全文获取类型
收费全文 | 9381篇 |
免费 | 179篇 |
国内免费 | 18篇 |
专业分类
9578篇 |
出版年
2012年 | 953篇 |
2011年 | 1126篇 |
2010年 | 242篇 |
2009年 | 108篇 |
2008年 | 877篇 |
2007年 | 881篇 |
2006年 | 776篇 |
2005年 | 661篇 |
2004年 | 573篇 |
2003年 | 602篇 |
2002年 | 495篇 |
2001年 | 323篇 |
2000年 | 492篇 |
1999年 | 194篇 |
1998年 | 38篇 |
1997年 | 45篇 |
1996年 | 44篇 |
1995年 | 29篇 |
1994年 | 16篇 |
1993年 | 45篇 |
1992年 | 24篇 |
1991年 | 25篇 |
1990年 | 22篇 |
1989年 | 27篇 |
1988年 | 24篇 |
1987年 | 25篇 |
1986年 | 14篇 |
1985年 | 20篇 |
1984年 | 30篇 |
1983年 | 31篇 |
1982年 | 18篇 |
1981年 | 21篇 |
1979年 | 16篇 |
1978年 | 19篇 |
1977年 | 14篇 |
1976年 | 19篇 |
1975年 | 15篇 |
1974年 | 16篇 |
1959年 | 29篇 |
1958年 | 89篇 |
1957年 | 66篇 |
1956年 | 62篇 |
1955年 | 58篇 |
1954年 | 49篇 |
1953年 | 54篇 |
1952年 | 34篇 |
1951年 | 41篇 |
1950年 | 37篇 |
1949年 | 24篇 |
1948年 | 17篇 |
排序方式: 共有9578条查询结果,搜索用时 0 毫秒
801.
The present study evaluated the effect of chronic cold stress on intestinal epithelial cell proliferation and inflammation. Male Wistar rats were subjected to cold exposure for three weeks. At the end of the cold exposure, intestinal cell proliferation, luminal nitrite and protein levels, intestinal myeloperoxidase activity and mast cell numbers were evaluated. Severely compromised proliferation rate of the crypt-base cells was observed under chronic stress conditions. Cells isolated from stressed rats showed a decreased DNA content in villus and lower villus cell fractions and an increased DNA content in the crypt cells, as compared to controls. Chronic cold stress resulted in increased luminal nitrite, luminal protein levels, and intestinal myeloperoxidase activity. The number of mast cells was significantly elevated under chronic stress conditions. Chronic cold stress resulted in a compromised intestinal epithelial cell proliferation rate and induced inflammation in the rat small intestine, through the combined action of nitric oxide, neutrophils and mast cells. 相似文献
802.
McGrath RE Pogge DL Stokes JM Cragnolino A Zaccario M Hayman J Piacentini T Wayland-Smith D 《Assessment》2005,12(2):199-209
The extent to which the Comprehensive System for the Rorschach is reliably scored has been a topic of some controversy. Although several studies have concluded it can be scored reliably in research settings, little is known about its reliability in field settings. This study evaluated the reliability of both response-level codes and protocol-level scores among 84 adolescent psychiatric inpatients in a clinical setting. Rorschachs were originally administered and scored for clinical purposes. Among response codes, 87% demonstrated acceptable reliability(> .60), and most coefficients exceeded .80. Results were similar for protocol-level scores, with only one score demonstrating less than adequate reliability. The findings are consistent with previous evidence, indicating reliable scoring is possible even in field settings. 相似文献
803.
804.
