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71.
Toshitaka Iwamoto Akio Mori Masao Kawai Afework Bekele 《Primates; journal of primatology》1996,37(4):389-397
The anti-predator behavior of gelada baboons has been observed to consist of simple flight (i.e. they flee to cliffs after
becoming alarmed by potential predators). However, active antipredator behavior was observed in a recently found gelada population
in Arsi, Ethiopia. This population showed frequent active counter-attacks and severe mobbing at predators. Males fought domestic
dogs on the plain and exhibited a systematic mobbing behavior towards a leopard on the cliff face to chase it off. These active
anti-predator behaviors are the first confirmed reports on gelada baboons and may provide a useful insight for the understanding
of the process of evolutionary adaptation to highland habitats by gelada baboons, as well as for the origin of this small
southern population. 相似文献
72.
APieris melete male emits species-specific scent from the wings, while a virgin female ofP. melete is frequently observed to take the so-called “mate-refusal posture” in response to courting males. The role of the male scent
in the mating behavior ofP. melete was investigated experimentally by using scented and scentless male models. It is suggested that the male wing scent can
function primarily as a sex pheromone to “seduce” the virgin females that assume the mate-refusal posture, and can therefore
induce a successful copulation.
This work was financially supported by the Japan Society for the Promotion of Science. 相似文献
73.
Hiroko Ogawa Toshitaka Oohashi Masataka Sata Yoko Bekku Satoshi Hirohata Keigo Nakamura Tomoko Yonezawa Shozo Kusachi Yasushi Shiratori Yoshifumi Ninomiya 《Matrix biology》2004,23(5):287-298
Link proteins (LPs) belong to the link-module superfamily, which can stabilize and enhance the binding of lecticans to hyaluronan. We report here the identification and characterization of a novel rat link protein gene (Lp3/Hapln3). The deduced protein sequence shares the typical modular elements of link proteins and has an estimated mass of 39 kDa. Examination of the rat genomic DNA sequence revealed that Lp3/Hapln3 and aggrecan genes were paired on chromosome 1q31. Another LP gene and the lectican gene were also paired at a different locus, as they are in the human and mouse genomes. Immunohistochemical analysis showed the prominent expression of Lp3/Hapln3 in the smooth muscle tissues of the vascular wall and gastrointestinal tract. Further comparative studies revealed that Lp3/Hapln3 was well co-localized with versican around the smooth muscle cells of blood vessels but not around endothelial cells. In vitro experiments using primary cultured rat arterial smooth muscle cells (ASMCs) demonstrated the coordinated up-regulation of Lp3/Hapln3 and versican by platelet-derived growth factor (PDGF). These data were supported by in vivo studies of a mechanical vascular injury model in mice. Altogether, our results suggest that Lp3/Hapln3 is involved, together with versican and hyaluronan, in the formation of the pericellular matrix of vascular smooth muscle cells. 相似文献
74.
Noriko Oda Tetsuhiro Tsujino Toshitaka Tsuda Kazuhiro Yoshida Hirofumi Nakayama Wataru Yasui Eiichi Tahara 《Virchows Archiv. B, Cell pathology including molecular pathology》1989,58(1):273-277
The DNA ploidy pattern and amplification of ERBB and ERBB2 genes were examined in paraffinembedded tissue from gastric carcinomas
using flow cytometry and a slot-blot hybridization technique. The incidence of aneuploidy in well differentiated adenocarcinomas
(56%) was significantly higher (p<0.05) than that in poorly differentiated adenocarcinomas (21%). The DNA ploidy pattern was not remarkably different between the
primary tumors and metastatic deposits in lymph nodes. Of the nine specimens having an aneuploid stem cell line in the primary
tumor and/or in metastases, three showed ERBB2 gene amplification and one showed ERBB gene amplification. The incidence of
epidermal growth factor (EGF) immunoreactivity in tumor cells showed no difference between diploid and aneuploid tumors. These
findings indicate that aneuploidy is frequently associated with amplification of ERBB and ERBB2 genes. 相似文献
75.
Reproductive strategy and interspecific competition in the Lake-living gobiid fish isaza,Chaenogobius isaza 总被引:1,自引:0,他引:1
Isaza,Chaenogobius isaza, is a small gobiid fish endemic to Lake Biwa. It lives offshore throughout almost the entire year, showing a remarkable diel
vertical migration. In early spring, males and females migrate to lake shore to spawn under stones. Spawning season is limited
to a very short span of time in early spring, late April to early May. During this short spawning season, the male is supposed
to have only 2 brood cycles at maximum. At each brood cycle, the male is strictly monogynous, never accepting additional females.
Males therefore show a marked mate choice, choosing a larger female regardless of the size of the male himself. Females also
choose larger males. However, males are supposed to not waste time in male-male fighting in the natural spawning area. That
this very short spawning season and its occurrence in early spring is primarily to avoid interspecific competition with another
littorally reproducing goby Yoshinobori,Rhinogobius brunneus, is experimentally demonstrated. 相似文献
76.
