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161.
Donald G Newman Ben D Bell Phillip J Bishop Rhys Burns Amanda Haigh Rodney A Hitchmough 《New Zealand journal of zoology.》2013,40(2):121-130
Abstract A reappraisal of the conservation status of the New Zealand frog fauna is presented using the 2008 version of the New Zealand Threat Classification System. Of New Zealand's four extant endemic species, three are judged to be ‘Threatened’ (Leiopelma hamiltoni being ‘Nationally Critical’, and L. pakeka and L. archeyi being ‘Nationally Vulnerable’) and one ‘At Risk’ (L. hochstetteri ‘Declining’). Three Leiopelma species are listed as extinct—they are known from bone deposits in caves throughout the country until some time in the last 1000 years. Three introduced and naturalised Litoria species are abundant in New Zealand although two (L. aurea and L. raniformis) are threatened in their country of origin (Australia). An additional unidentified frog taxon from northern Great Barrier Island is listed as ‘Data Deficient’. 相似文献
162.
Barbara Cheney Paul M. Thompson Simon N. Ingram Philip S. Hammond Peter T. Stevick John W. Durban Ross M. Culloch Simon H. Elwen Laura Mandleberg Vincent M. Janik Nicola J. Quick Valentina ISLAS‐Villanueva Kevin P. Robinson Marina Costa Sonja M. Eisfeld Alice Walters Charlie Phillips Caroline R. Weir Peter G.H. Evans Pia Anderwald Robert J. Reid James B. Reid Ben Wilson 《Mammal Review》2013,43(1):71-88
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163.
Sofiene Larif Chaker Ben Salem Zohra Soua Houssem Hmouda Kamel Bouraoui 《Journal of biomolecular structure & dynamics》2013,31(10):1066-1076
Thiopurine S-methyltransferase (TPMT) is an important enzyme that metabolizes thiopurine drugs. This enzyme exhibits a large number of interindividual polymorphism. TPMT?23 polymorphism has been reported in a few cases in the world in co-dominance with TPMT?3A. The phenotype has been reported to affect enzyme activity in vivo and in vitro. Its underlying structural basis is not clarified yet. In our study, the wild type (WT) protein structure was analyzed and the amino acids bordering water channels in thiopurine sites were identified. Molecular dynamics of both the WT and TPMT?23 mutation was carried out. In addition, the effects of this mutation, especially on the thiopurine site which is closed with a pincer like mechanism, were investigated. We focused on explaining how a locally occurred A167G substitution propagated through hydrogen bonds alteration to induce structural modification which affects both thiopurine and S-adenosylmethionine receptors. Finally, a genetic prediction of mutation functional consequences has been conducted confirming altered activity. An animated Interactive 3D Complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:20 相似文献
164.
Ian Ilizaliturri-Flores José Correa-Basurto Claudia G. Benítez-Cardoza 《Journal of biomolecular structure & dynamics》2013,31(11):1707-1719
The anti-apoptotic B-cell lymphoma 2 (Bcl-2) protein interacts with several proteins that regulate the apoptotic properties of cells. In this research, we conduct several all-atom molecular dynamics (MD) simulations under high-temperature unfolding conditions, from 400 to 800?K, for 25?ns. These simulations were performed using a model of an engineered Bcl-2 human protein (Bcl-2-Δ22Σ3), which lacks 22 C-terminal residues of the transmembrane domain. The aim of this study is to gain insight into the structural behavior of Bcl-2-Δ22Σ3 by mapping the conformational movements involved in Bcl-2 stability and its biological function. To build a Bcl-2-Δ22Σ3 three-dimensional model, the protein core was built by homology modeling and the flexible loop domain (FLD, residues 33-91) by ab initio methods. Further, the entire protein model was refined by MD simulations. Afterwards, the production MD simulations showed that the FLD at 400 and 500?K has several conformations reaching into the protein core, whereas at 600?K some of the alpha-helices were lost. At 800?K, the Bcl-2 core is destabilized suggesting a possible mechanism for protein unfolding, where the alpha helices 1 and 6 were the most stable, and a reduction in the number of hydrogen bonds initially occurs. In conclusion, the structural changes and the internal protein interactions suggest that the core and the FLD are crucial components of Bcl-2 in its function of regulate ng access to the recognition sites of kinases and caspases. 相似文献
165.
Dorra Dridi Mossadok Ben‐Attia Mamane Sani Nassim Djebli François Ludovic Sauvage 《Chronobiology international》2013,30(4):533-547
Little is known about the chronopharmacokinetics of loratadine, a long‐acting tricyclic antihistamine H1 widely used in the treatment of allergic diseases. Hence, the pharmacokinetics of loratadine and its major metabolite, desloratadine, were investigated after a 20 mg/kg dose of loratadine had been orally administered to comparable groups of mice (n=33), synchronized for three weeks to 12 h light (rest span)/12 h dark (activity span). The drug was administered at three different circadian times (1, 9, and 17 h after light onset [HALO]). Multiple blood samples were collected over 48 h, and plasma concentrations of loratadine and desloratadine were determined by high performance liquid chromatography. There were no significant differences in Tmax of loratadine and desloratadine between treatment‐time different groups. However, the elimination half‐life (t1/2) of the parent compound and its metabolite was significantly longer (p<0.01) following administration at 9 HALO (t1/2 loratadine and desloratadine 5.62 and 4.08 h at 9 HALO vs. 4.29 and 2.6 h at 17 HALO vs. 3.26 and 3.27 at 1 HALO). There were relevant (p<0.05) differences in Cmax between the three treated groups for loratadine and desloratadine; 133.05±3.55 and 258.07±14.45 ng/mL at 9 HALO vs. 104.5±2.61 and 188.62±7.20 ng/mL at 1 HALO vs. 94.33±20 and 187.75±10.79 ng/mL at 17 HALO. Drug dosing at 17 HALO resulted in highest loratadine and desloratadine total apparent clearance values: 61.46 and 15.97 L/h/kg, respectively, whereas loratadine and desloratadine clearances (CL) were significantly slower (p<0.05) at the other administration times (loratadine and desloratadine CL was 57.3 and 14.22 L/h/kg at 1 HALO vs. 43.79 and 12.89 L/h/kg at 9 HALO, respectively). The area under the concentration‐time curve (AUC) of loratadine and desloratadine was significantly (p<0.05) greater following drug administration at 9 HALO (456.75 and 1550.57 (ng/mL) · h, respectively); it was lowest following treatment at 17 HALO (325.39 and 1252.53 (ng/mL) · h, respectively). These pharmacokinetic data indicate that the administration time of loratadine significantly affected its pharmacokinetics: the elimination of loratadine and its major metabolite desloratadine. 相似文献
166.
