全文获取类型
收费全文 | 2002篇 |
免费 | 145篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 104篇 |
妇产科学 | 38篇 |
基础医学 | 260篇 |
口腔科学 | 74篇 |
临床医学 | 166篇 |
内科学 | 370篇 |
皮肤病学 | 40篇 |
神经病学 | 175篇 |
特种医学 | 114篇 |
外科学 | 282篇 |
综合类 | 42篇 |
预防医学 | 163篇 |
眼科学 | 62篇 |
药学 | 110篇 |
中国医学 | 1篇 |
肿瘤学 | 133篇 |
出版年
2021年 | 17篇 |
2019年 | 35篇 |
2018年 | 27篇 |
2017年 | 16篇 |
2016年 | 23篇 |
2015年 | 23篇 |
2014年 | 44篇 |
2013年 | 81篇 |
2012年 | 87篇 |
2011年 | 56篇 |
2010年 | 58篇 |
2009年 | 43篇 |
2008年 | 68篇 |
2007年 | 69篇 |
2006年 | 71篇 |
2005年 | 76篇 |
2004年 | 62篇 |
2003年 | 66篇 |
2002年 | 58篇 |
2001年 | 38篇 |
2000年 | 51篇 |
1999年 | 41篇 |
1998年 | 34篇 |
1997年 | 53篇 |
1996年 | 47篇 |
1995年 | 31篇 |
1994年 | 38篇 |
1993年 | 27篇 |
1992年 | 46篇 |
1991年 | 47篇 |
1990年 | 44篇 |
1989年 | 52篇 |
1988年 | 39篇 |
1987年 | 47篇 |
1986年 | 42篇 |
1985年 | 54篇 |
1984年 | 29篇 |
1982年 | 24篇 |
1981年 | 17篇 |
1980年 | 21篇 |
1979年 | 40篇 |
1978年 | 27篇 |
1977年 | 21篇 |
1976年 | 22篇 |
1975年 | 18篇 |
1974年 | 20篇 |
1973年 | 21篇 |
1972年 | 28篇 |
1971年 | 25篇 |
1970年 | 17篇 |
排序方式: 共有2149条查询结果,搜索用时 265 毫秒
21.
D Shore C R Filson W E Johnson D S Rae P Muehrer D J Kelley T S Davis I N Waldman R J Wyatt 《The American journal of psychiatry》1989,146(5):645-651
The authors studied arrest records and clinical data on 217 persons formerly hospitalized as "White House Cases" because they were psychotically preoccupied with prominent political figures. Prior arrest for violent crime was the variable most strongly associated with arrest for violent crime after hospital discharge. Male gender and a history of weapons possession were also correlated with future violence. For those with prior violent crime arrests, hospital incidents requiring seclusion were also associated with later violence. For those without prior arrests, subsequent violence was associated with threats, living outside Washington, and command hallucinations. For those previously arrested for nonviolent crimes, only persecutory delusions were associated with later violence. 相似文献
22.
23.
Enhanced interleukin 1 generation by monocytes in vitro is temporally linked to an early event in the onset or exacerbation of rheumatoid arthritis. 总被引:9,自引:5,他引:9
下载免费PDF全文
![点击此处可从《Clinical and experimental immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Twenty-one patients with rheumatoid arthritis (RA) and 12 age and sex matched healthy controls were examined for the ability of their monocytes (adherent cells, AC) to spontaneously secrete interleukin 1 (IL-1) and for their peripheral blood mononuclear cells (PBMC) to secrete interleukin 2 (IL-2) induced by Staphylococcal Protein A (SPA). All RA patients had PBMC which secreted normal amounts of mitogen induced IL-2 regardless of disease activity or disease history. However, AC from RA patients who had a recent (less than 6 months) onset of their disease, or exacerbation of existing RA, had enhanced spontaneous IL-1 secretion. AC from patients with equally active RA but with historically stable disease generated normal amounts of IL-1. Enhanced in vitro IL-1 generation by circulating monocytes is temporally linked to an early event in the onset of exacerbation of RA. 相似文献
24.
