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91.
Variations in apparent diffusion coefficient of water (ADC) and blood-brain barrier (BBB) permeability after ischemia have been suggested, though the correlation between ADC alterations and BBB opening remains to be studied. We hypothesized that there are correlations between the alteration of ADC and BBB permeability. Rats were subjected to 2 h of transient middle cerebral artery occlusion and studied at 3 and 48 h of reperfusion, which are crucial times of BBB opening. BBB permeability and ADC values were measured by dynamic contrast-enhanced MRI and diffusion-weighted imaging, respectively. Temporal and spatial analyses of the evolution of BBB permeability and ADC alteration in cortical and subcortical regions were conducted along with the correlation between ADC and BBB permeability data. We found significant increases in BBB leakage and reduction in ADC values between 3 and 48 h of reperfusion. We identified three MR tissue signature models: high Ki and low ADC, high Ki and normal ADC, and normal Ki and low ADC. Over time, areas with normal Ki and low ADC transformed into areas with high Ki. We observed a pattern of lesion evolution where the extent of initial ischemic injury reflected by ADC abnormalities determines vascular integrity. Our results suggest that regions with vasogenic edema alone are not likely to develop low ADC by 48 h and may undergo recovery. 相似文献
92.
93.
The friendly and aggressive behaviors directed by females other than the mother to the troop's infants were recorded during
a six-month long study of stumptail macaques living on an island. A great deal of friendly contacts were directed by the females
toward the troop's infants. Juvenile females interacted with infants mainly through social play while adult females directed
passive contacts (e.g., touch-hand) to them. While the adult females displayed more care contacts toward male infants the
juvenile females preferred the female infants. The social position of the infant's mother in the troop and the attention it
received from the males regulated the caring behavior an infant received from the females. 相似文献
94.
95.
96.
Francesca Rappa Alessandro Pitruzzella Antonella Marino Gammazza Rosario Barone Emanuele Mocciaro Giovanni Tomasello Francesco Carini Felicia Farina Giovanni Zummo Everly Conway de Macario Alberto JL Macario Francesco Cappello 《Cell stress & chaperones》2016,21(5):927-933
Large bowel carcinogenesis involves accumulation of genetic alterations leading to transformation of normal mucosa into dysplasia and, lastly, adenocarcinoma. It is pertinent to elucidate the molecular changes occurring in the pre-neoplastic lesions to facilitate early diagnosis and treatment. Heat shock proteins (Hsps), many of which are molecular chaperones, are implicated in carcinogenesis, and their variations with tumor progression encourage their study as biomarkers. There are many reports on Hsps and cancer but none to our knowledge on their systematic quantification in pre-neoplastic lesions of the large bowel. We performed immunohistochemical determinations of Hsp10, Hsp60, Hsp70, and Hsp90 in biopsies of large bowel tubular adenomas with moderate grade of dysplasia and compared to normal mucosa and adenocarcinoma with a moderate grade of differentiation (G2). A significant elevation of Hsp10 and Hsp60 only, i.e., in the absence of elevation of Hsp70 or Hsp90, in both epithelium and lamina propria was found in tubular adenoma by comparison with normal mucosa. In contrast, adenocarcinoma was characterized by the highest levels of Hsp10 and Hsp60 in epithelium and lamina propria, accompanied by the highest levels of Hsp70 only in epithelium and of Hsp90 only in lamina propria, by comparison with normal and tubular adenoma counterparts. Hsp10 and Hsp60 are promising biomarkers for early diagnosis of tubular adenoma and for its differentiation from more advanced malignant lesions. Hsp10 and Hsp60 may be implicated in carcinogenesis from its very early steps and, thus, are potentially convenient targets for therapy. 相似文献
97.
Spatio-temporal variability of the winter phytoplankton distribution across the Catalan and North Balearic fronts (NW Mediterranean) 总被引:1,自引:0,他引:1
The qualitative and quantitative composition of the phytoplankton
assemblages of the Catalano-Balearic Sea (NW Mediterranean) was examined in
relationship with frontal boundaries and short-term meteorological forcing
originated by an intense wind storm. Data were obtained during February
1990, before and after strong NW winds, from several transects across the
Catalan (continental side) and North Balearic (Balearic Islands side)
shelf/slope fronts. High chlorophyll concentrations and diatom dominance
inshore of the Catalan Front were typical of the winter-spring
phytoplankton maximum. However, offshore of the Catalan Front, diatoms were
scarce and the phytoplankton assemblage was dominated by coccolithophorids.
In spite of weak density stratification, a deep chlorophyll maximum (DCM)
was well developed, before the storm, offshore and appeared to cause a
pulse of new production, as suggested by increased oxygen concentrations in
the vicinity of the DCM. The results presented here indicate the existence
of a persistent association between the distribution of distinct
phytoplankton assemblages and hydrographic characteristics of the studied
area. Our results also show that, at least during an important part of the
winter-spring bloom period of the Catalano-Balearic Sea, high phytoplankton
biomass offshore of the Catalan Front is not associated with the diatom
dominance typically found in coastal waters and other offshore areas of the
NW Mediterranean. This finding has biogeochemical implications in
relationship with vertical export fluxes of particulate matter.
