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81.
An E. coli expression system optimized for DELLA proteins 总被引:1,自引:0,他引:1
Sun X Frearson N Kirk C Jones WT Harvey D Rakonjac J Foster T Al-Samarrai T 《Protein expression and purification》2008,58(1):168-174
The DELLA proteins are involved in regulation of plant growth in response to phytohormonal signals such as GA, ethylene, and auxin. They have become one of most challenging and active area of research due to their fundamental roles in plant biology. Here, we describe the first successful expression of the N-terminal domains of DELLA proteins of Arabidopsis thaliana and Malus domestica in Escherichia coli system which will be used to produce monoclonal antibodies for profiling protein micro-arrays. Optimizations of the cloning, expression, and purification using specific tags have been discussed. 相似文献
82.
The aim of this study was to design and evaluate of mucoadhesive gel formulations for the vaginal application of clomiphene
citrate (CLM) for local treatment of human papilloma virus (HPV) infections. Chitosan (CHI) and polycarbophil (PC) were covalently
modified using the thioglycolic acid and L-cysteine, respectively. The formation of thiol conjugates of chitosan (CHI-TG)
and polycarbophil (PC-CYS) were confirmed by FT-IR analysis and PC-CYS and CHI-TG were found to have 148.42 ± 4.16 and 41.17 ± 2.34 μmol
of thiol groups per gram of polymer, respectively. One percent CLM gels were prepared by combination of various concentrations
of PC and CHI with thiolated conjugates of these polymers. Hardness, compressibility, elasticity, adhesiveness and cohesiveness
of the gels were measured by Texture profile analysis and the vaginal mucoadhesion was investigated by mucoadhesion test.
The increasing in the amount of the thiol conjugates was found to enhance the elasticity, cohesiveness, adhesiveness and mucoadhesion
of the gel formulations but not their hardness and compressibility when compared to gels prepared using their respective parent
formulations. Slower release rate of CLM from gels was achieved when the polymer concentrations were increased in the gel
formulations. PC and its thiol conjugate were found to prolong the release of CLM longer than 70 h unlike gel formulations
prepared using CHI and its thiol conjugate which were able to release CLM up to 12 h. Stability of CLM was preserved during
the 3 month stability analysis under controlled room temperature and accelerated conditions. 相似文献
83.
84.
This study relates to a novel mediator signaling between the nervous system and the spleen following an immune challenge. Using enzyme-linked immunospot and cell proliferation assays, we found that supernatants of cultured splenocytes prepared from subcutaneously trypanosome-inoculated rats and mice spleens obtained immediately after inoculation and added to naive cells significantly stimulate interferon-gamma production and cell proliferation compared to phosphate-buffered saline-inoculated animals. This action was abrogated by surgical denervation of the spleen. Using the fluorescent differential display technology, the gene involved in this process was identified and further cloned and its sequence was mapped to chromosome 14 (GenBank accession number: EU552928). Protein expression revealed approximately 15 kDa molecule with biological activities similar to the cultured supernatants of splenocytes obtained directly from parasite-inoculated animals. Antibodies raised against the protein blocked the activities of both the protein and the supernatant and also recognized a band in the active supernatant with the same molecular mass as the protein. Furthermore, the protein was able to reactivate experimentally immunosuppressed cells by regaining their ability to proliferate, suggesting that such a nervous system-induced immune system-released activating agent (ISRAA) may have a potential therapeutic benefit in immunocompromised situations and in further understanding the mechanism for innate immunity commencement and action. 相似文献
85.
86.
Purpose The low-density lipoprotein receptor (LDLr) mediates the uptake of LDL particles enriched with cholesterol, into several
tissues. In contrast to other tissues, the brain is thought to obtain cholesterol solely by de novo synthesis, yet certain
brain regions such as the brainstem are highly enriched with the LDLr. The goal of the present study was to assess the role
of the LDLr in maintaining cholesterol concentrations in the brainstem of wildtype and LDLr knockout (LDLr−/−) mice. Cholesterol
concentrations were also measured in the cortex, which served as a reference point, due to the lower expression of the LDLr,
as compared to the brainstem. Methods LDLr−/− and wildtype mice consumed an AIN-93G diet ad libitum until 7 weeks of age. After microwaving, the cortex and anterior
brain stem were isolated for cholesterol analysis. Cholesterol was extracted into chloroform/methanol, derivatized in trimethylsilyl
chloride and measured by gas chromatography/mass spectrometry. Results Concentrations of cholesterol in the brainstem did not differ statistically between LDLr−/− (18.8 ± 1.6 mg/g wet weight brain)
and wildtype (19.1 ± 2.0). Cortical cholesterol concentrations also did not differ statistically between LDLr−/− (11.0 ± 0.4 mg/g
wet weight brain) and wildtype (11.1 ± 0.2) mice. Conclusion The LDLr is not necessary for maintaining cholesterol concentrations in the cortex or brainstem, suggesting that other mechanisms
are sufficient to maintain brain cholesterol concentrations. 相似文献
87.
