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51.
Inactivation of the vascular permeability-increasing activity of bradykinin by mycoplasmas 总被引:1,自引:0,他引:1
Mycoplasma pneumoniae, M. genitalium, M. fermentans, M. hominis, M. salivarium, M. orale, Ureaplasma urealyticum and Acholeplasma laidlawii inactivated the vascular permeability-increasing activity of bradykinin when the mixture of bradykinin and mycoplasma cells was injected after incubation at 37 degrees C for 1 h. Cell components responsible for inactivation of the activity of bradykinin were found to be arginine-specific aminopeptidase and carboxypeptidase. 相似文献
52.
Takeshi Mikami Tsuguo Horikawa Tomonori Murakami Tatsuji Matsumoto Akiko Yamakawa Shoko Murayama Susumi Katagiri Kunihiro Shinagawa Masuko Suzuki 《FEMS microbiology letters》1994,119(1-2):53-57
Abstract We developed an improved HEp-2 cell assay method for the detection of Bacillus cereus toxin, which affects the proliferation of HEp-2 cells. The cytostatic toxin was stable upon exposure to heat, pH 2, pH 11 and trypsin, which suggests it is an emetic. Using the HEp-2 cell assay, we examined the distribution and contamination of B. cereus strains that produced an emetic toxin in various foods. Although there were 228 enterotoxin producers among 310 B. cereus strains obtained from foods, 16 of them produced the cytostatic type (emetic toxin). All of the strains that produced the cytostatic toxin were of the H.1 serotype. 相似文献
53.
Norikuni Kumano Dai Haraguchi & Tsuguo Kohama 《Entomologia Experimentalis et Applicata》2009,131(1):39-45
Because multiple mating by females encourages sperm competition, the assessment of female mating status before insemination is important for males in order to avoid the risk of sperm competition or to intensify sperm competition. When interacting with females before sperm transfer, males can alter their mating tactics according to the risk or intensity of sperm competition. Information on how mating systems are associated with sperm competition is essential for sterile insect technique eradication programs, which depend on successful mating of released sterile males with wild females. We tested whether males of the West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae), adjusted their mating behavior in response to female mating experience and/or age. As virgin/young female weevils accepted males more easily than non-virgin/old females, assessing females before insemination can be adaptive for male weevils. We found that E. postfasciatus males were unable to adjust their mating tactics in response to female mating status. Although this mating strategy would be costly for individual male weevils, the ability in males to discriminate female mating status can prevent the chance of mating with already-mated females containing the sperm of wild male(s). Therefore, the mating tactics of male E. postfasciatus are advantageous for sterile insect technique eradication programs. 相似文献
54.
Sugiyama D Kulkeaw K Mizuochi C Horio Y Okayama S 《Biochemical and biophysical research communications》2011,(2):1770-306
In mammals, definitive erythropoiesis first occurs in fetal liver (FL), although little is known about how the process is regulated. FL consists of hepatoblasts, sinusoid endothelial cells and hematopoietic cells. To determine niche cells for fetal liver erythropoiesis, we isolated each FL component by flow cytometry. mRNA analysis suggested that Dlk-1-expressing hepatoblasts primarily expressed EPO and SCF, genes encoding erythropoietic cytokines. EPO protein was detected predominantly in hepatoblasts, as assessed by ELISA and immunohistochemistry, and was not detected in sinusoid endothelial cells and hematopoietic cells. To characterize hepatoblast function in FL, we analyzed Map2k4−/− mouse embryos, which lack hepatoblasts, and observed down-regulation of EPO and SCF expression in FL relative to wild-type mice. Our observations demonstrate that hepatoblasts comprise a niche for erythropoiesis through cytokine secretion. 相似文献
55.
56.
Analysis of 265 plants derived from 13 sites in the Rokko Mountains shows that the widely distributed eastern AsianEupatorium chinense var.simplicifolium consists of seven cytotypes. These polymorphic karyotypes comprise four levels of ploidy based on X=10 and partial deficiency,
occurring either alone or in combination. The polyploid cytotypes exhibit anomalous meiosis and highly variable pollen stainability
in contrast to the nearly-normal behaviour of the diploid. The polyploid cytotypes were revealed as being agamospermous. They
are readily distinguishable from the diploid cytotypes by several morphological characters and by growth habits closely related
to their respective niches. Two or more cytotypes occurred in all sites examined, the most common being the coexistence of
triploid and tetraploid cytotypes. The frequencies of occurrence of the pentaploid plants and the cytotypes involving a deficient
chromosome were relatively low. While the diploid cytotype is restricted to fragile gravitational slopes and rocky areas which
are poor in species and lack tall competitors, the polyploids occur widely in the grasslands, the roadsides or the forest-margins,
closely associated with tall grasses and forbs such asMiscanthus sinensis. Based on these data, theE. chinense var.simplicifolium complex is divided into two distinct groups: the diploid cytotype and the polyploid cytotypes. 相似文献
57.
