全文获取类型
收费全文 | 2763篇 |
免费 | 64篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 67篇 |
综合类 | 8篇 |
化学工业 | 567篇 |
金属工艺 | 75篇 |
机械仪表 | 40篇 |
建筑科学 | 139篇 |
矿业工程 | 13篇 |
能源动力 | 32篇 |
轻工业 | 304篇 |
水利工程 | 11篇 |
石油天然气 | 7篇 |
无线电 | 194篇 |
一般工业技术 | 350篇 |
冶金工业 | 756篇 |
原子能技术 | 17篇 |
自动化技术 | 251篇 |
出版年
2019年 | 27篇 |
2018年 | 29篇 |
2017年 | 26篇 |
2016年 | 48篇 |
2015年 | 38篇 |
2014年 | 36篇 |
2013年 | 133篇 |
2012年 | 60篇 |
2011年 | 91篇 |
2010年 | 66篇 |
2009年 | 77篇 |
2008年 | 77篇 |
2007年 | 82篇 |
2006年 | 84篇 |
2005年 | 81篇 |
2004年 | 69篇 |
2003年 | 69篇 |
2002年 | 66篇 |
2001年 | 41篇 |
2000年 | 42篇 |
1999年 | 56篇 |
1998年 | 71篇 |
1997年 | 69篇 |
1996年 | 55篇 |
1995年 | 41篇 |
1994年 | 50篇 |
1993年 | 54篇 |
1992年 | 45篇 |
1991年 | 30篇 |
1990年 | 35篇 |
1989年 | 47篇 |
1988年 | 41篇 |
1987年 | 31篇 |
1986年 | 29篇 |
1985年 | 44篇 |
1984年 | 54篇 |
1983年 | 51篇 |
1982年 | 39篇 |
1981年 | 38篇 |
1980年 | 41篇 |
1979年 | 34篇 |
1978年 | 43篇 |
1977年 | 40篇 |
1976年 | 54篇 |
1975年 | 35篇 |
1974年 | 30篇 |
1973年 | 26篇 |
1972年 | 35篇 |
1971年 | 29篇 |
1966年 | 28篇 |
排序方式: 共有2831条查询结果,搜索用时 15 毫秒
91.
Uwe Matuschczyk Herbert Reil 《中华纸业》2005,26(4):31-32
对比了QualiFlex Q型,QualiFlex QX型、QualiFlex QV型三种聚胺酯材料靴套的性能,从而说明独特的QualiFlex靴套性能,使纸幅横幅水分的均匀性得到改善,纸幅出压榨干度得以维持恒定. 相似文献
92.
银纳米颗粒在钠钙硅酸盐玻璃中的应力分析 总被引:2,自引:0,他引:2
Ag K边X射线吸收精细结构谱分析显示,包裹在钠钙硅酸盐玻璃中的银纳米颗粒的Ag-Ag原子间最近邻距离大于体材料中Ag的间距,说明此时Ag晶格膨胀.晶格膨胀程度依赖于Ag纳米颗粒掺杂玻璃的制备条件.晶格膨胀表明:包裹在钠钙硅酸盐玻璃中的银纳米颗粒处于张应力状态,这主要是由于Ag纳米颗粒与钠钙硅酸盐玻璃基质热失配造成的. 相似文献
93.
Herbert Hambati 《The International journal of environmental studies》2013,70(6):919-939
This study employs participatory disaster risk and vulnerability assessment to analyse vulnerability to disasters in informal settlements in Mwanza city, Tanzania. The results show that a plethora of factors – human, physical, social, economic and natural – interact in complex non-linear ways to shape vulnerability to disaster in informal settlements in Mwanza city. The study shows that coping strategies of some individuals in informal settlements reinforce their risks to disaster. For example, the stones that are positioned on weak roof structures for protection may become projectiles in the event of storm: a kind of disaster by design. This quick-fix coping strategy is unlikely to be sustainable. 相似文献
94.
Daniela Grimm Herbert Schulz Marcus Krüger Jos Luis Corts-Snchez Marcel Egli Armin Kraus Jayashree Sahana Thomas J. Corydon Ruth Hemmersbach Petra M. Wise Manfred Infanger Markus Wehland 《International journal of molecular sciences》2022,23(6)
Cancer is a disease exhibiting uncontrollable cell growth and spreading to other parts of the organism. It is a heavy, worldwide burden for mankind with high morbidity and mortality. Therefore, groundbreaking research and innovations are necessary. Research in space under microgravity (µg) conditions is a novel approach with the potential to fight cancer and develop future cancer therapies. Space travel is accompanied by adverse effects on our health, and there is a need to counteract these health problems. On the cellular level, studies have shown that real (r-) and simulated (s-) µg impact survival, apoptosis, proliferation, migration, and adhesion as well as the cytoskeleton, the extracellular matrix, focal adhesion, and growth factors in cancer cells. Moreover, the µg-environment induces in vitro 3D tumor models (multicellular spheroids and organoids) with a high potential for preclinical drug targeting, cancer drug development, and studying the processes of cancer progression and metastasis on a molecular level. This review focuses on the effects of r- and s-µg on different types of cells deriving from thyroid, breast, lung, skin, and prostate cancer, as well as tumors of the gastrointestinal tract. In addition, we summarize the current knowledge of the impact of µg on cancerous stem cells. The information demonstrates that µg has become an important new technology for increasing current knowledge of cancer biology. 相似文献
95.
