全文获取类型
收费全文 | 2053篇 |
免费 | 87篇 |
出版年
2023年 | 6篇 |
2022年 | 15篇 |
2021年 | 22篇 |
2020年 | 18篇 |
2019年 | 9篇 |
2018年 | 10篇 |
2017年 | 14篇 |
2016年 | 23篇 |
2015年 | 33篇 |
2014年 | 55篇 |
2013年 | 129篇 |
2012年 | 87篇 |
2011年 | 102篇 |
2010年 | 80篇 |
2009年 | 77篇 |
2008年 | 113篇 |
2007年 | 117篇 |
2006年 | 137篇 |
2005年 | 109篇 |
2004年 | 136篇 |
2003年 | 107篇 |
2002年 | 141篇 |
2001年 | 51篇 |
2000年 | 41篇 |
1999年 | 49篇 |
1998年 | 24篇 |
1997年 | 27篇 |
1996年 | 21篇 |
1995年 | 35篇 |
1994年 | 26篇 |
1993年 | 20篇 |
1992年 | 32篇 |
1991年 | 25篇 |
1990年 | 21篇 |
1989年 | 26篇 |
1988年 | 23篇 |
1987年 | 20篇 |
1986年 | 22篇 |
1985年 | 18篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 14篇 |
1980年 | 9篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1975年 | 12篇 |
1974年 | 10篇 |
1973年 | 8篇 |
排序方式: 共有2140条查询结果,搜索用时 15 毫秒
941.
Michael Blaise Cook Zhaoming Wang Edward D. Yeboah Yao Tettey Richard B. Biritwum Andrew A. Adjei Evelyn Tay Ann Truelove Shelley Niwa Charles C. Chung Annand P. Chokkalingam Lisa W. Chu Meredith Yeager Amy Hutchinson Kai Yu Kristin A. Rand Christopher A. Haiman Robert N. Hoover Ann W. Hsing Stephen J. Chanock 《Human genetics》2014,133(5):509-521
Age-adjusted mortality rates for prostate cancer are higher for African-American men compared with those of European ancestry. Recent data suggest that West African men also have elevated risk for prostate cancer relative to European men. Genetic susceptibility to prostate cancer could account for part of this difference. We conducted a genome-wide association study (GWAS) of prostate cancer in West African men in the Ghana Prostate Study. Association testing was performed using multivariable logistic regression adjusted for age and genetic ancestry for 474 prostate cancer cases and 458 population-based controls on the Illumina HumanOmni-5 Quad BeadChip. The most promising association was at 10p14 within an intron of a long non-coding RNA (lncRNA RP11-543F8.2) 360 kb centromeric of GATA3 (p = 1.29E?7). In sub-analyses, SNPs at 5q31.3 were associated with high Gleason score (≥7) cancers, the strongest of which was a missense SNP in PCDHA1 (rs34575154, p = 3.66E?8), and SNPs at Xq28 (rs985081, p = 8.66E?9) and 6q21 (rs2185710, p = 5.95E?8) were associated with low Gleason score (<7) cancers. We sought to validate our findings in silico in the African Ancestry Prostate Cancer GWAS Consortium, but only one SNP, at 10p14, replicated at p < 0.05. Of the 90 prostate cancer loci reported from studies of men of European, Asian or African-American ancestry, we were able to test 81 in the Ghana Prostate Study, and 10 of these replicated at p < 0.05. Further genetic studies of prostate cancer in West African men are needed to confirm our promising susceptibility loci. 相似文献
942.
Identification of two teleost homologs of the Drosophila sex determination factor, transformer-2 in medaka (Oryzias latipes) 总被引:3,自引:0,他引:3
Shiraishi E Imazato H Yamamoto T Yokoi H Abe S Kitano T 《Mechanisms of development》2004,121(7-8):991-996
Transformer-2 (Tra2), an RNA-binding protein, is an important regulator in Drosophila sex determination. In vertebrates, however, the role of Tra2 homologues is not known. We identified two teleost homologues of Tra2, which we named Tra2a and Tra2b, in medaka (Oryzias latipes). Furthermore, we demonstrated that both Tra2 mRNAs were predominantly expressed in germ cells of both sexes before the onset of sex differentiation, suggesting that both Tra2 homologues might be involved in the sex differentiation in medaka. 相似文献
943.
944.
Akira Yoshioka Taku Kadoya Shin-ichi Suda Izumi Washitani 《Biological invasions》2010,12(8):2789-2796
To examine the relative importance and interactions of trophic and non-trophic effects of plant invasions on herbivores, we
investigated how the invasion of weeping lovegrass Eragrostis curvula impacted Eusphingonotus japonicus, a food generalist grasshopper endemic to gravelly floodplains with sparse vegetation in Japan. Field observations and laboratory
experiments showed that the grasshopper fed mainly on herbs endemic to the gravelly floodplains, which were negatively impacted
by the alien grass. The alien grass was not consumed as food. Field censuses also showed that the abundance of the grasshopper
was positively correlated with the coverage of endemic herbs in a plot where weeping lovegrass was not dominant. Dominance
of the grass (i.e., habitat modification for E. japonicus) negatively impacted the grasshopper and weakened the positive relationship between the grasshopper and endemic herbs. These
results suggest that an understanding of the relationship between non-trophic and trophic effects is essential to predict
the impacts of plant invasions on herbivores. 相似文献
945.
946.
