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61.
Petra van der Lelij Krystyna H. Chrzanowska Barbara C. Godthelp Martin A. Rooimans Anneke B. Oostra Markus Stumm Ma?gorzata Z. Zdzienicka Hans Joenje Johan P. de Winter 《American journal of human genetics》2010,86(2):262-1182
The iron-sulfur-containing DNA helicases XPD, FANCJ, DDX11, and RTEL represent a small subclass of superfamily 2 helicases. XPD and FANCJ have been connected to the genetic instability syndromes xeroderma pigmentosum and Fanconi anemia. Here, we report a human individual with biallelic mutations in DDX11. Defective DDX11 is associated with a unique cellular phenotype in which features of Fanconi anemia (drug-induced chromosomal breakage) and Roberts syndrome (sister chromatid cohesion defects) coexist. The DDX11-deficient patient represents another cohesinopathy, besides Cornelia de Lange syndrome and Roberts syndrome, and shows that DDX11 functions at the interface between DNA repair and sister chromatid cohesion. 相似文献
62.
Ilka Haase Simone M?rtl Peter K?hler Adelbert Bacher Markus Fischer 《European journal of biochemistry》2003,270(5):1025-1032
Heterologous expression of the putative open reading frame MJ0303 of Methanococcus jannaschii provided a recombinant protein catalysing the formation of the riboflavin precursor, 6,7-dimethyl-8-ribityllumazine, by condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione and 3,4-dihydroxy-2-butanone 4-phosphate. Steady state kinetic analysis at 37 degrees C and pH 7.0 indicated a catalytic rate of 11 nmol.mg-1.min-1; Km values for 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione and 3,4-dihydroxybutanone 4-phosphate were 12.5 and 52 micro m, respectively. The enzyme sediments at an apparent velocity of about 12 S. Sedimentation equilibrium analysis indicated a molecular mass around 1 MDa but was hampered by nonideal solute behaviour. Negative-stained electron micrographs showed predominantly spherical particles with a diameter of about 150 A. The data suggest that the enzyme from M. jannaschii can form capsids with icosahedral 532 symmetry consisting of 60 subunits. 相似文献
63.
J?rg Müller Valentin H. Klaus Till Kleinebecker Daniel Prati Norbert H?lzel Markus Fischer 《PloS one》2012,7(12)
While bryophytes greatly contribute to plant diversity of semi-natural grasslands, little is known about the relationships between land-use intensity, productivity, and bryophyte diversity in these habitats. We recorded vascular plant and bryophyte vegetation in 85 agricultural used grasslands in two regions in northern and central Germany and gathered information on land-use intensity. To assess grassland productivity, we harvested aboveground vascular plant biomass and analyzed nutrient concentrations of N, P, K, Ca and Mg. Further we calculated mean Ellenberg indicator values of vascular plant vegetation. We tested for effects of land-use intensity and productivity on total bryophyte species richness and on the species richness of acrocarpous (small & erect) and pleurocarpous (creeping, including liverworts) growth forms separately. Bryophyte species were found in almost all studied grasslands, but species richness differed considerably between study regions in northern Germany (2.8 species per 16 m2) and central Germany (6.4 species per 16 m2) due environmental differences as well as land-use history. Increased fertilizer application, coinciding with high mowing frequency, reduced bryophyte species richness significantly. Accordingly, productivity estimates such as plant biomass and nitrogen concentration were strongly negatively related to bryophyte species richness, although productivity decreased only pleurocarpous species. Ellenberg indicator values for nutrients proved to be useful indicators of species richness and productivity. In conclusion, bryophyte composition was strongly dependent on productivity, with smaller bryophytes that were likely negatively affected by greater competition for light. Intensive land-use, however, can also indirectly decrease bryophyte species richness by promoting grassland productivity. Thus, increasing productivity is likely to cause a loss of bryophyte species and a decrease in species diversity. 相似文献
64.
Felipe Leal Valentim Simon van Mourik David Posé Min C. Kim Markus Schmid Roeland C. H. J. van Ham Marco Busscher Gabino F. Sanchez-Perez Jaap Molenaar Gerco C. Angenent Richard G. H. Immink Aalt D. J. van Dijk 《PloS one》2015,10(2)
Various environmental signals integrate into a network of floral regulatory genes leading to the final decision on when to flower. Although a wealth of qualitative knowledge is available on how flowering time genes regulate each other, only a few studies incorporated this knowledge into predictive models. Such models are invaluable as they enable to investigate how various types of inputs are combined to give a quantitative readout. To investigate the effect of gene expression disturbances on flowering time, we developed a dynamic model for the regulation of flowering time in Arabidopsis thaliana. Model parameters were estimated based on expression time-courses for relevant genes, and a consistent set of flowering times for plants of various genetic backgrounds. Validation was performed by predicting changes in expression level in mutant backgrounds and comparing these predictions with independent expression data, and by comparison of predicted and experimental flowering times for several double mutants. Remarkably, the model predicts that a disturbance in a particular gene has not necessarily the largest impact on directly connected genes. For example, the model predicts that SUPPRESSOR OF OVEREXPRESSION OF CONSTANS (SOC1) mutation has a larger impact on APETALA1 (AP1), which is not directly regulated by SOC1, compared to its effect on LEAFY (LFY) which is under direct control of SOC1. This was confirmed by expression data. Another model prediction involves the importance of cooperativity in the regulation of APETALA1 (AP1) by LFY, a prediction supported by experimental evidence. Concluding, our model for flowering time gene regulation enables to address how different quantitative inputs are combined into one quantitative output, flowering time. 相似文献
65.
