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Minghui Xu Junmin Qian Aili Suo Hongjie Wang Xueqing Yong Xuefeng Liu Rongrong Liu 《Carbohydrate polymers》2013
To minimize the side effect of chemotherapy, a novel reduction/pH dual-sensitive drug nanocarrier, based on PEGylated dithiodipropionate dihydrazide (TPH)-modified hyaluronic acid (PEG-SS-HA copolymer), was developed for targeted delivery of doxorubicin (DOX) to hepatocellular carcinoma. The copolymer was synthesized by reductive amination via Schiff's base formation between TPH-modified HA and galactosamine-conjugated poly(ethylene glycol) aldehyde/methoxy poly(ethylene glycol) aldehyde. Conjugation of DOX to PEG-SS-HA copolymer was accomplished through the hydrazone linkage formed between DOX and PEG-SS-HA, and confirmed by FTIR and 1H NMR spectra. The polymer–DOX conjugate could self-assemble into spherical nanoparticles (∼150 nm), as indicated by TEM and DLS. In vitro release studies showed that the DOX-loaded nanoparticles could release DOX rapidly under the intracellular levels of pH and glutathiose. Cellular uptake experiments demonstrated that the nanoparticles could be efficiently internalized by HepG2 cells. These results indicate that the PEG-SS-HA copolymer holds great potential for targeted intracellular delivery of DOX. 相似文献
63.
Chen Xu Nan Zhang Qianyu Huo Minghui Chen Rengfeng Wang Zhili Liu Xue Li Yunde Liu Huijing Bao 《Analytical biochemistry》2016
In this article, we discuss the polymerase chain reaction (PCR)–hybridization assay that we developed for high-throughput simultaneous detection and differentiation of Ureaplasma urealyticum and Ureaplasma parvum using one set of primers and two specific DNA probes based on urease gene nucleotide sequence differences. First, U. urealyticum and U. parvum DNA samples were specifically amplified using one set of biotin-labeled primers. Furthermore, amine-modified DNA probes, which can specifically react with U. urealyticum or U. parvum DNA, were covalently immobilized to a DNA–BIND plate surface. The plate was then incubated with the PCR products to facilitate sequence-specific DNA binding. Horseradish peroxidase–streptavidin conjugation and a colorimetric assay were used. Based on the results, the PCR–hybridization assay we developed can specifically differentiate U. urealyticum and U. parvum with high sensitivity (95%) compared with cultivation (72.5%). Hence, this study demonstrates a new method for high-throughput simultaneous differentiation and detection of U. urealyticum and U. parvum with high sensitivity. Based on these observations, the PCR–hybridization assay developed in this study is ideal for detecting and discriminating U. urealyticum and U. parvum in clinical applications. 相似文献
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Live attenuated coccidiosis vaccines could be used as powerful carriers, expressing exogenous viral and bacterial antigens, to induce protective immunity against pathogenic organisms. We investigated the ability of Eimeria tenella to express an exogenous gene in vitro. Eimeria tenella sporozoites were transfected with the plasmid pH4-2EYFP-Actin3 containing the yellow fluorescent protein gene (yfp) and inoculated into primary chicken kidney cells (PCKCs), followed by incubation at 41 C in a 5% CO2 chamber. Fluorescent sporozoites were observed as early as 15-20 hr post-inoculation (PI). Fluorescence displayed by the expressed YFP protein was visible throughout the schizogony and gametogony stages of the tranfected E. tenella. Fluorescent oocysts were found between 200-327 hr PI. Higher fluorescence intensity was observed in the nucleus than in other compartments of the transfectants, while little or no fluorescence was seen in the refractile globule. The diversity of schizonts, particularly of the first generation, was presented by fluorescent nuclei arranged in different patterns. Our results demonstrated the ability of E. tenella to express an exogenous gene throughout the endogenous development in vitro. Completion of the endogenous development of transfected E. tenella in cell cultures will facilitate the study of foreign antigen expression in Eimeria spp., paving the way for the development of an Eimeria spp. vector vaccine that also carries and delivers other vaccines by oral administration. 相似文献
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Responses of Bacterial Communities to Simulated Climate Changes in Alpine Meadow Soil of the Qinghai-Tibet Plateau 总被引:1,自引:0,他引:1
Junpeng Rui Jiabao Li Shiping Wang Jiaxing An Wen-tso Liu Qiaoyan Lin Yunfeng Yang Zhili He Xiangzhen Li 《Applied and environmental microbiology》2015,81(17):6070-6077
