全文获取类型
收费全文 | 2011篇 |
免费 | 123篇 |
出版年
2021年 | 24篇 |
2020年 | 18篇 |
2019年 | 18篇 |
2018年 | 25篇 |
2017年 | 31篇 |
2016年 | 41篇 |
2015年 | 58篇 |
2014年 | 73篇 |
2013年 | 111篇 |
2012年 | 118篇 |
2011年 | 124篇 |
2010年 | 82篇 |
2009年 | 79篇 |
2008年 | 103篇 |
2007年 | 107篇 |
2006年 | 99篇 |
2005年 | 121篇 |
2004年 | 86篇 |
2003年 | 91篇 |
2002年 | 90篇 |
2001年 | 69篇 |
2000年 | 57篇 |
1999年 | 56篇 |
1998年 | 14篇 |
1997年 | 15篇 |
1996年 | 14篇 |
1995年 | 15篇 |
1994年 | 14篇 |
1993年 | 15篇 |
1992年 | 33篇 |
1991年 | 23篇 |
1990年 | 31篇 |
1989年 | 30篇 |
1988年 | 27篇 |
1987年 | 21篇 |
1986年 | 37篇 |
1985年 | 26篇 |
1984年 | 26篇 |
1983年 | 18篇 |
1982年 | 10篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1976年 | 4篇 |
1975年 | 13篇 |
1974年 | 5篇 |
1972年 | 8篇 |
1971年 | 7篇 |
1970年 | 5篇 |
排序方式: 共有2134条查询结果,搜索用时 15 毫秒
891.
Subcellular fractions from developing seeds of mustard (Sinapis alba), honesty (Lunaria annua) and nasturtium (Tropaeolum majus) synthesize very long chain cis (n−9) monounsaturated fatty acids, e.g. gadoleic (20:1), erucic (22:1) and nervonic (24:1) acid, from oleoyl-CoA and malonyl-CoA by condensation reactions. The particulate 2000 × g and 15 000 × g fractions exhibit considerably higher elongase activities compared to the microsomal or oil body fractions, whereas the soluble (150 000 × g supernatant) fraction is devoid of such activities. 相似文献
892.
H Ohashi Y Katsuta T Hashizume S N Abe H Kajiura H Hattori T Kamei M Yano 《Applied and environmental microbiology》1988,54(11):2603-2607
Penicillin G acylase was purified from the cultured filtrate of Arthrobacter viscosus 8895GU and was found to consist of two distinct subunits with apparent molecular weights of 24,000 (alpha) and 60,000 (beta). The partial N-terminal amino acid sequences of the alpha and beta subunits were determined with a protein gas phase sequencer, and a 29-base oligonucleotide corresponding to the partial amino acid sequence of the alpha subunit was synthesized. An Escherichia coli transformant having the penicillin G acylase gene was isolated from an A. viscosus gene library by hybridization with the 29-base probe. The resulting positive clone was further screened by the Serratia marcescens overlay technique. E. coli carrying a plasmid designated pHYM-1 was found to produce penicillin G acylase in the cells. This plasmid had an 8.0-kilobase pair DNA fragment inserted in the EcoRI site of pACYC184. 相似文献
893.
TaqI polymorphism in the LDL receptor gene and a TaqI 1.5-kb band associated with familial hypercholesterolemia 总被引:1,自引:1,他引:0
Kimiko Yamakawa Takaaki Okafuji Yukio Iwamura Kenji Yuzawa Juichi Satoh Naoko Hattori Yasuko Yamanouchi Hisako Yanagi Koichi Kawai Shigeru Tsuchiya David W. Russell Hideo Hamaguchi 《Human genetics》1988,80(1):1-5
Summary The low density lipoprotein (LDL) receptor gene was analyzed in 67 unrelated healthy Japanese and 38 members of six consecutive families with familial hypercholesterolemia (FH) by Southern blot hybridization with TaqI, an LDL receptor cDNA fragment containing exons 1 to 8 being used as a probe. A new TaqI RFLP at the LDL receptor locus was detected with allele frequencies of 0.67 and 0.33. The data obtained with smaller cDNA subfragment probes revealed that the TaqI RFLP site is located within 1.1 kb of the 5 side of the EcoRI site of exon 5. The TaqI RFLP was in linkage disequilibrium with the PstI RFLP but showed no significant linkage disequilibrium with the RFLPs for AvaII, ApaLI/I15, PvuII, NcoI, and ApaLI/3. Among the seven RFLPs at the LDL receptor locus, the TaqI RFLP was the only useful genetic marker in one of the six families with FH. Furthermore, the association of an additional TaqI 1.5-kb band with a mutant LDL receptor gene was observed in another family with FH in which the proband was homozygous for all of the seven RFLPs. The data obtained with various restriction enzymes and smaller cDNA subfragments probes suggested that a minor change in nucleotide sequences in the region including exons 5 to 8 is present in the mutant gene. These data suggest that the TaqI RFLP is a useful genetic marker at the LDL receptor locus and that TaqI serves for the analysis of some mutant LDL receptor genes, when used with small LDL receptor cDNA probes. 相似文献
894.
