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71.
Zoe Barclay Louise Dickson Derek Robertson Melanie Johnson Pamela Holland Roberta Rosie Liting Sun Helen Jerina Eve Lutz Sue Fleetwood-Walker Rory Mitchell 《Cellular signalling》2013,25(4):814-821
The 5-HT2A receptor (5-HT2AR) is implicated in psychotropic changes within the central nervous system (CNS). A number of polymorphisms have been reported in the 5-HT2AR gene; one of these results in a non-synonymous change, H452Y, in the carboxy-terminal tail of the receptor protein. The minor allele (9% occurrence) has been statistically associated with CNS dysfunction such as impaired memory processing and resistance to neuroleptic treatment in schizophrenic patients. We investigated the impact of H452Y mutation of the 5-HT2AR expressed in COS7 cells on distinctly coupled intracellular signalling pathways from the receptor, focusing on the heterotrimeric G protein-independent phospholipase D (PLD) pathway, compared to the conventional Gq/11-linked phospholipase C (PLC) pathway. The H452Y mutation selectively attenuated PLD signalling, which as in the wild-type receptor, was mediated by a molecular complex involving PLD1 docked to the receptor's carboxy-terminal tail domain. Co-immunoprecipitation and GST-fusion protein experiments revealed that the H452Y mutation selectively reduced PLD1 binding to the receptor. Experiments with blocking peptides to mimic short sections of the 5-HT2AR tail sequence revealed that the peptide spanning residue 452 strongly reduced PLD but not PLC responses of the receptor. Similar observations were made when assessing both PLD responses and PLD-dependent cellular proliferation elicited by activation of 5-HT2ARs natively expressed in MCF-7 cells. Overall these findings indicate that the H452Y polymorphic variant of the 5-HT2AR displays selective disruption of its PLD signalling pathway. This may potentially play a role in the CNS dysfunction associated with the H452Y allele of the 5-HT2AR. 相似文献
72.
Sue Savage-Rumbaugh Kanzi Wamba Panbanisha Wamba Nyota Wamba 《Journal of applied animal welfare science : JAAWS》2013,16(1):7-19
Accurately determining the proper captive environment for apes requires adequately assessing the psychological similarities between apes and humans. Scientists currently believe apes lack mental complexity (Millikan, 2006), raising questions concerning the evolution of human culture from ape-like societies (Tomasello, 1999). A long-term cultural study with bonobos suggests less intellectual divergence from humans than currently postulated (Savage-Rumbaugh, 2005). Because humans view apes as mentally limited, some current captive environments may appear idyllic while offering only an illusion of appropriate care, derived from a simplistic view of what apes are, rather than what they might be. This perception of apes determines their handling, which determines their mental development, which perpetuates the prevailing perception. Only breaking this cycle will allow the current perception of apes to change. Their usual captive environment limits any demonstration of culture. However, the bonobo study reveals what ape culture can become, which should affect future welfare considerations for at least those species genetically close to humans (bonobos and chimpanzees). Development of a languaged bonobo culture allows these nonhuman animals to provide their own responses regarding adequate ape welfare. 相似文献
73.
Holly A. Little Ekaterina Papadopoulou Sue A. Hammar Rebecca Grumet 《Sexual plant reproduction》2007,20(3):123-136
Sexual diversity expressed by Curcurbitaceae species is a primary example of developmental plasticity in plants. Ethylene,
which promotes femaleness (carpel development), plays a key role in sex determination. We sought to determine the critical
location for ethylene perception in developing floral primodia. The dominant negative Arabidopsis ethylene response mutant
gene, etr1-1, was introduced into melon (Cucumis melo L.) plants under control of the constitutive cauliflower mosaic virus (CaMV) 35S promoter, or floral-targeted Apetela3 (AP3) and Crab’s Claw (CRC) promoters, which in Arabidopsis, promote expression in petal and stamen, and carpel and nectary primordia, respectively.
Based on effects of exogenous ethylene, it was predicted that inhibition of ethylene perception by carpel primordia would
inhibit carpel development. Constitutive expression of etr1-1 caused several phenotypes associated with ethylene insensitivity, verifying that etr1-1 inhibits ethylene perception in the heterologous melon system. Carpel-bearing bud production was essentially abolished in
35S::etr1-1 melons, providing direct demonstration of the requirement for ethylene perception for carpel development. CRC::etr1-1 plants, however, showed enhanced femaleness as manifested by earlier and increased number of carpel-bearing buds, and production
of female (rather than bisexual) buds. Despite increased carpel-bearing bud formation, a greater proportion of the CRC::etr1-1 carpel-bearing buds aborted before anthesis. AP3::etr1-1 plants showed increased maleness by nearly exclusive staminate flower production, and poorly developed carpels in the rare
bisexual flowers. These results indicate that ethylene perception by the stamen (or petal) primordia plays a critical role
in promoting carpel development at the time of sex determination, while ethylene perception by the carpel is important for
maturation of carpel-bearing flowers to anthesis. 相似文献
74.
