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941.
We present three novel mutations in the G6PD gene and discuss the changes they cause in the 3-dimensional structure of the enzyme: 573C-->G substitution that predicts Phe to Leu at position 191 in the C-terminus of helix alphae, 851T-->C mutation which results in the substitution 284Val--> -->Ala in the beta+alpha domain close to the C-terminal part of helix alphaj, and 1175T-->C substitution that predicts Ile to Thr change at position 392.  相似文献   
942.
Classical swine fever virus (CSFV) is often used as a surrogate model in molecular studies of the closely related hepatitis C virus. In this report we have examined the effect of the inhibition of glycosylation on the survival and maturation of CSFV. Viral glycoproteins (E(rns), E1, E2) form biologically active complexes - homo- and heterodimers, which are indispensable for viral life cycle. Those complexes are highly N-glycosylated. We studied the influence of N-glycosylation on dimer formation using E(rns) and E2 glycoproteins produced in insect cells after infection with recombinant baculoviruses. The glycoproteins were efficiently synthesized in insect cells, had similar molecular masses and formed dimers like their natural counterparts. Surprisingly, the addition of tunicamycin (an antibiotic which blocks early steps of glycosylation) to insect cell culture blocked not only dimer formation but it also led to an almost complete disappearance of E2 even in monomeric form. Tunicamycin did not exert a similar effect on the synthesis and formation of E(rns) dimers; the dimers were still formed, which suggests that E(rns) glycan chains are not necessary for dimer formation. We have also found that very low doses of tunicamycin (much lower than those used for blocking N-glycosylation) drastically reduced CSFV spread in SK6 (swine kidney) cell culture and the virus yield. These facts indicate that N-glycosylation inhibitors structurally similar to tunicamycin may be potential therapeutics for the inhibition of the spread of CSFV and related viruses.  相似文献   
943.
Protease-activated receptors (PARs) are involved in the contribution of airway epithelial cells to the development of inflammation by release of pro- and anti-inflammatory mediators. Here, we evaluated in epithelial cells the influence of LPS and continuous PAR activation on PAR expression level and the release of the proinflammatory chemokine IL-8. We studied primary human small airway epithelial cells and two airway epithelial cell lines, A549 and HBE cells. LPS specifically upregulated expression of PAR-2 but not of PAR-1. Exposure of epithelial cells to PAR-1 or PAR-2 agonists increased the PAR-1 expression level. The PAR-2 agonist exhibited higher potency than PAR-1 activators. However, the combined exposure of epithelial cells to LPS and PAR agonists abrogated the PAR-1 upregulation. The PAR-2 expression level was also upregulated after exposure to PAR-1 or PAR-2 agonists. This elevation was higher than the effect of PAR agonists on the PAR-1 level. In contrast to the PAR-1 level, the PAR-2 level remained elevated under concomitant stimulation with LPS and PAR-2 agonist. Furthermore, activation of PAR-2, but not of PAR-1, caused production of IL-8 from the epithelial cells. Interestingly, both in the epithelial cell line and in primary epithelial cells, there was a potentiation of the stimulation of the IL-8 synthesis and release by PAR-2 agonist together with LPS. In summary, these results underline the important role of PAR-2 in human lung epithelial cells. Moreover, our study shows an intricate interplay between LPS and PAR agonists in affecting PAR regulation and IL-8 production.  相似文献   
944.
Robust expansion of human hepatocytes in Fah-/-/Rag2-/-/Il2rg-/- mice   总被引:2,自引:0,他引:2  
Mice that could be highly repopulated with human hepatocytes would have many potential uses in drug development and research applications. The best available model of liver humanization, the uroplasminogen-activator transgenic model, has major practical limitations. To provide a broadly useful hepatic xenorepopulation system, we generated severely immunodeficient, fumarylacetoacetate hydrolase (Fah)-deficient mice. After pretreatment with a urokinase-expressing adenovirus, these animals could be highly engrafted (up to 90%) with human hepatocytes from multiple sources, including liver biopsies. Furthermore, human cells could be serially transplanted from primary donors and repopulate the liver for at least four sequential rounds. The expanded cells displayed typical human drug metabolism. This system provides a robust platform to produce high-quality human hepatocytes for tissue culture. It may also be useful for testing the toxicity of drug metabolites and for evaluating pathogens dependent on human liver cells for replication.  相似文献   
945.

