全文获取类型
收费全文 | 534篇 |
免费 | 43篇 |
国内免费 | 23篇 |
专业分类
600篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 13篇 |
2021年 | 23篇 |
2020年 | 16篇 |
2019年 | 36篇 |
2018年 | 18篇 |
2017年 | 27篇 |
2016年 | 28篇 |
2015年 | 27篇 |
2014年 | 34篇 |
2013年 | 26篇 |
2012年 | 13篇 |
2011年 | 29篇 |
2010年 | 27篇 |
2009年 | 23篇 |
2008年 | 29篇 |
2007年 | 26篇 |
2006年 | 26篇 |
2005年 | 14篇 |
2004年 | 21篇 |
2003年 | 14篇 |
2002年 | 9篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 6篇 |
1998年 | 11篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有600条查询结果,搜索用时 15 毫秒
1.
Meta‐analyses evaluating the association between the serotonin transporter polymorphism (5‐HTTLPR) with neuroticism and depression diagnosis as phenotypes have been inconclusive. We examined a gene–environment interaction on a cognitive vulnerability marker of depression, cognitive reactivity (CR) to sad mood. A total of 250 university students of European ancestry were genotyped for the 5‐HTTLPR, including SNP rs25531, a polymorphism of the long allele. Association analysis was performed for neuroticism, CR and depression diagnosis (using a self‐report measure). As an environmental pathogen, self‐reported history of childhood emotional abuse was measured because of its strong relationship with depression. Participants with the homozygous low expressing genotype had high CR if they had experienced childhood emotional maltreatment but low CR if they did not have such experience. This interaction was strongest on the Rumination subscale of the CR measure. The interaction was not significant with neuroticism or depression diagnosis as outcome measures. Our results show that 5‐HTTLPR is related to cognitive vulnerability to depression. Our findings provide evidence for a differential susceptibility genotype rather than a vulnerability genotype, possibly because of the relatively low levels of abuse in our sample. The selection of phenotype and environmental contributor is pivotal in investigating gene–environment interactions in psychiatric disorders. 相似文献
2.
3.
Males of the planthopper Ribautodelphax imitanswere exposed to playbacks of either conspecific or heterospecific (R. imitantoides)female calls during their development from egg to adult, and thereafter these, as well as naive males,were offered a two- way choice between these calls. Males of all treatments approached the conspecific call significantly more often. However, males primed by the conspecific call chose the heterospecific call almost four times less often than did males primed by heterospecific calls or naive males, thus showing that the preference for conspecific calls can be partly learned. Males primed by heterospecific calls performed very similarly to completely naive males, suggesting that the signal recognition mechanism is much less sensitive to heterospecific calls than to conspecific calls. Males with experience of the conspecific female call tended to take more time to reach the call source in the trials than both other types of males. The evolutionary implications of these findings are discussed. 相似文献
4.
The effect of adult learning through an oviposition experience, and pre-adult learning through development inside a host was
investigated in two strains of an Australian egg parasitoid,Trichogramma nrivelae (Hymenoptera: Trichogrammatidae). Host response was measured in two types of laboratory preference tests. In single host
tests, females reared on three lepidopteran hosts (Heliothis punctigera (Noctuidae),Papilio aegeus (Papilionidae), andHypolimnas bolina (Nymphalinae)) were presented host eggs individually, and allowed two ovipositions. Pre-adult experience affected host preference
in only one strain, while acceptance of a host was increased in both strains when they had previously oviposited in this host
species. An oviposition experience had a stronger effect on host preference than pre-adult experience. In choice tests, pairwise
combinations of hosts were arranged in an alternating grid. The ratio of host acceptances to host contacts was computed for
the whole test and up to the first oviposition. These indicated that effects of rearing host were weak or absent, but the
host chosen initially had a strong effect on host preference. Relative size of the hosts had a strong effect on choice of
the first host. The implications of learning inTrichogramma are discussed in relation to host preference testing procedures and the selection of candidate strains for mass rearing and
inundative release. 相似文献
5.
