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91.
Oxidative stress and free radical production have been implicated in Alzheimer's disease, where low levels of the antioxidant vitamin C (ascorbate) have been shown to be associated with the disease. In this study, neuroblastoma SH-SY5Y cells were treated with hydrogen peroxide in the presence of ascorbate in order to elucidate the mechanism(s) of protection against oxidative stress afforded by ascorbate. Protein oxidation, glutathione levels, cell viability and the effects on the proteome and its oxidized counterpart were monitored. SH-SY5Y cells treated with ascorbate prior to co-incubation with peroxide showed increased viability in comparison to cells treated with peroxide alone. This dual treatment also caused an increase in protein carbonyl content and a decrease in glutathione levels within the cells. Proteins, extracted from SH-SY5Y cells that were treated with either ascorbate or peroxide alone or with ascorbate prior to peroxide, were separated by two-dimensional gel electrophoresis and analyzed for oxidation. Co-incubation for 24 hours decreased the number of oxidised proteins (e.g. acyl CoA oxidase 3) and induced brain derived neurotrophic factor (BDNF) expression. Enhanced expression of BDNF may contribute to the protective effects of ascorbate against oxidative stress in neuronal cells. 相似文献
92.
Combs TP Nagajyothi Mukherjee S de Almeida CJ Jelicks LA Schubert W Lin Y Jayabalan DS Zhao D Braunstein VL Landskroner-Eiger S Cordero A Factor SM Weiss LM Lisanti MP Tanowitz HB Scherer PE 《The Journal of biological chemistry》2005,280(25):24085-24094
Adipose tissue plays an active role in normal metabolic homeostasis as well as in the development of human disease. Beyond its obvious role as a depot for triglycerides, adipose tissue controls energy expenditure through secretion of several factors. Little attention has been given to the role of adipocytes in the pathogenesis of Chagas disease and the associated metabolic alterations. Our previous studies have indicated that hyperglycemia significantly increases parasitemia and mortality in mice infected with Trypanosoma cruzi. We determined the consequences of adipocyte infection in vitro and in vivo. Cultured 3T3-L1 adipocytes can be infected with high efficiency. Electron micrographs of infected cells revealed a large number of intracellular parasites that cluster around lipid droplets. Furthermore, infected adipocytes exhibited changes in expression levels of a number of different adipocyte-specific or adipocyte-enriched proteins. The adipocyte is therefore an important target cell during acute Chagas disease. Infection of adipocytes by T. cruzi profoundly influences the pattern of adipokines. During chronic infection, adipocytes may represent an important long-term reservoir for parasites from which relapse of infection can occur. We have demonstrated that acute infection has a unique metabolic profile with a high degree of local inflammation in adipose tissue, hypoadiponectinemia, hypoglycemia, and hypoinsulinemia but with relatively normal glucose disposal during an oral glucose tolerance test. 相似文献
93.
Rusling DA Le Strat L Powers VE Broughton-Head VJ Booth J Lack O Brown T Fox KR 《FEBS letters》2005,579(29):6616-6620
We have used DNase I footprinting to examine DNA triple helix formation at a 12 base pair oligopurine.oligopyrimidine sequence, using oligonucleotides that contain combinations of 2'-aminoethoxy-5-(3-aminoprop-1-ynyl)uridine (bis-amino-U, BAU) and 3-methyl-2-aminopyridine (MeP) in place of T and C, respectively. This combination acts cooperatively to enable high affinity triple helix formation at physiological pH. The affinity depends on the number of substitutions and their arrangement; oligonucleotides in which these analogues are evenly distributed throughout the third strand bind much better than those in which they are clustered together. 相似文献
94.
The protein tyrosine phosphatase Src homology 2 domain-containing phosphatase 1 (SHP-1) has previously been shown to be a negative regulator of signaling mediated via the TCR. A growing body of evidence indicates that the regulated localization of proteins within certain membrane subdomains, referred to as lipid rafts, is important for the successful transduction of signaling events downstream of the TCR. However, considerably less is known about the localization of negative regulators during these lipid raft-dependent signaling events. In this study we have investigated the subcellular localization of SHP-1 and its role in regulation of TCR-mediated signaling. Our studies demonstrate that in a murine T cell hybridoma as well as in primary murine thymocytes, a fraction of SHP-1 localizes to the lipid rafts, both basally and after TCR stimulation. Interestingly, although SHP-1 localized in the nonraft fractions is tyrosine phosphorylated, the SHP-1 isolated from the lipid rafts lacks the TCR-induced tyrosine phosphorylation, suggesting physical and/or functional differences between these two subpopulations. We identify a requirement for the C-terminal residues of SHP-1 in optimal localization to the lipid rafts. Although expression of SHP-1 that localizes to lipid rafts potently inhibits TCR-mediated early signaling events and IL-2 production, the expression of lipid raft-excluded SHP-1 mutants fails to elicit any of the inhibitory effects. Taken together these studies reveal a key role for lipid raft localization of SHP-1 in mediating the inhibitory effects on T cell signaling events. 相似文献
95.
