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排序方式: 共有105条查询结果,搜索用时 15 毫秒
1.
A fetus with a 46,XX,r(17) karyotype identified initially by amniocentesis and confirmed by banding studies is described. No significant phenotypic abnormalities were identified despite isolation of the ring chromosome from multiple fetal tissues. This paucity of abnormal features of gross development is consistent with findings in 3 previously reported patients with ring 17 chromosomes. 相似文献
2.
H M Shields S T Yedlin F A Bair C L Goodwin D H Alpers 《The American journal of anatomy》1979,155(3):375-389
Ileum from rats 4, 9, 11, 12, and 15 days old can best be maintained for 24 hours in a system using Hanks' Balanced Salt Solution without fetal calf serum, at 25 degrees C and 21% O2. Suckling rat duodenum and jejunum were difficult to maintain well for 24 hours in this system or a variety of other systems that were tried. A temperature of 37 degrees C hastened deterioration of duodenum, jejunum or ileum. With ileum, 3H-thymidine and 14C-leucine were increasingly incorporated into DNA and protein over the 24-hour period. Light microscopy, as well as scanning and transmission electron microscopy, showed very good preservation of the ileum after 24 hours. The addition to the medium of hydrocortisone, 1 micron, and thyroxine, 0.01 micron, alone or in combination, did not change DNA or protein synthesis, or morphology, possibly because of the relatively short (24 hour) time period. Our organ culture system emphasizes the differences between suckling rat ileum and the rest of the intestine, and provides a new tool for evaluating, over a 24-hour period, the developing rat small intestine. 相似文献
3.
In Prince Edward Island, Canada, widespread intensive potato production has contributed to elevated nitrate concentrations in groundwater and streams, and eutrophic or anoxic conditions occur regularly in several estuarine systems. In this research, the stable isotopes of nitrogen and oxygen in nitrate in intertidal groundwater discharge and stream water were used, in conjunction with water quality and quantity data and land use information, to better understand the characteristics of nitrate delivered to two small estuaries with contrasting land use in their contributory catchments. Most of the water samples collected during the two-year study had isotopic signatures that fell in the range expected for nitrate derived from ammonium-based fertilizers (26.5 % of the samples) or in the overlapping range formed between ammonium-based fertilizers and nitrate derived from soil (64 % of the samples). Overall, isotopic signatures spanned over relatively narrow ranges, and correlations with other water quality parameters, or catchment characteristics, were weak. Nitrate in groundwater discharge and surface water in the Trout River catchment exhibited significantly different isotopic signatures only for the nitrogen isotope, while in the McIntyre Creek catchment groundwater discharge and surface water had similar isotopic signatures. When the isotopic results for the waters from the two catchments were compared, the surface waters were found to be similar, while the isotopic signatures of nitrate in groundwater were distinct only for the nitrogen isotope. Denitrification in the two study catchments was not evident based on the isotopic results for nitrate; however, in the case of the Trout River catchment, where a small freshwater pond exists, an average nitrate load reduction of 14 % was inferred based on a comparison of nitrate loads entering and leaving the pond. Overall, it appears that natural attenuation processes, occurring either in the streams or groundwater flow systems, do not significantly reduce nitrate loading to these estuaries. 相似文献
4.
Semi-supervised methods to predict patient survival from gene expression data 总被引:1,自引:0,他引:1
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An important goal of DNA microarray research is to develop tools to diagnose cancer more accurately based on the genetic profile of a tumor. There are several existing techniques in the literature for performing this type of diagnosis. Unfortunately, most of these techniques assume that different subtypes of cancer are already known to exist. Their utility is limited when such subtypes have not been previously identified. Although methods for identifying such subtypes exist, these methods do not work well for all datasets. It would be desirable to develop a procedure to find such subtypes that is applicable in a wide variety of circumstances. Even if no information is known about possible subtypes of a certain form of cancer, clinical information about the patients, such as their survival time, is often available. In this study, we develop some procedures that utilize both the gene expression data and the clinical data to identify subtypes of cancer and use this knowledge to diagnose future patients. These procedures were successfully applied to several publicly available datasets. We present diagnostic procedures that accurately predict the survival of future patients based on the gene expression profile and survival times of previous patients. This has the potential to be a powerful tool for diagnosing and treating cancer. 相似文献
5.
Proteomics-based target identification: bengamides as a new class of methionine aminopeptidase inhibitors 总被引:2,自引:0,他引:2
Towbin H Bair KW DeCaprio JA Eck MJ Kim S Kinder FR Morollo A Mueller DR Schindler P Song HK van Oostrum J Versace RW Voshol H Wood J Zabludoff S Phillips PE 《The Journal of biological chemistry》2003,278(52):52964-52971
LAF389 is a synthetic analogue of bengamides, a class of marine natural products that produce inhibitory effects on tumor growth in vitro and in vivo. A proteomics-based approach has been used to identify signaling pathways affected by bengamides. LAF389 treatment of cells resulted in altered mobility of a subset of proteins on two-dimensional gel electrophoresis. Detailed analysis of one of the proteins, 14-3-3gamma, showed that bengamide treatment resulted in retention of the amino-terminal methionine, suggesting that bengamides directly or indirectly inhibited methionine aminopeptidases (MetAps). Both known MetAps are inhibited by LAF389. Short interfering RNA suppression of MetAp2 also altered amino-terminal processing of 14-3-3gamma. A high resolution structure of human MetAp2 co-crystallized with a bengamide shows that the compound binds in a manner that mimics peptide substrates. Additionally, the structure reveals that three key hydroxyl groups on the inhibitor coordinate the di-cobalt center in the enzyme active site. 相似文献
6.
