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991.
T Glaser W H Lewis G A Bruns P C Watkins C E Rogler T B Shows V E Powers H F Willard J M Goguen K O Simola 《Nature》1986,321(6073):882-887
One in 10,000 children develops Wilms' tumour, an embryonal malignancy of the kidney. Although most Wilms' tumours are sporadic, a genetic predisposition is associated with aniridia, genito-urinary malformations and mental retardation (the WAGR syndrome). Patients with this syndrome typically exhibit constitutional deletions involving band p13 of one chromosome 11 homologue. It is likely that these deletions overlap a cluster of separate but closely linked genes that control the development of the kidney, iris and urogenital tract (the WAGR complex). A discrete aniridia locus, in particular, has been defined within this chromosomal segment by a reciprocal translocation, transmitted through three generations, which interrupts 11p13. In addition, the specific loss of chromosome 11p alleles in sporadic Wilms' tumours has been demonstrated, suggesting that the WAGR complex includes a recessive oncogene, analogous to the retinoblastoma locus on chromosome 13. In WAGR patients, the inherited 11p deletion is thought to represent the first of two events required for the initiation of a Wilms' tumour, as suggested by Knudson from epidemiological data. We have now isolated the deleted chromosomes 11 from four WAGR patients in hamster-human somatic cell hybrids, and have tested genomic DNA from the hybrids with chromosome 11-specific probes. We show that 4 of 31 markers are deleted in at least one patient, but that of these markers, only the gene encoding the beta-subunit of follicle-stimulating hormone (FSHB) is deleted in all four patients. Our results demonstrate close physical linkage between FSHB and the WAGR locus, suggest a gene order for the four deleted markers and exclude other markers tested from this region. In hybrids prepared from a balanced translocation carrier with familial aniridia, the four markers segregate into proximal and distal groups. The translocation breakpoint, which identifies the position of the aniridia gene on 11p, is immediately proximal to FSHB, in the interval between FSHB and the catalase gene. 相似文献
992.
Primary structure of Torpedo californica acetylcholinesterase deduced from its cDNA sequence 总被引:11,自引:0,他引:11
M Schumacher S Camp Y Maulet M Newton K MacPhee-Quigley S S Taylor T Friedmann P Taylor 《Nature》1986,319(6052):407-409
Acetylcholinesterase, an essential enzyme of the nervous system, rapidly terminates the action of acetylcholine released into the synapse. Acetylcholinesterase is also found (in lower abundance) in extrajunctional areas of muscle and nerve and on erythrocyte membranes. Hydrodynamic analyses of the native enzyme and characterization of its dissociated subunits have revealed multiple enzyme forms which can be divided into two classes: dimensionally asymmetric forms which are usually found within the synapse and contain a collagen-like structural subunit disulphide-linked to the catalytic subunits; and globular forms which appear to be widely distributed on the outer surface of cell membranes. Both forms have been characterized in the ray Torpedo californica and, although their catalytic behaviours seem to be identical, they differ slightly in amino-acid composition, peptide maps and reactivity with certain monoclonal antibodies. Here, we report the complete amino-acid sequence of an acetylcholinesterase inferred from the sequence of a complementary DNA clone. The 575-residue protein shows significant homology with the C-terminal portion of thyroglobulin. 相似文献
993.
The polypeptide chain of the acid protease penicillo pepsin folds via an 18-stranded mixed beta-sheet into two distinct lobes separated by a 30-A long groove which is the extended substrate binding site. The catalytic residues Asp-32 and Asp-215 are located in this groove and their carboxyl groups are in intimate contact. Alignment of the amino acid sequence with that of pepsin shows regions of high homology. 相似文献
994.
A. D. Landman L. M. Sanford B. E. Howland C. Dawes E. T. Pritchard 《Cellular and molecular life sciences : CMLS》1976,32(7):940-941
Summary Testosterone has been detected in whole human saliva. Levels averaged (±SE) 295±36 and 195±25 pg/ml in adult males and females, respectively, and usually were undetectable in children. In adult males, the excretion of testosterone in saliva appeared to follow a circadian rhythm.Acknowledgments. This study was supported by grant No. MA-4454 from the Medical Research Council of Canada. The authors wish to thank Mr.D. B. Beaton for excellent technical assistance. 相似文献
995.
J. T. Chan J. O. Ford A. H. Rudolph H. S. Black 《Cellular and molecular life sciences : CMLS》1977,33(1):41-42
Summary Several physiological parameters were measured in hairless mice maintained on a diet supplemented with antioxidants. Comparisons to animals on control diet revealed higher water-soluble antioxidant content of skin and increased liver weight. Only small differences in body weight occurred and no distinct histological changes were observed in skin or liver.This investigation was supported by National Research Service Award 1 F32 CAO5062, awarded by the National Cancer Institute, and USPHS Grant CA13464-04 from the NCI. 相似文献
996.
Summary Observation by electron and phase-contrast microscopy demonstrated that inBombyx mori the dissociation of eupyrene bundles, apparently through digestion of the prostatic secretion or an endopeptidase, was promoted by the vigorously flagellating movement of apyrene spermatozoa in the spermatophore. 相似文献
997.
Requirement of either of a pair of ras-related genes of Saccharomyces cerevisiae for spore viability
Cells of the yeast, Saccharomyces cerevisiae, containing disruptions of either of two genes that are members of the ras oncogene family are viable, but haploid yeast spores carrying disruptions of both genes fail to grow. 相似文献
998.
999.
1000.
Inhibin beta in central neural pathways involved in the control of oxytocin secretion 总被引:2,自引:0,他引:2
P E Sawchenko P M Plotsky S W Pfeiffer E T Cunningham J Vaughan J Rivier W Vale 《Nature》1988,334(6183):615-617
Inhibin (I) a gonadal hormone glycoprotein which suppresses follicle-stimulating hormone (FSH) secretion from the anterior pituitary, is a heterodimer consisting of an alpha subunit and one of two distinct beta subunits. S1 nuclease analysis has revealed that RNAs encoding all three subunits (alpha, beta A and beta B) are expressed in rat brain. We report here on the localization, and a potential function, of inhibin beta in the rat brain. A cell group centred in the nucleus of the solitary tract (NTS), a major recipient of visceral sensory information, was stained immunohistochemically with antisera against synthetic fragments of I beta, but not I alpha. The distribution of I beta-stained fibres is consistent with known NTS projections, and includes a prominent projection to oxytocinergic aspects of the magnocellular neurosecretory system. 相似文献