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61.
Tyrosyl-DNA phosphodiesterase 1 (Tdp1) catalyzes the hydrolysis of the phosphodiester linkage between the DNA 3' phosphate and a tyrosine residue as well as a variety of other DNA 3' damaged termini. Recently we have shown that Tdp1 can liberate the 3' DNA phosphate termini from apurinic/apyrimidinic (AP) sites. Here, we found that Tdp1 is more active in the cleavage of the AP sites inside bubble-DNA structure in comparison to ssDNA containing AP site. Furthermore, Tdp1 hydrolyzes AP sites opposite to bulky fluorescein adduct faster than AP sites located in dsDNA. Whilst the Tdp1 H493R (SCAN1) and H263A mutants retain the ability to bind an AP site-containing DNA, both mutants do not reveal endonuclease activity, further suggesting the specificity of the AP cleavage activity. We suggest that this Tdp1 activity can contribute to the repair of AP sites particularly in DNA structures containing ssDNA region or AP sites in the context of clustered DNA lesions. 相似文献
62.
Michelle L Cloutier A Toutant J Shkreta L Thibault P Durand M Garneau D Gendron D Lapointe E Couture S Le Hir H Klinck R Elela SA Prinos P Chabot B 《Molecular and cellular biology》2012,32(5):954-967
Several apoptotic regulators, including Bcl-x, are alternatively spliced to produce isoforms with opposite functions. We have used an RNA interference strategy to map the regulatory landscape controlling the expression of the Bcl-x splice variants in human cells. Depleting proteins known as core (Y14 and eIF4A3) or auxiliary (RNPS1, Acinus, and SAP18) components of the exon junction complex (EJC) improved the production of the proapoptotic Bcl-x(S) splice variant. This effect was not seen when we depleted EJC proteins that typically participate in mRNA export (UAP56, Aly/Ref, and TAP) or that associate with the EJC to enforce nonsense-mediated RNA decay (MNL51, Upf1, Upf2, and Upf3b). Core and auxiliary EJC components modulated Bcl-x splicing through different cis-acting elements, further suggesting that this activity is distinct from the established EJC function. In support of a direct role in splicing control, recombinant eIF4A3, Y14, and Magoh proteins associated preferentially with the endogenous Bcl-x pre-mRNA, interacted with a model Bcl-x pre-mRNA in early splicing complexes, and specifically shifted Bcl-x alternative splicing in nuclear extracts. Finally, the depletion of Y14, eIF4A3, RNPS1, SAP18, and Acinus also encouraged the production of other proapoptotic splice variants, suggesting that EJC-associated components are important regulators of apoptosis acting at the alternative splicing level. 相似文献
63.
Kersh GJ Lambourn DM Raverty SA Fitzpatrick KA Self JS Akmajian AM Jeffries SJ Huggins J Drew CP Zaki SR Massung RF 《Journal of wildlife diseases》2012,48(1):201-206
Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii. Humans are commonly exposed via inhalation of aerosolized bacteria derived from the waste products of domesticated sheep and goats, and particularly from products generated during parturition. However, many other species can be infected with C. burnetii, and the host range and full zoonotic potential of C. burnetii is unknown. Two cases of C. burnetii infection in marine mammal placenta have been reported, but it is not known if this infection is common in marine mammals. To address this issue, placenta samples were collected from Pacific harbor seals (Phoca vitulina richardsi), harbor porpoises (Phocoena phocoena), and Steller sea lions (Eumetopias jubatus). Coxiella burnetii was detected by polymerase chain reaction (PCR) in the placentas of Pacific harbor seals (17/27), harbor porpoises (2/6), and Steller sea lions (1/2) collected in the Pacific Northwest. A serosurvey of 215 Pacific harbor seals sampled in inland and outer coastal areas of the Pacific Northwest showed that 34.0% (73/215) had antibodies against either Phase 1 or Phase 2 C. burnetii. These results suggest that C. burnetii infection is common among marine mammals in this region. 相似文献
64.
