全文获取类型
收费全文 | 2240篇 |
免费 | 138篇 |
国内免费 | 1篇 |
出版年
2022年 | 18篇 |
2021年 | 37篇 |
2020年 | 19篇 |
2019年 | 16篇 |
2018年 | 30篇 |
2017年 | 28篇 |
2016年 | 49篇 |
2015年 | 67篇 |
2014年 | 70篇 |
2013年 | 168篇 |
2012年 | 101篇 |
2011年 | 119篇 |
2010年 | 81篇 |
2009年 | 73篇 |
2008年 | 102篇 |
2007年 | 118篇 |
2006年 | 101篇 |
2005年 | 117篇 |
2004年 | 106篇 |
2003年 | 105篇 |
2002年 | 119篇 |
2001年 | 58篇 |
2000年 | 57篇 |
1999年 | 72篇 |
1998年 | 25篇 |
1997年 | 23篇 |
1996年 | 18篇 |
1995年 | 25篇 |
1994年 | 23篇 |
1993年 | 22篇 |
1992年 | 31篇 |
1991年 | 30篇 |
1990年 | 33篇 |
1989年 | 27篇 |
1988年 | 36篇 |
1987年 | 33篇 |
1986年 | 36篇 |
1985年 | 22篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 16篇 |
1980年 | 16篇 |
1979年 | 15篇 |
1977年 | 7篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1970年 | 9篇 |
1969年 | 9篇 |
1968年 | 14篇 |
1967年 | 8篇 |
排序方式: 共有2379条查询结果,搜索用时 15 毫秒
171.
NRSF regulates the fetal cardiac gene program and maintains normal cardiac structure and function 总被引:1,自引:0,他引:1
172.
Yamamoto S Nakanishi O Matsui T Shinohara N Kinoshita H Lambert C Ishikawa T 《Cellular and molecular neurobiology》2003,23(2):175-185
The analgesia effects of intrathecal adenosine A1 receptor agonist, R-PIA, on the hyperalgesia and CSF-glutamate release after formalin injection into the rat paw were evaluated. R-PIA significantly and dose-dependently attenuated increases in flinching behavior, and this attenuating effect was reversed by the adenosine A1 receptor antagonist, aminophylline. Morphine blocked flinchs, however MK-801 partially abolished. The increase in CSF-glutamate release evoked by formalin stimulation was inhibited by morphine but not by either R-PIA or MK-801. These findings suggest that the intrathecal adenosine A1 receptor agonist provokes analgesic effect via the postsynaptic action independent of an effect upon spinal glutamate release. 相似文献
173.
Yamauchi S Kinoshita Y Kinoshita Y 《Bioscience, biotechnology, and biochemistry》2003,67(9):1959-1969
(R) and (S)-Aldehydes 2, which are intermediates for the synthesis of (5R) and (5S)-HETE, were respectively synthesized from the yeast-mediated reductive products, hydroxy ester 3 and cis-lactone 4, through Baeyer-Villiger oxidation with complete retention of enantiomeric excess. 相似文献
174.
Sakaguchi T Kitagawa K Ando T Murakami Y Morita Y Yamamura A Yokoyama K Tamiya E 《Biosensors & bioelectronics》2003,19(2):115-121
A biochemical oxygen demand (BOD) sensing system based on bacterial luminescence from recombinant Escherichia coli containing lux A-E genes from Vibrio fischeri has been developed. It was possible to use frozen cells of luminescent recombinants of E. coli as the bacterial reagents for measurement. Steady bioluminescence was observed during the incubation time between 90 and 150 min in the presence of a sole carbon source such as glucose, acetate, L-glutamate and BOD standard solution (GGA solution). This disposable bacterial reagent was applied to measure and detect organic pollution due to biodegradable substances in various wastewaters. The obtained values of this study showed a similar correlation with that of the conventional method for BOD determination (BOD5). Bacterial luminescence that was visualized with an imaging system using a charge coupled device (CCD) camera and a photomulti-counter demonstrated that this method could also be used for multi-sample detection of organic pollution due to biodegradable substances by using a microtiter plate. These results suggested for successful achievement of high-though-put detection of BOD in practical. 相似文献
175.