Minimal sample requirement for highly multiplexed protein quantification in cell lines and tissues by PCT‐SWATH mass spectrometry 下载免费PDF全文
Shiying Shao Tiannan Guo Chiek Ching Koh Silke Gillessen Markus Joerger Wolfram Jochum Ruedi Aebersold 《Proteomics》2015,15(21):3711-3721
The amount of sample available for clinical and biological proteomic research is often limited and thus significantly restricts clinical and translational research. Recently, we have integrated pressure cycling technology (PCT) assisted sample preparation and SWATH‐MS to perform reproducible proteomic quantification of biopsy‐level tissue samples. Here, we further evaluated the minimal sample requirement of the PCT‐SWATH method using various types of samples, including cultured cells (HeLa, K562, and U251, 500 000 to 50 000 cells) and tissue samples (mouse liver, heart, brain, and human kidney, 3–0.2 mg). The data show that as few as 50 000 human cells and 0.2–0.5 mg of wet mouse and human tissues produced peptide samples sufficient for multiple SWATH‐MS analyses at optimal sample load applied to the system. Generally, the reproducibility of the method increased with decreasing tissue sample amounts. The SWATH maps acquired from peptides derived from samples of varying sizes were essentially identical based on the number, type, and quantity of identified peptides. In conclusion, we determined the minimal sample required for optimal PCT‐SWATH analyses, and found smaller sample size achieved higher quantitative accuracy. 相似文献
66.
Abhishek Cukkemane Deepak Nand Sabine Gradmann Markus Weingarth U. Benjamin Kaupp Marc Baldus 《Biomolecular NMR assignments》2012,6(2):225-229
Channels regulated by cyclic nucleotides are key signalling proteins in several biological pathways. The regulatory aspect is conferred by a C-terminal cyclic nucleotide-binding domain (CNBD). We report resonance assignments of the CNBD of a bacterial mlCNG channel obtained using 2D and 3D solid-state NMR under Magic-angle Spinning conditions. A secondary chemical shift analysis of the 141 residue protein suggests a three-dimensional fold seen in earlier X-ray and solution-state NMR work and points to spectroscopic polymorphism for a selected set of resonances. 相似文献
67.
68.
Reverse gyrase is the only topoisomerase that can introduce positive supercoils into DNA in an ATP-dependent process. It has a modular structure and harnesses a helicase-like domain to support a topoisomerase activity, thereby creating the unique function of positive DNA supercoiling. The isolated topoisomerase domain can relax negatively supercoiled DNA, an activity that is suppressed in reverse gyrase. The isolated helicase-like domain is a nucleotide-dependent switch that is attenuated by the topoisomerase domain. Inter-domain communication thus appears central for the functional cooperation of the two domains. The latch, an insertion into the helicase-like domain, has been suggested as an important element in coordinating their activities. Here, we have dissected the influence of the latch on nucleotide and DNA binding to the helicase-like domain, and on DNA supercoiling by reverse gyrase. We find that the latch is required for positive DNA supercoiling. It is crucial for the cooperativity of DNA and nucleotide binding to the helicase-like domain. The latch contributes to DNA binding, and affects the preference of reverse gyrase for ssDNA. Thus, the latch coordinates the individual domain activities by modulating the helicase-like domain, and by communicating changes in the nucleotide state to the topoisomerase domain. 相似文献
69.
Markus Helfer Herwig Koppensteiner Martha Schneider Stephanie Rebensburg Sara Forcisi Constanze Müller Philippe Schmitt-Kopplin Michael Schindler Ruth Brack-Werner 《PloS one》2014,9(1)
Global HIV-1 treatment would benefit greatly from safe herbal medicines with scientifically validated novel anti-HIV-1 activities. The root extract from the medicinal plant Pelargonium sidoides (PS) is licensed in Germany as the herbal medicine EPs®7630, with numerous clinical trials supporting its safety in humans. Here we provide evidence from multiple cell culture experiments that PS extract displays potent anti-HIV-1 activity. We show that PS extract protects peripheral blood mononuclear cells and macrophages from infection with various X4 and R5 tropic HIV-1 strains, including clinical isolates. Functional studies revealed that the extract from PS has a novel mode-of-action. It interferes directly with viral infectivity and blocks the attachment of HIV-1 particles to target cells, protecting them from virus entry. Analysis of the chemical footprint of anti-HIV activity indicates that HIV-1 inhibition is mediated by multiple polyphenolic compounds with low cytotoxicity and can be separated from other extract components with higher cytotoxicity. Based on our data and its excellent safety profile, we propose that PS extract represents a lead candidate for the development of a scientifically validated herbal medicine for anti-HIV-1 therapy with a mode-of-action different from and complementary to current single-molecule drugs. 相似文献
70.
Markus M. Heimesaat Ildiko R. Dunay Silvia Schulze André Fischer Ursula Grundmann Marie Alutis Anja A. Kühl Andrea Tamas Gabor Toth Miklos P. Dunay Ulf B. G?bel Dora Reglodi Stefan Bereswill 《PloS one》2014,9(9)