全文获取类型
收费全文 | 3127篇 |
免费 | 100篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 29篇 |
综合类 | 5篇 |
化学工业 | 1127篇 |
金属工艺 | 47篇 |
机械仪表 | 54篇 |
建筑科学 | 233篇 |
矿业工程 | 8篇 |
能源动力 | 76篇 |
轻工业 | 271篇 |
水利工程 | 17篇 |
石油天然气 | 3篇 |
武器工业 | 4篇 |
无线电 | 176篇 |
一般工业技术 | 440篇 |
冶金工业 | 305篇 |
原子能技术 | 41篇 |
自动化技术 | 395篇 |
出版年
2022年 | 30篇 |
2021年 | 66篇 |
2020年 | 34篇 |
2019年 | 33篇 |
2018年 | 44篇 |
2017年 | 34篇 |
2016年 | 76篇 |
2015年 | 69篇 |
2014年 | 74篇 |
2013年 | 151篇 |
2012年 | 108篇 |
2011年 | 149篇 |
2010年 | 125篇 |
2009年 | 131篇 |
2008年 | 127篇 |
2007年 | 119篇 |
2006年 | 114篇 |
2005年 | 106篇 |
2004年 | 80篇 |
2003年 | 57篇 |
2002年 | 72篇 |
2001年 | 59篇 |
2000年 | 62篇 |
1999年 | 79篇 |
1998年 | 99篇 |
1997年 | 90篇 |
1996年 | 73篇 |
1995年 | 67篇 |
1994年 | 56篇 |
1993年 | 42篇 |
1992年 | 58篇 |
1991年 | 52篇 |
1990年 | 38篇 |
1989年 | 47篇 |
1988年 | 34篇 |
1987年 | 37篇 |
1986年 | 38篇 |
1985年 | 36篇 |
1984年 | 36篇 |
1983年 | 30篇 |
1982年 | 26篇 |
1981年 | 33篇 |
1980年 | 25篇 |
1979年 | 23篇 |
1978年 | 27篇 |
1977年 | 39篇 |
1976年 | 39篇 |
1975年 | 26篇 |
1974年 | 25篇 |
1973年 | 22篇 |
排序方式: 共有3231条查询结果,搜索用时 31 毫秒
1.
2.
Lissy Z. F. Gross Mariana Sacerdoti Prof. Albrecht Piiper Prof. Stefan Zeuzem Dr. Alejandro E. Leroux Dr. Ricardo M. Biondi 《ChemMedChem》2020,15(18):1682-1690
Angiotensin converting enzyme 2 (ACE2) is the human receptor that interacts with the spike protein of coronaviruses, including the one that produced the 2020 coronavirus pandemic (COVID-19). Thus, ACE2 is a potential target for drugs that disrupt the interaction of human cells with SARS-CoV-2 to abolish infection. There is also interest in drugs that inhibit or activate ACE2, that is, for cardiovascular disorders or colitis. Compounds binding at alternative sites could allosterically affect the interaction with the spike protein. Herein, we review biochemical, chemical biology, and structural information on ACE2, including the recent cryoEM structures of full-length ACE2. We conclude that ACE2 is very dynamic and that allosteric drugs could be developed to target ACE2. At the time of the 2020 pandemic, we suggest that available ACE2 inhibitors or activators in advanced development should be tested for their ability to allosterically displace the interaction between ACE2 and the spike protein. 相似文献
3.
Steffen Vojacek Lukas Schulig Nathalie Wössner Norman Geist Prof. Dr. Walter Langel Prof. Dr. Manfred Jung Prof. Dr. Dennis Schade Prof. Dr. Andreas Link 《ChemMedChem》2019,14(8):853-864
Indoles are privileged structures in medicinal and bioorganic chemistry that are particularly well suited to serve as platforms for diversity. Among many other therapeutic areas, the indole scaffold has been used to design aromatic compounds useful to interfere with enzymes engaged in the regulation of substrate acylation status, such as sirtuins. However, the planarity of the indole ring is not necessarily optimal for all target enzymes, especially when functionalization with aromatic side chains is required. Replacement of flat scaffolds by nonplanar molecular cores dominated by sp3 hybridization is a common strategy to avoid the disadvantages associated with poor solubility and high promiscuity, while covering less-well-explored areas of chemical space. Thus, we synthesized fragment-like tetrahydroindoles suitable for fragment-based drug discovery as well as a well-characterized small library intended as multipurpose screening compounds. For proof of principle, these compounds were screened against sirtuins 1–3, enzymes known to be addressable by indoles. We found that 2,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indole-3-carboxamides are potent and selective SIRT2 inhibitors. Compound 16 t displayed an IC50 value of 0.98 μm and could serve as exquisite starting point for hit-to-lead profiling. 相似文献
4.
