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Although organizations use a variety of interventions to improve group functioning, getting people to work effectively with each other remains challenging. Because the presence of a dog has been shown to have positive effects on mood and dyadic interaction, we expected that the presence of a companion dog would also have positive effects on people in work groups. One reason for this is that a companion dog is likely to elevate positive emotions, which often promote prosocial behavior. In study 1 (n = 120) and study 2 (n = 120), participants were randomly assigned to either a dogpresent or dog-absent four-person group. Three friendly companion dogs were randomly assigned to the dog-present groups; only one dog at a time was used during any given experimental session. In study 1, groups worked on an interactive problem-solving task; participants in the dog-present group displayed more verbal cohesion, physical intimacy, and cooperation. Study 2 was identical except that participants worked on a decision-making task requiring less interaction; participants in the dog-present condition displayed more verbal cohesion and physical intimacy and gave higher ratings of trustworthiness to fellow group members. In study 3, we examined behavioral indicators of positive emotions in dog-present and dog-absent groups. Naïve observers (n = 160) rated silent, 40-second video clips of interaction in groups where either a dog was (1) present but not visible or (2) not present. Behavior in dog-present groups was rated as more cooperative, comfortable, friendly, active, enthusiastic, and attentive. We discuss areas for future research and implications of our findings for work and educational settings.  相似文献   
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Ganglioside stimulated neurite outgrowth may be due to gangliosidebinding to membrane proteins or to intercalation into the membrane.To test that ganglioside binding proteins could be found onneuronal surfaces, antiidiotypic ganglioside monoclonal antibodies(AIG mAbs) were generated to mimic the biological propertiesof the GM1 ganglioside. The AIG mAbs were identified by theirability to bind to a known GM1 binding protein, the ß-subunit of cholera toxin. For the two AIG mAbs studied, AIG5 andAIG20, binding to ß-CT was blocked most strongly byGM1. This data also suggests that AIG5 and AIG20 mimic differentbut overlapping epitopes of the ganglioside GM1. Western blottingand immunoprecipitation of mammalian tissues reveals four potentialganglioside binding proteins of molecular weight 93, 66, 57,and 45 kDa. Immunocytochemistry demonstrates neuronal surfacelabel with the AIG mAbs, which suggests that gangliosides, enrichedon the neuronal surface membrane, are co-localized with putativeganglioside binding proteins. In bioassays, the AIG mAbs promoteneuronal sprouting. This shows that these antibodies can beused to study the biological effects of ganglioside bindingto neuronal surface proteins, and the role of gangliosides inthe activation of neurite outgrowth. agonist antibody anti-idiotypic antibody gangliosides ganglioside binding proteins  相似文献   
65.
Complex ecological pressures affect the social dynamics of many primate species, but it is unclear how they affect primate speciation. Molecular tools are often used to answer questions about the evolutionary histories and social systems of primates. Mitochondrial DNA (mtDNA), in particular, is frequently used to answer many of these questions, but because it is passed from mothers to offspring it reveals only the histories of females. In many species, including chimpanzees, females generally disperse from their natal groups while males are philopatric, and thus differences in dispersal patterns likely leave different signatures in the genome. We previously analyzed samples from 187 unrelated male and female chimpanzees in Nigeria and Cameroon using 21 autosomal microsatellites and mtDNA sequences. Here, we examine the contributions of males and females in shaping the genetic history of these chimpanzees by genotyping a subset of 56 males at 12 Y-chromosome microsatellites. We found that Y-chromosome population structure differed from the results of analysis of mtDNA haplotypes. The results also revealed that males in rainforest habitats (Guinean and Congolian rainforests) are more closely related to one another than those inhabiting the savanna-woodland mosaic ecotone in central Cameroon. In contrast, the pattern of female relatedness did not differ across habitats. We hypothesize that these differences in population structure and patterns of relatedness among males in different habitat types may be due to differences in the community dynamics of chimpanzees in the ecotone vs. rainforests, and that these factors contribute to making Cameroon an engine of diversification for chimpanzees. Broadly, these results demonstrate the importance of habitat variation in shaping social systems, population genetics, and primate speciation.  相似文献   
66.
