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61.
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63.
L-Lactate dehydrogenase (L-LDH, E.C. 1.1.1.27) is encoded by two or three
loci in all vertebrates examined, with the exception of lampreys, which
have a single LDH locus. Biochemical characterizations of LDH proteins have
suggested that a gene duplication early in vertebrate evolution gave rise
to Ldh-A and Ldh-B and that an additional locus, Ldh-C arose in a number of
lineages more recently. Although some phylogenetic studies of LDH protein
sequences have supported this pattern of gene duplication, others have
contradicted it. In particular, a number of studies have suggested that
Ldh-C represents the earliest divergence among vertebrate LDHs and that it
may have diverged from the other loci well before the origin of
vertebrates. Such hypotheses make explicit statements about the
relationship of vertebrate and invertebrate LDHs, but to date, no closely
related invertebrate LDH sequences have been available for comparison. We
have attempted to provide further data on the timing of gene duplications
leading to multiple vertebrate LDHs by determining the cDNA sequence of the
LDH of the tunicate Styela plicata. Phylogenetic analyses of this and other
LDH sequences provide strong support for the duplications giving rise to
multiple vertebrate LDHs having occurred after vertebrates diverged from
tunicates. The timing of these LDH duplications is consistent with data
from a number of other gene families suggesting widespread gene duplication
near the origin of vertebrates. With respect to the relationships among
vertebrate LDHs, our data are not consistent with previous claims that
Ldh-C represented the earliest divergence. However, the precise
relationships among some of the main lineages of vertebrate LDHs were not
resolved in our analyses.
相似文献
64.
There is a place for the physical anthropologist in biomedical teaching and research because of the special and unique skills possessed by this individual. However, eventual success in the health sciences environment requires the student to obtain the knowledge and background for functionally oriented teaching and research. Students interested in a biomedical teaching and research career must prepare themselves methodologically and theoretically. This requires: (1) teaching qualifications, (2) an increased emphasis on methodology and technology, (3) an increased emphasis on research and experimental design, (4) appropriate interdisciplinary courses which provide the background for both teaching and research, (5) increased interaction with graduate faculty active in research, and (6) the latitude to adapt the graduate program to meet these specific needs. Students who finish their graduate training with a marketable skill, and who can apply their unique talents to a specialized area, will have broad appeal in the job market and will considerably strengthen their career opportunities. 相似文献
65.
Adriana Goncalves Pateh Makalo Hassan Joof Sarah Burr Athumani Ramadhani Patrick Massae Aiweda Malisa Tara Mtuy Tamsyn Derrick Anna R. Last Meno Nabicassa Eunice Cassama Joanna Houghton Christine D. Palmer Harry Pickering Matthew J. Burton David C. W. Mabey Robin L. Bailey Martin R. Goodier Martin J. Holland Chrissy h. Roberts 《Human genetics》2016,135(8):939-951
NKG2C is an activating receptor that is preferentially expressed on natural killer (NK) cells. The gene encoding NKG2C (killer cell lectin-like receptor C2, KLRC2) is present at different copy numbers in the genomes of different individuals. Deletion at the NKG2C locus was investigated in a case–control study of 1522 individuals indigenous to East- and West-Africa and the association with the ocular Chlamydia trachomatis infection and its sequelae was explored. The frequency of homozygous KLRC2 deletion was 13.7 % in Gambians and 4.7 % in Tanzanians. A significantly higher frequency of the deletion allele was found in West-Africans from the Gambia and Guinea-Bissau (36.2 % p = 2.105 × 10?8, 26.8 % p = 0.050; respectively) in comparison to East-African Tanzanians where the frequency of the deletion is comparable to other human populations (20.9 %). We found no evidence for an association between the numbers of KLRC2 gene copies and the clinical manifestations of trachoma (follicular trachoma or conjunctival scarring). A new method for imputation of KLRC2 genotypes from single nucleotide polymorphism (SNP) data in 2621 individuals from the Gambia further confirmed these results. Our data suggest that NKG2C does not play a major role in trachomatous disease. We found that the deletion allele is present at different frequencies in different populations but the reason behind these differences is currently not understood. The new method offers the potential to use SNP arrays from genome wide association studies to study the frequency of KLRC2 deletion in other populations and its association with other diseases. 相似文献
66.
