全文获取类型
收费全文 | 5217篇 |
免费 | 329篇 |
出版年
2022年 | 30篇 |
2021年 | 79篇 |
2020年 | 50篇 |
2019年 | 57篇 |
2018年 | 88篇 |
2017年 | 76篇 |
2016年 | 111篇 |
2015年 | 168篇 |
2014年 | 170篇 |
2013年 | 319篇 |
2012年 | 283篇 |
2011年 | 274篇 |
2010年 | 184篇 |
2009年 | 189篇 |
2008年 | 295篇 |
2007年 | 252篇 |
2006年 | 236篇 |
2005年 | 251篇 |
2004年 | 257篇 |
2003年 | 227篇 |
2002年 | 222篇 |
2001年 | 154篇 |
2000年 | 151篇 |
1999年 | 129篇 |
1998年 | 63篇 |
1997年 | 54篇 |
1996年 | 55篇 |
1995年 | 58篇 |
1994年 | 54篇 |
1993年 | 34篇 |
1992年 | 98篇 |
1991年 | 78篇 |
1990年 | 71篇 |
1989年 | 70篇 |
1988年 | 61篇 |
1987年 | 60篇 |
1986年 | 65篇 |
1985年 | 56篇 |
1984年 | 55篇 |
1983年 | 46篇 |
1982年 | 21篇 |
1981年 | 22篇 |
1980年 | 23篇 |
1979年 | 24篇 |
1978年 | 28篇 |
1977年 | 22篇 |
1976年 | 18篇 |
1975年 | 22篇 |
1973年 | 17篇 |
1970年 | 15篇 |
排序方式: 共有5546条查询结果,搜索用时 15 毫秒
301.
302.
Makoto Nakabayashi Naoki Shibata Emi Ishido-Nakai Mayumi Kanagawa Yota Iio Hirofumi Komori Yasufumi Ueda Noriko Nakagawa Seiki Kuramitsu Yoshiki Higuchi 《Extremophiles : life under extreme conditions》2016,20(3):275-282
TTHA0829 from Thermus thermophilus HB8 has a molecular mass of 22,754 Da and is composed of 210 amino acid residues. The expression of TTHA0829 is remarkably elevated in the latter half of logarithmic growth phase. TTHA0829 can form either a tetrameric or dimeric structure, and main-chain folding provides an N-terminal cystathionine-β-synthase (CBS) domain and a C-terminal aspartate-kinase chorismate-mutase tyrA (ACT) domain. Both CBS and ACT are regulatory domains to which a small ligand molecule can bind. The CBS domain is found in proteins from organisms belonging to all kingdoms and is observed frequently as two or four tandem copies. This domain is considered as a small intracellular module with a regulatory function and is typically found adjacent to the active (or functional) site of several enzymes and integral membrane proteins. The ACT domain comprises four β-strands and two α-helices in a βαββαβ motif typical of intracellular small molecule binding domains that help control metabolism, solute transport and signal transduction. We discuss the possible role of TTHA0829 based on its structure and expression pattern. The results imply that TTHA0829 acts as a cell-stress sensor or a metabolite acceptor. 相似文献
303.
Yasuo Oowatari Tetsuro Ogawa Takuya Katsube Kiyohisa Iinuma Hisae Yoshitomi Ming Gao 《Bioscience, biotechnology, and biochemistry》2016,80(8):1594-1601
Hypertrophy of adipocytes in obese adipose tissues causes metabolic abnormality by adipocytokine dysregulation, which promotes type 2 diabetes mellitus, hypertension, and dyslipidemia. We investigated the effects of wasabi (Wasabia japonica Matsum) leaf extracts on metabolic abnormalities in SHRSP.Z-Leprfa/IzmDmcr rats (SHRSP/ZF), which are a model of metabolic syndrome. Male SHRSP/ZF rats aged 7 weeks were divided into two groups: control and wasabi leaf extract (WLE) groups, which received water or oral treatment with 4 g/kg/day WLE for 6 weeks. WLE improved the body weight gain and high blood pressure in SHRSP/ZF rats, and the plasma triglyceride levels were significantly lower in the WLE group. Adipocyte hypertrophy was markedly prevented in adipose tissue. The expression of PPARγ and subsequent downstream genes was suppressed in the WLE group adipose tissues. Our data suggest that WLE inhibits adipose hypertrophy by suppressing PPARγ expression in adipose tissue and stimulating the AMPK activity by increased adiponectin. 相似文献
304.
