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911.
Lee JS Agrawal S von Turkovich M Taatjes DJ Walz DA Jena BP 《Journal of cellular and molecular medicine》2012,16(4):945-949
The regulation of platelet volume significantly affects its function. Because water is the major molecule in cells and its active transport via water channels called aquaporins (AQPs) have been implicated in cellular and organelle volume regulation, the presence of water channels in platelets and their potential role in platelet volume regulation was investigated. G-protein-mediated AQP regulation in secretory vesicle swelling has previously been reported in neurons and in pancreatic acinar cells. Mercuric chloride has been demonstrated to inhibit most AQPs except AQP6, which is stimulated by the compound. Exposure of platelets to HgCl(2)-induced swelling in a dose-dependent manner, suggesting the presence of AQP6 in platelets. Immunoblot analysis of platelet protein confirmed the presence of AQP6, and also of G(αo), G(αi-1) and G(αi-3) proteins. Results from this study demonstrate for the first time that in platelets AQP6 is involved in cell volume regulation via a G-protein-mediated pathway. 相似文献
912.
El-Sabaawi RW Kohler TJ Zandoná E Travis J Marshall MC Thomas SA Reznick DN Walsh M Gilliam JF Pringle C Flecker AS 《PloS one》2012,7(3):e32713
The elemental composition of animals, or their organismal stoichiometry, is thought to constrain their contribution to nutrient recycling, their interactions with other animals, and their demographic rates. Factors that affect organismal stoichiometry are generally poorly understood, but likely reflect elemental investments in morphological features and life history traits, acting in concert with the environmental availability of elements. We assessed the relative contribution of organismal traits and environmental variability to the stoichiometry of an insectivorous Neotropical stream fish, Rivulus hartii. We characterized the influence of body size, life history phenotype, stage of maturity, and environmental variability on organismal stoichiometry in 6 streams that differ in a broad suite of environmental variables. The elemental composition of R. hartii was variable, and overlapped with the wide range of elemental composition documented across freshwater fish taxa. Average %P composition was ~3.2%(±0.6), average %N~10.7%(±0.9), and average %C~41.7%(±3.1). Streams were the strongest predictor of organismal stoichiometry, and explained up to 18% of the overall variance. This effect appeared to be largely explained by variability in quality of basal resources such as epilithon N:P and benthic organic matter C:N, along with variability in invertebrate standing stocks, an important food source for R. hartii. Organismal traits were weak predictors of organismal stoichiometry in this species, explaining when combined up to 7% of the overall variance in stoichiometry. Body size was significantly and positively correlated with %P, and negatively with N:P, and C:P, and life history phenotype was significantly correlated with %C, %P, C:P and C:N. Our study suggests that spatial variability in elemental availability is more strongly correlated with organismal stoichiometry than organismal traits, and suggests that the stoichiometry of carnivores may not be completely buffered from environmental variability. We discuss the relevance of these findings to ecological stoichiometry theory. 相似文献
913.
Kate S. Collison Soad M. Saleh Razan H. Bakheet Rana K. Al‐Rabiah Angela L. Inglis Nadine J. Makhoul Zakia M. Maqbool Marya Zia Zaidi Mohammed A. Al‐Johi Futwan A. Al‐Mohanna 《Obesity (Silver Spring, Md.)》2009,17(11):2003-2013
Nonalcoholic fatty liver disease (NAFLD) is associated with obesity and insulin resistance. It is also a predisposing factor for type 2 diabetes. Dietary factors are believed to contribute to all three diseases. NAFLD is characterized by increased intrahepatic fat and mitochondrial dysfunction, and its etiology may be attributed to excessive fructose intake. Consumption of high fructose corn syrup‐55 (HFCS‐55) stands at up to 15% of the average total daily energy intake in the United States, and is linked to weight gain and obesity. The aim of this study was to establish whether HFCS‐55 could contribute to the pathogenesis of NAFLD, by examining the effects of HFCS‐55 on hepatocyte lipogenesis, insulin signaling, and cellular function, in vitro and in vivo. Exposure of hepatocytes to HFCS‐55 caused a significant increase in hepatocellular triglyceride (TG) and lipogenic proteins. Basal production of reactive oxygen metabolite (ROM) was increased, together with a decreased capacity to respond to an oxidative challenge. HFCS‐55 induced a downregulation of the insulin signaling pathway, as indicated by attenuated ser473phosphorylation of AKT1. The c‐Jun amino‐terminal kinase (JNK), which is intimately linked to insulin resistance, was also activated; and this was accompanied by an increase in endoplasmic reticulum (ER) stress and intracellular free calcium perturbation. Hepatocytes exposed to HFCS‐55 exhibited mitochondrial dysfunction and released cytochrome C (CytC) into the cytosol. Hepatic steatosis and mitochondrial disruption was induced in vivo by a diet enriched with 20% HFCS 55; accompanied by hypoadiponectinemia and elevated fasting serum insulin and retinol‐binding protein‐4 (RBP4) levels. Taken together our findings indicate a potential mechanism by which HFCS‐55 may contribute to the pathogenesis of NAFLD. 相似文献
914.
