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71.
In this paper we report on the molecular cloning, sequencing and partially characterisation of a lectin from bulb of the Chinese
medicinal plant Zephyranthes grandiflora. The full-length cDNA of Z. grandiflora bulb lectin (ZGBL) consisted of 986 bp and contained a 576 bp ORF encoding a 191 amino acid protein. Bioinformatics analysis
results clearly indicate that ZGBL belongs to the monocot mannose-binding lectin family, which contains 3 putative mannose-binding
sites per subunit. RT-PCR analysis results indicate that ZGBL is constitutively expressed in all the tested tissue types including root, bulb, leaf and flower. Interestingly, ZGBL is
more closely related to the Orchidaceae rather than the Amaryllidaceae family on molecular evolution. 相似文献
72.
Production of chitinase from bacteria has distinct advantages over fungi, due to the formation of mycelia of fungi in the
later phase of fermentation. A novel chitinase-producing bacterial strain XJ-01 was isolated from the Yulu fishing field of
Changsha, Hunan province, China, by enrichment and spread-plate technique, sequentially. Physicochemical characterization
and 16S rRNA sequencing revealed that strain XJ-01 belongs to Serratia marcescens. By optimizing the fermentation condition based on L9(34) orthogonal experimental design, a maximal chitinase activity up to 15.36 U/ml was attained by that stain under the condition:
0.5% (NH4)2SO4 as the nitrogen source, 0.75% colloidal chitin as the carbon source, temperature of 32°C, time of 32 h and pH 8.0. 相似文献
73.
链霉菌C-3662产生的纤溶活性蛋白酶的纯化与理化性质 总被引:10,自引:0,他引:10
从链霉菌 C- 3662发酵上清液中 ,通过硫酸铵沉淀 ,CM- Sepharose Fast Flow和 Phenyl-Sepharose Fast Flow等层析色谱 ,分离纯化得到了具有纤溶活性的蛋白酶 CGW- 3,反向 HPLC鉴定纯度为 90 % ;每立升发酵上清液可得到 8mg纯品 ,活性回收率 46% ,CGW- 3为一单肽链蛋白 ,分子量 2 2 72 1 ,对丝氨酸蛋白酶抑制剂 PMSF敏感 ,对 EDTA不敏感 ;其 N端 1 5个氨基酸的顺序为 VVGGTRAAQGEFPFM,与微生物来源的胰蛋白酶类丝氨酸蛋白酶有较高的同源性 . CGW- 3的等电点 p I9.0 ,纤溶活性的最适 p H为 7.5~ 8.0 ,对温度比较敏感 .CGW- 3不仅具有直接降解纤维蛋白作用 ,而且能够激活纤溶酶原 相似文献
74.
Isolation and characterization of a biosurfactant‐producing Fusarium sp. BS‐8 from oil contaminated soil 下载免费PDF全文
Muneer A. Qazi Tayyaba Kanwal Muniba Jadoon Safia Ahmed Nighat Fatima 《Biotechnology progress》2014,30(5):1065-1075
This study reports characterization of a biosurfactant‐producing fungal isolate from oil contaminated soil of Missa Keswal oil field, Pakistan. It was identified as Fusarium sp. BS‐8 on the basis of macroscopic and microscopic morphology, and 18S rDNA gene sequence homology. The biosurfactant‐producing capability of the fungal isolates was screened using oil displacement activity, emulsification index assay, and surface tension (SFT) measurement. The optimization of operational parameters and culture conditions resulted in maximum biosurfactant production using 9% (v/v) inoculum at 30°C, pH 7.0, using sucrose and yeast extract, as carbon and nitrogen sources, respectively. A C:N ratio of 0.9:0.1 (w/w) was found to be optimum for growth and biosurfactant production. At optimal conditions, it attained lowest SFT (i.e., 32 mN m?1) with a critical micelle concentration of ≥ 1.2 mg mL?1. During 5 L shake flask fermentation experiments, the biosurfactant productivity was 1.21 g L?1 pure biosurfactant having significant emulsifying index (E24, 70%) and oil‐displacing activity (16 mm). Thin layer chromatography and Fourier transform infrared spectrometric analyses indicated a lipopeptide type of the biosurfactant. The Fusarium sp. BS‐8 has substantial potential of biosurfactant production, yet it needs to be fully characterized with possibility of relatively new class of biosurfactants. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1065–1075, 2014 相似文献
75.
