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821.
The interaction of static magnetic fields (SMFs) with living organisms is a rapidly growing field of investigation. The magnetic fields (MFs) effect observed with radical pair recombination is one of the well-known mechanisms by which MFs interact with biological systems. SMF influenced cellular antioxidant defense mechanisms by affecting antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT). However, there were insufficient reports about the effects of SMF on macro and trace elements in serum, and the results were contradictory until now. In the current study, 12 rats were divided into two groups, namely as control and exposure group (128 mT and 1 h/day during five consecutive days). The macro and trace element concentrations in serum were examined. No significant difference was observed in the sodium (Na), potassium (K), calcium (Ca), phosphorus (P), and selenium (Se) levels in rat compared to control. By contrast, exposure to SMF showed an increase in the zinc (Zn) level and a decrease in iron (Fe) concentration. Under our experimental conditions, SMF exposure cannot affect the plasma levels of macroelements, while it can disrupt Zn and Fe concentrations in rat.  相似文献   
822.
Two novel series of 2-substituted estradiol derivatives have been synthesized and evaluated for uterotrophic and antiimplantation activities. Among the compounds tested in the rat, 2-acetylestradiol 17 beta-acetate (1), 2-(3'-dimethylamino-1'-propionyl)estradiol 3,17 beta-diacetate (7), 2-(3'-diethylamino-1'-propionyl)estradiol 3,17 beta-diacetate (8), 2-(3'-piperidino-1'-propionyl)estradiol 3,17 beta-diacetate (9), 1'-(2-estradiol 3,17 beta-diacetate-3'-diethylaminopropionyl thiosemicarbazone (12), and 1'-(2-estradiol 3,17 beta-diacetate)-3'-morpholinopropionyl thiosemicarbazone (14) displayed estrogenic activity. At dosages of 4 microliters/rat/day, none of the tested compounds elicited antiimplantation activity. All compounds shared a similar characteristic: nuclear substitution at the C-2 position of the steroid nucleus, a property previously thought to be markedly inhibitory for estrogenic activity.  相似文献   
823.
Combination therapy is a novel cancer therapy approach that combines two or more chemotherapy drugs. This treatment modality enhances the efficacy of chemotherapy by targeting key pathways in an additive or synergistic manner. Therefore, we investigated the efficacy of combination therapy by widely used chemotherapy drug doxorubicin (DOX) and oleanolic acid (OA) to induction of apoptosis for pancreatic cancer (PC) therapy. The effects of DOX, OA, and their combination (DOX-OA) were investigated on proliferation and viability of PC cell line (PANC-1) by MTT assay. Moreover, migration and invasion of the cancer cells were evaluated by trans-well migration assay and wound healing assay. Flow cytometry and DAPI (4′,6-diamidino-2-phenylindole) staining were employed to investigate apoptosis quantification and qualification of the treated cancer cells. Finally, mRNA expression of apoptosis-related genes was assessed by quantitative real-time polymerase chain reaction. Our results demonstrated that the proliferation and metastasis potential of PC cells significantly decreased after treatment by DOX, OA, and DOX-OA. Moreover, we observed an increase in apoptosis percentage in the treated cancer cells. The apoptosis-related gene expression was modified to increase the apoptosis rate in all of the treatment groups. However, the anticancer potency of DOX-OA combination was significantly more than that of DOX and OA treatments alone. Our study suggested that DOX-OA combination exerts more profound anticancer effects against PC cell lines than DOX or OA monotherapy. This approach may increase the efficiency of chemotherapy and reduce unintended side effects by lowering the prescribed dose of DOX.  相似文献   
824.
Small populations of plant species can be susceptible to demographic Allee effects mainly due to pollen limitation. Although sympatry with a common, co-flowering species may somewhat alleviate the problem of pollinator visitation (pollination quantity), the interspecific pollen transfer, IPT, (pollination quality) may remain a barrier to reproduction in small populations such as new introductions. However, if the two species are crosscompatible, our hypothesis is that neutral hybridization can help the small founding population overcome the Allee effect by improving the quality of pollination. We tested this hypothesis by using a novel modelling approach based on the theory of kinetic reactions wherein pollinators act as enzymes to catalyse the reaction between the two substrates: pollen and unselfed ovule. Using a single locus, two-allele genetic model, we developed a generic model that allows for hybridization between the invading and the native genotypes. Analysing the stability properties of the trivial equilibria in hybridization model as compared with the single genotype invasion model, we found that hybridization can either remove or reduce the Allee effect by making an otherwise stable trivial equilibrium unstable. Our study suggests that hybridization can be neutral but still be the key driver of a successful invasion by mediating pollen limitation. Conservation programmes should therefore account for this cryptic role that hybridization could play in plant invasions.  相似文献   
825.
Motivated by the recent nanophotonic community, in this work, we address the behavior of quantized charge-density fluctuations of doped and gated semiconductor armchair-type graphene nanoribbons within the tight-binding model and the Green’s function technique. In particular, we study the behavior of frequency-dependent susceptibility, when the system is exposed to photons or electrons. Injecting electrons by doping or ejecting ones by gating lead to different treatments in response function. Doping offers new collective modes due to added states between the valence and conduction bands (provided by the density of states) corresponding to intraband transitions, while gating distributes intraband modes. The results show that both ribbon width and doping concentrations affect the intraband transitions in electro-optical devices. Another remarkable point is the strong sensitivity of intraband plasmons to the direction of incoming photons or electrons. We found that the susceptibility of doped nanoribbons vanishes at perpendicular angles due to the distribution of intraband modes.  相似文献   
826.
