全文获取类型
收费全文 | 405篇 |
免费 | 36篇 |
出版年
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 8篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 2篇 |
2016年 | 9篇 |
2015年 | 20篇 |
2014年 | 10篇 |
2013年 | 16篇 |
2012年 | 24篇 |
2011年 | 21篇 |
2010年 | 14篇 |
2009年 | 16篇 |
2008年 | 22篇 |
2007年 | 15篇 |
2006年 | 18篇 |
2005年 | 18篇 |
2004年 | 23篇 |
2003年 | 29篇 |
2002年 | 15篇 |
2001年 | 16篇 |
2000年 | 18篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有441条查询结果,搜索用时 406 毫秒
101.
Ichiro Tamaki Katsushige Nomura Reiko Nomura Chieko Tate Chikara Watanabe Yoshihiro Miyakami Yumiko Yabe 《Landscape and Ecological Engineering》2018,14(2):269-276
Magnolia stellata is a rare subcanopy tree species that grows in secondary forests in warm temperate zones. It is now endangered due to habitat degradation by vegetation succession. In an attempt to improve the habitat, a 30 m?×?10 m plot (0.03 ha) was set up with all vegetation including M. stellata being clear-cut in January 2012. The number of sprouts increased for 1–2 years after clear-cutting and then gradually decreased or remained constant. Five years after clear-cutting, the numbers of individuals and stems, and the total basal area (BA), were 87.0, 165.5 and 3.2%, respectively, of the values before clear-cutting. BA was highest for Ilex pedunculosa, followed by M. stellata and Hydrangea paniculata. Some sprouted individuals of M. stellata produced flower buds in the second year after clear-cutting, and flowered and fruited in the spring and summer of the third year, respectively. The densities of potential canopy species were 18,533 ha?1 (height >?0.5 m) and 7,267 ha?1 (height >?1.2 m), vastly exceeding the value of the criterion for successful natural regeneration after clear-cutting of warm temperate forests in the region (3,000 ha?1). Based on this criterion, it is thus considered that the natural regeneration has reached completion. However, 45.1% (height >?0.5 m) and 95.5% (height >?1.2 m) of M. stellata individuals were regenerated by sprouting. Further research is needed into how individuals, regenerated from seedlings, develop and reach sexual maturity, and how successive generations change. 相似文献
102.
HKR1 encodes a cell surface protein that regulates both cell wall beta-glucan synthesis and budding pattern in the yeast Saccharomyces cerevisiae. 总被引:3,自引:1,他引:2 下载免费PDF全文
T Yabe T Yamada-Okabe S Kasahara Y Furuichi T Nakajima E Ichishima M Arisawa H Yamada-Okabe 《Journal of bacteriology》1996,178(2):477-483
We previously isolated the Saccharomyces cerevisiae HKR1 gene that confers on S. cerevisiae cells resistance to HM-1 killer toxin secreted by Hansenula mrakii (S. Kasahara, H. Yamada, T. Mio, Y. Shiratori, C. Miyamoto, T. Yabe, T. Nakajima, E. Ichishima, and Y. Furuichi, J. Bacteriol. 176:1488-1499, 1994). HKR1 encodes a type 1 membrane protein that contains a calcium-binding consensus sequence (EF hand motif) in the cytoplasmic domain. Although the null mutation of HKR1 is lethal, disruption of the 3' part of the coding region, which would result in deletion of the cytoplasmic domain of Hkr1p, did not affect the viability of yeast cells. This partial disruption of HKR1 significantly reduced beta-1,3-glucan synthase activity and the amount of beta-1,3-glucan in the cell wall and altered the axial budding pattern of haploid cells. Neither chitin synthase activity nor chitin content was significantly affected in the cells harboring the partially disrupted HKR1 allele. Immunofluorescence microscopy with an antibody raised against Hkr1p expressed in Escherichia coli revealed that Hkr1p was predominantly localized on the cell surface. The cell surface localization of Hkr1p required the N-terminal signal sequence because the C-terminal half of Hkr1p was detected uniformly in the cells. These results demonstrate that HKR1 encodes a cell surface protein that regulates both cell wall beta-glucan synthesis and budding pattern and suggest that bud site assembly is somehow related to beta-glucan synthesis in S. cerevisiae. 相似文献
103.
A new species of sculpin,Icelus ecornis (Scorpaeniformes: Cottidae) from the southwestern Okhotsk Sea 总被引:1,自引:1,他引:0
A new cottid species,Icelus ecornis, is described on the basis of 31 specimens collected from 159–226 m in the southwestern Okhotsk Sea off Hokkaido, Japan.
