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141.
142.
Katranidis A Grange W Schlesinger R Choli-Papadopoulou T Brüggemann D Hegner M Büldt G 《FEBS letters》2011,585(12):1859-1863
We show that optical tweezers are a valuable tool to study the co-translational folding of a nascent polypeptide chain at the ribosome in real-time. The aim of this study was to demonstrate that a stable and intact population of ribosomes can be tethered to polystyrene beads and that specific hook-ups to the nascent polypeptide chain by dsDNA handles, immobilized on a second bead, can be detected. A rupture force of the nascent chain in the range of 10-50 pN was measured, which demonstrates that the system is anchored to the surface in a stable and specific way. This will allow in numerous future applications to follow protein folding using much lower forces. 相似文献
143.
The biochemistry of homoterpenes--common constituents of floral and herbivore-induced plant volatile bouquets 总被引:2,自引:0,他引:2
Volatile organic compounds emitted by plants mediate a variety of interactions between plants and other organisms. The irregular acyclic homoterpenes, 4,8-dimethylnona-1,3,7-triene (DMNT) and 4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT), are among the most widespread volatiles produced by angiosperms with emissions from flowers and from vegetative tissues upon herbivore feeding. Special attention has been placed on the role of homoterpenes in attracting parasitoids and predators of herbivores and has sparked interest in engineering homoterpene formation to improve biological pest control. The biosynthesis of DMNT and TMTT proceeds in two enzymatic steps: the formation of the tertiary C15-, and C20-alcohols, (E)-nerolidol and (E,E)-geranyl linalool, respectively, catalyzed by terpene synthases, and the subsequent oxidative degradation of both alcohols by a single cytochrome P450 monooxygenase (P450). In Arabidopsis thaliana, the herbivore-induced biosynthesis of TMTT is catalyzed by the concerted activities of the (E,E)-geranyllinalool synthase, AtGES, and CYP82G1, a P450 of the so far uncharacterized plant CYP82 family. TMTT formation is in part controlled at the level of AtGES expression. Co-expression of AtGES with CYP82G1 at wound sites allows for an efficient conversion of the alcohol intermediate. The identified homoterpene biosynthesis genes in Arabidopsis and related genes from other plant species provide tools to engineer homoterpene formation and to address questions of the regulation and specific activities of homoterpenes in plant-herbivore interactions. 相似文献
144.
Lang JM Kaikobad MR Wallace M Staab MJ Horvath DL Wilding G Liu G Eickhoff JC McNeel DG Malkovsky M 《Cancer immunology, immunotherapy : CII》2011,60(10):1447-1460
Prior to the advent of VEGF-targeted therapies, renal cell carcinoma (RCC) was among the few solid tumors shown to respond
to cytokine-based therapies such as interleukin-2 (IL-2) and interferon alpha. Previous work has shown that aminobisphosphonates,
including zoledronic acid (ZA), are capable of activating human Vγ9 Vδ2 T cells in vitro, and these cells can be further expanded
with IL-2. Moreover, these Vγ9 Vδ2 T cells have cytolytic activity in vitro to multiple human tumor cell lines. In the current
report, we have conducted a pilot trial in patients with metastatic RCC, evaluating different doses of ZA in combination with
low-dose IL-2 to determine whether combining these agents can promote in vivo proliferation of Vγ9 Vδ2 T cells and elicit
an antitumor response. In 12 patients evaluated, no objective clinical responses were observed by RECIST criteria; however,
two patients experienced prolonged stable disease. A modest increase in Vγ9 Vδ2 T-cell frequency could be detected by Day
8 of therapy in four of the nine patients who received at least one cycle of therapy, but not to the magnitude anticipated
from preclinical models. Repeated administration of IL-2 and ZA resulted in both a diminished in vivo percentage of Vγ9 Vδ2
T cells as well as impaired expansion in vitro after the first cycle of therapy. These results suggest that repeated administration
of IL-2 and ZA, at the doses and schedules used in this trial, may actually inhibit the proliferative capacity of Vγ9 Vδ2
T cell in patients with metastatic RCC. 相似文献
145.
The maternally inherited obligate bacteria Wolbachia is known to infect various lepidopteran insects. However, so far only a few butterfly species harbouring this bacterium have
been thoroughly studied. The current study aims to identify the infection status of these bacteria in some of the commonly
found butterfly species in India. A total of nine butterfly species belonging to four different families were screened using
PCR with Wolbachia-specific wsp and ftsZ primers. The presence of the Wolbachia super group ‘B’ in the butterflies Red Pierrot, Talicada nyseus (Guerin) (Lepidoptera: Lycaenidae) and Blue Mormon, Papilio polymnestor Cramer (Papilionidae), is documented for the first time in India. The study also gives an account on the lifetime fecundity
and female-biased sex ratio in T. nyseus, suggesting a putative role for Wolbachia in the observed female-biased sex ratio distortion. 相似文献
146.
Lipid peroxidation is one of the consequences of environmental stress in plants and leads to the accumulation of highly toxic, reactive aldehydes. One of the processes to detoxify these aldehydes is their oxidation into carboxylic acids catalyzed by NAD(P)+-dependent ALDHs (aldehyde dehydrogenases). We investigated kinetic parameters of two Arabidopsis thaliana family 3 ALDHs, the cytosolic ALDH3H1 and the chloroplastic isoform ALDH3I1. Both enzymes had similar substrate specificity and oxidized saturated aliphatic aldehydes. Catalytic efficiencies improved with the increase of carbon chain length. Both enzymes were also able to oxidize α,β-unsaturated aldehydes, but not aromatic aldehydes. Activity of ALDH3H1 was NAD+-dependent, whereas ALDH3I1 was able to use NAD+ and NADP+. An unusual isoleucine residue within the coenzyme-binding cleft was responsible for the NAD+-dependence of ALDH3H1. Engineering the coenzyme-binding environment of ALDH3I1 elucidated the influence of the surrounding amino acids. Enzyme activities of both ALDHs were redox-sensitive. Inhibition was correlated with oxidation of both catalytic and non-catalytic cysteine residues in addition to homodimer formation. Dimerization and inactivation could be reversed by reducing agents. Mutant analysis showed that cysteine residues mediating homodimerization are located in the N-terminal region. Modelling of the protein structures revealed that the redox-sensitive cysteine residues are located at the surfaces of the subunits. 相似文献
147.
