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941.
Francesco Caruso Corrado Di Nicola Fabio Marchetti Claudio Pettinari Miriam Rossi Brian W. Skelton 《Inorganica chimica acta》2011,367(1):73-84
New (Q)2SnR2 derivatives (HQ in general; in detail: HQCHPh2 = 4-diphenylacetyl-3-methyl-1-phenyl-5-pyrazolone; HQBn = 3-methyl-1-phenyl-4-phenylacetyl-5-pyrazolone; HQnaph = 3-methyl-4-naphthoyl-1-phenyl-5-pyrazolone; R = CH3, C2H5, C6H11, n- and t-C4H9, C6H5,) have been synthesised and characterised by analytical and spectral techniques. Variable temperature NMR studies of (QCHPh2)2SnR2 derivatives (R = CH3 and C2H5) in chlorohydrocarbon solvents indicate a fluxional behaviour, with rapid interconversion between six- and five-coordinate species, the latter containing a bidentate acylpyrazolonate and a monodentate one. The X-ray crystal structures of the diorganotin(IV) derivatives (QCHPh2)2SnMe2, (QCHPh2)2SnEt2, (QBn)2SnMe2 and , inclusive of a representative of each Qx family, show the metal centres in a skewed trans octahedral configuration. The 4-acyl moiety of the β-diketonate donor exerts a steric effect which is correlated to structural behaviour in the solid and solution state. A solid state 119Sn CPMAS NMR study of the (QBn)2SnR2 (R = CH3, C2H5, t-C4H9 and C6H5) complexes shows a marked deshielding effect and upfield movement of the 119Sn isotropic chemical shift (δiso) through this series. The 119Sn chemical shift spans (Ω) are the largest reported for directly oxo-coordinated Sn(IV) systems, although the markedly reduced Ω value for the (QBn)2SnPh2 complex may be indicative of a cis octahedral coordination, in contrast to the trans octahedral coordination characterising the other complexes of this suite. 相似文献
942.
Barria MA Telling GC Gambetti P Mastrianni JA Soto C 《The Journal of biological chemistry》2011,286(9):7490-7495
Prion diseases are infectious neurodegenerative disorders that affect humans and animals and that result from the conversion of normal prion protein (PrP(C)) into the misfolded prion protein (PrP(Sc)). Chronic wasting disease (CWD) is a prion disorder of increasing prevalence within the United States that affects a large population of wild and captive deer and elk. Determining the risk of transmission of CWD to humans is of utmost importance, considering that people can be infected by animal prions, resulting in new fatal diseases. To study the possibility that human PrP(C) can be converted into the misfolded form by CWD PrP(Sc), we performed experiments using the protein misfolding cyclic amplification technique, which mimics in vitro the process of prion replication. Our results show that cervid PrP(Sc) can induce the conversion of human PrP(C) but only after the CWD prion strain has been stabilized by successive passages in vitro or in vivo. Interestingly, the newly generated human PrP(Sc) exhibits a distinct biochemical pattern that differs from that of any of the currently known forms of human PrP(Sc). Our results also have profound implications for understanding the mechanisms of the prion species barrier and indicate that the transmission barrier is a dynamic process that depends on the strain and moreover the degree of adaptation of the strain. If our findings are corroborated by infectivity assays, they will imply that CWD prions have the potential to infect humans and that this ability progressively increases with CWD spreading. 相似文献
943.
Franck N Morales JP Arancibia-Avendaño D de Cortázar VG Perez-Quezada JF Zurita-Silva A Pastenes C 《The New phytologist》2011,192(4):939-951
We studied the seasonal fluctuation of soil respiration (R(S)), and its root-dependent (R(R)) and basal (R(B)) components, in a Vitis vinifera (Chardonnay) vineyard. The R(S) components were estimated through independent field methods (y-intercept and trenching) and modeled on the basis of a Q(10) response to soil temperature, and fine and coarse root respiration coefficients. The effect of assimilate availability on R(R) was assessed through a trunk girdling treatment. The apparent Q(10) for R(R) was twice that of R(B) (3.5 vs 1.6) and increased linearly with increasing vine root biomass. The fastest R(R) of fine roots was during rapid fruit growth and the fastest R(R) of coarse roots was immediately following fruit development. R(S) was estimated at 32.6 kg ha(-1) d(-1) (69% as a result of R(R) ) for the hottest month and at 7.6 kg ha(-1) d(-1) (18% as a result of R(R)) during winter dormancy. Annual R(S) was low compared with other natural and cultivated ecosystems: 5.4 Mg ha(-1) (46% as a result of R(R)). Our estimates of annual vineyard R(S) are the first for any horticultural crop and suggest that the assumption that they are similar to those of annual crops or forest trees might lead to an overestimation. 相似文献
944.
