全文获取类型
收费全文 | 2298篇 |
免费 | 111篇 |
国内免费 | 2篇 |
出版年
2022年 | 13篇 |
2021年 | 26篇 |
2020年 | 15篇 |
2019年 | 13篇 |
2018年 | 18篇 |
2017年 | 9篇 |
2016年 | 30篇 |
2015年 | 56篇 |
2014年 | 59篇 |
2013年 | 114篇 |
2012年 | 128篇 |
2011年 | 127篇 |
2010年 | 75篇 |
2009年 | 63篇 |
2008年 | 130篇 |
2007年 | 132篇 |
2006年 | 123篇 |
2005年 | 117篇 |
2004年 | 119篇 |
2003年 | 127篇 |
2002年 | 103篇 |
2001年 | 98篇 |
2000年 | 94篇 |
1999年 | 76篇 |
1998年 | 28篇 |
1997年 | 34篇 |
1996年 | 22篇 |
1995年 | 22篇 |
1994年 | 20篇 |
1993年 | 14篇 |
1992年 | 36篇 |
1991年 | 37篇 |
1990年 | 29篇 |
1989年 | 37篇 |
1988年 | 23篇 |
1987年 | 22篇 |
1986年 | 19篇 |
1985年 | 11篇 |
1984年 | 31篇 |
1983年 | 13篇 |
1982年 | 15篇 |
1981年 | 15篇 |
1977年 | 8篇 |
1975年 | 11篇 |
1974年 | 9篇 |
1973年 | 9篇 |
1972年 | 10篇 |
1971年 | 10篇 |
1968年 | 8篇 |
1967年 | 7篇 |
排序方式: 共有2411条查询结果,搜索用时 31 毫秒
101.
102.
Effects of cryopreservation methods on post-thaw motility of spermatozoa from the Japanese pearl oyster, Pinctada fucata martensii 总被引:1,自引:0,他引:1
In order to develop cryopreservation techniques for Japanese pearl oyster spermatozoa, the effects of various cryopreservation conditions on post-thaw motility were examined. Spermatozoa cryopreserved with 10% methanol (MET), dimethylformamide or dimethylacetamide plus 90% diluent comprising 80% seawater and 20% fetal bovine serum (FBS) showed higher percentages of post-thaw motility than those cryopreserved with 10% dimethylsulfoxide or glycerol. When spermatozoa were cryopreserved with various concentrations (0-20%) of MET and 100-80% diluent, 10% MET showed the highest percentages of post-thaw motility. When spermatozoa were cryopreserved with 10% MET and 90% diluent comprising various concentrations (0-100%) of FBS or Ringer solution mixed with seawater, the percentages of post-thaw motility peaked at 20% FBS or Ringer solution, and were significantly higher for 20% FBS than for 20% Ringer solution. The percentages of post-thaw motility increased with increasing dilution ratios from 2.5- to 50-fold. Spermatozoa cooled to -50 degrees C and then immersed in liquid nitrogen (LN) showed higher post-thaw motility than those cooled to -30 degrees C or -40 degrees C. When spermatozoa were cryopreserved to -50 degrees C at various cooling rates by changing the sample height above the LN surface, the post-thaw motilities of spermatozoa cooled at 10 cm (cooling rate: -21.3 degrees C/min) and 12.5 cm (-15.6 degrees C/min) from the LN surface were higher than those at 5, 7.5 or 15 cm. These results indicate that 10% MET plus 90% diluent comprising 80% seawater and 20% FBS is a suitable extender for cryopreservation of Japanese pearl oyster spermatozoa and that samples should be cooled to -50 degrees C at a cooling rate between -15 and -20 degrees C/min for efficient storage. 相似文献
103.
104.