Steven G. Smith Kaatje Smits Simone A. Joosten Krista E. van Meijgaarden Iman Satti Helen A. Fletcher Nadia Caccamo Francesco Dieli Francoise Mascart Helen McShane Hazel M. Dockrell Tom H. M. Ottenhoff TBVI TB Biomarker Working Group 《PloS one》2015,10(9)
Intracellular cytokine staining combined with flow cytometry is one of a number of assays designed to assess T-cell immune responses. It has the specific advantage of enabling the simultaneous assessment of multiple phenotypic, differentiation and functional parameters pertaining to responding T-cells, most notably, the expression of multiple effector cytokines. These attributes make the technique particularly suitable for the assessment of T-cell immune responses induced by novel tuberculosis vaccines in clinical trials. However, depending upon the particular nature of a given vaccine and trial setting, there are approaches that may be taken at different stages of the assay that are more suitable than other alternatives. In this paper, the Tuberculosis Vaccine Initiative (TBVI) TB Biomarker Working group reports on efforts to assess the conditions that will determine when particular assay approaches should be employed. We have found that choices relating to the use of fresh whole blood or peripheral blood mononuclear cells (PBMC) and frozen PBMC; use of serum-containing or serum-free medium; length of stimulation period and use of co-stimulatory antibodies can all affect the sensitivity of intracellular cytokine assays. In the case of sample material, frozen PBMC, despite some loss of sensitivity, may be more advantageous for batch analysis. We also recommend that for multi-site studies, common antibody panels, gating strategies and analysis approaches should be employed for better comparability. 相似文献
7.
The Escherichia coli CT596 prophage exclusion genes gmrS and gmrD were found to encode a novel type IV modification-dependent restriction nuclease that targets and digests glucosylated (glc)-hydroxymethylcytosine (HMC) DNAs. The protein products GmrS (36 kDa) and GmrD (27 kDa) were purified and found to be inactive separately, but together degraded several different glc-HMC modified DNAs (T4, T2 and T6). The GMR enzyme is able to degrade both alpha-glucosy-HMC T4 DNA and beta-glucosyl-HMC T4 DNA, whereas no activity was observed against non-modified DNAs including unmodified T4 cytosine (C) DNA or non-glucosylated T4 HMC DNA. Enzyme activity requires NTP, favors UTP, is stimulated by calcium, and initially produces 4 kb DNA fragments that are further degraded to low molecular mass products. The enzyme is inhibited by the T4 phage internal protein I* (IPI*) to which it was found to bind. Overall activities of the purified GmrSD enzyme are in good agreement with the properties of the cloned gmr genes in vivo and suggest a restriction enzyme specific for sugar modified HMC DNAs. IPI* thus represents a third generation bacteriophage defense against restriction nucleases of the Gmr type. 相似文献
8.
Wu IC Wu DC Hsu PI Lu CY Yu FJ Wang TE Chang WH Chen JJ Kuo FC Wu JY Wang WM Bair MJ 《Helicobacter》2007,12(6):633-637
BACKGROUND: Different kinds of proton pump inhibitor-based triple therapies could result in different Helicobacter pylori eradication rates. AIM: The aims of this study were to compare the efficacy and safety of rabeprazole- and esomeprazole-based triple therapy in primary treatment of H. pylori infection in Taiwan. PATIENTS AND METHODS: From June 2005 to March 2007, 420 H. pylori-infected patients were randomly assigned to receive a 7-day eradication therapy with either esomeprazole 40 mg daily (EAC group, n = 209) or rabeprazole 20 mg b.i.d. (RAC group, n = 211) in combination with amoxicillin 1 g b.i.d. and clarithromycin 500 mg b.i.d.. Follow-up endoscopy with biopsy was done 12-16 weeks after completion of eradication therapy. Those who refused endoscopic exams underwent (13)C-urea breath test to assess the treatment response. RESULTS: Intention-to-treat analysis revealed that the eradication rate was 89.4% in the EAC group and 90.5% in RAC groups (p-value = .72). All of the subjects returned for assessment of compliance (100% in EAC group vs. 99.5% in RAC group, p-value = .32) and adverse events (3.83% in EAC group vs. 6.16% in RAC group, p-value = .27). Sixty (28.7%) and 37 (17.6%) patients in EAC and RAC group, respectively, refused endoscopy and underwent a (13)C-urea breath test to determine the treatment effect. CONCLUSION: In conclusion, rabeprazole- and esomeprazole-based primary therapies for H. pylori infection are comparable in efficacy and safety. 相似文献
9.
10.
Understanding protein-protein interactions that occur between ACP and KS domains of polyketide synthases and fatty acid synthases is critical to improving the scope and efficiency of combinatorial biosynthesis efforts aimed at producing non-natural polyketides. Here, we report a facile strategy for rapidly reporting such ACP-KS interactions based on the incorporation of an amino acid with photocrosslinking functionality. Crucially, this photocrosslinking strategy can be applied to any polyketide or fatty acid synthase regardless of substrate specificity, and can be adapted to a high-throughput format for directed evolution studies. 相似文献