NF Gallardo-Romero CP Drew SL Weiss MG Metcalfe YJ Nakazawa SK Smith GL Emerson CL Hutson JS Salzer JH Bartlett VA Olson CJ Clemmons WB Davidson SR Zaki KL Karem IK Damon DS Carroll 《PloS one》2012,7(8):e43881
Volepox virus (VPXV) was first isolated in 1985 from a hind foot scab of an otherwise healthy California vole (Microtus californicus). Subsequent surveys in San Mateo County, CA, revealed serological evidence suggesting that VPXV is endemic to this area, and a second viral isolate from a Pinyon mouse (Peromyscus truei) was collected in 1988. Since then, few studies have been conducted regarding the ecology, pathology, and pathogenicity of VPXV, and its prevalence and role as a potential zoonotic agent remain unknown. To increase our understanding of VPXV disease progression, we challenged 24 California mice (Peromyscus californicus) intranasally with 1.6×10(3) PFU of purified VPXV. By day five post infection (pi) we observed decreased activity level, conjunctivitis, ruffled hair, skin lesions, facial edema, and crusty noses. A mortality rate of 54% was noted by day eight pi. In addition, internal organ necrosis and hemorrhages were observed during necropsy of deceased or euthanized animals. Viral loads in tissues (brain, gonad, kidney, liver, lung, spleen, submandibular lymph node, and adrenal gland), bodily secretions (saliva, and tears), and excretions (urine, and/or feces) were evaluated and compared using real time-PCR and tissue culture. Viral loads measured as high as 2×10(9) PFU/mL in some organs. Our results suggest that VPXV can cause extreme morbidity and mortality within rodent populations sympatric with the known VPXV reservoirs. 相似文献
65.
Dey S Maiti AK Hegde ML Hegde PM Boldogh I Sarkar PS Abdel-Rahman SZ Sarker AH Hang B Xie J Tomkinson AE Zhou M Shen B Wang G Wu C Yu D Lin D Cardenas V Hazra TK 《DNA Repair》2012,11(6):570-578
Human NEIL2, one of five oxidized base-specific DNA glycosylases, is unique in preferentially repairing oxidative damage in transcribed genes. Here we show that depletion of NEIL2 causes a 6-7-fold increase in spontaneous mutation frequency in the HPRT gene of the V79 Chinese hamster lung cell line. This prompted us to screen for NEIL2 variants in lung cancer patients' genomic DNA. We identified several polymorphic variants, among which R103Q and R257L were frequently observed in lung cancer patients. We then characterized these variants biochemically, and observed a modest decrease in DNA glycosylase activity relative to the wild type (WT) only with the R257L mutant protein. However, in reconstituted repair assays containing WT NEIL2 or its R257L and R103Q variants together with other DNA base excision repair (BER) proteins (PNKP, Polβ, Lig IIIα and XRCC1) or using NEIL2-FLAG immunocomplexes, an ~5-fold decrease in repair was observed with the R257L variant compared to WT or R103Q NEIL2, apparently due to the R257L mutant's lower affinity for other repair proteins, particularly Polβ. Notably, increased endogenous DNA damage was observed in NEIL2 variant (R257L)-expressing cells relative to WT cells. Taken together, our results suggest that the decreased DNA repair capacity of the R257L variant can induce mutations that lead to lung cancer development. 相似文献
66.