Vascular endothelial growth factor-C (VEGF-C) is a secreted growth factor essential for lymphangiogenesis. VEGF-C functions in both physiological and pathological lymphangiogenesis, particularly in tumor metastasis, making it an attractive therapeutic target. Members of two families of cell surface receptors transduce VEGF-C signals: neuropilin-2 (Nrp2) and VEGF-receptor (VEGFR)-2/3. Nrp2 is a promising target for inhibition because it is highly expressed in lymphatic vessels. Here we describe a microplate-based assay for discovery of VEGF-C/Nrp2 inhibitors. We optimize this assay for use in screening an inhibitor library and identify three novel Nrp2/VEGF-C binding inhibitors from the National Institutes of Health (NIH) Clinical Collection small molecule library.  相似文献   
67.
rap-1A, an anti-oncogene-encoded protein, is aras-p21-like protein whose sequence is over 80% homologous to p21 and which interacts with the same intracellular target proteins and is activated by the same mechanisms as p21, e.g., by binding GTP in place of GDP. Both interact with effector proteins in the same region, involving residues 32–47. However, activated rap-1A blocks the mitogenic signal transducing effects of p21. Optimal sequence alignment of p21 and rap-1A shows two insertions of rap-1A atras positions 120 and 138. We have constructed the three-dimensional structure of rap-1A bound to GTP by using the energy-minimized three-dimensional structure ofras-p21 as the basis for the modeling using a stepwise procedure in which identical and homologous amino acid residues in rap-1A are assumed to adopt the same conformation as the corresponding residues in p21. Side-chain conformations for homologous and nonhomologous residues are generated in conformations that are as close as possible to those of the corresponding side chains in p21. The entire structure has been subjected to a nested series of energy minimizations. The final predicted structure has an overall backbone deviation of 0.7 å from that ofras-p21. The effector binding domains from residues 32–47 are identical in both proteins (except for different side chains of different residues at position 45). A major difference occurs in the insertion region at residue 120. This region is in the middle of another effector loop of the p21 protein involving residues 115–126. Differences in sequence and structure in this region may contribute to the differences in cellular functions of these two proteins.  相似文献   
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Behavioral flexibility, including an ability to modify feeding behavior, is a key trait enabling primates to survive in forest fragments. In human-dominated landscapes, unprotected forest fragments can become progressively degraded, and may be cleared entirely, challenging the capacity of primates to adjust to the changes. We examined responses of wild chimpanzees (Pan troglodytes schweinfurthii) to major habitat change: that is, clearance of forest fragments for agriculture. Over 7 years, fragments in Bulindi, Uganda, were reduced in size by 80%. We compared the chimpanzees’ diet at the start and end of this period of rapid deforestation, using data derived mainly from fecal analysis. Similar to other long-term study populations, chimpanzees in Bulindi have a diverse diet comprising over 169 plant foods. However, extensive deforestation seemed to impact their feeding ecology. Dietary changes after fragment clearance included reduced overall frugivory, reduced intake of figs (Ficus spp.; formerly a dietary “staple” for these chimpanzees), and reduced variety of fruits in fecal samples. Nevertheless, the magnitude of most changes was remarkably minor given the extent of forest loss. Agricultural fruits increased in dietary importance, with crops accounting for a greater proportion of fruits in fecal samples after deforestation. In particular, cultivated jackfruit (Artocarpus heterophyllus) became a “staple” food for the chimpanzees but was scarcely eaten before fragment clearance. Crops offer some nutritional benefits for primates, being high in carbohydrate energy and low in hard-to-digest fiber. Thus, crop feeding may have offset foraging costs associated with loss of wild foods and reduced overall frugivory for the chimpanzees. The adaptability of many primates offers hope for their conservation in fragmented, rural landscapes. However, long-term data are needed to establish whether potential benefits (i.e. energetic, reproductive) of foraging in agricultural matrix habitats outweigh fitness costs from anthropogenic mortality risk for chimpanzees and other adaptable primates.  相似文献   
70.
Yellow and red-violet betalain plant pigments are restricted to several families in the order Caryophyllales, where betacyanins play analogous biological roles to anthocyanins. The initial step in betalain biosynthesis is the hydroxylation of tyrosine to form L-DOPA. Using gene expression experiments in beets, yeast, and Arabidopsis, along with HPLC/MS analysis, the present study shows that two novel cytochrome P450 (CYP450) enzymes, CYP76AD6 and CYP76AD5, and the previously described CYP76AD1 can perform this initial step. Co-expressing these CYP450s with DOPA 4,5-dioxygenase in yeast, and overexpression of these CYP450s in yellow beets show that CYP76AD1 efficiently uses L-DOPA leading to red betacyanins while CYP76AD6 and CYP76AD5 lack this activity. Furthermore, CYP76AD1 can complement yellow beetroots to red while CYP76AD6 and CYP76AD5 cannot. Therefore CYP76AD1 uniquely performs the beet R locus function and beets appear to be genetically redundant for tyrosine hydroxylation. These new functional data and ancestral character state reconstructions indicate that tyrosine hydroxylation alone was the most likely ancestral function of the CYP76AD alpha and beta groups and the ability to convert L-DOPA to cyclo-DOPA evolved later in the alpha group.  相似文献   
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