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31.
A metal free and highly stereoselective procedure for the synthesis of 2,3-unsaturated-C-glycosides has been developed between glycals and unactivated aryl acetylenes in the presence of TMSOTf through a triflated C-vinyl glycosides intermediate. The flexibility of the procedure was tested by a wide variety of glycals and unactivated aryl acetylenes (20 examples). The corresponding alkynyl C-glycosides were obtained in good yields with completely α-selectivity in a short time (<25 min). And a plausible mechanism for the synthesis of alkynyl C-glycosides was depicted.  相似文献   
32.
Hierarchically porous nitrogen‐doped carbon (HPC)/polyaniline (PANI) nanowire arrays nanocomposites are synthesized by a facile in situ polymerization. 3D interconnected honeycomb‐like HPC was prepared by a cost‐effective route via one‐step carbonization using urea and alkali‐treated wheat flour as carbon precursor with a high specific surface area (1294 m2 g?1). The specific capacitances of HPC and HPC/PANI (with a surface area of 923 m2 g?1) electrode are 383 and 1080 F g?1 in 1 m H2SO4, respectively. Furthermore, an asymmetric supercapacitor based on HPC/PANI as positive electrode and HPC as negative electrode is successfully assembled with a voltage window of 0–1.8 V in 1 m Na2SO4 aqueous electrolyte, exhibiting high specific capacitance (134 F g?1), high energy density (60.3 Wh kg?1) and power density (18 kW kg?1), and excellent cycling stability (91.6% capacitance retention after 5000 cycles).  相似文献   
33.
Polo-like kinase 1 (PLK1) plays an important role in the initiation, maintenance, and completion of mitosis. Dysfunction of PLK1 may promote cancerous transformation and drive its progression. PLK1 overexpression has been found in a variety of human cancers and was associated with poor prognoses in cancers. Many studies have showed that inhibition of PLK1 could lead to death of cancer cells by interfering with multiple stages of mitosis. Thus, PLK1 is expected to be a potential target for cancer therapy. In this article, we examined PLK1’s structural characteristics, its regulatory roles in cell mitosis, PLK1 expression, and its association with survival prognoses of cancer patients in a wide variety of cancer types, PLK1 interaction networks, and PLK1 inhibitors under investigation. Finally, we discussed the key issues in the development of PLK1-targeted cancer therapy.  相似文献   
34.
Currently, it is still a significant challenge to simultaneously boost various reactions by one electrocatalyst with high activity, excellent durability, as well as low cost. Herein, hybrid trifunctional electrocatalysts are explored via a facile one‐pot strategy toward an efficient oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The catalysts are rationally designed to be composed by FeCo nanoparticles encapsuled in graphitic carbon films, Co2P nanoparticles, and N,P‐codoped carbon nanofiber networks. The FeCo nanoparticles and the synergistic effect from Co2P and FeCo nanoparticles make the dominant contributions to the ORR, OER, and HER activities, respectively. Their bifunctional activity parameter (?E) for ORR and OER is low to 0.77 V, which is much smaller than those of most nonprecious metal catalysts ever reported, and comparable with state‐of‐the‐art Pt/C and RuO2 (0.78 V). Accordingly, the as‐assembled Zn–air battery exhibits a high power density of 154 mW cm?2 with a low charge–discharge voltage gap of 0.83 V (at 10 mA cm?2) and excellent stability. The as‐constructed overall water‐splitting cell achieves a current density of 10 mA cm?2 (at 1.68 V), which is comparable to the best reported trifunctional catalysts.  相似文献   
35.

Objective

Evaluate the predictive value of Boston Acute Stroke Imaging Scale (BASIS) in acute ischemic stroke in Chinese population.

Methods

This was a retrospective study. 566 patients of acute ischemic stroke were classified as having a major stroke or minor stroke based on BASIS. We compared short-term outcome (death, occurrence of complications, admission to intensive care unit [ICU] or neurological intensive care unit [NICU]), long-term outcome (death, recurrence of stroke, myocardial infarction, modified Rankin scale) and economic index including in-hospital cost and length of hospitalization. Continuous variables were compared by using the Student t test or Kruskal-Wallis test. Categorical variables were tested with the Chisquare test. Cox regression analysis was applied to identify whether BASIS was the independent predictive variable of death.

Results

During hospitalization, 9 patients (4.6%) died in major stroke group while no patients died in minor stroke group (p<0.001), 12 patients in the major stroke group and 5 patients in minor stroke group were admitted to ICU/NICU (p = 0.001). There were more complications (cerebral hernia, pneumonia, urinary tract infection) in major stroke group than minor stroke group (p<0.05). Meanwhile, the average cost of hospitalization in major stroke group was 3,100 US$ and 1,740 US$ in minor stroke group (p<0.001); the average length of stay in major and minor stroke group was 21.3 days and 17.3 days respectively (p<0.001). Results of the follow-up showed that 52 patients (26.7%) died in major stroke group while 56 patients (15.1%) died in minor stroke group (P<0.001). 62.2% of the patients in major stroke group and 80.4% of the patients in minor stroke group were able to live independently (P = 0.002). The survival analysis showed that patients with major stroke had 80% higher of risk of death than patients with minor stroke even after adjusting traditional atherosclerotic factors and NIHSS at baseline (HR = 1.8, 95% CI: 1.1–3.1).