Christian F Szaszák M Friedl S Drewianka S Lorenz D Goncalves A Furkert J Vargas C Schmieder P Götz F Zühlke K Moutty M Göttert H Joshi M Reif B Haase H Morano I Grossmann S Klukovits A Verli J Gáspár R Noack C Bergmann M Kass R Hampel K Kashin D Genieser HG Herberg FW Willoughby D Cooper DM Baillie GS Houslay MD von Kries JP Zimmermann B Rosenthal W Klussmann E 《The Journal of biological chemistry》2011,286(11):9079-9096
A-kinase anchoring proteins (AKAPs) tether protein kinase A (PKA) and other signaling proteins to defined intracellular sites, thereby establishing compartmentalized cAMP signaling. AKAP-PKA interactions play key roles in various cellular processes, including the regulation of cardiac myocyte contractility. We discovered small molecules, 3,3'-diamino-4,4'-dihydroxydiphenylmethane (FMP-API-1) and its derivatives, which inhibit AKAP-PKA interactions in vitro and in cultured cardiac myocytes. The molecules bind to an allosteric site of regulatory subunits of PKA identifying a hitherto unrecognized region that controls AKAP-PKA interactions. FMP-API-1 also activates PKA. The net effect of FMP-API-1 is a selective interference with compartmentalized cAMP signaling. In cardiac myocytes, FMP-API-1 reveals a novel mechanism involved in terminating β-adrenoreceptor-induced cAMP synthesis. In addition, FMP-API-1 leads to an increase in contractility of cultured rat cardiac myocytes and intact hearts. Thus, FMP-API-1 represents not only a novel means to study compartmentalized cAMP/PKA signaling but, due to its effects on cardiac myocytes and intact hearts, provides the basis for a new concept in the treatment of chronic heart failure. 相似文献
148.
Aldehyde dehydrogenases (ALDHs) represent a protein superfamily of NAD(P)(+)-dependent enzymes that oxidize a wide range of endogenous and exogenous aliphatic and aromatic aldehydes. The Arabidopsis genome contains 14 unique ALDH sequences encoding members of nine ALDH families, including eight known families and one novel family (ALDH22) that is currently known only in plants. Here, we identify members of the ALDH gene superfamily in Arabidopsis; provide a revised, unified nomenclature for these ALDH genes; analyze the molecular relationship among Arabidopsis ALDH genes and compare them to ALDH genes from other species, including prokaryotes and mammals; and describe the role of ALDHs in cytoplasmic male sterility, plant defense and abiotic stress tolerance. 相似文献
149.
Salem Djedidi Katsuhiro Kojima Hiroko Yamaya Naoko Ohkama-Ohtsu Sonoko Dorothea Bellingrath-Kimura Izumi Watanabe Tadashi Yokoyama 《Journal of plant research》2014,127(5):585-597
The effects of inoculation with Bacillus and Azospirillum strains on growth and cesium accumulation of five plant species, Komatsuna, Amaranth, sorghum, common millet and buckwheat, grown on cesium-spiked soil were assessed for potential use in cesium remediation. Pot experiments were performed using “artificially” Cs-contaminated soil. Three treatments were applied based on Cs location in the soil. For a soil height of 15 cm in the pots, Cs was added as follows: in the top five cm to imitate no ploughing condition; in the bottom five cm simulating inverted ploughing; and uniformly distributed Cs reproducing normal plowing. Generally, inoculation of Cs-exposed plants significantly enhanced growth and tolerance to this element. Transfer factor (ratio of Cs concentration in the plant tissues to that in surrounding soil) was strongly influenced by Cs distribution, with higher values in the top-Cs treatment. Within this treatment, inoculation of Komatsuna with Bacillus and Azospirillum strains resulted in the greatest transfer factors of 6.55 and 6.68, respectively. Cesium content in the shoots was high in the Azospirillum-inoculated Komatsuna, Amaranth, and buckwheat, i.e., 1,830, 1,220, and 1,030 µg per pot, respectively (five plants were grown in each pot). Therefore, inoculation of Komatsuna and Amaranth with the strains tested here could be effective in enhancing Cs accumulation. The decrease of Cs transfer under uniform- and bottom-Cs treatments would suggest that countermeasures aiming at decreasing the transfer of Cs could rely on ploughing practices. 相似文献
150.
Dorothea Haas Hongying Gan-Schreier Claus-Dieter Langhans Alexandros Anninos Gisela Haege Peter Burgard Andreas Schulze Georg F. Hoffmann Jürgen G. Okun 《Gene》2014
Biochemical detection of inborn errors of creatine metabolism or transport relies on the analysis of three main metabolites in biological fluids: guanidinoacetate (GAA), creatine (CT) and creatinine (CTN). Unspecific clinical presentation of the diseases might be the cause that only few patients have been diagnosed so far. We describe a LC–MS/MS method allowing fast and reliable diagnosis by simultaneous quantification of GAA, CT and CTN in urine, plasma and cerebrospinal fluid (CSF) and established reference values for each material. 相似文献