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971.
972.
Farook Thameem V Saroja Voruganti John Blangero Anthony G Comuzzie Hanna E Abboud 《Journal of biomedical science》2015,22(1)
Background
The estimated glomerular filtration rate (eGFR) is a well-known measure of kidney function and is commonly used for the diagnosis and management of patients with chronic kidney disease. The inter-individual variation in eGFR has significant genetic component. However, the identification of underlying genetic susceptibility variants has been challenging. In an attempt to identify and characterize susceptibility genetic variant(s) we previously identified the strongest evidence for linkage of eGFR occurring on chromosome 9q21 in the Mexican American participants of San Antonio Family Heart Study (SAFHS). The objective of the present study was to examine whether the common genetic variants in Neurotrophic Tyrosine Receptor Kinase 2 (NTRK2), a positional candidate gene on 9q21, contribute to variation in eGFR.Results
Twelve tagging single nucleotide polymorphisms (SNPs) across the NTRK2 gene region were selected (r2 ≥ 0.80, minor allele frequency of ≥ 0.05) from the Hapmap database. SNPs were genotyped by TaqMan assay in the 848 Mexican American subjects participated in the SAFHS. Association analysis between the genotypes and eGFR (estimated by the Modification of Diet in Renal Disease equation) were performed by measured genotype approach as implemented in the program SOLAR. Of the 12 common genetic variants examined, the rs1036915 (located in 3′UTR) and rs1187274 (located in intron-14), present in perfect linkage disequilibrium, exhibited an association (P = 0.017) with eGFR after accounting for the effects of age, sex, diabetes, diabetes duration, systolic blood pressure and blood pressure medication. The carriers of minor allele of rs1036915 (G; 38%) had increased eGFR (104 ± 25 ml/min/1.73 m2) in comparison to the carriers of major allele A (98 ± 25 ml/min/1.73 m2).Conclusion
Together, our results suggest for the first time that the genetic variants in NTRK2 may regulate eGFR. 相似文献973.
974.
Mark C. Capece Guy L. Kornberg Alexey Petrov Joseph D. Puglisi 《RNA (New York, N.Y.)》2015,21(2):296-305
A high-throughput assay for real-time measurement of translation rates in cell-free protein synthesis (SNAP assay) is described. The SNAP assay enables quantitative, real-time measurement of overall translation rates in vitro via the synthesis of O6-alkylguanine DNA O6-alkyltransferase (SNAP). SNAP production is continuously detected by fluorescence produced by the reaction of SNAP with a range of quenched fluorogenic substrates. The capabilities of the assay are exemplified by measurements of the activities of Escherichia coli MRE600 ribosomes and fluorescently labeled E. coli mutant ribosomes in the PURExpress translation system and by determination of the 50% inhibitory concentrations (IC50) of three common macrolide antibiotics. 相似文献
975.
Bottom‐up processes in a declining yellow‐footed rock‐wallaby (Petrogale xanthopus celeris) population 下载免费PDF全文
Populations of large herbivores are generally considered to be food limited, escaping the regulatory effects of predation through their large body size, migratory behaviour and/or the occurrence of alternate prey species. In the Australian arid and semi‐arid zones, the availability of forage biomass is considered to be the primary driver of fluctuations in kangaroo abundance. However, little is known about the population dynamics of the smaller sympatric macropods. We examined the demographic traits of a large colony of yellow‐footed rock‐wallabies (Petrogale xanthopus celeris), following a 2‐year period of above average rainfall. The population was located within a conservation reserve that was subject to a predator control program around its perimeter and on neighbouring properties. The low predator abundance provided an opportunity to gauge the strength of bottom‐up population processes. During the two years of the study, the population declined in size by 53%, resulting from both the virtual absence of juvenile recruitment and the loss of adult wallabies. Although reproductive output was high, low pouch young and juvenile survival rates resulted in few individuals progressing into the adult population. With minimal recruitment, the rate of population decline (r = 0.77) matched the observed adult survival rate (Φ = 0.76). Despite average rainfall conditions during the study, survival rates across all age‐classes were equivalent to those reported for other rock‐wallaby populations during periods of scarcity. The reduced survival rates were attributed to low levels of forage resources, particularly around the wallabies' refuge sites, suggesting the bottom‐up regulation of the colony at high densities. The data suggest that the colony was at temporarily high abundance, following a rainfall driven pulse of recruitment. Conservation management actions for this species should focus on increasing juvenile survival rates within declining populations, through the control of feral goats (Capra hircus), rabbits (Oryctolagus cuniculus) and red foxes (Vulpes vulpes). 相似文献
976.
Callum R. Lawson Yngvild Vindenes Liam Bailey Martijn van de Pol 《Ecology letters》2015,18(7):724-736
Species' responses to environmental changes such as global warming are affected not only by trends in mean conditions, but also by natural and human‐induced environmental fluctuations. Methods are needed to predict how such environmental variation affects ecological and evolutionary processes, in order to design effective strategies to conserve biodiversity under global change. Here, we review recent theoretical and empirical studies to assess: (1) how populations respond to changes in environmental variance, and (2) how environmental variance affects population responses to changes in mean conditions. Contrary to frequent claims, empirical studies show that increases in environmental variance can increase as well as decrease long‐term population growth rates. Moreover, environmental variance can alter and even reverse the effects of changes in the mean environment, such that even if environmental variance remains constant, omitting it from population models compromises their ability to predict species' responses to changes in mean conditions. Drawing on theory relating these effects of environmental variance to the curvatures of population growth responses to the environment, we outline how species' traits such as phylogenetic history and body mass could be used to predict their responses to global change under future environmental variability. 相似文献
977.
