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61.
Citizen science is proving to be an effective tool in tracking the rapid pace at which our environment is changing over large geographic areas. It is becoming increasingly popular, in places such as North America and some European countries, to engage members of the general public and school pupils in the collection of scientific data to support long-term environmental monitoring. Participants in such schemes are generally volunteers and are referred to as citizen scientists. The Christmas bird count in the US is one of the worlds longest running citizen science projects whereby volunteers have been collecting data on birds on a specific day since 1900. Similar volunteer networks in Ireland have been in existence since the 1960s and were established to monitor the number and diversity of birds throughout the country. More recently, initiatives such as Greenwave (2006) and Nature Watch (2009) invite school children and members of the general public respectively, to record phenology data from a range of common species of plant, insect and bird. In addition, the Irish butterfly and bumblebee monitoring schemes engage volunteers to record data on sightings of these species. The primary purpose of all of these networks is to collect data by which to monitor changes in wildlife development and diversity, and in the case of Greenwave to involve children in hands-on, inquiry-based science. Together these various networks help raise awareness of key environmental issues, such as climate change and loss of biodiversity, while at the same time promote development of scientific skills among the general population. In addition, they provide valuable scientific data by which to track environmental change. Here we examine the role of citizen science in monitoring biodiversity in Ireland and conclude that some of the data collected in these networks can be used to fulfil Ireland’s statutory obligations for nature conservation. In addition, a bee thought previously to be extinct has been rediscovered and a range expansion of a different bee has been confirmed. However, it also became apparent that some of the networks play more of an educational than a scientific role. Furthermore, we draw on experience from a range of citizen science projects to make recommendations on how best to establish new citizen science projects in Ireland and strengthen existing ones.  相似文献   
62.
Redesigning the hydrophobic core of a four-helix-bundle protein.   总被引:2,自引:11,他引:2       下载免费PDF全文
Rationally redesigned variants of the 4-helix-bundle protein Rop are described. The novel proteins have simplified, repacked, hydrophobic cores and yet reproduce the structure and native-like physical properties of the wild-type protein. The repacked proteins have been characterized thermodynamically and their equilibrium and kinetic thermal and chemical unfolding properties are compared with those of wild-type Rop. The equilibrium stability of the repacked proteins to thermal denaturation is enhanced relative to that of the wild-type protein. The rate of chemically induced folding and unfolding of wild-type Rop is extremely slow when compared with other small proteins. Interestingly, although the repacked proteins are more thermally stable than the wild type, their rates of chemically induced folding and unfolding are greatly increased in comparison to wild type. Perhaps as a consequence of this, their equilibrium stabilities to chemical denaturants are slightly reduced in comparison to the wild type.  相似文献   
63.
The benzodiazepines, Ro 5-4864, diazepam, clonazepam, and also PK-11195, inhibited, at micromolar concentrations, the proliferation of rat C6 glioma and mouse neuro-2A neuroblastoma cells in culture. The cells possessed high levels of "peripheral-type" high-affinity benzodiazepine binding sites as judged by binding assays and displacement potencies. However, the different potencies and specificities of compounds for the antiproliferative actions and binding affinities for the binding site suggest that the antiproliferative actions were not mediated through the peripheral-type binding site. In support of this, these compounds have also been shown to inhibit proliferation of some nonneuronal cultured cell lines, e.g., mouse SP2/O-Ag 14 hybridoma and rat NCTC epithelial cells, which have no detectable high-affinity peripheral-type benzodiazepine binding sites.  相似文献   
64.
The chemical composition of surface waters of two Dutch moorland pools and of incident precipitation, was monitored from 1982 to 1990. For this period, sulfur and water budgets were calculated using a hydrochemical model developed for well-mixed non-stratifying lakes. Total atmospheric deposition of S decreased significantly after 1986 at both locations. A model describing the sulfur budget in terms of input, output and reduction/oxidation processes predicted a fast decrease of pool water SO4 2− concentrations after a decrease of atmospheric input. However, SO4 2− concentrations in the surface water was lowered only slightly or remained constant. Apparently a source within the lake caused the unexpectedly high SO4 2− concentrations. The possible supply of SO4 2− from the sediment through regulation by (K-)Al-SO4 containing minerals or desorption of SO4 2− from positively charged surfaces in the sediment was evaluated. Solubility calculations of pore water with respect to alunite, basaluminite and jurbanite indicated that SO4 2− concentration was not regulated by these minerals. It is suggested here (1) that desorption of SO4 2− from peaty sediments may account for the estimated SO4 2− supply provided that the adsorption complex is periodically recharged by partial oxidation of the upper bottom sediments and (2) that because of exposure of a part of the pool bottom to the atmosphere during dry summers and subsequent oxidation of reduced S, the amount of SO4 2− may be provided which complements the decreasing depositional SO4 2− input. In future research these two mechanisms need to be investigated.  相似文献   
65.
66.
