全文获取类型
收费全文 | 2722篇 |
免费 | 130篇 |
国内免费 | 2篇 |
出版年
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 64篇 |
2020年 | 29篇 |
2019年 | 36篇 |
2018年 | 74篇 |
2017年 | 56篇 |
2016年 | 77篇 |
2015年 | 113篇 |
2014年 | 150篇 |
2013年 | 182篇 |
2012年 | 195篇 |
2011年 | 200篇 |
2010年 | 113篇 |
2009年 | 98篇 |
2008年 | 204篇 |
2007年 | 181篇 |
2006年 | 192篇 |
2005年 | 156篇 |
2004年 | 131篇 |
2003年 | 133篇 |
2002年 | 124篇 |
2001年 | 25篇 |
2000年 | 18篇 |
1999年 | 17篇 |
1998年 | 17篇 |
1997年 | 16篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 9篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1991年 | 11篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1975年 | 11篇 |
1974年 | 9篇 |
1973年 | 9篇 |
1972年 | 7篇 |
1970年 | 4篇 |
排序方式: 共有2854条查询结果,搜索用时 31 毫秒
991.
Involvement of mammalian mitochondrial glycerophosphate dehydrogenase (mGPDH, EC 1.1.99.5) in reactive oxygen species (ROS) generation was studied in brown adipose tissue mitochondria by different spectroscopic techniques. Spectrofluorometry using ROS-sensitive probes CM-H2DCFDA and Amplex Red was used to determine the glycerophosphate- or succinate-dependent ROS production in mitochondria supplemented with respiratory chain inhibitors antimycin A and myxothiazol. In case of glycerophosphate oxidation, most of the ROS originated directly from mGPDH and coenzyme Q while complex III was a typical site of ROS production in succinate oxidation. Glycerophosphate-dependent ROS production monitored by KCN-insensitive oxygen consumption was highly activated by one-electron acceptor ferricyanide, whereas succinate-dependent ROS production was unaffected. In addition, superoxide anion radical was detected as a mGPDH-related primary ROS species by fluorescent probe dihydroethidium, as well as by electron paramagnetic resonance (EPR) spectroscopy with DMPO spin trap. Altogether, the data obtained demonstrate pronounced differences in the mechanism of ROS production originating from oxidation of glycerophosphate and succinate indicating that electron transfer from mGPDH to coenzyme Q is highly prone to electron leak and superoxide generation. 相似文献
992.
Handschuh L Femiak I Kasperska A Figlerowicz M Sikorski MM 《Acta biochimica Polonica》2007,54(4):783-796
PR-10 proteins (pathogensis-related), ubiquitous within the plant kingdom, are usually encoded by multigene families. To date we have identified 10 homologous pr-10 genes in a yellow lupine cDNA library. Here, the structure and expression of two newly identified yellow lupine pr-10 genes (LlYpr10-2b and LlYpr10-2f) are presented. Many potential regulatory sites were found in both gene promoters including common ones as well as those unique for each gene. However, promoter deletion analysis in transgenic tobacco plants revealed similar patterns of reporter gene (gus) expression. Shortened fragments of both gene promoters studied caused high GUS activity in leaves (along vascular bundles), stamen stigma, anthers and pollen grains. When conjugated with longer LlYpr-10.2 promoter fragments, GUS was additionally present in petal edges. Only a long fragment of the LlYpr10-2b gene promoter caused GUS expression in the stem. In yellow lupine the pr-10.2 genes are present in all studied organs, but their level of expression depends on the stage of development and is affected by wounding, oxidative stress and salicylic acid treatment. Silencing of the Llpr-10.2b gene in 4-week-old yellow lupine plants did not lead to any visible symptoms, which suggests that the function of the silenced gene is supplemented by its close homologues, still present in the studied plants. 相似文献
993.
Paula da Fonseca-Pereira Phuong Anh Pham Joo Henrique F. Cavalcanti Rebeca P. Omena-Garcia Jessica A. S. Barros Laise Rosado-Souza Jos G. Vallarino Marek Mutwil Tamar Avin-Wittenberg Adriano Nunes-Nesi Alisdair R. Fernie Wagner L. Araújo 《The Plant journal : for cell and molecular biology》2022,109(1):196-214
994.
Kieliszek Marek Błażejak Stanisław Bzducha-Wróbel Anna Kot Anna M. 《Biological trace element research》2019,187(1):316-327
Biological Trace Element Research - This article discusses the effect of selenium in aqueous solutions on aspects of lipid and amino acid metabolism in the cell biomass of Saccharomyces cerevisiae... 相似文献
995.
Jarosz Łukasz Marek Agnieszka Grądzki Zbigniew Laskowska Ewa Kwiecień Małgorzata 《Biological trace element research》2019,187(1):258-272
Biological Trace Element Research - The aim of the study was to determine how inorganic and organic forms of zinc affect the concentrations of C-reactive protein (CRP), serum amyloid A (SAA),... 相似文献
996.
Smýkalová Iva Vrbová Miroslava Cvečková Magdalena Plačková Lenka Žukauskaitė Asta Zatloukal Marek Hrdlička Jakub Plíhalová Lucie Doležal Karel Griga Miroslav 《Plant Cell, Tissue and Organ Culture》2019,139(2):381-394
Plant Cell, Tissue and Organ Culture (PCTOC) - The biotechnological utilization (genetic transformation, gene editing) of industrial hemp (Cannabis sativa L.) has been hampered by a lack of robust... 相似文献
997.