Azuaga AI Woodruff ND Conejero-Lara F Cox VF Smith RA Dobson CM 《Protein science : a publication of the Protein Society》1999,8(2):443-446
Proteolytic studies have enabled two of the three putative domains of the fibrinolytic protein streptokinase to be isolated and characterized (Conejero-Lara F et al., 1996, Protein Sci 5:2583-2591). The N-terminal domain, however, could not be isolated in these experiments because of its susceptibility to proteolytic cleavage. To complete the biophysical characterization of the domain structure of streptokinase we have overexpressed, purified, and characterized the N-terminal region of the protein, residues 1-146. The results show this is cooperatively folded with secondary structure content and overall stability closely similar to those of the equivalent region in the intact protein. 相似文献
76.
Cheong Na Eun Choi Yeon Ok Lee Kyun Oh Kim Woe Yeon Jung Bae Gyo Chi Yong Hun Jeong Jin Sook Kim Kanghwa Cho Moo Je Lee Sang Yeol 《Plant molecular biology》1999,40(5):825-834
A cDNA (C2C-Prx) corresponding to a 2Cys-peroxiredoxin (2Cys-Prx) was isolated from a leaf cDNA library of Chinese cabbage. The predicted amino acid sequence of C2C-Prx has 2 conserved cysteines and several peptide domains present in most of the 2Cys-Prx subfamily members. It shows the highest sequence homology to the 2Cys-Prx enzymes of spinach (88%) and Arabidopsis (86%). Southern analysis using the cDNA insert of C2C-Prx revealed that it consists of a small multigene family in Chinese cabbage genome. RNA blot analysis showed that the gene was predominantly expressed in the leaf tissue of Chinese cabbage seedlings, but the mRNA was generally expressed in most tissues of mature plant, except roots. The expression of C2C-Prx was slightly induced by treatment with H2O2 (100M) or Fe3+/O2/DTT oxidation system, but not by ABA (50 M) or GA3 (10 M). The C2C-Prx is encoded as a preprotein of 273 amino acids containing a putative chloroplast-targeting signal of 65 amino acids at its N-terminus. The N-terminally truncated recombinant protein (C2C-Prx) migrates as a dimer in a non-reducing SDS-polyacrylamide gel and as a monomer in a reducing condition. The C2C-Prx shows no immuno cross-reactivity to antiserum of the yeast thiol-specific antioxidant protein, and vice versa. The C2C-Prx prevents the inactivation of glutamine synthetase and the DNA cleavage in the metal-catalyzed oxidation system. In the yeast thioredoxin system containing thioredoxin reductase, thioredoxin, and NADPH, the C2C-Prx exhibits peroxidase activity on H2O2. 相似文献
77.
A comparative study of various procedures for tryptophanyl peptide bond cleavage by BNPS-skatole [2-(2-nitrophenyl)-3-methyl-3-bromoindolenine] was carried out on native and on reduced and alkylated bovine -lactoglobulin (BLG). The reaction yield and the composition of the derived products were studied in acetic acid, trifluoroacetic acid (TFA), and ethanol/TFA. For BNPS-skatole removal, extraction by water or ethyl ether was compared with dialysis and gel filtration. The three expected peptides (1–19, 20–61, 62–162) and incomplete cleaved fragments (1–61, 20–162) were separated and characterized by electrophoresis, reverse-phase high-performance liquid chromatography, and mass spectrometry. The highest hydrolysis yield (67.4%) occurred with native BLG cleaved in 88% acetic acid at 47°C for 60 min. Subsequent water extraction and gel filtration led to total recovery of the material, but reagent elimination was only quantitative after gel filtration. Cleavage specificity was ensured by mass spectrometry and the amino acid composition of peptides 1–19 and 62–162. The chemical side reactions identified are discussed. 相似文献
78.