The soil microbial community plays an important role in terrestrial carbon and nitrogen cycling. However, microbial responses to climate warming or cooling remain poorly understood, limiting our ability to predict the consequences of future climate changes. To address this issue, it is critical to identify microbes sensitive to climate change and key driving factors shifting microbial communities. In this study, alpine soil transplant experiments were conducted downward or upward along an elevation gradient between 3,200 and 3,800 m in the Qinghai-Tibet plateau to simulate climate warming or cooling. After a 2-year soil transplant experiment, soil bacterial communities were analyzed by pyrosequencing of 16S rRNA gene amplicons. The results showed that the transplanted soil bacterial communities became more similar to those in their destination sites and more different from those in their “home” sites. Warming led to increases in the relative abundances in Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria and decreases in Acidobacteria, Betaproteobacteria, and Deltaproteobacteria, while cooling had opposite effects on bacterial communities (symmetric response). Soil temperature and plant biomass contributed significantly to shaping the bacterial community structure. Overall, climate warming or cooling shifted the soil bacterial community structure mainly through species sorting, and such a shift might correlate to important biogeochemical processes such as greenhouse gas emissions. This study provides new insights into our understanding of soil bacterial community responses to climate warming and cooling. 相似文献
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Fiala KA Brown JA Ling H Kshetry AK Zhang J Taylor JS Yang W Suo Z 《Journal of molecular biology》2007,365(3):590-602
Numerous template-dependent DNA polymerases are capable of catalyzing template-independent nucleotide additions onto blunt-end DNA. Such non-canonical activity has been hypothesized to increase the genomic hypermutability of retroviruses including human immunodeficiency viruses. Here, we employed pre-steady state kinetics and X-ray crystallography to establish a mechanism for blunt-end additions catalyzed by Sulfolobus solfataricus Dpo4. Our kinetic studies indicated that the first blunt-end dATP incorporation was 80-fold more efficient than the second, and among natural deoxynucleotides, dATP was the preferred substrate due to its stronger intrahelical base-stacking ability. Such base-stacking contributions are supported by the 41-fold higher ground-state binding affinity of a nucleotide analog, pyrene nucleoside 5'-triphosphate, which lacks hydrogen bonding ability but possesses four conjugated aromatic rings. A 2.05 A resolution structure of Dpo4*(blunt-end DNA)*ddATP revealed that the base and sugar of the incoming ddATP, respectively, stack against the 5'-base of the opposite strand and the 3'-base of the elongating strand. This unprecedented base-stacking pattern can be applied to subsequent blunt-end additions only if all incorporated dAMPs are extrahelical, leading to predominantly single non-templated dATP incorporation. 相似文献
68.
Renying Wang Peijing Zhang Jingjing Wang Lifeng Ma Weigao E Shengbao Suo Mengmeng Jiang Jiaqi Li Haide Chen Huiyu Sun Lijiang Fei Ziming Zhou Yincong Zhou Yao Chen Weiqi Zhang Xinru Wang Yuqing Mei Zhongyi Sun Chengxuan Yu Jikai Shao Yuting Fu Yanyu Xiao Fang Ye Xing Fang Hanyu Wu Qile Guo Xiunan Fang Xia Li Xianzhi Gao Dan Wang Peng-Fei Xu Rui Zeng Gang Xu Lijun Zhu Lie Wang Jing Qu Dan Zhang Hongwei Ouyang He Huang Ming Chen Shyh-Chang NG Guang-Hui Liu Guo-Cheng Yuan Guoji Guo Xiaoping Han 《Nucleic acids research》2023,51(2):501
Individual cells are basic units of life. Despite extensive efforts to characterize the cellular heterogeneity of different organisms, cross-species comparisons of landscape dynamics have not been achieved. Here, we applied single-cell RNA sequencing (scRNA-seq) to map organism-level cell landscapes at multiple life stages for mice, zebrafish and Drosophila. By integrating the comprehensive dataset of > 2.6 million single cells, we constructed a cross-species cell landscape and identified signatures and common pathways that changed throughout the life span. We identified structural inflammation and mitochondrial dysfunction as the most common hallmarks of organism aging, and found that pharmacological activation of mitochondrial metabolism alleviated aging phenotypes in mice. The cross-species cell landscape with other published datasets were stored in an integrated online portal—Cell Landscape. Our work provides a valuable resource for studying lineage development, maturation and aging. 相似文献
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