Organisms are projected to shift their distribution ranges under climate change. The typical way to assess range shifts is by species distribution models (SDMs), which predict species’ responses to climate based solely on projected climatic suitability. However, life history traits can impact species’ responses to shifting habitat suitability. Additionally, it remains unclear if differences in vital rates across populations within a species can offset or exacerbate the effects of predicted changes in climatic suitability on population viability. In order to obtain a fuller understanding of the response of one species to projected climatic changes, we coupled demographic processes with predicted changes in suitable habitat for the monocarpic thistle Carlina vulgaris across northern Europe. We first developed a life history model with species‐specific average fecundity and survival rates and linked it to a SDM that predicted changes in habitat suitability through time with changes in climatic variables. We then varied the demographic parameters based upon observed vital rates of local populations from a translocation experiment. Despite the fact that the SDM alone predicted C. vulgaris to be a climate ‘winner’ overall, coupling the model with changes in demography and small‐scale habitat suitability resulted in a matrix of stable, declining, and increasing patches. For populations predicted to experience declines or increases in abundance due to changes in habitat suitability, altered fecundity and survival rates can reverse projected population trends.  相似文献   
67.
The design of protein–peptide interactions has a wide array of practical applications and also reveals insight into the basis for molecular recognition. Here, we present the redesign of a tetratricopeptide repeat (TPR) protein scaffold, along with its corresponding peptide ligand. We show that the binding properties of these protein–peptide pairs can be understood, quantitatively, using straightforward chemical considerations. The recognition pairs we have developed are also practically useful for the specific identification of tagged proteins. We demonstrate the facile replacement of these proteins, which we have termed T‐Mods (TPR‐based recognition module), for antibodies in both detection and purification applications. The new protein–peptide pair has a dissociation constant that is weaker than typical antibody–antigen interactions, yet the recognition pair is highly specific and we have shown that this affinity is sufficient for both Western blotting and affinity purification. Moreover, we demonstrate that this more moderate affinity is actually advantageous for purification applications, because extremely harsh conditions are not required to dissociate the T‐Mod‐peptide interaction. The results we present are important, not only because they represent a successful application of protein design but also because they help define the properties that should be sought in other scaffolds that are being developed as antibody replacements.  相似文献   
68.
Extracellular matrix signaling via integrin receptors is important for smooth muscle cell (SMC) differentiation during vasculogenesis and for phenotypic modulation of SMCs during atherosclerosis. We previously reported that the noncatalytic carboxyl-terminal protein binding domain of focal adhesion kinase (FAK) is expressed as a separate protein termed FAK-related nonkinase (FRNK) and that ectopic expression of FRNK can attenuate FAK activity and integrin-dependent signaling (A. Richardson and J. T. Parsons, Nature 380:538-540, 1996). Herein we report that in contrast to FAK, which is expressed ubiquitously, FRNK is expressed selectively in SMCs, with particularly high levels observed in conduit blood vessels. FRNK expression was low during embryonic development, was significantly upregulated in the postnatal period, and returned to low but detectable levels in adult tissues. FRNK expression was also dramatically upregulated following balloon-induced carotid artery injury. In cultured rat aortic smooth muscle cells, overexpression of FRNK attenuated platelet-derived growth factor (PDGF)-BB-induced migration and also dramatically inhibited [(3)H]thymidine incorporation upon stimulation with PDGF-BB or 10% serum. These effects were concomitant with a reduction in SMC proliferation. Taken together, these data indicate that FRNK acts as an endogenous inhibitor of FAK signaling in SMCs. Furthermore, increased FRNK expression following vascular injury or during development may alter the SMC phenotype by negatively regulating proliferative and migratory signals.  相似文献   
69.
Previously, we identified five active phosphatidylinositol ether lipid analogues (PIAs) that target the pleckstrin homology domain of Akt and selectively induce apoptosis in cancer cells with high levels of Akt activity. To examine specificity, PIAs were screened against a panel of 29 purified kinases. No kinase was inhibited, but one isoform of p38, p38alpha, was uniformly activated 2-fold. Molecular modeling of p38alpha revealed the presence of two regions that could interact with PIAs, one in the activation loop and a heretofore unappreciated region in the upper lobe that resembles a pleckstrin homology domain. In cells, two phases of activation were observed, an early phase that was independent of the upstream kinase MKK3/6 and inhibited by the p38 inhibitor SB203580 and a latter phase that was coincident with MKK3/6 activation. In short term xenograft experiments that employed immunohistochemistry and immunoblotting, PIA administration increased phosphorylation of p38 but not MKK3/6 in tumors in a statistically significant manner. Although PIAs rapidly activated p38 with similar time and dose dependence as Akt inhibition, p38 activation and Akt inhibition were independent events induced by PIAs. Using SB203580 or p38alpha(-/-) cells, we showed that p38alpha is not required for PIA-induced apoptosis but is required for H(2)O(2)- and anisomycin-induced apoptosis. Nonetheless, activation of p38a contributes to PIA-induced apoptosis, because reconstitution of p38a into p38alpha(-/-) cells increased apoptosis. These studies indicate that p38alpha is activated by PIAs through a novel mechanism and show that p38alpha activation contributes to PIA-induced cell death. Independent modulation of Akt and p38alpha could account for the profound cytotoxicity of PIAs.  相似文献   
70.
Characterization of the various microbial populations present in exoelectrogenic biofilms provides insight into the processes required to convert complex organic matter in wastewater streams into electrical current in bioelectrochemical systems (BESs). Analysis of the community profiles of exoelectrogenic microbial consortia in BESs fed different substrates gives a clearer picture of the different microbial populations present in these exoelectrogenic biofilms. Rapid utilization of fermentation end products by exoelectrogens (typically Geobacter species) relieves feedback inhibition for the fermentative consortia, allowing for rapid metabolism of organics. Identification of specific syntrophic processes and the communities characteristic of these anodic biofilms will be a valuable aid in improving the performance of BESs.  相似文献   
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