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61.
62.
Rot1 is an essential yeast protein originally shown to be implicated in such diverse processes such as β-1,6-glucan synthesis, actin cytoskeleton dynamics or lysis of autophagic bodies. More recently also a role as a molecular chaperone has been discovered. Here, we report that Rot1 interacts in a synthetic manner with Ost3, one of the nine subunits of the oligosaccharyltransferase (OST) complex, the key enzyme of N-glycosylation. The deletion of OST3 in the rot1-1 mutant causes a temperature sensitive phenotype as well as sensitivity toward compounds interfering with cell wall biogenesis such as Calcofluor White, caffeine, Congo Red and hygromycin B, whereas the deletion of OST6, a functional homolog of OST3, has no effect. OST activity in vitro determined in membranes from rot1-1ost3Δ cells was found to be decreased to 45% compared with wild-type membranes, and model glycoproteins of N-glycosylation, like carboxypeptidase Y, Gas1 or dipeptidyl aminopeptidase B, displayed an underglycosylation pattern. By affinity chromatography, a physical interaction between Rot1 and Ost3 was demonstrated. Moreover, Rot1 was found to be involved also in the O-mannosylation process, as the glycosylation of distinct glycoproteins of this type were affected as well. Altogether, the data extend the role of Rot1 as a chaperone required to ensure proper glycosylation. 相似文献
63.
IgG opsonization of HIV impedes provirus formation in and infection of dendritic cells and subsequent long-term transfer to T cells 总被引:3,自引:0,他引:3
Wilflingseder D Banki Z Garcia E Pruenster M Pfister G Muellauer B Nikolic DS Gassner C Ammann CG Dierich MP Piguet V Stoiber H 《Journal of immunology (Baltimore, Md. : 1950)》2007,178(12):7840-7848
Already at initial phases of infection, HIV is coated with complement fragments. During the chronic phase, when HIV-specific IgGs appear, the virus circulates immune complexed with IgG and complement. Thus, we studied the interaction of dendritic cells (DCs) and DC-T cell cocultures with complement (C)-opsonized and C-IgG-opsonized HIV. HIV infection of monocyte-derived DCs and circulating BDCA-1-positive DCs was significantly reduced upon the presence of virus-specific but non-neutralizing IgGs. DCs exposed to C-Ig-HIV or IgG-opsonized HIV showed an impaired provirus formation and p24 production and a decreased transmission rate to autologous nonstimulated T cells upon migration along a chemokine gradient. This reduced infectivity was also observed in long-term experiments, when T cells were added delayed to DCs exposed to IgG-coated HIV without migration. Similar kinetics were seen when sera from HIV-1-infected individuals before and after seroconversion were used in infection assays. Both C- and C-IgG-opsonized HIV were captured and targeted to a tetraspanin-rich endosome in immature DCs, but differed with respect to MHC class II colocalization. The reduced infection by IgG-opsonized HIV is possibly due to interactions of virus-bound IgG with FcgammaRIIb expressed on DCs. Therefore, the intracellular fate and transmission of immune-complexed HIV seems to differ depending on time and opsonization pattern. 相似文献
64.
Shalak V Guigou L Kaminska M Wautier MP Wautier JL Mirande M 《The Journal of biological chemistry》2007,282(15):10935-10943
In human, nine aminoacyl tRNA synthetases are associated with the three auxiliary proteins, p18, p38, and p43, to form a stable multiprotein complex. The p43 component, which has a potent tRNA binding capacity, is associated to the complex via its N-terminal moiety. This protein is also the precursor of the endothelial monocyte-activating polypeptide II (p43(EMAPII), corresponding to the C-terminal moiety of p43), a cytokine generated during apoptosis. Here we examined the cellular pathway that, starting from the p43 subunit of the complex, leads to this extracellular cytokine. We identified a new intermediate in this pathway, named p43(ARF) for Apoptosis-released Factor. This intermediate is produced in cellulo by proteolytic cleavage of endogenous p43 and is rapidly recovered in the culture medium. This p43 derivative was purified from the medium of human U937 cells subjected to serum starvation. It contains 40 additional N-terminal amino acid residues as compared with the cytokine p43(EMAPII) and may be generated by a member of the matrix metalloproteinase family. Recombinant p43(ARF) is a monomer in solution and binds tRNA with a Kd of approximately 6 nM, 30-fold lower than that of p43. Highly purified p43(ARF) or p43(EMAPII) do not stimulate the expression of E-selectin by human umbilical vein endothelial cells. Our results suggest that the cleavage of p43 and its cellular delocalization, and thus the release of this tRNA binding subunit from the complex, is one of the molecular mechanisms leading to the shut down of protein synthesis in apoptosis. 相似文献
65.