Dr. Li Di Prof. Per Artursson Dr. Alex Avdeef Prof. Leslie Z. Benet Prof. J. Brian Houston Dr. Manfred Kansy Edward H. Kerns Prof. Hans Lennernäs Dr. Dennis A. Smith Prof. Kiyohiko Sugano 《ChemMedChem》2020,15(20):1862-1874
Passive permeability is a key property in drug disposition and delivery. It is critical for gastrointestinal absorption, brain penetration, renal reabsorption, defining clearance mechanisms and drug-drug interactions. Passive diffusion rate is translatable across tissues and animal species, while the extent of absorption is dependent on drug properties, as well as in vivo physiology/pathophysiology. Design principles have been developed to guide medicinal chemistry to enhance absorption, which combine the balance of aqueous solubility, permeability and the sometimes unfavorable compound characteristic demanded by the target. Permeability assays have been implemented that enable rapid development of structure-permeability relationships for absorption improvement. Future advances in assay development to reduce nonspecific binding and improve mass balance will enable more accurately measurement of passive permeability. Design principles that integrate potency, selectivity, passive permeability and other ADMET properties facilitate rapid advancement of successful drug candidates to patients. 相似文献
5.
Diese Recherche zeigt, dass sich die Bedeutung, die dem Thema RFID in den Medien und der ?ffentlichen Diskussion derzeit beigemessen
wird, auch in der Anzahl der im Internet zu findenden Seiten niederschl?gt. Dabei bewegt sich die Qualit?t der betrachteten
Angebote überwiegend auf einem hohen Niveau, was vor allem auf Seiten der kommerziellen Anbieter nicht weiter verwundert,
da es sich bei RFID doch um einen zunehmend st?rker umk?mpften Markt handelt, auf dem es hei?t, potenzielle Kunden für sich
zu akquirieren. Es darf mit Spannung erwartet werden, wie sich das Informationsangebot wandelt, wenn tats?chlich das prognostizierte
exponentielle Wachstum des RFID-Marktes eintritt. 相似文献
6.
Albrecht Jason E.; O'Brien Edward J.; Mason Robert A.; Myers Jerome L. 《Canadian Metallurgical Quarterly》1995,21(2):364
An implicit assumption of several causal reasoning models is that readers adopt the goals of a narrative's protagonist during text comprehension. In apparent violation of this assumption, readers participating in Experiment 1 of the present study drew inferences relevant to a protagonist's goal even when that goal was already satisfied from the perspective of the protagonist. In Experiments 2 and 3, participants were explicitly asked to view the text situation from the point of view of the protagonist. In this case, the goals of the reader and the protagonist should be the same. In these experiments, participants focused on the goals of the protagonist only when those goals had not been satisfied from the perspective of the protagonist. These results are discussed in terms of reader- and character-based perspectives and in terms of text characteristics that cue perspective taking. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
The curing of diglycidyl ether of bisphenol A (DGEBA) with 2,6-dimethylol-p-cresol modified by hexahydrophthalic acid anhydride was investigated and compared with the analogous in situ curing of DGEBA, hexahydrophthalic acid anhydride and 2,6-dimethylol-p-cresol. The chemical reactions were investigated by means of titration and different spectroscopic and chromatographic methods. It was examined whether the less complicated and therefore cheaper in situ reaction delivers postcured products with equal or better properties. Furthermore, it was investigated whether the results are similar using technical phenolic hardeners. 相似文献
8.
Ubiquitin has been shown by immunohistochemical studies to be a component of many of the filamentous inclusion bodies that are known in neuropathology. In the current study, we examined the expression of ubiquitin in 14 cases of typical inclusion body myositis, in skeletal muscle specimens from four cases of typical amyotrophic lateral sclerosis, and in muscle specimens from three normal controls. In the cases of inclusion body myositis, rimmed vacuoles were ubiquitin immunoreactive in all cases. Intrasarcoplasmic inclusions were positive in the nine cases that had them. In four cases, there were positive intranuclear inclusions, and in seven, there was homogeneous staining of nuclei. Atrophic fibers and necrotic fibers were positive in 11 and nine cases, respectively. In the cases of amyotrophic lateral sclerosis, atrophic fibers were positive in three cases, and focal nuclear staining was seen in two. In one of the three control cases, a few atrophic fibers had faint sarcoplasmic positivity; no other staining was seen. We conclude that ubiquitin is a component of the inclusions that characterize inclusion body myositis. However, ubiquitin expression in skeletal muscle disease is not pathognomonic of inclusion body myositis. 相似文献
9.
10.