全文获取类型
收费全文 | 631篇 |
免费 | 68篇 |
国内免费 | 94篇 |
专业分类
化学 | 544篇 |
力学 | 23篇 |
综合类 | 22篇 |
数学 | 49篇 |
物理学 | 155篇 |
出版年
2024年 | 6篇 |
2023年 | 16篇 |
2022年 | 80篇 |
2021年 | 71篇 |
2020年 | 55篇 |
2019年 | 34篇 |
2018年 | 15篇 |
2017年 | 26篇 |
2016年 | 28篇 |
2015年 | 31篇 |
2014年 | 41篇 |
2013年 | 50篇 |
2012年 | 37篇 |
2011年 | 33篇 |
2010年 | 34篇 |
2009年 | 28篇 |
2008年 | 28篇 |
2007年 | 19篇 |
2006年 | 23篇 |
2005年 | 23篇 |
2004年 | 21篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 3篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有793条查询结果,搜索用时 0 毫秒
121.
Thermo‐triggered Release of CRISPR‐Cas9 System by Lipid‐Encapsulated Gold Nanoparticles for Tumor Therapy 下载免费PDF全文
Dr. Peng Wang Dr. Lingmin Zhang Prof. Wenfu Zheng Dr. Liman Cong Zhaorong Guo Yangzhouyun Xie Le Wang Rongbing Tang Qiang Feng Prof. Yoh Hamada Prof. Kohsuke Gonda Prof. Zhijian Hu Prof. Xiaochun Wu Prof. Xingyu Jiang 《Angewandte Chemie (International ed. in English)》2018,57(6):1491-1496
CRISPR/Cas9 system is a powerful toolbox for gene editing. However, the low delivery efficiency is still a big hurdle impeding its applications. Herein, we report a strategy to deliver Cas9‐sgPlk‐1 plasmids (CP) by a multifunctional vehicle for tumor therapy. We condensed CPs on TAT peptide‐modified Au nanoparticles (AuNPs/CP, ACP) via electrostatic interactions, and coated lipids (DOTAP, DOPE, cholesterol, PEG2000‐DSPE) on the ACP to form lipid‐encapsulated, AuNPs‐condensed CP (LACP). LACP can enter tumor cells and release CP into the cytosol by laser‐triggered thermo‐effects of the AuNPs; the CP can enter nuclei by TAT guidance, enabling effective knock‐outs of target gene (Plk‐1) of tumor (melanoma) and inhibition of the tumor both in vitro and in vivo. This AuNPs‐condensed, lipid‐encapsulated, and laser‐controlled delivery system provides a versatile method for high efficiency CRISPR/Cas9 delivery and targeted gene editing for treatment of a wide spectrum of diseases. 相似文献
122.
The development of early and personalized diagnostic protocol with rapid response and high accuracy is considered the most promising avenue to advance point-of-care testing for tumor diagnosis and therapy. Given the growing awareness of the limitations of conventional tissue biopsy for gathering tumor information, considerable interest has recently been aroused in liquid biopsy. Among a myriad of analytical approaches proposed for liquid biopsy, microfluidics-based separation and purification techniques possess merits of high throughput, low samples consumption, high flexibility, low cost, high sensitivity, automation capability and enhanced spatio-temporal control. These characteristics endow microfluidics to serve as an emerging and promising tool in tumor diagnosis and prognosis by identifying specific circulating tumor biomarkers. In this review, we will put our focus on three key categories of circulating tumor biomarkers, namely, circulating tumor cells (CTCs), circulating exosomes, and circulating nucleic acids (cNAs), and discuss the significant roles of microfluidics in the separation and analysis of circulating tumor biomarkers. Recent advances in microfluidic separation and analysis of CTCs, exosomes, and cNAs will be highlighted and tabulated. Finally, the current challenges and future niches of using microfluidic techniques in the separation and analysis of circulating tumor biomarkers will be discussed. 相似文献
123.