A systematic study of the characterization for racemic species of 4-hydroxy-2-pyrrolidone was undertaken. The melting point phase diagram of (R)- and (S)-4-hydroxy-2-pyrrolidone was determined by differential scanning calorimetry. The ternary phase diagram of (R)- and (S)-4-hydroxy-2-pyrrolidone with isopropanol was constructed at 15, 20, 25, and 35 degrees C. The crystalline nature of 4-hydroxy-2-pyrrolidone racemate was also characterized by means of comparison of solid-state FTIR spectra and powder X-ray diffraction patterns of the racemic mixture with those of one of the enantiomers. It is shown that (+/-)-4-hydroxy-2-pyrrolidone is a racemic conglomerate. The enthalpies of fusion of (R)-4-hydroxy-2-pyrrolidone and (+/-)-4-hydroxy-2-pyrrolidone and entropy of mixing of (R)- and (S)-4-hydroxy-2-pyrrolidone were calculated using the thermodynamic data. The solubility and supersolubility diagrams of (R)- and (S)-4-hydroxy-2-pyrrolidone in isopropanol were determined over a temperature range of 4-35 degrees C. The optical resolution of (+/-)-4-hydroxy-2-pyrrolidone was successfully achieved by preferential crystallization. 相似文献
79.
Fashui H 《Biological trace element research》2004,97(3):279-288
Photosystem II (PSII) particles were purified from Eu3+-treated spinach and studied by spectroscopy. The results showed that electron transport rate of PS II was accelerated by
Eu3+ treating, that violet shift of the PSII Soret band or Q-band was 6 nm or 2 nm for the ultraviolet-visible (UV-Vis) spectrum,
that the violet shift of the PSII fluorescence emission peak was 9 nm for fluorescence emission spectrum, that the PSII Signal
II’s of low-temperature electron paramagnetic resonance (EPR) spectrum was intensified under light, and that the PSII CD spectrum
was similar to that of control. It is suggested that Eu3+ might bind to the PSII reaction center complex and enhance the electron transport rate of PSII CD; however, Eu3+ treatment does not change the configuration of the PSII reaction center complex. 相似文献
80.
Yoon-Jeong?Lee Jae-Ho?Kim Ha-Kun?Kim Jong-Soo?LeeEmail author 《Biotechnology and Bioprocess Engineering》2004,9(1):17-22
A bacterial strain WJ-98 found to produce active extracellular keratinase was isolated from the soil of a poultry factory.
It was identified asParacoccus sp. based on its 16S rRNA sequence analysis, morphological and physiological characteristics. The optimal culture conditions
for the production of keratinase byParacoccus sp. WJ-98 were investigated. The optimal medium composition for keratinase production was determined to be 1.0% keratin,
0.05% urea and NaCl, 0.03% K2HPO4, 0.04% KH2PO4, and 0.01% MgCl2·6H2O. Optimal initial pH and temperature for the production of keratinase were 7.5 and 37°C, respectively. The maximum keratinase
production of 90 U/mL was reached after 84 h of cultivation under the optimal culturing conditions. The keratinase fromParacoccus sp. WJ-98 was partially purified from a culture broth by using ammonium sulfate precipitation, ion-exchange chromatography
on DEAE-cellulose, followed by gel filtration chromatography on Sephadex G-75. Optimum pH and temperature for the enzyme reaction
were pH 6.8 and 50°C, respectively and the enzymes were stable in the pH range from 6.0 to 8.0 and below 50°C. The enzyme
activity was significantly inhibited by EDTA, Zn2+ and Hg2+. Inquiry into the characteristics of keratinase production from these bacteria may yield useful agricultural feed processing
applications. 相似文献