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1.
The idiotypic network theory (N. K. Jerne, Ann. Immunol. 125, 373-389, 1974) predicts that any antibody that can be made by an individual would have its preexisting specific complementary B cells in its germline repertoire. We transplanted syngeneic BALB/c mice with live hybridoma cells and demonstrated the simultaneous presence of interacting idiotypic and anti-idiotypic B cells in an individual animal by immuno-cytoadherence assays. Furthermore, we demonstrate that interacting B cells displaying idiotypic and anti-idiotypic antibodies are subjected to lysis by complement. It is therefore tempting to speculate that this complement-sensitive interaction between idiotypic and complementary anti-idiotypic B cells in vivo may provide a mechanism for the regulation of B cell populations. 相似文献
2.
Z L Hegedus H A Frank T I Steinman M D Altschule U Nayak 《Archives internationales de physiologie et de biochimie》1988,96(5):211-221
The fluorescence excitation and emission spectra observed in plasma from patients with chronic renal failure were reproduced by the generation of soluble lipofuscins in normal plasma samples by incubation with mixtures of L-dopa, dopamine, L-norepinephrine, L-epinephrine, 3-hydroxy-DL-kynurenine and 3-hydroxy-anthranilic acid for 24 h at 37 degrees C. Relative fluorescence intensity measurements consistently showed elevated plasma levels of the soluble lipofuscins in chronic renal failure: the means (n = 27) were 73.9 +/- 33.4 (SD) and 71.1 +/- 14.8 at emissions 413 nm and 445 nm respectively, in contrast to those of normal plasma samples (n = 11), 18.2 +/- 5.3 and 23.1 +/- 5.6. The maximum or shoulder at approximately 413 nm represents soluble lipofuscin that can be generated from 3-hydroxyanthranilic acid and the maximum or shoulder at approximately 445 nm represents soluble lipofuscins derived from the precursors listed above and probably from other related precursors. Gravimetric measurements also showed elevated levels of melanins in the plasma samples of patients with chronic renal failure: 2.72 +/- 0.38 mg/ml (n = 16), as compared to normal values: 1.70 +/- 0.10 mg/ml (n = 6). In individual patients haemodialysis reduced the fluorescence intensities to a range of 65-99% and the melanin levels to a range of 86-99% of the pre-dialysis values. 相似文献
3.
The high molecular weight aminoacyl-tRNA synthetase complex (the 24S complex) was isolated from rat liver by ultracentrifugation. The lysyl-tRNA synthetase (E.C. 6.1.1.6) was selectively dissociated by hydrophobic interaction chromatography on 1,6 diaminohexyl agarose followed by hydroxylapatite chromatography and DEAE chromatography. The lysyl-tRNA synthetase dissociated from the 24S synthetase complex was purified approximately to 2700 fold with 14% yield. 相似文献
4.
P. Nayak 《Journal of Phytopathology》1986,116(2):162-166
Twenty isolates of Xanthomonas campestris pv. oryzae (Ishiyama) Dye each from susceptible and resistant rice cultivars, were inoculated on the susceptible genotype IR-8 and resistant M Sungsong to measure the impact of host selection pressure on virulence change. Isolates virulent on resistant genotype tended to be less adaptive on susceptible cultivars. While isolates from susceptible genotype showed 2.2 times more general virulence (GV) than specific virulence (SV), isolates of resistant host origin had only 1.3 times GV, indicating that the resistant host plant displays considerable increase in virulence. The SV value increased 1.64 times after one cropping with resistants indicated the potential of the pathogen to change to be slow. 相似文献
5.
Complete nucleotide sequence of the nucleoprotein gene of influenza B virus. 总被引:7,自引:4,他引:3 下载免费PDF全文
A DNA copy of influenza B/Singapore/222/79 viral RNA segment 5, containing the gene coding for the nucleoprotein (NP), has been cloned in Escherichia coli plasmid pBR322, and its nucleotide sequence has been determined. The influenza B NP gene contains 1,839 nucleotides and codes for a protein of 560 amino acids with a molecular weight of 61,593. Comparison of the influenza B NP amino acid sequence with that of influenza A NP (A/PR/8/34) reveals 37% direct homology in the aligned regions, indicating a common ancestor. However, influenza B NP has an additional 50 amino acids at its N-terminal end. As is the case with influenza A NP, influenza B NP is a basic protein, with its charged residues relatively evenly distributed rather than clustered. The structural homology suggests functional similarity between the NP of influenza A and B viruses. 相似文献
6.
