全文获取类型
收费全文 | 1817篇 |
免费 | 88篇 |
出版年
2022年 | 9篇 |
2021年 | 33篇 |
2020年 | 10篇 |
2019年 | 26篇 |
2018年 | 38篇 |
2017年 | 24篇 |
2016年 | 45篇 |
2015年 | 52篇 |
2014年 | 72篇 |
2013年 | 94篇 |
2012年 | 137篇 |
2011年 | 137篇 |
2010年 | 80篇 |
2009年 | 69篇 |
2008年 | 123篇 |
2007年 | 115篇 |
2006年 | 110篇 |
2005年 | 88篇 |
2004年 | 95篇 |
2003年 | 85篇 |
2002年 | 73篇 |
2001年 | 29篇 |
2000年 | 20篇 |
1999年 | 24篇 |
1998年 | 18篇 |
1997年 | 27篇 |
1996年 | 20篇 |
1995年 | 14篇 |
1994年 | 16篇 |
1993年 | 9篇 |
1992年 | 26篇 |
1991年 | 23篇 |
1990年 | 21篇 |
1989年 | 15篇 |
1988年 | 15篇 |
1987年 | 12篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1977年 | 4篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1970年 | 4篇 |
1969年 | 4篇 |
1968年 | 4篇 |
排序方式: 共有1905条查询结果,搜索用时 15 毫秒
241.
Yumiko Teramoto Hiromi Tokura Kaori Ohkura Yasue Ohmasa Satsuki Suho Ryo Inoshiri Masaaki Masuda 《Journal of thermal biology》1996,21(5-6):339-343
- 1. 1. The study aimed at knowing whether thermal sensation during afternoon cool exposure could be influenced by bright light (4000 lx) or dim light (200 lx) in the forenoon.
- 2. 2. The subjects felt cooler after exposure to dim light than to bright light.
- 3. 3. Melatonin in the urine was significantly higher in bright light than in dim light at 10:30 h and at noon.
242.
243.
The d(G4) and d(C4) molecules in the single stranded state were synthesized by the phosphotriester method and purified. The full duplex of tetramer d(G4).d(C4) was prepared by expending about a month. The duplex-to-single strand transition was observed by UV-spectroscopy. A standard hypochromic effect was observed, which is different from some experimental results reported previously. 相似文献
244.
Kazunori Tanaka Takuya Kanno Yoshiko Yanagisawa Kaori Yasutake Satoshi Inoue Noriaki Hirayama Joh-E Ikeda 《PloS one》2014,9(1)
Amyotrophic lateral sclerosis (ALS) is an adult-onset motor neuron degenerative disease. Given that oxidative stress and resulting chronic neuronal inflammation are thought to be central pathogenic, anti-oxidative agents and modulators of neuronal inflammation could be potential therapies for ALS. We report here that the novel small molecular compound, 2-[mesityl(methyl)amino]-N-[4-(pyridin-2-yl)-1H-imidazol-2-yl] acetamide trihydrochloride (WN1316) selectively suppresses oxidative stress-induced cell death and neuronal inflammation in the late-stage ALS mice. WN1316 has high blood-brain-barrier permeability and water solubility, and boosts both neuronal apoptosis inhibitory protein (NAIP) and NF-E2-related factor 2 (Nrf2) which governed glutathione (GSH)-related anti-oxidation pathway protecting motor neurons against oxidative injuries. Post-onset oral administration of low dose (1–100 µg/kg/day) WN1316 in ALS(SOD1H46R) and ALS(SOD1G93A) mice resulted in sustained improved motor function and post onset survival rate. Immunohistochemical analysis revealed less DNA oxidative damage and motor neuronal inflammation as well as repression of both microgliosis and astrocytosis, concomitant down regulation of interleukin-1β and inducible nitric oxide synthase, and preservation of the motoneurons in anterior horn of lumbar spinal cord and skeletal muscle (quadriceps femoris). Thus, WN1316 would be a novel therapeutic agent for ALS. 相似文献
245.
Richard Karban Kaori Shiojiri Satomi Ishizaki William C. Wetzel Richard Y. Evans 《Proceedings. Biological sciences / The Royal Society》2013,280(1756)
The ability of many animals to recognize kin has allowed them to evolve diverse cooperative behaviours; such ability is less well studied for plants. Many plants, including Artemisia tridentata, have been found to respond to volatile cues emitted by experimentally wounded neighbours to increase levels of resistance to herbivory. We report that this communication was more effective among A. tridentata plants that were more closely related based on microsatellite markers. Plants in the field that received cues from experimentally clipped close relatives experienced less leaf herbivory over the growing season than those that received cues from clipped neighbours that were more distantly related. These results indicate that plants can respond differently to cues from kin, making it less likely that emitters will aid strangers and making it more likely that receivers will respond to cues from relatives. More effective defence adds to a growing list of favourable consequences of kin recognition for plants. 相似文献
246.
247.
