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排序方式: 共有677条查询结果,搜索用时 468 毫秒
61.
M. Luisa Molina A. Marcela Giudici José A. Poveda Gregorio Fernández-Ballester Estefanía Montoya M. Lourdes Renart Asia M. Fernández José A. Encinar Gloria Riquelme Andrés Morales José M. González-Ros 《The Journal of biological chemistry》2015,290(42):25745-25755
There is increasing evidence to support the notion that membrane proteins, instead of being isolated components floating in a fluid lipid environment, can be assembled into supramolecular complexes that take part in a variety of cooperative cellular functions. The interplay between lipid-protein and protein-protein interactions is expected to be a determinant factor in the assembly and dynamics of such membrane complexes. Here we report on a role of anionic phospholipids in determining the extent of clustering of KcsA, a model potassium channel. Assembly/disassembly of channel clusters occurs, at least partly, as a consequence of competing lipid-protein and protein-protein interactions at nonannular lipid binding sites on the channel surface and brings about profound changes in the gating properties of the channel. Our results suggest that these latter effects of anionic lipids are mediated via the Trp67–Glu71–Asp80 inactivation triad within the channel structure and its bearing on the selectivity filter. 相似文献
62.
Yumi Ueki Michael A Hadders Melanie B Weisser Isha Nasa Paula SoteloParrilla Lauren E Cressey Tanmay Gupta Emil P T Hertz Thomas Kruse Guillermo Montoya A Arockia Jeyaprakash Arminja Kettenbach Susanne M A Lens Jakob Nilsson 《EMBO reports》2021,22(7)
The shugoshin proteins are universal protectors of centromeric cohesin during mitosis and meiosis. The binding of human hSgo1 to the PP2A‐B56 phosphatase through a coiled‐coil (CC) region mediates cohesion protection during mitosis. Here we undertook a structure function analysis of the PP2A‐B56‐hSgo1 complex, revealing unanticipated aspects of complex formation and function. We establish that a highly conserved pocket on the B56 regulatory subunit is required for hSgo1 binding and cohesion protection during mitosis in human somatic cells. Consistent with this, we show that hSgo1 blocks the binding of PP2A‐B56 substrates containing a canonical B56 binding motif. We find that PP2A‐B56 bound to hSgo1 dephosphorylates Cdk1 sites on hSgo1 itself to modulate cohesin interactions. Collectively our work provides important insight into cohesion protection during mitosis. 相似文献
63.
L.R. Comini I.M. Fernandez N.B. Rumie VittarS.C. Núñez Montoya J.L. Cabrera V.A. Rivarola 《Phytomedicine》2011,18(12):1093-1095
Searching for agents that could be effective in the treatment of cancer, special highlight has focused on the study of numerous plant-derived compounds. We previously demonstrated that anthraquinones (AQs) isolated from a vegetal species: Heterophyllaea pustulata Hook f. (Rubiaceae), such as rubiadin, rubiadin-1-methyl ether, soranjidiol, soranjidiol-1-methyl ether exhibit photosensitizing properties without antecedents as photodynamic agents in malignant cells. In the present study, we investigated the potential role of these AQs as a phototoxic agent against human breast carcinoma using MCF-7c3 cells. All AQs exhibited significant photocytotoxicity on cancer cells at the concentration of 100 μM with 1 J/cm2 light dose, resulting soranjidiol-1-methyl ether in complete cell destruction. The observed cellular killing by photoactivated AQs exhibited close relation with singlet oxygen production, except for soranjidiol-1-methyl ether, where cell viability decrease is in relation to uptake by tumor cells. 相似文献
64.
Rodriguez D Ramesh C Henson LH Wilmeth L Bryant BK Kadavakollu S Hirsch R Montoya J Howell PR George JM Alexander D Johnson DL Arterburn JB Shuster CB 《Bioorganic & medicinal chemistry》2011,19(18):5446-5453
Assembly of a bipolar mitotic spindle requires the action of class 5 kinesins, and inhibition or depletion of this motor results in mitotic arrest and apoptosis. S-Trityl-l-cysteine is an allosteric inhibitor of vertebrate Kinesin Spindle Protein (KSP) that has generated considerable interest due to its anti-cancer properties, however, poor pharmacological properties have limited the use of this compound. We have modified the triphenylmethyl and cysteine groups, guided by biochemical and cell-based assays, to yield new cysteinol and cysteamine derivatives with increased inhibitory activity, greater efficacy in model systems, and significantly enhanced potency against the NCI60 tumor panel. These results reveal a promising new class of conformationally-flexible small molecules as allosteric KSP inhibitors for use as research tools, with activities that provide impetus for further development as anti-tumor agents. 相似文献
65.
