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281.
The aerobic metabolism of benzoate in the proteobacterium Azoarcus evansii was reinvestigated. The known pathways leading to catechol or protocatechuate do not operate in this bacterium. The presumed degradation via 3-hydroxybenzoyl-coenzyme A (CoA) and gentisate could not be confirmed. The first committed step is the activation of benzoate to benzoyl-CoA by a specifically induced benzoate-CoA ligase (AMP forming). This enzyme was purified and shown to differ from an isoenzyme catalyzing the same reaction under anaerobic conditions. The second step postulated involves the hydroxylation of benzoyl-CoA to a so far unknown product by a novel benzoyl-CoA oxygenase, presumably a multicomponent enzyme system. An iron-sulfur flavoprotein, which may be a component of this system, was purified and characterized. The homodimeric enzyme had a native molecular mass of 98 kDa as determined by gel filtration and contained 0.72 mol flavin adenine dinucleotide (FAD), 10.4 to 18.4 mol of Fe, and 13.3 to 17.9 mol of acid-labile sulfur per mol of native protein, depending on the method of protein determination. This benzoate-induced enzyme catalyzed a benzoyl-CoA-, FAD-, and O2-dependent NADPH oxidation surprisingly without hydroxylation of the aromatic ring; however, H2O2 was formed. The gene (boxA, for benzoate oxidation) coding for this protein was cloned and sequenced. It coded for a protein of 46 kDa with two amino acid consensus sequences for two [4Fe-4S] centers at the N terminus. The deduced amino acid sequence showed homology with subunits of ferredoxin-NADP reductase, nitric oxide synthase, NADPH-cytochrome P450 reductase, and phenol hydroxylase. Upstream of the boxA gene, another gene, boxB, encoding a protein of 55 kDa was found. The boxB gene exhibited homology to open reading frames in various other bacteria which code for components of a putative aerobic phenylacetyl-CoA oxidizing system. The boxB gene product was one of at least five proteins induced when A. evansii was grown on benzoate.  相似文献   
282.
Three disinfectants commonly used in poultry farms (formalin, TH4+, and Virkon-S) were chosen for the present study. The effect of disinfectant concentration and the duration of exposure to these disinfectants on the survival of Escherichia coli serotypes (O114:K-, O86, O55:K39, and O86:K60) were investigated. Formalin (0.6%), TH4+ (0.06%), and Virkon (0.5%) all killed the four serotypes within 5 min of exposure. As the disinfectant concentration decreases, the length of exposure time to kill serotype increases. At 0.03%, 0.007%, and 0.03% of formalin, TH4+ and Virkon-S concentrations failed to kill the four E. coli serotypes within 360 min, respectively. An improvement of the inhibitory effect of these disinfectants occurred when added together with the inoculum instead of an established population. The influence of formalin, TH4+, and Virkon-S on the cell morphology of E. coli O55:K39 was investigated by using transmission electron microscopy. Formalin-treated cells exhibited normal cell morphology, with the exception that the treated cell was less fimbriated, and more destruction of pili increased when formalin concentrations were doubled. Cells treated with TH4+ (0.03%) showed destruction of the cell wall and cell surface membrane after 5 min. Cell filamentation occurred at 0.015% and increased with the increase of exposure time to this drug. Spheroplasts were observed only when cells were treated with 0.125% Virkon-S for 60 min, and cell lysis started to occur when 0.25% Virkon-S was applied for 15 min. Scanning electron microscope study revealed that Virkon-S at 0.03% and TH4+ at 0.007% completely prevented the adherence of E. coli O55:K39 serotype to chicken tracheal organ, whereas formalin (0.03%) disinfection minimized the adherence of E. coli cells to tracheal explants after 360 min of incubation.  相似文献   
283.
From the arial parts of Bassia muricata, two acylated flavonoid glycosides quercetin-3-O-(6"-caffeoyl)-sophoroside and quercetin-3-O-(6"-feruloyl)-sophoroside have been isolated together with two known flavonoid glycosides quercetin-3-O-sophoroside and quercetin-3,7-O-beta-diglucopyranoside, as well as four known triterpenoidal saponins, oleanolic acid-3-O-beta-glucopyranoside, chikusetsusaponin IVa, chikusetsusaponin IVa methyl ester and oleanolic acid-3,28-beta-diglucopyranoside. The structures of the isolated compounds were verified by means of MS and NMR spectral analyses.  相似文献   
284.
