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91.
Summary Nitrogen indole protection of the -methyltryptophan side-chain residue is important for avoiding undesired side reactions during peptide synthesis. Of great importance is the choice of a side-chain protecting group for orthogonal peptide synthesis and its stability under a variety of chemical conditions required for synthesis of the four isomers of this unusual amino acid. We report here the successful use of the mesitylenesulfonyl (Mts) protecting group for -methyltryptophan in the synthesis of melanotropin and CCK peptide analogues and the ready cleavage of this protecting group under HF conditions.  相似文献   
92.
-Mannanase produced by Bacillus sp. W-2, isolated from decayed commercial konjak cake, was purified from the culture supernatant by (NH4)2 SO4 precipitation, adsorption to konjak gel, and column chromatography with DEAE-cellulose, Sephadex G-100 and Sephacryl S-200. Its molecular size was estimated by SDS-PAGE as 40 kDa, and by gel filtration as 36 kDa. The enzyme was most active at pH 7 and 70°C and was stable for at least 1 h between pH 5 and 10 and below 60°C. Its activity was completely inhibited by Hg2+. The enzyme hydrolysed galactomannan better than glucomannan and mainly produced mannose and mannobiose.The authors are with the Department of Bioproductive Science, Faculty of Agriculture, Utsunomiya University. Utsunomiya, Tochigi 321, Japan  相似文献   
93.
The structure of genetic variation in disjunct Scandinavian populations of Hippocrepis emerus was studied using allozymes and DNA fingerprinting. Variation in the three native regional populations in Scandinavia was compared with that in a recently introduced population in Sweden. In contrast to the recently introduced population, the native Scandinavian isolates of H. emerus showed high levels of allozyme fixation and low levels of DNA diversity. Variation in allozymes and at DNA fingerprint loci showed closely congruent patterns of geographic variation, with pronounced differentiation between the native Norwegian and Swedish isolates of the species. The structure of genetic variation in native Scandinavian H. emerus is interpreted in terms of historical population bottlenecks and founder events during the species' postglacial immigration into Scandinavia.  相似文献   
94.
Summary Cross-compatibility of species in section Arachis Krap. et Greg. nom. nud., and chromosome pairing and pollen fertility in their interspecific F1 hybrids were studied to further understand the phylogenetic relationships among these species. Except those with A. batizocoi Krap. et Greg. nom. nud., hybrids between diploid species have near normal bivalent frequency (9.1–9.8) and moderate to high pollen fertility (60–91%). Hybrids between A. batizocoi and other species have low bivalent frequency (5.2–6.9) and very low pollen fertility (3–7%). These results confirm the earlier separation of these species into two groups based on karyomorphology and Mahalanobis D2 calculated on arm ratios. These studies also provide a picture of relative affinities between A. batizocoi, the lone member of one cluster, and the other species, and among the rest of the species. They also indicate that the basic chromosome complement in the two groups of species is the same. Chromosome pairing in triploid hybrids, (A. hypogaea L. X diploid wild species), suggests that A. batizocoi is the closest diploid relative of A. hypogaea. It is closer to A. hypogaea subspecies fastigiata Waldron than to A. hypogaea subspecies hypogaea Krap. et. Rig. Other diploid species of the section Arachis are equidistant from A. hypogaea, and have the same genome which has strong homology to one of the genomes of A. hypogaea. Based on the present results, the two tetraploid species, A. monticola Krap. et Rig. and A. hypogaea can be recognised as two forms of the same species. Breeding implications have been discussed in the light of chromosome behaviour observed in hybrids of A. hypogaea X diploid species, and on the presumptions that A. hypogaea has an AABB genomic constitution, and that among the diploid species, the B genome is present in A. batizocoi while the A genome is common to the other diploid species of section Arachis.Submitted as Journal Article No. 328 by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)  相似文献   
95.
Summary The esterase isozymes of 432 strains of foxtail millet, Setaria italica (L.) P. Beauv., collected from different areas throughout Eurasia, were investigated by gel isoelectric focusing. Five phenotypes were recognized, based on the combination of five major activity bands. Cross experiments among different phenotypes revealed these isozymes to be controlled by two codominant alleles and a null allele on the locus, Est-1, and three codominant alleles on another independent locus, Est-2. On locus Est-1, 388 strains had Est-1 a, 41 had Est-1 b and three had Est-1 null alleles. Est-1 a was widely distributed throughout Eurasia, while the distribution of Est-1 b and Est-1 null was distinctly restricted. On locus Est-2, 417 strains had Est-2 a, nine had Est-2 b and six had Est-2 c alleles. Est-2 a was widely distributed throughout Asia to Czechoslovakia, but was not detected in the western part of Europe. Est-2 b was found in all of the strains from the western part of Europe and in one of the Indian strains. Est-2 c was rarely found in Japan and China. The distribution of Est-2 a and -2 b might indicate some degree of phylogenetic differentiation between the Asian and the European strains. Polymorphism in both loci was observed only in Chinese strains.Contribution No. 30 from the Plant Germ-plasm Institute, Faculty of Agriculture, Kyoto University, Kyoto, Japan  相似文献   
96.