25.
S. Shousha A. Schoenfeld Jill Moss I. Shore H. D. Sinnett 《Ultrastructural pathology》1994,18(5):519-523
Although recent epidemiologic studies suggest that silicone augmentation of the breast is not associated with an increased risk of mammary carcinoma, cases of breast carcinoma arising in augmented breasts are being increasingly encountered as a large number of patients who had augmentation are getting older. A case of a 51-year-old woman with a 20-year history of breast augmentation who developed an invasive cribriform carcinoma associated with extensive microcalcification is presented. The patient had submammary silicone implants 20 years ago that were replaced, because of local complications, in subpectoral positions 10 years later. Dispersive X-ray microanalysis failed to demonstrate silicone in sections of the tumor and adjacent breast tissue. Appropriately fixed tumor tissue was available for electron microscopic examination. The tumor cells were rich in mitochondria, and their luminal surfaces were endowed with abundant microvilli, but the cell surfaces that came closest to the calcified microspheriols were devoid of microvilli and had cellular buddings between the microspheriols. It is suggested that the tumor cells might have been actively involved in the process of microcalcification. 相似文献
26.
Lysis of herpes simplex virus-infected cells early in the infectious cycle by human antiviral antibody and complement. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Chang liver (CL) cells and human embryonic lung fibroblasts (MRC-5) were infected with type 1 herpes simplex virus (HSV), ant the time postinfection at which these cells became susceptible to lysis by antiviral antibody and complement of human origin was determined in a 51Cr release assay. Using a 1:2 dilution of fresh HSV antibody-positive human serum, we initially detected specific lysis by 4 h postinfection in HSV-infected CL cells and by 3 h postinfection in HSV-infected MRC-5 cells in suspension. MRC-5 cells were more completely lysed than CL cells. Protein inhibition studies with cycloheximide showed that all of the HSV-infected CL cells and most (83%) of the HSV-infected MRC-5 cells injured early in the infectious cycle were attacked because of newly synthesized viral surface antigens rather than because of adherent input virus. Suspension cells early in the infectious cycle were less completely lysed and required higher concentrations of both antiviral antibody and complement for lysis than cells that were in the later stages of infection (18 h postinfection). Guinea pig serum was inferior to human serum as a complement source for lysis of early infectious cycle cells. Lysis early in the infectious cycle was directly proportional to the multiplicity of infection and inversely proportional to the cell concentration. Infected cells in monolayers were lysed less readily and about 1 to 2 h later in the infectious cycle than infected cells in suspension. This difference was pronounced for CL cells, but modest for MRC-5 cells. These studies demonstrate that, despite previously held notions, HSV-infected tissue culture cells can be lysed by antiviral antibody and complement early in the infectious cycle before the initial production of progeny virus particles. The demonstration of lysis was highly dependent on experimental conditions, however, including cell type, suspension versus monolayer culture, cell density, and concentration of antibody and complement as well as the source of complement. 相似文献
27.
