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61.
Badra Bouamama Asma Ben Salem Fatma Ben Youssef Soumaya Chaieb Mohamed-Hbib Jaafoura Ahmed Mliki Abdelwahed Ghorbel 《In vitro cellular & developmental biology. Plant》2011,47(2):321-327
The regeneration ability of a Tunisian barley accession originated from Kerkena islands was monitored through somatic embryogenesis
and organogenesis. To prevent or to reduce normal germination, longitudinally bisected as well as base-wounded mature caryopses
were cultured on a modified Chée and Pool-based medium (CP) enriched with different phytohormonal combinations. The greatest
embryogenesis response was obtained when base-wounded caryopses were cultured on CP enriched with 2 mg/l chlorophenoxyacetic
acid + 2.5 mg/l kinetin (76.85%). The same combination coupled to longitudinally bisected caryopses led to the embryogenic
induction at the hypocotyl base of the germinated caryopses (61.9%). Embryogenic calluses differentiated into globular, heart-shaped,
torpedo, and fully differentiated stages of somatic embryos on hormone-free Murashige and Skoog-based medium. Rooted plantlets
were successfully transferred to soil and grown to maturity in the greenhouse and produced fertile seeds within 3 mo. On the
other hand, organogenesis was achieved on CP enriched with 2 mg/l 2,4-dichlorophenoxyacetic acid + 2.5 mg/l kinetin. Histological
aspects and scanning electron microscopy of both regeneration methods confirmed further the embryogenic and organogenic nature
of the established processes. This efficient plant regeneration system provides a foundation for generating transgenic plants
and germplasm preservation of “Kerkena” barley accession. 相似文献
62.
华北石质山地侧柏人工林C、N、P生态化学计量特征的季节变化 总被引:5,自引:0,他引:5
以北京九龙山自然保护区幼龄侧柏人工林为研究对象,对其不同生长季节叶、枝、根(0—10 cm、10—20 cm土层)的碳(C)、氮(N)、磷(P)含量及其生态化学计量学特征进行了分析,深入探讨了生长季节与器官以及两因素交互作用对以上特征的影响,研究有助于理解植物各性状之间的相互作用以及植物生长过程中资源的利用和分配状况。结果表明:1)不同器官间C含量为414.97—461.58 g/kg,枝最大,根(0—10 cm)最小;N含量为6.57—14.28 g/kg,叶最大,枝最小;P含量为0.39—1.28 g/kg,叶最大,根(10—20 cm)最小;C∶N为31.76—70.98,枝最大,叶最小;C∶P为369.93—1099.20,根(10—20 cm)最大,叶最小;N∶P为9.21—23.81,根(0—10 cm)最大,枝最小。整个生长季节中侧柏各器官C含量最稳定,变异系数均小于7%;P含量变异性最大,变异系数均超过15%,N含量变异性介于两者之间;各器官中C∶N和N∶P较C∶P更为稳定,C、N与P具有较好的耦合协同性,C∶P和N∶P的变化主要取决于P的变化。2)器官对C、N、P含量及其化学计量关系均存在显著影响,生长季节对N和P含量存在显著影响,两者交互作用只对P含量存在显著影响,器官对侧柏C、N、P含量及其化学计量变异的贡献大于生长季节。3)侧柏各器官间C、N、P含量及其化学计量比相关性多数未达到显著性水平,仅有叶与枝中的P及C∶P显著相关,说明侧柏器官分化过程中各器官对元素的吸收利用具有特异性。侧柏叶片N∶P14,说明生长季节里幼龄侧柏人工林更多受到N限制。 相似文献
63.
利用较少分子信息预测肝细胞癌类型对患者的个性化治疗十分关键。探索已知的与肝细胞癌预后相关的信号通路,共发现41个关键基因。随后,运用机器学习的方法对其构建风险预测模型,并在4个肝细胞癌数据集上进行验证。结果显示,该模型能将肝细胞癌患者分成两个预后差异显著的类型:癌症基因图谱(The cancer genome atlas,TCGA)数据集交叉验证的平均log rank P值为0.03;其他测试数据集的log rank P 值分别为0.000 38、0.002 1和0.01。生物信息学分析显示肝细胞癌的预后与细胞周期等信号通路显著相关,并筛选出12个潜在的肝细胞癌分子标志物。研究结果表明,基于41个基因构建的肝细胞癌预后模型具有较好的稳健性和准确的风险预测能力。 相似文献
64.
65.
目的:制备链亲和素标记的人白细胞介素-2(SA-hIL2)融合蛋白,并研究其生物学功能。方法:构建SA-L-IL2-pET24重组表达质粒,在大肠杆菌中表达SA-hIL2融合蛋白,对表达的SA-hIL2融合蛋白采用镍金属螯合(Ni-NTA)层析柱进行纯化,透析复性。CCK-8法检测SA-hIL2融合蛋白对PHA刺激的人外周血淋巴细胞的增值活性,流式细胞仪分析SA-hIL2融合蛋白对生物素化的B16.F10肿瘤细胞表面锚定修饰效率。结果:SA-hIL2在大肠杆菌中实现了高效表达,约占菌体总蛋白的20%,制备的SA-hIL2融合蛋白纯度达到95%,并具有双重活性,即hIL-2促进PHA刺激的人外周血淋巴细胞的增值活性和SA介导的高效结合至已生物素化的B16.F10肿瘤细胞表面的功能(表面锚定修饰效率约95%)。结论:研制的SA-hIL2融合蛋白具有双重活性,可为研制表面修饰的新型肿瘤细胞疫苗提供基础。 相似文献
66.