Kaede Takahashi Kaori Fukushima Shiho Otagaki Kaichi Ishimoto Kanako Minami Nobuyuki Fukushima 《Journal of receptor and signal transduction research》2018,38(1):71-75
Lysophosphatidic acid (LPA) is a simple physiological lipid and exhibits a variety of cellular responses via the activation of G protein-coupled transmembrane LPA receptors (LPA receptor-1 (LPA1) to LPA6). The aim of our study was to investigate effects of LPA receptors on soft agar colony formation in colon cancer cells treated with anticancer drugs. DLD1 cells were treated with fluorouracil (5-FU) or cisplatin (CDDP) for at least six months (DLD-5FU and DLD-CDDP cells, respectively). LPAR1 gene expression was markedly elevated in DLD-5FU cells. In contrast, DLD-CDDP cells showed the high expression of LPAR6 gene. In colony formation assay, DLD-5FU cells formed markedly large-sized colonies, while no colony formation was observed in DLD1 and DLD-CDDP cells. The large-sized colonies formed in DLD-5FU cells were suppressed by LPA1 knockdown. In contrast, LPA6 knockdown increased the size of colonies. In addition, DLD-5FU cells were further treated with CDDP for three months (DLD-C-F cells). DLD-CDDP cells were also treated with 5-FU (DLD-F-C cells). DLD-C-F cells formed large-sized colonies, but not DLD-F-C cells, correlating with LPAR1 and LPAR6 gene expression levels. These results suggest that LPA1 and LPA6 may regulate the colony formation activity in DLD1 cells treated with anticancer drugs. 相似文献
248.
Hidekazu Tanaka Takahiro Yamaguchi Kae Hachiya Kazuhiro Miwa Jun Shinoda Masahide Hayashi Shinichi Ogawa Hironori Nishibori Satoshi Goshima Masayuki Matsuo 《Reports of Practical Oncology and Radiotherapy》2018,23(3):215-219
Aim
To define the optimal margin on MRI scans in the re-radiation planning of recurrent glioblastoma using methionine positron emission tomography (MET-PET).Background
It would be very useful if the optimal margin on MRI to cover the uptake area on MET-PET is known.Materials and Methods
CT, MRI, and MET-PET were performed separately over the course of 2 weeks. Among the MRI scans, we used the contrast-enhanced T1-weighted images (Gd-MRI) and T2-weighted images (T2-MRI). The Gd-MRI-based clinical target volume (CTV) (CTV-Gd) and the T2-MRI-based CTV (CTV-T2) were defined as the contrast-enhanced area on Gd-MRI and the high intensity area on T2-MRI, respectively. We defined CTV x mm (x = 5, 10, 15, 20) as x mm outside the CTV. MET-PET-based CTV (CTV-MPET) was defined as the area of accumulation of MET-PET. We calculated the sensitivity and specificity of CTV-Gd and CTV-T2 following comparison with CTV-MPET, which served as the gold standard in this study.Results
The sensitivity of CTV-T2 5 mm (98%) was significantly higher than CTV-T2 (87%), and there was no significant difference in the sensitivity between CTV-T2 5 mm and CTV T2 10, 15, or 20 mm. The sensitivity of CTV-Gd 20 mm (97%) was lower than that of CTV-T2 5 mm (98%).Conclusions
A margin of at least 5 mm around the high intensity area on T2-MRI is necessary in the target volume delineation of recurrent glioblastoma for the coverage of MET-PET findings in re-radiation therapy planning. 相似文献249.
We developed 13 polymorphic microsatellite loci of the Japanese land leech (Haemadipsa japonica; Haemadipsidea) using an Illumina MiSeq sequencing approach. A total of 42,064 nuclear DNA contigs were filtered for microsatellite motifs, among which 30,873 simple sequence repeat loci were identified. From these sequences, we selected 30 primer sets, and 13 of these loci were successfully amplified. Polymorphism of the 13 loci was tested using 16 individuals sampled from sixteen populations across Japan. The number of alleles and polymorphism information content varied from 5 to 17 and 0.335 to 0.883, respectively, and observed and expected heterozygosity values ranged from 0.143 to 0.875 and 0.349 to 0.893, respectively, indicating that these loci are polymorphic. Furthermore, we established useful multiplex PCR using these loci. The 13 microsatellite loci described in this paper are the first nuclear microsatellite markers for a land leech species. 相似文献
250.
Satoru Watanabe Hiroaki Ozawa Hiroaki Kato Kaori Nimura-Matsune Toshifumi Hirayama Fumitaka Kudo 《Bioscience, biotechnology, and biochemistry》2018,82(1):161-165
Owing to their photosynthetic capabilities, there is increasing interest in utilizing cyanobacteria to convert solar energy into biomass. 2-Deoxy-scyllo-inosose (DOI) is a valuable starting material for the benzene-free synthesis of catechol and other benzenoids. DOI synthase (DOIS) is responsible for the formation of DOI from d-glucose-6-phosphate (G6P) in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics such as neomycin and butirosin. DOI fermentation using a recombinant Escherichia coli strain has been reported, although a carbon source is necessary for high-yield DOI production. We constructed DOI-producing cyanobacteria toward carbon-free and sustainable DOI production. A DOIS gene derived from the butirosin producer strain Bacillus circulans (btrC) was introduced and expressed in the cyanobacterium Synechococcus elongatus PCC 7942. We ultimately succeeded in producing 400 mg/L of DOI in S. elongatus without using a carbon source. DOI production by cyanobacteria represents a novel and efficient approach for producing benzenoids from G6P synthesized by photosynthesis. 相似文献