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781.
Role of nitric oxide in liver ischemia and reperfusion injury 总被引:5,自引:0,他引:5
Hines Ian N. Kawachi Shigeyuki Harada Hirohisa Pavlick Kevin P. Hoffman Jason M. Bharwani Sulaiman Wolf Robert E. Grisham Matthew B. 《Molecular and cellular biochemistry》2002,(1):229-237
The present study was designed to assess the role of endothelial cell and inducible nitric oxide synthase (eNOS, iNOS)-derived NO in ischemia/reperfusion (I/R)-induced pro-inflammatory cytokine expression and tissue injury in a murine model of hepatic I/R. Forty-five min of partial hepatic ischemia and 3 h of reperfusion resulted in a significant increase in liver injury as assessed by serum alanine aminotransferase and histopathology which occurred in the absence of neutrophil infiltration. Both iNOS and eNOS deficient mice exhibited enhanced liver injury when compared to their wild type (wt) controls again in the absence of neutrophil infiltration. Interestingly, message expression for both tumor necrosis factor-alpha (TNF-) and interleukin 12 (IL-12) were enhanced in eNOS, but not iNOS-deficient mice at 1 h post-ischemia when compared to their wt controls. In addition, eNOS message expression appeared to be up-regulated between 1 and 3 h of reperfusion in wt mice while iNOS deficient mice exhibited substantial increases at 1 but not 3 h. Taken together, these data demonstrate the ability of eNOS and iNOS to protect the post-ischemic liver, however their mechanisms of action may be very different. 相似文献
782.
Cytochrome c-mediated caspase-9 activation triggers apoptosis in Streptococcus pyogenes-infected epithelial cells 总被引:1,自引:1,他引:1
Ichiro Nakagawa Masanobu Nakata Shigetada Kawabata Shigeyuki Hamada 《Cellular microbiology》2001,3(6):395-405
Epithelial cells are the initial sites of host invasion by group A Streptococcus pyogenes (GAS), and their infection of epithelial cells has been suggested to induce apoptosis. However, the mechanism responsible for bacteria–host interaction and the induction of apoptosis has not been clearly understood. We demonstrate here that human pharyngeal epithelial HEp-2 cells became apoptotic with DNA fragmentation by invasion of GAS strains JRS4 (M6+ , F1+ ) and JRS145 (M6− , F1+ mutant of JRS4), whereas apoptotic cellular changes were not observed in SAM1 (M6+ , F1− mutant) or SAM2 (M6− , F1− mutant) infected HEp-2 cells. Confocal microscopy revealed that Bax translocation to mitochondria and cytochrome c release occurred after 4 h of infection. Western blot analyses showed that the amounts of Bcl-2 and Bcl-xL were decreased in the mitochondria of infected cells. In addition, we demonstrated that the release of nuclear histone from infected cells was prevented by the addition of caspase-9 inhibitor (Ac-LEHD-CHO). We conclude that the internalization of GAS in epithelial cells is necessary and sufficient for the induction of apoptosis, which is initiated by mitochondrial dysfunction, and the mechanism of GAS-induced apoptosis is clearly different from that induced by other intracellular invasive bacteria, e.g. Shigella and Salmonella species. 相似文献
783.
Orlofsky A Weiss LM Kawachi N Prystowsky MB 《Journal of immunology (Baltimore, Md. : 1950)》2002,168(4):1840-1846
A1 is an anti-apoptotic member of the Bcl-2 family that is up-regulated in inflammatory myeloid cells. In the present study, we investigated the role of A1 in the maintenance of acute inflammation in mice. Mice possess three genes encoding highly related isoforms of A1. A1-a isoform mRNA was minimally expressed in resident peritoneal macrophages, but was present at a 300-fold higher level in inflammatory macrophages elicited by i.p. infection with Toxoplasma gondii. In comparison, A1-b and A1-d levels were 3- and 10-fold higher, respectively. Peritoneal leukocytosis was decreased in infected A1-a-deficient mice compared with wild-type, and this reduction was associated with a small but reproducible enhancement of survival. These effects could not be explained by an alteration in peritoneal parasite load, nor by increased apoptosis of infected inflammatory cells, which were protected from cell death by an A1-a-independent mechanism. Increased apoptosis in inflammatory neutrophils was observed sporadically in A1-a-deficient mice. Regulation of apoptosis by A1-a may be an important proinflammatory event in acute host responses. 相似文献
784.