915.
Shivani Ponnala Kaipa P. Rao Jaideep R. Chaudhury Jaleel Ahmed B. Rama Rao Sanjith Kanjilal Qurratulain Hasan Undurti N. Das 《Prostaglandins, leukotrienes, and essential fatty acids》2009,80(1):43-50
Phenytoin sodium/diphenyl hydantoin (DPH) is used by a major segment of epileptics and neuro surgery patients with head injury to prevent seizures. DPH is a known mutagen, carcinogen, and teratogen. Essential fatty acids (EFAs) are critical for various tissues and were reported to act as anti-mutagenic agents. In the present study we assessed the effect of five EFAs on DPH-induced genetic damage both in vitro and in vivo. DPH induced significant genetic damage. Of all the EFAs (linoleic acid, α-linolenic acid, gamma-linolenic acid, arachidonic acid, dihomo-gamma-linolenic acid, and eicosapentaenoic acid) studied, all except eicosapentaenoic acid showed significant decrease in DPH induced genetic damage as assessed by micronucleus (MN) test. However, gamma-linolenic acid (GLA) was found to be the most effective in reducing the number of MN containing lymphocytes both in vitro and in vivo to control values. EFAs when tested alone produced insignificant increase in the amount of genetic damage but when tested in combination with DPH the number of micronuclei containing lymphocytes was reduced; but the DNA ladder pattern, an indication of DNA damage, was increased. This apparently paradoxical action of EFAs, especially of GLA, suggests that, in all probability, fatty acids induce apoptosis of cells that harbor significant DNA damage. Based on these results we suggest that GLA functions as a unique endogenous molecule that protects cells from accumulating genetic damage. 相似文献
916.
Dhaval P. Patel Chitral Mallikarjuna Setty Gaurav N. Mistry Santnu L. Patel Tarun J. Patel Pritesh C. Mistry Amar K. Rana Pritesh K. Patel Rishabh S. Mishra 《AAPS PharmSciTech》2009,10(2):437-442
Transdermal films of the furosemide were developed employing ethyl cellulose and hydroxypropyl methylcellulose as film formers.
The effect of binary mixture of polymers and penetration enhancers on physicochemical parameters including thickness, moisture
content, moisture uptake, drug content, drug–polymer interaction, and in vitro permeation was evaluated. In vitro permeation study was conducted using human cadaver skin as penetration barrier in modified Keshary–Chein diffusion cell.
In vitro skin permeation study showed that binary mixture, ethyl cellulose (EC)/hydroxypropyl methylcellulose (HPMC), at 8.5:1.5 ratio
provided highest flux and also penetration enhancers further enhanced the permeation of drug, while propylene glycol showing
higher enhancing effect compared to dimethyl sulfoxide and isopropyl myristate. Different kinetic models, used to interpret
the release kinetics and mechanism, indicated that release from all formulations followed apparent zero-order kinetics and
non-Fickian diffusion transport except formulation without HPMC which followed Fickian diffusion transport. Stability studies
conducted as per International Conference on Harmonization guidelines did not show any degradation of drug. Based on the above
observations, it can be reasonably concluded that blend of EC–HPMC polymers and propylene glycol are better suited for the
development of transdermal delivery system of furosemide. 相似文献
917.
