全文获取类型
收费全文 | 1363篇 |
免费 | 32篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 184篇 |
金属工艺 | 14篇 |
机械仪表 | 16篇 |
建筑科学 | 55篇 |
矿业工程 | 1篇 |
能源动力 | 18篇 |
轻工业 | 148篇 |
水利工程 | 7篇 |
石油天然气 | 3篇 |
无线电 | 59篇 |
一般工业技术 | 156篇 |
冶金工业 | 610篇 |
原子能技术 | 17篇 |
自动化技术 | 105篇 |
出版年
2021年 | 5篇 |
2020年 | 12篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 19篇 |
2016年 | 19篇 |
2015年 | 16篇 |
2014年 | 20篇 |
2013年 | 73篇 |
2012年 | 37篇 |
2011年 | 66篇 |
2010年 | 42篇 |
2009年 | 42篇 |
2008年 | 61篇 |
2007年 | 58篇 |
2006年 | 57篇 |
2005年 | 49篇 |
2004年 | 24篇 |
2003年 | 39篇 |
2002年 | 35篇 |
2001年 | 27篇 |
2000年 | 26篇 |
1999年 | 21篇 |
1998年 | 69篇 |
1997年 | 35篇 |
1996年 | 49篇 |
1995年 | 29篇 |
1994年 | 33篇 |
1993年 | 28篇 |
1992年 | 16篇 |
1991年 | 19篇 |
1990年 | 28篇 |
1989年 | 26篇 |
1988年 | 21篇 |
1987年 | 28篇 |
1986年 | 23篇 |
1985年 | 27篇 |
1984年 | 18篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 20篇 |
1978年 | 20篇 |
1977年 | 18篇 |
1976年 | 14篇 |
1975年 | 9篇 |
1974年 | 6篇 |
1973年 | 10篇 |
1972年 | 9篇 |
排序方式: 共有1396条查询结果,搜索用时 15 毫秒
1.
Cover Feature: Nucleoside‐Based Self‐Assembling Drugs for Localized Drug Delivery (ChemMedChem 11/2018) 下载免费PDF全文
2.
Jongwoo Kim Eun Hee Park Young Soon Park Kyung Hee Chun Lynn L. Wiles 《Information Systems Journal》2022,32(1):164-191
Regulations, such as the Health Insurance Portability and Accountability Act (HIPAA), establish standards to protect patients' medical records from security breaches. Insiders' prosocial misbehaviour within healthcare organisations can cause significant damage to relevant stakeholders. Such behaviour without malicious intention needs to be better understood and carefully managed from the perspective of prosocial behaviour. For this study, a research model was developed that includes the factors influencing student nurses' intention to disclose patient health information. The model was empirically tested with nursing students in South Korea with a scenario-based experiment. We find that both altruistic (impact on others) and egoistic (impact on the self) motivations are significantly important in raising situational empathy. On the other hand, an egoistic motivation (impact on the self) significantly affects people's perception of their responsibility, which mediates the relationship between situational empathy and prosocial intention to disclose. The implications of our findings are discussed. 相似文献
3.
Biochemical,Structural, and Genetic Characterization of Tridecaptin A1, an Antagonist of Campylobacter jejuni 下载免费PDF全文
Christopher T. Lohans Dr. Marco J. van Belkum Stephen A. Cochrane Dr. Zedu Huang Dr. Clarissa S. Sit Prof. Lynn M. McMullen Prof. John C. Vederas 《Chembiochem : a European journal of chemical biology》2014,15(2):243-249
Bacillus circulans NRRL B‐30644 (now Paenibacillus terrae) was previously reported to produce SRCAM 1580, a bacteriocin active against the food pathogen Campylobacter jejuni. We have been unable to isolate SRCAM 1580, and did not find any genetic determinants in the genome of this strain. We now report the reassignment of this activity to the lipopeptide tridecaptin A1. Structural characterization of tridecaptin A1 was achieved through NMR, MS/MS and GC‐MS studies. The structure was confirmed through the first chemical synthesis of tridecaptin A1, which also revealed the stereochemistry of the lipid chain. The impact of this stereochemistry on antimicrobial activity was examined. The biosynthetic machinery responsible for tridecaptin production was identified through bioinformatic analyses. P. terrae NRRL B‐30644 also produces paenicidin B, a novel lantibiotic active against Gram‐positive bacteria. MS/MS analyses indicate that this lantibiotic is structurally similar to paenicidin A. 相似文献
4.