Sahana Shivaramu Carlos E. Santo Vojtch Kapar David Bierbach Jrn Gessner Marek Rodina David Gela Martin Flajhans Sven Wuertz 《Zeitschrift fur angewandte Ichthyologie》2019,35(1):217-225
We studied the effect of intraspecific hybridization on swimming performance in sterlet, hypothesizing that such hybridization increases the performance by inducing the hybrid vigor. A total of 12 purebred and hybrid crosses were reproduced from Danube (D) and Volga (V) populations of Acipenser ruthenus. Within each cross, one group of fish was exposed to temperature challenges mimicking the temperature variation in the natural environment during summer. Temperature challenges comprised a constant increase from 19°C to 24°C and then return to 19°C within 12 hr (dT<1°C/hr), and were carried out every third day over the experimental period of 20 days. As a control, fish from each cross were kept at a constant temperature of 19°C. Critical swimming speed (Ucrit) was assessed on day 0 (29 days post hatch, dph), 10 (39 dph) and 20 (49 dph). The critical swimming speeds ranged from 5.12 cm/s (1.63 TL/s) to 16.44 cm/s (2.4 TL/s) during the experimental period (29–49 dph). There were no significant differences observed in Ucrit between repeatedly temperature challenged and control groups, indicating that the temperature challenge did not alter the swimming performance. The critical swimming speed showed positive relationship with total body length. Comparing intraspecific hybrid crosses with purebred crosses, no significant difference in swimming performance was observed. It is thus concluded that swimming performance is a family specific trait. There is no indication that intraspecific hybridization affects swimming performance nor that close‐to‐natural temperature regimes increase swimming performance. 相似文献
998.
Alexander Graf Jens Claßen Drte Solle Bernd Hitzmann Karsten Rebner Marek Hoehse 《Engineering in Life Science》2019,19(5):352-362
A new two‐dimensional fluorescence sensor system was developed for in‐line monitoring of mammalian cell cultures. Fluorescence spectroscopy allows for the detection and quantification of naturally occurring intra‐ and extracellular fluorophores in the cell broth. The fluorescence signals correlate to the cells’ current redox state and other relevant process parameters. Cell culture pretests with twelve different excitation wavelengths showed that only three wavelengths account for a vast majority of spectral variation. Accordingly, the newly developed device utilizes three high‐power LEDs as excitation sources in combination with a back‐thinned CCD‐spectrometer for fluorescence detection. This setup was first tested in a lab design of experiments study with process relevant fluorophores proving its suitability for cell culture monitoring with LOD in the μg/L range. The sensor was then integrated into a CHO‐K1 cell culture process. The acquired fluorescence spectra of several batches were evaluated using multivariate methods. The resulting batch evolution models were challenged in deviating and “golden batch” validation runs. These first tests showed that the new sensor can trace the cells’ metabolic state in a fast and reliable manner. Cellular distress is quickly detected as a deviation from the “golden batch”. 相似文献
999.
Bartlomiej Zapotoczny Filip Braet Edyta Kus Katarzyna Ginda‐Mkel Beata Klejevskaja Roberto Campagna Stefan Chlopicki Marek Szymonski 《Traffic (Copenhagen, Denmark)》2019,20(12):932-942
Fenestrae are open transmembrane pores that are a structural hallmark of healthy liver sinusoidal endothelial cells (LSECs). Their key role is the transport of solutes and macromolecular complexes between the sinusoidal lumen and the space of Disse. To date, the biochemical nature of the cytoskeleton elements that surround the fenestrae and sieve plates in LSECs remain largely elusive. Herein, we took advantage of the latest developments in atomic force imaging and super‐resolution fluorescence nanoscopy to define the organization of the supramolecular complex(es) that surround the fenestrae. Our data revealed that spectrin, together with actin, lines the inner cell membrane and provided direct structural support to the membrane‐bound pores. We conclusively demonstrated that diamide and iodoacetic acid (IAA) affect fenestrae number by destabilizing the LSEC actin‐spectrin scaffold. Furthermore, IAA induces rapid and repeatable switching between the open vs closed state of the fenestrae, indicating that the spectrin‐actin complex could play an important role in controlling the pore number. Our results suggest that spectrin functions as a key regulator in the structural preservation of the fenestrae, and as such, it might serve as a molecular target for altering transendothelial permeability. 相似文献
1000.
Michaela Helmel Martina Marchetti-Deschmann Martin Raus Andreas E. Posch Christoph Herwig Marek Šebela Günter Allmaier 《Analytical biochemistry》2015
Penicillin production during a fermentation process using industrial strains of Penicillium chrysogenum is a research topic permanently discussed since the accidental discovery of the antibiotic. Intact cell mass spectrometry (ICMS) can be a fast and novel monitoring tool for the fermentation progress during penicillin V production in a nearly real-time fashion. This method is already used for the characterization of microorganisms and the differentiation of fungal strains; therefore, the application of ICMS to samples directly harvested from a fermenter is a promising possibility to get fast information about the progress of fungal growth. After the optimization of the ICMS method to penicillin V fermentation broth samples, the obtained ICMS data were evaluated by hierarchical cluster analysis or an in-house software solution written especially for ICMS data comparison. Growth stages of a batch and fed-batch fermentation of Penicillium chrysogenum are differentiated by one of those statistical approaches. The application of two matrix-assisted laser desorption/ionization time-of-flight (MALDI–TOF) instruments in the linear positive ion mode from different vendors demonstrated the universal applicability of the developed ICMS method. The base for a fast and easy-to-use method for monitoring the fermentation progress of P. chrysogenum is created with this ICMS method developed especially for fermentation broth samples. 相似文献