Static winching tests were carried out in order to determine the mechanical resistance of Maritime pine to overturning. The tested stands were selected according to podzolic soil conditions: wet Lande, characterised by a shallow ground water table and a hard pan horizon, and dry Lande, with a deeper ground water table and a hard pan absent or broken up. As this soil horizon limits the vertical growth of tree roots, anchorage resistance was investigated with regards to the presence or absence of a hard pan underneath each tree. To determine if mechanical behaviour differed within a stand, trees from inside the stand and edge trees at the border exposed to prevailing winds were also tested. The critical turning moment (TMcrit,total) at the base of the stem was positively related to the variable (H × DBH2) (H, total tree height; DBH, tree diameter). Linear regression analyses between TMcrit,total and (H × DBH2) showed that the presence of a hard pan had no significant effect on anchorage resistance in uprooted trees. Stem failure occurred for 82% of trees on dry Lande when (H × DBH2) < 1 m3. Moreover, stem failure type on dry Lande indicated that trees were better anchored. On soil with a hard pan, edge trees were found to be 20% more resistant to overturning than inner trees. Edge trees differed from inner trees in that the soil-root plate was two times larger and also possessed a larger surface area on the windward side.  相似文献   
285.
The oil of Adenanthera pavonina L. seeds was analysed by chromatographic and instrumental means. The oil was found to be rich in neutral lipids (86.2%), and low in polar lipids (13.8%). The neutral lipids consisted mainly of triacylglycerols (64.2%). Unsaturated fatty acids were found as high as 71%, while the percentage of saturated fatty acids was only 29%. GC and GC/MS analyses revealed linoleic, oleic and lignocerotic acid to be predominant among all fatty acids in the A. pavonina oil, whereas stigmasterol was the major steroid identified within this study. Subsequently, the oil was used for preparation of submicron oil-in-water (o/w) lipid emulsions. Lipid emulsions were formulated by using soybean lecithin (SL) to investigate their particle size, Zeta potential and stability at the different oil and SL ratios. The results obtained indicate possible applications of the tested oil in pharmaceutical and medical fields as drug and cosmetic active ingredient carriers.  相似文献   
286.
287.
Microsurgery is one of the highly interesting surgical procedures that can be performed using different applications and in different specialties, including plastic surgery. The endoscope is a popular instrument used in many fields, including plastic surgery. Although the operating microscope is still a must for microsurgical performance, microsurgery could be performed, depending on the experiences and facilities, by using other visual-assisting equipment. From this point of view, the authors tried to find less costly and more widespread equipment suitable for performing microsurgery that can, furthermore, be applied in special situations and indications, such as operating in an optical cavity. The authors investigated this issue with the endoscope. In this experimental project, the authors performed vascular microsurgical anastomoses of the rats' femoral vessels to create an optical cavity in a prefabricated skin retraction model in the groin area of 10 Sprague-Dawley male rats. The microsurgical anastomoses of the femoral vessels and nerves were performed easily in a reasonable time, without recorded difficulties, and with maximum physical and visual comfort for the surgeon. The authors spent a mean time of 28.1, 27.3, and 19.2 minutes for the arterial, venous, and neural anastomoses, respectively. In this group of animals, 90 percent vascular patency and 100 percent accurate neural anastomoses were recorded. The advantage the authors noted was that this new technique of operating in the field of microsurgery, with its feasibility and difficulties, would be a point of research and application for the young generations of microsurgeons.  相似文献   
288.
