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   72994篇
  免费   1358篇
  国内免费   7篇
  74359篇
  2020年   764篇
  2019年   914篇
  2018年   1226篇
  2017年   1299篇
  2016年   1390篇
  2015年   995篇
  2014年   1204篇
  2013年   5303篇
  2012年   2198篇
  2011年   2196篇
  2010年   1426篇
  2009年   1327篇
  2008年   1970篇
  2007年   1963篇
  2006年   1743篇
  2005年   1619篇
  2004年   1487篇
  2003年   1388篇
  2002年   1432篇
  2001年   2189篇
  2000年   2084篇
  1999年   1600篇
  1998年   731篇
  1997年   669篇
  1996年   650篇
  1992年   1442篇
  1991年   1313篇
  1990年   1354篇
  1989年   1193篇
  1988年   1228篇
  1987年   1156篇
  1986年   1206篇
  1985年   1227篇
  1984年   1010篇
  1983年   959篇
  1982年   687篇
  1979年   1150篇
  1978年   769篇
  1977年   723篇
  1976年   689篇
  1975年   949篇
  1974年   1086篇
  1973年   1151篇
  1972年   928篇
  1971年   887篇
  1970年   846篇
  1969年   883篇
  1968年   1119篇
  1967年   1006篇
  1966年   871篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Short-term memory for Chinese characters and radicals   总被引:1,自引:0,他引:1  
Short-term memory for Chinese radicals and characters, varying in orthographic complexity, frequency, and—for radicals—intercharacter frequency (the number of compound characters that contain the radical), was studied using an immediate free-recall task. When radicals or characters are relatively frequent, so that their pronunciations are well known by literate Chinese, they seem to be maintained in verbal form in short-term memory. For these stimuli, intercharacter frequency and complexity have relatively small influences on memory span. Stimuli low in frequency, with pronunciations that are not apt to be known, seem to be maintained in visual form in short-term memory. Memory span is much smaller for these stimuli and is influenced by both intercharacter frequency and complexity. Furthermore, short-term memory for relatively high-frequency characters is interfered with more by a verbal than by a visual intervening task, whereas the opposite is true for low-frequency characters.  相似文献   
43.
The modulation of attacks, genital sniffs, and mounts in male SJL/J mice by ovarian-dependent urogenital substances in the urine voided by estrous females was examined. Urogenital substances were applied onto the external urogenital areas of ovariectomized mice. When compared with urine voided by estrous females, which stimulated genital sniffing, mounting, and reduced aggression, bladder urine was ineffective. Genital sniffing and mounting was stimulated by estradiol-17 beta, vaginal fluids, and preputial extract. Aggression was reduced by estradiol-17 beta, urethral catheterized urine, and vaginal fluids. Preputialectomy reduced, but did not eliminate, urinary stimulation of genital sniffing and mounting. Preputial extract stimulated aggression. Urogenital substances from ovariectomized females were ineffective in reducing attacks and stimulating genital sniffs and mounts. It was concluded that the ovarian-dependent chemosignals in the urine voided by estrous females are contributed by the urethra, vagina, and preputial gland, perhaps in part through the excretion of unconjugated estrogens.  相似文献   
44.
Serotonergic and opiate interactions in the modulation of drug- and environmental-induced analgesia were assessed in 6-day-old Sprague-Dawley-derived rat pups using tail-flick testing procedures. In these experiments the serotonergic antagonist metergoline was observed to attenuate both the analgesia induced by the opiate agonist morphine and the analgesia induced by isolation from siblings and the dam, an environmental manipulation which has previously been shown to be associated with increases in opiate activity. In contrast, the opiate antagonist naloxone was observed to be ineffective in blocking not only analgesia induced by the serotonergic agonist quipazine, but also analgesia induced by long-term deprivation from the dam and food, a manipulation that has been previously reported to induce increases in serotonergic utilization. These results suggest that in the neonate, as in the adult, the serotonergic modulation of nociception appears to occur "downstream" from the opiate systems serving to regulate nociception following both drug- and environmental-induced alterations in pain sensitivity. Analgesia induced by long-term deprivation from food and the dam appears to be strongly related to increases in serotonergic activity and relatively unaffected by opiate antagonism, whereas analgesia induced by isolation from siblings and the dam may be related to increases in opiate activity, but modulated by serotonergic systems serving to regulate pain responsivity. Thus alterations in the environment, mediated at least in part by alterations in opiate and serotonergic activity, appear to play an important role in influencing the sensitivity of the neonate to pain stimuli.  相似文献   
45.
46.
47.
Despite widespread popular belief in the activation of recurrent lesions in genital herpes simplex virus (HSV) by psychosocial stress, little empirical evidence supports that contention. This study retrospectively examined the role of stress in activation of HSV lesions as mediated by social support. Participants were 59 volunteers who had self-reported culture-positive genital HSV for at least 10 months. Measures of stress proneness (State-Trait Anxiety Inventory; STAI-Trait), recent stressful events (Schedule of Recent Events; SRE), and subjective appraisal of stress (global self-rating) were administered along with measures of general social support and herpes-specific social support. When retrospective reports of HSV symptoms were examined using a multiple-regression approach, duration of disease and amount of herpes-specific social support were found to be significant moderators of the relation between stress and number of HSV recurrences in the preceding 12 months. When duration of disease was short (less than 4 years), stress (SRE) and number of recurrences were positively associated; when disease duration was longer, there was no relationship. Similarly, at low levels of herpes-specific social support, a positive relation between stress (SRE) and number of recurrences was found. However, at higher levels of herpes-specific social support, no association was found. No relation was found between stress proneness (STAI-Trait) and HSV symptoms. However, subjective appraisal (global rating) of stress in the preceding 12 months was positively and significantly correlated with reported number of recurrences. Results are discussed in terms of their clinical implications.  相似文献   
48.
Analogical transfer, problem similarity, and expertise   总被引:6,自引:0,他引:6  
When we encounter a new problem, we are often reminded of similar problems solved earlier and may use the solution procedure from an old problem to solve a new one. Such analogical transfer, however, has been difficult to demonstrate empirically, even within a single experimental session. This article proposes a framework for conceptualizing analogical problem solving that can account for the conflicting findings in the literature. In addition, the framework leads to two predictions concerning the transfer behavior of experts and novices. These predictions concern both positive and negative transfer and are based on the different types of features included in the problem representations of experts and novices. First, when two problems share structural features but not surface features, spontaneous positive transfer should be more likely in experts than in novices. Second, when two problems share surface but not structural features, spontaneous negative transfer should be stronger for novices than for experts. These predictions were supported by the results of three experiments involving college students solving a complex arithmetic word problem.  相似文献   
49.
Group work as an integral part of counsellor training appears to have been under-utilised. Certainly it is the case that empirical evaluations of such group work appear rarely in guidance and counselling journals. An attempt is made to remedy these deficiencies by reviewing studies relevant to counsellor training and to report on 17 years of research and experience with group work within a counsellor training programme at a New Zealand university.  相似文献   
50.
The vocationally-indecisive individual presents a major counselling problem. The theory and research behind career indecision is discussed and a counselling approach based on identity formation is outlined. Four identity statuses — Identity Achievements, Foreclosures, Identity Diffusions, and Moratoriums — are described and counselling approaches for each are explored.  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