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81.
哈尔滨西郊赤狐冬季巢区的初步研究 总被引:5,自引:2,他引:3
本文利用雪地跟踪方法对哈尔滨西郊5只赤狐在1985-1986年冬季的巢区做了观察。结果表明,5只狐对巢区内各部分使用的强度是不等的,对巢区中部的某些地块使用强度要高于对外围的使用,并具有明显的方向性。5个巢区的平均活动半径为320±68米至557±82米,面积为1.44-4.O9平方公里,线性指数为1.079至2。5只狐相邻距离约1000米。 相似文献
82.
Nonglucosylated oligosaccharides are transferred to protein in MI8-5 Chinese hamster ovary cells 总被引:3,自引:2,他引:1
A CHO mutant MI8-5 was found to synthesize Man9-GlcNAc2-P-P-dolichol rather
than Glc3Man9GlcNAc2-P-P-dolichol as the oligosaccharide-lipid intermediate
in N-glycosylation of proteins. MI8-5 cells were incubated with labeled
mevalonate, and the prenol was found to be dolichol. The mannose-labeled
oligosaccharide released from oligosaccharide-lipid of MI8-5 cells was
analyzed by HPLC and alpha-mannosidase treatment, and the data were
consistent with a structure of Man9GlcNAc2. In addition, MI8-5 cells did
not incorporate radioactivity into oligosaccharide- lipid during an
incubation with tritiated galactose, again consistent with MI8-5 cells
synthesizing an unglucosylated oligosaccharide-lipid. MI8-5 cells had
parental levels of glucosylphosphoryldolichol synthase activity. However,
in two different assays, MI8-5 cells lacked dolichol-
P-Glc:Man9GlcNAc2-P-P-dolichol glucosyltransferase activity. MI8-5 cells
were found to synthesize glucosylated oligosaccharide after they were
transfected with Saccharomyces cerevisiae ALG 6, the gene for
dolichol-P-Glc:Man9GlcNAc2-P-P-dolichol glucosyltransferase. MI8-5 cells
were found to incorporate mannose into protein 2-fold slower than parental
cells and to approximately a 2-fold lesser extent.
相似文献
83.
Persistent alterations in biomarkers of oxidative stress resulting from combined in Utero and neonatal manganese inhalation 总被引:4,自引:0,他引:4
Neonatal female and male rats were exposed to airborne manganese sulfate (MnSO4) during gestation and postnatal d 1–18. Three weeks post-exposure, rats were killed and we assessed biochemical end points
indicative of oxidative stress in five brain regions: cerebellum, hippocampus, hypothalamus, olfactory bulb, and striatum.
Glutamine synthetase (GS) protein levels, metallothionein (MT) and GS mRNA levels, and total glutathione (GSH) levels were
determined for all five regions. Overall, there was a statistically significant effect of manganese exposure on decreasing
brain GS protein levels (p=0.0061), although only the highest dose of manganese (1 mg Mn/m3) caused a significant increase in GS messenger RNA (mRNA) in both the hypothalamus and olfactory bulb of male rats and a
significant decrease in GS mRNA in the striatum of female rats. This highest dose of manganese had no effect on MT mRNA in
either males or females; however, the lowest dose (0.05 mg Mn/m3) decreased MT mRNA in the hippocampus, hypothalamus, and striatum in males. The median dose (0.5 mg Mn/m3) led to decreased MT mRNA in the hippocampus and hypothalamus of the males and olfactory bulb of the females. Overall, manganese
exposure did not affect total GSH levels, a finding that is contrary to those in our previous studies. Only the cerebellum
of manganese-exposed young male rats showed a significant reduction (p<0.05) in total GSH levels compared to control levels. These data reveal that alterations in biomarkers of oxidative stress
resulting from in utero and neonatal exposures of airborne managanese remain despite 3 wk of recovery; however, it is important to note that the
doses of manganese utilized represent levels that are 100-fold to a 1000-fold higher than the inhalation reference concentration
set by the US Environmental Protection Agency. 相似文献
84.
85.
Erez A Nagamani SC Shchelochkov OA Premkumar MH Campeau PM Chen Y Garg HK Li L Mian A Bertin TK Black JO Zeng H Tang Y Reddy AK Summar M O'Brien WE Harrison DG Mitch WE Marini JC Aschner JL Bryan NS Lee B 《Nature medicine》2011,17(12):1619-1626
Nitric oxide (NO) is crucial in diverse physiological and pathological processes. We show that a hypomorphic mouse model of argininosuccinate lyase (encoded by Asl) deficiency has a distinct phenotype of multiorgan dysfunction and NO deficiency. Loss of Asl in both humans and mice leads to reduced NO synthesis, owing to both decreased endogenous arginine synthesis and an impaired ability to use extracellular arginine for NO production. Administration of nitrite, which can be converted into NO in vivo, rescued the manifestations of NO deficiency in hypomorphic Asl mice, and a nitric oxide synthase (NOS)-independent NO donor restored NO-dependent vascular reactivity in humans with ASL deficiency. Mechanistic studies showed that ASL has a structural function in addition to its catalytic activity, by which it contributes to the formation of a multiprotein complex required for NO production. Our data demonstrate a previously unappreciated role for ASL in NOS function and NO homeostasis. Hence, ASL may serve as a target for manipulating NO production in experimental models, as well as for the treatment of NO-related diseases. 相似文献
86.