Atresia ani, a common genetic defect in animals, is often accompanied by urogenital defects in calves. This paper reports a case of atresia ani with diphallus and separate scrota in a calf. The calf was born with atresia ani; surgery (to open the anus) was performed 3 days after birth. No urogenital abnormalities were noticed until 4 months after birth. At that time, two separate scrota (each containing a testis) and a sac-like structure in the middle of two scrota, were visible. The gait was abnormal, with abduction of the hind limbs while walking. Additionally, the hind legs appeared wider than usual at the hip joints. Two weeks later, two peni (diphallia) was observed, each in a separate preputial sheath. The calf had a normal karyotype on cytogenetic examination. Plasma concentrations of testosterone at 5.5, 6, and 7 months of age were 3.5, 1.9, and 1.7 ng/ml, respectively. At necropsy (7 months of age), the prepuce was thick and the glans of the right penis was adhered to the prepuce. The left penis did not have a urethra or retractor penis muscles. The sac-like structure in the middle of the two scrota contained the urinary bladder and a loop of small intestine. The pubic bone had failed to fuse at the pelvic symphysis. In conclusion, this is the first reported case of atresia ani with diphallus, separate scrota, and pubic bone separation in a calf.  相似文献   
289.
In plants, Glycoside Hydrolase (GH) Family 1 -glycosidases are believed to play important roles in many diverse processes including chemical defense against herbivory, lignification, hydrolysis of cell wall-derived oligosaccharides during germination, and control of active phytohormone levels. Completion of the Arabidopsis thalianagenome sequencing project has enabled us, for the first time, to determine the total number of Family 1 members in a higher plant. Reiterative database searches revealed a multigene family of 48 members that includes eight probable pseudogenes. Manual reannotation and analysis of the entire family were undertaken to rectify existing misannotations and identify phylogenetic relationships among family members. Forty-seven members (designated BGLU1 through BGLU47) share a common evolutionary origin and were subdivided into approximately 10 subfamilies based on phylogenetic analysis and consideration of intron–exon organizations. The forty-eighth member of this family (At3g06510; sfr2) is a -glucosidase-like gene that belongs to a distinct lineage. Information pertaining to expression patterns and potential functions of Arabidopsis GH Family 1 members is presented. To determine the biological function of all family members, we intend to investigate the substrate specificity of each mature hydrolase after its heterologous expression in the Pichia pastoris expression system. To test the validity of this approach, the BGLU44-encoded hydrolase was expressed in P. pastoris and purified to homogeneity. When tested against a wide range of natural and synthetic substrates, this enzyme showed a preference for -mannosides including 1,4--D-mannooligosaccharides, suggesting that it may be involved in A. thaliana in degradation of mannans, galactomannans, or glucogalactomannans. Supporting this notion, BGLU44 shared high sequence identity and similar gene organization with tomato endosperm -mannosidase and barley seed -glucosidase/-mannosidase BGQ60.  相似文献   
290.
Enzymes, especially proteases, have become an important and indispensable part of the processes used by the modern food and feed industry to produce a large and diversified range of products for human and animal consumption. A cysteine protease, used extensively in the food industry, was purified from germinated wheat Triticum aestivum (cv. Giza 164) grains through a simple reproducible method consisting of extraction, ion exchange chromatography and gel filtration. The molecular weight of the enzyme was estimated to be 61000+/-1200-62000+/-1500 by SDS-PAGE and gel filtration. The cysteine protease had an isoelectric point and pH optimum at 4.4 and 4.0, respectively. The enzyme exhibited more activity toward azocasein than the other examined substrates with K(m) 2.8+/-0.15 mg azocasein/ml. In addition, it had a temperature optimum of 50 degrees C and based on a heat stability study 55% of its initial activity remained after preincubation of the enzyme at 50 degrees C for 30 min prior to substrate addition. All the examined metal cations inhibited the enzyme except Co(2+), Mg(2+), Mn(2+) and Li(+). The proteolytic activity of the enzyme was inhibited by thiol-specific inhibitors, whereas iodoacetate and p-hydroxymercuribenzoate caused a competitive inhibition with Ki values 6+/-0.3 mM and 21+/-1.2 microM, respectively. Soybean trypsin inhibitor had no effect on the enzyme. The enzyme activity remained almost constant for 150 days of storage at -20 degrees C. The properties of this enzyme, temperature and pH optima, substrate specificity, stability and sensitivity to inhibitors or activators, meet the prerequisites needed for food industries.  相似文献   
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