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851.
Immunostimulation effect of jellyfish collagen 总被引:5,自引:0,他引:5
Sugahara T Ueno M Goto Y Shiraishi R Doi M Akiyama K Yamauchi S 《Bioscience, biotechnology, and biochemistry》2006,70(9):2131-2137
Certain edible large jellyfishes belonging to the order Rhizostomeae are consumed in large quantities in China and Japan. The exumbrella part of the edible jellyfish Stomolophus nomurai was cut and soaked in dilute hydrochloric acid solution (pH 3.0) for 12 h, and heated at 121 degrees C for 20 min. The immunostimulation effects of the jellyfish extract were examined. The jellyfish extract enhanced IgM production of human hybridoma HB4C5 cells 34-fold. IgM and IgG production of human peripheral blood lymphocytes (PBL) were also accelerated, 2.8- and 1.4-fold respectively. Moreover, production of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha by human PBL was stimulated 100- and 17-fold respectively. Collagenase treatment inactivated the immunostimulation activity of the jellyfish extract. In addition, purified collagen from bovine Achilles' tendon accelerated IgM production of hybridoma cells. These facts mean that collagen has an immunostimulation effect, and that the active substance in jellyfish extract is collagen. 相似文献
852.
Yamauchi S Sugahara T Nakashima Y Abe K Hayashi Y Akiyama K Kishida T Maruyama M 《Bioscience, biotechnology, and biochemistry》2006,70(12):2942-2947
The cytotoxic activity for colon 26 cell line of matairesinol, oxidized matairesinol, 9,9'-epoxylignan and oxidized 9,9'-epoxylignan were examined. (-)-Matairesinol (Mat 1) showed greatest cytotoxic activity (LC(50)=9 microg/ml) of the lactone-type lignans. 7,7'-Oxomatairesinol having same steric configuration as that of (-)-matairesinol showed greater activity (LC(50)=25 microg/ml) than hydroxy or mono-oxomatairesinol. The activities of 9,9'-epoxylignan and 7,7'-oxo-9,9'-epoxylignan having same steric configurations as (-)-matairesinol were weaker than that of corresponding matairesinols. Different activity levels were observed between enantiomers. 相似文献
853.
Assessing photosynthetic efficiency in an experimental mangrove canopy using remote sensing and chlorophyll fluorescence 总被引:2,自引:0,他引:2
Caroline J Nichol Uwe Rascher Shizue Matsubara Barry Osmond 《Trees - Structure and Function》2006,20(1):9-15
This study examined the ability of the photochemical reflectance index (PRI) to track changes in effective quantum yield (Δ
F/F
m
′), non-photochemical quenching (NPQ), and the xanthophyll cycle de-epoxidation (DPS) in an experimental mangrove canopy.
PRI was correlated with (Δ F/F
m
′) and NPQ over the 4-week measurement period and over the diurnal cycle. The normalised difference vegetation index (NDVI)
was not correlated with any aspect of photochemical efficiency measured using chlorophyll fluorescence or xanthophyll pigments.
This study demonstrated that photochemical adjustments were responsible for controlling the flow of energy through the photosynthetic
apparatus in this mangrove forest canopy rather than canopy structural or chlorophyll adjustments. 相似文献
854.
855.
Takao Suzuki Minoru Moriya Toshihiro Sakamoto Takuya Suga Hiroyuki Kishino Hidekazu Takahashi Makoto Ishikawa Keita Nagai Yumiko Imai Etsuko Sekino Masahiko Ito Hisashi Iwaasa Akane Ishihara Shigeru Tokita Akio Kanatani Nagaaki Sato Takehiro Fukami 《Bioorganic & medicinal chemistry letters》2009,19(11):3072-3077
Optimization of high-throughput screening hit 1a led to the identification of a novel spiro-piperidine class of melanin-concentrating hormone 1 receptor (MCH-1R) antagonists. Compound 3c was identified as a highly potent and selective MCH-1R antagonist, which has an IC50 value of 0.09 nM at hMCH-1R. The synthesis and structure–activity relationships of the novel spiro-piperidine MCH-1R antagonists are described. 相似文献
856.
