全文获取类型
收费全文 | 5636篇 |
免费 | 395篇 |
出版年
2021年 | 48篇 |
2019年 | 55篇 |
2018年 | 58篇 |
2017年 | 59篇 |
2016年 | 83篇 |
2015年 | 101篇 |
2014年 | 128篇 |
2013年 | 308篇 |
2012年 | 267篇 |
2011年 | 192篇 |
2010年 | 143篇 |
2009年 | 122篇 |
2008年 | 237篇 |
2007年 | 236篇 |
2006年 | 249篇 |
2005年 | 212篇 |
2004年 | 248篇 |
2003年 | 248篇 |
2002年 | 259篇 |
2001年 | 234篇 |
2000年 | 217篇 |
1999年 | 182篇 |
1998年 | 68篇 |
1997年 | 60篇 |
1996年 | 47篇 |
1995年 | 40篇 |
1994年 | 54篇 |
1993年 | 53篇 |
1992年 | 138篇 |
1991年 | 113篇 |
1990年 | 137篇 |
1989年 | 140篇 |
1988年 | 114篇 |
1987年 | 105篇 |
1986年 | 98篇 |
1985年 | 84篇 |
1984年 | 79篇 |
1983年 | 62篇 |
1982年 | 50篇 |
1981年 | 46篇 |
1980年 | 38篇 |
1979年 | 73篇 |
1978年 | 54篇 |
1977年 | 48篇 |
1976年 | 36篇 |
1975年 | 41篇 |
1974年 | 42篇 |
1973年 | 38篇 |
1972年 | 45篇 |
1970年 | 33篇 |
排序方式: 共有6031条查询结果,搜索用时 15 毫秒
321.
Masakazu Atobe Kenji Naganuma Masashi Kawanishi Akifumi Morimoto Ken-ichi Kasahara Shigeki Ohashi Hiroko Suzuki Takahiko Hayashi Shiro Miyoshi 《Bioorganic & medicinal chemistry letters》2013,23(22):6064-6067
We describe a medicinal chemistry approach to generate a series of 2-(1H-pyrazol-1-yl)thiazole compounds that act as selective EP1 receptor antagonists. The obtained results suggest that compound 12 provides the best EP1 receptor antagonist activity and demonstrates good oral pharmacokinetics. 相似文献
322.
Yuusuke Tamura Kyouhei Hayashi Naoki Omori Yuji Nishiura Kana Watanabe Nobuyuki Tanaka Masahiko Fujioka Naoki Kouyama Akira Yukimasa Yukari Tanaka Takeshi Chiba Hideki Tanioka Hirohide Nambu Hideo Yukioka Hiroki Sato Takayuki Okuno 《Bioorganic & medicinal chemistry letters》2013,23(1):90-95
Optimization of HTS hit 1 for NPY Y5 receptor binding affinity, CYP450 inhibition, solubility and metabolic stability led to the identification of some orally available oxygen-linker derivatives for in vivo study. Among them, derivative 4i inhibited food intake induced by the NPY Y5 selective agonist, and chronic oral administration of 4i in DIO mice caused a dose-dependent reduction of body weight gain. 相似文献
323.
