全文获取类型
收费全文 | 728篇 |
免费 | 39篇 |
学科分类
工业技术 | 767篇 |
出版年
2023年 | 10篇 |
2022年 | 9篇 |
2021年 | 31篇 |
2020年 | 22篇 |
2019年 | 25篇 |
2018年 | 24篇 |
2017年 | 28篇 |
2016年 | 25篇 |
2015年 | 15篇 |
2014年 | 17篇 |
2013年 | 30篇 |
2012年 | 31篇 |
2011年 | 48篇 |
2010年 | 35篇 |
2009年 | 31篇 |
2008年 | 27篇 |
2007年 | 29篇 |
2006年 | 20篇 |
2005年 | 16篇 |
2004年 | 11篇 |
2003年 | 16篇 |
2002年 | 11篇 |
2001年 | 11篇 |
2000年 | 10篇 |
1999年 | 6篇 |
1998年 | 37篇 |
1997年 | 20篇 |
1996年 | 11篇 |
1995年 | 19篇 |
1994年 | 17篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 11篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1971年 | 2篇 |
排序方式: 共有767条查询结果,搜索用时 31 毫秒
91.
A workable psychology of individuality is "one that would generate good research ideas, which, in turn, would lead to steady increases in dependable knowledge." Individual uniqueness "is described primarily in terms of choice and organization, and I consider it the task of psychologists to make those concepts workable—to bring them into the general stream of thinking in research, assessment, and practical activities." Tyler stresses "the significance of concepts of choice and organization in an inclusive psychology of the development of the human individual… . At each stage of our lives, we impose limits on the next stage, by the choices we make and the ways in which we organize what we have experienced." (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
92.
93.
M. G. O'Reilly P. O. Olomolaiye A. H. Tyler T. Orr 《Building Research & Information》1994,22(5):247-251
A useful review of issues of health and safety linked to legislation, as well as highlighting the most serious types of accidents identified in the survey. 相似文献
94.
Form factors are used in radiosity image synthesis to describe the fraction of diffusely reflected light leaving one surface and reaching another. They incorporate fundamental geometric properties of interacting surfaces used for light transfer computation.Many numerical applications such as realistic image synthesis require accurate and simple formula for the form factors from small oriented differential areas (treated as a point with a normal) to different geometrical objects; a disk was used in this paper. The exact analytic solution for the general point-to-disk form factor integral is used to develop more accurate numerical techniques for form factor integration for surfaces commonly in use. The improvements are illustrated with realistic image synthesis. 相似文献
95.
Non-stoichiometry, induced by exposure to oxygen and vacuum has been investigated for the uranium oxides UO2, U4O9 and U3O8 using X-ray photoelectron spectroscopy. Each stoichiometric uranium oxide is shown to display a unique X-ray photoelectron spectrum which can be altered quite dramatically by changes in stoichiometry and explained by a defect cluster model. 相似文献
96.
Recent research has suggested that the shell of an air-entrained void is important for resisting coalescence between air-voids and diffusion of gas from the surrounding fluid. The current paper describes the physical and chemical properties of an air-void shell during the first 2 h of hydration and chemical characteristics at 60 days. Results from this research suggest that the air-void shells found in air-entrained paste have varied physical properties and the crystalline material of these shells is largely made up of fine cement particles during the first 2 h of hydration. Observations of paste at 60 days of hydration suggest that the shell is made up of calcium silicate hydrate (C-S-H) with a morphology different from that in the bulk paste. 相似文献
97.
98.
