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991.
López-Guillén G Cruz-López L Malo EA González-Hernández H Cazares CL López-Collado J Toledo J Rojas JC 《Environmental entomology》2008,37(4):876-882
During sexual signaling, males of Anastrepha obliqua (Macquart) form leks and attract females by producing sounds and releasing volatile compounds. The objective of this study was to investigate the influence time of time of day, age, irradiation, mating status, and the presence of host fruit on the release of volatile components by laboratory-reared A. obliqua males. A. obliqua males released four compounds identified by gas chromatography coupled with mass spectrometry (GC-MS) as (E,E)-alpha-farnesene, (Z,E)-alpha-farnesene, (Z)-3-nonenol, and a farnesene isomer during calling behavior. Although males released volatiles during the entire day, the amount of volatiles was higher in the early morning and afternoon hours. Males began to emit volatiles when they were 6 d old, but only the amount of (Z)-3-nonenol was affected by age. Irradiation of flies with gamma rays from a (60)Co source at a dose rate of 0.8 Gy significantly reduced the amount of volatiles released during calling behavior. The amount of volatiles was lower in recently mated males than virgin males. However, there were no significant differences between virgin males and males 24 h after mating. The presence of host fruit did not affect the amount of volatiles compared with the control. 相似文献
992.
Stem and leaf hydraulics of congeneric tree species from adjacent tropical savanna and forest ecosystems 总被引:1,自引:0,他引:1
Hao GY Hoffmann WA Scholz FG Bucci SJ Meinzer FC Franco AC Cao KF Goldstein G 《Oecologia》2008,155(3):405-415
Leaf and stem functional traits related to plant water relations were studied for six congeneric species pairs, each composed
of one tree species typical of savanna habitats and another typical of adjacent forest habitats, to determine whether there
were intrinsic differences in plant hydraulics between these two functional types. Only individuals growing in savanna habitats
were studied. Most stem traits, including wood density, the xylem water potential at 50% loss of hydraulic conductivity, sapwood
area specific conductivity, and leaf area specific conductivity did not differ significantly between savanna and forest species.
However, maximum leaf hydraulic conductance (K
leaf) and leaf capacitance tended to be higher in savanna species. Predawn leaf water potential and leaf mass per area were also
higher in savanna species in all congeneric pairs. Hydraulic vulnerability curves of stems and leaves indicated that leaves
were more vulnerable to drought-induced cavitation than terminal branches regardless of genus. The midday K
leaf values estimated from leaf vulnerability curves were very low implying that daily embolism repair may occur in leaves. An
electric circuit analog model predicted that, compared to forest species, savanna species took longer for their leaf water
potentials to drop from predawn values to values corresponding to 50% loss of K
leaf or to the turgor loss points, suggesting that savanna species were more buffered from changes in leaf water potential. The
results of this study suggest that the relative success of savanna over forest species in savanna is related in part to their
ability to cope with drought, which is determined more by leaf than by stem hydraulic traits. Variation among genera accounted
for a large proportion of the total variance in most traits, which indicates that, despite different selective pressures in
savanna and forest habitats, phylogeny has a stronger effect than habitat in determining most hydraulic traits. 相似文献
993.
Concepción José-Nuñez Alfredo Torres-Larios Leticia Ramírez-Silva Guillermo Mendoza Guillermo Salcedo Armando Gómez-Puyou Marietta Tuena de Gómez-Puyou 《Journal of bioenergetics and biomembranes》2008,40(6):561-568
Although the capacity of isolated β-subunits of the ATP synthase/ATPase to perform catalysis has been extensively studied,
the results have not conclusively shown that the subunits are catalytically active. Since soluble F1 of mitochondrial H+-ATPase can bind inorganic pyrophosphate (PPi) and synthesize PPi from medium phosphate, we examined if purified His-tagged β-subunits from Thermophilic bacillus PS3 can hydrolyze PPi. The difference spectra in the near UV CD of β-subunits with and without PPi show that PPi binds to the subunits. Other studies show that β-subunits hydrolyze [32P] PPi through a Mg2+-dependent process with an optimal pH of 8.3. Free Mg2+ is required for maximal hydrolytic rates. The Km for PPi is 75 μM and the Vmax is 800 pmol/min/mg. ATP is a weak inhibitor of the reaction, it diminishes the Vmax and increases the
Km for PPi. Thus, isolated β-subunits are catalytically competent with PPi as substrate; apparently, the assembly of β-subunits into the ATPase complex changes substrate specificity, and leads to
an increase in catalytic rates. 相似文献
994.