Kenneth D. Rose Rajendra S. Rana Kishor Kumar Lachham Singh 《Journal of human evolution》2009,56(4):366-404
The oldest euprimates known from India come from the Early Eocene Cambay Formation at Vastan Mine in Gujarat. An Ypresian (early Cuisian) age of ∼53 Ma (based on foraminifera) indicates that these primates were roughly contemporary with, or perhaps predated, the India-Asia collision. Here we present new euprimate fossils from Vastan Mine, including teeth, jaws, and referred postcrania of the adapoids Marcgodinotius indicus and Asiadapis cambayensis. They are placed in the new subfamily Asiadapinae (family Notharctidae), which is most similar to primitive European Cercamoniinae such as Donrussellia and Protoadapis. Asiadapines were small primates in the size range of extant smaller bushbabies. Despite their generally very plesiomorphic morphology, asiadapines also share a few derived dental traits with sivaladapids, suggesting a possible relationship to these endemic Asian adapoids. In addition to the adapoids, a new species of the omomyid Vastanomys is described. Euprimate postcrania described include humeri, radii, femora, calcanei, and tali, most of which show typical notharctid features and are probably attributable to asiadapines. Anatomical features of the limb elements indicate that they represent active arboreal quadrupedal primates. At least one calcaneus is proximally shorter and distally longer than the others, resembling eosimiids in this regard, a relationship that, if confirmed, would also suggest an Asian or southeast Asian faunal connection. Isolated teeth from Vastan Mine recently attributed to a new eosimiid, Anthrasimias gujaratensis, appear to provide that confirmation. However, their attribution to Eosimiidae is equivocal. They are similar to teeth here tentatively referred to Marcgodinotius, hence A. gujaratensis may be a junior synonym of M. indicus. Corroboration of eosimiids at Vastan requires more compelling evidence. Although definitive conclusions are premature, available evidence suggests that the Vastan adapoids, at least, were derived from western European stock that reached India near the Paleocene-Eocene boundary. 相似文献
918.
Chakraborty T Pandey N Chatterjee A Ghosh B Rana B Chatterjee M 《Mutation research》2006,609(2):117-128
Carcinogen-induced DNA base modification and subsequent DNA lesions are the critical events for the expression of premalignant phenotype of the cell. We have therefore investigated the chemopreventive efficacy of a vanadium salt against diethylnitrosamine (DEN)-induced early DNA and chromosomal damages in rat liver. Hepatocarcinogenesis was induced in male Sprague-Dawley rats with a single, necrogenic, intraperitoneal injection of DEN (200mg/kg body weight). 8-Hydroxy-2'-deoxyguanosines (8-OHdGs), strand-breaks and DNA-protein crosslinks (DPCs) were measured by HPLC, comet assay and spectrofluorimetry, respectively. There was a significant and steady elevation of modified bases 8-OHdGs along with substantial increments of the extent of single-strand-breaks (SSBs), DPCs and chromosomal aberrations (CAs) following DEN exposure. Supplementation of vanadium as ammonium metavanadate (NH(4)VO(3), +V oxidation state) at a dose of 0.5ppm in terms of the salt weight throughout the experiment abated the formations of 8-OHdGs (P<0.0001; 79.54%), tailed DNA (P<0.05; 31.55%) and length:width of DNA mass (P<0.02; 61.25%) in preneoplastic rat liver. Vanadium treatment also inhibited DPCs (P<0.0001; 58.47%) and CAs (P<0.001; 45.17%) studied at various time points. The results indicate that the anticlastogenic potential of vanadium in vivo might be due to the observed reductions in liver-specific 8-OHdGs, SSBs and/or DPCs by this trace metal. We conclude that, vanadium plays a significant role in limiting DEN-induced genotoxicity and clastogenicity during the early stages of hepatocarcinogenesis in rats. 相似文献
919.
Incubation of placental brush border membrane (BBM) along with sonicated vesicles of exogenous lipids (egg yolk PC) in the presence of phospholipid-transfer protein (PL-TP) showed a decrease in the alkaline phosphatase activity due to the change in the membrane micro-environment, such as fluidity. Effect of substrate concentration was tested by Lineweaver-Burk plot, which showed decreased V(max) and K(M). The effect of temperature was probed by the Arrhenius plot, which showed no change in transition temperature, but a decline in the energy of activation both below and above the transition temperature. The protein-catalyzed transfer of phospholipid from the donor unilamellar vesicles resulted in a substantial increase in the BBM phospholipid and a net decrease in cholesterol/phospholipid molar ratio. The change in membrane fluidity was assessed by translational as well as rotational diffusion of membrane extrinsic fluorescent probes, pyrene and diphenyl-hexatriene. An increased lateral mobility was recorded by the increased pyrene excimer formation. A decrease in fluorescent polarization of diphenyl-hexatriene was observed, which led to the decrease in fluorescence anisotropy and order parameter, and therefore, an increase in membrane fluidity (rotational diffusion). Mean anisotropy parameter was also decreased in the presence of PL-TP. Thus, the placental BBM alkaline phosphatase activity showed a distinct lipid dependence which may have important physiological consequences. 相似文献
920.
Shivani M Chidrawar Naeem Khan Y L Tracey Chan Laxman Nayak Paul AH Moss 《Immunity & ageing : I & A》2006,3(1):10-8