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1.
Using the polymerase chain reaction (PCR) with Taq DNA polymerase, we have amplified a 2.4-kb fragment of genomic DNA containing the adenine phosphoribosyltransferase (APRT) gene from patients with APRT deficiency. Several clones from each patient were sequenced after subcloning the PCR product into M13mp18. Selected regions of the amplified fragment were also sequenced directly. This enabled us to distinguish PCR-induced errors from endogenous mutations and polymorphisms in each clone. 44 PCR errors were found in a total of 57,94 kb of DNA sequenced from 25 clones from 7 patients. All the errors were due to the PCR process and not to subcloning, as shown by sequence analysis of 5 APRT-positive clones isolated from a phage genomic library. 相似文献
2.
A new location for the human adenine phosphoribosyltransferase gene (APRT) distal to the haptoglobin (HP) and fra(16)(q23)(FRA16D) loci 总被引:8,自引:0,他引:8
A Fratini R N Simmers D F Callen V J Hyland J A Tischfield P J Stambrook G R Sutherland 《Cytogenetics and cell genetics》1986,43(1-2):10-13
The human adenine phosphoribosyltransferase gene (APRT) was mapped with respect to the haptoglobin gene (HP) and the fragile site at 16q23.2 (FRA16D). A subclone of APRT and a cDNA clone of HP were used for molecular hybridization to DNA from mouse-human hybrid cell lines containing specific chromosome 16 translocations. The APRT subclone was used for in situ hybridization to chromosomes expressing FRA16D. APRT was found to be distal to HP and FRA16D and was localized at 16q24, making the gene order cen-FRA16B-HP-FRA16D-APRT-qter. 相似文献
3.
Arpana Agrawal Sarah J. Brislin Kathleen K. Bucholz Danielle Dick Ronald P. Hart Emma C. Johnson Jacquelyn Meyers Jessica Salvatore Paul Slesinger COGA Collaborators Laura Almasy Tatiana Foroud Alison Goate Victor Hesselbrock John Kramer Samuel Kuperman Alison K. Merikangas John I. Nurnberger Jay Tischfield Howard J. Edenberg Bernice Porjesz 《Genes, Brain & Behavior》2023,22(5):e12864
4.
An Ustilago maydis ergosterol biosynthesis mutant (A14) which is partially blocked in sterol 14alpha-demethylase (P45014DM) activity is described. This mutant accumulated the abnormal 14alpha-methyl sterols, eburicol, 14alpha-methylfecosterol, and obtusifoliol, along with significant amounts of ergosterol. Although the A14 mutant grew nearly as well as the wild type, it was impaired in cell extension growth, which indicated a dysfunction in apical cell wall synthesis. The mutant was also found to be hypersensitive to the azole fungicides penconazole and tebuconazole. 相似文献
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Colony formation by variant Chinese hamster cells highly resistant to adenine analogs and deficient in adenine phosphoribosyltransferase (APRT) activity was measured after co-cultivation with APRT+, CHO-K1 cells in medium containing one of three different adenine analogs. Depending upon the density of APRT+ cells and the specific adenine analog, large differences in the recovery of APRT? colonies were observed. The particular adenine analog and APRT+ cell density were more significant factors in the recovery of APRT? colonies than the concentration of the analog or the level of APRT activity. The number of wild-type cells (CHO-K1) required to inhibit formation of APRT? colonies by 50% (mean lethal density; MLD50) with 65 μg/ml 8-aza-adenine (AzA) as the selective drug was 8.0 × 105 cells/100 mm dish (1.5 × 104/cm2). With 100 μg/ml 2,6-diaminopurine (DAP) the MLD50 for CHO-K1 was 4.0 × 105 cells/100 mm dish (7.3 × 103/cm2). The MLD50 for CHO-K1 when the DAP concentration was decreased to 50 μg/ml was only slightly higher, 5 × 105 cells/100 mm dish (9.1 × 103/cm2). The most toxic effect was observed with 2-fluoroadenine (FA). The MLD50 for CHO-K1 in 2 μg/ml FA was 4.5 × 104 cells/100 mm dish (8.2 × 102/cm2), a cell density which permits minimal direct contact between APRT+ and APRT? cells. The toxic effects of FA on individually resistant, APRT? cells were found to be mediated by metabolites released into the medium by dying APRT+ cells. This metabolite toxicity to APRT? cells was also demonstrated in mixtures with cells having only 8% of wild-type APRT activity. The MLD50 for these APRT+ (8%) cells in 2 μg/ml FA was 7.5 × 104 cells/100 dish (1.4 × 103/cm2), a small difference from the MLD50 for cells with wild-type levels of APRT activity. The differences in the recovery of APRT? colonies from mixtures with APRT+ cells in these three adenine analogs are critical to the design of procedures for the selection of APRT? cells from populations of APRT+ cells and emphasize the importance of establishing the parameters of metabolic cooperation, not only in terms of cell density but also with regard to the particular selective agent, in any experiment designed to determine precise mutation rates or to test putative mutagens upon mammalian cells in culture. 相似文献
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JA Kiernan 《Biotechnic & histochemistry》2013,88(5-6):203-210
Hexazonium pararosaniline is a valuable reagent that has been used in enzyme activity histochemistry for 50 years. It is an aqueous solution containing the tris-diazonium ion derived from pararosaniline, an aminotriarylmethane dye, and it contains an excess of nitrous acid that was not consumed in the diazotization reaction. Other investigators have found that immersion for 2 min in an acidic (pH 3.5) 0.0015 M hexazonium pararosaniline solution can protect cryostat sections of unfixed animal tissues from the deleterious effects of aqueous reagents such as buffered solutions used in immunohistochemistry, while preserving specific affinities for antibodies. In the present investigation hexazonium pararosaniline protected lymphoid tissue and striated muscle against the damaging effects of water or saline. The same protection was conferred on unfixed sections treated with dilute nitrous or hydrochloric acid in concentrations similar to those in hexazonium pararosaniline solutions. Model tissues (solutions, gels or films containing gelatin and/or bovine albumin) responded predictably to well known cross-linking (formaldehyde) or coagulant (mercuric chloride) fixatives. Hexazonium pararosaniline solutions prevented the dissolution of protein gels in water only after 9 or more days of contact, during which time considerable swelling occurred. It is concluded that there is no evidence for a “fixative” action of hexazonium pararosaniline. The protective effect on frozen sections of unfixed tissue is attributable probably to the low pH of the solution. 相似文献
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Water hyacinth Eichhornia crassipes is considered the most damaging aquatic weed in the world. However, few studies have quantified the impact of this weed economically and ecologically, and even fewer studies have quantified the benefits of its control. This paper focuses on water loss saving as the benefit derived from biological control of this plant between 1990 and 2013 at New Year’s Dam, Alicedale, Eastern Cape, South Africa. Estimates of water loss due to evapotranspiration from water hyacinth vary significantly; therefore, the study used three different rates, high, medium and low. A conservative raw agriculture value of R 0.26 per m3 was used to calculate the benefits derived by the water saved. The present benefit and cost values were determined using 10% and 5% discount rates. The benefit/cost ratio at the low evapotranspiration rate was less than one, implying that biological control was not economically viable but, at the higher evapotranspiration rates, the return justified the costs of biological control. However, at the marginal value product of water, the inclusion of the costs of damage to infrastructure, or the adverse effects of water hyacinth on biodiversity, would justify the use of biological control, even at the low transpiration rate. 相似文献