首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1092篇
  免费   126篇
  国内免费   261篇
  1479篇
  2024年   4篇
  2023年   21篇
  2022年   33篇
  2021年   43篇
  2020年   53篇
  2019年   52篇
  2018年   73篇
  2017年   54篇
  2016年   54篇
  2015年   39篇
  2014年   36篇
  2013年   110篇
  2012年   80篇
  2011年   91篇
  2010年   69篇
  2009年   75篇
  2008年   77篇
  2007年   94篇
  2006年   79篇
  2005年   71篇
  2004年   43篇
  2003年   32篇
  2002年   16篇
  2001年   17篇
  2000年   18篇
  1999年   19篇
  1998年   8篇
  1997年   7篇
  1996年   7篇
  1995年   8篇
  1994年   9篇
  1993年   6篇
  1992年   9篇
  1991年   6篇
  1989年   9篇
  1988年   2篇
  1987年   6篇
  1986年   3篇
  1985年   7篇
  1984年   7篇
  1983年   3篇
  1982年   6篇
  1981年   8篇
  1980年   4篇
  1979年   4篇
  1978年   1篇
  1975年   3篇
  1972年   1篇
  1964年   1篇
  1959年   1篇
排序方式: 共有1479条查询结果,搜索用时 0 毫秒
121.
In a recent episode of the TV series Star Trek: The Next Generation, Captain Jean-Luc Picard and the crew of the starship Enterprise land surreptitiously on a distant planet. When they are discovered by the humanoid inhabitants, who have webbed feet and toes and a raised ridge on their foreheads, the human invaders explain that their mission is to assist planetary cultures like theirs when they are ready to begin space travel.  相似文献   
122.
A phase transition of MgS under high pressure is investigated using a first-principles method. It is found from energy-volume calculations that the rock-salt (B1) phase of MgS transforms into a FeSi-type (B28) phase at 143?GPa. The calculated ground-state parameters in the B1 phase are in excellent agreement with available experimental and theoretical data. Ab initio phonon calculations are also performed to investigate the structural behaviour of MgS under high pressure. An unstable transverse acoustic mode and a phase transition from B1 to B28 phase at ~143.7?GPa driven by this soft mode are predicted. The B28 structure of MgS is stable up to 350?GPa according to lattice dynamics calculations.  相似文献   
123.

High-resolution grazing-incidence parallel-beam powder diffraction has been used to detect the subsurface damage below alumina surfaces subjected to polishing with cerium oxide or diamond. Despite very significant evolution of the surface morphology, no changes in the subsurface strains were observed over a 20min period of polishing with ceria. For both polishing materials, the variation with angle in the full-width at half-height maximum was successfully modelled by a strain distribution that fell exponentially with increasing depth. Although the surface amplitude and depth dependence parameter are coupled, we have been able to place upper limits on the depth to which the damage extends. Under realistic assumptions, the depth of damage induced by 1µm diamond paste is comparable with that from 3µm ceria polish.  相似文献   
124.

The average velocities of screw dislocations in Ni 3 Al single crystals have been directly measured as a function of resolved shear stress (RSS) and orientation in the temperature domain of the flow stress anomaly using the etch-pit technique. The velocity was found to be extremely sensitive to the RSS in all cases. In contrast with ordinary metals, the screw dislocation velocities in Ni 3 Al show anomalous behaviour; under a constant RSS, the velocities decrease dramatically with increasing temperature. Furthermore, the velocities and the tension-compression asymmetry of the velocities depend on the orientation of applied stress.  相似文献   
125.
This study investigated the influences of sentence surface forms on the misinformation effect. After viewing a film clip, participants received a post‐event narrative describing the events in the film. Critical sentences in the post‐event narrative, presented in either a statement or a question form, contained misinformation instead of questions with embedded false presuppositions; thus participants did not have to answer questions about the original event. During the final cued‐recall test, participants were informed that any relevant information presented in the post‐event narrative was not in the original event and that they should not report it. Consistent with previous findings, Experiment 1 demonstrated that post‐event information presented as an affirmative statement produced the misinformation effect. More importantly, post‐event information presented in a question form, regardless of whether it contained a misleading or studied item, increased the recall of correct information and reduced false recall. Experiment 2 replicated the main finding and ruled out an alternative explanation based on the salience of misleading items. Post‐event information presented in a question form created a condition similar to that which produces the testing effect.  相似文献   
126.