H. Ohsaki T. Hirouchi N. Hayashi E. Okanoue M. Ohara N. Kuroda E. Hirakawa Y. Norimatsu 《Cytopathology》2013,24(1):52-57
H. Ohsaki, T. Hirouchi, N. Hayashi, E. Okanoue, M. Ohara, N. Kuroda, E. Hirakawa and Y. Norimatsu Diagnostic value of urine erythrocyte morphology in the detection of glomerular disease in SurePath? liquid‐based cytology compared with fresh urine sediment examination Objective: To assess whether the morphology of urine erythrocytes can be an effective tool for distinguishing glomerular disease from lower urinary tract disease in SurePath? liquid‐based cytology (SP‐LBC). Methods: We examined four morphological parameters of erythrocytes: (1) irregular erythrocytes (of all types including fragmented forms) comprising greater than or equal to 20% of erythrocytes; (2) uniform erythrocytes (>80%); (3) doughnut or target‐like shaped (D/T) erythrocytes (≥1%); and (4) acanthocytes (≥1%) in glomerular disease (n = 32) and lower urinary tract disease (n = 20) with SP‐LBC slides in cases that had also been assessed by fresh urine sediment examination. Results: Sensitivity of D/T erythrocytes and acanthocytes (dysmorphic erythrocytes) for glomerular disease were 100% and 87.5%, respectively, with urine sediment examination, and 81.3% and 46.9%, respectively, in SP‐LBC slides. Specificity was 100% for D/T erythrocytes and acanthocytes using either procedure. While irregular erythrocytes were specific for glomerular disease using urine sediment examination, they were seen in 70% of those with lower urinary tract disease using SP‐LBC slides as a result of the deformation of erythrocytes by the fixative. Conclusions: Although the sensitivity of D/T erythrocytes and acanthocytes for glomerular disease was lower in SP‐LBC slides than fresh urine sediment examination, their specificity was equally high. Therefore, urine erythrocyte morphology is useful in the detection of glomerular disease with the SP‐LBC slides. However, morphological features apart from D/T erythrocytes and acanthocytes are not useful in SP‐LBC slides. 相似文献
324.
Hideo Ochiai Hiroshi Eguchi Shunsuke Noguchi Yutaro Hayashi Hideaki Nishino Masaru Kawamura Chau H. Wu 《Journal of molecular recognition : JMR》2013,26(1):32-37
Glutathione S‐transferase (GST) was found to complex with the Na+,K+‐ATPase as shown by binding assay using quartz crystal microbalance. The complexation was obstructed by the addition of antiserum to the α‐subunit of the Na+,K+‐ATPase, suggesting the specificity of complexation between GST and the Na+,K+‐ATPase. Co‐immunoprecipitation experiments, using the anti‐α‐subunit antiserum to precipitate the GST‐Na+,K+‐ATPase complex and then using antibodies specific to an isoform of GST to identify the co‐precipitated proteins, revealed that GSTπ was complexed with the Na+,K+‐ATPase. GST stimulated the Na+,K+‐ATPase activity up to 1.4‐fold. The level of stimulation exhibited a saturable dose–response relationship with the amount of GST added, although the level of stimulation varied depending on the content of GSTπ in the lots of GST received from supplier. The stimulation was also obtained when recombinant GSTπ was used, confirming the results. When GST was treated with reduced glutathione, GST activity was greatly stimulated, whereas the level of stimulation of the Na+,K+‐ATPase activity was similar to that when untreated GST was added. When GST was treated with H2O2, GST activity was greatly diminished while the stimulation of the Na+,K+‐ATPase activity was preserved. The results suggest that GSTπ complexes with the Na+,K+‐ATPase and stimulates the latter independent of its GST activity. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
325.
Akira Hayashi Kyosuke Kinoshita Yoshihiko Kotani 《Bioscience, biotechnology, and biochemistry》2013,77(8):1705-1709
The phase change for an amylose–butanol complex solution in 10% of dimethylsulfoxide was investigated as a function of temperature. The phase change was determined with measurements of the turbidity, fluorescent depolarization, and viscosity. The phase diagram obtained was qualitatively similar to that for an amylose solution. From the result, the change in solution phase for the amylose–butanol complex is suggested to be similar to that for amylose, i.e., when the solution cools from a higher temperature, amylose molecules in the complex solution change the conformation from a random coil to an interrupted helix, and then separate into two phases. Coacervate particles resulting from the phase separation coalesce with each other to yield precipitates.An adsorption of uranine on amylose was studied to ascertain its relationship with the fluorescent depolarization method used for detecting phase changes in solution. The result showed that uranine was adsorbed on amylose chains but not on the amylose–butanol complex. 相似文献
326.
Izumi Yajima Mikio Nakamura Hidemasa Sakakibara Junichi Ide Tetsuya Yanai Kazuo Hayashi 《Bioscience, biotechnology, and biochemistry》2013,77(8):1755-1760
The aqueous extract of dried bonito (Katsuobushi) was distilled under reduced pressure. The resulting distillate with diethyl ether and the extract was separated into acidic, phenolic, basic and neutral fractions. The neutral fraction was further fractionated into ten sub-fractions by silica gel column chromatography. All these sub-fractions were analyzed by gas chromatography and gas chromatography-mass spectrometry.One hundred and sixty-five compounds were identified and 12 compounds were tentatively identified from the neutral fraction. Among them, 111 compounds were newly identified as flavor components of Katsuobushi. 相似文献
327.