Canals J Hernández-Martínez C Fernández-Ballart JD 《Infant behavior & development》2011,34(1):152-160
The aim of this study was to analyze the extent to which the relations and the stability of the neonatal behaviour and the infant behaviour at both 4 and 12 months could be used to predict the infant temperament at 6 years. Seventy-two full-term, normal-weight, healthy children were followed from 3 days postpartum to 6 years. Neonatal behaviour at 3 and 30 days was assessed using the Neonatal Behaviour Assessment Scale (NBAS), behaviour at 4 and 12 months was assessed using the Infant Behaviour Record (IBR) from the Bayley Scales for Infant Development (BSID) and temperament at 6 years was assessed using the Dimensions of Temperament Survey-Revised (DOTS-R). Negative and positive affectivity and attention were the factors extracted from the behaviours of the IBR. Our results showed a low/moderate correlation between neonatal behaviour on the one hand and behaviour at 4 and 12 months and temperament at 6 years on the other hand. The motor performance, orientation and ANS stability of the neonate at 3 and 30 days were predictors of positive and negative affectivity at 4 months. State regulation and ANS stability at 3 days were predictors of negative affectivity and attention respectively at 12 months. Negative affectivity at 12 months and endurance at 30 days were predictors of general activity and persistence/attention at 6 years. Also, an inverse relation was found between state regulation at 30 days and general activity at 6 years, and a positive relation was found between attention at 4 months and persistence/attention at 6 years. We conclude that neonatal behaviour and behaviour in the first year of life are good predictors of temperament at 6 years and that early negative affectivity has an important role on infant temperament development. 相似文献
805.
806.
Brand M Labudda K Kalbe E Hilker R Emmans D Fuchs G Kessler J Markowitsch HJ 《Behavioural neurology》2004,15(3-4):77-85
A high percentage of Parkinson's disease (PD) patients show cognitive impairments in addition to the cardinal motor symptoms. These deficits primarily concern executive functions most probably linked to dysfunctions in prefrontal regions due to decreased dopaminergic transmission in fronto-striatal loops. To investigate possible associations between decision-making and executive functions in PD, we examined 20 non-demented PD patients and 20 healthy control subjects with a neuropsychological test battery and the Game of Dice Task. In this computerised decision-making task, the rules for gains and losses and the winning probabilities are obvious and stable. Thus, strategic components besides feedback processing might influence decision-making in this task. We found that PD patients were impaired in the Game of Dice task performance and that the frequency of disadvantageous choices correlated with both executive functions and feedback processing. We suggest that decision-making deficits of PD patients in explicit gambling situations might be associated with dysfunctions in two different fronto-striatal loops: the limbic-orbitofrontal-striatal loop, involved in feedback processing, and the dorsolateral prefrontal-striatal loop, involved in executive functions. 相似文献
807.
808.
Schmitt DP Alcalay L Allik J Angleitner A Ault L Austers I Bennett KL Bianchi G Boholst F Borg Cunen MA Braeckman J Brainerd EG Caral LG Caron G Casullo MM Cunningham M Daibo I De Backer C De Souza E Diaz-Loving R Diniz G Durkin K Echegaray M Eremsoy E Euler HA Falzon R Fisher ML Foley D Fry DP Fry S Ghayur MA Golden DL Grammer K Grimaldi L Halberstadt J Haque S Herrera D Hertel J Hoffmann H Hooper D Hradilekova Z Hudek-Kene-evi J Jaafar J Jankauskaite M Kabangu-Stahel H Kardum I Khoury B 《Journal of personality and social psychology》2004,86(4):560-584
809.
Two self-paced reading experiments investigated syntactic ambiguity resolution in Spanish. The experiments examined the way in which Spanish subjects initially interpret sentences that are temporarily ambiguous between a sentence complement and a relative clause interpretation. Experiment 1 examined whether the sentence complement preference found in English is observed in Spanish speaking subjects. In Experiment 2, verbal mood was manipulated in order to study the influence of verb-specific information on sentence processing. Since subcategorization for a subjunctive complement clause is generally assumed to be a lexical property of some verbs, the manipulation of the mood of the embedded verb affords us an interesting and novel way to examine the influence of lexical information on syntactic ambiguity resolution. Experiment 1 showed that Spanish speakers initially interpret the ambiguous that-clause as a sentence complement. Experiment 2 showed that verb-specific information, in particular, the information that specificies that a verb subcategorizes for a subjunctive complement, is accessed and used rapidly and affects the ambiguity resolution process. The results are discussed in relation to current models of sentence processing. 相似文献
810.