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981.
982.
Niels Thomas Eriksen Frederik Kier Riisgård William Stuart Gunther Jens Jørgen Lønsmann Iversen 《Journal of applied phycology》2007,19(2):161-174
Growth of the green algae Chlamydomonas reinhardtii and Chlorella sp. in batch cultures was investigated in a novel gas-tight photobioreactor, in which CO2, H2, and N2 were titrated into the gas phase to control medium pH, dissolved oxygen partial pressure, and headspace pressure, respectively.
The exit gas from the reactor was circulated through a loop of tubing and re-introduced into the culture. CO2 uptake was estimated from the addition of CO2 as acidic titrant and O2 evolution was estimated from titration by H2, which was used to reduce O2 over a Pd catalyst. The photosynthetic quotient, PQ, was estimated as the ratio between O2 evolution and CO2 up-take rates. NH4
+, NO2
−, or NO3
− was the final cell density limiting nutrient. Cultures of both algae were, in general, characterised by a nitrogen sufficient
growth phase followed by a nitrogen depleted phase in which starch was the major product. The estimated PQ values were dependent on the level of oxidation of the nitrogen source. The PQ was 1 with NH4
+ as the nitrogen source and 1.3 when NO3
− was the nitrogen source. In cultures grown on all nitrogen sources, the PQ value approached 1 when the nitrogen source was depleted and starch synthesis became dominant, to further increase towards
1.3 over a period of 3–4 days. This latter increase in PQ, which was indicative of production of reduced compounds like lipids, correlated with a simultaneous increase in the degree
of reduction of the biomass. When using the titrations of CO2 and H2 into the reactor headspace to estimate the up-take of CO2, the production of O2, and the PQ, the rate of biomass production could be followed, the stoichiometrical composition of the produced algal biomass could be
estimated, and different growth phases could be identified. 相似文献
983.
Christian Huber Caroline Schulze Manuela Baumgarten 《Biodiversity and Conservation》2007,16(12):3653-3680
The early effects of femel-cutting (removing 20% of the trees) and small scale clear-cutting on ground-living spiders in a
Norway spruce (Picea abies (L.) Karst.) forest in Southern Germany were investigated. The study was carried out as BACIP (before and after, control-impact,
many paired samplings) study: Spiders were sampled during the pre-treatment year, the year of cutting, and the year after
cutting. In total 7101 individuals were sampled, of which 4530 individuals were identified, 4468 were adult and 2633 individuals
were juvenile. We identified 107 species, but a single species, Coelotes terrestris, dominated the control (spruce stand) comprising up to 49% of the total identified individuals. Clear-cutting changed the
species composition in the traps, while the first step in femel-cutting preserved it. The number of individuals of the families
Linyphiidae, Amaurobiidae, Agelenidae and Clubionidae decreased drastically within the 2 years after the clear-cutting, while
the Lycosidae became numerically dominant in the clear-cut stands. The number of individuals with the following characterisation
decreased significantly after clear-cutting: Small (<3.0 mm) and large spiders (>10.5 mm), web builders, ‘forest habitat species’,
species favouring hygrophilic to medium moisture conditions, and preferences to live below ground or in and on the moss layer.
On the other hand, middle-sized spiders, free hunters, ‘open habitat species’, spiders favouring dry conditions or that are
euryoecious, preferring patterns covered by grasses or uncovered patches, increased in number. Clear-cut habitats with dense
spruce regeneration showed a delayed and less pronounced response. With femel-cutting, species composition of ground-living
spider communities may be preserved during the first step of regeneration of mature forest stands. 相似文献
984.
