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11.
Sexually mature bison (Bison bison) cows were tested for both pregnancy and ovulation by means of urinary steroid metabolites and fecal steroids. The accuracy of pregnancy diagnosis was determined among 18 bison cows, in approximately the third month of gestation, by means of urinary pregnanediol-3 delta-glucuronide (PdG), urinary estrone conjugates (E1C), and fecal total estrogens (TE). Urinary PdG was 100% accurate, urinary E1C was 89% accurate, and fecal TE was 100% accurate in predicting pregnancy. Fecal progesterone (P4) and TE, as well as urinary E1C and PdG concentrations all increased from conception (August) through January, but significant differences were not apparent until November. During the rutting season ovulation was detected by increases in either urinary PdG or fecal P4 concentrations. Both pregnancy and ovulation were detected in uncaptured bison with reasonable accuracy by means of urinary and fecal steroids or their metabolites.  相似文献   
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Several mutants of Pseudomonas syringae subsp. savastanoi were tested for their ability to sense and respond to a chemotactic gradient in low concentrations of yeast extract. The mutants were deficient in one or both of the genes coding for the synthesis of the plant hormones indole-3-acetic acid (IAA) and isopentenyl adenosine. Mutations which resulted in the loss of IAA production were due to the loss of the entire plasmid containing the iaa operon or to an 18-kb deletion of the iaa region. Additional mutants tested were deficient in their ability to produce isopentenyl adenosine as a result of the loss of the ptz-bearing plasmid. In all cases, strains which had lost the ability to produce IAA exhibited enhanced motility of up to 2.5 times that of the wild type (IAA+) in medium containing 0.01% yeast extract. No differences in motility were observed on medium containing lower concentrations of yeast extract. The presence or absence of the cytokinin plasmid and the presence or absence of inorganic nitrogen in the medium had no effect on the relative mobility of the strains.  相似文献   
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Treacher Collins syndrome is an autosomal dominant condition of bilateral craniofacial abnormalities of structures derived from the first and second branchial arches. A patient with severe manifestations of Treacher Collins syndrome and a de novo chromosomal deletion in region 4p15.32----p14 was identified. Anonymous DNA sequences of loci D4S18, D4S19, D4S20, D4S22, and D4S23 were mapped to the deleted region. DNA probes previously mapped to loci on chromosome 4p (D4S10, D4S15, D4S16, D4S26, D4S35, D4S95, D4S144, RAF1P1, QDPR, and HOX7) were not deleted in this patient. Linkage analysis between the D4S18, D4S23, and QDPR loci and Treacher Collins syndrome in eight families excluded the Treacher Collins syndrome locus from the region of the deletion.  相似文献   
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A model for studying transfer of delayed-type sensitivity to mice with cellfree materials is described. The results with a particulate antigen (Candida) and 4 soluble protein antigens (PPD, ferritin, cytochrome c, and horseradish peroxidase) suggest that the phenomenon is antigen specific. Identical preparations from the spleens of insensitive donors were not active. This murine model should facilitate characterization of the immunologic and chemical properties of transfer factor.  相似文献   
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Ten feral mares free-roaming in Maryland, USA, were inoculated with porcine zonae pellucidae (PZP) protein before the breeding season for three consecutive years (1988-90). Ovarian function was monitored for 51 days during the peak of the breeding season after the third annual PZP inoculation, in seven of these mares and in four untreated control mares, by means of urinary oestrone conjugates and nonspecific progesterone metabolites. None of the ten inoculated mares became pregnant in 1990, compared with 55% of 20 control mares, which included two of the four monitored for ovarian function. Three of the untreated mares demonstrated apparent normal ovarian activity, characterized by preovulatory oestrogen peaks, concurrent progesterone nadirs at ovulation, breeding activity, and luteal-phase progesterone increases after ovulation. Two of the seven monitored PZP-treated mares demonstrated ovulatory cycles that did not result in conception. One was pregnant as a result of conception in 1989 and demonstrated a normal, late-gestation, endocrine profile. The remaining four PZP-treated mares revealed no evidence of ovulation, and urinary oestrogen concentrations were significantly depressed. The experiments indicated that (i) a third consecutive annual PZP booster inoculation is greater than 90% effective in preventing pregnancies in mares and (ii) three consecutive years of PZP treatment may interfere with normal ovarian function as shown by markedly depressed oestrogen secretion.  相似文献   
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中国的炭疽杆菌DNA分型及其地理分布   总被引:6,自引:1,他引:6  
炭疽广泛分布于中国各地,特别是西部地区,并经常造成人畜疾病,在一项合作研究中,用多位点VNTR分析(MLVA)对从1952-1998年自中国主要地理流行区域分离的病人,病畜和土壤等来源的炭疽杆菌进行了基因分型,MLVA分析结果揭示了21种新的基因型,其等位基因组合在以前世界范围分离物的研究中未曾发现,此外,分离物的分群显示,A3b组是地理上最广泛分布的基因组,说明该组可能是中国的“地方流行株”。而来自古丝绸之路重要贸易中心新疆的大量分离株其基因型特别分散。  相似文献   
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Aim To determine the factors influencing the distribution of birds in remnants in a fragmented agricultural landscape. Location Forty‐seven eucalypt remnants and six sites in continuous forest in the subhumid Midlands region of Tasmania, Australia. Methods Sites were censused over a two‐year period, and environmental data were collected for remnants. The avifauna of the sites was classified and ordinated. The abundances of bird species, and bird species composition, richness, abundance and diversity were related to environmental variables, using simple correlation and modelling. Results There were two distinct groups of sample sites, which sharply differed in species composition, richness, diversity and bird abundance, separated on the presence/absence of noisy miner (Manorina melanocephala Latham) colonies, remnant size, vegetation structural attributes and variables that reflected disturbance history. The approximate remnant size threshold for the change from one group to another was 20–30 ha. Remnant species richness and diversity were most strongly explained by remnant area and noisy miner abundance, with contributions from structural and isolation attributes in the second case. Segment richness was explained by precipitation, logging history and noisy miner abundance. Bird abundance was positively related to precipitation and negatively related to tree dieback. The 28 individual bird species models were highly individualistic, with vegetation structural variables, noisy miner abundance, climatic variables, variables related to isolation, area, variables related to floristics, disturbance variables, the nature of the matrix and remnant shape all being components in declining order of incidence. Age of the remnant did not relate to any of the dependent variables. Main conclusions Degraded and small remnants may have become more distinct in their avifaunal characteristics than might otherwise be the case, as a result of the establishment of colonies of an aggressive native bird, the noisy miner. The area, isolation and shape of remnants directly relate to the abundance of relatively few species, compared to vegetation attributes, climate and the abundance of the noisy miner. The nature of the matrix is important in the response of some species to fragmentation.  相似文献   
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