Peter Wimberger Jenni Burr Andy Gray Andres Lopez Paul Bentzen 《Marine biotechnology (New York, N.Y.)》1999,1(3):311-315
We describe the first microsatellites for rockfishes in the diverse genus Sebastes. Clones containing microsatellites were isolated from the genomic library of a quillback rockfish, Sebastes maliger. Twelve microsatellites are characterized; six of these are polymorphic in quillback rockfish, and eight are polymorphic in
at least one rockfish species on which they were tested. The number of alleles per variable locus ranged from 4 to 15 and
averaged 6.8. The expected heterozygosities ranged from 0.38 to 0.79 and averaged 0.60 in these loci. These loci should prove
valuable in studies examining species identification, population genetics, hybridization, paternity, kinship, and microsatellite
evolution.
Received September 8, 1998; accepted November 23, 1998. 相似文献
67.
B. Xue K. S. Ling C. L. Reid S. Krastanova M. Sekiya E. A. Momol S. Süle J. Mozsar D. Gonsalves T. J. Burr 《In vitro cellular & developmental biology. Plant》1999,35(3):226-231
Summary To facilitate the development of transgenic grapevines that are resistant to grapevine fanleaf virus (GFLV), grapevine leafroll-associated
closterovirus (GLRaV-3) and crown gall diseases, we developed a rapid system for regenerating root-stocks: Couderc 3309, Vitis riparia ‘Gloire de Montpellier’, Teleki 5C, Millardet et De Grasset 101-14, and 110 Richter via somatic embryogenesis. Embryo culture
and grape regeneration were accomplished with four media. Embryogenic calluses from anthers were induced in the initiation
medium [MS basic medium containing 20 g sucrose per L, 1.1 mg 2,4-dichlorophenoxyacetic acid (2,4-D) per L, 0.2 mg N6-benzyladenine (BA) per L, and 0.8% Noble agar). The percentage of anthers that developed into embryogenic calli ranged from
2 to 16.3% depending on the rootstock. Calluses with early globular stage embryos were cocultivated with Agrobacterium tumefaciens strain C58Z707 containing the gene constructs of interest. The genes were sense-oriented translatable and antisense coat
protein genes from GFLV and GLRaV-3, a truncated HSP90-related gene of GLRaV-3 (43K), and a virE2 del B gene from A. tumefaciens strain C58. Twenty independent transformation experiments were performed on five rootstocks. After 3–4 mo. under kanamycin
selection, secondary embryos were recovered on differentiation medium (1/2 MS salts with 10 g sucrose per L, 4.6 g glycerol
per L, and 0.8% Noble agar). Embryos that were transformed were regenerated on a medium containing MS salts with 20 g sucrose
per L, 4.6 g glycerol per L, 1 g casein hydrolysate per L, and 0.8% Noble agar. Elongated embryos were then transferred to
a rooting medium supplemented with 0.1 mg BA per L, 3 g activated charcoal per L, 1.5% sucrose, and 0.65% Bacto agar. A total
of 928 independent putative transgenic plants were propagated in the greenhouse. All plants were tested for neomycin phosphotransferase
II expression by enzyme-linked immunosorbent assay (ELISA). The presence of transgenes was assessed by polymerase chain reaction
and Southern analysis. ELISA revealed various levels of expression of GFLV coat protein in transgenic plants of Couderc 3309.
The transgenic rootstocks that have been generated are being screened to determine whether transgenes have conferred resistance
to the virus and crown gall diseases. 相似文献
68.
69.
Evaluation of Lateral-Flow Clostridium botulinum Neurotoxin Detection Kits for Food Analysis 总被引:1,自引:0,他引:1
Shashi K. Sharma Brian S. Eblen Robert L. Bull Donald H. Burr Richard C. Whiting 《Applied microbiology》2005,71(7):3935-3941
The suitability and sensitivity of two in vitro lateral-flow assays for detecting Clostridium botulinum neurotoxins (BoNTs) in an assortment of foods were evaluated. Toxin extraction and preparation methods for various liquid, solid, and high-fat-content foods were developed. The lateral-flow assays, one developed by the Naval Medical Research Center (Silver Spring, MD) and the other by Alexeter Technologies (Gaithersburg, MD), are based on the immunodetection of BoNT types A, B, and E. The assays were found to be rapid and easy to perform with minimum requirements for laboratory equipment or skills. They can readily detect 10 ng/ml of BoNT types A and B and 20 ng/ml of BoNT type E. Compared to other in vitro detection methods, these assays are less sensitive, and the assessment of a result is strictly qualitative. However, the assay was found to be simple to use and to require minimal training. The assays successfully detected BoNT types A, B, and E in a wide variety of foods, suggesting their potential usefulness as a preliminary screening system for triaging food samples with elevated BoNT levels in the event of a C. botulinum contamination event. 相似文献
70.