加工技术与设备的发展通常会使加工时间缩短.但是新型助剂的应用也可减少加工时间,大大降低成本.随着iFlash系统的应用,漂白温度可降至80℃,活性染料染色后皂洗的时间也大大缩短.因此,织物间歇式染色得到优化,在不增加额外投资的情况下运行更经济. 相似文献
96.
97.
Herbert Matthew S.; Der-Ghazarian Taleen; Palmer Alexandria G.; McDougall Sanders A. 《Canadian Metallurgical Quarterly》2010,18(3):284
Using a one-trial procedure, preweanling rats exhibit robust sensitization regardless of whether drug pretreatment and testing occur in the same or different environments. The purpose of the present study was to determine whether one-trial context-specific and context-independent sensitization of preweanling rats could be dissociated by varying the pretreatment dose of cocaine, by varying the pretreatment drug, or by minimizing interoceptive cues. In Experiments 1a and 1b, rats were pretreated with a broad dose range of cocaine (0–40 mg/kg) before placement in a novel activity chamber or the home cage. In Experiment 2, rats were pretreated with a locomotor-enhancing drug (e.g., methylphenidate, U50,488, or MK-801) before placement in a novel activity or anesthesia chamber. In Experiment 3, rats were anesthetized with isoflurane before cocaine administration to minimize the effects of interoceptive and injection cues. In all experiments, rats were challenged with cocaine on the test day (24 hr later), with locomotion being measured in activity chambers. Results showed that (a) the pretreatment dose of cocaine (10–40 mg/kg) did not differentially affect context-specific and context-independent sensitization; (b) cross-sensitization between methylphenidate and cocaine was observed in the context-specific condition, but not when using a context-independent procedure; and (c) sensitization was evident if injection and interoceptive cues were minimized. One possibility is that associative processes do not modulate the one-trial sensitization of preweanling rats. Alternatively, “unitization” may cause preweanling rats to treat the different environments as equivalent, thus permitting robust sensitization even when drug pretreatment and testing occur in different environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
98.
Trautwein Ulrich; Lüdtke Oliver; Marsh Herbert W.; Nagy Gabriel 《Canadian Metallurgical Quarterly》2009,101(4):853
Results from prior research indicate that a student’s academic self-concept is negatively influenced by the achievement of others in his or her school (a frame of reference effect) and that this negative frame of reference effect is not or only slightly reduced by the quality, standing, or prestige of the track or school attended (a “reflected glory” effect). Going beyond prior studies, the present research used both between-school and within-school approaches to investigate frame of reference and reflected glory effects in education, incorporating students’ own perceptions of the standing of their school and class. Multilevel analyses were performed with data from 3 large-scale assessments with 4,810, 1,502, and 4,247 students, respectively. Findings from all 3 studies showed that, given comparable individual achievement, placement in high-achieving learning groups was associated with comparatively low academic self-concepts. However, students’ academic self-concept was not merely a reflection of their relative position within the class but also substantively associated with their individual and shared perceptions of the class’s standing. Moreover, the negative effects of being placed in high-achieving learning groups were weaker for high-achieving students. Overall, the studies support both educational and social psychology theorizing on social comparison. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
99.
Swift Joshua K.; Callahan Jennifer L.; Heath Christopher J.; Herbert Gregory L.; Levine Jason C. 《Canadian Metallurgical Quarterly》2010,47(2):235
While previous research on deterioration has focused on identifying individuals at risk for negative outcomes, little is known about the nature or pattern by which deterioration occurs. The problem of deterioration is especially salient in training clinics; a setting in which higher deterioration rates have been reported. Two studies were designed to test the applicability of the phase model to deterioration in a training clinic and to replicate the model with a training clinic referral-base sample. In Study 1, the course of therapy was monitored for 135 clients. For the 38 clients who deteriorated during therapy, a model where increased symptoms (demediation) reliably preceded both decreased functioning (dehabilitation) and decreased well-being (demoralization) was found. In Study 2, the same three phases were prospectively monitored for 914 undergraduate students on a weekly basis throughout a single semester. For the 158 individuals who deteriorated during this time, a model where demediation reliably preceded dehabilitation, which preceded demoralization was found. These results have clinical implications for the use of tailored intervention strategies focusing on the deterioration phases. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.