全文获取类型
收费全文 | 915篇 |
免费 | 70篇 |
国内免费 | 70篇 |
专业分类
电工技术 | 2篇 |
综合类 | 24篇 |
化学工业 | 414篇 |
金属工艺 | 56篇 |
机械仪表 | 54篇 |
建筑科学 | 20篇 |
能源动力 | 1篇 |
轻工业 | 229篇 |
石油天然气 | 5篇 |
无线电 | 24篇 |
一般工业技术 | 118篇 |
冶金工业 | 63篇 |
原子能技术 | 15篇 |
自动化技术 | 30篇 |
出版年
2024年 | 14篇 |
2023年 | 30篇 |
2022年 | 96篇 |
2021年 | 115篇 |
2020年 | 53篇 |
2019年 | 48篇 |
2018年 | 43篇 |
2017年 | 36篇 |
2016年 | 51篇 |
2015年 | 38篇 |
2014年 | 51篇 |
2013年 | 67篇 |
2012年 | 57篇 |
2011年 | 48篇 |
2010年 | 30篇 |
2009年 | 44篇 |
2008年 | 38篇 |
2007年 | 29篇 |
2006年 | 34篇 |
2005年 | 24篇 |
2004年 | 16篇 |
2003年 | 17篇 |
2002年 | 11篇 |
2001年 | 20篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1961年 | 2篇 |
排序方式: 共有1055条查询结果,搜索用时 15 毫秒
71.
Preparation and evaluation of chitosan/β‐cyclodextrin magnetic nanoparticles as a photodegradable and hydrophobic drug delivery carrier 下载免费PDF全文
In this study, novel tumor targeting nanocarriers comprised of chitosan (CS)/β‐cyclodextrin (β‐CD) magnetic nanoparticles were prepared to improve the photodegradable stability and bioavailability of hydrophobic drug. Resveratrol (Res) with photodegradable and hydrophobic properties was selected as a model drug. The photodegradation rate of Res in Fe3O4 nanoparticles solution was 7.8 times lower than that in the ethanol solution. In addition, the value of the saturation magnetization of CS/β‐CD nanoparticles was found to be 19.56 emu/g with characteristic of superparamagnetism. Approximately 90% Res was entrapped into the CS/β‐CD magnetic nanoparticles with the size distribution ranging from 200 to 359 nm, and the nanoparticles were spherical in shape with high zeta potentials. Furthermore, the formation of CS/β‐CD nanoparticles showed a sustained release in vitro. These results indicated that the obtained CS/β‐CD magnetic nanoparticles were a promising magnetic targeting carrier for photodegradable and hydrophobic drugs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45076. 相似文献
72.
73.
Barbara Fruci Stefania Giuliano Angela Mazza Roberta Malaguarnera Antonino Belfiore 《International journal of molecular sciences》2013,14(11):22933-22966
Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder worldwide. Several lines of evidence have indicated a pathogenic role of insulin resistance, and a strong association with type 2 diabetes (T2MD) and metabolic syndrome. Importantly, NAFLD appears to enhance the risk for T2MD, as well as worsen glycemic control and cardiovascular disease in diabetic patients. In turn, T2MD may promote NAFLD progression. The opportunity to take into account NAFLD in T2MD prevention and care has stimulated several clinical studies in which antidiabetic drugs, such as metformin, thiazolidinediones, GLP-1 analogues and DPP-4 inhibitors have been evaluated in NAFLD patients. In this review, we provide an overview of preclinical and clinical evidences on the possible efficacy of antidiabetic drugs in NAFLD treatment. Overall, available data suggest that metformin has beneficial effects on body weight reduction and metabolic parameters, with uncertain effects on liver histology, while pioglitazone may improve liver histology. Few data, mostly preclinical, are available on DPP4 inhibitors and GLP-1 analogues. The heterogeneity of these studies and the small number of patients do not allow for firm conclusions about treatment guidelines, and further randomized, controlled studies are needed. 相似文献
74.
