全文获取类型
收费全文 | 2945篇 |
免费 | 183篇 |
专业分类
3128篇 |
出版年
2023年 | 6篇 |
2022年 | 22篇 |
2021年 | 33篇 |
2020年 | 14篇 |
2019年 | 20篇 |
2018年 | 42篇 |
2017年 | 29篇 |
2016年 | 62篇 |
2015年 | 102篇 |
2014年 | 98篇 |
2013年 | 160篇 |
2012年 | 182篇 |
2011年 | 199篇 |
2010年 | 115篇 |
2009年 | 111篇 |
2008年 | 188篇 |
2007年 | 179篇 |
2006年 | 163篇 |
2005年 | 178篇 |
2004年 | 160篇 |
2003年 | 175篇 |
2002年 | 160篇 |
2001年 | 57篇 |
2000年 | 51篇 |
1999年 | 48篇 |
1998年 | 44篇 |
1997年 | 34篇 |
1996年 | 45篇 |
1995年 | 42篇 |
1994年 | 15篇 |
1993年 | 29篇 |
1992年 | 47篇 |
1991年 | 41篇 |
1990年 | 26篇 |
1989年 | 36篇 |
1988年 | 23篇 |
1987年 | 11篇 |
1986年 | 22篇 |
1985年 | 14篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1979年 | 12篇 |
1978年 | 7篇 |
1970年 | 6篇 |
1969年 | 10篇 |
1968年 | 5篇 |
1967年 | 6篇 |
排序方式: 共有3128条查询结果,搜索用时 0 毫秒
991.
Yasuyuki Matoba Naomi Tanaka Masafumi Noda Fumiko Higashikawa Takanori Kumagai Masanori Sugiyama 《Proteins》2013,81(11):2052-2058
Tannin acylhydrolase (EC 3.1.1.20) referred commonly as tannase catalyzes the hydrolysis of the galloyl ester bond of tannins to release gallic acid. Although the enzyme is useful for various industries, the tertiary structure is not yet determined. In this study, we determined the crystal structure of tannase produced by Lactobacillus plantarum. The tannase structure belongs to a member of α/β‐hydrolase superfamily with an additional “lid” domain. A glycerol molecule derived from cryoprotectant solution was accommodated into the tannase active site. The binding manner of glycerol to tannase seems to be similar to that of the galloyl moiety in the substrate. Proteins 2013; 81:2052–2058. © 2013 Wiley Periodicals, Inc. 相似文献
992.
993.
994.
Periodic patterns of biochemical systems determine the function, behavior, and fate of eukaryotic cells. The cascades of mitogen-activated protein (MAP) kinases play crucial roles in a diverse range of cell function, and recent reports indicate that oscillation of extracellular signal-regulated kinase (ERK) activity is observed following stimulation by some growth factors. In the current report, we provide evidence that ERK and c-Jun N-terminal kinase, but not p38 MAP kinase, are activated periodically in response to endoplasmic reticulum stress. When activity of MAP kinases is evaluated, their oscillatory property should be considered carefully, especially under stress conditions. 相似文献
995.
996.
The physicochemical and biological properties of the new branched cyclomaltooligosaccharides (cyclodextrins; CDs), 2-O-α-d-galactosyl-cyclomaltohexaose (2-O-α-d-galactosyl-α-cyclodextrin, 2-Gal-αCD) and 2-O-α-d-galactosyl-cyclomaltoheptaose (2-O-α-d-galactosyl-β-cyclodextrin, 2-Gal-βCD), were investigated. The formation of inclusion complexes of 2-Gal-CDs with various kinds of guest compounds (clofibrate, cholesterol, cholecalciferol, digitoxin, digitoxigenin, and prostaglandin A1) was examined by a solubility method, and the results were compared with those of non-branched CDs and other 6-O-glycosyl-CDs such as 6-O-α-d-galactosyl-CDs, 6-O-α-d-glucosyl-CDs, and 6-O-α-maltosyl-CDs. The inclusion abilities of 2-Gal-αCD for clofibrate and prostaglandin A1, and 2-Gal-βCD for clofibrate, cholecalciferol, cholesterol, and digitoxigenin were markedly weaker than those of non-branched CD and other 6-O-glycosyl-CDs in each series, probably because of a steric hindrance caused by the α-(1→2)-galactoside linkage. The hemolytic activities of 2-Gal-CDs on human erythrocytes were the lowest among each CD series, and the compounds showed negligible cytotoxicity towards Caco-2 cells up to at least 100 mM. 相似文献
997.
Gradient formation and signaling ranges of secreted proteins are crucial problems to understand how morphogens work for positional information and patterning in animal development. Yet, extracellular behaviors of secreted signaling molecules remain unexplored compared to their downstream pathways inside the cell. Recent advances in bioimaging make it possible to directly visualize morphogen molecules, and this simple strategy has, at least partly, succeeded in uncovering molecular behaviors of morphogens, such as Wnt (wingless-type MMTV integration site family member) and BMP (bone morphogenetic protein) as well as secreted Wnt binding proteins, sFRPs (secreted Frizzled-related proteins), in embryonic tissues. Here, we review the regulation of Wnt signaling by sFRPs, focusing on extracellular regulation of Wnt ligands in comparison with other morphogens. We also discuss evolutionary aspects with comprehensive syntenic and phylogenetic information about vertebrate sfrp genes. We newly annotated several sfrp genes including sfrp2-like 1 (sfrp2l1) in frogs and fishes and crescent in mammals. 相似文献
998.
Godo Toshinari Hashimoto Toshimasa Nakata Masashi Miyoshi Kazumitsu 《In vitro cellular & developmental biology. Plant》2020,56(2):230-235
In Vitro Cellular & Developmental Biology - Plant - We examined the effects of culture conditions, namely, illumination, temperature and the addition of 6-benzylaminopurine (BAP) to the... 相似文献
999.
Miyuki T. Nakata Mao Nakao Asuka Denda Yusuke Onoda Haruko Ueda Taku Demura 《Plant Biotechnology》2020,37(4):471
The mechanical strength of a plant stem (a load-bearing organ) helps the plant resist drooping, buckling and fracturing. We previously proposed a method for quickly evaluating the stiffness of an inflorescence stem in the model plant Arabidopsis thaliana based on measuring its natural frequency in a free-vibration test. However, the relationship between the stiffness and flexural rigidity of inflorescence stems was unclear. Here, we compared our previously described free-vibration test with the three-point bending test, the most popular method for calculating the flexural rigidity of A. thaliana stems, and examined the extent to which the results were correlated. Finally, to expand the application range, we present an example of a modified free-vibration test. Our results provide a reference for improving estimates of the flexural rigidity of A. thaliana inflorescence stems. 相似文献
1000.
Muta Naoki Umezawa Yu Yamaguchi Akira Suzaki Hirokazu Wada Minoru Nakata Hideaki Kawamoto Kazuaki Matsuoka Kazumi 《Limnology》2020,21(3):341-356
Limnology - In the seasonally hypoxic semi-enclosed Omura Bay, Japan, regression equations estimating year-round nutrient [NO3 + NO2, NH4, PO4, Si(OH)4] concentrations in pore water... 相似文献