Q. Hu N. Kurano M. Kawachi I. Iwasaki S. Miyachi 《Applied microbiology and biotechnology》1998,49(6):655-662
To test the feasibility of CO2 remediation by microalgal photosynthesis, a modified type of flat-plate photobioreactor [Hu et al. (1996) Biotechnol Bioeng 51:51–60] has been designed for cultivation of a high-CO2-tolerant unicellular green alga Chlorococcum littorale. The modified reactor has a narrow light path in which intensive turbulent flow is provided by streaming compressed air through
perforated tubing into the culture suspension. The length of the reactor light path was optimized for the productivity of
biomass. The interrelationship between cell density and productivity, as affected by incident light intensity, was quantitatively
assessed. Cellular ultrastructural and biochemical changes in response to ultrahigh cell density were investigated. The potential
of biomass production under extremely high CO2 concentrations was also evaluated. By growing C. littorale cells in this reactor, a CO2 fixation rate of 16.7 g CO2 l−1 24 h−1 (or 200.4 g CO2 m−2 24 h−1) could readily be sustained at a light intensity of 2000 μmol m−2 s−1 at 25 °C, and an ultrahigh cell density of well over 80 g l−1 could be maintained by daily replacing the culture medium.
Received: 20 October 1997 / Received revision: 19 December 1997 / Accepted: 24 January 1998 相似文献
785.
786.
Saburo Sone Masanobu Munekata Makoto Tanaka Teruhiro Utsugi Takeshi Ogura 《Biotherapy》1989,1(3):233-243
Human blood monocytes activated to the tumoricidal state were previously found to release a factor(s) responsible for tumor cell killing. The activity of the tumor cytotoxic factor(s) (TCF) was determined by release assay of radioactivity from human A375 melanoma cells. On fractionation of the supernatant of activated monocytes by Ultrogel AcA34 and TSK-G3000SW gel chromatographies two major peaks of the material with TCF activity with MWs of 30,000 and 15,000, called TCF-I and TCF-11, respectively were obtained. TCF-II could be neutralized by polyclonal anti-IL-1 antiserum, but anti-IL-1 antiserum did not neutralize either factor. TCF-I was separated by ampholine column electrofocusing into three major fractions with TCF activity at pI 5, 6 and 6.8, named TCF-1, TCF-1 and TCF-1, respectively. The cytotoxic and IL-1 activities of TCF-1 were neutralized by anti-IL-1 serum, whereas those of TCF-1 and TCF-1 were not completely neutralized by anti-IL-1 or anti-IL-1 antiserum. On DEAE ion-exchange chromatography (TSK DEAE 5PW) TCF-I gave two peaks with TCF activity (TCF-I1 and TCF-I2). TCF-I1 was slightly neutralized by anti-TNF antibody, but TCF-I2 was not affected by antisera against IL-1 and IL-1, or anti-TNF antibody, thus ruling out the possibility that tumor necrosis factor (TNF) might be involved in tumor cell killing mediated by TCF-I2. These results indicate that human monocyte-mediated cytotoxicity against human A375 melanoma cells is mediated in part by a tumor cytotoxic factor (TCF; MW, 30,000; pI 6), differing from IL-1 and TNF. 相似文献
787.