Hyvönen R Agren GI Linder S Persson T Cotrufo MF Ekblad A Freeman M Grelle A Janssens IA Jarvis PG Kellomäki S Lindroth A Loustau D Lundmark T Norby RJ Oren R Pilegaard K Ryan MG Sigurdsson BD Strömgren M van Oijen M Wallin G 《The New phytologist》2007,173(3):463-480
Temperate and boreal forest ecosystems contain a large part of the carbon stored on land, in the form of both biomass and soil organic matter. Increasing atmospheric [CO2], increasing temperature, elevated nitrogen deposition and intensified management will change this C store. Well documented single-factor responses of net primary production are: higher photosynthetic rate (the main [CO2] response); increasing length of growing season (the main temperature response); and higher leaf-area index (the main N deposition and partly [CO2] response). Soil organic matter will increase with increasing litter input, although priming may decrease the soil C stock initially, but litter quality effects should be minimal (response to [CO2], N deposition, and temperature); will decrease because of increasing temperature; and will increase because of retardation of decomposition with N deposition, although the rate of decomposition of high-quality litter can be increased and that of low-quality litter decreased. Single-factor responses can be misleading because of interactions between factors, in particular those between N and other factors, and indirect effects such as increased N availability from temperature-induced decomposition. In the long term the strength of feedbacks, for example the increasing demand for N from increased growth, will dominate over short-term responses to single factors. However, management has considerable potential for controlling the C store. 相似文献
66.
Pheromone peptides are an important component of bacterial quorum‐sensing system. The pheromone peptide cOB1 (VAVLVLGA) of native commensal Enterococcus faecalis has also been identified as an antimicrobial peptide (AMP) and reported to kill the prototype clinical isolate strain of E. faecalis V583. In this study, the pheromone peptide cOB1 has shown to form amyloid‐like structures, a characteristic which is never reported for a pheromone peptide so far. With in silico analysis, the peptide was predicted to be highly amyloidogenic. Further, under experimental conditions, cOB1 formed aggregates displaying characteristics of amyloid structures such as bathochromic shift in Congo red absorbance, enhancement in thioflavin T fluorescence, and fibrillar morphology under transmission electron microscopy. This novel property of pheromone peptide cOB1 may have some direct effects on the binding of the pheromone to the receptor cells and subsequent conjugative transfer, making this observation more important for the therapeutics, dealing with the generation of virulent and multidrug‐resistant pathogenic strains. 相似文献
67.
Plasmonics - Long-range surface plasmon resonance (LRSPR)-based sensors exhibit high sensitivity as compared to the conventional SPR sensors due to low losses. A high refractive index prism and low... 相似文献
68.
Hein Anke Brenner Sarah Polsakiewicz Monika Knoop Volker 《Plant molecular biology》2020,102(1-2):185-198
Plant Molecular Biology - Upon loss of either its chloroplast or mitochondrial target, a uniquely dual-targeted factor for C-to-U RNA editing in angiosperms reveals low evidence for improved... 相似文献
69.
Jain Surbhi Paliwal Ayushi Gupta Vinay Tomar Monika 《Plasmonics (Norwell, Mass.)》2020,15(4):1091-1101
Plasmonics - The present study focuses on the employment of TiO2 (titanium dioxide) film as an anti-reflective coating (ARC) on thin crystalline silicon (Si)-based solar cells along with the... 相似文献
70.
Monika M. Lulsdorf Hans Rempel Jennie A. Jackson David S. Baliski Shaun L. A. Hobbs 《Plant cell reports》1991,9(9):479-483
For optimization of the transformation procedure with Pisum sativum L. stern explant callus was used to test the effect of disarmed Agrobacterium tumefaciens strains, cocultivation procedures (preconditioning of explants; use of Nicotiana tabacum L. nurse cultures), duration of cocultivation (2, 3 or 4 days), and agents for selection (kanamycin or hygromycin). The succinamopine strain EHA101(pBI1042) produced the highest percentage of transformed calli (77%) when used in conjunction with tobacco nurse culture during four days of cocultivation. Using this strain, kanamycin (76%) and hygromycin (77%) were equally effective selective agents, but for strain LBA4404(pBI1042) percentage of transformed calli was higher for hygromycin (63%) than for kanamycin (17%). The procedures and strains shown to be optimal for transformation of pea callus will now be complemented by a pea regeneration system. 相似文献