全文获取类型
收费全文 | 1704篇 |
免费 | 175篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 94篇 |
妇产科学 | 56篇 |
基础医学 | 273篇 |
口腔科学 | 21篇 |
临床医学 | 127篇 |
内科学 | 272篇 |
皮肤病学 | 119篇 |
神经病学 | 144篇 |
特种医学 | 92篇 |
外科学 | 134篇 |
综合类 | 135篇 |
一般理论 | 1篇 |
预防医学 | 175篇 |
眼科学 | 40篇 |
药学 | 89篇 |
中国医学 | 1篇 |
肿瘤学 | 107篇 |
出版年
2021年 | 15篇 |
2019年 | 26篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 20篇 |
2015年 | 27篇 |
2014年 | 34篇 |
2013年 | 55篇 |
2012年 | 44篇 |
2011年 | 63篇 |
2010年 | 60篇 |
2009年 | 57篇 |
2008年 | 52篇 |
2007年 | 66篇 |
2006年 | 60篇 |
2005年 | 78篇 |
2004年 | 67篇 |
2003年 | 59篇 |
2002年 | 56篇 |
2001年 | 35篇 |
2000年 | 53篇 |
1999年 | 64篇 |
1998年 | 53篇 |
1997年 | 35篇 |
1996年 | 35篇 |
1995年 | 24篇 |
1994年 | 33篇 |
1993年 | 25篇 |
1992年 | 36篇 |
1991年 | 35篇 |
1990年 | 36篇 |
1989年 | 38篇 |
1988年 | 36篇 |
1987年 | 26篇 |
1986年 | 26篇 |
1985年 | 33篇 |
1984年 | 35篇 |
1983年 | 26篇 |
1982年 | 24篇 |
1981年 | 26篇 |
1980年 | 22篇 |
1979年 | 18篇 |
1978年 | 16篇 |
1977年 | 19篇 |
1976年 | 13篇 |
1975年 | 12篇 |
1974年 | 13篇 |
1970年 | 14篇 |
1969年 | 16篇 |
1968年 | 17篇 |
排序方式: 共有1885条查询结果,搜索用时 359 毫秒
21.
A rare benign condition of uncertain etiology and pathogenesis, Synovial Chondromatosis (SC) is most often seen intraarticularly in adults but only a handful of cases have been reported extraarticularly in children. Symptoms and physical signs consist of pain, swelling, and osteoarthritic changes related to a mass effect. Here we discuss the case of a 9-year-old boy with documented SC of the knee and critically review the Epidemiology, Clinical Presentation, Gross Anatomy and Microscopic Histopathologic Features as well as the role of Imaging Studies in Diagnosis. In addition, this paper reviews Current Pathogenetic Concepts including the infrequent but distinct possibility of malignant transformation. 相似文献
22.
Mahadevaiah SK; Odorisio T; Elliott DJ; Rattigan A; Szot M; Laval SH; Washburn LL; McCarrey JR; Cattanach BM; Lovell-Badge R; Burgoyne PS 《Human molecular genetics》1998,7(4):715-727
An RNA-binding motif (RBM) gene family has been identified on the human Y
chromosome that maps to the same deletion interval as the 'azoospermia
factor' (AZF). We have identified the homologous gene family (Rbm) on the
mouse Y with a view to investigating the proposal that this gene family
plays a role in spermatogenesis. At least 25 and probably >50 copies of
Rbm are present on the mouse Y chromosome short arm located between Sry and
the centromere. As in the human, a role in spermatogenesis is indicated by
a germ cell-specific pattern of expression in the testis, but there are
distinct differences in the pattern of expression between the two species.
Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are
female due to a position effect resulting in non-expression of Sry ;
sex-reversing such mice with an Sry transgene produces males with a high
incidence of abnormal sperm, making this the third deletion interval on the
mouse Y that affects some aspect of spermatogenesis. Most of the copies of
Rbm map to this deletion interval, and the Yd1males have markedly reduced
Rbm expression, suggesting that RBM deficiency may be responsible for, or
contribute to, the abnormal sperm development. In man, deletion of the
functional copies of RBM is associated with meiotic arrest rather than
sperm anomalies; however, the different effects of deletion are consistent
with the differences in expression between the two species.
