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91.
Körner A Kratzsch J Gausche R Blüher S Kapellen T Pulzer F Behrens M Kiess W 《Archives of physiology and biochemistry》2008,114(4):237-243
The clinical relevance of the term "metabolic syndrome", the definition criteria, and predictive power are being disputed. Inclusion of sleep-disordered breathing and sleep apnoea into a definition of metabolic syndrome is also controversial once children and/or adolescents are affected. Nevertheless, along with the increasing prevalence of childhood obesity, the prevalence of the metabolic syndrome in obese children is reported at 30%, irrespective of the definition applied. Moreover, childhood obesity is associated with sleep-disordered breathing. Adipocytokines, cytokines secreted from adipose tissue, are thought to play a major role in the pathophysiology of metabolic syndrome. Leptin was initially suggested as a promising "anti-obesity" hormone. New concepts indicate that in humans leptin and its soluble receptor may be more important in states of energy deficiency rather than a predictor of the metabolic syndrome. Adiponectin, on the other hand, is not only related to obesity and insulin resistance, but appears to be the strongest predictor for metabolic syndrome, even in children. In newborns and infants, both adipocytokines occur in high concentrations, even though this cannot completely explain the increased risk for ensuing metabolic disease later in life. Finally, low-grade systemic inflammation may underlie the clustering of metabolic risk factors. Overall factors from the adipose tissue may constitute not only markers but also mediators of metabolic sequelae of obesity. 相似文献
92.
Middle Devonian (Givetian) pillow basalt and inter-pillow breccia from the Rheinisches Schiefergebirge in Germany were found to contain putative biogenic filaments that indicate that life once proliferated within these volcanic rocks. Mineralized filaments are found in carbonate amygdules (vesicles filled by carbonate cement) in the volcanic rock, where they started to form on the internal surface of the once water-filled vesicles. Biogenicity of the filaments is indicated by (1) their size and shape resembling modern microorganisms including a constant diameter along the length of curved filaments, (2) their independence of crystal faces or cleavage planes, (3) branching patterns reminiscent of modern microorganisms, and (4) their spatial clustering and preferential occurrence close to the margin of pillows and in the inter-pillow breccias. A time lag between the deposition of pillow basalt and the activity of endoliths is revealed by the sequence of carbonate cements filling the amygdules. The putative filamentous microorganisms thrived after the formation of early fibrous rim cement, but before later equant calcite spar filled most of the remaining porosity. Microbial clay authigenesis analogous to the encrustation of prokaryotes in modern iron-rich environments led to the preservation of filaments. The filaments predominantly consist of the clay minerals chamosite and illite. Having dwelled in water-filled vesicles, the Devonian basalt-hosted filaments apparently represent cryptoendoliths. This finding suggests that a previously unrecognized niche for life exists within volcanic rock. 相似文献
93.
Rita Triebskorn Stefan Adam Anja Behrens Stefanie Beier Jürgen Böhmer Thomas Braunbeck 《人类与生态风险评估》2003,9(1):171-194
The study summarizes the objectives of the VALIMAR project and gives selected examples of biomarker responses that allow causal relationships to be established between exposure and biological effects at different levels of biological organization. In this project, active and passive biomonitoring experiments with brown trout (Salmo trutta f. fario) and stone loach (Barbatula barbatula) were performed in two small streams in southern Germany between 1995 and 1999 in parallel with investigations on contaminant mixtures in the laboratory in order to evaluate the suitability of biomarkers representing different levels of biological organization for the assessment of pollution in small streams. In addition to biomarker studies, the morphology of the test streams was characterized and limnological and chemical parameters were monitored. Early life stage tests and ecological studies of brown trout and stone loach population demography, of the fish assemblages, and the macro- and meiozoobenthos communities in the two test streams were included in the project. Several causality criteria were addressed by means of combined (1) laboratory and field studies, (2) chemical, biological, and statistical investigations, and (3) in vivo and in vitro studies that allowed establishment of cause-effect relationships at different biological levels. The comparison of results obtained at these levels allowed identification of mechanisms responsible for the respective effects (coherence of association, biological plausibility). Finally, individual responses (biomarkers, bioindicators) could be extrapolated to higher biological levels (population, community) thus addressing the criteria of ‘time order’ and ‘coherence of association’. 相似文献
94.
Andreas Schaate Miriam Schulte Adelheid Godt Peter Behrens 《Inorganica chimica acta》2009,362(10):3600-9325
The rigid, π-conjugated dicarboxylic acid 1,4-bis-[2-(4-carboxyphenyl)ethynyl]-2,5-dihexylbenzene {HO2C[PEP(hexyl)2EP]CO2H} has been used to synthesise the new crystalline coordination polymers {Zn(O2C[PEP(hexyl)2EP]CO2)(DMF)2} (1) and {Zn(O2C[PEP(hexyl)2EP]CO2)(DEF)2} (2) in N,N-dimethylformamide (DMF) and N,N-diethylformamide (DEF), respectively, under mild conditions. Single-crystal X-ray crystallography revealed that 1 and 2 are isostructural and consist of uncharged zigzag coordination chains in which [Zn(formamide)2]2+ fragments are bridged by (O2C[PEP(hexyl)2EP]CO2)2− ligands. The zigzag chains possess different intra-chain Zn?Zn?Zn angles due to the different volumes of the coordinating formamide molecules and subtle differences in the hydrophobic inter-chain interactions. Upon heating 1 and 2 to 200 °C, removal of the coordinating formamide molecules occurs, yielding the formamide-free compounds 1-DMF and 2-DEF of composition {Zn(O2C[PEP(hexyl)2EP]CO2)}. According to powder X-ray diffraction and FT-IR spectroscopy studies, these materials are not crystalline but still possess partial ordering of intact, yet modified coordination chains in a structural arrangement which appears to be related to the respective parent compounds. Compounds 1, 2, 1-DMF and 2-DEF exhibit blue photoluminescence. The emission maxima of 1-DMF and 2-DEF are red-shifted by ca. 25 nm with respect to λmax of 1 and 2, respectively. 相似文献
95.
