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281.
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Marie Lacan Christine Keyser Eric Crubézy Bertrand Ludes 《Cellular and molecular life sciences : CMLS》2013,70(14):2473-2487
Understanding the peopling history of Europe is crucial to comprehend the origins of modern populations. Of course, the analysis of current genetic data offers several explanations about human migration patterns which occurred on this continent, but it fails to explain precisely the impact of each demographic event. In this context, direct access to the DNA of ancient specimens allows the overcoming of recent demographic phenomena, which probably highly modified the constitution of the current European gene pool. In recent years, several DNA studies have been successfully conducted from ancient human remains thanks to the improvement of molecular techniques. They have brought new fundamental information on the peopling of Europe and allowed us to refine our understanding of European prehistory. In this review, we will detail all the ancient DNA studies performed to date on ancient European DNA from the Middle Paleolithic to the beginning of the protohistoric period. 相似文献
283.
S. Rapoport E. C. G. Hofmann Anna Ghiretti-Magaldi 《Cellular and molecular life sciences : CMLS》1958,14(5):169-170
Riassunto Le attività citocroma ossidasica, succino-deidrogenasica, DPNH e TPNH cit. c riduttasica sono state studiate in omogenati e frazioni mitocondriali e microsomiali di uova vergini e fecondate diParacentrotus lividus. I mitocondri contengono tutta l'attività citocromossidasica e succinodeidrogenasica, mentre i microsomi solo una metà della attività DPNH cit. c riduttasica totale. Spettri differenziali hanno rivelato la presenza, nei microsomi, di un citocromo avente una banda a 428–430 mµ. 相似文献
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Anna Rising Mona Widhe Jan Johansson My Hedhammar 《Cellular and molecular life sciences : CMLS》2011,68(2):169-184
Spider dragline silk is an outstanding material made up of unique proteins—spidroins. Analysis of the amino acid sequences
of full-length spidroins reveals a tripartite composition: an N-terminal non-repetitive domain, a highly repetitive central
part composed of approximately 100 polyalanine/glycine rich co-segments and a C-terminal non-repetitive domain. Recent molecular
data on the terminal domains suggest that these have different functions. The composite nature of spidroins allows for recombinant
production of individual and combined regions. Miniaturized spidroins designed by linking the terminal domains with a limited
number of repetitive segments recapitulate the properties of native spidroins to a surprisingly large extent, provided that
they are produced and isolated in a manner that retains water solubility until fibre formation is triggered. Biocompatibility
studies in cell culture or in vivo of native and recombinant spider silk indicate that they are surprisingly well tolerated,
suggesting that recombinant spider silk has potential for biomedical applications. 相似文献
286.
Anna Staszewska‐Bystrova 《Journal of forecasting》2011,30(8):721-735
The problem of forecasting from vector autoregressive models has attracted considerable attention in the literature. The most popular non‐Bayesian approaches use either asymptotic approximations or bootstrapping to evaluate the uncertainty associated with the forecast. The practice in the empirical literature has been to assess the uncertainty of multi‐step forecasts by connecting the intervals constructed for individual forecast periods. This paper proposes a bootstrap method of constructing prediction bands for forecast paths. The bands are constructed from forecast paths obtained in bootstrap replications using an optimization procedure to find the envelope of the most concentrated paths. From extensive Monte Carlo study, it is found that the proposed method provides more accurate assessment of predictive uncertainty from the vector autoregressive model than its competitors. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
287.
The objective of this article is to uncover benefits and risks of Integrated Product Service Offering (IPSO) in a systematic manner. To do so, it adopts an explorative longitudinal in-depth case study (development of an IPSO based on a new technology) and adds insights to the existing literature. The article first proposes a theoretical and generic framework termed the PCP (Provider - Customer - Product) triangle with associated information flow and uncertainty. Second, various types of benefits and risks are presented based on the framework. Among others, the benefit of keeping IPR (Intellectual Property Rights) with the provider and the risk of regulation change are new findings from the case study. In addition, the case study reveals that IPSO is regarded as a positive contributor to innovation. Applying the framework and classification of benefits and risks as norms to other cases has yet to be done for verification. However, the framework contributes scientifically to a better understanding of the benefits and risks of IPSO. In addition, this framework is advantageous with its easiness to understand, which contributes practically to the dissemination of IPS0 insight to industry. 相似文献
288.
This paper investigates the extent of overseas migration by British chemists over the period 1887–1971. Notwithstanding the ‘brain drain’ alarms of the 1960s, overseas employment was characteristic of some 19% of British chemists’ careers throughout our period, though its nature changed considerably. Our study examines the overseas employment histories of four cohorts of members of the [Royal] Institute of Chemistry in the ‘Chemists’ Database’ at the Open University. Those employed abroad were not only highly qualified but also both geographically mobile and occupationally versatile. Over the period, the pattern of chemists’ migration was broadly similar to that of British migration trends more generally. Except in the interwar years, chemists’ rate of migration was relatively constant. However, the length of time they spent abroad declined markedly over the period: long-term migration became less characteristic than short-term overseas employment for purposes of career development. From the late nineteenth century, British chemists staffed the Empire, but also found employment in the expanding US economy. After 1945, chemists’ destinations shifted more markedly towards North America, including Canada, and later also to Europe. Our work thus provides a new perspective on the dynamics of scientists’ migration and contributes to studies on the brain drain. 相似文献
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