全文获取类型
收费全文 | 783篇 |
免费 | 53篇 |
国内免费 | 36篇 |
专业分类
电工技术 | 8篇 |
综合类 | 27篇 |
化学工业 | 301篇 |
金属工艺 | 26篇 |
机械仪表 | 83篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
轻工业 | 164篇 |
武器工业 | 2篇 |
无线电 | 55篇 |
一般工业技术 | 32篇 |
冶金工业 | 47篇 |
原子能技术 | 12篇 |
自动化技术 | 109篇 |
出版年
2024年 | 2篇 |
2023年 | 10篇 |
2022年 | 110篇 |
2021年 | 128篇 |
2020年 | 16篇 |
2019年 | 19篇 |
2018年 | 15篇 |
2017年 | 24篇 |
2016年 | 25篇 |
2015年 | 29篇 |
2014年 | 35篇 |
2013年 | 45篇 |
2012年 | 59篇 |
2011年 | 45篇 |
2010年 | 22篇 |
2009年 | 33篇 |
2008年 | 44篇 |
2007年 | 37篇 |
2006年 | 21篇 |
2005年 | 29篇 |
2004年 | 20篇 |
2003年 | 23篇 |
2002年 | 16篇 |
2001年 | 13篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1981年 | 2篇 |
1964年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有872条查询结果,搜索用时 31 毫秒
51.
Lee C. Drickamer 《Journal of chemical ecology》1989,15(5):1407-1421
House mice release chemosignals in their urine that influence the timing of puberty and reproductive condition in conspecific females. These experiments tested the possibility that mice depositing urine containing chemosignals that affect puberty and reproduction do so differentially with respect to urine cues from conspecifics. Mice were tested in cages containing samples of urine or water on cotton in wire mesh capsules protruding from the cage floor. Their urine deposition patterns were recorded on squares of filter paper positioned below the cages. Males deposited more urine than females housed in groups, estrous females, diestrous females, or prepubertal females. All groups of mice deposited urine in a nonrandom fashion with regard to urine cues from conspecifics. Male mice deposited more urine near locations previously soiled by females than near water or other males. Grouped females deposited more urine near male urine cues and avoided depositing urine near urine from other group-housed females. Both estrous and diestrous female mice deposited more urine near males than near other urine cues or water, possibly to attract mates. Prepubertal females avoided depositing their urine near male urine and urinated more near urine from grouped females than near other urine types or water. Young females may be avoiding possible male mates until they have attained puberty. This avoidance behavior may enhance the long-term reproductive success of the females that otherwise might mature and mate at too young an age. 相似文献
52.
53.
通过介绍基于视觉的空间定位方法,解释了真三维立体鼠标的实现原理,搭建了真三维立体鼠标系统。针对真三维立体鼠标的空间静态与动态抖动问题,研究了真三维立体鼠标的去抖方法。为了实现两点触控,提出了鬼点去除方法,实现了两个指尖的位置识别。实验证明,在不需要佩戴任何标记和传感器的条件下,基于视觉的立体鼠标能够在真三维显示器上准确绘制图形且不受室内环境光干扰。 相似文献
54.
目的:观察鼠神经生长因子联合椎旁神经根阻滞治疗肺癌併发带状疱疹神经痛的临床疗效。方法:将40例具有典型带状疱疹神经痛表现的肺癌患者随机分为A组(实验组)和B组(对照组)各20例。治疗组给予鼠神经生长因子肌注1支每日一次+椎旁神经根阻滞每周2次;对照组给予椎旁神经阻滞每周2次。观察治疗后1周、2周疼痛指标及1月后的随访结果。结果:比较两组患者的疼痛指标及总体疗效,A组优于B组,有显著性意义P0.05。结论:鼠神经生长因子联合椎旁神经根治疗肺癌伴带状疱疹神经痛优于单纯椎旁神经阻滞治疗。 相似文献
55.
56.
一种3D无线鼠标设计的新思路,以凌阳单片机为核心控制器,通过MEMS加速度传感器和触控模块,感知鼠标的移动动作,同时,通过无线射频完成无线通信,从而实现鼠标功能。使用过程中,鼠标不仅可以放于载体使用,而且可以在空中使用,增添了鼠标的操控方式,同时,大大增加了此无线鼠标的适用范围。 相似文献
57.
垂直鼠标设计中的人机工程学应用分析 总被引:1,自引:0,他引:1
以多彩科技生产的垂直鼠标为研究对象,通过与传统平放鼠标的人机设计对比分析,论述了由于鼠标革命的产物——垂直鼠标的熨斗形外观设计及右侧面的按键巧妙布置,进而消除了传统平放鼠标人机设计缺陷造成使用者手臂长期不适的状况,总结了垂直鼠标在人机设计中的独特之处,为设计师在产品设计中换位思考提供了新的思路和方法。 相似文献
58.
Pietropaolo Susanna; Feldon Joram; Yee Benjamin K. 《Canadian Metallurgical Quarterly》2008,122(4):733
The triple-transgenic mouse line (3×Tg-AD) harboring PS1M146V, APPSwe, and taup301L transgenes represents the only transgenic model for Alzheimer's disease (AD) to date capturing both β-amyloid and tau neuropathology. The present study provides an extensive behavioral characterization of the 3×Tg-AD mouse line, evaluating the emergence of noncognitive and cognitive AD-like symptoms at two ages corresponding to the early (6-7 months) and advanced (12-13 months) stages of AD-pathology. Enhanced responsiveness to aversive stimulation was detected in mutant mice at both ages: the 3×Tg-AD genotype enhanced acoustic startle response and facilitated performance in the cued-version of the water maze. These noncognitive phenotypes were accompanied by hyperactivity and reduced locomotor habituation in the open field at the older age. Signs of cognitive aberrations were also detected at both ages, but they were limited to associative learning. The present study suggests that this popular transgenic mouse model of AD has clear phenotypes beyond the cognitive domain, and their potential relationship to the cognitive phenotypes should be further explored. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
59.
60.
Dah-Lu Chu Hong-Jey Chiou Da-Peng Wang 《Drug development and industrial pharmacy》1994,20(18):2775-2785
In vitro iontophoretic delivery of nefopam hydrochloride was conducted to study the effects initial drug concentration, pH, ionic strength and viscosity of the donor solutions on the transdermal flux through a hairless mouse skin. Stability of nefopam hydrochloride under the experimental conditions was investigated. Type of electrode, current intensity, electric voltage and electrode distance were evaluated. Appropriate conditions were selected to minimize the potential degradation problems of nefopam hydrochloride during iontophoresis. Results show that the silver/silver chloride electrode provides better drug stability than the platinum electrode. Higher current intensity resulted in faster transdermal flux and therefore better drug permeability. The increase in the drug permeability appears to be proportionally increased as the current intensity increases in the range of 0.253 to 1.265 mA/cm2. The iontophoretic transdermal delivery of nefopam hydrochloride was observed to increase as the drug concentration in the donor site was increased until it's close to the equilibrium concentration. The optimum pH to achieve the best iontophoresis under constant current was determined to be at pH 3.0. This may be due to the highest available charge density of nefopam was achieved at this pH to provide the best conductance. A decrease in the iontophoretic transdermal flux was encountered as an increase in the solution ionic strength due to the increased competition of similar charged ions with the available current. The increase in the donor solution viscosity decreased the conductivity of the ions and hindered the trandermal flux of the drug under iontophoresis. 相似文献