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21.
Ulrich Dobramysl Iris Katharina Jarsch Yoshiko Inoue Hanae Shimo Benjamin Richier Jonathan R. Gadsby Julia Mason Alicja Szaapak Pantelis Savvas Ioannou Guilherme Pereira Correia Astrid Walrant Richard Butler Edouard Hannezo Benjamin D. Simons Jennifer L. Gallop 《The Journal of cell biology》2021,220(4)
Assemblies of actin and its regulators underlie the dynamic morphology of all eukaryotic cells. To understand how actin regulatory proteins work together to generate actin-rich structures such as filopodia, we analyzed the localization of diverse actin regulators within filopodia in Drosophila embryos and in a complementary in vitro system of filopodia-like structures (FLSs). We found that the composition of the regulatory protein complex where actin is incorporated (the filopodial tip complex) is remarkably heterogeneous both in vivo and in vitro. Our data reveal that different pairs of proteins correlate with each other and with actin bundle length, suggesting the presence of functional subcomplexes. This is consistent with a theoretical framework where three or more redundant subcomplexes join the tip complex stochastically, with any two being sufficient to drive filopodia formation. We provide an explanation for the observed heterogeneity and suggest that a mechanism based on multiple components allows stereotypical filopodial dynamics to arise from diverse upstream signaling pathways. 相似文献
22.
Minarowska A Gacko M Karwowska A Minarowski Ł 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2008,46(1):23-38
A literature survey was performed of human cathepsin D gene, cathepsin D biosynthesis, posttranslatory modifications, transport within the cell, substrate specificity and catalytic effect. Methods used to determine the activity and level of this proteinase as well as its role in the biochemistry and pathobiochemistry of cells, tissues and organs were considered. 相似文献
23.
Dagmara Otto-Ślusarczyk Wojciech Graboń Magdalena Mielczarek-Puta Alicja Chrzanowska 《Biochemistry and Biophysics Reports》2021
Leflunomide (LFN) is a well-known immunomodulatory and anti-inflammatory prodrug of teriflunomide (TFN). Due to pyrimidine synthesis inhibition TFN also exhibits potent anticancer effect. Because, there is the strict coupling between the pyrimidine synthesis and the mitochondrial respiratory chain, the oxygen level could modify the cytostatic TNF effect.The aim of the study was to evaluate the cytostatic effect of pharmacologically achievable teriflunomide (TFN) concentrations at physiological oxygen levels, i.e. 1% hypoxia and 10% tissue normoxia compared to 21%oxygen level occurred in routine cell culture environment.The TFN effect was evaluated using TB, MTT and FITC Annexin tests for human primary (SW480) and metastatic (SW620) colon cancer cell lines at various oxygen levels.We demonstrated significant differences between proliferation, survival and apoptosis at 1, 10 and 21% oxygen in primary and metastatic colon cancer cell lines (SW480, SW620) under TFN treatment. The cytostatic TFN effect was more pronounced at hypoxia compared to tissue and atmospheric normoxia in both cancer cell lines, however metastatic cells were more resistant to antiproliferative and proapoptotic TFN action. The early apoptosis was predominant in physiological oxygen tension while in atmospheric normoxia the late apoptosis was induced.Our findings showed that anticancer TFN effect is more strong in physiological oxygen compared to atmospheric normoxia. It suggests that results obtained from in vitro studies could be underestimated. Thus, it gives assumption for future comprehensive studies at real oxygen environment involving TNF use in combination with other antitumor agents affecting oxygen-dependent pyrimidine synthesis. 相似文献
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We compare the chromosomal 28S and 5S rDNA patterns of the spined loach C. taenia (2n = 48) from an exclusively diploid population and from a diploid–polyploid population using 28S and 5S rDNA probe preparation
and labelling, and fluorescence in situ hybridization (FISH). The 5S rDNA was located in two to three chromosome pairs, and separated from the 28S loci for the males
and one female (F1) from the diploid population. Loaches from a diploid–polyploid population, and one female (F2) from the
diploid population were characterized by at least one chromosome pair with 5S and 28S overlapping signals. The fishes differed
mainly in their number of 28S rDNA loci, located on 3–6 chromosomes. All individuals from both populations were characterized
by one acrocentric chromosome bearing a 28S rDNA signal on the telomeres of its long arm. The number of major ribosomal DNA
in the karyotype of C. taenia by FISH was always higher than the number of Ag-NORs. Our data confirm the extensive polymorphism of NORs in both populations,
as already has been observed in closely related Cobitis species, and less polymorphic 5S rDNA pattern. However, this preliminary result highlights the need for a wider scale study. 相似文献
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Summary The cytokinin isomers, 1- and 9-isopentenyladenine, are very active inhibitors of cell division in the protonema of the moss Ceratodon purpureus. They also abolish the N6-isopentenyladenine-induced stimulation of cell divisions in this material whereas they are inactive on the induction of gametophore buds in moss protonemata by cytokinins.This work was supported by the Polish Academy of Sciences within the project 09.3.1. 相似文献
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Alicja Kosakowska Marcin Nedzi Janusz Pempkowiak 《Plant Physiology and Biochemistry》2007,45(5):365-370
Iron is an essential element to marine biota. Different types of dissolved organic matter (DOM), such as humic substances have impacts on the marine coastal waters iron chemistry. The aim of the study was to examine how the presence of humic substances (both aquatic and sedimentary) may affect iron bioavailability to the bloom-forming cyanobacterium Microcystis aeruginosa Kutzing incubated on standard and modified mineral BG-11 media. The final iron concentrations in the growth media ranged from 0.1 to 100microM. The results demonstrate that both the growth rate and the concentration of chlorophyll a in cultures of M. aeruginosa are limited by insufficient (<10microM) Fe concentrations. The addition of aquatic humic substances in the presence of iron in concentrations <0.1microM increased the optical density 25-fold, and the production of chlorophyll a 15-fold as compared with the cultures exposed to iron only at the same concentration. Sedimentary humic acids in the presence of iron at a concentration of 10microM reduced the growth and production of chlorophyll a by 50% as compared to the cultures exposed to iron only at the same concentration. Possible mechanisms of humic substances - metal ion - alga interactions are discussed. It is suggested that aquatic humic substances could be of great importance in the formation of cyanobacteria blooms. 相似文献
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