This study examined prevalence and predictors of posttraumatic growth in 180 accidentally injured patients of mainland China in their convalescence stage, investigating its relationships with demographic and accidental injury variables, personality, posttraumatic stress disorder (PTSD) symptoms, and coping styles. Our results showed that posttraumatic growth (PTG) presented mostly in the domain of Relating to Others and indicated that PTG was significantly related to marital status, educational level, personality, coping styles, and PTSD symptoms. Avoidance of PTSD symptoms, Openness to experience, and positive coping were significant predictors of PTG. The findings emphasize that when promoting PTG of accidentally injured patients, healthcare providers should facilitate patients utilizing personal resources, understand PTG coexists with PTSD symptoms, and adjust interventions based on the coping styles the patients have adopted.  相似文献   
127.
Previous studies have shown that a plausible preview word can facilitate the processing of a target word as compared to an implausible preview word (a plausibility preview benefit effect) when reading Chinese (Yang, Wang, Tong, & Rayner, 2012; Yang, 2013). Regarding the nature of this effect, it is possible that readers processed the meaning of the plausible preview word and did not actually encode the target word (given that the parafoveal preview word lies close to the fovea). The current experiment examined this possibility with three conditions wherein readers received a preview of a target word that was either (1) identical to the target word (identical preview), (2) a plausible continuation of the pre-target text, but the post-target text in the sentence was incompatible with it (initially plausible preview), or (3) not a plausible continuation of the pre-target text, nor compatible with the post-target text (implausible preview). Gaze durations on target words were longer in the initially plausible condition than the identical condition. Overall, the results showed a typical preview benefit, but also implied that readers did not encode the initially plausible preview. Also, a plausibility preview benefit was replicated: gaze durations were longer with implausible previews than the initially plausible ones. Furthermore, late eye movement measures did not reveal differences between the initially plausible and the implausible preview conditions, which argues against the possibility of misreading the plausible preview word as the target word. In sum, these results suggest that a plausible preview word provides benefit in processing the target word as compared to an implausible preview word, and this benefit is only present in early but not late eye movement measures.  相似文献   
128.
Reunion behavior following stressful separations from caregivers is often considered the single most sensitive clue to infant attachment patterns. Extending these ideas to middle childhood/early adolescence, we examined participants' neural responses to reunion with peers who had previously excluded them. We recorded event‐related potentials among nineteen 11‐ to 15‐year‐old youth previously classified on attachment interviews (11 secure and 8 insecure‐dismissing) while they played a virtual ball‐toss game (Cyberball) with peers that involved fair play, exclusion and reunion phases. Compared to secure participants, dismissing participants displayed a greater increment in the N2 during reunion relative to fair play, a neural marker commonly linked to expectancy violation. These data suggest a greater tendency toward continued expectations of rejection among dismissing children, even after cessation of social exclusion. In turn, the link between self‐reported ostracism distress and neural signs of negative expectancy at reunion was moderated by attachment, such that self‐reports were discordant with the neural index of expectancy violation for dismissing, but not for secure children. A video abstract of this article can be viewed at http://www.youtube.com/watch?v=qzoRel5c-4s .  相似文献   
129.
本工作对两例先天性无痛症患者对于致痛性强刺激的知觉和反应进行了研究(例1女,10岁,例2男,13岁)。对照组为20例正常儿童,性别和年龄均与患儿相匹配。 结果:1),生活中痛:两例患儿均无(包括痛感觉和痛反应)。2)实验性痛:①痛感觉:两例患儿均无;②“痛”反应:例1有“痛”反应(脉搏和呼吸的变化以及行为反应明显,大致与正常儿童相似)。例2无“痛”反应(脉搏和呼吸的变化轻微,无行为反应,与正常儿童不同)。 由结果看来,先天性无痛症患者似乎可分为两种类型:不完全型(如同例1)和完全型(如同例2)。存在有“痛”反应而无痛感觉的无痛症患者。 本工作结果从另一侧面为痛的两成分学说提供了依据。  相似文献   
130.
汉语词类歧义解决初探   总被引:1,自引:0,他引:1  
武宁宁  舒华 《心理科学》2003,26(1):60-63
采用自定步速移动窗口阅读实验范式,考察汉语词类歧义解决过程。阅渎材料为含有单字词类歧义词的句子,歧义词前面的语境不提供明确的偏向性信息.后语境提供解歧信息。结果发现,主要用法和次要用法的句子都在解歧区比控制句阅读时间加长,表明汉语词类歧义解决没有即时受到歧义词两种用法的相对频率影响,而是在歧义词处暂时不进行完全的句法分配,延迟到获得充分解歧信息的时候才分配句法角色。这一结果支持词类歧义解决的延迟模型。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号