全文获取类型
收费全文 | 229篇 |
免费 | 23篇 |
国内免费 | 18篇 |
出版年
2024年 | 5篇 |
2023年 | 4篇 |
2022年 | 12篇 |
2021年 | 21篇 |
2020年 | 10篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 15篇 |
2013年 | 14篇 |
2012年 | 16篇 |
2011年 | 18篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 12篇 |
2007年 | 12篇 |
2006年 | 6篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有270条查询结果,搜索用时 15 毫秒
1.
Adsorption of fungal spores on a synthetic polymer - High Density Polyethylene was successfully achieved using different pretreatments. Sonication of beads followed by ferric nitrate treatment or use of 0.1% tributyrin gave adsorption upto 46%. Use of dichloromethane as a solvent for sonication is recommended for its better performance in reuse studies (upto 5 times without much decrease in activity). 100 g of immobilized biocatabyst in a 7 L Fluidized Bed Bioreactor was found to perform better than shaker flask at a much lower power input. 相似文献
2.
A highly conserved nuclear gene for low-level phylogenetics: elongation factor-1 alpha recovers morphology-based tree for heliothine moths 总被引:8,自引:2,他引:6
Cho S; Mitchell A; Regier JC; Mitter C; Poole RW; Friedlander TP; Zhao S 《Molecular biology and evolution》1995,12(4):650-656
Molecular systematists need increased access to nuclear genes. Highly
conserved, low copy number protein-encoding nuclear genes have attractive
features for phylogenetic inference but have heretofore been applied mostly
to very ancient divergences. By virtue of their synonymous substitutions,
such genes should contain a wealth of information about lower-level
taxonomic relationships as well, with the advantage that amino acid
conservatism makes both alignment and primer definition straightforward. We
tested this postulate for the elongation factor-1 alpha (EF-1 alpha) gene
in the noctuid moth subfamily Heliothinae, which has probably diversified
since the middle Tertiary. We sequenced 1,240 bp in 18 taxa representing
heliothine groupings strongly supported by previous morphological and
allozyme studies. The single most parsimonious gene tree and the
neighbor-joining tree for all nucleotides show almost complete concordance
with the morphological tree. Homoplasy and pairwise divergence levels are
low, transition/transversion ratios are high, and phylogenetic information
is spread evenly across gene regions. The EF-1 alpha gene and presumably
other highly conserved genes hold much promise for phylogenetics of
Tertiary age eukaryote groups.
相似文献
3.
S Lele 《American journal of physical anthropology》1991,85(4):407-417
The unusual strategy for comparing biological shapes is to use some kind of superimposition of the two forms under study and then look at the "residuals" as the shape change. In this paper, I take a careful look at this general strategy and point out some subtle but inherent and important pitfalls. Additionally an alternative approach based on Euclidean Distance Matrix representation is presented. It is applicable to two- as well as three-dimensional objects. 相似文献
4.
P. P. Lele 《Radiation and environmental biophysics》1980,17(3):205-217
Summary The feasibility, and the biophysical and engineering concepts underlying the use of electromagnetic energy and ultrasound for production of deep, local hyperthermia are discussed. Focused ultrasound currently is the only modality that can be used for producing controllable levels of hyperthermia localized to deep seated tumors, non-invasively and safely. The ultrasonic focus needs to moved within the tissues around the periphery of the tumor to achieve uniform temperature distributions. 相似文献
5.
Jun Wang Shaojun Yu Guofeng Chen Muxing Kang Xiaoli Jin Yi Huang Lele Lin Dan Wu Lie Wang Jian Chen 《Journal of cellular and molecular medicine》2020,24(15):8491-8504
Colorectal cancer (CRC) is one of the most commonly diagnosed cancers with an estimated 1.8 million new cases worldwide and associated with high mortality rates of 881 000 CRC‐related deaths in 2018. Screening programs and new therapies have only marginally improved the survival of CRC patients. Immune‐related genes (IRGs) have attracted attention in recent years as therapeutic targets. The aim of this study was to identify an immune‐related prognostic signature for CRC. To this end, we combined gene expression and clinical data from the CRC data sets of The Cancer Genome Atlas (TCGA) into an integrated immune landscape profile. We identified a total of 476 IRGs that were differentially expressed in CRC vs normal tissues, of which 18 were survival related according to univariate Cox analysis. Stepwise multivariate Cox proportional hazards analysis established an immune‐related prognostic signature consisting of SLC10A2, FGF2, CCL28, NDRG1, ESM1, UCN, UTS2 and TRDC. The predictive ability of this signature for 3‐ and 5‐year overall survival was determined using receiver operating characteristics (ROC), and the respective areas under the curve (AUC) were 79.2% and 76.6%. The signature showed moderate predictive accuracy in the validation and GSE38832 data sets as well. Furthermore, the 8‐IRG signature correlated significantly with tumour stage, invasion, lymph node metastasis and distant metastasis by univariate Cox analysis, and was established an independent prognostic factor by multivariate Cox regression analysis for CRC. Gene set enrichment analysis (GSEA) revealed a relationship between the IRG prognostic signature and various biological pathways. Focal adhesions and ECM‐receptor interactions were positively correlated with the risk scores, while cytosolic DNA sensing and metabolism‐related pathways were negatively correlated. Finally, the bioinformatics results were validated by real‐time RT?qPCR. In conclusion, we identified and validated a novel, immune‐related prognostic signature for patients with CRC, and this signature reflects the dysregulated tumour immune microenvironment and has a potential for better CRC patient management. 相似文献
6.
