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961.
Seven-day volumetric spore samplers were installed in pear orchards of northern Italy, in the years between 1993 and 2002,
and operated continuously during the development of brown spot epidemics (mid-April–mid-August), caused by Stemphylium vesicarium. Aerial concentration of conidia was recorded at 2 h intervals to study their diurnal and seasonal patterns and the influence
of weather conditions. The diurnal periodicity of aerial conidia showed a peak around midday and low counts in the dark. The
increase in spore concentration was significantly correlated with the reduction of relative humidity and wetness in early
morning, and the increase of wind in late morning and afternoon. Conidia of S. vesicarium became easily airborne to form a regular component of the air-spora in pear orchards, while ascospores were caught only sporadically.
Differences between years concerned total spore counts and numbers of peaks (defined as days with more than 30 conidia/m3 air per day). Periods with highest spore counts occurred in late-May to early-June (in 2 years), mid to end of June (5 years),
or after mid-July (3 years). There was a significant correlation between spore peaks and days with favourable weather conditions,
defined as days with air temperature between 15 and 25°C and high humidity, particularly a wet period longer than 10 h. Occurrence
of one or more consecutive days with favourable weather conditions determined an increase in the airborne concentration of
conidia, which usually lasted some days and then decreased. 相似文献
962.
Summary Histophotometric examination was carried out on nuclei of lymphocytes in human peripheral blood, which were subjected to various tests in order to assess the acrolein-Schiff method as a possible DNA specific reaction, in comparison with the traditional Feulgen reaction. Special attention was paid to the degree of difference between responses attributable to a direct Schiff reaction obtained in the fraction of nuclear proteins after treatment with acrolein. From the results obtained it appears that an acrolein-Schiff reaction, following extraction of proteins, may be considered a qualitative reaction for DNA. Our findings also show that there is no relationship between the degree of response to the acrolein-Schiff reaction and that to the Feulgen reaction, which is to be expected in view of the different mechanisms of the two reactions. 相似文献
963.
Dr. Giancarlo Pizza Dimitri Viza Caterina De Vinci Aldopaolo Palareti Diego Cuzzocrea Vittorio Fornarola Roberto Baricordi 《Biotherapy》1996,9(1-3):67-72
Forty-four patients suffering from genital (22) and labial (22) herpes were orally treated with HSV-1/2-specific transfer
factor(TF). TF was obtained by in vitro replication of a HSV-1/2-specific bovine dialysable lymphocyte extract. Treatment
was administered bi-weekly the first 2 weeks, and then weekly for 6 months, most patients received 2–3 courses. The total
observation period for all patients before treatment was 26660 days, with 544 relapses, and a relapse index of 61.2, whereas
the cumulative observation period during and after treatment was 16945 days, with a total of 121 relapsing episodes and a
cumulative RI of 21.4 (P<0.0001). Results were equally significant when the 2 groups of patients (labial and genital) were
considered separately. These observations confirm previous results obtained with bovine HSV-specific TF, and warrant further
studies to establish HSV-specific TF as a choice of treatment for preventing herpes recurrences. 相似文献
964.
Vittorio Gremigni 《Journal of morphology》1976,149(2):265-277
Oogenesis of the fresh-water triclad Dugesia dorotocephala has been studied by electron microscopical methods, with particular regard to the genesis and composition of the so-called “Balbiani body.” Its origin is clearly recognizable in young oocytes where the few mitochondria present seem to gather at the level of the perinuclear ooplasm. Here they surround dense masses of finely granular, fibrillar material probably coming from the nucleus. During the previtelloge ic period, mitochondria rapidly increase in number while the dense masses progressively dissolve. In the vitellogenic oocytes the Balbiani body shows its final configuration: it appears as a large area (up to 15-20 pm in diameter) consisting of innumerable densely packed mitochondria, some smooth vesicles and free ribosomes. This aggregate of cytoplasmic organelles remains unmodified in the mature oocytes. The function of the “Balbiani body” of D. dorotocephala is as yet unclear; it can only be asserted that it is not correlated with yolk production in which the endoplasmic reticulum and the Golgi complex are involved. 相似文献
965.
966.