T Tsuchida M Takemura J H Qian Y Izumi T Mizuochi R Maekawa H Fujiwara T Hamaoka 《Microbiology and immunology》1986,30(1):65-74
Contact sensitivity to trinitrophenyl (TNP) hapten was induced by subcutaneous (s.c.) administration of TNP-modified syngeneic spleen cells or epidermal cells (EC) (TNP-EC). Intraperitoneal (i.p.) inoculation of TNP-EC resulted in a comparable response, whereas i.p. administration of TNP-spleen cells or TNP-modified-ultraviolet (UV)-preirradiated EC (TNP-UV-EC) failed to induce TNP-contact sensitivity responses. The present study investigates the effect of UV-irradiation on the potential of EC for inducing the contact sensitivity response. Exposure of BALB/c mouse EC in vitro to 1600 J/m2 of UV-B before they were modified with TNP had no discernible effect on the Ia-positivity and viability of EC. Coexistence of TNP-UV-EC had no inhibitory effect upon the contact sensitivity response induced by TNP-EC via the i.p. route. The absence of suppressor cell generation was substantiated by the adoptive transfer of spleen cells from mice administered TNP-UV-EC i.p. to normal syngeneic mice. The effect of interleukin 1 (IL-1) or epidermal cell-derived thymocyte-activating factor (ETAF) in restoring the ability of TNP-UV-EC to induce contact sensitivity was examined. IL-1 or ETAF administered along with TNP-spleen cells i.p. induced a potent contact sensitivity response, whereas the same preparations of IL-1 or ETAF were unable to restore the contact sensitivity induction by TNP-UV-EC. The results are discussed in the context of UV-induced cell surface changes of the Langerhans cell population. 相似文献
58.
A non-penetrating probe, 2,4,6-trinitrobenzenesulfonate, inhibited the activity of the carboxypeptidase purified from the cell membranes of Mycoplasma salivarium and the same enzymatic activity of intact Mycoplasma cells as well. Growth of the organism in medium containing benzoylglycyl-L-arginine resulted in a higher pH and higher turbidity than growth in the same medium without this supplement. It was concluded that the enzyme existed in the outer surface of the membrane of the cells and probably functioned to supply the organism with arginine as an energy source. 相似文献
59.
Sowi Sekiya Yoshimi Tomita Hour-Young Chen Makoto Kawata Tatsuya Oosaki Tsuguo Kuwata Hiroyoshi Takamizawa 《Differentiation; research in biological diversity》1987,33(3):266-269
We examined the sensitivity of four human germ-cell-tumor cell lines exhibiting different stages of differentiation to human interferons (IFNs) in vitro. The cell lines were derived from two embryonal carcinomas (NEC 8 and NEC 14), a choriocarcinoma (IMa), and a yolk-sac tumor (HUOT). Treatment with poly I:C induced IFN production in IMa and HUOT cells, but not in NEC-8 and NEC-14 cells. In the two embryonal-carcinoma cell lines, the addition of IFN-alpha, IFN-beta, and IFN-gamma did not prevent infection by vesicular stomatitis virus and encephalomyocarditis virus. Also, in these two lines, 2-5A synthetase was not induced by the addition of IFN-alpha. In contrast, both IMa and HUOT showed sensitivity to the antiviral action of IFN-alpha and IFN-beta against the two viruses, and 2-5A synthetase was induced by IFN-alpha. IFNs added at doses of up to 1000 IU/ml had no antiproliferative effect on NEC 8, NEC 14, and HUOT, whereas colony formation by IMa cells was greatly suppressed by all three forms of IFN. These results indicate that the production of and sensitivity to IFN are developmentally regulated and are related to the level of differentiation of human germ-cell stem cells. 相似文献
60.