Summary The aim of the present study on the fetal porcine pituitary was (1) to detect by means of the immunoperoxidase technique the earliest stages of cells producing polypeptide hormones: -MSH, ACTH, -LPH, - and -endorphin, growth hormone (GH) and prolactin (PRL), (2) to study the development of the synthesis and the storage of these hormones during fetal life, and (3) to detect whether several hormones can be located in one and the same cell.The corticotropic cells were revealed as the earliest functional elements of the fetal anterior pituitary. Our results indicate clearly that ACTH, -MSH, -LPH, - and -endorphin appear at 34 days in the same regular, round or ovoid cells; no differences in the time of their appearance could be observed. The ACTH-cells, irregular or angular in shape and endowed with cytoplasmic processes such as described in the adult pituitary, were not seen until day 50. The first GH-cells were detected between 40 to 45 days of fetal life. From day 45 to 90, the GH-cells greatly increased in number and in staining intensity of their progressively extending cytoplasmic area, but they displayed the same regular and round shape. The PRL-cells were the last cell type to appear in the fetal pituitary. The first PRL-cells, small in size and round or ovoid in shape with a high nucleus/cytoplasm ratio, were detected at day 70. At day 80, the PRL-cells increased in size and staining intensity. They displayed an irregular elongated or stellated shape and cytoplasmic processes resembling those characteristic of the adult pituitary. These data suggest that in the fetal porcine pituitary: (1) ACTH, -LPH and related peptides are synthesized and stored in the same cells, and (2) PRL and GH appear in individual cellular elements.  相似文献   
97.
The VP1 coat protein of FMDV strain A Venceslau (Aven) consists of 213 amino acid residues. Serum neutralization tests demonstrated that strain Aven is closely related to strain A Argentina/79 (A79) but significantly different from strain A24 Cruzeiro (A24). There is a strong correlation between the amino acid sequences and the serological data. Nucleotide and amino acid sequence analyses of VP1 showed that serologically related viruses (Aven and A79) differ less in this region of the genome than those of serologically distinct viruses (Aven vs. A24). The most significant variation between Aven and A24 occurs at amino acid positions 43 to 46, in which all four residues are different.  相似文献   
98.
Summary An ultrastructural analysis is presented of the cuticular and neural structures formed by the prothoracic leg and wing imaginal discs of maleDrosophila melanogaster larvae during culture in vitro with 0.2 g/ml of -ecdysone. A pupal cuticle, and subsequently an imaginal cuticle with a well-defined epicuticle and a laminated endocuticle is formed. The ultrastructure of the epidermis and of cuticular structures such as bristles, trichomes, apodemes, and tracheoles is very similar to that found in situ. Dendrites and nerve cell bodies are formed in vitro, and sensory axons form nerve bundles similar to those of normal appendages in situ, despite their isolation from the central nervous system. It is concluded that at the ultrastructural level, differentiation in vitro closely parallels the normal course of development.  相似文献   
99.
-Glucuronidase (GUS) has become an important enzyme model for the genetic study of molecular disease, enzyme realization, and therapy, and for the biogenesis and function of the lysosome and lysosomal enzymes. The genetics of human -glucuronidase was investigated utilizing 188 primary man-mouse and man-Chinese hamster somatic cell hybrids segregating human chromosomes. Cell hybrids were derived from 16 different fusion experiments involving cells from ten different and unrelated individuals and six different rodent cell lines. The genetic relationship of GUS to 28 enzyme markers representing 19 linkage groups was determined, and chromosome studies on selected cell hybrids were performed. The evidence indicates that the -glucuronidase gene is assigned to chromosome 7 in man. Comparative linkage data in man and mouse indicate that the structural gene GUS is located in a region on chromosome 7 that has remained conserved during evolution. Involvement of other chromosomes whose genes may be important in the final expression of GUS was not observed. A tetrameric structure of human -glucuronidase was demonstrated by the formation of three heteropolymers migrating between the human and mouse molecular forms in chromosome 7 positive cell hybrids. Linkage of GUS to other lysosomal enzyme genes was investigated. -Hexosaminidase HEX B) was assigned to chromosome 5; acid phosphatase2 (ACP 2) and esterase A4 (ES-A 4) were assigned to chromosome 11; HEX A was not linked to GUS; and -galactosidase (-GAL) was localized on the X chromosome. These assignments are consistent with previous reports. Evidence was not obtained for a cluster of lysosomal enzyme structural genes. In demonstrating that GUS was not assigned to chromosome 9 utilizing an X/9 translocation segregating in cell hybrids, the gene coding for human adenylate kinase1 was confirmed to be located on chromosome 9.Supported by NIH Grants HD 05196, GM 20454, and GM 06321, by NSF Grant BMS 73-07072, and by HEW Maternal and Child Health Service, Project 417.  相似文献   
100.
The effects of hyper- and hypo-saline stresses on the levels of various inorganic and organic solutes inUlva lactuca have been recorded. Hypoosmotic stress decreased the tissue concentration of K+, Na+ and Cl- while hyper-osmotic stress caused a transient increase in Na+ and a stable accumulation of K+ and Cl-. The tissue content of -dimethylsulphoniopropionate (-dimethylpropiothetin) responded to changes in salinity. The time course of hypersaline stress showed the -dimethylsulophoniopropionate concentration rose as the Na+ level fell. The levels of free sugars and amino acids, including proline, were relatively low in this alga and did not appear to be important in osmotic adjustment. The possibility that tertiary sulphonium dipolar ions have an analogous role in some algae to glycinebetaine and possibly other quaternary nitrogen compounds in higher plants as cytoplasmic osmotica is discussed briefly.Abbreviations DMSP -dimenthylsulphomiopropionate - AFT apparent free space - TLE thin layer electrophoresis - NPS ninhydrin positive substances - TLC thin layer chromatography  相似文献   
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