Pedro D. Arini Guillermo C. Bertrn Esteban R. Valverde Pablo Laguna 《Biomedical signal processing and control》2008,3(1):67-77
This study examined the significance of ECG-derived indexes in quantifying ventricular repolarization dispersion (VRD) given its value as a risk marker for severe myocardial arrhythmia. Multilead ECG recordings from an isolated rabbit heart model, including control and globally increased VRD (IVRD) beats, were studied. The IVRD was induced by supplying d-Sotalol (DS) or premature ventricular stimulation (PVS). ECG indexes came from (a) the absolute ECG summation signal, from which we obtained the amplitude and area of the T-wave, and the T-wave width (TW), which we consider as IVRD indexes, and (b) the Singular Value Decomposition (SVD) of the ECG, from which the θPT (angle between the first SVD principal axis and the repolarization axis), T-wave residuum (TWR), T-wave morphology dispersion (TMD), unnormalized TMD (UTMD), and θRT (the angle between the depolarization and the repolarization vectors) were estimated as IVRD indexes. Results were compared with the classical QT-based VRD indexes (σQTe, standard deviation of QT end). The main results are TW: 78.0±10.3 vs. 133.6±29.6 ms, for control vs. IVRD generated using DS, p<0.005 and 95.2±7.9 vs. 118.5±15.7 ms when PVS was used, p<0.007; σQTe: gives 6.5±1.4 vs. 11.6±1.9 ms, for DS p<0.007 and 7.6±2.2 vs. 13.0±3.4 ms for PVS, p<0.007; respectively. θPT: 35±51° vs. 117±49°, p<0.009 in DS. We concluded that globally induced IVRD is well reflected by the TW parameter, being the most sensitive of the studied ones. The IVRD can also be quantified by using the θPT index. 相似文献
995.
María Álvarez‐Satta Sheila Castro‐Sánchez Guillermo Pousada Diana Valverde 《Journal of cellular and molecular medicine》2017,21(10):2268-2275
Bardet–Biedl syndrome (BBS) and Alström syndrome (ALMS) are rare diseases belonging to the group of ciliopathies. Although mutational screening studies of BBS/ALMS cohorts have been extensively reported, little is known about the functional effect of those changes. Thus, splicing variants are estimated to represent 15% of disease‐causing mutations, and there is growing evidence that many exonic changes are really splicing variants misclassified. In this study, we aimed to analyse for the first time several variants in BBS2, ARL6/BBS3, BBS4 and ALMS1 genes predicted to produce aberrant splicing by minigene assay. We found discordance between bioinformatics analysis and experimental data when comparing wild‐type and mutant constructs. Remarkably, we identified nonsense variants presumably resistant to nonsense‐mediated decay, even when a premature termination codon would be introduced in the second amino acid (p.(G2*) mutation in ARL6/BBS3 gene). As a whole, we report one of the first functional studies of BBS/ALMS1 variants using minigene assay, trying to elucidate their role in disease. Functional studies of variants identified in BBS and ALMS patients are essential for their proper classification and subsequent genetic counselling and could also be the start point for new therapeutic approaches, currently based only on symptomatic treatment. 相似文献
996.
Germán Garrote José Francisco Bueno Manuel Ruiz Santiago de Lillo José Manuel Martín Guillermo López Miguel Ángel Simón 《European Journal of Wildlife Research》2017,63(5):79
According to literature, female Iberian lynx (Lynx pardinus) start reproducing at 3 years of age. In more recent years, females breeding at 2 years have been recorded in wild populations. Here, however, we describe the first breeding record for a one-year-old female Iberian lynx. This finding was obtained by camera-trapping data, provided by the yearly monitorization of the species that is carried out across its distribution area. A litter of two lynx kittens was found at the south-east limit of the Andujar-Cardeña population. Two camera-traps were set up near the den to identify the breeding female. Photographs obtained confirmed that the breeding female had already been identified the previous year at less than 3 months of age. The case reported here of a yearling female breeding is the first ever from historical distribution range of the species, and as such, is an exceptional event in the reproduction of the Iberian lynx. 相似文献
997.