Sheila L. MacRae Quanwei Zhang Christophe Lemetre Inge Seim Robert B. Calder Jan Hoeijmakers Yousin Suh Vadim N. Gladyshev Andrei Seluanov Vera Gorbunova Jan Vijg Zhengdong D. Zhang 《Aging cell》2015,14(2):288-291
Genome maintenance (GM) is an essential defense system against aging and cancer, as both are characterized by increased genome instability. Here, we compared the copy number variation and mutation rate of 518 GM‐associated genes in the naked mole rat (NMR), mouse, and human genomes. GM genes appeared to be strongly conserved, with copy number variation in only four genes. Interestingly, we found NMR to have a higher copy number of CEBPG, a regulator of DNA repair, and TINF2, a protector of telomere integrity. NMR, as well as human, was also found to have a lower rate of germline nucleotide substitution than the mouse. Together, the data suggest that the long‐lived NMR, as well as human, has more robust GM than mouse and identifies new targets for the analysis of the exceptional longevity of the NMR. 相似文献
978.
Leukocytes, as an indispensable arm of the immune system, need to be recruited from the flowing blood and transferred to the sites of infection. Their extravasation is feasible due to their ability to tether and roll over the activated endothelium, which is much dependent on the association of their selectin molecules with ligands on the activated endothelial cells. In view of the importance of this interaction for the physiological immune functions as well as for autoimmune diseases, specifying the affinity of selectins to their ligands at the single molecule level appears a challenging task to gain insight into the mechanisms that control leukocyte–endothelial avidity. To this end we functionalized substrates with P‐selectin and cantilever probes with its major ligand, the P‐selectin glycoprotein ligand‐1, and used atomic force microscopy to measure their unbinding force. Two different chemical protocols were used for the tethering of the molecules on the substrates, one based on a homobifunctional poly(ethylene glycol) linker and the other on the use of antibody‐specific binding. The unbinding forces measured with the two methods were 312 ± 149 and 230 ± 57 pN, respectively. Measurements on activated endothelials, declaratory of single molecule interactions, gave comparable results. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
979.
Johan De Vogel-van den Bosch Sjoerd A.A. van den Berg Silvia BijlandPeter J. Voshol Louis M. Havekes Hans A. RomijnJoris Hoeks Denis van Beurden Matthijs K.C. HesselinkPatrick Schrauwen Ko Willems van Dijk 《The Journal of nutritional biochemistry》2011,22(4):366-371
Excess dietary long-chain fatty acid (LCFA) intake results in ectopic lipid accumulation and insulin resistance. Since medium-chain fatty acids (MCFA) are preferentially oxidized over LCFA, we hypothesized that diets rich in MCFA result in a lower ectopic lipid accumulation and insulin resistance compared to diets rich in LCFA. Feeding mice high-fat (HF) (45% kcal fat) diets for 8 weeks rich in triacylglycerols composed of MCFA (HFMCT) or LCFA (HFLCT) revealed a lower body weight gain in the HFMCT-fed mice. Indirect calorimetry revealed higher fat oxidation on HFMCT compared to HFLCT (0.011.0±0.0007 vs. 0.0096±0.0015 kcal/g body weight per hour, P<.05). In line with this, neutral lipid immunohistochemistry revealed significantly lower lipid storage in skeletal muscle (0.05±0.08 vs. 0.30±0.23 area%, P <.05) and in liver (0.9±0.4 vs. 6.4±0.8 area%, P<.05) after HFMCT vs. HFLCT, while ectopic fat storage in low fat (LF) was very low. Hyperinsulinemic euglycemic clamps revealed that the HFMCT and HFLCT resulted in severe whole body insulin resistance (glucose infusion rate: 53.1±6.8, 50.8±15.3 vs. 124.6±25.4 μmol min−1 kg−1, P<.001 in HFMCT, HFLCT and LF-fed mice, respectively). However, under hyperinsulinemic conditions, HFMCT revealed a lower endogenous glucose output (22.6±8.0 vs. 34.7±8.5 μmol min−1 kg−1, P<.05) and a lower peripheral glucose disappearance (75.7±7.8 vs. 93.4±12.4 μmol min−1 kg−1, P<.03) compared to HFLCT-fed mice. In conclusion, both HF diets induced whole body insulin resistance compared to LF. However, the HFMCT gained less weight, had less ectopic lipid accumulation, while peripheral insulin resistance was more pronounced compared to HFLCT. This suggests that HF-diets rich in medium- versus long-chain triacylglycerols induce insulin resistance via distinct mechanisms. 相似文献
980.
H.-R. Pourian R. Talaei-Hassanloui A.A. Kosari A. Ashouri 《Biocontrol Science and Technology》2011,21(1):15-21
The generalist predator Orius albidipennis Reut. (Hem., Anthocoridae) and entomopathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin (Ascomycota: Clavicipitaceae) are important biocontrol agents of Thrips tabaci Lindeman (Thys., Thripidae) in most greenhouses. In this study, we estimated searching time, feeding time and predation rate in O. albidipennis feeding on untreated and treated thrips larvae which had been inoculated with three concentrations of M. anisopliae V275 at four time intervals; 0, 24, 48 and 72 h after infestation. Applied concentrations were 1×103, 2×104 and 2×105 conidia/mL which roughly correspond to the LC25, LC50 and LC75 for second instar-larvae. O. albidipennis responded to the presence of the M. anisopliae on the treated hosts by increasing the searching time and decreasing feeding time and predation rate levels. It was also able to detect and avoid treated patches. 相似文献