Takuya Tomita Andreas Matouschek 《Protein science : a publication of the Protein Society》2019,28(7):1222-1232
Proteins in the cell have to be eliminated once their function is no longer desired or they become damaged. Most regulated protein degradation is achieved by a large enzymatic complex called the proteasome. Many proteasome substrates are targeted for degradation by the covalent attachment of ubiquitin molecules. Ubiquitinated proteins can be bound by the proteasome, but for proteolysis to occur the proteasome needs to find a disordered tail somewhere in the target at which it initiates degradation. The initiation step contributes to the specificity of proteasomal degradation. Here, we review how the proteasome selects initiation sites within its substrates and discuss how the initiation step affects physiological processes. 相似文献
305.
Yu Kitadate David J. Jörg Moe Tokue Ayumi Maruyama Rie Ichikawa Soken Tsuchiya Eri Segi-Nishida Toshinori Nakagawa Aya Uchida Chiharu Kimura-Yoshida Seiya Mizuno Fumihiro Sugiyama Takuya Azami Masatsugu Ema Chiyo Noda Satoru Kobayashi Isao Matsuo Yoshiakira Kanai Shosei Yoshida 《Cell Stem Cell》2019,24(1):79-92.e6
306.
307.
308.
Analysis of terminal sugar moieties and species-specificities of acrosome reaction-inducing substance in Xenopus (ARISX) 总被引:1,自引:1,他引:0
Ueda Y Imaizumi C Kubo H Sato K Fukami Y Iwao Y 《Development, growth & differentiation》2007,49(7):591-601
The acrosome reaction of Xenopus sperm is triggered by the acrosome reaction-inducing substance in Xenopus (ARISX), an oviductal pars recta-derived, sugar-rich substance decorated on the entire surface of the vitelline envelope (VE) during ovulation. Here we addressed the functional importance of the sugar moiety in ARISX. Among various lectins examined, soybean agglutinin and Dolichos biflorus agglutinin were shown to abolish the acrosome reaction-inducing activity of ARISX present in pars recta extract or on the VE, indicating the importance of the terminal alpha-N-acetylgalactosamine residue for the function of ARISX. Consistently, the acrosome reaction-inducing activity was not affected by proteinase K digestion, in spite of the simultaneous shift of ARISX to a smaller molecular weight. Indirect immunofluorescence microscopic examinations showed that ARISX was distributed as two types of structures on VE; thick fiber-like materials and thin filamentous materials, and that a new structure appeared on the fertilization envelope instead of the thin filamentous materials. Sperm from several amphibian species were subjected to an in vitro assay during induction of the acrosome reaction with ARISX. The resulting limited population of sperm from a non-Xenopus species underwent acrosome reaction, implying a weak species-specificity of ARISX. 相似文献
309.
Morita Y Araki H Sugimoto T Takeuchi K Yamane T Maeda T Yamamoto Y Nishi K Asano M Shirahama-Noda K Nishimura M Uzu T Hara-Nishimura I Koya D Kashiwagi A Ohkubo I 《FEBS letters》2007,581(7):1417-1424
Legumain/asparaginyl endopeptidase (EC 3.4.22.34) is a novel cysteine protease that is abundantly expressed in the late endosomes and lysosomes of renal proximal tubular cells. Recently, emerging evidence has indicated that legumain might play an important role in control of extracellular matrix turnover in various pathological conditions such as tumor growth/metastasis and progression of atherosclerosis. We initially found that purified legumain can directly degrade fibronectin, one of the main components of the extracellular matrix, in vitro. Therefore, we examined the effect of legumain on fibronectin degradation in cultured mouse renal proximal tubular cells. Fibronectin processing can be inhibited by chloroquine, an inhibitor of lysosomal degradation, and can be enhanced by the overexpression of legumain, indicating that fibronectin degradation occurs in the presence of legumain in lysosomes from renal proximal tubular cells. Furthermore, in legumain-deficient mice, unilateral ureteral obstruction (UUO)-induced renal interstitial protein accumulation of fibronectin and renal interstitial fibrosis were markedly enhanced. These findings indicate that legumain might have an important role in extracellular matrix remodeling via the degradation of fibronectin in renal proximal tubular cells. 相似文献
310.
We identified the causal genetic variation for the difference in the thoracic trident pigmentation intensity between two wild-derived strains of Drosophila melanogaster. It was found to be the difference in expression level of ebony, which codes for an enzyme in the melanin-synthesis pathway and has pleiotropic effects on vision and behavior. 相似文献