Margrete Solheim Mari C Brekke Lars G Snipen Rob JL Willems Ingolf F Nes Dag A Brede 《BMC microbiology》2011,11(1):3
Background
Enterococci rank among the leading causes of nosocomial infections. The failure to identify pathogen-specific genes in Enterococcus faecalis has led to a hypothesis where the virulence of different strains may be linked to strain-specific genes, and where the combined endeavor of the different gene-sets result in the ability to cause infection. Population structure studies by multilocus sequence typing have defined distinct clonal complexes (CC) of E. faecalis enriched in hospitalized patients (CC2, CC9, CC28 and CC40). 相似文献87.
Duijnisveld BJ Bigot A Beenakker KG Portilho DM Raz V van der Heide HJ Visser CP Chaouch S Mamchaoui K Westendorp RG Mouly V Butler-Browne GS Nelissen RG Maier AB 《Arthritis research & therapy》2011,13(6):R207-10
Introduction
Chronic inflammation is a profound systemic modification of the cellular microenvironment which could affect survival, repair and maintenance of muscle stem cells. The aim of this study was to define the role of chronic inflammation on the regenerative potential of satellite cells in human muscle.Methods
As a model for chronic inflammation, 11 patients suffering from rheumatoid arthritis (RA) were included together with 16 patients with osteoarthritis (OA) as controls. The mean age of both groups was 64 years, with more females in the RA group compared to the OA group. During elective knee replacement surgery, a muscle biopsy was taken from the distal musculus vastus medialis. Cell populations from four RA and eight OA patients were used for extensive phenotyping because these cell populations showed no spontaneous differentiation and myogenic purity greater than 75% after explantation.Results
After mononuclear cell explantation, myogenic purity, viability, proliferation index, number of colonies, myogenic colonies, growth speed, maximum number of population doublings and fusion index were not different between RA and OA patients. Furthermore, the expression of proteins involved in replicative and stress-induced premature senescence and apoptosis, including p16, p21, p53, hTERT and cleaved caspase-3, was not different between RA and OA patients. Mean telomere length was shorter in the RA group compared to the OA group.Conclusions
In the present study we found evidence that chronic inflammation in RA does not affect the in vitro regenerative potential of human satellite cells. Identification of mechanisms influencing muscle regeneration by modulation of its microenvironment may, therefore, be more appropriate. 相似文献88.
Bowman AB Kwakye GF Hernández EH Aschner M 《Journal of trace elements in medicine and biology》2011,25(4):191-203
Manganese (Mn) is an essential ubiquitous trace element that is required for normal growth, development and cellular homeostasis. Exposure to high Mn levels causes a clinical disease characterized by extrapyramidal symptom resembling idiopathic Parkinson's disease (IPD). The present review focuses on the role of various transporters in maintaining brain Mn homeostasis along with recent methodological advances in real-time measurements of intracellular Mn levels. We also provide an overview on the role for Mn in IPD, discussing the similarities (and differences) between manganism and IPD, and the relationship between α-synuclein and Mn-related protein aggregation, as well as mitochondrial dysfunction, Mn and PD. Additional sections of the review discuss the link between Mn and Huntington's disease (HD), with emphasis on huntingtin function and the potential role for altered Mn homeostasis and toxicity in HD. We conclude with a brief survey on the potential role of Mn in the etiologies of Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS) and prion disease. Where possible, we discuss the mechanistic commonalities inherent to Mn-induced neurotoxicity and neurodegenerative disorders. 相似文献
89.
Aschner JL Foster SL Kaplowitz M Zhang Y Zeng H Fike CD 《American journal of physiology. Lung cellular and molecular physiology》2007,292(6):L1515-L1525
Heat shock protein 90 (Hsp90) binding to endothelial nitric oxide synthase (eNOS) is an important step in eNOS activation. The conformational state of bound Hsp90 determines whether eNOS produces nitric oxide (NO) or superoxide (O(2)(*-)). We determined the effects of the Hsp90 antagonists geldanamycin (GA) and radicicol (RA) on basal and ACh-stimulated changes in vessel diameter, cGMP production, and Hsp90:eNOS coimmunoprecipitation in piglet resistance level pulmonary arteries (PRA). In perfused piglet lungs, we evaluated the effects of GA and RA on ACh-stimulated changes in pulmonary arterial pressure (Ppa) and perfusate accumulation of stable NO metabolites (NOx(-)). The effects of GA and RA on ACh-stimulated O(2)(*-) generation was investigated in cultured pulmonary microvascular endothelial cells (PMVEC) by dihydroethidine (DHE) oxidation and confocal microscopy. Hsp90 inhibition with GA or RA reduced ACh-mediated dilation, abolished the ACh-stimulated increase in cGMP, and reduced eNOS:Hsp90 coprecipitation. GA and RA also inhibited the ACh-mediated changes in Ppa and NOx(-) accumulation rates in perfused lungs. ACh increased the rate of DHE oxidation in PMVEC pretreated with GA and RA but not in untreated cells. The cell-permeable superoxide dismutase mimetic M40401 reversed GA-mediated inhibition of ACh-induced dilation in PRA. We conclude that Hsp90 is a modulator of eNOS activity and vascular reactivity in the newborn piglet pulmonary circulation. Uncoupling of eNOS with GA or RA inhibits ACh-mediated dilation by a mechanism that involves O(2)(*-) generation. 相似文献
90.
Jorit JL Meesters Ann Bremander Stefan Bergman Ingemar F Petersson Aleksandra Turkiewicz Martin Englund 《Arthritis research & therapy》2014,16(5)