Jaquelina?Sánchez-Ramírez José?L.?Martínez-Hernández Patricia?Segura-Ceniceros Guillermo?López Hened?Saade Miguel?A.?Medina-Morales Rodolfo?Ramos-González Cristóbal?N.?Aguilar Anna?IlyinaEmail author 《Bioprocess and biosystems engineering》2017,40(1):9-22
In the present study, Trichoderma reesei cellulase was covalently immobilized on chitosan-coated magnetic nanoparticles using glutaraldehyde as a coupling agent. The average diameter of magnetic nanoparticles before and after enzyme immobilization was about 8 and 10 nm, respectively. The immobilized enzyme retained about 37 % of its initial activity, and also showed better thermal and storage stability than free enzyme. Immobilized cellulase retained about 80 % of its activity after 15 cycles of carboxymethylcellulose hydrolysis and was easily separated with the application of an external magnetic field. However, in this reaction, K m was increased eight times. The immobilized enzyme was able to hydrolyze lignocellulosic material from Agave atrovirens leaves with yield close to the amount detected with free enzyme and it was re-used in vegetal material conversion up to four cycles with 50 % of activity decrease. This provides an opportunity to reduce the enzyme consumption during lignocellulosic material saccharification for bioethanol production. 相似文献
998.
TRPV4 Regulates Tight Junctions and Affects Differentiation in a Cell Culture Model of the Corneal Epithelium
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999.
Eva?C.?Rueda Kerry?A.?Mullaney Cecilia?Conte-Grand Evelyn?M.?Habit Víctor?Cussac Guillermo?OrtíEmail author 《Biological invasions》2017,19(3):971-988
The Patagonian silverside Odontesthes hatcheri is a native fish restricted to streams and lakes of Patagonia (Argentina and Chile). Stocking programs to enhance recreational fisheries in man-made reservoirs have introduced a nonnative, closely-related species (the pejerrey O. bonariensis) in Patagonia almost a century ago, and yet little is known about the invasiveness of this species. To evaluate the impact of these introductions we analyze genetic data (microsatellite markers and mitochondrial DNA) to quantify the incidence of hybridization between these two species and assess potential effects on native population structure. Phylogeographic analyses reveal weak geographic differentiation among populations of O. hatcheri, in agreement with previous studies for other freshwater fishes in Patagonia strongly influenced by Quaternary glaciations and hydrographic basin changes since the last glaciation. However, many populations have unique genetic pools. In several areas, introductions resulted in extensive hybridization, with high frequencies of F2 and backcrossed hybrids in natural populations, and in some cases O. bonariensis has completely displaced the native populations. The negative impact of these introductions on native populations is correlated to temperature, a critical parameter in the face of global warming, suggesting that invasiveness of O. bonariensis may increase in the future. Our results advise against continuing stocking programs to preserve the integrity of natural populations of the Patagonian silverside. 相似文献
1000.
In this paper, we propose a novel multi-objective ant colony optimizer (called iMOACO\(_{\mathbb {R}}\)) for continuous search spaces, which is based on ACO\(_{\mathbb {R}}\) and the R2 performance indicator. iMOACO\(_{\mathbb {R}}\) is the first multi-objective ant colony optimizer (MOACO) specifically designed to tackle continuous many-objective optimization problems (i.e., multi-objective optimization problems having four or more objectives). Our proposed iMOACO\(_{\mathbb {R}}\) is compared to three state-of-the-art multi-objective evolutionary algorithms (NSGA-III, MOEA/D and SMS-EMOA) and a MOACO algorithm called MOACO\(_{\mathbb {R}}\) using standard test problems and performance indicators taken from the specialized literature. Our experimental results indicate that iMOACO\(_{\mathbb {R}}\) is very competitive with respect to NSGA-III and MOEA/D and it is able to outperform SMS-EMOA and MOACO\(_{\mathbb {R}}\) in most of the test problems adopted. 相似文献