相似文献
23.
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
24.
Evaluation of the single radial haemolysis (SRH) technique for rubella antibody measurement.
下载免费PDF全文
![点击此处可从《Journal of clinical pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S M Russell S R Benjamin M Briggs M Jenkins P P Mortimer S B Payne 《Journal of clinical pathology》1978,31(6):521-526
Sera from 1258 individuals have been tested by four laboratories for rubella antibody by both the haemagglutination-inhibition and single radial haemolysis techniques. There was good agreement between the results obtained by the two methods. Although sheep red blood cells were used in the single radial haemolysis plates, no problems were encountered with sera from patients with infectious mononucleosis. The single haemolysis technique was found to be simple, convenient, and reliable, and suited to the rapid screening of large numbers of sera to assess susceptibility to rubella in the context of a vaccination campaign. However, since the technique does not detect anti-rubella IgM, it should not be used as the only test to investigate suspected recent infection. 相似文献
25.
Language fMRI abnormalities associated with FOXP2 gene mutation 总被引:8,自引:0,他引:8
Liégeois F Baldeweg T Connelly A Gadian DG Mishkin M Vargha-Khadem F 《Nature neuroscience》2003,6(11):1230-1237
Half the members of the KE family suffer from a speech and language disorder caused by a mutation in the FOXP2 gene. We examined functional brain abnormalities associated with this mutation using two fMRI language experiments, one involving covert (silent) verb generation and the other overt (spoken) verb generation and word repetition. The unaffected family members showed a typical left-dominant distribution of activation involving Broca's area in the generation tasks and a more bilateral distribution in the repetition task, whereas the affected members showed a more posterior and more extensively bilateral pattern of activation in all tasks. Consistent with previously reported bilateral morphological abnormalities, the affected members showed significant underactivation relative to the unaffected members in Broca's area and its right homolog, as well as in other cortical language-related regions and in the putamen. Our findings suggest that the FOXP2 gene is critically involved in the development of the neural systems that mediate speech and language. 相似文献
26.
The paper reports a study of standardization and quality controlof sperm concentration counts and visual motility assessmentsin human semen analyses performed for infertility investigationsand from internal quality control procedures. Sperm concentrationdeterminations were performed in Improved Neubauer haemocytometerson volumetric dilutions made using a positive displacement pipettorfor sampling the liquefied semen. In addition to a standard1+19 dilution a second dilution of either 1+9, 1+19 or 1+49was made according to whether the estimated sperm concentrationwas <20, 20100 or > 100 x l06/ml respectively.The duplicate determinations of sperm concentration were highlysignificantly correlated (P << 0.001) with <5% variability.Parallel visual sperm motility assessments were made by twopairs of technicians and showed highly significant correlations(P << 0.001) between technicians in the determinationof the percentages of motile and progressive spermatozoa aswell as the subjective rating of sperm progressivity. When thesevalues were incorporated into a calculated motility index whichgave added weight to the progressive spermatozoa and to theirquality of progression the correlations between techniciansremained highly significant (P << 0.001) with averagedifferences of the order of 1.0%. Therefore, provided that sufficientattention is paid to technician training, regular standardizationchecks and the use of only proven reliable procedures, quantitativelyaccurate values for sperm concentration and motility can beobtained in routine semen analyses. 相似文献
27.
Summary Genetic analyses of n-alkane non-utilizing mutants of the yeast Yarrowia (Saccharomycopsis) lipolytica were continued. By analyses of inter-mutant complementation and recombination a total of 26 genetic loci have been identified. Mutations representing these loci have phenotypes characteristic of defects in substrate uptake or in one or more of the enzymatic activities making up the hydroxylase complex. Tests of 14C n-hexadecane uptake by a set of alkane-negative mutants representing the 26 loci show that 16 of the mutations cause a significant reduction in n-alkane uptake. N-alkane uptake by Y. lipolytica is shown to be inducible and to be inhibited by the metabolic poisons 2–4 dinitrophenol and KCN. The latter observation indicates that n-alkane uptake of Y. lipolytica is due to active transport. 相似文献
28.
29.