George S. Mahuku María Antonia Henríquez Carmenza Montoya Carlos Jara Henry Teran Stephen Beebe 《Molecular breeding : new strategies in plant improvement》2011,28(1):57-71
Angular leaf spot (ALS) is one of the major diseases of the common bean (Phaseolus vulgaris L.). Different sources of resistance have been identified but few have been characterized. Studies were conducted to elucidate
the inheritance of ALS resistance in the bean accession G10909 and to identify molecular markers linked to these genes. Evaluation
of parental genotypes, F1, F2 and backcross to susceptible parent (Sprite) populations revealed that two dominant and complementary genes conditioned ALS
resistance. Allelism tests showed that the ALS resistance genes in G10909 were different from those in the Mesoamerican cultivars
Mexico 54, MAR 2, G10474 and Cornell 49-242. Three sequence-characterized amplified region (SCAR) markers, PF13310, PF9260 and OPE04709, and a microsatellite, Pv-gaat001, segregated in coupling with the resistance genes in G10909. Pairwise segregation analysis
revealed that markers PF13310, PF9260 and OPE04709 were linked, while Pv-gaat001 segregated in a 9:3:3:1 ratio from all markers. Markers PF13310, PF9260 and OPE04709 were mapped to linkage group B08, and segregated with resistance gene Phg
G10909B
at 4.9, 7.4 and 9.9 cM, respectively. Pv-gaat001, previously mapped to linkage group B04, segregated with resistance gene
Phg
G10909A
at 13 cM. The potential utility of these markers to aid breeding for ALS resistance is discussed. 相似文献
66.
67.
siRNA (small interfering RNA) and shRNA (small hairpin RNA) are powerful and commonly used tools in biomedical research. Currently, siRNAs are generally designed as two 21 nt strands of RNA that include a 19 nt completely complementary part and a 2 nt overhang. However, since the si/shRNAs use the endogenous miRNA machinery for gene silencing and the miRNAs are generally 22 nt in length and contain multiple internal mismatches, we tested if the functionality can be increased by designing the si/shRNAs to mimic a miRNA structure. We systematically investigated the effect of single or multiple mismatches introduced in the passenger strand at different positions on siRNA functionality. Mismatches at certain positions could significantly increase the functionality of siRNAs and also, in some cases decreased the unwanted passenger strand functionality. The same strategy could also be used to design shRNAs. Finally, we showed that both si and miRNA structured oligos (siRNA with or without mismatches in the passenger strand) can repress targets in all individual Ago containing cells, suggesting that the Ago proteins do not differentiate between si/miRNA-based structure for silencing activity. 相似文献
68.
69.
Reactions of ligands 1-ethyl-5-methyl-3-phenyl-1H-pyrazole (L1) and 5-methyl-1-octyl-3-phenyl-1H-pyrazole (L2) with [PdCl2(CH3CN)2 and K2PtCl4 gave complexes trans-[MCl2(L)2] (L = L1, L2). The new complexes were characterised by elemental analyses, conductivity measurements, infrared, 1H and 13C{1H} NMR spectroscopies and X-ray diffraction. The NMR study of the complex [PdCl2(L1)2], in CDCl3 solution, is consistent with a very slow rotation of ligands around the Pd-N bond, so that two conformational isomers can be observed in solution (syn and anti). Different behaviour is observed for complexes [PdCl2(L2)2] and [PtCl2(L)2] (L = L1, L2), which present an isomer in solution at room temperature (anti). The crystal structure of [PdCl2(L1)2] complex is described, where the Pd(II) presents a square planar geometry with the ligands coordinated in a trans disposition. 相似文献
70.
Two new pyrazole-derived ligands, 1-ethyl-3,5-bis(2-pyridyl)pyrazole (L1) and 1-octyl-3,5-bis(2-pyridyl)pyrazole (L2), both containing alkyl groups at position 1 were prepared by reaction between 3,5-bis(2-pyridyl) pyrazole and the appropriate bromoalkane in toluene using sodium ethoxide as base.The reaction between L1, L2 and [MCl2(CH3CN)2] (M = Pd(II), Pt(II)) resulted in the formation complexes of formula [MCl2(L)] (M = Pd(II), L = L1 (1); M = Pd(II), L = L2 (2); M = Pt(II), L = L1 (3); M = Pt(II), L = L2 (4)). These complexes were characterised by elemental analyses, conductivity measurements, infrared, 1H, 13C{1H} NMR and HMQC spectroscopies. The X-ray structure of the complex [PtCl2(L2)] (4) was determined. In this complex, Npyridine and Npyrazole donor atoms coordinate the ligand to the metal, which complete its coordination with two chloro ligands in a cis disposition. 相似文献