Kengo Sasaki Masahiko Morita Shin-ichi Hirano Daisuke Sasaki Naoya Ohmura Yasuo Igarashi 《Applied microbiology and biotechnology》2010,87(4):1579-1586
We have reported for the first time that agricultural and cellulosic waste, i.e., rice straw was directly applied to methanogenic
bioreactors containing carbon fiber textiles (CFT) as supporting material. Addition of CFT to the methanogenic bioreactors
enhanced the conversion of dichromate chemical oxygen demand of the substrate to methane (41%) to a greater extent than bioreactors
without CFT (9%). In addition, removal of rice straw as a suspended solid was increased from 31% (in bioreactors without CFT)
to 57% (in those with CFT). Methanogenic 16S rRNA gene analysis showed that the abundance of acetoclastic methanogen, genus
Methanosarcina, was about 11 times higher in bioreactors with CFT (suspended fraction plus retained fraction to CFT) than in bioreactors
without CFT (suspended fraction), resulting in lower concentration of acetate in bioreactors with CFT (0.4 mM) than in those
without CFT (29.7 mM). On the other hand, the abundance of hydrogenotrophic methanogen, genus Methanobacterium, in bioreactors with CFT was similar to those without CFT. Bacterial communities in bioreactors with CFT were different from
those in bioreactors without CFT. Our results indicated that specific microbial community and cooperative relationships between
microorganisms in reactors containing CFT facilitated efficient decomposition of rice straw and its conversion to methane. 相似文献
947.
Noriyuki Kasai Shin-ichi Ikushiro Raku Shinkyo Kaori Yasuda Shinji Hirosue Akira Arisawa Hirofumi Ichinose Hiroyuki Wariishi Toshiyuki Sakaki 《Applied microbiology and biotechnology》2010,86(2):773-780
The white-rot fungus Phanerochaete chrysosporium possesses biodegradative capabilities of polychlorinated dibenzo-p-dioxins (PCDDs). One hundred twenty yeast clones expressing individual P450s of P. chrysosporum (PcCYPs), generated in our previous efforts, were screened for transformation of dioxin, and 40 positive clones were obtained.
Of these clones, six clones showed metabolism of 2-chloro-dibenzo-p-dioxin, and a microsomal PcCYP designated as PcCYP11a3 showed much higher activity than any other PcCYPs. The turnover numbers
of hydroxylation activities of PcCYP11a3 toward 1-MCDD (58 min−1) and 2-MCDD (13 min−1) are more than 200 times higher than those of previously reported PcCYP65a2. In addition, PcCYP11a3 catalyzes hydroxylation
of 2,3-dichloro-dibenzo-p-dioxin. To our best knowledge, PcCYP11a3 has the highest activity toward PCDDs among the known CYPs derived from microorganisms.
Although PcCYP11a3 showed no detectable activity toward 2,7-dichloro-dibenzo-p-dioxin and 2,3,7-trichloro-dibenzo-p-dioxin, PcCYP11a3 is promising as a template whose activity would be enhanced by site-directed mutagenesis. 相似文献
948.
Katsuhiko Takahashi Naoko Sasabe Kumiko Ohshima Keiko Kitazato Rina Kato Yutaka Masuda Mika Tsurumaki Takashi Obama Shin-ichi Okudaira Junken Aoki Hiroyuki Arai Tomohiro Yamaguchi Hiroyuki Itabe 《Journal of lipid research》2010,51(9):2571-2580
Cellular lipid droplets (LD) are organelles involved in cellular lipid metabolism. When liver cellular components were fractionated using sucrose density gradient centrifugation, adipose differentiation-related protein (ADRP) was distributed in both the top and bottom fractions, which correspond to the LD and membranous fractions, respectively, in the mouse liver under normal feeding conditions. After overnight fasting, triacylglycerol and ADRP increased nearly 2.5-fold in the mouse liver, and a portion appeared in the intermediate-density LD (iLD) fractions. ADRP in the iLD fractions was also increased in a mouse nonalcoholic steatohepatitis model induced by methione/choline-deficient diet. When HuH-7 human hepatoma cells were incubated with oleic acid for 24 h, the amount of ADRP increased, and it was distributed in both the LD and membrane fractions. However, ADRP appeared in the iLD fractions upon treatment of HuH-7 cells with glucagon. This behavior of ADRP was cAMP-dependent, as the ADRP-positive iLD fractions were induced by dibutylyl cAMP and were blocked by protein kinase A inhibitors. A portion of ADRP colocalized microscopically with calnexin, which is present in the iLD fractions, by treatment of HuH-7 cells or human primary hepatocytes with oleic acid and glucagon, but not by treatment with oleic acid alone. Glucagon has a role in the reorganization of endoplasmic reticulum membranes to generate ADRP-associated lipid-poor particles in hepatic cells, which is related to LD formation during lipid storage. 相似文献
949.
950.
Bilirubin oxidase activity of Bacillus subtilis CotA 总被引:1,自引:0,他引:1
Sakasegawa S Ishikawa H Imamura S Sakuraba H Goda S Ohshima T 《Applied and environmental microbiology》2006,72(1):972-975
The spore coat protein CotA from Bacillus subtilis was previously identified as a laccase. We have now found that CotA also shows strong bilirubin oxidase activity and markedly higher affinity for bilirubin than conventional bilirubin oxidase. This is the first characterization of bilirubin oxidase activity in a bacterial protein. 相似文献