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1.
Cancer cells frequently overexpress specific surface receptors providing tumor growth and survival which can be used for precise therapy. Targeting cancer cell receptors with protein toxins is an attractive approach widely used in contemporary experimental oncology and preclinical studies. Methods of targeted delivery of toxins to cancer cells, different drug carriers based on nanosized materials (liposomes, nanoparticles, polymers), the most promising designed light-activated toxins, as well as mechanisms of the cytotoxic action of the main natural toxins used in modern experimental oncology, are discussed in this review. The prospects of the combined therapy of tumors based on multimodal nanostructures are also discussed.  相似文献   
2.
Corynebacterium silvaticum is a newly identified animal pathogen of forest animals such as roe deer and wild boars. The species is closely related to the emerging human pathogen Corynebacterium ulcerans and the widely distributed animal pathogen Corynebacterium pseudotuberculosis. In this study, Corynebacterium silvaticum strain W25 was characterized with respect to its interaction with human cell lines. Microscopy, measurement of transepithelial electric resistance and cytotoxicity assays revealed detrimental effects of C. silvaticum to different human epithelial cell lines and to an invertebrate animal model, Galleria mellonella larvae, comparable to diphtheria toxin-secreting C. ulcerans. Furthermore, the results obtained may indicate a considerable zoonotic potential of this newly identified species.  相似文献   
3.
目的 采用免疫亲和柱净化双壳类水产中的软骨藻酸,建立高效液相色谱-三重四级杆质谱串联(LC-MS/MS)方法检测双壳类水产中的软骨藻酸,为水产品中的软骨毒素检测提供方法依据。方法 选用InfinityLab Poroshell 120 EC-C18色谱柱,以10 mmol/L甲酸铵-0.1%甲酸-甲醇为流动相,采用梯度洗脱进行分离。样品用80%甲醇水提取,上清液加入PBS缓冲液后经免疫亲和柱净化,将洗脱液氮吹至干定容后上机测定。多重态反应监测(MRM)方式检测。结果 软骨藻酸的线性范围为20.0~200 ng/ml,检出限为0.002 μg/g,回收率在75.2% ~ 85.7%之间。结论 本方法特异性强、提取效果好、无基质抑制效应,适用于双壳类水产中软骨藻酸的痕量检测。  相似文献   
4.
建立超高效液相色谱-串联质谱法同时测定小麦粉中硫脲、曲酸、噻苯咪唑、噻二唑、四环素5 种非法添加物的快速定量检测方法。样品经80%乙醇溶液-乙腈(1∶1,V/V)提取、离心、氮吹浓缩后,采用多反应监测模式进行定性、定量分析。结果表明:本方法中硫脲、曲酸、四环素在100~5 000 ng/mL、噻苯咪唑在1~50 ng/mL、噻二唑在1~50 μg/mL范围内线性关系良好,相关系数大于0.999。硫脲、曲酸、四环素检出限为25 μg/kg,定量限为50 μg/kg;噻苯咪唑检出限为0.5 μg/kg,定量限为1 μg/kg;噻二唑检出限为0.5 mg/kg,定量限为1 mg/kg。基质添加回收率范围在88.6%~102.2%之间,相对标准偏差在0.7%~5.6%之间(n=6)。该方法前处理简单、快速,可用于小麦粉中硫脲、曲酸、噻苯咪唑、噻二唑、四环素5 种非法添加物的快速测定。  相似文献   
5.
目的 初步探究肉桂醛对葡萄采后链格孢菌菌丝体生长及非寄主选择性毒素合成的影响。方法 采用扫描电镜(scanning electron microscopy, SEM)观察肉桂醛处理后链格孢菌菌丝体的形态结构; 测定处理后菌丝体脂质和麦角固醇含量, 胞外电导率、OD260值和菌丝体荧光强度; 高效液相色谱(high performance liquid chromatography, HPLC)测定处理后链格孢酚(alternariol, AOH)、交链格孢酚单甲醚(alternariol monomethyl ether, AME)含量的变化。结果 扫描电镜结果显示肉桂醛处理后链格孢菌菌丝体形态结构明显被破坏; 脂质和麦角固醇含量显著下降; 胞外电导率和OD260值以及菌丝体荧光强度显著增加; AOH、AME的含量显著下降。 结论 肉桂醛通过破坏细胞膜通透性和完整性来抑制链格孢菌菌丝体生长, 同时体内主要非寄主选择性毒素合成受到抑制。  相似文献   
6.