Osamu Hayashi Haruki Yamada Toshio Miyazaki 《Bioscience, biotechnology, and biochemistry》2013,77(8):1643-1645
The reactions of N-acetylchitooligosaccharides with chitinolytic enzyme were analyzed by HPLC using a Tosoh TSK-Gel amide-80 column with 70% acetonitrile as an eluent. We separated α and β anomeric forms of N-acetylchitooligosaccharides, and obtain the following advantages of this HPLC method.1. We can easily identify the reaction mechanism of chitinolytic enzymes by this method, distinguishing the inverting mechanism showing α anomer formation from the retaining mechanism showing β anomer formation.2. We can also estimate the cleavage patterns of N-acetylchitooligosaccharides by chitinolytic enzymes by using natural substrates. 相似文献
328.
Hiromi Toyama Eriko Hayashi Kozo Nagaoka Yujiro Yamada 《Bioscience, biotechnology, and biochemistry》2013,77(8):1859-1864
To establish a procedure for high frequency transfection in streptomycetes, the conditions and factors affecting the polyethyleneglycol (PEG) mediated transfection of S. chartreusis SF1623 by actinophage Φr5 DNA were studied. Protoplasts of S. chartreusis SF1623 prepared by treatment with lysozyme and achromopeptidase were very stable. Protoplasts from 20 to 22hr culture cells were more competent for transfection. The optimal pH of the medium for transfection was pH 7.6. The presence of NaCl, thymidine, ATP, ADP or adenosine in the transfection medium enhanced the frequency of transfection. The optimal conditions determined for protoplast transfection were 12.5% PEG 4,000, 300 mm NaCl, 1 mm thymidine, final concentration, Φr5 DNA and protoplasts in P3 medium (pH 7.6). The frequency of transfection under the optimal conditions was 5 × 105 per μg Φr5 DNA and was about 3 × 10?3 per regenerated protoplasts.Progenitively mature phages appeared 4hr after incubation in the regeneration solution and their number continued to increase for about 11 hr. The burst size was estimated to be about 400. 相似文献
329.
Yoshinobu Naoshima Takahiro Makita Hirokiyo Kondo Shûichi Hayashi 《Bioscience, biotechnology, and biochemistry》2013,77(6):1703-1704
A hydrogen bacterium strain, N34, and its oxygen-resistant segregant strain, Y38, were subjected to a taxonomical study. Since both strains were capable of N2-fixation, N2-fixing facultative hydrogen autotrophs listed in “Bergey’s Manual of Systematic Bacteriology” were used for comparison. Both strains produced a water-insoluble carotenoid pigment, zeaxanthin dirhamnoside, indicating that both should be classified into the genus Xanthobacter. Then, the differential characteristics of the two species of the genus Xanthobacter, X. autotrophicus and X. flavus, were investigated as to both strains. The vitamin requirement, the sensitivity to oxygen under autotrophic conditions, the inducibility of hydrogenase, the substrate range of carbohydrates and N2-fixing growth characteristics of both strains were almost completely opposite to those of X. flavus. Moreover, both strains coincided exactly with X. autotrophicus in morphological and other physiological characteristics. From these results both strains were identified as Xanthobacter autotrophicus. 相似文献
330.
Kimiko Anno Hisako Terahata Yutsuki Hayashi Nobuko Seno 《Bioscience, biotechnology, and biochemistry》2013,77(5):495-499
A highly purified fucoidin was isolated from Pelvetia wrightii by an improved method, which involves the removal of alginate with calcium chloride solution and purification with cetylpyridinium chloride (CPC).To this end, the critical salt concentrations of the cetylpyridinium complex of alginic acid and fucoidin in salt solutions (KCl, NaCl, CaCl2) were determined.The fucoidin of this alga contained both fucose and galactose as its constituents, in a ratio of approximately 10:1, and it is considered to be a galactofucan sulfate. 相似文献