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921.
Štroch Michal Karlický Václav Ilík Petr Ilíková Iva Opatíková Monika Nosek Lukáš Pospíšil Pavel Svrčková Marika Rác Marek Roudnický Pavel Zdráhal Zbyněk Špunda Vladimír Kouřil Roman 《Photosynthesis research》2022,154(1):21-40
Photosynthesis Research - The acclimation of higher plants to different light intensities is associated with a reorganization of the photosynthetic apparatus. These modifications, namely, changes... 相似文献
922.
Elizabeth Theogaraj Susan Riley Laurie Hughes Monika Maier David Kirkland 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2007,634(1-2):205-219
Ultrafine titanium dioxide is widely used in a number of commercial products including sunscreens and cosmetics. There is extensive evidence on the safety of ultrafine titanium dioxide. However, there are some published studies indicating that some forms at least may be photogenotoxic, photocatalytic and/or carcinogenic. In order to clarify the conflicting opinions on the safety of ultrafine titanium dioxide particles, the current studies were performed to investigate the photo-clastogenic potential of eight different classes of ultrafine titanium dioxide particles. The photo-clastogenicity of titanium dioxide was measured in Chinese hamster ovary (CHO) cells in the absence and presence of UV light at a dose of 750 mJ/cm2. The treatments were short (3 h) followed by a 17-h recovery and achieved concentrations that either induced approximately 50% cytotoxicity or reached 5000 μg/ml if non-cytotoxic. None of the titanium dioxide particles tested induced any increase in chromosomal aberration frequencies either in the absence or presence of UV. These studies show that ultrafine titanium dioxide particles do not exhibit photochemical genotoxicity in the model system used. 相似文献
923.
924.
Sonja Aits Jennifer Kricker Bin Liu Anne-Marie Ellegaard Saara H?m?list? Siri Tvingsholm Elisabeth Corcelle-Termeau S?ren H?gh Thomas Farkas Anna Holm Jonassen Irina Gromova Monika Mortensen Marja J??ttel? 《Autophagy》2015,11(8):1408-1424
Lysosomal membrane permeabilization (LMP) contributes to tissue involution, degenerative diseases, and cancer therapy. Its investigation has, however, been hindered by the lack of sensitive methods. Here, we characterize and validate the detection of galectin puncta at leaky lysosomes as a highly sensitive and easily manageable assay for LMP. LGALS1/galectin-1 and LGALS3/galectin-3 are best suited for this purpose due to their widespread expression, rapid translocation to leaky lysosomes and availability of high-affinity antibodies. Galectin staining marks individual leaky lysosomes early during lysosomal cell death and is useful when defining whether LMP is a primary or secondary cause of cell death. This sensitive method also reveals that cells can survive limited LMP and confirms a rapid formation of autophagic structures at the site of galectin puncta. Importantly, galectin staining detects individual leaky lysosomes also in paraffin-embedded tissues allowing us to demonstrate LMP in tumor xenografts in mice treated with cationic amphiphilic drugs and to identify a subpopulation of lysosomes that initiates LMP in involuting mouse mammary gland. The use of ectopic fluorescent galectins renders the galectin puncta assay suitable for automated screening and visualization of LMP in live cells and animals. Thus, the lysosomal galectin puncta assay opens up new possibilities to study LMP in cell death and its role in other cellular processes such as autophagy, senescence, aging, and inflammation. 相似文献
925.
926.
Polar marine ecosystems’ functioning is known to be strongly affected by the seasonality of water column production. However,
a response of benthic organisms may range from close coupling to total decoupling from seasonal variability of environmental
processes, depending on a feeding strategy. In this study, we used a multi-method approach (gut content, lipid and stable
isotope analyses) to examine trophic ecology and major food sources of a large set of Arctic sub-littoral amphipods, and to
evaluate whether their feeding strategies undergo seasonal changes. The wide range of δ15N values (5.45-12.43‰) indicates that amphipods form a trophic continuum from primary herbivores to carnivores/scavengers.
Three main feeding modes, namely scavenging/predatory, deposit-feeding/predatory and phytodetrivory, were distinguished based
on the multivariate analysis of whole fatty acid profiles. Total lipid content was low in all species and included primarily
short-term energy reserves of triacylglycerols. In general, amphipods feeding habits appeared to be independent of the seasonal
phytodetritial pulses. Low reliance on lipid reserves and lack of major changes in the trophic strategies over time suggest
that these crustaceans feed continuously, taking advantage of a variety of food sources that are available year-round in shallow
polar waters. 相似文献
927.
