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41.
Crist CG Nakayashiki T Kurahashi H Nakamura Y 《Genes to cells : devoted to molecular & cellular mechanisms》2003,8(7):603-618
BACKGROUND: The [PSI+] element of the budding yeast is an aggregated form of the translation release factor Sup35 that is propagated and transmitted cytoplasmically in a manner analogous to that of mammalian prions. The N-terminal of Sup35, necessary for [PSI+], contains oligopeptide repeats and multiple Gln/Asn residues. RESULTS: We replaced the Gln/Asn-rich prion repeats of Sup35 with non-Gln/Asn repeats from heterologous yeast strains. These non-Gln/Asn repeat Sup35s propagated a novel [PSI+] variant, [PHI+], that appeared de novo 103 times more frequent than [PSI+]. [PHI+] was stably inherited in a non-Mendelian fashion, but not eliminated upon the inactivation of Hsp104, unlike known [PSI+] elements. In vitro, non-Gln/Asn repeat domains formed amyloid fibres that were shorter and grew more slowly than did Gln/Asn-rich prion domains, while [PHI+] aggregates were smaller than [PSI+] aggregates in vivo. CONCLUSIONS: These findings suggest the existence of an alternative, Hsp104-independent pathway to replicate non-Gln/Asn variant Sup35 prion seeds. 相似文献
42.
Production of Specific Antisera to Human B Lymphocytes 总被引:4,自引:0,他引:4
Peter Goodfellow Colin Barnstable Elizabeth Jones Walter F. Bodmer Michael J. Crumpton David Snary 《Tissue antigens》1976,7(2):105-117
Antisera have been prepared, in mice and rabbits, to membrane and sub-membrane fractions of human B lymphocyte derived lymphoid lines. Antisera to a protein subfraction were, after only minimal absorption, specific for human peripheral B lymphocytes, monocytes and B cell derived lymphoid lines. The antigen(s) recognised by these antisera were not the same as the previously described B-cell markers; immunoglobulin, Fc receptor, complement receptor and Ia antigens. The antigen(s) could not be removed from cells by lysostrip with anti- β2 microglobulin. 相似文献
43.
44.
Stanton WR Saleheen HN O'Riordan D Roy CR 《International journal of behavioral medicine》2003,10(4):285-298
Sun exposure in childhood is 1 of the risk factors for developing skin cancer, yet little is known about levels of exposure
at this age. This is particularly important in countries with high levels of ultraviolet radiation (UVR) such as Australia.
Among 49 children 3 to 5 years of age attending child care centers, UVR exposure was studied under 4 conditions in a repeated
measures design; sunny days, cloudy days, teacher’s instruction to stay in the shade, and a health professionals instruction
to apply sunscreen. Three different data collection methods were employed: (a) completion of questionnaire or diary by parents
and researcher, (b) polysulphone dosimeter readings, and (c) observational audits (video recording).
Results of this study indicated that more than half the children had been sunburnt (pink or red) and more than a third had
experienced painful sunburn (sore or tender) in the last summer. Most wore short sleeve shirts, short skirts or shorts and
cap, that do not provide optimal levels of skin protection. However, sunscreen was applied to all exposed parts before the
children went out to the playground. Over the period of 1 hr (9–10 a.m.) the average amount of time children spent in full
sun was 22 min. On sunny days there was more variation across children in the amount of sun exposure received. While the potential
amount of UVR exposure for young children during the hour they were outside on a sunny day was 1.45 MED (Minimum Erythemal
Dose), they received on average 0.35 MED, which is an insufficient amount to result in an erythemal response on fair skin
even without the use of sunscreen. 相似文献
45.
Thyagarajan B Lundberg R Rafferty M Campbell C 《Somatic Cell and Molecular Genetics》1998,24(5):263-272
We purified to near homogeneity a previously identified 100 kDa mammalian homologous DNA pairing protein. The purified 100 kDa protein also catalyzed high levels of cell-free homologous DNA recombination activity. This ATP-dependent activity was capable of forming conservative recombinant products between two circular, double-stranded DNA molecules. We were unable to detect any DNA polymerase, DNA ligase, or 5' or 3' exonuclease activity associated with this purified material. The purified 100 kDa protein bound silver nitrate as well as a monoclonal antibody specific for nucleolin. A recombinant protein comprised of the Escherichia coli maltos-ebinding protein fused to the carboxyl-terminal two-thirds of human nucleolin possessed homologous DNA pairing activity. These data indicate that the 100 kDa homologous DNA pairing protein is nucleolin. The observation that nucleolin can carry out homologous DNA strand pairing in vitro raises the prospect that it may function similarly in vivo. 相似文献
46.