Hannah R. Windley Ian R. Wallis Jane L. DeGabriel Ben D. Moore Christopher N. Johnson William J. Foley 《Oecologia》2013,173(1):203-212
Estimating the nutritional value of a herbivore’s diet is difficult because it requires knowing what the animal eats, the relative quality of each component and how these components interact in relation to animal physiology. Current methods are cumbersome and rely on many assumptions that are hard to evaluate. We describe a new method for estimating relative diet quality directly from faeces that avoids the problems inherent in other methods. We combine this method with near infrared reflectance spectroscopy (NIRS) to analyse many samples and thus provide a technique with immense value in ecological studies. The method stems from the correlation between the concentrations of dietary and faecal nitrogen in herbivores eating a tannin-free diet, but a weaker relationship in browsers that ingest substantial amounts of tannins, which form complexes with proteins. These complexes reduce the availability of nitrogen and may increase faecal nitrogen concentrations. Using the tannin-binding compound, polyethylene glycol, we showed that tannin-bound nitrogen is a significant and variable part of faecal nitrogen in wild common brushtail possums (Trichosurus vulpecula). We developed a technique to measure faecal available nitrogen and found that it predicted the reproductive success of female brushtail possums in northern Australia. Faecal available nitrogen combined with NIRS provides a powerful tool for estimating the relative nutritional value of the diets of browsing herbivores in many ecological systems. It is a better indicator of diet quality than other commonly used single-nutrient measures such as faecal nitrogen and foliage analysis paired with observed feeding behaviour. 相似文献
167.
168.
M. L. Merroun N. Ben Omar E. Alonso J. M. Arias M. T. GonzÁlez-MuÑoz 《Geomicrobiology journal》2013,30(2):183-192
This paper deals with silver sorption to Myxococcus xanthus biomass. The dry biomass of this microorganism is shown to be a good sorbent for the recovery of silver present at low solution concentrations. Between initial silver concentrations of 2 and 0.05 mM, the percentage of accumulation ranges from 8.12% to 75% of the total silver present in the solution. Transmission electron microscopy study of M. xanthus wet biomass after silver accumulation shows the sorption within the extracellular polysaccharide, on the cell wall, and in the cytoplasm. The presence of silver deposits in the cytoplasm indicates that at least two mechanisms are involved in silver sorption by this bacterium biomass. First, silver was bound to the cell surface and extracellular polysaccharide, and second, a silver intracellular deposition process took place. The higher amount of silver deposits in the extracellular polysaccharide, present abundantly in M. xanthus cells, explains the capacity of this bacterium to bind silver efficiently. The results obtained indicate that the removal of silver by M. xanthus from the diluted solutions could be used in recycling this valuable metal. One interesting observation of this investigation is the crystalline form, possibly as chlorargyrite, in which the silver deposits are found in the M. xanthus cells. 相似文献
169.
Ibtissem Ben Amara Aida Karray Ahmed Hakim Yassine Ben Ali Afef Troudi Nejla Soudani Tahia Boudawara Khaled Mounir Zeghal Najiba Zeghal 《Biological trace element research》2013,156(1-3):230-242
Dimethoate (DM) is an organophosphate insecticide widely used in agriculture and industry and has toxic effects on non-target organisms especially mammalian. However, we still know little about DM-induced kidney injury and its alleviation by natural antioxidants. In the present study, selenium (Se), vitamin E, DM, Se+DM, vitamin E+DM, Se+vitamin E+DM were given to adult rats for 4 weeks. Plasma creatinine and uric acid, kidney MDA, PC, H2O2 and AOPP levels were higher, while Na+-K+-ATPase and LDH values were lower in the DM group than those of controls. A smear without ladder formation on agarose gel was shown in the DM group, indicating random DNA degradation and DM-induced genotoxicity. A decrease in kidney GSH, NPSH and plasma urea levels and an increase in GPx, SOD and catalase activities were observed in the DM group when compared to those of controls. Plasma cystatin C levels increased, indicating a decrease in glomerular filtration rate. When Se or vitamin E was added through diet, the biochemical parameters cited above were partially restored in Se+DM and vitamin E+DM than DM group. The joint effect of Se and vitamin E was more powerful against DM-induced oxidative stress and kidney dysfunction. The changes in biochemical parameters were substantiated by histological data. In conclusion, our results indicated a possible mechanism of DM-induced nephrotoxicity, where renal genotoxicity was noted, membrane-bound ATPases and plasma biomarkers were disturbed. Se and vitamin E ameliorated the toxic effects of this pesticide in renal tissue suggesting their role as potential antioxidants. 相似文献