It is distinguished from all other members of the genusIcelus by the following combination of characters: no supraocular and parietal spines; short blunt nuchal spine; cirri absent from
head and body, except for supraocular, parietal and nuchal regions; platelike scales of dorsal row bearing 6–10 long uniform
spinules; tubular lateral line scales bearing small spines on dorsal and posterior margins; large oval black spot on first
dorsal fin; 16–20 anal fin rays. 相似文献
104.
Juvenile development ofSuggrundus meerdervoortii was described, based on twelve specimens (12.9–43.8 mm SL) collected from off Yamagata Prefecture, Japan Sea. Two exterior
openings in the lateral line scales were completed at ca. 35 mm SL, with the interopercular flap and iris lappet being visible
at ca. 44 mm SL, these all being useful taxonomic characters. In juveniles and additional young and adult specimens (ca. 70–191
mm SL), the proportions of head length, snout length, orbital diameter, caudal peduncle depth and caudal fin length decreased
with growth; interorbital width decreased rapidly until ca. 70 mm SL, but more or less stabilised thereafter (70–191 mm SL). 相似文献
105.
Comprehensive analysis of motions in molecular dynamics trajectories of the actin capping protein and its inhibitor complexes 下载免费PDF全文
The actin capping protein (CP) binds to actin filaments to block further elongation. The capping activity is inhibited by proteins V‐1 and CARMIL interacting with CP via steric and allosteric mechanisms, respectively. The crystal structures of free CP, CP/V‐1, and CP/CARMIL complexes suggest that the binding of CARMIL alters the flexibility of CP rather than the overall structure of CP, and this is an allosteric inhibition mechanism. Here, we performed molecular dynamics (MD) simulations of CP in the free form, and in complex with CARMIL or V‐1. The resulting trajectories were analyzed exhaustively using Motion Tree, which identifies various rigid‐body motions ranging from small local motions to large domain motions. After enumerating all the motions, CP flexibilities with different ligands were characterized by a list of frequencies for 20 dominant rigid‐body motions, some of which were not identified in previous studies. The comparative analysis highlights the influence of the binding of the CARMIL peptide to CP flexibility. In free CP and the CP/V‐1 complex, domain motions around a large crevice between the N‐stalk and the CP‐S domain occur frequently. The CARMIL peptide binds the crevice and suppresses the motions effectively. In addition, the binding of the CARMIL peptide enhances and alters local motions around the pocket that participates in V‐1 binding. These newly identified motions are likely to suppress the binding of V‐1 to CP. The observed changes in CP motion provide insights that describe the mechanism of allosteric regulation by CARMIL through modulating CP flexibility. Proteins 2016; 84:948–956. © 2016 Wiley Periodicals, Inc. 相似文献
106.
Ryotaro Matsui Kazuhiro Takagi Futa Sakakibara Tomoko Abe Kiwamu Shiiba 《Biodegradation》2016,27(2-3):155-163
To determine the concentration of soluble 1,4-dioxane during biodegradation, a new method using of high-performance liquid chromatography equipped with a hydrophilic interaction chromatography column was developed. The developed method enabled easy and rapid determination of 1,4-dioxane, even in saline medium. Microbes capable of degrading 1,4-dioxane were selected from the seawater samples by the seawater-charcoal perfusion apparatus. Among 32 candidate 1,4-dioxane degraders,, strain RM-31 exhibited the strongest 1,4-dioxane degradation ability. 16S rDNA sequencing and the similarity analysis of strain RM-31 suggested that this organism was most closely related to Pseudonocardia carboxydivorans. This species is similar to Pseudonocardia dioxanivorans, which has previously been reported as a 1,4-dioxane degrader. Strain RM-31 could degrade 300 mg/L within 2 days. As culture incubation times increasing, the residual 1,4-dioxane concentration was decreasing and the total protein contents extracted from growth cells were increasing. The optimum initial pH of the broth medium and incubation temperature for 1,4-dioxane degradation were pH 6–8 and 25 °C. The biodegradation rate of 1,4-dioxane by strain RM-31 at 25 °C in broth medium with 3 % NaCl was almost 20 % faster than that without NaCl. It was probably a first bacteria from the seawater that can exert a strong degrading ability. 相似文献
107.