Arabidopsis thaliana AtMTP1 belongs to the cation diffusion facilitator family and is localized on the vacuolar membrane. We investigated the enzymatic kinetics of AtMTP1 by a heterologous expression system in the yeast Saccharomyces cerevisiae, which lacked genes for vacuolar membrane zinc transporters ZRC1 and COT1. The yeast mutant expressing AtMTP1 heterologously was tolerant to 10 mm ZnCl(2). Active transport of zinc into vacuoles of living yeast cells expressing AtMTP1 was confirmed by the fluorescent zinc indicator FuraZin-1. Zinc transport was quantitatively analyzed by using vacuolar membrane vesicles prepared from AtMTP1-expressing yeast cells and radioisotope (65)Zn(2+). Active zinc uptake depended on a pH gradient generated by endogenous vacuolar H(+)-ATPase. The activity was inhibited by bafilomycin A(1), an inhibitor of the H(+)-ATPase. The K(m) for Zn(2+) and V(max) of AtMTP1 were determined to be 0.30 microm and 1.22 nmol/min/mg, respectively. We prepared a mutant AtMTP1 that lacked the major part (32 residues from 185 to 216) of a long histidine-rich hydrophilic loop in the central part of AtMTP1. Yeast cells expressing the mutant became hyperresistant to high concentrations of Zn(2+) and resistant to Co(2+). The K(m) and V(max) values were increased 2-11-fold. These results indicate that AtMTP1 functions as a Zn(2+)/H(+) antiporter in vacuoles and that a histidine-rich region is not essential for zinc transport. We propose that a histidine-rich loop functions as a buffering pocket of Zn(2+) and a sensor of the zinc level at the cytoplasmic surface. This loop may be involved in the maintenance of the level of cytoplasmic Zn(2+). 相似文献
788.
Akiyoshi Yamada Daisei Kitamura Masanobu Setoguchi Yosuke Matsuda Yasushi Hashimoto Norihisa Matsushita Masaki Fukuda 《Ecological Research》2008,23(6):983-993
Monotropastrum humile is nearly lacking in chlorophyll and obtains its nutrients, including carbon sources, from associated mycorrhizal fungi.
We analyzed the mycorrhizal fungal affinity and species diversity of M. humile var. humile mycorrhizae to clarify how the plant population survives in Japanese forest ecosystems. We classified 78 samples of adult
M. humile var. humile individuals from Hokkaido, Honshu, and Kyusyu Islands into 37 root mycorrhizal morphotypes. Of these, we identified 24 types
as Russula or Lactarius fungal taxa in the Russulaceae, Basidiomycetes, but we could not identify the remaining 13 types as to their genus in the
Basidiomycetes. The number of fungal species on M. humile var. humile was the highest in the plant subfamily. The diversity of fungal species revealed its increased trends in natural forests
at the stand level, fagaceous vegetation, and cool-temperate climate. The most frequently observed fungus colonized mainly
samples collected from sub-alpine forests; the second most frequently observed fungus colonized samples collected from sub-alpine
to warm-temperate forests. These results suggest that Japanese M. humile populations are associated with specific but diverse fungi that are common ectomycorrhizal symbionts of various forest canopy
trees, indicating a tripartite mycorrhizal relationship in the forest ecosystem. 相似文献
789.
790.
Hideo Etoh Kazuo Ina Masanobu Iguchi 《Bioscience, biotechnology, and biochemistry》2013,77(12):2999-3000
1-Isobutyl-5-(4-phenoxyphenyl)imidazole (KK-98), an inhibitor of juvenile hormone (JH) biosynthesis in the cockroach, and related imidazole compounds were evaluated against silkworm, Bombyx mori, for their activity to induce precocious metamorphosis. KK-98 induced precocious metamorphosis in the 4th instar larvae at high doses. Replacement of the 4-phenoxy group by a 3-phenoxy or 3-benzyloxy group on the benzene ring increased the activity. Among this series of compounds, 5-(3-benzyloxyphenyl)-1-isopropylimidazole (8) showed the highest activity. The induction of precocious metamorphosis by compound 8 was rescued by the simultaneous application of methoprene, a JH minie. When newly molted 3rd instar larvae were treated with a high dose of compound 8, a few larvae formed larval-pupal intermediates in the 3rd instar stage, which has not been formed by treating of any other imidazoles so far. 相似文献