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171.
Understanding the Organization of Industrial Ecosystems   总被引:1,自引:0,他引:1  
Industrial symbiosis (IS) has been used to describe the physical exchange and shared management of input and output materials by geographically proximate firms. Firms that engage in IS are said to belong to an industrial ecosystem. Symbiosis has been found to be motivated by economic considerations, such as lowering costs for waste disposal, as well as by environmental ones, such as accessing limited water supplies. Communication and trust among managers are thought to play important roles in exchanges; however, empirical studies have not been previously conducted. This study used social network analysis (SNA) to identify the prevalence of industrial symbiosis linkages in Barceloneta, Puerto Rico. The study quantified patterns in various relationships among firms and managers, including formal relations through supply chains, and informal ones through interpersonal interactions. SNA and statistical methods were used to explore how these ties correlate with observed industrial symbiosis activities. IS linkages were found to be less prevalent than product sales among firms and were concentrated among pharmaceutical firms at the core of the regional network. Trust among managers and position in the social hierarchy were found to be correlated with IS but not supply chain links. SNA was useful for examining the organization of different relationships in the industrial ecosystem, but contextual information is still needed to add meaning to its findings.  相似文献   
172.
Approximately 1,000 volunteers assessed the presence of invasive (Carcinus maenas and Hemigrapsus sanguineus) and native crabs within the intertidal zone of seven coastal states of the US, from New Jersey to Maine. Identification of crab species and determination of the gender of the observed crabs was documented at all 52 sites across a 725-km coastal transect. Using quantitative measures of accuracy of data collected by citizen scientists, a significant predictor of a volunteer’s ability was determined and eligibility criteria were set. Students in grade three and seven had the ability to differentiate between species of crabs with over 80% and 95% accuracy, respectively. Determination of gender of the crabs was more challenging and accuracy exceeded 80% for seventh grade students, while 95% accuracy was found for students with at least 2 years of university education. We used the data collected by citizen scientists to create a large-scale standardized database of the distribution and abundance of the native and invasive crabs. Hemigrapsus sanguineus dominated the rocky intertidal zone from Sandy Hook, New Jersey to Boston Harbor, Massachusetts while C. maenas dominated the northern extent of the sampled coastline. A citizen scientist of this monitoring network detected a range expansion of H. sanguineus. We identified obstacles to creating a national monitoring network and proposed recommendations that addressed these issues.  相似文献   
173.
174.
It is widely accepted that there is a considerable gap between the science of conservation biology and the design and execution of biodiversity conservation projects in the field and science is failing to inform the practice of conservation. There are many reasons why this implementation gap exists. A high proportion of papers published in scientific journals by conservation biologists are seldom read outside of the academic world and there are few incentives for academics to convert their science into practice. In turn, field practitioners rarely document their field experiences and experiments in a manner that can meaningfully inform conservation scientists. Issues related to access to scientific literature, scientific relevance in multidisciplinary environments, donor expectations and a lack of critical analysis at all levels of conservation theory and practice are factors that exacerbate the divide. The contexts in which conservation biologists and field practitioners operate are also often highly dissimilar, and each has differing professional responsibilities and expectations that compromise the ability to learn from each other's expertise. Building on recent debate in the literature, and using case studies to illustrate the issues that characterize the divide, this paper draws on the authors' experiences of project management as well as academic research. We identify five key issues related to information exchange: access to scientific literature, levels of scientific literacy, lack of interdisciplinarity, questions of relevance and lack of sharing of conservation-related experiences and suggest new ways of working that could assist in bridging the gap between conservation scientists and field practitioners.  相似文献   
175.
