全文获取类型
收费全文 | 747篇 |
免费 | 25篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 86篇 |
金属工艺 | 6篇 |
机械仪表 | 8篇 |
建筑科学 | 34篇 |
矿业工程 | 4篇 |
能源动力 | 14篇 |
轻工业 | 58篇 |
水利工程 | 6篇 |
石油天然气 | 6篇 |
无线电 | 74篇 |
一般工业技术 | 111篇 |
冶金工业 | 223篇 |
原子能技术 | 10篇 |
自动化技术 | 126篇 |
出版年
2023年 | 10篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 21篇 |
2017年 | 11篇 |
2016年 | 7篇 |
2015年 | 18篇 |
2014年 | 14篇 |
2013年 | 39篇 |
2012年 | 18篇 |
2011年 | 22篇 |
2010年 | 26篇 |
2009年 | 26篇 |
2008年 | 23篇 |
2007年 | 26篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 14篇 |
1998年 | 46篇 |
1997年 | 23篇 |
1996年 | 28篇 |
1995年 | 18篇 |
1994年 | 22篇 |
1993年 | 16篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 17篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 11篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 10篇 |
1974年 | 6篇 |
1972年 | 5篇 |
1966年 | 6篇 |
排序方式: 共有773条查询结果,搜索用时 15 毫秒
81.
Suggests an alternative to H. H. Strupp and S. W. Hadley's (see record 1977-29884-001) tripartite model for evaluating treatment outcome, in which primary prevention, self-regulation methods are used to evaluate individuals' ability to control emotions that interfere with everyday functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
82.
83.
84.
Contends that the ideal program of research to maximize clinical relevance combines 4 models of strategies. These are (1) convergent/convergent, (2) divergent/divergent, (3) divergent-theory/convergent-method, and (4) convergent-theory/divergent-method, and all are employed nomothetically at the level of theory and idiographically at the level of method. Model 1 serves to expand theoretical and procedural possibilities, giving clinicians the flexibility they need when working with individuals in service-delivery settings. Model 2 controls theoretical expansion. Model 3 controls procedural expansion. Model 4 may be used to provide preliminary demonstrations of feasibility that are then used to stimulate other forms of more directly relevant investigation. The products of this overall program of research will increasingly represent a useful body of tested theoretical and procedural possibilities and alternatives that clinicians can use for explaining and treating individual clients and for evaluating treatment outcomes in individually relevant terms. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
85.
MM Miller HP Bennett RB Billiar KB Franklin D Joshi 《Canadian Metallurgical Quarterly》1998,33(7-8):729-757
Our studies in the C57BL/6J mouse have been designed to examine the interactions of aging and the ovary, and their mutual effects on neuroendocrine function. In the pituitary, ovarian status and not age determines responsiveness to gonadotropin hormone releasing hormone (GnRH), but estrogen (E2) is an important mediator in CNS changes, and removal of the ovary (OVX) is deleterious to the neuroendocrine hypothalamus. OVX for just six days in young animals results in synaptic loss between noradrenergic terminals and gonadotropin hormone releasing hormone (GnRH) neurons. Long-term OVX, hypothesized to protect against neuroendocrine aging, fails to guard against any studied age-related changes. Some age-related changes occur as early as midlife. Although neuron number remains constant at middle age, opiatergic neurons undergo significant functional changes by producing opiate antagonist peptides. This change appears to be caused by alterations in the prohormone convertases, which cleave propeptide to peptide. Altered peptides may trigger the loss of reproductive capacity. The midlife shift in opiate peptide production is a component of natural developmental processes that begin in the neonate and continue through old age. In the cholinergic system, E2 mediates numbers of cholinergic receptors, cholinergic neurons, and cholinergic-modulated memory systems in both young and old animals. Regardless of age, ovarian steroids, if present at physiologic levels, are beneficial to the neuroendocrine CNS, and long-term deprivation from ovarian-produced factors is deleterious in the systems we have examined. Our studies have shown that deprivation from ovarian steroid hormones in the female appears to be a major factor in the health of the CNS and in events associated with aging. 相似文献
86.
87.
Significant advancement has been made in nanoparticle research, with synthetic techniques extending over a wide range of materials with good control over particle size and shape. A grand challenge is assembling and positioning the nanoparticles in desired locations to construct complex, higher-order functional structures. Controlled positioning of nanoparticles has been achieved in pre-defined templates fabricated by top-down approaches. A self-assembly method, however, is highly desirable because of its simplicity and compatibility with heterogeneous integration processes. Here we report on the spontaneous formation of ordered gold and silver nanoparticle stripe patterns on dewetting a dilute film of polymer-coated nanoparticles floating on a water surface. Well-aligned stripe patterns with tunable orientation, thickness and periodicity at the micrometre scale were obtained by transferring nanoparticles from a floating film onto a substrate in a dip-coating fashion. This facile technique opens up a new avenue for lithography-free patterning of nanoparticle arrays for various applications including, for example, multiplexed surface-enhanced Raman substrates and templated fabrication of higher-order nanostructures. 相似文献
88.
Effects of minerals on yields of C3-C8 volatiles from rapid pyrolysis of a Pittsburgh Seam bituminous coal were investigated. Whole, demineralized, and mineral-treated samples of pulverized coal were heated in 101 kPa He or 6.99 MPaH2 at 1000 K s−1 to temperatures of up to 1300 K. Yields of C3, C4–C6, and C6–C8 hydrocarbon gases were determined as a function of time-temperature history. Calcium minerals decrease yields of all three fractions in pyrolysis under He atmosphere but have little effect on hydropyrolysis. Kaolinite reduces yields in pyrolysis, but increases them in hydropyrolysis. Other minerals, notably FeSO4, have varying effects on product yields depending on run conditions. 相似文献
89.
The introduction and rapid spread of pulse code modulation must be examined in the framework of overall capability, efficiency, and cost. However, apart from television, the only field of application that can presently justify a massive investment in a new transmission system is telephony, because it represents the dominant communication market. Other communication services?such as data and facsimile transmission, telegraphy, broadcast sound, and closed-circuit television?must in general travel as passengers on telephony networks if they are to be economically feasible. Hence, the most fruitful approach to an examination of digital communication is to begin by studying PCM telephony and then to see how other services can be coordinated with it. 相似文献
90.
A function generator for providing, in analogue, the mantissa of the logarithm of two numbers, given the logarithm of each, may be realised by the conductance of the series combination of a resistor and a semiconductor diode. Its application to a logarithmic digital/analogue convertor for serial inputs is described. 相似文献