全文获取类型
收费全文 | 1271篇 |
免费 | 60篇 |
专业分类
1331篇 |
出版年
2023年 | 5篇 |
2022年 | 13篇 |
2021年 | 23篇 |
2020年 | 15篇 |
2019年 | 11篇 |
2018年 | 36篇 |
2017年 | 21篇 |
2016年 | 35篇 |
2015年 | 58篇 |
2014年 | 69篇 |
2013年 | 109篇 |
2012年 | 96篇 |
2011年 | 76篇 |
2010年 | 53篇 |
2009年 | 50篇 |
2008年 | 59篇 |
2007年 | 100篇 |
2006年 | 66篇 |
2005年 | 83篇 |
2004年 | 81篇 |
2003年 | 67篇 |
2002年 | 51篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 11篇 |
1997年 | 18篇 |
1996年 | 6篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有1331条查询结果,搜索用时 15 毫秒
61.
62.
Haraguchi K Takeda S Tanaka H Nitanda T Baba M Dutschman GE Cheng YC 《Bioorganic & medicinal chemistry letters》2003,13(21):3775-3777
Compounds having methyl, vinyl, and ethynyl groups at the 4'-position of stavudine (d4T: 2',3'-didehydro-3'-deoxythymidine) were synthesized. The compounds were assayed for their ability to inhibit the replication of HIV in cell culture. The 4'-ethynyl analogue (15) was found to be more potent and less toxic than the parent compound stavudine. 相似文献
63.
Rats fed a safflower oil (alpha-linolenic acid (ALNA)-deficient) diet over the course of two generations had significantly decreased docosahexaenoic acid (22:6n-3) and increased docosapentaenoic acid (22:5n-6) contents in the major retinal phospholipids such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS) when compared with those fed a perilla oil (ALNA-sufficient) diet, but the compositions of phosphatidylinositol acyl chains were relatively unaffected. The contents of individual phospholipids in the retina were essentially the same for the two dietary groups. The activities of the rate-limiting enzymes in the de novo synthesis of PC and PE, CTP:phosphocholine cytidylyltransferase (CT), and CTP:phosphoethanolamine cytidylyltransferase (ET), respectively, were measured in the retinas excised at 5:00, 9:00, 13:00, and 17:00 h from rats adapted to a 24-h cycle with lights on from 7:00 to 19:00 h. Both enzymes exhibited significant diurnal rhythms with the lowest activities at 5:00 h and gradually increasing activities following exposure of the rats to light; the maximum activities were at 13:00 h for CT and 17:00 h for ET. The diurnal rhythms were not significantly affected by the above-mentioned diets. However, both enzyme activities at each collection time point were significantly lower in the safflower oil group than in the perilla oil group. These results suggest that retinal phospholipid turnover associated with shedding, phagocytosis, and resynthesis of the rod outer segments is limited by ALNA deficiency. 相似文献
64.
Masayuki Mori Shingo Akiyoshi Yosuke Mizuno Hisato Okuizumi Yasushi Okazaki Yoshihide Hayashizaki Masahiko Nishimura 《Mammalian genome》1998,9(9):695-709
We have applied the restriction landmark genomic scanning (RLGS) method to the SMXA recombinant inbred (RI) mouse strain
set to reveal its detailed genetic profile. A total of 663 polymorphic RLGS spot loci were identified, 576 of which were assigned
to chromosomes. Strain distribution patterns (SDPs) at 55 microsatellite marker loci were also obtained. As a result, the
total number of loci with distinct SDPs on chromosomes increased to 400. These loci were dispersed on all chromosomes, except
for the Chromosome (Chr) Y, and effectively covered the genome with an average spacing of 4 cM. The SMXA RI strain set, hereby,
would be of value for genetic study.
Received: 20 February 1998 / Accepted: 19 May 1998 相似文献
65.
