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131.
Time-dependent yields of the most important products of water radiolysis , •OH, H•, H3O+, H2, OH− and H2O2 have been calculated for 60Co-photons, electrons, protons, helium- and carbon-ions incident onto water. G values have been evaluated for the interval from 1 ps to 1 μs after initial energy deposition as a function of time, as well
as after 1 ns and at the end of the chemical stage as a function of linear energy transfer (LET), covering an interval from
approximately 0.2 up to 750 keV/μm by means of different particle types. In this work, the modules of the biophysical Monte
Carlo track structure code PARTRAC dealing with the simulation of prechemical and chemical stages have been improved to extend
interaction data sets for heavier ions. Among other newly selected parameter values, the thermalisation distance between the
point of generation and hydration of subexcitation electrons has been adopted from recent data in the literature. As far as
data from the literature are available, good agreement has been found with the calculated time- and LET-dependent yields in
this work, supporting the selection of the revised parameter values. 相似文献
132.
Carina Nielsen Maximilian Casteel Andrea Didier Richard Dietrich Erwin Märtlbauer 《Mycotoxin Research》2009,25(2):77-84
Trichothecene cytotoxicity of type A (T-2 toxin and HT-2 toxin), type B (deoxynivalenol, DON, and nivalenol, NIV), and type
D (satratoxins G and H) compounds was determined comparatively by using eight permanent human cell lines (Hep-G2, A549, CaCo-2,
HEp-2, A204, U937, RPMI 8226, and Jurkat). Viability of cells was measured by a water-soluble tetrazolium (WST-1) reagent
cell proliferation assay assessing mitochondrial metabolic activity. Toxicity was expressed as the toxin concentration inhibiting
50% of cell viability (IC50). Depending on the chemotype of the tested trichothecenes, relative cytotoxic activity differed by a factor of 100–1,000,
and the corresponding IC50 values were in the range from 2.2 nmol/l (satratoxin H on Jurkat and U937 cells) to 4,900 nmol/l (deoxynivalenol on HEp-2
cells). In contrast, the specific toxicity of each individual mycotoxin towards different cell lines was within remarkable
close limits, and between-cell line differences were much smaller than previously reported. For the cell lines tested, IC50 values were 4.4–10.8 nmol/l for T-2 toxin, 7.5–55.8 mol/l for HT-2 toxin, 600–4,900 nmol/l for DON, 300–2,600 nmol/l for
NIV, and 2.2–18.3 nmol/l for satratoxins G/H. In addition, for the first time, the toxic activity of trichothecenes on primary
cell culture of human endothelial cells (HUVEC) was tested. The susceptibility of this cell line was comparable to the other
cell lines tested, with IC50 values ranging from 16.5 nmol/l (T-2 toxin) to 4,500 nmol/l (DON). The results suggest that the current focus of cytotoxicological
studies on trichothecenes on lymphoid cell lines may lead to an underestimate of their potential on other target cell systems. 相似文献
133.
Doreen Siegel Maximilian Schuff Franz Oswald Ying Cao Walter Knöchel 《Mechanisms of development》2009,126(11-12):974-989
The maintenance of pluripotency in mammalian embryonic stem cells depends upon the expression of regulatory genes like Oct3/4 and Sox2. While homologues of these genes are also characterized in non-mammalian vertebrates, like birds, amphibians and fish, existence and function of developmental pluripotency associated genes (Dppa) in lower vertebrates have not yet been reported. Here we describe a Dppa2/4-like gene, XDppa2/4, in Xenopus. The protein contains a SAP domain and a conserved C-terminal region. Overexpression of XDppa2/4, murine Dppa2 or Dppa4 produces similar phenotypes (defects in blastopore closure), while injection of XDppa2/4 morpholino generates a loss of blastopore closure and neural fold formation. Embryos die up to tailbud stage. mDppa2 (but not mDppa4) rescues blastopore closure and neurulation defects caused by XDppaMO, but does not prevent subsequent death of embryos. Although XDppa2/4 exhibits a Dppa-like expression pattern and is indispensable for embryogenesis, analyses of various marker genes make its role as a pluripotency factor rather unlikely. Both the gain and loss of function effects until the end of neurulation are caused by the conserved C-terminal region but not by the SAP domain. The SAP domain is required for association of XDppa2/4 to chromatin and for embryonic survival at later stages of development suggesting epigenetic programming events. 相似文献
134.
Maximilian Kern Zasie Schäfer Alexander Buchberger 《Biochemical and biophysical research communications》2009,380(2):303-38678
The chaperone-related p97 protein plays a central role in various cellular processes involving the ubiquitin-proteasome system. The diverse functions of p97 are controlled by a large number of cofactors that recruit specific substrates or influence their ubiquitylation state. Many cofactors bind through a UBX or PUB domain, two major p97 binding modules. However, the recently identified UBXD1 cofactor possesses both domains. To elucidate the molecular basis underlying the interaction between UBXD1 and p97, we analyzed the contribution of both domains to p97 binding biochemically and in living cells. The PUB domain mediated robust binding to the carboxy-terminus of p97, while the UBX domain did not contribute to p97 binding. Importantly, we identified an additional p97 binding site in UBXD1 that competed with the p47 cofactor for binding to the N domain of p97. This novel, bipartite binding mode suggests that UBXD1 could be an efficient regulator of p97 cofactor interactions. 相似文献
135.