Maccaferri M Ratti C Rubies-Autonell C Vallega V Demontis A Stefanelli S Tuberosa R Sanguineti MC 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(4):527-544
Soil-borne cereal mosaic (SBCM) is a viral disease, which seriously affects hexaploid as well as tetraploid wheat crops in Europe. In durum wheat
(Triticum durum Desf.), the elite germplasm is characterized by a wide range of responses to SBCMV, from susceptibility to almost complete
resistance. In this study, the genetic analysis of SBCMV resistance was carried out using a population of 181 durum wheat
recombinant inbred lines (RILs) obtained from Meridiano (resistant) × Claudio (moderately susceptible), which were profiled
with SSR and DArT markers. The RILs were characterized for SBCMV response in the field under severe and uniform SBCMV infection
during 2007 and 2008. A wide range of disease reactions (as estimated by symptom severity and DAS-ELISA) was observed. A large
portion of the variability for SBCMV response was explained by a major QTL (QSbm.ubo-2BS) located in the distal telomeric region of chromosome 2BS near the marker triplet Xbarc35–Xwmc661–Xgwm210, with R
2 values ranging from 51.6 to 91.6%. The favorable allele was contributed by Meridiano. Several QTLs with minor effects on
SBCMV response were also detected. Consistently with the observed transgressive segregation, the resistance alleles at minor
QTLs were contributed by both parents. The presence and effects of QSbm.ubo-2BS were validated through association mapping in a panel of 111 elite durum wheat accessions. 相似文献
945.
Peptide therapeutics are of increasing interest due to their biological specificity. We used a simple technique to study the
efficacy of inducing peptides into adherent chondrocytes by transiently permeabilizing the membrane with electric pulses (in
situ electroporation). Mechano-growth factor (MGF) was selected as a model peptide. FITC-labeled MGF was added to cultures
of adherent primary chondrocytes grown on ITO coated glass slides. Cells were subjected to 3–9 pulses of 175–275 V and evaluated
by flow cytometry. Under optimal conditions, an electroporation efficiency of close to 50% could be achieved. This technique
can be used to study the functional domains of intracellular peptides, peptide inhibition of signal transduction and intracrine-mediated
effects of peptides in adherent cells. 相似文献
946.
Gonella E Negri I Marzorati M Mandrioli M Sacchi L Pajoro M Crotti E Rizzi A Clementi E Tedeschi R Bandi C Alma A Daffonchio D 《Applied and environmental microbiology》2011,77(4):1423-1435
One emerging disease of grapevine in Europe is Bois noir (BN), a phytoplasmosis caused by "Candidatus Phytoplasma solani" and spread in vineyards by the planthopper Hyalesthes obsoletus (Hemiptera: Cixiidae). Here we present the first full characterization of the bacterial community of this important disease vector collected from BN-contaminated areas in Piedmont, Italy. Length heterogeneity PCR and denaturing gradient gel electrophoresis analysis targeting the 16S rRNA gene revealed the presence of a number of bacteria stably associated with the insect vector. In particular, symbiotic bacteria detected by PCR with high infection rates in adult individuals fell within the "Candidatus Sulcia muelleri" cluster in the Bacteroidetes and in the "Candidatus Purcelliella pentastirinorum" group in the Gammaproteobacteria, both previously identified in different leafhoppers and planthoppers. A high infection rate (81%) was also shown for another symbiont belonging to the Betaproteobacteria, designated the HO1-V symbiont. Because of the low level of 16S rRNA gene identity (80%) with the closest relative, an uncharacterized symbiont of the tick Haemaphysalis longicornis, we propose the new name "Candidatus Vidania fulgoroideae." Other bacterial endosymbionts identified in H. obsoletus were related to the intracellular bacteria Wolbachia pipientis, Rickettsia sp., and "Candidatus Cardinium hertigii." Fluorescent in situ hybridization coupled with confocal laser scanning microscopy and transmission electron microscopy showed that these bacteria are localized in the gut, testicles, and oocytes. As "Ca. Sulcia" is usually reported in association with other symbiotic bacteria, we propose that in H. obsoletus, it may occur in a bipartite or even tripartite relationship between "Ca. Sulcia" and "Ca. Purcelliella," "Ca. Vidania," or both. 相似文献
947.