Mycotoxins are secondary metabolites produced by filamentous fungi that usually contaminate food products. Coffee is a natural product susceptible to mycotoxin contamination. The present study evaluates the presence of nivalenol, deoxynivalenol, T-2 and HT-2 Toxin, diacetoxyscirpenol, aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, fumonisin B1, fumonisin B2, ochratoxin A, zearalenone, enniatin A, enniatin A1, enniatin B, enniatin B1, and beauvericin in coffee samples, using liquid chromatography tandem mass spectrometry (LC-MS/MS). The results show that zearalenone was not present in any sample. In the positive samples the contents of fumonisins ranged from 58.62 to 537.45 μg/kg, emerging mycotoxins ranged from 0.10 to 3569.92 μg/kg, aflatoxins ranged from 0.25 to 13.12 μg/kg, and trichothecenes, excepting nivalenol, ranged from 5.70 to 325.68 μg/kg. Nivalenol presented the highest concentrations, from 0.40 to 25.86 mg/kg. Ochratoxin A ranged from 1.56 to 32.40 μg/kg, and five samples exceeded the maximum limit established by the European Commission.  相似文献   
7.
Theabrownins (TB) are polymeric phenolic compounds associated with the multiple bioactivities of Pu-erh tea, a post-fermented Chinese dark tea. High-TB instant Pu-erh tea was produced via a novel submerged fermentation (SF) using Aspergillus tubingensis and compared with samples produced commercially via the conventional solid-state fermentation (SSF). Viable microorganisms and microbial toxins, especially aflatoxins B1, G1, B2, G2, cyclopiazonic acid, fumonisins B1, B2, B3 and ochratoxin A, were below the detection limit in all samples. Fewer microbial metabolites were found in SF instant tea compared with the SSF teas. Based on an adult consuming 1 g of instant Pu-erh tea daily, the dietary intake of investigated elements was below the safe limits recommended by various authorities. Tasters viewed the instant tea infusions as very mild, smooth, mellow and full. This suggested that submerged fermentation using A. tubingensis offers a speedy and safe alternative to commercial production of instant Pu-erh tea.  相似文献   
8.
Protein affinity reagents (e.g., antibodies) are often used for basic research, diagnostics, separations, and disease therapy. Although a lot of “synthetic” protein affinity reagents have been developed as a cost-effective alternative to antibodies, their low biocompatibility is a considerable problem for clinical application. Lipid nanoparticles (LNP) represent a highly biocompatible drug delivery agent. However, little has been reported that LNP itself works as a protein affinity reagent in living animals. Here, LNP is engineered for binding to and neutralizing a target toxic peptide in living animals by multifunctionalization with amino acid derivatives. Multifunctionalized LNP (MF-LNP) is prepared using amino acid derivative-conjugated lipids. Optimized MF-LNP exhibits nanomolar affinity to the target toxic peptide and inhibits toxic peptide-dependent hemolysis and cytotoxicity. In addition, MF-LNP captures and neutralizes the toxic peptide after intravenous injection in the bloodstream; in addition, MF-LNP does not release the toxic peptide in the accumulated organ. These results reveal the potential of using LNP as a highly biocompatible protein affinity reagent such as an antidote.  相似文献   
9.
The Shiga toxin (Stx) family is composed of related protein toxins produced by the bacteria Shigella dysenteriae and certain pathogenic strains of E. coli. No effective therapies for Stx intoxication have been developed yet. However, inhibitors that act on the intracellular trafficking of these toxins may provide new options for the development of therapeutic strategies. This study reports the synthesis, chromatographic separation, and pharmacological evaluation of the two enantiomers of Retro‐1, a compound active against Stx and other such protein toxins. Retro‐1 works by inhibiting retrograde transport of these toxins inside cells. In vitro experiments proved that the configuration of the stereocenter at position 5 is not crucial for the activity of this compound. X‐ray diffraction data revealed (S)‐Retro‐1 to be slightly more active than (R)‐Retro‐1.  相似文献   
10.
Bacillus cereus can cause emetic and diarrheal food poisoning. It is widespread in nature and therefore, considered a major foodborne pathogen. To develop a sensitive and reliable assay for detecting enterotoxin genes (nheA, entFM, hblD, cytK) and emetic toxin (ces), specific primers each targeting one individual gene were designed. Propidium monoazide (PMA) was coupled with the developed multiplex PCR (mPCR) for the detection of viable B. cereus. The inclusivity and exclusivity of the PMA-mPCR was confirmed using a panel of 44 strains including 17 emetic and 9 enterotoxic B. cereus reference strains and 18 non-target strains. The limit of detection (LOD) without PMA treatment in pure DNA was 2 pg/reaction tube. The LOD of mPCR assay in pure heat-killed dead bacteria was 4.0 × 102 CFU/mL. Also, the LOD on the viable bacteria with or without PMA treatment was similar (3.8 × 102 CFU/mL) showing that the PMA treatment did not significantly decrease sensitivity. Finally, the newly developed PMA-mPCR successfully detected 4.8 × 103 and 3.6 × 103 CFU/g of viable B. cereus F4810/72 (emetic) and B. cereus ATCC 12480 (enterotoxic) reference strains, respectively, in food samples. Hence, this study combines PMA and mPCR to detect viable B. cereus with a wide range of toxin detection (5 toxins). Thus, the novel PMA-mPCR assay developed in this study is a rapid and efficient diagnostic tool for the monitoring of viable B. cereus in food samples and potentially other samples via appropriate DNA extraction.  相似文献   
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