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71.
72.
Tariq MA Soedipe A Ramesh G Wu H Zhang Y Shishodia S Gridley DS Pourmand N Jejelowo O 《Molecular and cellular biochemistry》2011,349(1-2):213-218
The space radiation environment consists of trapped particle radiation, solar particle radiation, and galactic cosmic radiation (GCR), in which protons are the most abundant particle type. During missions to the moon or to Mars, the constant exposure to GCR and occasional exposure to particles emitted from solar particle events (SPE) are major health concerns for astronauts. Therefore, in order to determine health risks during space missions, an understanding of cellular responses to proton exposure is of primary importance. The expression of DNA repair genes in response to ionizing radiation (X-rays and gamma rays) has been studied, but data on DNA repair in response to protons is lacking. Using qPCR analysis, we investigated changes in gene expression induced by positively charged particles (protons) in four categories (0, 0.1, 1.0, and 2.0 Gy) in nine different DNA repair genes isolated from the testes of irradiated mice. DNA repair genes were selected on the basis of their known functions. These genes include ERCC1 (5' incision subunit, DNA strand break repair), ERCC2/NER (opening DNA around the damage, Nucleotide Excision Repair), XRCC1 (5' incision subunit, DNA strand break repair), XRCC3 (DNA break and cross-link repair), XPA (binds damaged DNA in preincision complex), XPC (damage recognition), ATA or ATM (activates checkpoint signaling upon double strand breaks), MLH1 (post-replicative DNA mismatch repair), and PARP1 (base excision repair). Our results demonstrate that ERCC1, PARP1, and XPA genes showed no change at 0.1 Gy radiation, up-regulation at 1.0 Gy radiation (1.09 fold, 7.32 fold, 0.75 fold, respectively), and a remarkable increase in gene expression at 2.0 Gy radiation (4.83 fold, 57.58 fold and 87.58 fold, respectively). Expression of other genes, including ATM and XRCC3, was unchanged at 0.1 and 1.0 Gy radiation but showed up-regulation at 2.0 Gy radiation (2.64 fold and 2.86 fold, respectively). We were unable to detect gene expression for the remaining four genes (XPC, ERCC2, XRCC1, and MLH1) in either the experimental or control animals. 相似文献
73.
74.
Mahmoud S. El-Tarabany Akram A. El-Tarabany Mostafa A. Atta 《Biological Rhythm Research》2019,50(2):245-254
Understanding the seasonal patterns of estrus cycle in caprine is crucial to develop the efficient breeding plans in the subtropics. Thus, the aim of the current research was to evaluate the effects of breeding season on hormonal profile and blood biochemical indices at different stages of estrus cycle in normal breeding or out-of-season breeding in goats. Forty-four Baladi goats were monitored for a period of eight months (July–February). Baladi goats exhibit a normal seasonal breeding (NS) at midsummer and continue through the autumn season (68%), with a considerable percentage of females having estrus signs during out-of-season (OS) period (32%). At the mid and late luteal phases of estrus cycles, the NS breeding group had significantly higher serum progesterone level than that reported in the OS group (p = 0.013 and 0.039, respectively). At the estrus and late luteal phases of estrus cycles, the NS breeding group had significantly higher serum β-estradiol level than that reported in the OS group (p = 0.022 and 0.001, respectively). Compared to the OS group, the NS breeding group had significantly higher serum cholesterol at the mid and late luteal phases of estrus cycle (p = 0.001 and 0.016, respectively), and higher serum glucose level in the early luteal phase of the cycle (p = 0.009). In conclusion, the NS breeding goats had superior progesterone (mid-luteal and late luteal phases) and estradiol (estrus and late luteal phases) profiles than that reported in the OS group. This may indicate specific approaches to maintain the breeding efficiency of goats during the out-of-season period. 相似文献
75.
Chargui N Haouas N Gorcii M Akrout Messaidi F Zribi M Babba H 《Parasite (Paris, France)》2007,14(3):247-251
An epidemiological study of canine leishmaniasis (CanL) was carried out in nine districts of Sfax, in the southern central part of Tunisia. Sera from 250 dogs were tested by two serological methods: the indirect immunofluorescence antibody test and the counter-immunoelectrophoresis. Seven to eight months later, before the next season of transmission, seropositive dogs from the first test were re-examined and a second sampling was performed. Infection status was assessed by serology and by other methods. PCR, in vitro culture and direct examination were applied on blood and other samples (bone marrow, liver, lymph node, spleen and cutaneous biopsies). The seroprevalence of the infection in dogs was 6%. Infection was then confirmed by at least one other method. The PCR is the method which agreed most with serology, all seropositive dogs were found PCR-positive. The sensitivity of the direct examination and the culture was only 33% and 55% respectively as compared with serology. A similar value of seroprevalence has been observed previously in Sousse, in the northern central part of Tunisia. The present report suggests a significant increase of CanL in the Sfax area and confirms that the disease is continuing to move southwards in Tunisia. 相似文献
76.