Juliana Pereira Lyon Fábio Vieira dos Santos Pedro Claudio Guaranho de Moraes Leonardo Marmo Moreira 《Mycopathologia》2011,171(2):93-101
Candida yeasts are opportunistic pathogens responsible for infections in immunocompromised individuals. Among the virulence factors
present in these yeasts we can mention the ability to adhere to host cells, exoenzyme production and germ tube formation.
Several compounds, such as antifungal agents, plants extracts, protein inhibitors and surfactants, have been tested regarding
their capacity in inhibit Candida spp. virulence factors. Among these compounds, a significant lower number of works are focused on the inhibition action caused
by different types of surfactant. The present work aimed to evaluate the effect generated by the surfactants cetyltrimethylammonium
chloride (CTAC), sodium dodecyl sulfate (SDS), N-hexadecyl-N–N′-dimethyl-3-ammonio-1-propane-sulfonate (HPS) and octylphenoxypolyethoxyethanol (Triton X-100) on the viability, adhesion
ability and exoenzyme production by Candida species. CTAC and HPS were capable to inhibit Candida spp. growth at very low concentrations. All surfactants demonstrated to be capable to inhibit the adhesion of Candida species to buccal epithelial cells (BEC) and the proteinase production. On the other hand, the phospholipase production remained
unaltered after the treatment with these compounds. The present data denote that cationic and zwitterionic surfactants are
interesting prototypes of inhibitory agents against Candida spp., which is probably associated with the cationic punctual charge of both surfactants. The results are discussed in details
in agreement with recent reports from literature. 相似文献
948.
949.
Ceconi C Comini L Suffredini S Stillitano F Bouly M Cerbai E Mugelli A Ferrari R 《American journal of physiology. Heart and circulatory physiology》2011,300(1):H366-H373
The aim of this study was to investigate the effect of chronic heart rate (HR) reduction with the hyperpolarization-activated current inhibitor ivabradine on the global phenotype of left ventricular (LV) remodeling in a ligated rat model. Seven days after coronary artery ligation, Wistar rats received ivabradine (10 mg · kg(-1) · day(-1) administered in drinking water) [myocardial infarction + ivabradine (MI+IVA), n = 22] or vehicle only (drinking water) (MI, n = 20) for 90 days. A sham group (n = 20) was included for model validation. MI+IVA rats had 12% lower HR (P < 0.01), improved LV volumes, 15% higher LV ejection fraction (LVEF, P < 0.01) than MI rats, and 33% reductions in both plasma atrial natriuretic peptide (ANP, P = 0.052) and cardiac hydroxyproline. Using patch-clamp, action potential duration was reduced and transient outward current density increased (P < 0.05). Cardiac energy metabolism was also improved (+33% creatine phosphate, P < 0.001; +15% ATP; and +9% energy charge, P < 0.05). Significant correlations were found between HR and parameters of cardiac metabolism, ANP, and LVEF (all P < 0.05). The HR-reducing properties of ivabradine prevent changes in the global phenotype of LV remodeling in the rat, optimize energy consumption, and avoid electrophysiological and structural remodeling. 相似文献
950.
Several studies have suggested that triadin (Tdn) may be a critical component of skeletal EC-coupling. However, using Tdn-null mice we have shown that triadin ablation results in no significant disruption of skeletal EC-coupling. To analyze the role of triadin in EC-coupling signaling here we used whole-cell voltage clamp and simultaneous recording of intracellular Ca2+ release to characterize the retrograde and orthograde signaling between RyR1 and DHPR in cultured myotubes. DHPR Ca2+ currents elicited by depolarization of Wt and Tdn-null myotubes displayed similar current densities and voltage dependence. However, kinetic analysis of the Ca2+ current shows that activation time constant of the slow component was slightly decreased in Tdn-null cells. Voltage-evoked Ca2+ transient of Tdn-null myotubes showed small but significant reduction in peak fluorescence amplitude but no differences in voltage dependence. This difference in Ca2+ amplitude was averted by over-expression of FKBP12.6. Our results show that bi-directional signaling between DHPR and RyR1 is preserved nearly intact in Tdn-null myotubes and that the effect of triadin ablation on Ca2+ transients appears to be secondary to the reduced FKBP12 binding capacity of RyR1 in Tdn-null myotubes. These data suggest that skeletal triadins do not play a direct role in skeletal EC-coupling. 相似文献