The Protein Journal - Enteropeptidase is a duodenum serine protease that triggers the activation of pancreatic enzymes by remarkably specific cleavages after lysine residues of peptidyl substrate...  相似文献   
827.
In late December 2019 in Wuhan, China, several patients with viral pneumonia were identified as 2019 novel coronavirus (2019-nCoV). So far, there are no specific treatments for patients with coronavirus disease-19 (COVID-19), and the treatments available today are based on previous experience with similar viruses such as severe acute respiratory syndrome-related coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and Influenza virus. In this article, we have tried to reach a therapeutic window of drugs available to patients with COVID-19. Cathepsin L is required for entry of the 2019-nCoV virus into the cell as target teicoplanin inhibits virus replication. Angiotensin-converting-enzyme 2 (ACE2) in soluble form as a recombinant protein can prevent the spread of coronavirus by restricting binding and entry. In patients with COVID-19, hydroxychloroquine decreases the inflammatory response and cytokine storm, but overdose causes toxicity and mortality. Neuraminidase inhibitors such as oseltamivir, peramivir, and zanamivir are invalid for 2019-nCoV and are not recommended for treatment but protease inhibitors such as lopinavir/ritonavir (LPV/r) inhibit the progression of MERS-CoV disease and can be useful for patients of COVID-19 and, in combination with Arbidol, has a direct antiviral effect on early replication of SARS-CoV. Ribavirin reduces hemoglobin concentrations in respiratory patients, and remdesivir improves respiratory symptoms. Use of ribavirin in combination with LPV/r in patients with SARS-CoV reduces acute respiratory distress syndrome and mortality, which has a significant protective effect with the addition of corticosteroids. Favipiravir increases clinical recovery and reduces respiratory problems and has a stronger antiviral effect than LPV/r. currently, appropriate treatment for patients with COVID-19 is an ACE2 inhibitor and a clinical problem reducing agent such as favipiravir in addition to hydroxychloroquine and corticosteroids.  相似文献   
828.
Abstract A murine monoclonal antibody, designated MA-2G9, directed against outer surface protein A (OspA) of the Lyme disease spirochete, Borrelia burgdorferi , has been produced. Antibody MA-2G9, IgG1 subclass, was purified by affinity chromatography on protein G Sepharose column and used for purification of OspA antigen from Borrelia burgdorferi cell lysate. Epitope specificity was studied by Western immunoblotting, using several strains of B. burgdorferi and non-Lyme disease bacteria such as Treponema pallidum and B. hermsii . The MA-2G9 monoclonal antibody reacted specifically with recombinant OspA aas well as with native OspA in sonicated B. burgdorferi strains. No reaction was observed with T. pallidum, Escherichia coli, Staphylococcus aureus and B. hermsii lysates. The MA-2G9 antibody also recognized the denatured form of OspA indicating that it is directed against sequential epitope and not conformational epitope.  相似文献   
829.
The susceptibility of fourth instar larvae of Culiseta longiareolata (Macq.) to two standard strains of biocontrol bacteria was investigated under laboratory conditions. Larvae were found to be more susceptible to Bacillus sphaericus (Bs-IPS88) than to Bacillus thuringiensis H14 (Bti-IPS82) at 25 ± 1°C at concentrations ranging from 0.003 to 0.004 ppm at 2 and 3 days post-treatment. Statistical regression analysis revealed a significant mortality–concentration relationship for the two bacteria. Larval mortality increased significantly as temperature increased from 20 ± 1°C to 28 ± 1°C.  相似文献   
830.
OBJECTIVE: To establish whether the relation between size at birth and non-insulin dependent diabetes is mediated through impaired beta cell function or insulin resistance. DESIGN: Cohort study. SETTING: Uppsala, Sweden. SUBJECTS: 1333 men whose birth records were traced from a cohort of 2322 men born during 1920-4 and resident in Uppsala in 1970. MAIN OUTCOME MEASURES: Intravenous glucose tolerance test at age 50 years and non-insulin dependent diabetes at age 60 years. RESULTS: There was a weak inverse correlation (r=-0.07, P=0.03) between ponderal index at birth and 60 minute insulin concentrations in the intravenous glucose tolerance test at age 50 years. This association was stronger (r=-0.19, P=0.001) in the highest third of the distribution of body mass index than in the other two thirds (P=0.01 for the interaction between ponderal index and the body mass index). Prevalence of diabetes at age 60 years was 8% in men whose birth weight was less than 3250 g compared with 5% in men with birth weight 3250 g or more (P=0.08; 95% confidence interval for difference -0.3% to 6.8%). There was a stronger association between diabetes and ponderal index: prevalence of diabetes was 12% in the lowest fifth of ponderal index compared with 4% in the other four fifths (P=0.001; 3.0% to 12.6%). CONCLUSION: These results confirm that reduced fetal growth is associated with increased risk of diabetes and suggest a specific association with thinness at birth. This relation seems to be mediated through insulin resistance rather than through impaired beta cell function and to depend on an interaction with obesity in adult life.  相似文献   
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