Priv. Doz. Dr. H. G. Baumgarten B. Falck H. Wartenberg 《Cell and tissue research》1970,107(4):479-498
Summary The lower spinal cord including the caudal neurosecretory system of the pike (Esox lucius) was investigated by means of light and electron microscopy and also with the fluorescence histochemical method of Falck and Hillarp for the visualization of monoamines. A system of perikarya displaying a specific green fluorescence of remarkably high intensity is disclosed in the basal part of the ventrolateral and lateral ependymal lining of the central canal. The area corresponding to the upper half of the urophysis has most cells; their number decreases caudally and cranially. A considerable number of their beaded neurites reach the neurosecretory neurons by different routes but are only occasionally present in the actual neurohemal region. An intensely fluorescent dendritic process is sometimes observed terminating with a bulbous enlargement at the ependymal surface in the central canal. Besides small, electron lucid vesicles in the terminal parts of the axons, the neurons contain numerous large dense-core vesicles which can apparently take up and store 5-hydroxydopa (5-OH-dopa) and 5-hydroxydopamine (5-OH-DA). These neurons are thought to be adrenergic and to contain a primary catecholamine, possibly noradrenaline.The varicosities of the adrenergic terminals are repeatedly observed contiguous to some of the neurosecretory axons, the membrane distance at places of contacts generally ranging from 150–200 Å. Another type of nerve terminals that contain only small empty vesicles, also after pretreatment with 5-OH-dopa or 5-OH-DA, are frequent among the neurosecretory neurons. These axons establish synaptic contacts with membrane thickenings on most of the neurosecretory neurons. Thus it seems that the neurosecretory neurons are innervated by neurons morphologically similar to cholinergic neurons and that part of them receive an adrenergic innervation, which supports the view hat the caudal neurosecretory cells do not constitute a functionally homogeneous population.Supported by the Deutsche Forschungsgemeinschaft and the Joachim-Jungius Gesellschaft zur Förderung der Wissenschaften, Hamburg.Supported by the Swedish Natural Research Council (No. 99-35). This work was in part carried out within a research organization sponsored by the Swedish Medical Research Council (Projects No. B70-14X-56-06 and B70-14X-712-05).Supported by the Deutsche Forschungsgemeinschaft and USPHS Research Grant TW 00295-02. 相似文献
985.
Sergio Crespo-Garcia Pamela R. Tsuruda Agnieszka Dejda Rathi D. Ryan Frederik Fournier Shawnta Y. Chaney Frederique Pilon Taner Dogan Gael Cagnone Priyanka Patel Manuel Buscarlet Sonali Dasgupta Gabrielle Girouard Surabhi R. Rao Ariel M. Wilson Robert O’Brien Rachel Juneau Vera Guber Przemyslaw Sapieha 《Cell metabolism》2021,33(4):818-832.e7
986.
Arne P. Raulf Joshua Butke Lukas Menzen Claus Küpper Frederik Großerueschkamp Klaus Gerwert Axel Mosig 《Journal of biophotonics》2021,14(3):e202000385
Infrared spectra obtained from cell or tissue specimen have commonly been observed to involve a significant degree of scattering effects, often Mie scattering, which probably overshadows biochemically relevant spectral information by a nonlinear, nonadditive spectral component in Fourier transform infrared (FTIR) spectroscopic measurements. Correspondingly, many successful machine learning approaches for FTIR spectra have relied on preprocessing procedures that computationally remove the scattering components from an infrared spectrum. We propose an approach to approximate this complex preprocessing function using deep neural networks. As we demonstrate, the resulting model is not just several orders of magnitudes faster, which is important for real-time clinical applications, but also generalizes strongly across different tissue types. Using Bayesian machine learning approaches, our approach unveils model uncertainty that coincides with a band shift in the amide I region that occurs when scattering is removed computationally based on an established physical model. Furthermore, our proposed method overcomes the trade-off between computation time and the corrected spectrum being biased towards an artificial reference spectrum. 相似文献
987.
Cell and Tissue Research - The human tunica dartos has been investigated by light, fluorescence and electron microscopy. It consists of solid bundles of smooth musculature in the subcutis, and... 相似文献
988.
Biogenic monoamines in the cyclostome and lower vertebrate brain 总被引:3,自引:0,他引:3
H G Baumgarten 《Progress in histochemistry and cytochemistry》1972,4(1):1-90
989.
Isabelle Sioen John Van Camp Frederik A. M. Verdonck Nicky Van Thuyne Jan L. Willems Stefaan W. J. De Henauw 《人类与生态风险评估》2007,13(3):632-657
Seafood consumption is related to both favorable health benefits of nutrients and to potential adverse health impacts of chemical contamination. To quantify the magnitude of this dilemma, probabilistic intake assessments can be performed. One step in such a procedure involves the determination of nutrient and contaminant concentrations in seafood for which data need to be collected. This article describes the process of building up a database containing previously published contaminant concentrations in seafood, and defining input distributions characterizing the variability. During the constitution of the database, several problems influencing the comparability of the data were encountered related to (1) sampling plans of the published data; (2) sample handling prior to analysis; (3) analytical methodologies; (4) the format of reporting results; and (5) missing data. Different solutions for these methodological problems have been developed. Contaminant concentrations ranges per gram fresh weight of 2.4–4390.0 ng for mercury, 0.1–5736.6 ng for the sum of indicator PCB, 0.002–115.000 pg TEQ for the sum of all PCBs, 0.002–34.400 pg TEQ for dioxins, and 0.006–126.000 pg TEQ for total of dioxin-like compounds were found. This work confirms that more guidelines are needed to standardize the analytical methodologies to be used and the format for result reporting in order to improve the comparability of data critical to conduct a human intake and risk-benefit assessment. 相似文献
990.