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1.
There is an urgent need for the development of novel antimicrobial agents that offer effective treatment against MRSA. Using a new class of dipeptide antibiotic TAN-1057A/B as lead, we designed, synthesized and evaluated analogs of TAN-1057A/B. Several novel dihydropyrimidinone antibiotics demonstrating comparable antibiotic efficacy while possessing favorable selectivity were identified.  相似文献   
2.
The cytoplasmic androgen-binding (CAB) protein of the male rat liver has been implicated to play a role in the androgen-dependent regulation of alpha 2u-globulin synthesis. The liver of the adult male rat contains about 50 fmol of specific high-affinity androgen-binding activity per milligram of total cytosolic protein. Photoaffinity labeling with [3H]R-1881 followed by SDS-polyacrylamide gel electrophoresis and autoradiography shows that the CAB is a 31-kilodalton protein. By means of DEAE-cellulose chromatography and preparative SDS-polyacrylamide gel electrophoresis, we have purified the CAB protein to electrophoretic homogeneity and have raised polyclonal rabbit antiserum that is monospecific to this protein. In the sucrose density gradient, the antiserum reacted with the androgen-binding component of the male liver cytosol prelabeled with tritiated dihydrotestosterone. Western blot analysis of the liver cytosol showed that the antiserum recognizes only the 31-kDa androgen-binding component. Such immunoblotting also showed that unlike the young adult, the androgen-insensitive states during prepuberty and senescence are associated with a marked reduction in the hepatic concentration of the immunoreactive CAB protein. No immuno-chemical cross-reactivity between CAB and another androgen-binding component of Mr 29K (which is associated with androgen insensitivity during prepuberty and senescence) was observed. The latter finding favors the possibility that 31- and 29-kDa androgen-binding components may have distinct sequence structure.  相似文献   
3.
Antimicrobial constituents from the rhizomes of Rheum emodi   总被引:4,自引:0,他引:4  
The bioassay-guided chemical examination of the rhizomes of R. emodi resulted in the isolation of two new oxanthrone esters, revandchinone-1, revandchinone-2, a new anthraquinone ether revandchinone-3 and a new oxanthrone ether, revandchinone-4. Their structures were established based on spectroscopic and degradative evidence. Occurrence of oxanthrone ether is reported for the first time. The anti bacterial and anti fungal activity of the isolates is studied.  相似文献   
4.
The availability of sequenced genomes of human and many experimental animals necessitated the development of new technologies and powerful computational tools that are capable of exploiting these genomic data and ask intriguing questions about complex nature of biological processes. This gave impetus for developing whole genome approaches that can produce functional information of genes in the form of expression profiles and unscramble the relationships between variation in gene expression and the resulting physiological outcome. These profiles represent genetic fingerprints or catalogue of genes that characterize the cell or tissue being studied and provide a basis from which to begin an investigation of the underlying biology. Among the most powerful and versatile tools are high-density DNA microarrays to analyze the expression patterns of large numbers of genes across different tissues or within the same tissue under a variety of experimental conditions or even between species. The wide spread use of microarray technologies is generating large sets of data that is stimulating the development of better analytical tools so that functions can be predicted for novel genes. In this review, the authors discuss how these profiles are being used at various stages of the drug discovery process and help in the identification of new drug targets, predict the function of novel genes, and understand individual variability in response to drugs.  相似文献   
5.
U. R. Murty 《Genetica》1972,43(1):84-89
Upto 6 B-chromosomes occurred in natural populations of the fodder grass Iseilema laxum Hack. They were smaller than the A-chromosomes and stained darker. Although the number of B's varied in different PMC's of even the same anther presumably due to the phenomena of nondisjunction and precocious divisions, it was possible to assign a definite number to a particular plant. As seen from pachytene morphology, three types of B's were seen. More than one type can also occur in the same plant. Pairing can take place between homo-as well as heteromorphic B's resulting in bivalents. B-chromosomes in Iseilema laxum appear to have a common origin.  相似文献   
6.
The activity of initiation factors obtained from free and membrane-bound polyribosomes of liver and of transplantable H5123 hepatoma of rats was investigated by using an assay of protein synthesis in vitro in which poly (U)-directed polyphenylalanine synthesis was measured. Initiation factors of membrane-bound polyribosomes prepared by using the anionic detergent deoxycholate exhibited less activity in incorporating [14C]phenylalanyltRNA into polypetides than did initiation factors of free polyribosomes. However, when membrane-bound polyribosomes were prepared after using the non-ionic detergent Triton X-100, no significant differences in activities in polyphenylalanine synthesis were observed between the initiation factors of free and membrane-bound polyribosomes. These results suggest that Triton X-100 is preferable to deoxycholate in the isolation of of initiation factors from polyribosomes. Initiation factors, prepared by using Triton X-100, of free polyribosomes of hepatoma exhibited greater activity in the stimulation of polyphenylalanine synthesis than did the initiation factors of free or membrane-bound polyribosomes of host livers or of membrane-bound polyribosomes of hepatomas.  相似文献   
7.
8.
The study of the fluorescence of chlorophyll a offers a useful approach toward better understanding of the primary act of photosynthesis. This paper describes new measurements of the decay of chlorophyll a fluorescence in vivo, made with a considerably improved oscilloscopic-display technique. The main result is the identification of two decay periods both of the order of a few nanoseconds. Possible interpretations of this phenomenon are discussed.  相似文献   
9.
Summary In vitro andin vivo studies of the effect of irradiating pollen with different doses of X-rays were carried out inNicotiana rustica andN. tabacum. Dosages upto 9600 r were found to enhance the rate of growth of pollen tubers per unit time. Advantage was taken of this observation to overcome the incompatibility normally found in the crossN. tabacum x N. rustica as a result of the inadequate growth ofrustica pollen tubes intabacum style. Thus, whenrustica pollen exposed to 4800 r and 9600 r of X-rays were used to pollinatetabacum, fertilization resulting in the formation of viable hybrid seeds occurred. In the crossN. rustica×N. tabacum there is partial seed failure as a result of the hyperplastic development of the nucellar and endothelial cells. However, when X-rayedtabacum pollen were used in the cross, seed development registered a marked improvement. Since there is now evidence for suggesting that the contents of even those pollen tubes which do not participate in fertilization have some role to play in the development of the seed, it seems likely that radiation-induced biochemical changes in pollen may prove advantageous when conditions for seed development are abnormal as in instances of somatoplastic sterility. Besides such indirect biochemical effects, irradiation of pollen may also lead to genetic changes resulting in the inactivation of zygotic lethals. Thus, there is much scope for investigating the use of radiation to overcome inter-specific and inter-generic cross-incompatibility barriers.With 2 Figures in the Text  相似文献   
10.
The hydrodynamic parameters of the major protein fraction, viz. arachin from groundnut, alpha-globulin from sesame seed, brassin (M) from mustard seed and helianthinin from sunflower seed, have been determined in a single solvent system (0.05 M Tris-HCl buffer, pH 7.5 containing 0.5 M sodium chloride): sedimentation coefficient (s0(20,w)) and diffusion coefficient (D0(20,w)) by analytical ultracentrifugation, intrinsic viscosity [eta] by Ostwald viscometry and partial specific volume (V) by densimetry. The molecular weights (M) of the four proteins, calculated using the sedimentation-viscosity and sedimentation-diffusion coefficient methods, were found close to each other. The values have been compared with those in the literature and the reasons for discrepancies have been discussed.  相似文献   
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