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991.
Richter C Messerschmidt S Holeiter G Tepperink J Osswald S Zappe A Branschädel M Boschert V Mann DA Scheurich P Krippner-Heidenreich A 《Molecular and cellular biology》2012,32(13):2515-2529
The family of tumor necrosis factor receptors (TNFRs) and their ligands form a regulatory signaling network that controls immune responses. Various members of this receptor family respond differently to the soluble and membrane-bound forms of their respective ligands. However, the determining factors and underlying molecular mechanisms of this diversity are not yet understood. Using an established system of chimeric TNFRs and novel ligand variants mimicking the bioactivity of membrane-bound TNF (mTNF), we demonstrate that the membrane-proximal extracellular stalk regions of TNFR1 and TNFR2 are crucial in controlling responsiveness to soluble TNF (sTNF). We show that the stalk region of TNFR2, in contrast to the corresponding part of TNFR1, efficiently inhibits both the receptor's enrichment/clustering in particular cell membrane regions and ligand-independent homotypic receptor preassembly, thereby preventing sTNF-induced, but not mTNF-induced, signaling. Thus, the stalk regions of the two TNFRs not only have implications for additional TNFR family members, but also provide potential targets for therapeutic intervention. 相似文献
992.
St Amour CV Sansó M Bösken CA Lee KM Larochelle S Zhang C Shokat KM Geyer M Fisher RP 《Molecular and cellular biology》2012,32(13):2372-2383
993.
Heiko G. R?del Robyn Hudson Lena Rammler Nina S?nger Lisa Schwarz Peter Machnik 《Journal of Ethology》2012,30(2):263-270
Individual consistency over time in behavioral responses to challenging situations is usually regarded as an indication of
the existence of animal personality types. Although such consistency has been found in a variety of species, information about
long-term stability is scanty, in particular across different life history stages, for example reproductive and non-reproductive
periods, which have the potential to affect substantially the behavioral responses of animals. In our study of adult female
laboratory mice, we explored the stability of behavioral responses across a 43-day period by successively testing the animals
on an elevated plus maze. We tested two groups, one group that had offspring during the first two tests but not during the
last test, and another group that only had offspring during the last test. We found clear evidence of individual consistency
over time by means of positive significant correlations across the different tests: animals that spent more time in the closed
arms and those that entered the open arms more often during the first test also tended to do so during the second test—when
still in the same reproductive state, and also during the third test—when in a different reproductive state. In addition,
females of the two groups did not differ overall in their responses, although we found a significant increase in the frequency
and duration of presumed anxiety-related behavior during the course of the experiment, contradicting the notion that habituation
effects should attenuate the challenge of the test situation. In conclusion, our study strongly suggests the existence of
stable personality types in female laboratory mice, even across different reproductive stages. 相似文献
994.
Woudstra C Skarin H Anniballi F Fenicia L Bano L Drigo I Koene M Bäyon-Auboyer MH Buffereau JP De Medici D Fach P 《Applied and environmental microbiology》2012,78(9):3120-3127
Clostridium botulinum types C and D, as well as their mosaic variants C-D and D-C, are associated with avian and mammalian botulism. This study reports on the development of low-density macroarrays based on the GeneDisc cycler platform (Pall-GeneDisc Technologies) applied to the simultaneous detection of the C. botulinum subtypes C, C-D, D, and D-C. The limit of detection of the PCR assays was 38 fg of total DNA, corresponding to 15 genome copies. Artificially contaminated samples of cecum showed a limit of detection below 50 spores/g. The tests were performed with a large variety of bacterial strains, including C. botulinum types C (n = 12), C-D (n = 29), D (n = 5), and D-C (n = 10), other botulinum neurotoxin (BoNT)-producing Clostridium strains (n = 20), non-BoNT-producing clostridia (n = 20), and other bacterial species (n = 23), and showed a high specificity. These PCR assays were compared to previously published real-time PCRs for the detection of C. botulinum in 292 samples collected from cases of botulism events in four European regions. The majority of the samples originated from wild birds (n = 108), poultry (n = 60), and bovines (n = 56). Among the 292 samples, 144 were positive for either the bont/C-D or the bont/D-C gene by using the GeneDisc arrays. The reliability of the results tallied to 97.94%. Interestingly, only BoNT mosaics, types C-D and D-C, were found in naturally contaminated samples whatever their animal origin and their geographical location. Further investigations should now be performed in order to check that mosaic types dominate in Europe and that acquisition of mosaic types helps in survival or adaptation to particular niche. 相似文献
995.
