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1.
Here we present an analytical technique for the measurement and evaluation of changes in chronologically sequenced assemblages. To illustrate the method, we studied the cultural evolution of European cooking as revealed in seven cook books dispersed over the past 800 years. We investigated if changes in the set of commonly used ingredients were mainly gradual or subject to fashion fluctuations. Applying our method to the data from the cook books revealed that overall, there is a clear continuity in cooking over the ages – cooking is knowledge that is passed down through generations, not something (re-)invented by each generation on its own. Looking at three main categories of ingredients separately (spices, animal products and vegetables), however, disclosed that all ingredients do not change according to the same pattern. While choice of animal products was very conservative, changing completely sequentially, changes in the choices of spices, but also of vegetables, were more unbounded. We hypothesize that this may be due a combination of fashion fluctuations and changes in availability due to contact with the Americas during our study time period. The presented method is also usable on other assemblage type data, and can thus be of utility for analyzing sequential archaeological data from the same area or other similarly organized material. 相似文献
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Sven Kurbel 《BioEssays : news and reviews in molecular, cellular and developmental biology》2020,42(10):2000056
This paper discusses possible mechanisms that might lead to misinterpretations of collected data and makes new evidence-based medicine (EBM) recommendations to oppose the previously accepted preventive measures, or treatment options. It is focused on the danger of the “red meat” consumption, and the question whether eating pungent food is good or bad for our health and finally whether the “bad luck” concept of getting several cancer types is valid or not. These three topics got and still have significant media attention. Several mechanisms are proposed as possible causes of these apparent conflicts. Some of them have already been recognized but sadly remained less known to medical readers and also to the general population. Also see the video abstract here https://youtu.be/owjoRXrNShA . 相似文献
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Sven Hörstadius 《Development genes and evolution》1923,98(1-2):1-9
Ohne ZusammenfassungDie Untersuchungen wurden an der Zoologischen Station Kristineberg, Schweden, ausgeführt. Es ist mir eine angenehme Pflicht, dem Direktor, Herrn ProfessorHjalmar Théel, und dem Vorstand, Herrn Dr.Hjalmar Östergren, meinen besten Dank auszusprechen. Schließlich richte ich den herzlichsten Dank an Herrn Dr.John Runnström, Stockholm, der mir die Idee der Untersuchung gegeben und mit größtem Interesse und größter Freundlichkeit meine Arbeit geleitet hat. 相似文献
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Recent studies have suggested that ribosomal protein S12 modulates 16S rRNA function and susceptibility to 2-deoxystreptamine aminoglycosides. To study whether the non-restrictive K42R mutation in RpsL affects 2-deoxystreptamine susceptibility in Mycobacterium smegmatis, we studied the drug susceptibility pattern of various mutants with genetic alterations in the 16S rRNA decoding A-site in the context of wild-type and mutant protein S12. RpsL K42R substitution was found not to affect the drug resistance pattern associated with mutational alterations in 16S rRNA H44. 相似文献
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Two large, electron dense heavy-metal complexes were found to bind to crystals of heavy riboflavin synthase. The crystallographic analysis by difference Fourier methods shows that the tungsten cluster compound [(W3O2(O2CCH3)6]2+, which has trigonal symmetry, binds to a site on the 3-fold axis of the protein. The heteropolytungstate compound [NaP5W30O110]14-, which has pentagonal symmetry, binds to a site on the 5-fold axis of the protein. 相似文献
9.
Gunnar ?hlund Per Hedstr?m Sven Norman Catherine L. Hein G?ran Englund 《Proceedings. Biological sciences / The Royal Society》2015,282(1799)
The temperature dependence of predation rates is a key issue for understanding and predicting the responses of ecosystems to climate change. Using a simple mechanistic model, we demonstrate that differences in the relative performances of predator and prey can cause strong threshold effects in the temperature dependence of attack rates. Empirical data on the attack rate of northern pike (Esox lucius) feeding on brown trout (Salmo trutta) confirm this result. Attack rates fell sharply below a threshold temperature of +11°C, which corresponded to a shift in relative performance of pike and brown trout with respect to maximum attack and escape swimming speeds. The average attack speed of pike was an order of magnitude lower than the escape speed of brown trout at 5°C, but approximately equal at temperatures above 11°C. Thresholds in the temperature dependence of ecological rates can create tipping points in the responses of ecosystems to increasing temperatures. Thus, identifying thresholds is crucial when predicting future effects of climate warming. 相似文献
10.
Non-Uniform Sampling has the potential to exploit the optimal resolution of high-field NMR instruments. This is not possible in 3D and 4D NMR experiments when using traditional uniform sampling due to the long overall measurement time. Nominally, uniformly sampled time domain data acquired to a maximum evolution time tmax can be extended to high resolution via a virtual maximum evolution time t*max while extrapolating with linear prediction or iterative soft thresholding (IST). At the high resolution obtainable with extrapolation of US data, however, the accuracy of peak positions is compromised as observed when comparing inter- and intra-residue peaks in a 3D HNCA experiment. However, the accuracy of peak positions is largely improved by spreading the same number of acquired time domain data points non-uniformly over a larger evolution time to an optimal tmax followed by extrapolation to a total t*max and processing the data with an appropriate reconstruction method, such as hmsIST. To explore the optimum value of experimentally measured tmax to be reached non-uniformly with a given number of sampling points we have created test situations of time-equivalent experiments and evaluate sensitivity and accuracy of peak positions. Here we use signal-to-maximum-noise ratio as the decisive measure of sensitivity. We find that both sensitivity and resolution are optimal when PoissonGap sampling to a tmax of about ½*T2 *. Digital resolution is further enhanced by extrapolating the range of acquired time domain data to 2*T2 * but without measuring experimental points beyond ½*T2 *. 相似文献