FA Miles 《Current opinion in neurobiology》1997,7(6):867-871
Observers moving through a texture three-dimensional world experience potentially confusing patterns of optic flow. Recent experiments on monkeys and humans have revealed the existence of rapid, yet cortically mediated, reflex eye movements that automatically single out images in the plane of fixation for stabilization and ignore images that are nearer or further. 相似文献
67.
Background
Thoracotomy is associated with severe pain that may persist for years. Acupuncture is a complementary therapy with a proven role in pain control. A randomized trial showed that acupuncture was effective in controlling pain after abdominal surgery, but the efficacy of this technique for the treatment of thoracotomy pain has not been established. We developed a novel technique for convenient application of acupuncture to patients undergoing thoracotomy, and in a Phase II trial evaluated the safety of this intervention and the feasibility of doing a randomized trial.Methods
Adult patients scheduled for unilateral thoracotomy with preoperative epidural catheter placement received acupuncture immediately prior to surgery. Eighteen semi-permanent intradermal needles were inserted on either side of the spine, and four were inserted in the legs and auricles. Needles were removed after four weeks. Using a numerical rating scale, pain was measured on the first five postoperative days. After discharge, pain was assessed using the Brief Pain Inventory at 7, 30, 60 and 90 days.Results
Thirty-six patients were treated with acupuncture. Of these, 25, 23, and 22 patients provided data at 30, 60, and 90 days, respectively. The intervention was well tolerated by patients with only one minor and transient adverse event of skin ulceration.Conclusion
The rate of data completion met our predefined criterion for determining a randomized trial to be feasible (at least 75% of patients tolerated the intervention and provided evaluable data). This novel intervention is acceptable to patients undergoing thoracotomy and does not interfere with standard preoperative care. There was no evidence of important adverse events. We are now testing the hypothesis that acupuncture significantly adds to standard perioperative pain management in a randomized trial. 相似文献68.
Mitochondrial DNA sequence variation in the spruce budworm species complex (Choristoneura: Lepidoptera) 总被引:5,自引:0,他引:5
A combination of polymerase-chain-reaction amplification and automated DNA
sequencing was used to survey variation in a species complex of pest
insects, the spruce budworms (Choristoneura fumiferana species group), and
an outgroup species, C. rosaceana. We sequenced an mtDNA region of 1,573 bp
that extends from the middle of cytochrome oxidase subunit I (COI) through
tRNA leucine (UUR) to the end of cytochrome oxidase subunit II. In
addition, we examined levels of intraspecific variation within a 470-bp
region of the COI gene. Choristoneura fumiferana clearly represented the
oldest lineage within its species group, with 2.7%-2.9% sequence divergence
from the other species. In contrast, the four remaining species (C. pinus,
C. biennis, C. occidentalis, and C. orae) had closely related or identical
mtDNA, with < 1% divergence among most of their haplotypes. Despite its
older lineage and widespread geographic distribution, C. fumiferana showed
significantly lower intraspecific genetic diversity than did C.
occidentalis. Choristoneura orae shared haplotypes with C. occidentalis and
C. biennis, and species-level separation of these three species was not
supported. Two divergent, uncommon haplotypes were also found in C.
occidentalis and C. biennis. The divergent haplotype in C. biennis had an
unusually high number of inferred amino acid replacements, suggesting
selective differences between mitochondrial DNA haplotypes.
Transition:transversion ratios in Choristoneura paralleled those found in
Drosophila; transition:transversion ratios were highest in closely related
sequences but decreased with increasing sequence divergence. Nucleotide
composition showed an A+T bias that was near the high end of the range
known for insects. This work illustrates the potential utility of direct
DNA sequencing in assessing population structures, species limits, and
phylogenetic relationships among organisms that have not previously been
subjected to DNA analysis.
相似文献
69.
Carmen Lai Hugo M Horlings Marc J van de Vijver Eric H van Beers Petra M Nederlof Lodewyk FA Wessels Marcel JT Reinders 《BMC bioinformatics》2007,8(1):422
Background
Array comparative genome hybridization (aCGH) provides information about genomic aberrations. Alterations in the DNA copy number may cause the cell to malfunction, leading to cancer. Therefore, the identification of DNA amplifications or deletions across tumors may reveal key genes involved in cancer and improve our understanding of the underlying biological processes associated with the disease. 相似文献70.
Cui F Ding A Li J Zhao C Li X Feng D Wang X Wang L Gao J Wang H 《Journal of genetics》2011,90(3):409-425
Kernel dimensions (KD) contribute greatly to thousand-kernel weight (TKW) in wheat. In the present study, quantitative trait loci (QTL) for TKW, kernel length (KL), kernel width (KW) and kernel diameter ratio (KDR) were detected by both conditional and unconditional QTL mapping methods. Two related F(8:9) recombinant inbred line (RIL) populations, comprising 485 and 229 lines, respectively, were used in this study, and the trait phenotypes were evaluated in four environments. Unconditional QTL mapping analysis detected 77 additive QTL for four traits in two populations. Of these, 24 QTL were verified in at least three trials, and five of them were major QTL, thus being of great value for marker assisted selection in breeding programmes. Conditional QTL mapping analysis, compared with unconditional QTL mapping analysis, resulted in reduction in the number of QTL for TKW due to the elimination of TKW variations caused by its conditional traits; based on which we first dissected genetic control system involved in the synthetic process between TKW and KD at an individual QTL level. Results indicated that, at the QTL level, KW had the strongest influence on TKW, followed by KL, and KDR had the lowest level contribution to TKW. In addition, the present study proved that it is not all-inclusive to determine genetic relationships of a pairwise QTL for two related/causal traits based on whether they were co-located. Thus, conditional QTL mapping method should be used to evaluate possible genetic relationships of two related/causal traits. 相似文献