more pronounced changes of myelin components occur after metamorphosis is completed. 相似文献
7.
Shigeki Furuya Miho Sera Rie Tohno-oka Kazuyuki Sugahara Koichiro Shiokawa Yoshio Hirabayashi 《Development, growth & differentiation》1995,37(3):337-346
The expression of heparan sulfate glycosaminoglycan (HS-GAG) was examined in Xenopus embryos during the developmental stages. Chemical analysis showed the existence of HS-GAG in the 35 S-labeled embryos. By western blot analysis using a specific anti-HS monoclonal antibody, HS-GAG related epitope was found after the neurulation on two protein bands, whose molecular weights were approximately 90 kDa and 100 kDa, respectively. Immunohistochemistry revealed that HS-GAG occurred exclusively in the animal hemisphere in early gastrulae, and then appeared predominantly on the sheath of the neural tube, the notochord and epithelium. To address whether HS-GAG chains contribute to Xenopus embryonic development, we eliminated the embryonic HS-GAG by injecting purified Flavobacterium heparitinases (HSase) into their blastocoels. Most of the injected embryos were aberrant in mesodermal and neural formation, and became acephalic. Histological examination showed that these embryos were completely devoid of the central nervous system and the mesodermal tissues. Neither heat-inactivated heparitinase nor chondroitinase showed such abnormality. The HS-GAG-eliminated embryos showed decreased expression of both muscular and neural-specific markers. These results suggest that HS-GAG plays an indispensable role in establishing the fundamental body plan during early Xenopus development. 相似文献
8.
Shin Masateru; Wakita Rie; Yamasaki Yohsuke; Oshino Reiko 《Plant & cell physiology》1981,22(2):343-346
The heavier form of ferredoxin-NADP+ reductase was extractedfrom spinach leaves or chloroplasts and isolated as the majorfraction at high ionic strengths with ammonium sulfate or sodiumchloride. At low ionic strengths, the form with the higher molecularweight was relatively unstable and was converted gradually intothe lower form. We concluded that the enzyme exists in vivoas the form with the higher molecular weight.
1Present address: Market Development Department, Shionogi &Co. LTD., 5-Sagisu, Fukushima-ku, Osaka 553, Japan. (Received December 16, 1980; Accepted January 19, 1981) 相似文献
9.
Terezie Mandáková Ale? Kova?ík Judita Zozomová-Lihová Rie Shimizu-Inatsugi Kentaro K. Shimizu Klaus Mummenhoff Karol Marhold Martin A. Lysak 《The Plant cell》2013,25(9):3280-3295
This article describes the use of cytogenomic and molecular approaches to explore the origin and evolution of Cardamine schulzii, a textbook example of a recent allopolyploid, in its ∼110-year history of human-induced hybridization and allopolyploidy in the Swiss Alps. Triploids are typically viewed as bridges between diploids and tetraploids but rarely as parental genomes of high-level hybrids and polyploids. The genome of the triploid semifertile hybrid Cardamine × insueta (2n = 24, RRA) was shown to combine the parental genomes of two diploid (2n = 2x = 16) species, Cardamine amara (AA) and Cardamine rivularis (RR). These parental genomes have remained structurally stable within the triploid genome over the >100 years since its origin. Furthermore, we provide compelling evidence that the alleged recent polyploid C. schulzii is not an autohexaploid derivative of C. × insueta. Instead, at least two hybridization events involving C. × insueta and the hypotetraploid Cardamine pratensis (PPPP, 2n = 4x−2 = 30) have resulted in the origin of the trigenomic hypopentaploid (2n = 5x−2 = 38, PPRRA) and hypohexaploid (2n = 6x−2 = 46, PPPPRA). These data show that the semifertile triploid hybrid can promote a merger of three different genomes and demonstrate how important it is to reexamine the routinely repeated textbook examples using modern techniques. 相似文献
10.
Kazushige Yamana Akira Yoshikawa Rie Noda Hidehiko Nakano 《Nucleosides, nucleotides & nucleic acids》2013,32(1-3):233-242
Abstract Incorporation of an azobenzene-4,4′-diamide group via a linker arm into the 3′-hydroxyl function of one oligonucleotide segment and the 5′-OH of other oligonucleotide has been described. The binding of the oligonucleotides containing the azobenzene linker was investigated by UV melting behaviors. The azobenzene linker has been shown to be useful as an effective bridge for stabilizing hairpin duplex and triplex. 相似文献