全文获取类型
收费全文 | 1918篇 |
免费 | 94篇 |
国内免费 | 2篇 |
专业分类
2014篇 |
出版年
2023年 | 4篇 |
2022年 | 13篇 |
2021年 | 16篇 |
2020年 | 12篇 |
2019年 | 20篇 |
2018年 | 19篇 |
2017年 | 38篇 |
2016年 | 32篇 |
2015年 | 60篇 |
2014年 | 76篇 |
2013年 | 132篇 |
2012年 | 107篇 |
2011年 | 113篇 |
2010年 | 84篇 |
2009年 | 92篇 |
2008年 | 130篇 |
2007年 | 114篇 |
2006年 | 120篇 |
2005年 | 113篇 |
2004年 | 124篇 |
2003年 | 107篇 |
2002年 | 107篇 |
2001年 | 23篇 |
2000年 | 28篇 |
1999年 | 26篇 |
1998年 | 26篇 |
1997年 | 27篇 |
1996年 | 17篇 |
1995年 | 8篇 |
1994年 | 16篇 |
1993年 | 27篇 |
1992年 | 19篇 |
1991年 | 14篇 |
1990年 | 13篇 |
1989年 | 16篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1971年 | 5篇 |
1970年 | 4篇 |
1969年 | 3篇 |
1965年 | 3篇 |
排序方式: 共有2014条查询结果,搜索用时 15 毫秒
51.
Masayuki Ushio Hisato Fukuda Toshiki Inoue Kobayashi Makoto Osamu Kishida Keiichi Sato Koichi Murata Masato Nikaido Tetsuya Sado Yukuto Sato Masamichi Takeshita Wataru Iwasaki Hiroki Yamanaka Michio Kondoh Masaki Miya 《Molecular ecology resources》2017,17(6):e63-e75
Terrestrial animals must have frequent contact with water to survive, implying that environmental DNA (eDNA) originating from those animals should be detectable from places containing water in terrestrial ecosystems. Aiming to detect the presence of terrestrial mammals using forest water samples, we applied a set of universal PCR primers (MiMammal, a modified version of fish universal primers) for metabarcoding mammalian eDNA. The versatility of MiMammal primers was tested in silico and by amplifying DNAs extracted from tissues. The results suggested that MiMammal primers are capable of amplifying and distinguishing a diverse group of mammalian species. In addition, analyses of water samples from zoo cages of mammals with known species composition suggested that MiMammal primers could successfully detect mammalian species from water samples in the field. Then, we performed an experiment to detect mammals from natural ecosystems by collecting five 500‐ml water samples from ponds in two cool‐temperate forests in Hokkaido, northern Japan. MiMammal amplicon libraries were constructed using eDNA extracted from water samples, and sequences generated by Illumina MiSeq were subjected to data processing and taxonomic assignment. We thereby detected multiple species of mammals common to the sampling areas, including deer (Cervus nippon), mouse (Mus musculus), vole (Myodes rufocanus), raccoon (Procyon lotor), rat (Rattus norvegicus) and shrew (Sorex unguiculatus). Many previous applications of the eDNA metabarcoding approach have been limited to aquatic/semiaquatic systems, but the results presented here show that the approach is also promising even for forest mammal biodiversity surveys. 相似文献
52.
Hiroki Tanabe Keiichi Yoshino Katsuyoshi Ando Yoshiki Nomura Katsuhisa Ohta Kiichi Satoh Eiichiro Ichiishi Akiei Ishizuka Takaaki Otake Yutaka Kohgo Mikihiro Fujiya Toshikatsu Okumura 《Annals of clinical microbiology and antimicrobials》2018,17(1):29
Background
All Helicobacter pylori-infected patients are recommended for eradication with an appropriate regimen in each geographic area. The choice of the therapy is somewhat dependent on the antimicrobial susceptibility. The rate of clarithromycin resistance has been increasing and is associated with failure; thus, susceptibility testing is recommended before triple therapy with clarithromycin. However, antimicrobial susceptibility testing is not yet clinically available and an alternative newly developed acid inhibitor vonoprazan is used for triple therapy in Japan. The aim of this study was to determine whether vonoprazan-based triple therapy is plausible treatment in H. pylori eradication.Methods
A retrospective observational study of H. pylori eradication was conducted in a single institute. The patients who requested antimicrobial susceptibility testing were treated with susceptibility-guided proton pump inhibitor-based triple therapy in International University of Health and Welfare Hospital from 2013 to 2016. Other patients were treated with empirical treatment with a proton pump inhibitor. From 2015 to 2016, vonoprazan-based triple treatment (vonoprazan, 20 mg; amoxicillin, 750 mg; and clarithromycin, 200 or 400 mg, b.i.d.) was conducted, and its effectiveness was compared with susceptibility-guided proton pump inhibitor-based triple therapy. We also investigated the improvement in eradication rate when antimicrobial susceptibility testing was performed, and compared the outcomes of vonoprazan-based and proton pump inhibitor-based empirical therapy.Results
A total of 1355 patients who received first-line eradication treatment were enrolled in the present study. The eradication rates of the empirical proton pump inhibitor-based therapy and the vonoprazan-based therapy group in a per-protocol analysis were 86.3% (95% CI 83.8–88.8) and 97.4% (95% CI 95.7–99.1), respectively. In 212 patients who received antimicrobial susceptibility testing, the rate of clarithromycin resistant was 23.5% and the eradication rate in susceptibility-guided treatment was 95.7% (95% CI 92.9–98.4). The difference between susceptibility-guided and vonoprazan-based therapy was ??1.7% (95% CI ??4.9 to 1.5%), and the non-inferiority of vonoprazan-based triple therapy was confirmed.Conclusions
Vonoprazan-based triple therapy was effective as susceptibility-guided triple therapy for H. pylori eradication. An empirical triple therapy with vonoprazan is preferable even in area with high rates of clarithromycin-resistance.Trial registration The study was retrospectively registered in University Hospital Medical Information Network (UMIN000032351)53.