Raffaele Porta Marina Camardella Vittorio Gentile Antonio De Santis 《Journal of neurochemistry》1984,42(2):321-325
Since a specific inhibition of cerebral spermidine (Spd) synthase activity by alicyclic amines was preliminarily observed in vitro, we examined the in vivo inhibitory effectiveness of dicyclohexylamine (DCHA) on Spd biosynthesis in 21-day-old rat brain. For this purpose a previously reported HPLC procedure (Porta et al., 1981a) was modified to analyze the cerebral levels of DCHA at the time of polyamine determinations. The intraperitoneally injected DCHA was shown to cross the blood-brain barrier easily, reaching high levels in the cerebral tissue (approximately 750 nmol/g brain) within 1 h of its administration. The effect of the drug on the polyamine metabolism resulted in a significant depletion of Spd biosynthesis from the sixth hour after the treatment and in an earlier and prolonged increase of the putrescine (Pt) steady-state levels. Conversely, the spermine (Spm) endogenous pools remained unchanged throughout the 24-h post-DCHA period. Moreover, following the intracerebral administration of [1,4-14C]Pt, significantly lower specific radioactivity (s.r.a.) values for labeled Pt and Spd were recorded in the brains of DCHA-treated animals. Conversely, after intracerebral [14C]Spd injection, the s.r.a. of newly formed [14C]Spm remained unchanged, confirming the specificity of the DCHA effect on the Spd biosynthesis. 相似文献
967.
968.
Tongue movements during speech production have been investigated by means of a simple yet realistic biomechanical model,
based on a finite elements modeling of soft tissues, in the framework of the equilibrium point hypothesis (-model) of motor control. In particular, the model has been applied to the estimation of the “central” control commands issued
to the muscles, for a data set of mid-sagittal digitized tracings of vocal tract shape, r
ecorded by means of low-intensity X-ray cineradiographies during speech. In spite of the highly non-linear mapping between
the shape of the oral cavity and its acoustic consequences, the organization of control commands preserves the peculiar spatial
organization of vowel phonemes in acoustic space. A factor analysis of control commands, which have been decomposed into independent
or “orthogonal” muscle groups, has shown that, in spite of the great mobility of the tongue and the highly
complex arrangement of tongue muscles, its movements can be explained in terms of the activation of a small number of independent
muscle groups, each corresponding to an elementary or “primitive” movement. These results are consistent with the hypothesis
that the tongue is controlled by a small number of independent “articulators”, for which a precise biomechanical substrate
is provided. The influence of the effect of jaw and hyoid movements on tongue equilibrium has also bee
n evaluated, suggesting that the bony structures cannot be considered as a moving frame of reference, but, indeed, there may
be a substantial interaction between them and the tongue, that may only be accounted for by a “global” model. The reported
results also define a simple control model for the tongue and, in analogy with similar modelling studies, they suggest that,
because of the peculiar geometrical arrangement of tongue muscles, the central nervous system (CNS) may not need a de
tailed representation of tongue mechanics but rather may make use of a relatively small number of muscle synergies, that are
invariant over the whole space of tongue configurations.
Received: 27 August 1996 / Accepted in revised form: 25 February 1997 相似文献
969.
Marisa Berti Roberto Scotti Franca Ripamonti Vittorio Arioli 《Current microbiology》1979,2(4):223-225
The activity of the combination rifampin plus trimethoprim againstHaemophilus influenzae was studied from the point of view of synergism, bactericidal activity, and inhibition of the selection of rifampin-resistant
cells. At concentrations of the two drugs that are easily attainable in human serum after oral treatment with 600 mg of rifampin
plus 160 mg of trimethoprim, the combination acted synergistically on all of the strains tested, was remarkably bactericidal,
and inhibited the selection of rifampin-resistant cells. 相似文献
970.
Amino acid release studies were performed by an HPLC procedure using differentiated rat cerebellar granule cell cultures. Kainic acid (KA; 50 microM) caused an increase (about threefold) in the release of endogenous glutamate and a lesser, but statistically significant, increase in the release of glutamine, glycine, threonine, taurine, and alanine. Quisqualic acid (QA) and, to a lesser degree, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) (both 50 microM) enhanced the release of the following amino acids in the order glutamate greater than aspartate greater than or equal to taurine, whereas the release of other amino acids was either unaffected or affected in a statistically nonsignificant way. The release of glutamate induced by KA was partially (43%) Ca2+ dependent. The other release-inducing effects of KA and QA were not Ca2+ dependent. In all cases, the evoked release could be prevented by the non-N-methyl-D-aspartate (non-NMDA) receptor antagonist 6-cyano-2,3-hydroxy-7-nitroquinoxaline, and thus appeared to be receptor mediated. NMDA (5 and 50 microM) had no release-inducing activity. The KA-, QA-, and AMPA-evoked release of newly synthesized [3H]glutamate and [3H]aspartate (formed in the cells exposed to [3H]glutamine) was very similar to the evoked release of endogenous glutamate and aspartate. On the other hand, the release of preloaded D-[3H]aspartate (purified by HPLC in the various fractions analyzed, before radioactivity determination) induced by 50 microM KA was twice as high as that of endogenous glutamate. In the case of high [K+] depolarization, in contrast, the release of preloaded D-[3H]aspartate was approximately 30% lower than that of endogenous glutamate.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献