Mating behaviour and associated songs were compared between 2 sympatric congeneric species,Nezara antennata andN. viridula, between which interspecific mating was known to occur under natural conditions. The fundamental sequence of mating behaviour
for these species was the same. Three kinds of songs were recorded from each sex ofN. antennata. ForN. viridula, 4 kinds of male songs and 3 kinds of female songs were recorded. The songs which corresponded with definite behavioural
bouts were distinct between these species. Some consideration was made as to why interspecific differences in the songs did
not sufficiently engender ethological isolation. In addition, some geographic variations in the songs were shown among Yugoslavian
(Čokl et al. 1972), American (Harris et al. 1982) and Japanese populations ofN. viridula. These variations were relatively inconspicuous when compared with the interspecific differences fromN. antennata. 相似文献
77.
Toshitaka Ikehara Hisao Yamaguchi Tetsuhiro Sakai Hiroshi Miyamoto 《生物化学与生物物理学报:生物膜》1984,775(3):297-307
On incubation of HeLa cells in chilled isotonic medium, intracellular Na+ (Nac+) increased and K+ (Kc+) decreased with time, reaching steady levels after 3 h. The steady levels varied in parallel with the extracellular cation concentrations ([Na+]e, [K+]e). The cell volumes and the protein and water contents, respectively, of cells kept for 3 h in chilled media of various [Na+]e and [K+]e were not significantly different. Ouabain-sensitive Rb+ influx took place at the initial rate for a certain period which depended on [Na+]c at the beginning of the assays. The existence of two external K+ loading sites per Na+/K+-pump was demonstrated. The affinities of the sites for Rb+ as a congener of K+ were almost the same. Nae+ inhibited ouabain-sensitive Rb+ influx competitively, whereas Kc+ was not inhibitory. Kinetic parameters were determined: the for Rbe+ in the absence of Nae+ was 0.16 mM and the Ki for Nae+ was 36.8 mM; the was 19.5 mM and the Ki for Kc+ seemed to be extremely large. The rate equation of the ouabain-sensitive Rb+ influx suggests that Na+ and K+ are exchanged alternately through the pump by a binary mechanism. 相似文献
78.
79.
Yosuke Suzuki Ayako Oda Jun Negami Daiki Toyama Ryota Tanaka Hiroyuki Ono Tadasuke Ando Toshitaka Shin Hiromitsu Mimata Hiroki Itoh Keiko Ohno 《Journal of lipid research》2022,63(3)
4β-Hydroxycholesterol (4β-OHC) is formed by Cytochrome P450 (CYP)3A and has drawn attention as an endogenous phenotyping probe for CYP3A activity. However, 4β-OHC is also increased by cholesterol autooxidation occurring in vitro due to dysregulated storage and in vivo by oxidative stress or inflammation, independent of CYP3A activity. 4α-hydroxycholesterol (4α-OHC), a stereoisomer of 4β-OHC, is also formed via autooxidation of cholesterol, not by CYP3A, and thus may have clinical potential in reflecting the state of cholesterol autooxidation. In this study, we establish a sensitive method for simultaneous quantification of 4β-OHC and 4α-OHC in human plasma using ultra-high performance liquid chromatography coupled to tandem mass spectrometry. Plasma samples were prepared by saponification, two-step liquid-liquid extraction, and derivatization using picolinic acid. Intense [M+H]+ signals for 4β-OHC and 4α-OHC di-picolinyl esters were monitored using electrospray ionization. The assay fulfilled the requirements of the US Food and Drug Administration guidance for bioanalytical method validation, with a lower limit of quantification of 0.5 ng/ml for both 4β-OHC and 4α-OHC. Apparent recovery rates from human plasma ranged from 88.2% to 101.5% for 4β-OHC, and 91.8% to 114.9% for 4α-OHC. Additionally, matrix effects varied between 86.2% and 117.6% for 4β-OHC and between 89.5% and 116.9% for 4α-OHC. Plasma 4β-OHC and 4α-OHC concentrations in healthy volunteers, stage 3–5 chronic kidney disease (CKD) patients, and stage 5D CKD patients as measured by the validated assay were within the calibration ranges in all samples. We propose this novel quantification method may contribute to accurate evaluation of in vivo CYP3A activity.Supplementary key words: cholesterol, cytochrome P450, kidney, kinetics, pharmacokinetics, 4β-hydroxycholesterol, 4α-hydroxycholesterol, cytochrome P450 3A, mass spectrometry, plasmaPharmacokinetics of drugs show large interindividual variability, and some drug-metabolizing enzymes and transporters are involved in the variability. Cytochrome P450 (CYP)3A is a major subfamily of metabolic enzymes involved in the metabolism of some drugs in the liver and small intestine (1). The main isoenzymes of this subfamily are CYP3A4 and CYP3A5. There is a large interindividual variability in CYP3A activity among patients, and