The aim of the study was to examine the Braak’s hypothesis to explain the spreading and distribution of the neuropathological changes observed in the course of Parkinson’s disease among ascending neuroanatomical regions. We investigated the neurotransmitter levels (monoamines and amino acid concentration) as well as tyrosine hydroxylase (TH) and transglutaminase-2 (TG2) mRNA expression in the mouse striata (ST) after intracerebral α-synuclein (ASN) administration into gigantocellular reticular nucleus (Gi). Male C57BL/10 Tar mice were used in this study. ASN was administrated by stereotactic injection into Gi area (4 μl; 1 μg/μl) and mice were decapitated after 1, 4 or 12 weeks post injection. The neurotransmitters concentration in ST were evaluated using HPLC detection. TH and TG2 mRNA expression were examined by Real-Time PCR method. At 4 and 12 weeks after ASN administration we observed decrease of DA concentration in ST relative to control groups and we found a significantly higher concentration one of the DA metabolites—DOPAC. At these time points, we also noticed the increase in DA turnover determined as DOPAC/DA ratio. Additionally, at 4 and 12 weeks after ASN injection we noted decreasing of TH mRNA expression. Our findings corresponds with the Braak’s theory about the presence of the first neuropathological changes within brainstem and then with time affecting higher neuroanatomical regions. These results obtained after administration of ASN monomers to the Gi area may be useful to explain the pathogenesis of Parkinson’s disease.

  相似文献   
946.
The influence of concentration of simvastatin (SIM) on free radicals in A-2058 human melanoma malignum cells was studied. The proliferation assay for melanoma A-2058 cells with SIM in concentration range from 0.1 to 20 µM was performed. SIM in the concentrations of 0.1, 0.3, and 1 μM only slightly changed the growth of A-2058 cells, but the growth of the cells considerably decreased for higher concentrations of SIM. Free radicals in the cells were examined by an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. o-Semiquinone free radicals with g-factors in the range of 2.0060 to 2.0065 were found in A-2058 cells. The asymmetric broad EPR spectra with linewidths (ΔBpp) from 0.87 to 1.25 mT were measured. The fast spin-lattice relaxation processes characterized all the tested cells. The free radical concentrations in the all A-2058 cells cultured with SIM were lower than in the control cells. The quenching of free radicals in A-2058 cells depended on concentration of SIM. This effect was the weakest for concentration of SIM of 3 μM. The strongest decrease of free radical concentration caused SIM in concentration of 1 μM.  相似文献   
947.
Biological Trace Element Research - The aim of the study was to determine how inorganic and organic forms of zinc affect the concentrations of C-reactive protein (CRP), serum amyloid A (SAA),...  相似文献   
948.
Plant and Soil - Pseudo-metallophyte Silene vulgaris frequently colonizes polluted areas. We investigated whether plants obtained under in vitro conditions can be used to form long-term communities...  相似文献   
949.
Plant and Soil - Ethylene-insensitive mutation (ein)-conferred Arabidopsis tolerance to Cd has been reported. However, the mechanisms involved are far from clear. This study explores possible...  相似文献   
950.
Centella asiatica (L.) Urban is an important pharmacopoeial plant used not only in medicine but also in cosmetology. C. asiatica agitated shoot cultures were established to study the influence of ethephon, methyl jasmonate, L ‐phenylalanine (Eth 50 µM, MeJa 50 µM, L‐Phe 2.4 g/L of medium, respectively; seven variants of the supplementation) on the accumulation of secondary metabolites: the main centellosides (asiaticoside and madecassoside) and selected phenolic acids, and flavonoids in the biomass. Microshoots were harvested two and six days after the supplementation. Secondary metabolites were analyzed in methanolic extracts by UPLC‐MS/MS (centellosides) and by HPLC‐DAD (phenolics). In comparison with the reference cultures, the concentrations of individual secondary metabolites increased as follows: centellosides up to 5.6‐fold (asiaticoside), phenolic acids up to 122‐fold (p‐coumaric acid) and flavonoids up to 22.4‐fold (kaempherol). The highest production increase of individual compounds was observed for different variants of supplementation. Variant C (50 µM MeJa), the most optimal for centellosides and flavonoid accumulation, was selected for the experiment with bioreactors. Bioreactor Plantform?, compared to RITA® system and agitated cultures, appeared to be the most advantageous for secondary metabolites production in C. asiatica shoot cultures. The phenolic acid, flavonoid, centelloside, and total secondary metabolite productivity in Plantform? system is 1.8‐fold, 1.7‐fold, 2.8‐fold, 2.1‐fold, respectively, higher than in MeJa elicitated agitated cultures, and 4.3‐fold, 7.3‐fold, 12.2‐fold, 7.2‐fold, respectively, higher than in control agitated cultures.  相似文献   
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