Brian R. Amman Serena A. Carroll Zachary D. Reed Tara K. Sealy Stephen Balinandi Robert Swanepoel Alan Kemp Bobbie Rae Erickson James A. Comer Shelley Campbell Deborah L. Cannon Marina L. Khristova Patrick Atimnedi Christopher D. Paddock Rebekah J. Kent Crockett Timothy D. Flietstra Kelly L. Warfield Robert Unfer Edward Katongole-Mbidde Robert Downing Jordan W. Tappero Sherif R. Zaki Pierre E. Rollin Thomas G. Ksiazek Stuart T. Nichol Jonathan S. Towner 《PLoS pathogens》2012,8(10)
Marburg virus (family Filoviridae) causes sporadic outbreaks of severe hemorrhagic disease in sub-Saharan Africa. Bats have been implicated as likely natural reservoir hosts based most recently on an investigation of cases among miners infected in 2007 at the Kitaka mine, Uganda, which contained a large population of Marburg virus-infected Rousettus aegyptiacus fruit bats. Described here is an ecologic investigation of Python Cave, Uganda, where an American and a Dutch tourist acquired Marburg virus infection in December 2007 and July 2008. More than 40,000 R. aegyptiacus were found in the cave and were the sole bat species present. Between August 2008 and November 2009, 1,622 bats were captured and tested for Marburg virus. Q-RT-PCR analysis of bat liver/spleen tissues indicated ∼2.5% of the bats were actively infected, seven of which yielded Marburg virus isolates. Moreover, Q-RT-PCR-positive lung, kidney, colon and reproductive tissues were found, consistent with potential for oral, urine, fecal or sexual transmission. The combined data for R. aegyptiacus tested from Python Cave and Kitaka mine indicate low level horizontal transmission throughout the year. However, Q-RT-PCR data show distinct pulses of virus infection in older juvenile bats (∼six months of age) that temporarily coincide with the peak twice-yearly birthing seasons. Retrospective analysis of historical human infections suspected to have been the result of discrete spillover events directly from nature found 83% (54/65) events occurred during these seasonal pulses in virus circulation, perhaps demonstrating periods of increased risk of human infection. The discovery of two tags at Python Cave from bats marked at Kitaka mine, together with the close genetic linkages evident between viruses detected in geographically distant locations, are consistent with R. aegyptiacus bats existing as a large meta-population with associated virus circulation over broad geographic ranges. These findings provide a basis for developing Marburg hemorrhagic fever risk reduction strategies. 相似文献
67.
Wafaa M. Ezzat Shadia Ragab Nagwa Abdallah Ismail Yasser A. Elhosary Abeer M. Nour Eldin Abd ElBaky Hebatallah Farouk Inas Abdel Rasheed 《Journal of Genetic Engineering and Biotechnology》2012,10(2):221-227
Non-alcoholic fatty liver disease (NAFLD) is a condition defined by significant lipid accumulation (5–10%) in hepatic tissue in the absence of significant chronic alcohol consumption. We aim to detect frequency of fatty liver among overweight/obese adults and children and associated clinical; anthropological measures; biochemical; genetic and imaging studies. Eighty three consecutive adults and 72 children included in the study. All patients underwent clinical measurements of height, body weight, body mass index (BMI), waist and hip circumference. Biochemical investigations were done to all subjects including liver function tests; lipid profile; fasting blood glucose; insulin resistance (IR); high sensitivity C reactive protein (hs-CRP); adiponectin and genotyping of adiponectin genes. Abdominal ultrasonography was done to search for fatty liver; to measure subcutaneous fat thickness (SFT) and visceral fat thickness (VFT). Fatty liver was detected in 47 (65.3%) children and in 52 (62.7%) adults. Correlation analysis in both groups revealed that enlarged liver was highly positively correlated to age; BMI, systolic blood pressure (SBP), diastolic blood pressure (DBP); waist circumference; hip circumference, subcutaneous fat thickness (SFT) and Visceral fat thickness (VFT), alanine aminotransferase (ALT), aspartate aminotransferase/alanine aminotransferase (AST/ALT). In addition in adults to fasting blood glucose, cholesterol, triglycerides (TG), low density lipoprotein (LDL), IR and hs-CRP. Homozygous T adiponectin genotype at position +276 was significantly increased among children with enlarged liver size and hs-CRP. NAFLD affects a substantial portion of adults and children; it is associated with the metabolic syndrome. 相似文献
68.
69.
Chabot B Elela SA Zhuo D 《BioEssays : news and reviews in molecular, cellular and developmental biology》2008,30(11-12):1256; author reply 1257-1256; author reply 1258
70.