相似文献
98.
Safety Evaluation of Transgenic Tilapia with Accelerated Growth 总被引:2,自引:0,他引:2
Isabel Guillén Jorge Berlanga Carmen M. Valenzuela Antonio Morales José Toledo Mario P. Estrada Pedro Puentes Orlando Hayes José de la Fuente 《Marine biotechnology (New York, N.Y.)》1999,1(1):2-14
Recent advances in modern marine biotechnology have permitted the generation of new strains of economically important fish
species through the transfer of growth hormone genes. These transgenic fish strains show improved growth performance and therefore
constitute a better alternative for aquaculture programs. Recently, we have obtained a transgenic tilapia line with accelerated
growth. However, before introducing this line into Cuban aquaculture, environmental and food safety assessment was required
by national authorities. Experiments were performed to evaluate the behavior of transgenic tilapia in comparison to wild tilapia
as a way to assess the environmental impact of introducing transgenic tilapia into Cuban aquaculture. Studies were also conducted
to evaluate, according to the principle of substantial equivalence, the safety of consuming transgenic tilapia as food. Behavior
studies showed that transgenic tilapia had a lower feeding motivation and dominance status than controls. Food safety assessment
indicated that tilapia growth hormone has no biological activity when administered to nonhuman primates. Furthermore, no effects
were detected in human healthy volunteers after the consumption of transgenic tilapia. These results showed, at least under
the conditions found in Cuba, no environmental implications for the introduction of this transgenic tilapia line and the safety
in the consumption of tiGH-transgenic tilapia as an alternative feeding source for humans. These results support the culture
and consumption of these transgenic tilapia.
Received: March 9, 1998; accepted June 25, 1998. 相似文献
99.
In Neotropical rain forests, fresh mammal dung, especially that of howler monkeys, constitutes an important resource used by dung beetles as food and for oviposition and further feeding by their larvae. Tropical rain forest destruction, fragmentation, and subsequent isolation causing reductions in numbers of and the disappearance of howler moneys may result in decreasing numbers of dung beetles, but this has not been documented. In this study, we present information on the presence of howlers and dung beetles in 38 isolated forest fragments and 15 agricultural habitats. Howler monkeys were censused by visual means, while dung beetles were sampled with traps baited with a mixture of howler, cow, horse, and dog dung. Results indicated that loss of area and isolation of forest fragments result in significant decrements in howlers and dung beetles. However, dung beetle abundance was found to be closely related to the presence of howler monkeys at the sites and habitats investigated. Scenarios of land management designed to reduce isolation among forest fragments may help sustain populations of howler monkeys and dung beetles, which may have positive consequences for rain forest regeneration. Am. J. Primatol. 48:253–262, 1999. © 1999 Wiley‐Liss, Inc. 相似文献
100.
Lendvai G Velikyan I Estrada S Eriksson B Långström B Bergström M 《Oligonucleotides》2008,18(1):33-49
In vivo monitoring of gene expression may be accomplished using a most advanced imaging technology such as positron emission tomography (PET). However, a range of methodological and biological hurdles needs exploration. In the present study, 20-mer DNA-LNA (locked nucleic acid) mixmer oligonucleotides specific for rat Chromogranin-A (Chg-A) mRNA were labeled with 68Ga and their biodistribution were investigated in rats; namely, two Antisense (LNA1, LNA2--differing only in the positioning of LNA modification), Mismatched, and Sense sequences. In addition, in vivo and in vitro metabolite analysis of LNA1 and LNA2 was compared, and hybridization in solution was performed to verify the hybridization ability after labeling. Furthermore, semiquantitative polymerase chain reaction was carried out to find organs expressing Chg-A mRNA in the rat. The biodistribution patterns altered according to the sequence and the positioning of LNA modification. The pattern of Mismatched--differing only in two nucleotides from the two Antisenses--was similar to that of Sense, whereas the pattern of LNA1 and LNA2 showed differences. Uptake in the adrenal gland was twofold higher with LNA2 compared to the other three oligonucleotides. Intact LNA2 could be observed in the 60-minute sample in vivo, whereas in vitro, the intact compound of both Antisenses could also be detected after 2 hours. Hybridization in solution revealed that the two Antisenses retained their hybridization abilities after 68Ga-labeling. With decreasing magnitude, Chg-A mRNA was expressed in the adrenal gland, intestine, testis, and pancreas. This study further supported LNA-DNA mixmer to be a favorable modification for antisense targeting approach with respect to hybridization and longer plasma residence; however, the organ uptake was dominated by processes irrelevant to specific hybridization. 相似文献