Small sample sizes are very common in multivariate analysis. Sample sizes of 10–100 statistically independent objects (rejects
from processes or loading dock analysis, or patients with a rare disease), each with hundreds of data points, cause unstable
models with poor predictive quality. Model stability is assessed by comparing models that were built using slightly varying
training data. Iterated k-fold cross-validation is used for this purpose. Aggregation stabilizes models. It is possible to
assess the quality of the aggregated model without calculating further models. The validation and aggregation methods investigated
in this study apply to regression as well as to classification. These techniques are useful for analyzing data with large
numbers of variates, e.g., any spectral data like FT-IR, Raman, UV/VIS, fluorescence, AAS, and MS. FT-IR images of tumor tissue
were used in this study. Some tissue types occur frequently, while some are very rare. They are classified using LDA. Initial
models were severely unstable. Aggregation stabilizes the predictions. The hit rate increased from 67% to 82%. 相似文献
124.
Theresa Hune Dr. Salvatore Mamone Dr. Henning Schroeder Dr. Anil P. Jagtap Sonja Sternkopf Dr. Gabriele Stevanato Dr. Sergey Korchak Claudia Fokken Christoph A. Müller Andreas B. Schmidt Dr. Dorothea Becker Dr. Stefan Glöggler 《Chemphyschem》2023,24(2):e202200615
The metabolism of malignant cells differs significantly from that of healthy cells and thus, it is possible to perform metabolic imaging to reveal not only the exact location of a tumor, but also intratumoral areas of high metabolic activity. Herein, we demonstrate the feasibility of metabolic tumor imaging using signal-enhanced 1-13C-pyruvate-d3, which is rapidly enhanced via para-hydrogen, and thus, the signal is amplified by several orders of magnitudes in less than a minute. Using as a model, human melanoma xenografts injected with signal-enhanced 1-13C-pyruvate-d3, we show that the conversion of pyruvate into lactate can be monitored along with its kinetics, which could pave the way for rapidly detecting and monitoring changes in tumor metabolism. 相似文献
125.
Donglin Xia Jia Li Lingzi Feng Ziqing Gao Jun Liu Xiangqian Wang Yong Hu 《Macromolecular bioscience》2023,23(12):2300178
Chemotherapy drugs continue to be the main component of oncology treatment research and have been proven to be the main treatment modality in tumor therapy. However, the poor delivery efficiency of cancer therapeutic drugs and their potential off-target toxicity significantly limit their effectiveness and extensive application. The recent integration of biological carriers and functional agents is expected to camouflage synthetic biomimetic nanoparticles for targeted delivery. The promising candidates, including but not limited to red blood cells and their membranes, platelets, tumor cell membrane, bacteria, immune cell membrane, and hybrid membrane are typical representatives of biological carriers because of their excellent biocompatibility and biodegradability. Biological carriers are widely used to deliver chemotherapy drugs to improve the effectiveness of drug delivery and therapeutic efficacy in vivo, and tremendous progress is made in this field. This review summarizes recent developments in biological vectors as targeted drug delivery systems based on microenvironmental stimuli-responsive release, thus highlighting the potential applications of target drug biological carriers. The review also discusses the possibility of clinical translation, as well as the exploitation trend of these target drug biological carriers. 相似文献
126.
取扬州市中医院2010年1月-2013年12月住院治疗的肺癌患者,共425例,对照组为同期来院体检或探视病人的家属,共425例,采用自行设计的问卷进行调查,并使用Logistic回归分析来进行统计,分析扬州市肺癌病人发病的风险因素。结果表明,肺部疾病对肺癌发病率的影响最大,然后依次是内向忧郁的不良情绪,吸烟因素,患有高血压疾病;经常食用新鲜蔬菜瓜果则是肺癌的保护性因素.给出建议:应培养乐观积极的心态,大力提倡健康的生活方式,多吃新鲜蔬果,适当进行一些体育锻炼,加强控烟力度,防治慢性病. 相似文献
127.
