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The focus of the present study was on the intersegmental relationships that emerge when both task and oganismic constraints are imposed upon the coordination system. Seven right-handed subjects were required to reach and grasp a cup (hand transport phase) and place it on a designated target (cup transport phase), using either their preferred or nonpreferred hand. The kinematics of the movement were examined as a function of task (grasping a full cup versus grasping an empty one) and organismic (preferred or nonpreferred hand) constraints. During the hand transport phase, a task constraint effect was revealed through an increase in the low-velocity phase for the full cup condition. This constraint coexisted with a decrease in angular motion of the shoulder and elbow joints, indicating subjects reduced the number of variables to be independently controlled in the final homing-in stage of the movement. Accompanying this decrease in angular change was an increase in the displacement of the trunk. During the cup transport phase, the trunk was shown to contribute significantly more to the movement in the full cup condition and for the left hand movements, thereby increasing the stability of the movement system. These findings are in agreement with Bernstein's (1967) notion of fixating parts of the body as an initial solution to a movement problem, and they lend support to the concept of a proximodistal organization of coordination.  相似文献   
203.
It has been established through several decades of research that children's home environments significantly influence their development. Many researchers have also been interested in expanding research beyond indirect measures of the home environment, such as socioeconomic status, to help understand the nature of specific environmental mechanisms which influence early behavior and cognitive development. The Home Observation for Measurement of the Environment (HOME) Inventory was developed to meet these needs. Specifically, HOME measures the quality of stimulation in a child's early family environment. Almost all studies of the approach's reliability and validity have been conducted with US samples. HOME is, however, being used in other countries. The authors report their findings from a study of whether the psychometric properties of HOME based upon US samples parallel those found in Costa Rica, and whether HOME discriminates between Costa Rican environments with different associations to child health and development. Focus centers upon the infant/toddler version of the HOME Inventory. HOME data for 183 healthy Costa Rican infants were compared to the original HOME standardization sample from Little Rock, Arkansas. The study found the HOME Inventory to be helpful in identifying children at risk for delayed development in this Latin American sample. Lower HOME scores related to a shorter duration of breastfeeding and differentiated children with iron deficiency anemia in infancy, a condition associated with long-lasting developmental disadvantage.  相似文献   
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2001年的科学哲学   总被引:1,自引:0,他引:1  
一种民主制度的最重要也是讨论最少的任务之一就是要保护它的成员免遭这种制度中的意识形态的伤害.必须正确地看待所有的意识形态.人们必须把它们当作神话故事来看待,它们能告诉人很多有趣的事,但也包含了很多谬误和令人生厌的谎言.当人们按照某一观点行动时,他们的态度也应该像密探一样,为了在一个陌生的国家里获得成功而采纳它的信仰并在细枝末节上按照这些信仰去做,但并不全盘接受.这一点适用于所有的信仰,适用于基督教上帝的存在这一信仰,适用于所有的人生来平等的信仰,也适用于科学.那么,这是否是一种陌生和荒谬的态度呢?科学当然总是处在与权威主义和迷信战斗的前沿.相对于宗教信仰而言,我们有了越来越大的思想自由,这应当归功于科学;人类从古代的僵硬思维方式中解放出来,也应当归功于科学.今天,这些思维方式仅仅是一些糟糕的  相似文献   
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Male Siamese fighting fish, Betta splendens, swam through a ring in an aquarium, breaking a photocell beam and initiating an unsignaled, resetting delay interval. Following delays of 0 s, 10 s, or 25 s, a 15-s mirror presentation released an aggressive display by the fish. Swimming through the ring increased in the absence of either a period of acclimatization to the reinforcer (analogous to magazine training when appetitive reinforcers are used) or explicit training of the response by the experimenters. Response rates were a decreasing function of delay duration. Other fish exposed to a schedule of response-independent mirror presentations failed to acquire and maintain the response. The results demonstrate the robustness and generality of the phenomenon of response acquisition with delayed reinforcement. They further qualify earlier observations about behavioral mechanisms involved in the phenomenon.  相似文献   
208.
The importance of consulting with other professionals to maintain acceptable standards of care is well documented in many health care professions. However, evidence indicates that many psychologists fail to utilize consultation when needed, and that consultation use varies along dimensions such as the education and training of the consultee, the type of setting, number of years in practice, and proximity to available consultants. In this article, we review the research on the use of consultation by psychologists as well as other health care professionals. We discuss the clinical, ethical, and legal implications of seeking consultation as a professional psychologist. Finally, a detailed and practical model for the regular use of consultation is given to improve the routine use of consultation in clinical practice.  相似文献   
209.
现实论(actualism)这项方案,旨在清除逻辑与模态形而上学中那些讨人嫌的本体论承诺。它从一切存在的都是现实的这个观点出发,试图重新解释语言,以避免承诺“可能体”(possibilia)的存在。所谓“可能体”,指那些可能的,但非现实的对象。量化模态逻辑(QML)似乎就要求这种对象存在。最简QML为古典量化理论与模态命题逻辑之合并,可是它使巴康(Barcan)公式(今日x由→ax令Q)有效。从而,由可能存在一头会说话的驴子这个事实,就推出了存在某物,它可能是一头会说话的驴子。这看起来在宣称一个可能实体的存在(假定每个现实的东西都不可能是会说话的驴子)。现实论者们大力主张克里普克(Kripke)所描述的语义学,以此来免除这项承诺,这种语义学采用了可变论域,因而使巴康公式归于无效。  相似文献   
210.
推断论伦理学家就堕胎和安乐死的问题而提出的命题,主要是澳大利亚人P.辛格的那些命题,一直引起激烈的论战。推断论将生命保护理解为一种利益保护,它使个体的生命权利依赖于成为人的那种特性。按照推断论的观点,不是所有人类的个体都是人,因而就不能赋予非—个人的人类个体以生命权利——这在实践中是有相应的结果的。不管对P.辛格的命题在感情上的反应多么可以理解,光靠这些命题是得不到什么结果的,因为重要的是研究这些命题所引用的证据,研究那些已经决定了推断论的问题表述的前概念。只要推断论的潜在的前题不受到怀疑,人们也许将无法摆脱单纯的口头侮辱。  相似文献   
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