Yuichi Sugahara Shingo Akiyoshi Yasushi Okazaki Yoshihide Hayashizaki Isao Tanihata 《Mammalian genome》1998,9(8):643-651
The RLGS (Restriction Landmark Genome Scanning) method was originally developed as a powerful method for enabling viewing
of thousands of restriction landmarks. It offers a tool for obtaining information about genetic loci, with a single RLGS profile
displaying approximately 2000 restriction landmarks as spots. One of the most useful applications is RLGS spot mapping, which
allows the efficient, low-cost construction of the genetic map of any organism. However, analyses of the profiles depend mainly
on human visual observation and are tedious and laborious. Although several commercially available image analyzing systems
for profile comparison have been examined, they cannot be used for the RLGS spot mapping system owing to the background characteristics
of the RLGS profiles, unsatisfactory rates of correspondence, and inefficient correction of informative genetic data. We therefore
developed a novel automatic image analysis system for RLGS spot mapping, using an original algorithm based on the binary image
transferred from the original RLGS profile. This system was employed for identifying non-polymorphic and parental strain-specific
polymorphic spots of the F1 mouse profile and yielded efficient initial screening of RLGS profiles.
Received: 5 December 1997 / Accepted: 6 April 1998 相似文献
66.
Kozaki T Kitamura S Higashihara Y Ishibashi K Noguchi H Yasukouchi A 《Journal of PHYSIOLOGICAL ANTHROPOLOGY and Applied Human Science》2005,24(2):183-186
In order to examine whether the spectral compositions of light source may affect sleep quality, sleep architecture under different color temperatures of light sources was evaluated. Seven healthy males were exposed to the light sources of different color temperatures (3000 K, 5000 K and 6700 K) for 6.5 h before sleep. The horizontal illuminance level was kept at 1000 lux. Subjects slept on a bed in near darkness (< 10 lux) after extinguishing the light, and polysomnograms recorded the sleep parameters. In the early phase of the sleep period, the amount of stage-4 sleep (S4-sleep) was significantly attenuated under the higher color temperature of 6700 K compared with the lower color temperature of 3000 K. Present findings suggest that light sources with higher color temperatures may affect sleep quality in a view that S4-sleep period is important for sleep quality. 相似文献
67.
Hino T Yokota T Ito S Nishina K Kang YS Mori S Hori S Kanda T Terasaki T Mizusawa H 《Biochemical and biophysical research communications》2006,340(1):263-267
Brain capillary endothelial cells (BCECs) play an important role in blood-brain barrier (BBB) functions and pathophysiologic mechanisms in brain ischemia and inflammation. We try to suppress gene expression in BCECs by intravenous application of small interfering RNA (siRNA). After injection of large dose siRNA with hydrodynamic technique to mouse, suppression of endogenous protein and the BBB function of BCECs was investigated. The brain-to-blood transport function of organic anion transporter 3 (OAT3) that expressed in BCECs was evaluated by Brain Efflux Index method in mouse. The siRNA could be delivered to BCECs and efficiently inhibited endogenously expressed protein of BCECs. The suppression effect of siRNA to OAT3 is enough to reduce the brain-to-blood transport of OAT3 substrate, benzylpenicillin at BBB. The in vivo siRNA-silencing method with hydrodynamic technique may be useful for the study of BBB function and gene therapy targeting BCECs. 相似文献
68.
69.
In the developing mouse embryo, leftward fluid flow on the ventral side of the node determines left–right (L-R) asymmetry. However, the mechanism by which the rotational movement of node cilia can generate a unidirectional flow remains hypothetical. Here we have addressed this question by motion and morphological analyses of the node cilia and by fluid dynamic model experiments. We found that the cilia stand, not perpendicular to the node surface, but tilted posteriorly. We further confirmed that such posterior tilt can produce leftward flow in model experiments. These results strongly suggest that L-R asymmetry is not the descendant of pre-existing L-R asymmetry within each cell but is generated de novo by combining three sources of spatial information: antero-posterior and dorso-ventral axes, and the chirality of ciliary movement. 相似文献
70.