Human ADAMs (a disintegrin and metalloproteinases) have been established as an attractive therapeutic target of inflammatory disorders such as inflammatory bowel disease (IBD). The ADAM metallopeptidase domain 17 (ADAM17 or TACE) and its close relative ADAM10 are two of the most important ADAM members that share high conservation in sequence, structure and function, but exhibit subtle difference in regulation of downstream cell signaling events. Here, we described a systematic protocol that combined computational modeling and experimental assay to discover novel peptide hydroxamate derivatives as potent and selective inhibitors for ADAM17 over ADAM10. In the procedure, a virtual combinatorial library of peptide hydroxamate compounds was generated by exploiting intermolecular interactions involved in crystal and modeled structures. The library was examined in detail to identify few promising candidates with both high affinity to ADAM17 and low affinity to ADAM10, which were then tested in vitro with enzyme inhibition assay. Consequently, two peptide hydroxamates Hxm-Phe-Ser-Asn and Hxm-Phe-Arg-Gln were found to exhibit potent inhibition against ADAM17 (Ki = 92 and 47 nM, respectively) and strong selectivity for ADAM17 over ADAM10 (∼7-fold and ∼5-fold, S = 0.86 and 0.71, respectively). The structural basis and energetic property of ADAM17 and ADAM10 interactions with the designed inhibitors were also investigated systematically. It is found that the exquisite network of nonbonded interactions involving the side chains of peptide hydroxamates is primarily responsible for inhibitor selectivity, while the coordination interactions and hydrogen bonds formed by the hydroxamate moiety and backbone of peptide hydroxamates confer high affinity to inhibitor binding. 相似文献
128.
肿瘤细胞中长春新碱的高效液相色谱法测定 总被引:10,自引:0,他引:10
长春新碱(VCR)为重要和常用抗肿瘤药物之一。肿瘤细胞耐药性是导致化疗失败的主要原因。为了筛选耐药细胞的逆转剂,建立了测定肿瘤细胞内VCR浓度的高效液相色谱法,色谱条件为:Zorbax-ODS反相柱25cm×4.6mmi.d.,流动相:0.02mol/LK2HPO4(pH6.6)∶CH3OH(20∶80,V/V),流速:1.0mL/min,检测波长:267nm。方法简单、快速、选择性好,在10~200mg/L范围内VCR浓度-峰高呈良好的线性关系(r=0.9998),仪器灵敏度为4ng。 相似文献
129.
In this study, we thoroughly analyzed molecular gradient generation, its stability over time, and linearity in our high-throughput drug screening microfluidic assay (HTS). These parameters greatly affect the precision and accuracy of the device’s analytical protocol. As part of the research, we developed a mathematical model of dependence of the concentration profile on the initial concentrations of active substances in reservoirs and the number of tilts, as well as the dependence of the active substance concentration profiles in the culture chambers on the concentration profile of the reference dye in the indicator chamber. The mean concentration prediction error of the proposed equations ranged from 1.4% to 2.4% for the optimized parameters of the procedure and did not increase with the incubation time. The concentration profile linearity index, Pearson’s correlation coefficient reached −0.997 for 25 device tilts. The observed time stability of the profiles was very good. The mean difference between the concentration profile after 5 days of incubation and the baseline profile was only 7.0%. The newly created mathematical relationships became part of the new HTS biochip operating protocols, which are detailed in the article. 相似文献
130.
Fernanda Bueno Morrone Pedro Vargas Liliana Rockenbach Thamiris Becker Scheffel 《Molecules (Basel, Switzerland)》2021,26(20)
Gliomas are the most common malignant brain tumors in adults, characterized by a high proliferation and invasion. The tumor microenvironment is rich in growth-promoting signals and immunomodulatory pathways, which increase the tumor’s aggressiveness. In response to hypoxia and glioma therapy, the amounts of adenosine triphosphate (ATP) and adenosine diphosphate (ADP) strongly increase in the extracellular space, and the purinergic signaling is triggered by nucleotides’ interaction in P2 receptors. Several cell types are present in the tumor microenvironment and can facilitate tumor growth. In fact, tumor cells can activate platelets by the ADP-P2Y12 engagement, which plays an essential role in the cancer context, protecting tumors from the immune attack and providing molecules that contribute to the growth and maintenance of a rich environment to sustain the protumor cycle. Besides platelets, the P2Y12 receptor is expressed by some tumors, such as renal carcinoma, colon carcinoma, and gliomas, being related to tumor progression. In this context, this review aims to depict the glioma microenvironment, focusing on the relationship between platelets and tumor malignancy. 相似文献