全文获取类型
收费全文 | 1673篇 |
免费 | 119篇 |
出版年
2022年 | 12篇 |
2021年 | 27篇 |
2020年 | 11篇 |
2019年 | 18篇 |
2018年 | 22篇 |
2017年 | 20篇 |
2016年 | 30篇 |
2015年 | 47篇 |
2014年 | 56篇 |
2013年 | 93篇 |
2012年 | 107篇 |
2011年 | 102篇 |
2010年 | 65篇 |
2009年 | 65篇 |
2008年 | 115篇 |
2007年 | 91篇 |
2006年 | 89篇 |
2005年 | 90篇 |
2004年 | 92篇 |
2003年 | 80篇 |
2002年 | 81篇 |
2001年 | 28篇 |
2000年 | 23篇 |
1999年 | 26篇 |
1998年 | 25篇 |
1997年 | 19篇 |
1996年 | 13篇 |
1995年 | 20篇 |
1994年 | 17篇 |
1993年 | 10篇 |
1992年 | 24篇 |
1991年 | 27篇 |
1990年 | 25篇 |
1989年 | 20篇 |
1988年 | 19篇 |
1987年 | 13篇 |
1986年 | 25篇 |
1985年 | 10篇 |
1984年 | 19篇 |
1983年 | 10篇 |
1982年 | 13篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1970年 | 11篇 |
1969年 | 5篇 |
1967年 | 4篇 |
排序方式: 共有1792条查询结果,搜索用时 46 毫秒
71.
Mayu Miyanohara Susumu Imai Masaaki Okamoto Wataru Saito Yoshiaki Nomura Yasuko Momoi Masaki Tomonaga Nobuhiro Hanada 《Microbiology and immunology》2013,57(5):359-365
The aim of this study was to analyze the distribution and phenotypic properties of the indigenous streptococci in chimpanzee (Pan troglodytes) oral cavities. Eleven chimpanzees (aged from 9 to 44 years, mean ± SD, 26.9 ± 12.6 years) in the Primate Research Institute of Kyoto University were enrolled in this research and brushing bacterial samples collected from them. Streptococci were isolated from the oral cavities of all chimpanzees. The isolates (n = 46) were identified as thirteen species by 16S rRNA genes analysis. The predominant species was Streptococcus sanguinis of mitis streptococci from five chimpanzees (45%). Mutans streptococci were isolated from six chimpanzees (55%). The predominant species in the mutans streptococci were Streptococcus troglodytae from four chimpanzees (36%), this species having been proposed as a novel species by us, and Streptococcus dentirousetti from three chimpanzees (27%). Streptococcus mutans was isolated from one chimpanzee (9%). However, Streptococcus sobrinus, Streptococcus macacae and Streptococcus downei, which are indigenous to human and monkey (Macaca fasciclaris) oral habitats, were not isolated. Of the mutans streptococci, S. troglodytae, S. dentirousetti, and S. mutans possessed strong adherence activity to glass surface. 相似文献
72.
Takahiro Inoue Kyosuke Takao Takashi Yoshida Kei Wada Takashi Daifuku Yasuko Yoneda Keiichi Fukuyama Yoshihiko Sako 《Biochemical and biophysical research communications》2013
A unique [Ni–Fe–S] cluster (C-cluster) constitutes the active center of Ni-containing carbon monoxide dehydrogenases (CODHs). His261, which coordinates one of the Fe atoms with Cys295, is suggested to be the only residue required for Ni coordination in the C-cluster. To evaluate the role of Cys295, we constructed CODH-II variants. Ala substitution for the Cys295 substitution resulted in the decrease of Ni content and didn’t result in major change of Fe content. In addition, the substitution had no effect on the ability to assemble a full complement of [Fe–S] clusters. This strongly suggests Cys295 indirectly and His261 together affect Ni-coordination in the C-cluster. 相似文献
73.
Kentaro Takai Yasunao Inoue Yasuko Konishi Atsushi Suwa Yoshiharu Uruno Harumi Matsuda Tomokazu Nakako Mutsuko Sakai Hiroyuki Nishikawa Gakuji Hashimoto Takeshi Enomoto Atsushi Kitamura Yasuaki Uematsu Akihiko Kiyoshi Takaaki Sumiyoshi 《Bioorganic & medicinal chemistry letters》2013,23(16):4644-4647
We designed and synthesized N-substituted 8-azatetrahydroquinolone derivatives as selective M1 and M4 muscarinic acetylcholine receptors agonists. Optimization of selected derivatives led to the discovery of compound 7 as a highly potent M1 and M4 agonist with weak hERG inhibition. Oral administration of compound 7 improved psychosis-like behavior in rats. 相似文献
74.