Gabriele Helms Bernd-Arno Behrens Martin Stolorz Patrick Wefstaedt Ingo Nolte 《Biomedical engineering online》2009,8(1):36-9
Background
Among other causes the long-term result of hip prostheses in dogs is determined by aseptic loosening. A prevention of prosthesis complications can be achieved by an optimization of the tribological system which finally results in improved implant duration. In this context a computerized model for the calculation of hip joint loadings during different motions would be of benefit. In a first step in the development of such an inverse dynamic multi-body simulation (MBS-) model we here present the setup of a canine hind limb model applicable for the calculation of ground reaction forces. 相似文献96.
Shang-Te Danny Hsu Caroline Behrens Lisa D. Cabrita Christopher M. Dobson 《Biomolecular NMR assignments》2009,3(1):67-72
We present here the backbone and side-chain NMR assignments of YFP Venus, a 238-residue protein that emits yellow fluorescence
in its native state. Venus is a variant of the green fluorescent protein (GFP), which has improved chromophore maturation
and brightness, and the photochemistry and photophysics of which are insensitive to experimental conditions, such as the pH
value and buffer content, making it a favourable biomarker. 相似文献
97.
98.
99.
Tanneberger K Pfister AS Brauburger K Schneikert J Hadjihannas MV Kriz V Schulte G Bryja V Behrens J 《The EMBO journal》2011,30(8):1433-1443
Phosphorylation of the Wnt receptor low-density lipoprotein receptor-related protein 6 (LRP6) by glycogen synthase kinase 3β (GSK3β) and casein kinase 1γ (CK1γ) is a key step in Wnt/β-catenin signalling, which requires Wnt-induced formation of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)). Here, we show that adenomatous polyposis coli membrane recruitment 1 (Amer1) (also called WTX), a membrane associated PtdIns(4,5)P(2)-binding protein, is essential for the activation of Wnt signalling at the LRP6 receptor level. Knockdown of Amer1 reduces Wnt-induced LRP6 phosphorylation, Axin translocation to the plasma membrane and formation of LRP6 signalosomes. Overexpression of Amer1 promotes LRP6 phosphorylation, which requires interaction of Amer1 with PtdIns(4,5)P(2). Amer1 translocates to the plasma membrane in a PtdIns(4,5)P(2)-dependent manner after Wnt treatment and is required for LRP6 phosphorylation stimulated by application of PtdIns(4,5)P(2). Amer1 binds CK1γ, recruits Axin and GSK3β to the plasma membrane and promotes complex formation between Axin and LRP6. Fusion of Amer1 to the cytoplasmic domain of LRP6 induces LRP6 phosphorylation and stimulates robust Wnt/β-catenin signalling. We propose a mechanism for Wnt receptor activation by which generation of PtdIns(4,5)P(2) leads to recruitment of Amer1 to the plasma membrane, which acts as a scaffold protein to stimulate phosphorylation of LRP6. 相似文献
100.
Krempski J Karyampudi L Behrens MD Erskine CL Hartmann L Dong H Goode EL Kalli KR Knutson KL 《Journal of immunology (Baltimore, Md. : 1950)》2011,186(12):6905-6913
Within the ovarian cancer microenvironment, there are several mechanisms that suppress the actions of antitumor immune effectors. Delineating the complex immune microenvironment is an important goal toward developing effective immune-based therapies. A dominant pathway of immune suppression in ovarian cancer involves tumor-associated and dendritic cell (DC)-associated B7-H1. The interaction of B7-H1 with PD-1 on tumor-infiltrating T cells is a widely cited theory of immune suppression involving B7-H1 in ovarian cancer. Recent studies suggest that the B7-H1 ligand, programmed death receptor-1 (PD-1), is also expressed on myeloid cells, complicating interpretations of how B7-H1 regulates DC function in the tumor. In this study, we found that ovarian cancer-infiltrating DCs progressively expressed increased levels of PD-1 over time in addition to B7-H1. These dual-positive PD-1(+) B7-H1(+) DCs have a classical DC phenotype (i.e., CD11c(+)CD11b(+)CD8(-)), but are immature, suppressive, and respond poorly to danger signals. Accumulation of PD-1(+)B7-H1(+) DCs in the tumor was associated with suppression of T cell activity and decreased infiltrating T cells in advancing tumors. T cell suppressor function of these DCs appeared to be mediated by T cell-associated PD-1. In contrast, ligation of PD-1 expressed on the tumor-associated DCs suppressed NF-κB activation, release of immune regulatory cytokines, and upregulation of costimulatory molecules. PD-1 blockade in mice bearing ovarian cancer substantially reduced tumor burden and increased effector Ag-specific T cell responses. Our results reveal a novel role of tumor infiltrating PD-1(+)B7-H1(+) DCs in mediating immune suppression in ovarian cancer. 相似文献