Linkage exclusion and mutational analysis of the noggin gene in patients with fibrodysplasia ossificans progressiva (FOP) 总被引:1,自引:0,他引:1
Xu MQ Feldman G Le Merrer M Shugart YY Glaser DL Urtizberea JA Fardeau M Connor JM Triffitt J Smith R Shore EM Kaplan FS 《Clinical genetics》2000,58(4):291-298
Fibrodysplasia ossificans progressiva (FOP) is an extremely rare and disabling genetic disorder characterized by congenital malformation of the great toes and by progressive heterotopic endochondral ossification in predictable anatomical patterns. Although elevated levels of bone morphogenetic protein 4 (BMP4) occur in lymphoblastoid cells and in lesional cells of patients with FOP, mutations have not been identified in the BMP4 gene, suggesting that the mutation in FOP may reside in a BMP4-interacting factor or in another component of the BMP4 pathway. A powerful antagonist of BMP4 is the secreted polypeptide noggin. A recent case report described a heterozygous 42-bp deletion in the protein-coding region of the noggin gene in a patient with FOP. In order to determine if noggin mutations are a widespread finding in FOP, we examined 31 families with 1 or more FOP patients. Linkage analysis with an array of highly polymorphic microsatellite markers closely linked to the noggin gene was performed in four classically-affected multigenerational FOP families and excluded linkage of the noggin locus to FOP (the multipoint lod score was -2 or less throughout the entire range of markers). We sequenced the noggin gene in affected members of all four families, as well as in 18 patients with sporadic FOP, and failed to detect any mutations. Single-strand conformation polymorphism (SSCP) analysis of 4 of these patients plus an additional 9 patients also failed to reveal any mutations. Among the samples analyzed by SSCP and DNA sequencing was an independently obtained DNA sample from the identical FOP patient previously described with the 42-bp noggin deletion; no mutation was detected. Examination of the DNA sequences of 20 cloned noggin PCR products, undertaken to evaluate the possibility of a somatic mutation in the noggin gene which could be carried by a small subset of white blood cells, also failed to detect the presence of the reported 42-bp deletion. We conclude that mutations in the coding region of noggin are not associated with FOP. 相似文献
28.
Synergy between the genes for butyrylcholinesterase K variant and apolipoprotein E4 in late-onset confirmed Alzheimer's disease 总被引:5,自引:2,他引:5
The allelic frequency of the gene for the K variant of
butyrylcholinesterase (BCHE-K) was 0.17 in 74 subjects with late-onset (age
> 65 years) histopathologically diagnosed Alzheimer's disease (AD),
which was higher than the frequencies in 104 elderly control subjects
(0.09), in 14 early-onset cases of confirmed AD (0.07) and in 29 confirmed
cases of other dementia (0.10). The association of BCHE-K with late-onset
AD was limited to carriers of the epsilon 4 allele of the apolipoprotein E
gene (APOE), among whom the presence of BCHE-K gave an odds ratio of
confirmed late-onset AD of 6.9 (95% C.I. 1.65-29) in subjects > 65 years
and of 12.8 (1.9-86) in subjects > 75 years. In APOE epsilon 4 carriers
over 75 years, only 1/22 controls, compared with 10/24 confirmed late-onset
AD cases, had BCHE-K. We suggest that BCHE-K, or a nearby gene on
chromosome 3, acts in synergy with APOE epsilon 4 as a susceptibility gene
for late-onset AD.
相似文献
29.
Faust RA Shore EM Stevens CE Xu M Shah S Phillips CD Kaplan FS 《American journal of medical genetics. Part A》2003,(1):71-75
We describe a rare case of progressive osseous heteroplasia of the face in a child. Biopsy showed osteoma cutis superficially with ectopic bone formation in the deeper tissues including skeletal muscle. Analysis of DNA from peripheral blood leukocytes showed mutations in the gene encoding the alpha subunit of the stimulatory G protein of adenylyl cyclase (GNAS1), confirming the diagnosis of progressive osseous heteroplasia. 相似文献
30.
Monte Carlo calculations have been made to determine the energies delivered by photons and neutrons to the human body irradiated by collimated photon beams. The beams were monoenergetic and ranged from 100 keV to 40 MeV. The energy deposition in the body was sorted into two regions: inside and outside the irradiated volume. Most of the results obtained were for a beam size of 100 cm2 although some calculations were also made to 600 cm2 beams. The effect of beam size on energy deposition in the two regions was investigated for 60Co gamma rays. Graphs are presented which give the integral doses delivered by neutrons and photons to the two regions for therapy beams of various energies. These graphs can be used to calculate the integral doses which are delivered inside and outside the treatment volume for photon spectra from most medical accelerators. Calculations of energy deposition were also made for the spectra from two particular accelerators. These were done using Monte Carlo as well as by simply "folding" the spectra into the results for monoenergetic photons. The results obtained by both methods were in good agreement and indicated that the integral doses deposited outside the treatment volume by neutrons are more than two orders of magnitude smaller than those deposited by scattered photons. 相似文献