Rika Tanaka Toshiyuki Owaki Sadahiro Kamiya Takuya Matsunaga Kazuya Shimoda Hiroaki Kodama Ryo Hayashi Takashi Abe Yosei P. Harada Motoyuki Shimonaka Hirofumi Yajima Hiroshi Terada Fumio Fukai 《The Journal of biological chemistry》2009,284(30):19817-19825
Fibronectin plays important roles in erythropoiesis through the fibronectin receptors VLA-4 and VLA-5. However, the substantial role of these fibronectin receptors and their functional assignment in erythroid differentiation are not yet fully understood. Here, we investigated the effects of cell adhesion to fibronectin on erythroid differentiation using K562 human erythroid progenitor cells. Erythroid differentiation could be induced in K562 cells in suspension by stimulating with hemin. This hemin-stimulated erythroid differentiation was highly accelerated when cells were induced to adhere to fibronectin by treatment with TNIIIA2, a peptide derived from tenascin-C, which has recently been found to induce β1-integrin activation. Another integrin activator, Mn2+, also accelerated hemin-stimulated erythroid differentiation. Adhesive interaction with fibronectin via VLA-4 as well as VLA-5 was responsible for acceleration of the hemin-stimulated erythroid differentiation in response to TNIIIA2, although K562 cells should have been lacking in VLA-4. Adhesion to fibronectin forced by TNIIIA2 causally induced VLA-4 expression in K562 cells, and this was blocked by the RGD peptide, an antagonist for VLA-5. The resulting adhesive interaction with fibronectin via VLA-4 strongly enhanced the hemin-stimulated activation of p38 mitogen-activated protein kinase, which was shown to serve as a signaling molecule crucial for erythroid differentiation. Suppression of VLA-4 expression by RNA interference abrogated acceleration of hemin-stimulated erythroid differentiation in response to TNIIIA2. Thus, VLA-4 and VLA-5 may contribute to erythropoiesis at different stages of erythroid differentiation.Hematopoietic stem and progenitor cells proliferate and differentiate in the bone marrow and fetal liver (1–6). Stromal cells of the bone marrow and fetal liver form a hematopoietic microenvironment called a “niche.” This microenvironment niche plays a crucial role in the regulation of the proliferation and differentiation of hematopoietic stem and progenitor cells. Besides humoral factors that include hematopoietic growth factors, adhesive interaction of hematopoietic stem and progenitor cells with stromal cells and/or the extracellular matrix (ECM)2 in the hematopoietic microenvironment is indispensable for hematopoietic development (1–6). The ECM in the hematopoietic microenvironment is composed of various macromolecules, such as fibronectin (FN), collagens, laminins, and proteoglycans. Among them, FN is one of the most important parts of the microenvironment niche (7–11). Also, in erythropoiesis, the importance of the adhesion of erythroid progenitors to FN via the FN receptors VLA-4 and VLA-5 has been reported (11–16). However, the substantial role of these FN receptors and their functional assignment in erythroid differentiation are not yet fully understood.We previously found that FN, which provides scaffolding for the adhesion of various cell types, has an alternative functional site opposing cell adhesion (17). A 22-mer peptide derived from the 14th FN type III-like (FNIII) repeat of the FN molecule, termed FNIII14, strongly suppresses cell adhesion to FN by inhibiting the activation of β1-integrins including VLA-4 and VLA-5 (18, 19). Conversely, we have recently found that tenascin (TN)-C, which is an anti-adhesive ECM protein (20, 21), has a functional site for stimulating cell adhesion to FN (22). A 22-mer peptide derived from the FNIII repeat A2 in the TN-C molecule, termed TNIIIA2, can induce the conformational change necessary for functional activation of FN receptors through binding with syndecan-4 (22, 23). The active sites of FNIII14 and TNIIIA2 appear to be cryptic in the molecular structures of FN and TN-C but are exposed by conformational change through interaction with other ECM molecules or by processing with matrix metalloproteinase-2 (22, 24). Thus, these functional sites found in FN and TN-C molecules, which act in opposition to their parental ECM proteins, may act as a negative feedback loop for preventing excessive cellular responses to these ECM proteins in biological processes with ECM rearrangement. In any case, FNIII14 and TNIIIA2 enable us to control, either negatively or positively, the adhesion of various cell types to FN.Various hematopoietic progenitor cell lines have been used in in vitro studies of hematopoietic differentiation. However, most hematopoietic progenitor cell lines are nonadherent, because their cell surface β1-integrins, including FN receptors, have impaired ligand-binding activity (25, 26). Therefore, in order to investigate the role of cell adhesion to FN in hematopoietic differentiation, their FN receptors must be activated. Since TNIIIA2 can induce activation of FN receptors in various hematopoietic progenitor cell lines (22), this peptide factor may be useful for investigating the substantial role of cell adhesion to FN in hematopoietic differentiation. Here, we investigate the effects of cell adhesion to FN on erythroid differentiation using TNIIIA2 and Mn2+ as the integrin activator and the human erythroid progenitor cell line K562, which only expresses VLA-5, as the FN receptor (27). As a result, we show that hemin-stimulated erythroid differentiation of K562 cells is strongly enhanced when K562 cells are forced to adhere to FN. Sustained adhesion to FN via VLA-5, which is induced by TNIIIA2 or Mn2+, causes induction of VLA-4 expression. The resulting adhesive interaction with FN via newly expressed VLA-4 then generates a conspicuous increase in the hemin-stimulated phosphorylation/activation of p38 MAP kinase, which is shown to serve as a signaling molecule crucial for erythroid differentiation of K562 cells. 相似文献
857.
We examined the prevalence of interactions between pairs of short chromosomal regions from one species (Solanum habrochaites) co-introgressed into a heterospecific genetic background (Solanum lycopersicum). Of 105 double introgression line (DIL) families generated from a complete diallele combination of 15 chromosomal segments, 39 (~38%) showed evidence for complex epistasis in the form of genotypic and/or allelic marker transmission distortion in DIL F2 populations. 相似文献
858.
859.
860.
As a first step in elucidating mechanisms of speciation in the Giliopsis group of Ipomopsis (Polemoniaceae), we examined patterns of morphological and genetic differentiation and crossability. This group comprises three species that diverged very recently: two perennials, I. guttata and I. tenuifolia, and one annual, I. effusa. Analysis of phenotypic variation established that the three species are distinct for floral characters, and this differentiation is maintained in a locality containing both perennial species. Next, we assessed the genealogical relationships with AFLPs. All sampled individuals of I. effusa clustered together, a result in accord with its genetic isolation. The perennials, which retain interfertility, were not resolved as sister taxa. Rather, individuals sampled from the single I. guttata population that is sympatric with I. tenuifolia were genetically more similar to I. tenuifolia samples than they were to conspecifics. This pattern may be due to substantial introgression of I. tenuifolia genomic regions that do not contribute to floral phenotype in I. guttata. Our result adds to mounting evidence that plant species, as defined by morphological characters, are often not genomically cohesive. Taken together, our data warrant caution in delimiting species with genetic markers alone, and, importantly, suggest that selection on species-diagnostic morphological characters can be sufficiently strong to counteract extensive gene flow. 相似文献