Fang Liu Xiaoping Zhang Mingdao Wang Lele Guo Yingyue Yang 《Bioscience, biotechnology, and biochemistry》2020,84(7):1521-1528
ABSTRACT Sterols are verified to be able to produce polycyclic aromatic hydrocarbons during its pyrolysis. In this study, a kind of Aspergillus fumigatus (LSD-1) was isolated from cigar leaves, and the biosorption effects on the stigmasterol, β-sitosterol, campesterol, cholesterol, and ergosterol by using living and dead biomass of LSD-1 were investigated. The results showed that both living and dead biomass could efficiently remove these sterols in aqueous solution and tobacco waste extract (TWE). Interestingly, compared with the living biomass of LSD-1, the dead biomass of LSD-1 not only kept a high adsorption efficiency but also did not produce ergosterol. Overall, dead biomass of LSD-1 was a more suitable biosorbent to sterols in TWE. Furthermore, Brunner-Emmet-Teller (BET), Fourier transformed infrared spectrometer (FTIR) and scanning electron microscope (SEM) analysis were used to explore the biosorption process of living and dead biomass and their differences, suggesting that the biosorption of sterols was a physical process. 相似文献
7.
8.
中国建立国家公园的目的是保护自然生态系统的完整性和原真性, 促进生物多样性保护。国家公园的完整性和原真性评价是国家公园的布局规划、边界范围确定以及功能区划等研究的前提条件。为了评估国家公园自然生态系统完整性和原真性状态, 本文基于陆地自然生态系统的结构和功能, 通过指标筛选、专家咨询、指标量化和建立综合评价模型, 构建了陆地自然生态系统完整性与原真性的评价指标体系及其量化评价方法。该评价方法包括5个自然生态系统完整性指标、5个自然生态系统原真性指标和2个综合评价指标。以浙江省钱江源国家公园体制试点为例, 本文初步评估了其生态系统完整性与原真性状态, 并对评价结果进行了分级。按照本研究的评价方法, 钱江源国家公园体制试点的自然生态系统完整性评价结果为52.83%, 评价等级为较差; 自然生态系统原真性评价结果为87.06%, 评价等级为好。钱江源国家公园体制试点有待关注和提升的指标有保护区域完整性指数(27.00%)和旗舰种适宜生境完整性指数(53.04%)。最后, 本文结合研究区域评价结果对生态系统完整性和原真性领域应关注的问题进行了讨论。该自然生态系统完整性和原真性评价方法可提供一种评价指标覆盖较全面、数据易获取, 且评价结果易被决策者和管理者理解的评价思路。 相似文献
9.
Fang Yuan Dana E. Tabor Richard K. Nelson Hongjiang Yuan Yijia Zhang Jenny Nuxoll Kimberly K. Bynoté Subodh M. Lele Dong Wang Karen A. Gould 《PloS one》2013,8(11)
We evaluated the ability of a macromolecular prodrug of dexamethasone (P-Dex) to treat lupus nephritis in (NZB × NZW)F1 mice. We also explored the mechanism underlying the anti-inflammatory effects of this prodrug. P-Dex eliminated albuminuria in most (NZB × NZW)F1 mice. Furthermore, P-Dex reduced the incidence of severe nephritis and extended lifespan in these mice. P-Dex treatment also prevented the development of lupus-associated hypertension and vasculitis. Although P-Dex did not reduce serum levels of anti-dsDNA antibodies or glomerular immune complexes, P-Dex reduced macrophage recruitment to the kidney and attenuated tubulointerstitial injury. In contrast to what was observed with free dexamethasone, P-Dex did not induce any deterioration of bone quality. However, P-Dex did lead to reduced peripheral white blood cell counts and adrenal gland atrophy. These results suggest that P-Dex is more effective and less toxic than free dexamethasone for the treatment of lupus nephritis in (NZB × NZW)F1 mice. Furthermore, the data suggest that P-Dex may treat nephritis by attenuating the renal inflammatory response to immune complexes, leading to decreased immune cell infiltration and diminished renal inflammation and injury. 相似文献
10.
AV Shevchenko IG Budzanivska TP Shevchenko VP Polischuk D Spaar 《Archives Of Phytopathology And Plant Protection》2013,46(2):139-146
The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants. 相似文献