Zielonka J Zielonka M Sikora A Adamus J Joseph J Hardy M Ouari O Dranka BP Kalyanaraman B 《The Journal of biological chemistry》2012,287(5):2984-2995
Herein we describe a high-throughput fluorescence and HPLC-based methodology for global profiling of reactive oxygen and nitrogen species (ROS/RNS) in biological systems. The combined use of HPLC and fluorescence detection is key to successful implementation and validation of this methodology. Included here are methods to specifically detect and quantitate the products formed from interaction between the ROS/RNS species and the fluorogenic probes, as follows: superoxide using hydroethidine, peroxynitrite using boronate-based probes, nitric oxide-derived nitrosating species with 4,5-diaminofluorescein, and hydrogen peroxide and other oxidants using 10-acetyl-3,7-dihydroxyphenoxazine (Amplex® Red) with and without horseradish peroxidase, respectively. In this study, we demonstrate real-time monitoring of ROS/RNS in activated macrophages using high-throughput fluorescence and HPLC methods. This global profiling approach, simultaneous detection of multiple ROS/RNS products of fluorescent probes, developed in this study will be useful in unraveling the complex role of ROS/RNS in redox regulation, cell signaling, and cellular oxidative processes and in high-throughput screening of anti-inflammatory antioxidants. 相似文献
928.
An electrochemical approach for detection of individual single nucleotide polymorphisms (SNPs) based on nucleobase-conjugated apoferritin probe loaded with metal phosphate nanoparticles is reported. Coupling of the nucleotide-modified nanoparticle probe to the mutant sites of duplex DNA was induced by DNA polymerase I (Klenow fragment) to preserve Watson-Crick base-pairing rules. After sequential liquid hybridization of biotinylated DNA probes with mutant DNA and complementary DNA, the resulting duplex DNA helixes were captured to the surface of magnetic beads through a well known and specific biotin-streptavidin affinity binding. For signaling each of eight possible Single-nucleotide polymorphisms (SNPs), Pb, Cu, Cd and Zn phosphate-loaded apoferritin nanoparticle probes were linked to adenosine (A), cytidine (C), guanosine (G), and thymidine (T) mononucleotides, respectively. Monobase-conjugated apoferritin probes were coupled to the mutant sites of the formed duplex DNA in the presence of DNA polymerase. Electrochemical stripping analyses of the metals loaded in apoferritin nanoparticle probes provide a means for detection and quantification of mutant DNA. Each mutation captures different nucleotide-conjugated apoferritin probe and provide a distinct four-potential voltammogram, whose peak potentials reflect the identity of the mismatch. The method is sensitive enough to accurately determine AG mutation, as the most thermodynamically stable mismatch to detect, in the range of 50-600 pM. The proposed protocol provides a simple, fast, cost-effective, accurate and sensitive method for detection of SNPs. 相似文献
929.
Valovičová Z Mesárošová M Trilecová L Hrubá E Marvanová S Krčmář P Milcová A Schmuczerová J Vondráček J Machala M Topinka J Gábelová A 《Mutation research》2012,743(1-2):91-98
Differences between tissues in the expression of drug-metabolizing enzymes may substantially contribute to tissue-specificity of chemical carcinogens. To verify this hypothesis, the spontaneously immortalized human keratinocytes HaCaT were used, in order to evaluate the genotoxic potential of 7H-dibenzo[c,g]carbazole (DBC), a known hepatocarcinogen and sarcomagen, and its synthetic tissue-specific derivatives, 5,9-dimethyl-DBC (DiMeDBC) and N-methyl-DBC (N-MeDBC), which manifest specific tropism to the liver and skin, respectively. HaCaT cells mainly express cytochrome P4501A1 (CYP1A1), which is involved in metabolism of DBC and N-MeDBC, but not DiMeDBC [10]. Both DBC and the sarcomagen N-MeDBC induced significant levels of DNA strand-breaks, micronuclei, and DNA adducts followed by the phosphorylation of the p53 protein and histone H2AX in HaCaT cells. In contrast, the specific hepatocarcinogen DiMeDBC was devoid of any significant genotoxic activity in this cell line. Our study demonstrates that the absence of drug-metabolizing enzyme(s) involved in DiMeDBC metabolism may contribute substantially to the tissue-specific genotoxicity of this hepatocarcinogen. 相似文献
930.