Koenigs–Knorr-type glycosidations of peracylated 2Z-benzoyloxyimino-glycopyranosyl bromides invariably proceed with retention of the Z-geometry. Accordingly, the many β-d-hexosidulose oximes in literature which were prepared in this way and for which the oxime geometry has not been addressed explicitly, are the Z-oximes throughout. By contrast, oximation of β-d-hexopyranosid-2-uloses leads to mixtures of E and Z oximes readily separable and structurally verifiable by 1H and 13C NMR. Configurational assignments rested on comparative evaluation of NMR data of E and Z isomers, and, most notably on an X-ray structural analysis of the pivaloylated isopropyl 2E-benzoyloxyimino-2-deoxy-β-d-arabino-hexopyranoside revealing the unusual 1S51,4B conformation for the pyranoid ring.  相似文献   
176.
Eukaryotic cells rely on a surveillance mechanism, the "Spindle Assembly Checkpoint"SACM in order to ensure accurate chromosome segregation by preventing anaphase initiation until all chromosomes are correctly attached to the mitotic spindle. In different organisms, a mitotic checkpoint complex (MCC) composed of Mad2, Bub3, BubR1/Mad3, and Cdc20 inhibits the anaphase promoting complex (APC/C) to initiate promotion into anaphase. The mechanism of MCC formation and its regulation by the kinetochore are unclear. Here, we constructed dynamical models of MCC formation involving different kinetochore control mechanisms including amplification as well as inhibition effects, and analysed their quantitative properties. In particular, in this system, fast and stable metaphase to anaphase transition can only be triggered when the kinetochore controls the Bub3:BubR1-related reactions; signal amplification and inhibition play a subordinate role. Furthermore, when introducing experimentally determined parameter values into the models analysed here, we found that effective MCC formation is not combined with complete Cdc20 sequestering. Instead, the MCC might bind and completely block the APC/C. The SACM might function by an MCC:APC/C complex rearrangement.  相似文献   
177.
It is well known that Darwin and Wallace came to discover the phenomenon of evolution through a historical approach to the geographical distribution of organisms. Before Darwin, evolution was a mere speculation that could be invoked to explain some facts. Darwin's biogeographical argument for evolution is based largely on three main explanatory hypotheses. The first is that the geographical distribution of organisms is historically informative. The second hypothesis is that long-distance dispersal over barriers is one main force (extinction is the other) that modifies the distribution of organisms. The third of Darwin's biogeographical hypotheses is that the factors that shape the distribution of organisms are mainly historical (large, often global and long temporal scales) rather than ecological (small spatial and short temporal scales). From the time of Darwin until now, a wide spectrum of biogeographical schools have provided new insights that challenge the central role of space, dispersal and history as the main explanatory hypotheses for the distribution of organisms, generating three binary opposites: (1) the spatial dimension of evolution: geographical distribution of organisms as historically informative vs. historically uninformative; (2) the processes that modify the geographical distribution of organisms: dispersal vs. vicariance; and (3) the explanation of geographical distribution: history vs. ecology. We analyse these three binary opposites to show that the components of each are complementary rather than antagonistic approaches to the study of biogeography.  相似文献   
178.
In view of the pressing problem that appears in our region (Asturias, north of Spain) with the residues from the cider production, it was decided to test this kind of material as a co-substrate joint with slaughterhouse waste in a laboratory unit.  相似文献   
179.
The coancestry coefficient, also known as the population structure parameter, is of great interest in population genetics. It can be thought of as the intraclass correlation of pairs of alleles within populations and it can serve as a measure of genetic distance between populations. For a general class of evolutionary models it determines the distribution of allele frequencies among populations. Under more restrictive models it can be regarded as the probability of identity by descent of any pair of alleles at a locus within a random mating population. In this paper we review estimation procedures that use the method of moments or are maximum likelihood under the assumption of normally distributed allele frequencies. We then consider the problem of testing hypotheses about this parameter. In addition to parametric and non-parametric bootstrap tests we present an asymptotically-distributed chi-square test. This test reduces to the contingency-table test for equal sample sizes across populations. Our new test appears to be more powerful than previous tests, especially for loci with multiple alleles. We apply our methods to HapMap SNP data to confirm that the coancestry coefficient for humans is strictly positive.  相似文献   
180.
Ecology and the social sciences   总被引:1,自引:1,他引:0  
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