Yoshinori Sasaki Takashi Tsujii Shigeki Takeda Hideru Obinata Takashi Izumi Keiichi Yamada Ryoichi Katakai 《Journal of peptide science》2008,14(12):1251-1258
A combinatorial peptide library contains an enormous combination of amino acid sequences and drug candidates, but an effective screening strategy to identify a variety of bioactive peptides has yet to be established. In this article, a random hexapeptide library was screened to identify novel peptide ligands for a 5-oxo-ETE receptor (OXER), which is a G-protein-coupled receptor for bioactive lipids, by using an OXER-Gi1alpha fusion protein. We successfully identified 2 hexapeptides-Ac-HMQLYF-NH2 and Ac-HMWLYF-NH(2)-that exhibited agonistic activity. Although the corresponding affinities were relatively low (EC50 values of 146 and 6.7 microM, respectively), the activities were confirmed by other independent cell-based assay methods, namely, intracellular calcium mobilization and cell chemotaxis. This study demonstrates that a combinatorial peptide library may be screened using a [35S]GTPgammaS binding assay with G-protein-coupled receptor (GPCR)-Galpha fusion proteins, in general, and that of peptide ligands can be obtained even for nonpeptide receptors. 相似文献
54.
Wakayama M Yada H Kanda S Hayashi S Yatsuda Y Sakai K Moriguchi M 《Bioscience, biotechnology, and biochemistry》2000,64(1):1-8
D-Aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (Alcaligenes A-6) was strongly inactivated by diethylpyrocarbonate (DEPC). An H67N mutant was barely active, with a kcat/Km 6.3 x 10(4) times lower than that of the recombinant wild-type enzyme, while the H67I mutant lost detectable activity. The H67N mutant had almost constant Km, but greatly decreased kcat. These results suggested that His67 is essential to the catalytic event. Both H69N and H69I mutants were overproduced in the insoluble fraction. The kcat/Km of H250N mutant was reduced by a factor of 2.5 x 10(4)-fold as compared with the wild-type enzyme. No significant difference between H251N mutant and wild-type enzymes in the Km and kcat was found. The Zn content of H250N mutant was nearly half of that of wild-type enzyme. These results suggest that the His250 residue might be essential to catalysis via Zn binding. 相似文献
55.
Real-time detection of DNA hybridization on microarray using a CCD-based imaging system equipped with a rotated microlens array disk 总被引:2,自引:0,他引:2
Mogi T Hatakeyama K Taguchi T Wake H Tanaami T Hosokawa M Tanaka T Matsunaga T 《Biosensors & bioelectronics》2011,26(5):1942-1946
This work describes a novel charge-coupled device (CCD)-based imaging system (MB Biochip Reader?) for real-time detection of DNA hybridization to DNA microarrays. The MB Biochip Reader? consisted of a laser light source (532 nm), a microlens array for generation of a multi-beam laser, and a CCD for 2-D signal imaging. The MB Biochip Reader? with a rotated microlens array, allowed large-field imaging (6.2 mm × 7.6 mm with 6.45 μm resolution) with fast time-resolution at 0.2 s without speckle noise. Furthermore, real-time detection of DNA hybridization, which is sufficient to obtain accurate data from tens of thousands of array element per field, was successfully performed without the need for laser scanning. The performance of the MB Biochip Reader? for DNA microarray imaging was similar to the commercially available photomultiplier tube (PMT)-based microarray scanner, ScanArray Lite. The system potentially could be applied toward real-time analysis in many other fluorescent techniques in addition to real-time DNA microarray analysis. 相似文献
56.
57.
In this paper, four fungi collected in Nansei Islands are reported. One is Strasseria garciniae, which must be transferred to the genus Phyllosticta. This fungus was collected in Okinawa Main Island and Iriomote Island. The other three fungi are newly added to the Japanese fungal flora. Phyllosticta ghaesembillae on Codiaeum variegatum and Cercospora asplenii on Asplenium antiquum were collected in Yoron Island. The last one, Coniella australiensis on Eucalyptus robusta was collected in Okinawa Main Island. Their morphology and symptoms on the host plant are described, with some mycological notes. 相似文献
58.
59.
60.
Ben?Jomàa-Jemili?Mariem Teruyo?ItoEmail author Meng?Zhang Jingxun?Jin Shanshuang?Li Boutiba-Ben?Boubaker?Ilhem Hammami?Adnan Xiao?Han Keiichi?Hiramatsu 《BMC microbiology》2013,13(1):2