Conclusion

BASIS can predict in-hospital mortality, occurrence of complication, length of stay and hospitalization cost of the acute ischemic stroke patients and can also estimate the long term outcome (death and the dependency). BASIS could and should be used as a dichotomous stroke classification system in the daily practice.  相似文献   
36.
Genetic modification offers alternative strategies to traditional animal breeding. However, the food safety of genetically modified (GM) animals has attracted increasing levels of concern. In this study, we produced GM sheep overexpressing TLR4, and the transgene-positive offsprings (F1) were confirmed using the polymerase chain reaction (PCR) and Southern blot. The expression of TLR4 was 2.5-fold compared with that of the wild-type (WT) sheep samples. During the 90-day safety study, Sprague-Dawley rats were fed with three different dietary concentrations (3.75%, 7.5%, and 15% wt/wt) of GM sheep meat, WT sheep meat or a commercial diet (CD). Blood samples from the rats were collected and analyzed for hematological and biochemical parameters, and then compared with hematological and biochemical reference ranges. Despite a few significant differences among the three groups in some parameters, all other values remained within the normal reference intervals and thus were not considered to be affected by the treatment. No adverse diet-related differences in body weights or relative organ weights were observed. Furthermore, no differences were observed in the gross necropsy findings or microscopic pathology of the rats whose diets contained the GM sheep meat compared with rats whose diets contained the WT sheep meat. Therefore, the present 90-day rat feeding study suggested that the meat of GM sheep overexpressing TLR4 had no adverse effect on Sprague-Dawley rats in comparison with WT sheep meat. These results provide valuable information regarding the safety assessment of meat derived from GM animals.  相似文献   
37.
Wang X 《Genomics》2012,99(2):90-95
Two-gene classifiers have attracted a broad interest for their simplicity and practicality. Most existing two-gene classification algorithms were involved in exhaustive search that led to their low time-efficiencies. In this study, we proposed two new two-gene classification algorithms which used simple univariate gene selection strategy and constructed simple classification rules based on optimal cut-points for two genes selected. We detected the optimal cut-point with the information entropy principle. We applied the two-gene classification models to eleven cancer gene expression datasets and compared their classification performance to that of some established two-gene classification models like the top-scoring pairs model and the greedy pairs model, as well as standard methods including Diagonal Linear Discriminant Analysis, k-Nearest Neighbor, Support Vector Machine and Random Forest. These comparisons indicated that the performance of our two-gene classifiers was comparable to or better than that of compared models.  相似文献   
38.
为了探究雌激素受体2 (Estrogen receptor 2, ESR2)基因在绵羊各组织的表达及其多态性与产羔数之间的关系,本研究利用半定量PCR和实时荧光定量PCR技术检测ESR2基因在不同繁殖力小尾寒羊群体组织中的相对表达量,同时采用Sequenom MassARRAY誖SNP技术对多羔品种绵羊(小尾寒羊,湖羊,策勒黑羊)和单羔品种绵羊(苏尼特羊,草原型藏羊,滩羊) ESR2基因g.73324006C>T位点进行检测,并与小尾寒羊产羔数进行关联分析。半定量PCR表明,ESR2基因在单、多羔小尾寒羊子宫中高表达,在其它组织中等或低丰度表达;单羔群体、多羔群体间荧光定量PCR表明,ESR2基因在单羔小尾寒羊垂体表达量显著高于多羔小尾寒羊(p<0.05);群体遗传学分析表明,g.73324006C>T在小尾寒羊群体中表现为低度多态(PIC<0.25),在滩羊群体中处于中度多态(0.25T在小尾寒羊群体处于哈代温伯格平衡状态(p>0.05);关联分析表明,g.73324006C>T位点多态性与小尾寒羊第一胎、第二胎、第三胎产羔数及平均产羔数均显著关联(p<0.05),CC型各胎产羔数均高于TC型。与FecB (A746G)基因组合后发现,GG-CC和AG-CC基因型母羊产羔数显著高于AA-TC、AA-CC、AG-TC基因型组合(p<0.05)。综上,ESR2与小尾寒羊产羔数密切相关,g.73324006C>T可作为绵羊产羔性状选育的潜在分子标记。  相似文献   
39.
Accurate molecular classification of cancer using simple rules   总被引:1,自引:0,他引:1  

Background

One intractable problem with using microarray data analysis for cancer classification is how to reduce the extremely high-dimensionality gene feature data to remove the effects of noise. Feature selection is often used to address this problem by selecting informative genes from among thousands or tens of thousands of genes. However, most of the existing methods of microarray-based cancer classification utilize too many genes to achieve accurate classification, which often hampers the interpretability of the models. For a better understanding of the classification results, it is desirable to develop simpler rule-based models with as few marker genes as possible.

Methods

We screened a small number of informative single genes and gene pairs on the basis of their depended degrees proposed in rough sets. Applying the decision rules induced by the selected genes or gene pairs, we constructed cancer classifiers. We tested the efficacy of the classifiers by leave-one-out cross-validation (LOOCV) of training sets and classification of independent test sets.

Results

We applied our methods to five cancerous gene expression datasets: leukemia (acute lymphoblastic leukemia [ALL] vs. acute myeloid leukemia [AML]), lung cancer, prostate cancer, breast cancer, and leukemia (ALL vs. mixed-lineage leukemia [MLL] vs. AML). Accurate classification outcomes were obtained by utilizing just one or two genes. Some genes that correlated closely with the pathogenesis of relevant cancers were identified. In terms of both classification performance and algorithm simplicity, our approach outperformed or at least matched existing methods.

Conclusion

In cancerous gene expression datasets, a small number of genes, even one or two if selected correctly, is capable of achieving an ideal cancer classification effect. This finding also means that very simple rules may perform well for cancerous class prediction.  相似文献   
40.
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