Mayu Morita Yuiko Sato Ryotaro Iwasaki Tami Kobayashi Ryuichi Watanabe Takatsugu Oike Kana Miyamoto Yoshiaki Toyama Morio Matsumoto Masaya Nakamura Hiromasa Kawana Taneaki Nakagawa Takeshi Miyamoto 《PloS one》2016,11(11)
Anti-bone resorptive drugs such as bisphosphonates, the anti-RANKL antibody (denosumab), or selective estrogen receptor modulators (SERMs) have been developed to treat osteoporosis. Mechanisms underlying activity of bisphosphonates or denosumab in this context are understood, while it is less clear how SERMs like tamoxifen, raloxifene, or bazedoxifene inhibit bone resorption. Recently, accumulation of hypoxia inducible factor 1 alpha (Hif1α) in osteoclasts was shown to be suppressed by estrogen in normal cells. In addition, osteoclast activation and decreased bone mass seen in estrogen-deficient conditions was found to require Hif1α. Here, we used western blot analysis of cultured osteoclast precursor cells to show that tamoxifen, raloxifene, or bazedoxifene all suppress Hif1α protein accumulation. The effects of each SERM on osteoclast differentiation differed in vitro. Our results suggest that interventions such as the SERMs evaluated here could be useful to inhibit Hif1α and osteoclast activity under estrogen-deficient conditions. 相似文献
108.
Subgroups of type A blood, named A1, A2, and A1-A2 intermediate (Aint), are specifically characterized by their peculiar A alleles and have their own A1-, A2- or Aint-forms of alpha-N-acetyl-D-galactosaminyltransferase (A-transferase). It is known, however, that certain type A2B persons exhibit A1-transferase. The reason may be an unusual alpha-galactosyltransferase (B-transferase). This strong B-transferase competes with A-transferase for the substrate, H antigen, so as to decrease the A and H antigens on the red cells. We studied this blood group over three generations and found that the strong B-transferase is, in fact, inherited with the B gene and is dominant over normal B-transferase. In AB blood groups in Tokyo, the frequency of people with a strong B-transferase is 5% for A1B and 22% for A2B. This enzyme does not always cause weak H or A antigens. 相似文献
109.
M Tani K Mizuno S Hashimoto N Kunii S Niimura R Yabe H Watari S Fukuchi 《Life sciences》1986,38(25):2277-2284
High activity of angiotensin-converting enzyme was demonstrated in human pituitary tissue. This activity required the presence of chloride ion and was almost completely inhibited by a specific converting enzyme inhibitor captopril (10 nM), indicating that the activity measured is indeed angiotensin-converting enzyme. The specific activity of the enzyme was 1.68 +/- 1.20 nmol hippuric acid generated mg of protein-1 min-1 (mean +/- SD, for 11 specimens). The biochemical features of the enzyme were closely related to the well-characterized human lung converting enzyme, such as molecular weight (290,000), optimum pH (8.0-8.5), the presence of glycoprotein residues, and dependence on chloride ion concentration. These results provide definitive evidence for the presence of angiotensin-converting enzyme in human pituitary tissue. 相似文献
110.
Ryotaro Yoshida Yoshihiro Urade Koh Nakata Yasuyoshi Watanabe Osamu Hayaishi 《Archives of biochemistry and biophysics》1981,212(2):629-637
Indoleamine 2,3-dioxygenase activity in the supernatant fractions (30,000g, 30 min) from various tissues of mice increased almost linearly after a single intraperitoneal administration of bacterial lipopolysaccharide (5 to 20 μg/mouse). The most prominent effect was observed in the lung, where both specific and total enzyme activities increased 40 to 80-fold during the first 24 h. Significant (10- to 20-fold) stimulation was also observed in the seminal vesicle, coagulating gland, colon, and caecum, and severalfold in the trachea, stomach, heart, small intestine, and spleen. Lipid A fraction, the biologically active unit in the lipopolysaccharide complex, was as active as the lipopolysaccharide preparations from either Escherichia coli or Salmonella S and R mutant strains, whereas the polysaccharide fraction was inactive under identical experimental conditions. When mice were pretreated with a series of daily injections of bacterial lipopolysaccharide, enzyme induction was no longer evident, indicating that tolerance to this agent had developed and that enzyme induction was caused by lipopolysaccharide but not by possible contaminants in the preparations. The enzyme activities from normal and lipopolysaccharide-treated mice were exclusively found in the soluble fractions of mouse lung homogenates. Other enzyme activities in the lung such as lysosomal (acid phosphatase), microsomal (prostaglandin cyclooxygenase), mitochondrial (monoamine oxidase and superoxide dismutase), and soluble enzyme activities (lipooxygenase and superoxide dismutase) were not significantly altered by this treatment. This increase in the enzyme activity with the lipopolysaccharide treatment was abolished with a simultaneous administration of cycloheximide or actinomycin D, and an immunological analysis with antibody for mouse enzyme (rabbit IgG) demonstrated that the observed increment of the enzyme activity was essentially due to an increase in the enzyme protein. 相似文献