全文获取类型
收费全文 | 1120篇 |
免费 | 91篇 |
出版年
2023年 | 7篇 |
2022年 | 14篇 |
2021年 | 31篇 |
2020年 | 16篇 |
2019年 | 18篇 |
2018年 | 35篇 |
2017年 | 31篇 |
2016年 | 44篇 |
2015年 | 65篇 |
2014年 | 66篇 |
2013年 | 100篇 |
2012年 | 83篇 |
2011年 | 104篇 |
2010年 | 56篇 |
2009年 | 46篇 |
2008年 | 52篇 |
2007年 | 73篇 |
2006年 | 62篇 |
2005年 | 45篇 |
2004年 | 41篇 |
2003年 | 52篇 |
2002年 | 45篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有1211条查询结果,搜索用时 437 毫秒
21.
Bozena Szulc Paulina Sosicka Dorota Maszczak-Seneczko Edyta Skurska Auhen Shauchuk Teresa Olczak Hudson H. Freeze Mariusz Olczak 《The Journal of biological chemistry》2020,295(48):16445
Nucleotide sugar transporters, encoded by the SLC35 gene family, deliver nucleotide sugars throughout the cell for various glycosyltransferase-catalyzed glycosylation reactions. GlcNAc, in the form of UDP-GlcNAc, and galactose, as UDP-Gal, are delivered into the Golgi apparatus by SLC35A3 and SLC35A2 transporters, respectively. However, although the UDP-Gal transporting activity of SLC35A2 has been clearly demonstrated, UDP-GlcNAc delivery by SLC35A3 is not fully understood. Therefore, we analyzed a panel of CHO, HEK293T, and HepG2 cell lines including WT cells, SLC35A2 knockouts, SLC35A3 knockouts, and double-knockout cells. Cells lacking SLC35A2 displayed significant changes in N- and O-glycan synthesis. However, in SLC35A3-knockout CHO cells, only limited changes were observed; GlcNAc was still incorporated into N-glycans, but complex type N-glycan branching was impaired, although UDP-GlcNAc transport into Golgi vesicles was not decreased. In SLC35A3-knockout HEK293T cells, UDP-GlcNAc transport was significantly decreased but not completely abolished. However, N-glycan branching was not impaired in these cells. In CHO and HEK293T cells, the effect of SLC35A3 deficiency on N-glycan branching was potentiated in the absence of SLC35A2. Moreover, in SLC35A3-knockout HEK293T and HepG2 cells, GlcNAc was still incorporated into O-glycans. However, in the case of HepG2 cells, no qualitative changes in N-glycans between WT and SLC35A3 knockout cells nor between SLC35A2 knockout and double-knockout cells were observed. These findings suggest that SLC35A3 may not be the primary UDP-GlcNAc transporter and/or different mechanisms of UDP-GlcNAc transport into the Golgi apparatus may exist. 相似文献
22.
Dorota Dziadkowiec Karol Kramarz Karolina Kanik Piotr Wi?niewski Antony M. Carr 《Nucleic acids research》2013,41(17):8196-8209
Previously we identified Rrp1 and Rrp2 as two proteins required for the Sfr1/Swi5-dependent branch of homologous recombination (HR) in Schizosaccharomyces pombe. Here we use a yeast two-hybrid approach to demonstrate that Rrp1 and Rrp2 can interact with each other and with Swi5, an HR mediator protein. Rrp1 and Rrp2 form co-localizing methyl methanesulphonate–induced foci in nuclei, further suggesting they function as a complex. To place the Rrp1/2 proteins more accurately within HR sub-pathways, we carried out extensive epistasis analysis between mutants defining Rrp1/2, Rad51 (recombinase), Swi5 and Rad57 (HR-mediators) plus the anti-recombinogenic helicases Srs2 and Rqh1. We confirm that Rrp1 and Rrp2 act together with Srs2 and Swi5 and independently of Rad57 and show that Rqh1 also acts independently of Rrp1/2. Mutants devoid of Srs2 are characterized by elevated recombination frequency with a concomitant increase in the percentage of conversion-type recombinants. Strains devoid of Rrp1 or Rrp2 did not show a change in HR frequency, but the number of conversion-type recombinants was increased, suggesting a possible function for Rrp1/2 with Srs2 in counteracting Rad51 activity. Our data allow us to propose a model placing Rrp1 and Rrp2 functioning together with Swi5 and Srs2 in a synthesis-dependent strand annealing HR repair pathway. 相似文献
23.
Artur Zajkowicz Małgorzata Krześniak Iwona Matuszczyk Magdalena Głowala-Kosińska Dorota Butkiewicz Marek Rusin 《Molecular biology reports》2013,40(8):5013-5026
Resveratrol is a natural compound that has been intensely studied due to its role in cancer prevention and potential as an anti-cancer therapy. Its effects include induction of apoptosis and senescence-like growth inhibition. Here, we report that two cancer cell lines (U-2 OS and A549) differ significantly in their molecular responses to resveratrol. Specifically, in U-2 OS cells, the activation of the p53 pathway is attenuated when compared to the activation in A549 cells. This attenuation is accompanied by a point mutation (458: CGA→TGA) in the PPM1D gene and overexpression of the encoded protein, which is a negative regulator of p53. Experimentally induced knockdown of PPM1D in U-2 OS cells resulted in slightly increased activation of the p53 pathway, most clearly visible as stronger phosphorylation of p53 Ser37. When treated with nutlin-3a, a non-genotoxic activator of p53, U-2 OS and A549 cells both responded with substantial activation of the p53 pathway. Nutlin-3a improved the clonogenic survival of both cell lines treated with resveratrol. This improvement was associated with lower activation of DNA-damage signaling (phosphorylation of ATM, CHK2, and histone H2AX) and higher accumulation of cells in the G1 phase of the cell cycle. Thus, the hyperactivation of p53 by nutlin-3a helps to preserve the replicative potential of cells exposed to resveratrol. 相似文献
24.