Kimata-Ariga Y Kurisu G Kusunoki M Aoki S Sato D Kobayashi T Kita K Horii T Hase T 《Journal of biochemistry》2007,141(3):421-428
The human malaria parasite (Plasmodium falciparum) possesses a plastid-derived organelle called the apicoplast, which is believed to employ metabolisms crucial for the parasite's survival. We cloned and studied the biochemical properties of plant-type ferredoxin (Fd) and Fd-NADP+ reductase (FNR), a redox system that potentially supplies reducing power to Fd-dependent metabolic pathways in malaria parasite apicoplasts. The recombinant P. falciparum Fd and FNR proteins were produced by synthetic genes with altered codon usages preferred in Escherichia coli. The redox potential of the Fd was shown to be considerably more positive than those of leaf-type and root-type Fds from plants, which is favourable for a presumed direction of electron flow from catabolically generated NADPH to Fd in the apicoplast. The backbone structure of P. falciparum Fd, as solved by X-ray crystallography, closely resembles those of Fds from plants, and the surface-charge distribution shows several acidic regions in common with plant Fds and some basic regions unique to this Fd. P. falciparum FNR was able to transfer electrons selectively to P. falciparum Fd in a reconstituted system of NADPH-dependent cytochrome c reduction. These results indicate that an NADPH-FNR-Fd cascade is operative in the apicoplast of human malaria parasites. 相似文献
105.
Akari Nitta Kazuya Hori Isei Tanida Ayumi Igarashi Yasuyo Deyama Takashi Ueno Eiki Kominami Manabu Sugai Koji Aoki 《Biochemical and biophysical research communications》2019,508(2):521-526
Autophagy, a system for the bulk degradation of intracellular components, is essential for homeostasis and the healthy physiology and development of cells and tissues. Its deregulation is associated with human disease. Thus, methods to modulate autophagic activity are critical for analysis of its role in mammalian cells and tissues. Here we report a method to inhibit autophagy using a mutant variant of the protein ATG7, a ubiquitin E1-like enzyme essential for autophagosome formation. During autophagy, ATG7 activates the conjugation of LC3 (ATG8) with phosphatidylethanolamine (PE) and ATG12 with ATG5. Human ATG7 interactions with LC3 or ATG12 require a thioester bond involving the ATG7 cysteine residue at position 572. We generated TetOff cells expressing mutant ATG7 protein carrying a serine substitution of this critical cysteine residue (ATG7C572S). Because ATG7C572S forms stable intermediate complexes with LC3 or ATG12, its expression resulted in a strong blockage of the ATG-conjugation system and suppression of autophagosome formation. Consequently, ATG7C572S mutant protein can be used as an inhibitor of autophagy. 相似文献
106.
107.
Akihiro Kinoshita Tomoo Tamura Chiharu Aoki Tohru Nakanishi Shizuo Sobue Fujio Suzuki Kojiro Takahashi Masaharu Takigawa 《Cell biology international》1995,19(8):647-654
Endothelin (ET) receptors on chondrocytes were demonstrated using cultured rabbit costal chondrocytes. After crosslinking the receptors on the cells with 125 I-ET-1, two major bands of 43 kDa and 46 kDa were separated by SDS-PAGE. Scatchard analysis demonstrated two classes of ET receptors with Kd values of 1 × 10?10 M and 5 × 10?9 M. The numbers of high- and low- affinity receptors were 1 × 104 and 2 × 105 per cell, respectively. The binding of ET-1 to chondrocytes was increased by treatment with PTH, DBcAMP, TGF-β1, IL-1β, RA and EGF. ET-1 stimulated DNA synthesis in cultured rabbit chondrocytes. ET-1 also stimulated calcium incorporation through the cell membrane of chondrocytes. These findings indicate that ET-1 has a physiological effect on chondrocytes via its receptors on the cells. 相似文献
108.