Goldberg M Septier D Bourd K Hall R Jeanny JC Jonet L Colin S Tager F Chaussain-Miller C Garabédian M George A Goldberg H Menashi S 《Connective tissue research》2002,43(2-3):482-489
The dentino-enamel junction is not an simple inert interface between two mineralized structures. A less simplistic view suggests that the dentino-enamel junctional complex should also include the inner aprismatic enamel and the mantle dentin. At early stages of enamel formation, fibroblast growth factor (FGF)-2 is stored in and released from the inner aprismatic enamel, possibly under the control of matrix metalloproteinase (MMP)-3. The concentration peak for MMP-2 and -9 observed in the mantle dentin coincided with a very low labeling for TIMP-1 and -2, favoring the cross-talk between mineralizing epithelial and connective structures, and as a consequence the translocation of enamel proteins toward odontoblasts and pulp cells, and vice versa, the translocation of dentin proteins toward secretory ameloblasts and cells of the enamel organ. Finally, in X-linked hypophosphatemic rickets, large interglobular spaces in the circumpulpal dentin were the major defect induced by the gene alteration, whereas the mantle dentin was constantly unaffected. Altogether, these data plead for the recognition of the dentino-enamel junctional complex as a specific entity bearing its own biological characteristics. 相似文献
47.
Mailleau C Paul A Colin M Xing PX Guernier C Bernaudin JF Capeau J Brahimi-Horn MC 《Molecular genetics and metabolism》2001,72(2):122-131
Cystic fibrosis knockout mice (cftr(-/-)) die prematurely of obstruction of the intestine which may result from accumulation of dehydrated glycoconjugate-containing mucus. We noted an increase in the specific activity of [(14)C]glucosamine-labeled high-molecular weight glycoconjugates, probably mucin, in the lumen of the intestine of cftr(-/-) (homozygous) mice compared to cftr(+/+) (wild-type) and cftr(+/-) (heterozygous) mice and a decrease in the turnover of glycoconjugates of several organs of the cftr(-/-) mice. No difference in the anionic composition of secreted intestinal glycoconjugates was detected and no difference in the amount of mucin 1 (Muc1) was found in the small intestine, colon, pancreas, and lungs of the different genotypes. In addition, the spleen of the cftr(-/-) mice was significantly smaller than that of control mice and the small intestine and colon were, respectively, longer and shorter compared to control mice. These results indicate modified glycoconjugate metabolism in cystic fibrosis knockout mice and morphologic changes to the spleen and intestine where the latter modifications are possibly related to the intestinal malabsorption associated with cystic fibrosis. 相似文献
48.
Moritz S Colin M Keller M Klonjkowski B Capeau J Coutelle C Chroboczek J Brahimi-Horn MC 《Archives of virology》2003,148(1):1-18
Summary. Peptide and cationic lipid-based gene transfer vectors have shown promise for gene therapy but are still less efficient than
viral gene transfer vectors. We have examined the mechanism of gene transfer of different adenovirus-mimetic peptides in the
presence and absence of a cationic lipid, lipofectamine and/or adenovirus with the aim of improving the design of nonviral
vectors for efficient gene transfer. Three polylysine-adenovirus-mimetic peptides were synthesised and examined for their
efficacy for gene transfer. Transfection levels in four cell lines: adenovirus permissive human tracheal epithelial (56FHTE8o−), human lung carcinoma (A549), human colon carcinoma (Caco-2) cells, and adenovirus low-permissive Chinese hamster ovary
(CHO) cells, were examined. The polylysine-adenovirus-mimetic peptides increased the level of transfection of a reporter transgene
in all cell lines. Transfection was substantially increased when an adenovirus was added to cells after pre-incubation with
the vector complexes. Formulation of the peptide vector complexes with lipofectamine increased their transfection efficacy
and the subsequent addition of an adenovirus increased transfection levels even further but only in permissive cells. Pre-incubation
of cells with lipofectamine-peptide vector complexes increased cell binding of the adenovirus but uptake was only increased
in intermediate- or non-permissive cells. The addition of lipofectamine increased transgene expression of a recombinant adenovirus
in non-permissive cells but not in permissive cells. Enhancement with an adenovirus of peptide vector gene transfer is probably
due to more efficient endosome escape while enhancement of gene transfer by peptide vectors complexed to lipofectamine is
due to an increase in cellular binding and/or internalisation of the adenovirus.
Received February 8, 2002; accepted August 23, 2002 相似文献
49.
Elizabeth Farish Judith F. Barnes Hilary A. Rolton Keith Spowart Colin D. Fletcher David M. Hart 《Maturitas》1994,20(2-3):215-219
Objective: To determine the effects of tibolone, a synthetic steroid used to alleviate climacteric symptoms and prevent osteoporosis, on lipoprotein metabolism, with particular reference to lipoprotein(a) levels and HDL subfraction profiles.Design: Thirty nine postmenopausal women were treated with tibolone (Livial) 2.5 mg/day for 6 months and fasting serum lipoprotein levels were estimated at 0, 2, 4 and 6 months. Results: Lipoprotein(a) levels were reduced significantly over the 6 months from a median level of 245 (range <60–780) mg/I to 152 (range <60–530) mg/l, a reduction of 39% in the median level. A decrease was observed in approximately two thirds of the women. Reductions were noted in all 6 subjects whose pretreatment levels were high, although concentrations remained at a level associated with increased risk in all but one. There were significant decreases in triglycerides and VLDL cholesterol and no significant change in LDL cholesterol. There was a significant reduction of 18% in HDL cholesterol and a 26% reduction in the HDL2:HDL3 ratio. Conclusion: The reduction in lipoprotein(a) levels may have a beneficial effect on cardiovascular risk, which could go some way towards balancing the potentially adverse effect on the cardiovascular system caused by the reduction in HDL cholesterol. 相似文献
50.