The interactive effect of grazing and soil resources on plant species richness and coexistence has been predicted to vary
across spatial scales. When resources are not limiting, grazing should reduce competitive effects and increase colonisation
and richness at fine scales. However, at broad scales richness is predicted to decline due to loss of grazing intolerant species.
We examined these hypotheses in grasslands of southern Australia that varied in resources and ungulate grazing intensity since
farming commenced 170 years ago. Fine-scale species richness was slightly greater in more intensively grazed upper slope sites
with high nutrients but low water supply compared to those that were moderately grazed, largely due to a greater abundance
of exotic species. At broader scales, exotic species richness declined with increasing grazing intensity whether nutrients
or water supply were low or high. Native species richness declined at all scales in response to increasing grazing intensity
and greater resource supply. Grazing also reduced fine-scale heterogeneity in native species richness and although exotics
were also characterised by greater heterogeneity at fine scales, grazing effects varied across scales. In these grasslands
patterns of plant species richness did not match predictions at all scales and this is likely to be due to differing responses
of native and exotic species and their relative abundance in the regional species pool. Over the past 170 years intolerant
native species have been eliminated from areas that are continually and heavily grazed, whereas transient, light grazing increases
richness of both exotics and natives. The results support the observation that the processes and scales at which they operate
differ between coevolved ungulate—grassland systems and those in transition due to recent invasion of herbivores and associated
plant species. 相似文献
75.
Richard M. Smith Richard H. A. Baker Chris P. Malumphy Sue Hockland Roger P. Hammon Joe C. Ostoj‐Starzewski Dominique W. Collins 《Agricultural and Forest Entomology》2007,9(4):307-326
1 An appraisal of non‐native invertebrate plant pest establishments in Great Britain, between 1970 and 2004, was carried out to improve our understanding of current invasion processes by non‐native plant pests, and to assist national strategies in managing the risks they pose. 2 A total of 164 establishments, comprising 50 natural colonists and 114 human‐assisted introductions, were recorded across 13 major taxonomic groups. 3 The mean rate of establishment was 22.1 species per 5‐year period: 19.1 and 3.0 species outside and inside protected cultivation, respectively. Despite the continuing rapid growth in international trade and a general perception that rates of pest invasions are accelerating, no significant temporal trends in the rate of establishments in Great Britain were detected, either for natural colonists or human‐assisted introductions, or for pests of plants grown indoors or outside. 4 The plant trade, particularly in ornamental plants, accounted for nearly 90% of human‐assisted introductions; apiculture, biological control, timber imports, transport stowaways and intentional releases each contributed less than 5%. Only eight (4.9%) of the establishments could be considered as having no direct potential economic impact because all other species have been recorded as feeding on cultivated plants. A greater proportion of establishments by both natural colonists and human‐assisted introductions occurred on non‐native, woody plants. 5 The present study confirms previous work in other European countries that highlight the predominant role of the ornamental plant trade in introducing new plant pests to the European continent, mainly from Asia and North America. 相似文献
76.
77.
—Rat pineal serotonin N—acetyltransferase activity increases 30–70-fold at night in the dark and then decreases rapidly when animals are exposed to light. Activity of the enzyme is also stimulated by l -norepinephrine in organ culture. When homogenates of glands stimulated by dark in vivo or NE in vitro are incubated at 37°C, enzyme activity will also rapidly decrease. This decrease can be prevented by one of the cosubstrates of the enzyme, acetyl–CoA. Protection can also be conferred by cysteamine (β-mercaptoethylamine, HS–CH2–CH2–NH2) which is the terminal portion of the CoA molecule. This protection mechanism could be involved in the physiological control of enzyme activity. 相似文献
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80.
S ummary . Some common soil bacteria have been shown to tolerate the presence of chlorinated hydrocarbon fumigants. Several of these bacteria indicated an ability to utilize the chemicals as carbon or energy sources. The breakdown of these fumigants may yield compounds either beneficial or detrimental to plants grown in treated soil. Such information is critical to plant disease control since these chemicals are used for the control of plant pathogens, primarily nematodes. It is suggested that the side effects of soil treatment by which plants are stimulated in their growth is a direct consequence of enhanced beneficial microbial activity. 相似文献