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61.
62.
Distribution of mutations in the PEX gene in families with X-linked hypophosphataemic rickets (HYP) 总被引:8,自引:0,他引:8
Rowe PS; Oudet CL; Francis F; Sinding C; Pannetier S; Econs MJ; Strom TM; Meitinger T; Garabedian M; David A; Macher MA; Questiaux E; Popowska E; Pronicka E; Read AP; Mokrzycki A; Glorieux FH; Drezner MK; Hanauer A; Lehrach H; Goulding JN; O'Riordan JL 《Human molecular genetics》1997,6(4):539-549
Mutations in the PEX gene at Xp22.1 (phosphate-regulating gene with
homologies to endopeptidases, on the X-chromosome), are responsible for
X-linked hypophosphataemic rickets (HYP). Homology of PEX to the M13 family
of Zn2+ metallopeptidases which include neprilysin (NEP) as prototype, has
raised important questions regarding PEX function at the molecular level.
The aim of this study was to analyse 99 HYP families for PEX gene
mutations, and to correlate predicted changes in the protein structure with
Zn2+ metallopeptidase gene function. Primers flanking 22 characterised
exons were used to amplify DNA by PCR, and SSCP was then used to screen for
mutations. Deletions, insertions, nonsense mutations, stop codons and
splice mutations occurred in 83% of families screened for in all 22 exons,
and 51% of a separate set of families screened in 17 PEX gene exons.
Missense mutations in four regions of the gene were informative regarding
function, with one mutation in the Zn2+-binding site predicted to alter
substrate enzyme interaction and catalysis. Computer analysis of the
remaining mutations predicted changes in secondary structure,
N-glycosylation, protein phosphorylation and catalytic site molecular
structure. The wide range of mutations that align with regions required for
protease activity in NEP suggests that PEX also functions as a protease,
and may act by processing factor(s) involved in bone mineral metabolism.
相似文献
63.
64.
Alternative splicing of exon 14 determines nuclear or cytoplasmic localisation of fmr1 protein isoforms 总被引:6,自引:9,他引:6
Impaired expression of the FMR1 gene is responsible for the fragile X
mental retardation syndrome. The FMR1 gene encodes a cytoplasmic protein
with RNA-binding properties. Its complex alternative splicing leads to
several isoforms, whose abundance and specific functions in the cell are
not known. We have cloned in expression vectors, cDNAs corresponding to
several isoforms. Western blot comparison of the pattern of endogenous FMR1
proteins with these transfected isoforms allowed the tentative
identification of the major endogenous isoform as ISO 7 and of a minor band
as an isoform lacking exon 14 sequences (ISO 6 or ISO 12), while some other
isoforms (ISO 4, ISO 5) were not expressed at detectable levels.
Surprisingly, in immunofluorescence studies, the transfected splice
variants that exclude exon 14 sequences (and have alternate C-terminal
regions) were shown to be nuclear. Such differential localisation was
however not seen in subcellular fractionation studies. Analysis of various
deletion mutants suggests the presence of a cytoplasmic retention domain
encoded in exon 14 and of a nuclear association domain encoded within the
first eight exons that appear however to lack a typical nuclear
localisation signal.
相似文献
65.
Fifty-three children with moderately severe asthma were studied to determine the capacity of drugs to block exercise-induced bronchospasm (EIB). All 53 children demonstrated EIB (as defined by a 20% fall in FEV1 or 30% fall in FEF25-75) while receiving therapeutic theophylline (serum level 10-20 micrograms/ml). EIB was completely blocked in 47 children by an inhaled metaproterenol 10 minutes prior to exercise, in addition to the theophylline. In six children, EIB was only partially blocked when either metaproterenol or cromolyn was added to the theophylline, but was completely blocked when all three drugs were used. A small group of children may benefit from combination therapy for EIB. 相似文献
66.
The histochemical fluorescence technique for the demonstration of monoamines in the central nervous system was employed to assess the distribution of serotonin-containing neurons within the brain stem of the immature and adult stump-tailed macaque (Macaco arctoides). Microspectrofluorometric analysis was performed in order to verify the existence of serotonin within perikarya which contained yellow histofluorescence. Serotonin-containing perikarya were found within raphe nuclei including nucleus raphe-pallidus, -obscurus, -pontis, -magnus, -dorsalis, and -centralis superioralis. Serotoninergic perikarya did not appear confined exclusively to the raphe, but were observed in the reticular formation and other brain stem nuclei including the locus coeruleus and nucleus subcoeruleus. Serotoninergic cells were not seen within the brain stem at superior collicular levels.The localization of Serotoninergic perikarya in regions other than the raphe nuclei presents certain dissimilarities in relation to patterns reported in other mammalian species. 相似文献
67.