Hironobu Morinaga Seiichiro Kizaki Tomohiro Takenaka Shuhei Kanesato Yuta Sannohe Ryu Tashiro Hiroshi Sugiyama 《Bioorganic & medicinal chemistry》2013,21(2):466-469
5-Bromouracil (BrU) was incorporated into three types of synthetic RNA and the products of the photoirradiated BrU-containing RNAs were investigated using HPLC and MS analysis. The photoirradiation of r(GCABrUGC)2 and r(CGAABrUUGC)/r(GCAAUUCG) in A-form RNA produced the corresponding 2′-keto adenosine (ketoA) product at the 5′-neighboring nucleotide, such as r(GCketoAUGC) and r(CGAketoAUUGC), respectively. The photoirradiation of r(CGCGBrUGCG)/r(CmGCACmGCG) in Z-form RNA produced the 2′-keto guanosine (ketoG) product r(CGCketoGUGCG), whereas almost no products were observed from the photoirradiation of r(CGCGBrUGCG)/r(CmGCACmGCG) in A-form RNA. The present results indicate clearly that hydrogen (H) abstraction by the photochemically generated uracil-5-yl radical selectively occurs at the C2′ position to provide a 2′-keto RNA product. 相似文献
75.
76.
The amino acid sequence of Indian peafowl egg-white lysozyme has been identified. The reduced and carboxymethylated lysozyme was digested with trypsin followed by purification of the resulting peptides by reverse-phase HPLC. The tryptic peptides obtained were sequenced using the DABITC/PITC double coupling manual sequencing method. The alignment of the tryptic peptides were deduced by comparison with corresponding peptides of hen egg-white lysozyme. This protein proved to consist of 129 amino acid residues, and a relative molecular mass of 14423 Da was calculated. Amino acid sequence comparison of peafowl lysozyme and other phasianoid bird lysozymes revealed a maximum homology ratio of 98% with turkey lysozyme. 相似文献
77.
78.
Yoshimasa Taniguchi Yasuko Matsukura Harumi Taniguchi Hideki Koizumi Mikio Katayama 《Bioscience, biotechnology, and biochemistry》2013,77(10):1684-1694
The bitter acids in hops (Humulus lupulus L.) and beer, such as α-, β-, and iso-α-acids, are known to affect beer quality and display various physiological effects. However, these compounds readily oxidize, and the effect of the oxides on the properties of beer or their potential health benefits are not well understood. In this study, we developed a simple preparative method for the bitter acid oxide fraction derived from hops and designated the constituents as matured hop bitter acids (MHBA). HPLC-PDA-ESI/HRMS and MS2 revealed that MHBA are primarily composed of α-acid-derived oxides, which possess a common β-tricarbonyl moiety in their structures similar to α-, β-, and iso-α-acids. We also developed a quantitative analytical method of whole MHBA by HPLC, which showed high precision and reproducibility. Using our newly developed method, the concentration of whole MHBA in several commercial beers was evaluated. Our results will promote the study of bitter acid oxides. 相似文献
79.
Akihito Tanaka Knut Woltjen Katsuya Miyake Akitsu Hotta Makoto Ikeya Takuya Yamamoto Tokiko Nishino Emi Shoji Atsuko Sehara-Fujisawa Yasuko Manabe Nobuharu Fujii Kazunori Hanaoka Takumi Era Satoshi Yamashita Ken-ichi Isobe En Kimura Hidetoshi Sakurai 《PloS one》2013,8(4)
The establishment of human induced pluripotent stem cells (hiPSCs) has enabled the production of in vitro, patient-specific cell models of human disease. In vitro recreation of disease pathology from patient-derived hiPSCs depends on efficient differentiation protocols producing relevant adult cell types. However, myogenic differentiation of hiPSCs has faced obstacles, namely, low efficiency and/or poor reproducibility. Here, we report the rapid, efficient, and reproducible differentiation of hiPSCs into mature myocytes. We demonstrated that inducible expression of myogenic differentiation1 (MYOD1) in immature hiPSCs for at least 5 days drives cells along the myogenic lineage, with efficiencies reaching 70–90%. Myogenic differentiation driven by MYOD1 occurred even in immature, almost completely undifferentiated hiPSCs, without mesodermal transition. Myocytes induced in this manner reach maturity within 2 weeks of differentiation as assessed by marker gene expression and functional properties, including in vitro and in vivo cell fusion and twitching in response to electrical stimulation. Miyoshi Myopathy (MM) is a congenital distal myopathy caused by defective muscle membrane repair due to mutations in DYSFERLIN. Using our induced differentiation technique, we successfully recreated the pathological condition of MM in vitro, demonstrating defective membrane repair in hiPSC-derived myotubes from an MM patient and phenotypic rescue by expression of full-length DYSFERLIN (DYSF). These findings not only facilitate the pathological investigation of MM, but could potentially be applied in modeling of other human muscular diseases by using patient-derived hiPSCs. 相似文献