Dogs demonstrate an age-related cognitive decline, which may be related to a decrease in the concentration of omega-3 polyunsaturated
fatty acids (n-3 PUFA) in the brain. Medium chain triglycerides (MCT) increase fatty acid oxidation, and it has been suggested that this
may raise brain n-3 PUFA levels by increasing mobilization of n-3 PUFA from adipose tissue to the brain. The goal of the present study was to determine whether dietary MCT would raise n-3 PUFA concentrations in the brains of aged dogs. Eight Beagle dogs were randomized to a control diet (n = 4) or an MCT (AC-1203) enriched diet (n = 4) for 2 months. The animals were then euthanized and the parietal cortex was removed for phospholipid, cholesterol and
fatty acid determinations by gas-chromatography. Dietary enrichment with MCT (AC-1203) resulted in a significant increase
in brain phospholipid and total lipid concentrations (P < 0.05). In particular, n-3 PUFA within the phospholipid, unesterified fatty acid, and total lipid fractions were elevated in AC-1203 treated subjects
as compared to controls (P < 0.05). Brain cholesterol concentrations did not differ significantly between the groups (P > 0.05). These results indicate that dietary enrichment with MCT, raises n-3 PUFA concentrations in the parietal cortex of aged dogs. 相似文献
88.
A mixed culture containing two recombinant Bacillus subtilis strains; was used to hydrolyze 1% chicken feather; both were previously transformed with late-expressed and early expressed
alkaline protease (aprE) carrying plasmids pS1 and p5.2, respectively. Proteolytic and keratinolytic activities of the mixed culture increased in
parallel with those of the culture of B. subtilis DB100 (p5.2), and both were higher than that of B. subtilis (pS1) cultures. On the other hand, data indicated that degradation of feather by the recombinant strains B. subtilis DB100 (p5.2), was greatly enhanced when using a previously optimized medium. High levels of free amino groups as well as
soluble proteins were also obtained. The concentration of amino acids was considerably increased during the fermentation process.
It was found that, the amino acids Phe, Gly and Tyr were the major amino acids liberated in the cultures initiated by both
strains. Results render these recombinant strains suitable for application in feather biodegradation large scale processes. 相似文献
89.
Khalid Mohammed Khan Momin Khan Muhammad Ali Muhammad Taha Saima Rasheed Shahnaz Perveen M. Iqbal Choudhary 《Bioorganic & medicinal chemistry》2009,17(22):7795-7801
Bis-Schiff bases 1–27 have been synthesized and their in vitro antiglycation potential has been evaluated. Compounds 21 (IC50 = 243.95 ± 4.59 μM), 20 (IC50 = 257.61 ± 5.63 μM), and 7 (IC50 = 291.14 ± 2.53 μM) showed an excellent antiglycation activity better than the standard (rutin, IC50 = 294.46 ± 1.50 μM). This study has identified a series of potential molecules as antiglycation agents. A structure–activity relationship has been studied, and all the compounds were characterized by spectroscopic techniques. 相似文献
90.
Chromatographic investigation of the octocoral Sinularia flexibilis afforded six new cembrane diterpenes, sinuladiterpenes A–F ( 1 – 6 , resp.), in addition to four known cembranolides, 11‐episinulariolide acetate, 11 ‐ dehydrosinulariolide, 11‐episinulariolide, and sinulariolide. Their structures were elucidated by spectroscopic analysis, especially 2D‐NMR and HR‐ESI‐MS. Compound 2 exhibited significant in vitro cytotoxic activity against human colon adenocarcinoma (WiDr) cell line. 相似文献