Tyler Maher 《Critical reviews in food science and nutrition》2019,59(10):1619-1644
Dietary fat has been implicated in the rise of obesity due to its energy density, palatability and weak effects on satiety. As fat is a major contributor to overall energy intake, incorporating fat with satiating properties could potentially reduce energy intake. This review outlines the potential mechanisms, as far as we know, by which Medium-Chain Triglycerides (MCT), Conjugated Linoleic Acid (CLA), Short-Chain Fatty Acids (SCFA), Diacylglycerol (DAG), n-3 PUFA, and Small Particle Lipids, exerts their satiating effects. The evidence suggests that the lipid with the most potential to enhance satiety is MCT. SCFA can also promote satiety, but oral administration has been linked to poor tolerability rather than satiety. Data on the appetite effects of CLA is limited but does suggest potential. Research comparing these lipids to each other is also lacking and should be explored to elucidate which of these ‘functional lipids’ is the most beneficial in enhancing satiety. 相似文献
99.
Moffett KB Tyler SW Torgersen T Menon M Selker JS Gorelick SM 《Environmental science & technology》2008,42(3):671-676
Spatially and temporally continuous temperature measurements were collected over 32 h using a fiber-optic distributed temperature sensing (DTS) system deployed along 330 m of two intertidal saltmarsh channel beds in northern California. Measured temperature gradients imparted ecosystem-scale structure to the saltmarsh tidal channel thermal regime, which was punctuated by potential warm and cold refugia. Anomalous bed temperatures of 2-4 degrees C occurred throughout the 1.3 tidal cycles at some locations. Discrete locations of consistently warm temperatures characterized sustained seepage of recently infiltrated tidal waters. Low-variance temperature anomalies were typically collocated with hidden microtopographic tributaries that facilitated mixing of warm surface waters and cold groundwater. Bed temperature gradients (approximately 2 degrees C/100 m, average) decreased from high temperatures similar to bay water at the channel mouths to low inland temperatures comparable to groundwater. The trends were maintained by cold groundwater discharge throughout the channels, which affected bed temperatures in proportion to channel reach exposure time; the opposing effect, conductive bed-warming by tidal waters, was proportional to flood duration. DTS is a promising tool for identifying spatial and temporal temperature patterns of hydroecological importance amidst complex natural systems. 相似文献
100.
Corey R. Nelson Tyler Mrozowich Sean M. Park Simmone Dsouza Amy Henrickson Justin R. J. Vigar Hans-Joachim Wieden Raymond J. Owens Borries Demeler Trushar R. Patel 《International journal of molecular sciences》2021,22(1)
Rift Valley fever virus (RVFV) is a mosquito-transmitted virus from the Bunyaviridae family that causes high rates of mortality and morbidity in humans and ruminant animals. Previous studies indicated that DEAD-box helicase 17 (DDX17) restricts RVFV replication by recognizing two primary non-coding RNAs in the S-segment of the genome: the intergenic region (IGR) and 5′ non-coding region (NCR). However, we lack molecular insights into the direct binding of DDX17 with RVFV non-coding RNAs and information on the unwinding of both non-coding RNAs by DDX17. Therefore, we performed an extensive biophysical analysis of the DDX17 helicase domain (DDX17135–555) and RVFV non-coding RNAs, IGR and 5’ NCR. The homogeneity studies using analytical ultracentrifugation indicated that DDX17135–555, IGR, and 5’ NCR are pure. Next, we performed small-angle X-ray scattering (SAXS) experiments, which suggested that DDX17 and both RNAs are homogenous as well. SAXS analysis also demonstrated that DDX17 is globular to an extent, whereas the RNAs adopt an extended conformation in solution. Subsequently, microscale thermophoresis (MST) experiments were performed to investigate the direct binding of DDX17 to the non-coding RNAs. The MST experiments demonstrated that DDX17 binds with the IGR and 5’ NCR with a dissociation constant of 5.77 ± 0.15 µM and 9.85 ± 0.11 µM, respectively. As DDX17135–555 is an RNA helicase, we next determined if it could unwind IGR and NCR. We developed a helicase assay using MST and fluorescently-labeled oligos, which suggested DDX17135–555 can unwind both RNAs. Overall, our study provides direct evidence of DDX17135–555 interacting with and unwinding RVFV non-coding regions. 相似文献