Marcelo Massa Alexandre Moreira Renato A. Costa Marcelo R. Lima Carlos R. Thiengo Walter Q. Marquez Aaron J. Coutts Marcelo S. Aoki 《Biology of sport / Institute of Sport》2022,39(2):435
This study examined the influence of birth date, salivary testosterone [sT] concentration, sexual maturity status, and general strength on the selection process of an elite Brazilian soccer club during a 12-month period, which was a 2nd phase of a 24-month selection process. The stature, body mass, sT, sexual maturity status [Tanner scale], and hand grip strength were assessed for 143 players during 2 weeks. From these 143 players, 100 players were dismissed [DIS] and 43 players were selected to integrate the club’s under-14 squad. Following 1-year training period, the under-14 team was assembled with 9 players designated as starters [STA], and then, comparisons were conducted taking into account a group of non-starters (selected; SEL = 34 players) and STA (n = 09). The DIS, SEL, STA players, and reference population, were compared for birth distribution. A greater proportion of players was born in the first trimester in the STA [75.0%], SEL [57.1%] and DIS [50.0%] groups compared to the reference population [25.8%]. One-way ANOVA showed a higher sT for STA group [516.0 ± 129.9 pmol·L-1], compared to SEL [415.5 ± 117.9 pmol·L-1] and DIS groups [390.9 ± 84.9 pmol·L-1; p = 0.003), and Kruskall-Wallis test showed a higher gonadal development for STA compared to DIS [p = 0.001]. The current findings suggest a strong influence of birth date and biological maturation on young soccer players selection process. Soccer coaches should consider these influences when making decisions about player selection of elite youth players. 相似文献
109.
Tanaka AR Ikeda Y Abe-Dohmae S Arakawa R Sadanami K Kidera A Nakagawa S Nagase T Aoki R Kioka N Amachi T Yokoyama S Ueda K 《Biochemical and biophysical research communications》2001,283(5):1019-1025
ABCA1 has been suggested to play a key role in cellular lipid release from peripheral cells. In order to study structure-function relationship of this protein, the protein product of a full-length human ABCA1 cDNA was examined for its functions and topological orientation. The electrophoretic mobilities of human ABCA1 expressed in transfected cells increased when treated with N-glycosidase F, suggesting that ABCA1 is highly glycosylated. The ABCA1 was photoaffinity-labeled with ATP and mediated the apoA-I-dependent-release of cholesterol and phospholipid. The influenza hemagglutinin (HA) epitope was introduced into the amino-terminus (N-HA) or between the residues 207 and 208 (207-HA) of the protein. While an antibody against the C-terminus peptide of ABCA1 detected both fusion proteins, an anti-HA antibody did not react with the N-HA fusion protein. Confocal microscopy demonstrated strong cell surface signal with the anti-HA antibody of nonpermeabilized HEK293 cells expressing the 207-HA fusion protein. The results suggested that the signal peptide in the amino-terminal region is cleaved off in its mature form and that the following large hydrophilic region is exposed to outside of cells unlike previously proposed models. We found that this amino-terminal extracellular domain contains a segment homologous to the autoantigen SS-N, an epitope of Sj?gren's syndrome, and further identified that ABCA7 codes for the autoantigen SS-N. 相似文献
110.
Glutathione-dependent binding of a photoaffinity analog of agosterol A to the C-terminal half of human multidrug resistance protein 总被引:4,自引:0,他引:4
Ren XQ Furukawa T Aoki S Nakajima T Sumizawa T Haraguchi M Chen ZS Kobayashi M Akiyama S 《The Journal of biological chemistry》2001,276(25):23197-23206
MRP1 is a 190-kDa membrane glycoprotein that confers multidrug resistance (MDR) to tumor cells. MRP1 is characterized by an N-terminal transmembrane domain (TMD(0)), which is connected to a P-glycoprotein-like core region (DeltaMRP) by a cytoplasmic linker domain zero (L(0)). It has been demonstrated that GSH plays an important role in MRP1-mediated MDR. However, the mechanism by which GSH mediates MDR and the precise roles of TMD(0) and L(0) are not known. We synthesized [(125)I]11-azidophenyl agosterol A ([(125)I]azidoAG-A), a photoaffinity analog of the MDR-reversing agent, agosterol A (AG-A), to photolabel MRP1, and found that the analog photolabeled the C-proximal molecule of MRP1 (C(932-1531)) in a manner that was GSH-dependent. The photolabeling was inhibited by anticancer agents, reversing agents and leukotriene C(4). Based on photolabeling studies in the presence and absence of GSH using membrane vesicles expressing various truncated, co-expressed, and mutated MRP1s, we found that L(0) is the site on MRP1 that interacts with GSH. This study demonstrated that GSH is required for the binding of an unconjugated agent to MRP1 and suggested that GSH interacts with L(0) of MRP1. The photoanalog of AG-A will be useful for identifying the drug binding site within MRP1, and the role of GSH in transporting substrates by MRP1. 相似文献