T Kumazawa O Suzuki H Seno H Hattori 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1988,91(2):571-574
1. beta-Phenylethylamine (PEA) was detected and quantitated in tissues of the catfish, Parasilurus asotus, by very specific and sensitive gas chromatography/mass spectrometry. 2. The selected ion monitoring was made with a strong quasi-molecular ion of the pentafluoropropionic derivative of PEA in the positive chemical ionization mode. 3. PEA was found in all tissues tested ranging from 2.8 to 38.2 ng/g wet wt tissue. It was highest in the spinal cord, followed by the skin, brain and intestine. 相似文献
895.
Natsuko Kondo Hiroyuki Michiue Yoshinori Sakurai Hiroki Tanaka Yosuke Nakagawa Tsubasa Watanabe Masaru Narabayashi Yuko Kinashi Minoru Suzuki Shin-ichiro Masunaga Koji Ono 《Reports of Practical Oncology and Radiotherapy》2016,21(2):108-112
Aim
In this study, we investigated γH2AX foci as markers of DSBs in normal brain and brain tumor tissue in mouse after BNCT.Background
Boron neutron capture therapy (BNCT) is a particle radiation therapy in combination of thermal neutron irradiation and boron compound that specifically accumulates in the tumor. 10B captures neutrons and produces an alpha (4He) particle and a recoiled lithium nucleus (7Li). These particles have the characteristics of extremely high linear energy transfer (LET) radiation and therefore have marked biological effects. High LET radiation causes severe DNA damage, DNA DSBs. As the high LET radiation induces complex DNA double strand breaks (DSBs), large proportions of DSBs are considered to remain unrepaired in comparison with exposure to sparsely ionizing radiation.Materials and methods
We analyzed the number of γH2AX foci by immunohistochemistry 30 min or 24 h after neutron irradiation.Results
In both normal brain and brain tumor, γH2AX foci induced by 10B(n,α)7Li reaction remained 24 h after neutron beam irradiation. In contrast, γH2AX foci produced by γ-ray irradiation at contaminated dose in BNCT disappeared 24 h after irradiation in these tissues.Conclusion
DSBs produced by 10B(n,α)7Li reaction are supposed to be too complex to repair for cells in normal brain and brain tumor tissue within 24 h. These DSBs would be more difficult to repair than those by γ-ray. Excellent anti-tumor effect of BNCT may result from these unrepaired DSBs induced by 10B(n,α)7Li reaction. 相似文献896.
Nobuyuki Matsumoto Hiroki Ikeda Ryuta Shigefuku Nobuhiro Hattori Tsunamasa Watanabe Kotaro Matsunaga Tetsuya Hiraishi Tomohiro Tamura Yohei Noguchi Yasunobu Fukuda Toshiya Ishii Chiaki Okuse Akira Sato Michihiro Suzuki Fumio Itoh 《PloS one》2016,11(3)
Background
Decreased hemoglobin (Hb) level has been supposed to be a relatively rare side effect of a combination therapy against hepatitis C virus that consists of the NS5A inhibitor daclatasvir (DCV) and the NS3/4A protease inhibitor asunaprevir (ASV).Methods
The study was conducted in 75 patients with genotype 1b chronic hepatitis C virus infection who had started combination therapy with DCV and ASV at St. Marianna University School of Medicine Hospital between September 2014 and December 2014.Results
Among the patients examined, decreased Hb level by ≥1.5 g/dL from the values at treatment initiation was observed in 11 individuals. This was accompanied by decreased mean corpuscular volume, and iron and ferritin levels.Conclusions
These findings suggest that the mechanism of the phenomenon is caused by iron deficiency. The underlying mechanism and clinical impacts will need to be further examined. 相似文献897.
Yutaka Yasui Tokiya Abe Masayuki Kurosaki Mayu Higuchi Yasuyuki Komiyama Tsubasa Yoshida Tsuguru Hayashi Konomi Kuwabara Kenta Takaura Natsuko Nakakuki Hitomi Takada Nobuharu Tamaki Shoko Suzuki Hiroyuki Nakanishi Kaoru Tsuchiya Jun Itakura Yuka Takahashi Akinori Hashiguchi Michiie Sakamoto Namiki Izumi 《PloS one》2016,11(8)
898.
Kenta?Kamatuka Masahiro?Hattori Tomoyasu?SugiyamaEmail author 《EURASIP Journal on Bioinformatics and Systems Biology》2016,2016(1):7
RNA interference (RNAi) screening is extensively used in the field of reverse genetics. RNAi libraries constructed using random oligonucleotides have made this technology affordable. However, the new methodology requires exploration of the RNAi target gene information after screening because the RNAi library includes non-natural sequences that are not found in genes. Here, we developed a web-based tool to support RNAi screening. The system performs short hairpin RNA (shRNA) target prediction that is informed by comprehensive enquiry (SPICE). SPICE automates several tasks that are laborious but indispensable to evaluate the shRNAs obtained by RNAi screening. SPICE has four main functions: (i) sequence identification of shRNA in the input sequence (the sequence might be obtained by sequencing clones in the RNAi library), (ii) searching the target genes in the database, (iii) demonstrating biological information obtained from the database, and (iv) preparation of search result files that can be utilized in a local personal computer (PC). Using this system, we demonstrated that genes targeted by random oligonucleotide-derived shRNAs were not different from those targeted by organism-specific shRNA. The system facilitates RNAi screening, which requires sequence analysis after screening. The SPICE web application is available at http://www.spice.sugysun.org/. 相似文献
899.
900.