the variability was reported to affect the clinical efficacy and the adverse reaction of CYP3A substrate drugs (2, 3). Thus, phenotyping of CYP3A activity is clinically important for more effective and safer treatment by CYP3A substrate drugs.Midazolam has been reported to be useful and considered a standard probe for CYP3A phenotyping (4, 5). Although midazolam is commonly used in drug-drug interaction studies (6, 7, 8, 9), this drug has some limitations in clinical application. For example, multiple blood samplings are needed to calculate the clearance for phenotyping, which limits its use in infants and elderly people. Midazolam shows high protein binding especially to albumin (approximately 96%) (10), and the free fraction may increase in patients with lower albumin levels, resulting in apparently increased hepatic clearance. Thus, phenotyping using midazolam may not be suitable in some patients with liver disease such as cirrhosis or kidney failure.To overcome these problems, 4β-hydroxycholesterol (4β-OHC) has drawn attention as an endogenous phenotyping probe for CYP3A activity. 4β-OHC is formed by CYP3A4 and CYP3A5 (11, 12) and has a long plasma half-life (approximately 17 days) (13). Since there is no circadian change in plasma 4β-OHC concentrations, one-point blood sampling is sufficient for CYP3A phenotyping. 4β-OHC is slowly metabolized by CYP7A1 (14), and CYP7A1 activity is not affected by kidney failure (15). Therefore, plasma 4β-OHC concentration is a suitable probe for CYP3A phenotyping in infants, elderly people, and patients with kidney failure or liver diseases including cirrhosis (16, 17, 18, 19, 20, 21).Several quantification methods have been reported for the measurement of plasma 4β-OHC concentrations using gas chromatography coupled to mass spectrometry (11) and high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) (22, 23, 24, 25, 26). Recently, Hautajärvi et al. (27) reported an ultra-high performance liquid chromatography coupled to high resolution mass spectrometry method for quantification of plasma 4β-OHC and 4α-hydroxycholesterol (4α-OHC) concentrations. 4α-OHC, a stereoisomer of 4β-OHC, is formed via autooxidation of cholesterol, and not by CYP3A. Therefore, plasma 4α-OHC concentration reflects plasma sample stability, because plasma 4α-OHC concentration increases in uncontrolled storage condition (28). Furthermore, oxysterols including 4β-OHC and 4α-OHC have been reported to be elevated by cholesterol autoxidation due to oxidative stress or inflammation in the liver, regardless of CYP3A activity (29). Thus, simultaneous quantification of 4β-OHC and 4α-OHC is preferred for phenotyping of CYP3A activity using clinical plasma samples.In this study, we established a sensitive method for simultaneous quantification of 4β-OHC and 4α-OHC in human plasma using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The method was applied to measure plasma 4β-OHC and 4α-OHC concentrations in healthy volunteers and patients with chronic kidney disease (CKD). 相似文献
80.
Noriyo Takeda Yoko Nakajima Osamu Koizumi Toshitaka Fujisawa Toshio Takahashi Midori Matsumoto Ryusaku Deguchi 《Molecular reproduction and development》2013,80(3):223-232
Oocyte maturation and subsequent spawning in hydrozoan jellyfish are generally triggered by light‐dark cycles. To examine if the initiation of the maturation process after light stimulus is mediated by neurotransmitters, neuropeptides isolated originally from Hydra magnipapillata were applied to sexually mature female medusae of the hydrozoan jellyfish Cytaeis uchidae. Among the Hydra neuropeptides tested, Hym‐53 (NPYPGLW‐NH2), as well as a nonphysiological peptide, CGLWamide (CGLW‐NH2), were most effective in inducing oocyte maturation and spawning. Hym‐355 (FPQSFLPRG‐NH2) also triggered these events, but the stimulatory effect was weaker. Since Hym‐53‐OH (NPYPGLW) and Hym‐355‐OH (FPQSFLPRG) had no effect, amidation at the C‐terminus may be critical for the stimulatory activities of the peptides. Exposure to Hym‐53 for 2 min was sufficient to trigger of oocyte maturation, and the spawned eggs were able to be fertilized and to develop normally. Transmission electron microscopy confirmed that bundles of axon‐like structures that contain dense‐core synaptic vesicles and microtubules are present in the ovarian ectodermal epithelium overlying the oocytes. In addition, immunohistological analyses revealed that some of the neurons in the ectodermal epithelium are GLWamide‐ and PRGamide‐positive. These results suggest that a neuropeptide signal transduction pathway is involved in mediating the induction of oocyte maturation and spawning in this jellyfish. Mol. Reprod. Dev. 80: 223–232, 2013. © 2013 Wiley Periodicals, Inc. 相似文献