Extraction and precipitation of chitosan from cell wall of zygomycetes fungi by dilute sulfuric acid
A new method was developed in this work for extraction of chitosan from the zygomycetes cell wall. It is based on the temperature-dependent solubility of chitosan in dilute sulfuric acid. Chitin is soluble in neither cold nor hot dilute sulfuric acid. Similarly chitosan is not soluble at room temperature but is dissolved in 1% H 2SO 4 at 121 degrees C within 20 min. The new method was developed to measure the chitosan content of the biomass and cell wall. The procedures were investigated by measuring phosphate, protein, ash, glucuronic acid, and degree of acetylation. The cell wall derivatives of fungus Rhizomucor pusillus were then examined by this new method. The results indicated 8% of the biomass as chitosan. After treatment with NaOH, the alkali-insoluble material (AIM) contained 45.3% chitosan. Treatment of AIM with acetic acid resulted in 16.5% acetic-acid-soluble material (AcSM) and 79.0% alkali- and acid-insoluble material (AAIM). AcSM is usually cited as pure chitosan, but the new method shows major impurities by, for example, phosphate. Furthermore, AAIM is usually considered to be the chitosan-free fraction, whereas the new method shows more than 76% of the chitosan present in AIM is found in AAIM. It might indicate the inability of acetic acid to separate chitosan from the cell wall. 相似文献
77.
Wu S Avila-Sakar A Kim J Booth DS Greenberg CH Rossi A Liao M Li X Alian A Griner SL Juge N Yu Y Mergel CM Chaparro-Riggers J Strop P Tampé R Edwards RH Stroud RM Craik CS Cheng Y 《Structure (London, England : 1993)》2012,20(4):582-592
In spite of its recent achievements, the technique of single particle electron cryomicroscopy (cryoEM) has not been widely used to study proteins smaller than 100 kDa, although it is a highly desirable application of this technique. One fundamental limitation is that images of small proteins embedded in vitreous ice do not contain adequate features for accurate image alignment. We describe a general strategy to overcome this limitation by selecting a fragment antigen binding (Fab) to form a stable and rigid complex with a target protein, thus providing a defined feature for accurate image alignment. Using this approach, we determined a three-dimensional structure of an ~65 kDa protein by single particle cryoEM. Because Fabs can be readily generated against a wide range of proteins by phage display, this approach is generally applicable to study many small proteins by single particle cryoEM. 相似文献
78.
We have previously demonstrated that a slight increase in intracellular superoxide (O2*-) anion confers resistance to death stimuli. Using pharmacological and molecular approaches to manipulate intracellular O2*-, here we report that an increase in intracellular O2*- anion induces Na+/H+ exchanger 1 (NHE-1) gene promoter activity resulting in increased NHE-1 protein expression, which strongly correlates with the resistance of cells to death stimuli. In contrast, exposure to exogenous hydrogen peroxide suppressed NHE-1 promoter activity and gene expression, and increased cell sensitivity to death triggers. Furthermore, the increase in cell sensitivity to death upon downregulation of NHE-1 gene expression correlates with reduced capacity of cells to recover from an acid load, while survival upon overexpression of NHE-1 appears independent of its pump activity. These findings indicate that NHE-1 is a redox-regulated gene, and provide a novel intracellular target for the redox control of cell death sensitivity. 相似文献
79.
Barbara C. Figueiredo Akram A. Da'dara Sergio C. Oliveira Patrick J. Skelly 《PLoS pathogens》2015,11(12)
Schistosoma mansoni is a blood fluke parasite that causes schistosomiasis, a debilitating disease of global public health importance. These relatively large parasites are able to survive prolonged periods in the human vasculature without inducing stable blood clots around them. We show here that the intravascular life stages (schistosomula and adult males and females) can all promote significant plasminogen (PLMG) activation in the presence of tissue plasminogen activator (tPA). This results in the generation of the potent fibrinolytic agent plasmin which could degrade blood clots forming around the worms in vivo. We demonstrate that S. mansoni enolase (SmEno) is a host-interactive tegumental enzyme that, in recombinant form, can bind PLMG and promote its activation. Like classical members of the enolase protein family, SmEno can catalyze the interconversion of 2-phospho-D-glycerate (2-PGA) and phosphoenolpyruvate (PEP). The enzyme has maximal activity at pH 7.5, requires Mg2+ for optimal activity and can be inhibited by NaF but not mefloquin. Suppressing expression of the SmEno gene significantly diminishes enolase mRNA levels, protein levels and surface enzyme activity but, surprisingly, does not affect the ability of the worms to promote PLMG activation. Thus, while SmEno can enhance PLMG activation, our analysis suggests that it is not the only contributor to the parasite’s ability to perform this function. We show that the worms possess several other PLMG-binding proteins in addition to SmEno and these may have a greater importance in schistosome-driven PLMG activation. 相似文献
80.
Jalil Noroozi Masoud Minaei Sina Khalvati Akram Kaveh Hanieh Nafisi Behnaz Nazari Golshan Zare Ernst Vitek Karl Hülber Gerald M. Schneeweiss 《Diversity & distributions》2023,29(2):244-253