Rosa Gómez M. Isabel Arce J. Javier Sánchez M. del Mar Sánchez-Montoya 《Hydrobiologia》2012,679(1):43-59
Mediterranean climates predispose aquatic systems to both flood and drought periods, therefore, stream sediments may be exposed
to desiccation periods. Changes in oxygen concentrations and sediment water content influence the biotic processes implicated
in nitrogen dynamics. The objectives of this study were to identify (1) the changes of inorganic nitrogen in stream sediments
during the transition from wet to dry conditions, and (2) the underlying processes in N dynamics and its regulation. Extractable
sediment NO3
−-N and NH4
+-N, organic matter and extractable organic carbon content were assessed during natural desiccation in microcosms with sediments
from an intermittent Mediterranean stream. In agreement with our initial hypothesis, our results showed how the NO3
−-N content of the sediment was enhanced during the first 10 days of sediment drying, whereas NH4
+-N was lost by 14 days post-drying. During the first 10 days, sediment desiccation seemed to stimulate the net N-mineralization
and net nitrification from sediments. Afterwards, the extractable NO3
−-N concentration sharply dropped, which may be attributed to lower ammonium-oxidation rates as ammonium and organic matter
are depleted, and to an increase in NO3
−-N consumption by microbial populations. Denitrification was inhibited, with a significant decrease as % water-filled pore
space lowered. We hypothesize that the sediment inorganic N content enhanced during sediment desiccation could be released
as part of the N pulse observed after sediment rewetting. However, the stream N availability after rewetting dried sediments
would differ depending on desiccation period duration. 相似文献
996.
Steven D. Brown Sagar M. Utturkar Dawn M. Klingeman Courtney M. Johnson Stanton L. Martin Miriam L. Land Tse-Yuan S. Lu Christopher W. Schadt Mitchel J. Doktycz Dale A. Pelletier 《Journal of bacteriology》2012,194(21):5991-5993
To aid in the investigation of the Populus deltoides microbiome, we generated draft genome sequences for 21 Pseudomonas strains and 19 other diverse bacteria isolated from Populus deltoides roots. Genome sequences for isolates similar to Acidovorax, Bradyrhizobium, Brevibacillus, Caulobacter, Chryseobacterium, Flavobacterium, Herbaspirillum, Novosphingobium, Pantoea, Phyllobacterium, Polaromonas, Rhizobium, Sphingobium, and Variovorax were generated. 相似文献
997.
Brown SD Palumbo AV Panikov N Ariyawansa T Klingeman DM Johnson CM Land ML Utturkar SM Epstein SS 《Journal of bacteriology》2012,194(12):3279-3280
Microbacterium laevaniformans strain OR221 was isolated from subsurface sediments obtained from the Field Research Center (FRC) in Oak Ridge, TN. It was characterized as a bacterium tolerant to heavy metals, such as uranium, nickel, cobalt, and cadmium, as well as nitrate and low pH. We present its draft genome sequence. 相似文献
998.
999.
Lauffer S Mäbert K Czupalla C Pursche T Hoflack B Rödel G Krause-Buchholz U 《The Journal of biological chemistry》2012,287(21):17447-17458
Numerous transport processes occur between the two mitochondrial (mt) membranes due to the diverse functions and metabolic processes of the mt organelle. The metabolite and ion transport through the mt outer membrane (OM) is widely assumed to be mediated by the porin pore, whereas in the mt inner membrane (IM) specific carriers are responsible for transport processes. Here, we provide evidence by means of Blue Native (BN)-PAGE analysis, co-immunoprecipitation, and tandem affinity purification that the two mt OM proteins Om14p and Om45p associate with the porin pore. Porin molecules seem to assemble independently to build the core unit. A subpopulation of these core units interacts with Om14p and Om45p. With preparative tandem affinity purification followed by MS analysis, we could identify interaction partners of this OM complex, which are mainly localized within the mt IM and function as carriers for diverse molecules. We propose a model for the role of the two OM proteins in addressing the porin pore to bind to specific channels in the mt IM to facilitate transport of metabolites. 相似文献
1000.
YB Kim ME Balasis K Doi N Berndt C Duboulay CC Hu W Guida HG Wang SM Sebti JR Del Valle 《Bioorganic & medicinal chemistry letters》2012,22(18):5961-5965
Mcl-1, an anti-apoptotic member of the Bcl-2 protein family, is overexpressed in a broad range of human cancers and plays a critical role in conferring resistance to chemotherapy. In the course of screening a natural product-like library of sesquiterpenoid analogs, we identified substituted hexahydronaphthalenes that showed activity against the Mcl-1/BimBH3 interaction in vitro. Here, we describe the synthesis of a small library of analogs and their biological evaluation. The most potent inhibitor in the series (19) exhibits an IC(50) of 8.3μM by ELISA and disrupts the interaction between endogenously expressed Mcl-1 and Bim in cultured MDA-MB-468 breast cancer cells. 相似文献