C. M. Berman 《International journal of primatology》1980,1(2):153-170
Several aspects of agonistic experience are described for freeranging infant rhesus monkeys (Macaca mulatta)on Cayo Santiago. Even before infants are fully integrated with peers in rank dominance based on maternal ranks,infants of highranking mothers tend to be threatened less frequently by other members of the group and are less likely to
be threatened by unfamiliar individuals than are infants of lowranking mothers. There is no evidence that fearful interactions
between pairs of infants are related to their mother’s ranks before 22 weeks of age. However, an imperfect hierarchy can be
constructed for infants between 27 and 30 weeks of age. At this age,infants of higherranking mothers are also more likely to receive protection when threatened than are infants of lowerranking
mothers. When protected, their protectors are less likely to emit fearful gestures to the infants’ threatener. Close female
relatives appear to play a large role in the protection of infants and may be more directly responsible for the differences
described above than the mother, other relatives, or other highranking members of the group. It is suggested that more than
one mechanism, including intervention by the mother and by close female relatives,may be important in rank acquisition among peers. 相似文献
6.
In nonhuman animals, the phenomenon of rapid facial mimicry (RFM)—the automatic, involuntary, and rapid (<1 s) replication of others’ facial expressions—has been mainly investigated in the playful domain. In immature lowland gorillas Gorilla gorilla gorilla both play face (PF) and full PF (FPF) are rapidly mimicked between the players. This makes the species suitable to test hypotheses on the factors influencing RFM during play. The observations on 3 captive groups of lowland gorillas (N = 27) revealed that contrary to expectations, the closeness of social bond negatively influenced the occurrence of RFM but it did not affect either RFM latency or its overlapping index (OVERLAP). RFM was affected by the degree of symmetry of play fighting: the more balanced the session, the higher the occurrence of RFM. Players of the same sex class responded faster than players of different sex. These findings suggest that RFM may help synchronizing behaviors of playmates matching in size (same-sex) and promote symmetric playful interactions. “Laughing together” (measured by the RFM OVERLAP) lasted longer when the responder perfectly mirrored the partner expression (PF→PF; FPF→FPF). If PF and FPF convey information on the different play roughness degree, through “laughing together” the players could coordinate their actions and share positive moods and playful intensity. If the perfect congruency in the motor resonance, also known as social sensitivity, can foster a possible emotional dialogue between gorillas remains to be investigated. 相似文献
7.
8.
Experience acquisition by Trichogramma australicum Girault (Hymenoptera: Trichogrammatidae) 总被引:1,自引:0,他引:1
We investigated experience acquisition (alpha-conditioning) by females of the parasitoid Trichogramma australicum using host eggs of the noctuid moth Helicoverpa armigera (Hübner). We compared the acceptance of a host egg by females with different levels of ovipositional experience. The level of experience was designated using the standard oviposition sequence: (1) host contact (C); (2) host examination (E); (3) drilling (D); (4) full insertion (FI); and (5) oviposition (O). Each treatment consisted of a single experience level, but together these consituted a qualitative behavioural continuum of oviposition experience from naive (N) to experienced wasps. We found that host experience by adult T. australicum females can modify their behaviour. Mean duration of host finding was: N = C > E = D > FI = O. Mean duration of host examination and full insertion were: N = C > E = D = FI = O. Drilling was constant for all experience levels. Experience in drilling of the chorion during the previous host-exposure process represents a critical experience for a female and results in efficient handling and more ready acceptance of a subsequently encountered host egg. 相似文献
9.
10.
2015年以来,在简政放权的大环境下,我国医疗技术管理面临着从重审批的分级分类管理向重监管转型的挑战和机遇,亟需探索建立更加科学合理的医疗技术管理体系。使用医疗技术评估的科学工具和手段是在医疗技术管理领域国际通行的理念和做法。本文梳理了我国医疗技术管理政策沿革,介绍了国际典型代表英国医疗技术管理的过程和方法,并为完善我国医疗技术管理提供了几条政策建议。 相似文献