Influenza virus hemagglutinin expression is polarized in cells infected with recombinant SV40 viruses carrying cloned hemagglutinin DNA 总被引:35,自引:0,他引:35
Primary cell cultures of African Green monkey kidney (AGMK) contain polarized epithelial cells in which influenza virus matures predominantly at the apical surfaces above tight junctions. Influenza virus glycoproteins were found to be localized at the same membrane domain from which the virus budded. When polarized primary AGMK cells were infected with recombinant SV40 viruses containing DNA coding for either an influenza virus H1 or H2 subtype hemagglutinin (HA), the HA proteins were preferentially expressed at the apical surface in a manner identical to that observed in influenza virus-infected cells. Thus, cellular mechanisms for sorting membrane glycoproteins recognize some structural feature of the HA glycoprotein itself, and other viral proteins are not necessary for this process. 相似文献
7.
R Nayak 《Biochemical and biophysical research communications》1992,184(1):467-470
5-Fluoro-2'-deoxyuridine is incorporated into DNA of mouse breast tumour in vivo. The incorporation is inhibited by thymidine. Part of the fluorodeoxyuridine is cleaved to fluorouracil and is incorporated into RNA. This incorporation is enhanced by thymidine. The result suggests that the major mechanism of action of the fluorouracil is due to its incorporation into RNA. 相似文献
8.
Influenza virus polymerase basic protein 1 interacts with influenza virus polymerase basic protein 2 at multiple sites. 总被引:2,自引:2,他引:0 下载免费PDF全文
Three polymerase proteins of influenza type A virus interact with each other to form the active polymerase complex. Polymerase basic protein 1 (PB1) can interact with PB2 in the presence or absence of polymerase acidic protein. In this study, we investigated the domains of PB1 involved in complex formation with PB2 in vivo, using coexpression and coimmunoprecipitation of the PB1-PB2 complex with monospecific antibodies. Results show that PB1 possesses at least two regions which can interact independently and form stable complexes with PB2. Both of these regions are located at the NH2 terminus of PB1; the COOH-terminal half of PB1 is not involved in interacting with PB2. Deletion analysis further demonstrated that the interacting regions of PB1 encompass amino acids (aa) 48 to 145 and aa 251 to 321. Linker insertions throughout the PB1 sequences did not affect complex formation with PB2. Deletion and linker-insertion mutants of PB1 were tested for polymerase activity in vivo. For this analysis, we developed a simplified assay for viral polymerase activity that uses a reporter chloramphenicol acetyltransferase gene containing the 5' and 3' ends of influenza viral promoter and nontranslating regions (minus sense) of the NS gene joined to a hepatitis delta virus ribozyme at its 3' end. This assay demonstrated that all deletion mutants of PB1 exhibited either background or greatly reduced polymerase activity irrespective of the ability to interact with PB2 and that all linker-insertion mutants except one at the extreme COOH end (L-746) of PB1 were also negative for viral polymerase activity. These results show that compared with complex formation of PB1 with PB2, the polymerase activity of PB1 was extremely sensitive to structural perturbation. 相似文献
9.
Three genotypes of chickpea ICCV-1, ICCV-6 and a Desi (local) variety were tested for plant regeneration through multiple shoot production. The embryo axis was removed from mature seeds, the root meristem and the shoot apex were discarded. These explants were cultured on medium containing MS macro salts, 4X MS micro salts, I35 vitamins, 3.0 mg/1 BAP, 0.004 mg/1 NAA, 3% (w/v) sucrose and incubated at 260C. The explants were transformed withAgrobacterium tumefaciens strain LBA4404 with binary vector pBI121 containing theuidA andnptIl genes. Multiple shoots were repeatedly selected with kanamycin. The selected kanamycin resistant shoots were rooted on MS medium supplemented with 0.05 mg/1 113A. The presumptive transformants histochemically stained positive for GUS. Additionally, nptll assay confirmed the expression ofnptII in kanamycin resistant plants. Transgenic plants were transferred to soil and grown in the green house.Abbreviations BAP
6-benzylamino purine
- 2,4-D
2,4dichlorophenoxy acetic acid
- IAA
Indole acetic acid
- IBA
Indole butaric acid
- NAA
Naphthalene acetic acid 相似文献
10.
Immune response to human influenza virus hemagglutinin expressed in Escherichia coli 总被引:9,自引:0,他引:9
Cloned DNA fragments coding for parts of strain WSN (H1N1) influenza virus hemagglutinin (HA) were fused to a bacterial leader DNA derived from the Escherichia coli trp operon. Fusion proteins produced consisted of 190 amino acids of trpLE' protein at the amino terminus, and HA amino acids, either 1-308, 1-396, or 1-548 (complete HA), at the carboxyl terminus. These proteins were expressed at high levels (10-20% of total protein) in E. coli starved for tryptophan. A CNBr fragment (HA1-211) was derived from HA-308. Each of the proteins was purified and used for immunizing mice and rabbits. The antibody produced was shown to bind to (i) the HA fusion proteins, (ii) detergent-treated viral HA, (iii) HA, on intact virions, and (iv) the HA on the surface of cells infected with influenza virus. This shows that the HA fusion proteins expressed in bacteria can elicit antibodies that recognize at least some determinants of the native viral HA, and probably could lead to development of an anti-influenza vaccine. 相似文献