Joseph Larkin Spencer Carson Daniel H. Stoloff Meni Wanunu 《Israel journal of chemistry》2013,53(6-7):431-441
Nucleic acids are central figures in many of life’s key molecular processes, e.g., enzymatic activity, epigenetics/gene regulation, viral replication, aging, cancer, and other diseases. Over the past two decades, nanopores have emerged as a new tool for studying the properties of nucleic acids at the single-molecule level. In this review, we summarize the use of nanopores as sensors of nucleic acid structure, particularly for studying chemically modified and damaged DNA, and for probing the interactions of small-molecule drugs with nucleic acid targets. 相似文献
75.
One of the strategies in the search for safe and effective analgesic drugs is the design of multitarget analgesics. Such compounds are intended to have high affinity and activity at more than one molecular target involved in pain modulation. In the present contribution we summarize the attempts in which fentanyl or its substructures were used as a μ-opioid receptor pharmacophoric fragment and a scaffold to which fragments related to non-opioid receptors were attached. The non-opioid ‘second’ targets included proteins as diverse as imidazoline I2 binding sites, CB1 cannabinoid receptor, NK1 tachykinin receptor, D2 dopamine receptor, cyclooxygenases, fatty acid amide hydrolase and monoacylglycerol lipase and σ1 receptor. Reviewing the individual attempts, we outline the chemistry, the obtained pharmacological properties and structure-activity relationships. Finally, we discuss the possible directions for future work. 相似文献
76.
77.
创新药物产业化的研究与探讨 总被引:1,自引:0,他引:1
创新是生存和发展的动力,医药产业的发展同样也离不开不断的创新。医药产业巨大的经济效益在未来注定依赖创新药物产业化的发展和完善。将围绕中国创新药物产业化展开。从创新药物的研发过程,研究管理以及产业化的市场策略等方面,对我国医药产业中创新药物的发展方向给出建设性意见,为医药产业的健康,快速发展提供了一条可行的道路。 相似文献
78.
对外消旋体药物进行分离拆分是获取手性药物的重要方法。探讨了环糊精体系包结拆分法的机理,并对运用其机理于手性药物分离中的应用作了探讨。 相似文献
79.
Koch AM Reynolds F Merkle HP Weissleder R Josephson L 《Chembiochem : a European journal of chemical biology》2005,6(2):337-345
We synthesized three peptides, a D-polyarginyl peptide (r8(FITC)), a Tat peptide (Tat(FITC)), and a control peptide (Cp(FITC)) and attached each to amino-CLIO, a nanoparticle 30 nm in diameter. We then examined the effective permeability, Peff, of all six materials through CaCo-2 monolayers. The transport of peptide-nanoparticles was characterized by a lag phase (0-8 h) and a steady-state phase (9-27 h). The steady-state Peff values for peptides were in the order r8(FITC)>Tat(FITC)=Cp(FITC). When r8(FITC) and Tat(FITC) peptides were attached to the nanoparticle, they conferred their propensity to traverse cell monolayers onto the nanoparticle, whereas Cp(FITC) did not. Thus, when the r8(FITC) peptide was attached to the amino-CLIO nanoparticle, the resulting peptide-nanoparticle had a Peff similar to that of this poly-D-arginyl peptide alone. The Peff of r8(FITC)-CLIO (MW approximately 1000 kDa) was similar to that of mannitol (MW=182 Da), a poorly transported reference substance, with a far lower molecular weight. These results are the first to indicate that the modification of nanoparticles by attachment of membrane-translocating sequence-based peptides can alter nanoparticle transport through monolayers. This suggests that the surface modification of nanoparticles might be a general strategy for enhancing the permeability of drugs and that high-permeability nanoparticle-based therapeutics can be useful in selected pharmaceutical applications. 相似文献
80.
Broad‐spectrum antibiotics with heterocyclic side chains strongly inhibit peroxidase‐catalyzed iodination in the presence of metallo‐β‐lactamase. This suggests that antibiotic resistance due to hydrolysis of the β‐lactam ring in antibiotics would have negative effects on thyroid activity.