Circulation of type 1 vaccine-derived poliovirus in the Philippines in 2001 总被引:14,自引:0,他引:14 下载免费PDF全文
Shimizu H Thorley B Paladin FJ Brussen KA Stambos V Yuen L Utama A Tano Y Arita M Yoshida H Yoneyama T Benegas A Roesel S Pallansch M Kew O Miyamura T 《Journal of virology》2004,78(24):13512-13521
In 2001, highly evolved type 1 circulating vaccine-derived poliovirus (cVDPV) was isolated from three acute flaccid paralysis patients and one contact from three separate communities in the Philippines. Complete genomic sequencing of these four cVDPV isolates revealed that the capsid region was derived from the Sabin 1 vaccine strain but most of the noncapsid region was derived from an unidentified enterovirus unrelated to the oral poliovirus vaccine (OPV) strains. The sequences of the cVDPV isolates were closely related to each other, and the isolates had a common recombination site. Most of the genetic and biological properties of the cVDPV isolates were indistinguishable from those of wild polioviruses. However, the most recently identified cVDPV isolate from a healthy contact retained the temperature sensitivity and partial attenuation phenotypes. The sequence relationships among the isolates and Sabin 1 suggested that cVDPV originated from an OPV dose given in 1998 to 1999 and that cVDPV circulated along a narrow chain of transmission. Type 1 cVDPV was last detected in the Philippines in September 2001, and population immunity to polio was raised by extensive OPV campaigns in late 2001 and early 2002. 相似文献
96.
Molecular phylogenetic analyses indicate a wide and ancient radiation of African hepatitis delta virus, suggesting a deltavirus genus of at least seven major clades 总被引:3,自引:0,他引:3 下载免费PDF全文
Radjef N Gordien E Ivaniushina V Gault E Anaïs P Drugan T Trinchet JC Roulot D Tamby M Milinkovitch MC Dény P 《Journal of virology》2004,78(5):2537-2544
Hepatitis D virus (HDV) is a satellite of hepatitis B virus (HBV) for transmission and propagation and infects nearly 20 million people worldwide. The HDV genome is a compact circular single-stranded RNA genome with extensive intramolecular complementarity. Despite its different epidemiological and pathological patterns, the variability and geographical distribution of HDV are limited to three genotypes and two subtypes that have been characterized to date. Phylogenetic reconstructions based on the delta antigen gene and full-length genome sequence data show an extensive and probably ancient radiation of African lineages, suggesting that the genetic variability of HDV is much more complex than was previously thought, with evidence of additional clades. These results relate the geographic distribution of HDV more closely to the genetic variability of its helper HBV. 相似文献
97.
Assessment-of-Dominant-Damage (ADD) experiments explored induction by proven specific-locus mutagens of dominant mutations that cause skeletal anomalies, cataracts, and stunted growth in offspring of mutagenized male mice. The data set reported here includes 6134 offspring. Mutagenic treatments included 600 R (i.e., approximately 6 Gy) of X-rays delivered in about 7 min, 600 R of gamma rays delivered over about 110 days, and four weekly intraperitoneal (i.p.) injections of 77.5 mg/kg of ethylnitrosourea (ENU). The results reported in this paper are restricted to mutations induced in stem-cell spermatogonia and to the 34 more common skeletal anomalies (i.e., those found in 0.5% or more of the control offspring). Mutation induction was demonstrated for eight anomalies in the acute X-ray experiment and for 17 anomalies (including those same eight anomalies) in the ENU experiment. In spite of the surprisingly high mutation rates found for these treatments, there was no hint of any induction of such dominant mutations by 600 R of chronic gamma radiation. Our results suggest that several anomalies related to variation in the sacralization pattern may be particularly useful for revealing induction of dominant mutations. 相似文献
98.
Li H Broughton-Head VJ Peng G Powers VE Ovens MJ Fox KR Brown T 《Bioconjugate chemistry》2006,17(6):1561-1567
A method has been developed to attach 4'-(hydroxymethyl)-4,5',8-trimethylpsoralen to the 5 position of thymine bases during solid-phase oligonucleotide synthesis. UV irradiation of triplex-forming oligonucleotides (TFOs) containing internally attached psoralens produces photoadducts at TpA steps within target duplexes, thus relaxing the constraints on selection of psoralen target sequences. Photoreaction of TFOs containing two psoralens, located at the 5'- and 3'-ends, has been used to create double-strand cross-links (triplex staples) at both termini of the TFO. Such complexes have no free single-stranded ends. TFOs containing 4'-(hydroxymethyl)-4,5',8-trimethylpsoralen, 3-methyl-2-aminopyridine, and 5-(3-aminoprop-2-ynyl)deoxyuridine formed photoadducts with target duplexes under near-physiological conditions. 相似文献
99.
Jonathan H. Epstein Jeffrey McKee Phil Shaw Vicki Hicks Gino Micalizzi Peter Daszak A. Marm Kilpatrick Gretchen Kaufman 《EcoHealth》2006,3(4):290-298
Over the last 20 years, Australian white ibis populations (Threskiornis molucca) have expanded into urban areas, leading to increased contact between ibis, domestic animals, and humans. This has led to
concern that ibis may transmit pathogens that threaten public health or food production. Here we report results from a study
of ibis viral serology and bacterial culture that indicate that ibis are hosts of zoonotic and livestock pathogens such as
Salmonella spp., Newcastle disease virus, avian influenza virus, and flaviviruses in Australia. We also performed a behavioral study
to measure contact rates among ibis, people, and livestock that determine the potential for disease transmission. 相似文献
100.