Summary The 5,969 by (base pair) DNA sequence of the apocytochrome b mitochondrial (mt) gene of race A Podospora anserina was located in a 8.5 Kbp region. This gene contained a 2,499 by subgroup IB and a 1,306 by subgroup ID intron as well as a 990 bp subgroup IB intron which is present in race A but not race s. The large subgroup IB intron and the race A specific IB intron both contained potential alternate splice sites which brought their open reading frames into phase with their upstream exon sequences. All three introns were compared with regard to their secondary structures and open reading frames to the other 30 group I introns in Podospora anserina, as well as to other fungal introns. We detected a new family of intronic ORFs comprising seven P. anserina introns, several N. crassa introns, as well as the T4td bacteriophage intron. Sequence similarities to intron-encoded endonucleases were noteworthy. The DNA sequences reported here and in the accompanying paper complete the analysis of race s and race A mitochondrial DNA. 相似文献
68.
Koukoulis G Ke Y Henley JD Cummings OW 《Archives of pathology & laboratory medicine》2001,125(10):1331-1334
CONTEXT: The pathology of small bowel obstruction in Crohn disease has not been studied extensively. Stricture formation has been attributed mainly to fibrosis, although muscularization of the submucosa has been discussed previously. OBJECTIVE: To identify additional pathologic changes in Crohn disease that could be involved in the formation of strictures. DESIGN: We reviewed 50 ileal resections from patients with Crohn disease. The histopathologic slides were reviewed initially without knowledge of the macroscopic or clinical findings. We identified an unusual muscular proliferation that we refer to as obliterative muscularization of the submucosa, defined as a thick and continuous muscle layer from the mucosal base to the muscularis propria that is at least 1 cm in length. Subsequently, histopathologic findings were correlated with macroscopic and clinical findings. RESULTS: Obliterative muscularization of the submucosa was present in 14 specimens, and in 11 of these 14 it was topographically restricted to strictures. Submucosal fibrosis was observed in sections from adjacent regions. Obliterative muscularization of the submucosa, including thick-walled vessels and hyperplastic nerves but not prominent scarring, was more common in specimens with strictures; the difference was statistically significant (P <.001). CONCLUSIONS: Obliterative muscularization of the submucosa may be pathogenetically involved in the formation of strictures either directly by causing a sustained spasm, or indirectly by minimizing the vasoprotective role of the submucosa, impairing repair and enhancing scarring. 相似文献
69.
The prevalence of hepatitis B surface antigen (HBsAg) and antibody to human immunodeficiency virus (HIV) was determined in serum or plasma specimens of 506 patients submitted to the clinical chemistry laboratory of an urban teaching hospital, and the results were correlated with "biohazard" warning labels on the specimens. Hepatitis B surface antigen, HIV antibody, or either of these were present in 32 (6.3%), 15 (3.0%), and 44 specimens (8.7%), respectively. Ten (67%) of 15 specimens with HIV antibody and nine (28%) of 32 with HBsAg bore biohazard labels. Among 473 unlabeled specimens, HIV antibody was present in five (1.1%), HBsAg was present in 23 (4.9%), and 27 (5.7%) contained either or both of these markers. All clinical and laboratory personnel should be vaccinated against hepatitis B and should handle all blood specimens as if they were infected, regardless of biohazard labeling. By fostering complacency in handling unlabeled specimens, the use of biohazard labels may paradoxically increase the risk that health care workers will be exposed to HIV and hepatitis B virus. 相似文献
70.
Jeffrey Cummings David J Kerr Stanley B Kaye 《Cancer chemotherapy and pharmacology》1987,20(3):263-264
Summary In five cancer patients we have determined the pharmacokinetics of 4-deoxydoxorubicin (4-DOX), its alcoholic metabolite 4-deoxydoxorubicinol and the occurrence of circulating 7-deoxyaglycone metabolites. The 7-deoxyaglycone of the alcohol metabolite, the major aglycone of Adriamycin (ADR) present in man, was not detected in any serum sample. The 7-deoxyaglycone of the parent drug, which appears in concentrations in excess of 30ng/ml after ADR administration, was detected in only 2/5 patients in trace amounts. These preliminary data indicate a difference in biotransformation between ADR and 4-DOX despite their close structural similarities. 相似文献