25.
The expansion of Dermacentor reticulatus to new geographical areas has been observed in several countries in Europe, including Poland and it’s neighbors. In 2011 and 2012, a total of 148 host-seeking D. reticulatus ticks were collected after flagging the vegetation in Lower Silesia, south-western Poland. Tick monitoring was conducted in mixed and deciduous forest, on meadows, in river valleys and ecotones between forested and grassy areas. The ornate dog ticks were found in 10 out of 33 sites located in five districts: Legnica, Wroclaw, ?roda ?l?ska, Lubin and Boleslawiec County. All sites where D. reticulatus ticks were found are located to the south-west of the Odra River. The greatest distance between these disconnected localities was approximately 90 km. It seems that at present the southern boundary of the range is Wroclaw district. This study indicates that D. reticulatus can be ranked as a typical element of the fauna in Lower Silesia in southwestern Poland. 相似文献
26.
Ewa Pocheć Marcelina Janik Dorota Hoja-ŁukowiczPaweł Link-Lenczowski Małgorzata PrzybyłoAnna Lityńska 《European journal of cell biology》2013
Acquisition of metastatic potential is accompanied by changes in cell surface N-glycosylation. One of the best-studied changes is increased expression of N-acetylglucosaminyltransferase V enzyme (GnT-V) and its products, β1,6-branched N-linked oligosaccharides, observed in the tumorigenesis of many cancers. In this study we demonstrate that during the transition from the vertical growth phase (VGP) (WM793 cell line) to the metastatic stage (WM1205Lu line), β1,6 glycosylation of melanoma cell surface proteins increases as a consequence of elevated expression of the GnT-V-encoding Mgat-5 gene. Treatment with swainsonine led to reduced cell motility on fibronectin in both cell lines; the effect was stronger in metastatic cells, probably due to the higher content of GlcNAc β1,6-branched glycans on the main fibronectin receptors – integrins α5β1 and α3β1. Our results show that GlcNAc β1,6 N-glycosylation of cell surface receptors, which increases with the aggressiveness of melanoma cells, is an important factor influencing melanoma cell migration. 相似文献
27.
Kamil Kokosza Jan Balzarini Dorota G. Piotrowska 《Bioorganic & medicinal chemistry》2013,21(5):1097-1108
5-Arylcarbamoyl-2-methylisoxazolidin-3-yl-3-phosphonates have been synthesised from N-methyl-C-diethoxyphosphorylnitrone and N-arylacrylamides in good yields. cis- and trans-isoxazolidine phosphonates obtained herein were evaluated for activity against a broad range of DNA and RNA viruses. None of the compounds were endowed with antiviral activity at subtoxic concentrations. Isoxazolidines having phenyl substituted with halogen (Ar = 2-F-C6H4; 3-Br-C6H4; and 4-Br-C6H4) have been found to inhibit proliferation of L1210, CEM as well as HeLa cells with IC50 in the 100–170 μM range. 相似文献
28.
Joanna Berlowska Dorota Kregiel Wojciech Ambroziak 《World journal of microbiology & biotechnology》2013,29(7):1307-1316
The adhesion of cells to solid supports is described as surface-dependent, being largely determined by the properties of the surface. In this study, ceramic surfaces modified using different organosilanes were tested for proadhesive properties using industrial brewery yeast strains in different physiological states. Eight brewing strains were tested: bottom-fermenting Saccharomyces pastorianus and top-fermenting Saccharomyces cerevisiae. To determine adhesion efficiency light microscopy, scanning electron microscopy and the fluorymetric method were used. Modification of chamotte carriers by 3-(3-anino-2-hydroxy-1-propoxy) propyldimethoxysilane and 3-(N, N-dimethyl-N-2-hydroxyethyl) ammonium propyldimethoxysilane groups increased their biomass load significantly. 相似文献
29.
30.
Comparison of Chemical Composition in Tuber aestivum Vittad. of Different Geographical Origin
下载免费PDF全文
![点击此处可从《化学与生物多样性》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dorota Hilszczańska Marta Siebyła Jakub Horak Marek Król Piotr Podsadni Piotr Steckiewicz Magdalena Bamburowicz‐Klimkowska Mirosław Szutowski Jadwiga Turło 《化学与生物多样性》2016,13(12):1617-1629
Truffles are prized and nutrition‐rich edible hypogeous fungi. The aim of this study was a comprehensive investigation of chemical composition of Burgundy truffle (Tuber aestivum Vittad .). We tried to answer the question: what is the impact of the environment on the truffle quality. To know the nutritional value of Burgundy truffle we compared lipids, proteins, saccharides, polyphenolics, flavonoids, total sterols, ergosterol, volatile flavour and aroma compounds content in fruit bodies of the fungus collected in three different geographical regions, i.e., Poland, Slovakia, and Italy. A comparison of the above mentioned compounds is especially interesting due to environmental and climatic differences among the studied geographical regions. Results revealed that fruit bodies of T. aestivum from Poland and Slovakia possessed nearly similar content of proteins, total sterols, and saccharides. The fruiting bodies from Italy contained significantly larger amounts of most of the investigated compounds. In turn, Polish specimens had higher content of lipids and polyphenolics than Slovak and Italian ones. We have found higher similarity of volatile compounds composition between Polish and Italian specimens than those of Polish and Slovak origin. 相似文献