Dong-Chuan Guo Christina L. Papke Van Tran-Fadulu Nili Avidan Dong H. Kim Marcia C. Willing Reed E. Pyeritz Ronald L. Dalman Ali J. Marian Eric A. Boerwinkle Lorraine Q. Frazier Joseph S. Coselli Anthony L. Estrera Sudha Veeraraghavan David A. Wheeler Robert K. Yu Steven E. Scherer L. Maximilian Buja 《American journal of human genetics》2009,84(5):617-627
The vascular smooth muscle cell (SMC)-specific isoform of α-actin (ACTA2) is a major component of the contractile apparatus in SMCs located throughout the arterial system. Heterozygous ACTA2 mutations cause familial thoracic aortic aneurysms and dissections (TAAD), but only half of mutation carriers have aortic disease. Linkage analysis and association studies of individuals in 20 families with ACTA2 mutations indicate that mutation carriers can have a diversity of vascular diseases, including premature onset of coronary artery disease (CAD) and premature ischemic strokes (including Moyamoya disease [MMD]), as well as previously defined TAAD. Sequencing of DNA from patients with nonfamilial TAAD and from premature-onset CAD patients independently identified ACTA2 mutations in these patients and premature onset strokes in family members with ACTA2 mutations. Vascular pathology and analysis of explanted SMCs and myofibroblasts from patients harboring ACTA2 suggested that increased proliferation of SMCs contributed to occlusive diseases. These results indicate that heterozygous ACTA2 mutations predispose patients to a variety of diffuse and diverse vascular diseases, including TAAD, premature CAD, ischemic strokes, and MMD. These data demonstrate that diffuse vascular diseases resulting from either occluded or enlarged arteries can be caused by mutations in a single gene and have direct implications for clinical management and research on familial vascular diseases. 相似文献
136.
Audrey L. Mayer Leena Vihermaa Noora Nieminen Annukka Luomi Maximilian Posch 《Ecological Indicators》2009,9(5):992-1000
Novel systems combining bioindicators, models, and remote sensing are possible cost-effective methods to monitor regional-scale pollution. Epiphytic macrolichen communities have been widely used as air pollution bioindicators, however these communities are also affected by microclimate conditions as influenced by forest structure. We used the Finnish epiphytic macrolichen survey method SFS5670 to collect data in 27 spruce and birch dominated forests in southern Finland and northwestern Russia. The method measures the abundance and physiological damage of Hypogymnia physodes and Bryoria spp., and the frequency of 13 epiphytic macrolichen species of known sensitivity which can be used to calculate the widely used Index of Atmospheric Purity (IAP). The location of the sites represents an east–west gradient of air pollution conditions of SO2, SO42?, NO2, NH3 + NH4+, and HNO3 + NO3?. We also recorded living and dead forest structure characteristics at these sites, which we initially chose to be as similar as possible on either side of the border. Abundance and damage of H. physodes were correlated with forest structure but not with air pollution, indicating that these macrolichen variables may not be reliable bioindicators at low air pollution concentrations. However, the Index of Atmospheric Purity, calculated from observed presence/absence data of multiple epiphytic macrolichen species, was strongly correlated with sulfur and nitrogen pollutant concentrations. These results suggest that the IAP as calculated using data from the Finnish epiphytic macrolichen survey method may be a useful air pollution indicator in combination with modeled data, even in relatively clean regions. 相似文献
137.
Wallis D Arcos-Burgos M Jain M Castellanos FX Palacio JD Pineda D Lopera F Stanescu H Pineda D Berg K Palacio LG Bailey-Wilson JE Muenke M 《Attention deficit and hyperactivity disorders》2009,1(1):19-24
The neural nicotinic acetylcholine receptor α4 subunit (CHRNA4), at 20q13.2-q13.3, is an important candidate gene for conferring susceptibility to attention deficit/hyperactivity disorder (ADHD). Several studies have already looked for association/linkage between ADHD and CHRNA4 in different populations. We used the Pedigree Disequilibrium Test to search for evidence of association between ADHD and six SNP marker loci in families from the isolated Paisa population. We found that the T allele of SNP rs6090384 exhibits a deficit of transmission in unaffected individuals (OR = 5.43, IC 1.54-19.13) (global P value = 0.014). We also found significant association and linkage to extended haplotypes rs2273502-rs6090384 (combination of variants C-T, respectively) (P = 0.02) and rs6090384-rs6090387 (P = 0.04) (combination of variants T-G, respectively). SNP rs6090384, variant T, has also been reported to be associated with inattention in a previous study. This makes ours the ninth study to examine the association of CHRNA4 with ADHD and the seventh one to find evidence for association in a population with a different ethnicity. 相似文献
138.
Katiuska Molina-Luna Ana Pekanovic Sebastian R?hrich Benjamin Hertler Maximilian Schubring-Giese Mengia-Seraina Rioult-Pedotti Andreas R. Luft 《PloS one》2009,4(9)
Preliminary evidence indicates that dopamine given by mouth facilitates the learning of motor skills and improves the recovery of movement after stroke. The mechanism of these phenomena is unknown. Here, we describe a mechanism by demonstrating in rat that dopaminergic terminals and receptors in primary motor cortex (M1) enable motor skill learning and enhance M1 synaptic plasticity. Elimination of dopaminergic terminals in M1 specifically impaired motor skill acquisition, which was restored upon DA substitution. Execution of a previously acquired skill was unaffected. Reversible blockade of M1 D1 and D2 receptors temporarily impaired skill acquisition but not execution, and reduced long-term potentiation (LTP) within M1, a form of synaptic plasticity critically involved in skill learning. These findings identify a behavioral and functional role of dopaminergic signaling in M1. DA in M1 optimizes the learning of a novel motor skill. 相似文献
139.
140.