In a series of papers Andrew Oswald has suggested that since home owners are relatively less mobile across geographic locations than renters, regional home ownership rates are positively correlated with regional unemployment rates. This paper examines this hypothesis at the individual level. Search theory suggests that when a subset of the population is less mobile than others, this less mobile group (that is, owners) will have lower probability of employment, longer spells of unemployment and lower wages than more mobile renters. These hypotheses on inferior labour market outcomes for owners were tested using US Current Population Survey data as well as data from the Panel Survey of Income Dynamics. The empirical model suggests that these hypotheses are not supported by any of the tests. Home owners, conditionally or unconditionally, have better labour market outcomes than renters. 相似文献
5.
Three mixed-culture nitrifier sources degraded low concentrations (25-450 microg/L) of four trihalomethanes (THMs) (trichloromethane (TCM) or chloroform, bromodichloromethane (BDCM), dibromochloromethane (DBCM), tribromomethane (TBM) or bromoform) commonly found in treated drinking water. Individual THM rate constants (k1THM) increased with increasing THM bromine-substitution with TBM>DBCM>BDCM>TCM and were comparable to previous studies with the pure culture nitrifier, Nitrosomonas europaea. A decrease in temperature resulted in a decrease in both ammonia and THM degradation rates with ammonia rates affected to a greater extent than THM degradation rates. The significant effect of temperature indicates that seasonal variations in water temperature should be a consideration for technology implementation. Product toxicity, measured by transformation capacity (T(c)), was similar to that observed with N. europaea. Because both rate constants and product toxicities increase with increasing THM bromine-substitution, a water's THM speciation is an important consideration for process implementation during drinking water treatment. Even though a given water is kinetically favored, the resulting THM product toxicity may not allow stable treatment process performance. 相似文献
6.
7.
Blake N. Johnson Karen Z. Lancaster Gehua Zhen Junyun He Maneesh K. Gupta Yong Lin Kong Esteban A. Engel Kellin D. Krick Alex Ju Fanben Meng Lynn W. Enquist Xiaofeng Jia Michael C. McAlpine 《Advanced functional materials》2015,25(39):6205-6217
A 3D printing methodology for the design, optimization, and fabrication of a custom nerve repair technology for the regeneration of complex peripheral nerve injuries containing bifurcating sensory and motor nerve pathways is introduced. The custom scaffolds are deterministically fabricated via a microextrusion printing principle using 3D models, which are reverse engineered from patient anatomies by 3D scanning. The bifurcating pathways are augmented with 3D printed biomimetic physical cues (microgrooves) and path‐specific biochemical cues (spatially controlled multicomponent gradients). In vitro studies reveal that 3D printed physical and biochemical cues provide axonal guidance and chemotractant/chemokinetic functionality. In vivo studies examining the regeneration of bifurcated injuries across a 10 mm complex nerve gap in rats showed that the 3D printed scaffolds achieved successful regeneration of complex nerve injuries, resulting in enhanced functional return of the regenerated nerve. This approach suggests the potential of 3D printing toward advancing tissue regeneration in terms of: (1) the customization of scaffold geometries to match inherent tissue anatomies; (2) the integration of biomanufacturing approaches with computational modeling for design, analysis, and optimization; and (3) the enhancement of device properties with spatially controlled physical and biochemical functionalities, all enabled by the same 3D printing process. 相似文献
8.
9.
10.
J. Maxwell Dow Lynn M. Naughton Birte Hollmann Shi-Qi An Robert P. Ryan 《Israel journal of chemistry》2016,56(5):321-329
Bacterial cell-to-cell signals of the diffusible signal factor (DSF) family are cis-2-unsaturated fatty acids that differ in their chain length and branching patterns. Signaling involving DSF family members occurs in diverse bacteria to include plant and human pathogens. In the majority of these organisms, the perception of DSF is linked to turnover of the second messenger cyclic di-GMP by one of two “core” pathways. Additional “accessory” signal transduction pathways can also be found, but are not widely conserved. DSF signaling acts to regulate diverse functions to include biofilm formation and architecture, antibiotic resistance, and the production of virulence factors in pathogens. DSF family signals can also participate in interspecies signaling with other bacteria and interkingdom signaling with the yeast Candida albicans. Such interactions may have importance in modifying microbial behavior during polymicrobial infections. 相似文献