Dimethyl sulfoxide (DMSO), a water-miscible organic solvent, has been used as a cryoprotectant for cells. It is known that DMSO stabilizes the HII phase of phosphatidylethanolamine (PE) membranes rather than the Lalpha phase, while most other water-miscible organic solvents such as acetone and ethanol destabilize the HII phase. To elucidate the mechanism for this stabilizing effect of DMSO on the HII phase, we have investigated its effects on the structures and physical properties of PE membranes. X-ray diffraction data indicated that dipalmitoleoylphosphatidylethanolamine (DPOPE) membranes in H2O at 20 degrees C were in the Lalpha phase and that an Lalpha to HII phase transition occurred at X=0.060 (mole fraction of DMSO) in water/DMSO mixtures. As the DMSO concentration increased, the basis vector length of the dioleoylphosphatidylethanolamine (DOPE)/ 16 wt% tetradecane membrane and also of the DPOPE/ 16 wt% tetradecane membrane in the HII phase decreased, suggesting that the spontaneous curvature of these membranes increased. We have also investigated the effects of DMSO on the physical properties of the PE membranes, and compared them with those of acetone. As the DMSO concentration increased, the excimer to monomer fluorescence intensities of pyrene-phosphatidylcholine in the PE membranes decreased, indicating that the membrane fluidity decreased, and also the generalized polarization value of the Laurdan fluorescent probe in the DPOPE membrane increased, indicating that the polarity of the membrane interface decreased. On the other hand, acetone had the opposite effects to DMSO. The interaction free energy between the membrane surface segments and solvent increased with an increase in DMSO concentration. It decreased the amount of solvent in the membrane interface, inducing an increase in the spontaneous curvature. This can reasonably explain the effects of DMSO on the phase stability and the physical properties of the membranes. 相似文献
176.
Dynamic localization and function of Bni1p at the sites of directed growth in Saccharomyces cerevisiae 下载免费PDF全文
Ozaki-Kuroda K Yamamoto Y Nohara H Kinoshita M Fujiwara T Irie K Takai Y 《Molecular and cellular biology》2001,21(3):827-839
Formin homology (FH) proteins are implicated in cell polarization and cytokinesis through actin organization. There are two FH proteins in the yeast Saccharomyces cerevisiae, Bni1p and Bnr1p. Bni1p physically interacts with Rho family small G proteins (Rho1p and Cdc42p), actin, two actin-binding proteins (profilin and Bud6p), and a polarity protein (Spa2p). Here we analyzed the in vivo localization of Bni1p by using a time-lapse imaging system and investigated the regulatory mechanisms of Bni1p localization and function in relation to these interacting proteins. Bni1p fused with green fluorescent protein localized to the sites of cell growth throughout the cell cycle. In a small-budded cell, Bni1p moved along the bud cortex. This dynamic localization of Bni1p coincided with the apparent site of bud growth. A bni1-disrupted cell showed a defect in directed growth to the pre-bud site and to the bud tip (apical growth), causing its abnormally spherical cell shape and thick bud neck. Bni1p localization at the bud tips was absolutely dependent on Cdc42p, largely dependent on Spa2p and actin filaments, and partly dependent on Bud6p, but scarcely dependent on polarized cortical actin patches or Rho1p. These results indicate that Bni1p regulates polarized growth within the bud through its unique and dynamic pattern of localization, dependent on multiple factors, including Cdc42p, Spa2p, Bud6p, and the actin cytoskeleton. 相似文献
177.
We induced acute skeletal muscle necrosis in rats using bupivacaine hydrochloride and found that both 2,5- and 2,3-dihydroxybenzoic acid significantly increased in skeletal muscle. A single administration of dimethyl sulphoxide, a free radical scavenger, significantly lowered concentrations of 2,5- and 2,3-dihydroxybenzoic acid. These results suggest that dimethyl sulphoxide is an effective hydroxyl radical scavenger and may be useful in the treatment of myopathy. 相似文献
178.
The gene encoding activation-induced cytidine deaminase (AID), a member of the cytidine deaminase family, was isolated from a murine B cell lymphoma line, CH12F3-2, induced by combined stimulation of TGF-beta, IL-4, and CD40L. We have isolated the human orthologue of mouse AID cDNA, which has an open reading frame of 198 residues containing a conserved cytidine deaminase motif. The amino acid sequence of human AID is 92% identical to that of mouse AID. RT-PCR analysis of 15 human tissues showed that AID mRNA is expressed strongly in lymph nodes and tonsils. The complete human AID gene consisting of five exons was isolated and mapped to chromosome 12p13 by fluorescence in situ hybridization. 相似文献
179.
The threo-selective aldol condensation of (3R, 4S)-3-hydroxy-5-trityloxy-4-pentanolide, which was prepared from L-arabinose, with piperonal was applied to the stereoselective synthesis of the olivil type of lignan, (2R, 3R, 4R)-4-benzyl-4-hydroxy-3-hydroxymethyl-2-(3,4-methylenedioxyphenyl)tetrahydrofuran. 相似文献
180.
The olivil type of lignan, (2S,3R,4R)-4-benzyl-4-hydroxy - 3 - hydroxymethyl - 2 - (3,4 - methylenedioxyphenyl)tetrahydrofuran, was stereoselectively synthesized from D-xylose. 相似文献