全文获取类型
收费全文 | 879篇 |
免费 | 52篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 18篇 |
妇产科学 | 8篇 |
基础医学 | 162篇 |
口腔科学 | 13篇 |
临床医学 | 125篇 |
内科学 | 221篇 |
皮肤病学 | 7篇 |
神经病学 | 68篇 |
特种医学 | 97篇 |
外科学 | 80篇 |
综合类 | 7篇 |
预防医学 | 37篇 |
眼科学 | 6篇 |
药学 | 59篇 |
中国医学 | 1篇 |
肿瘤学 | 35篇 |
出版年
2023年 | 7篇 |
2021年 | 16篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 12篇 |
2016年 | 13篇 |
2015年 | 16篇 |
2014年 | 22篇 |
2013年 | 26篇 |
2012年 | 26篇 |
2011年 | 35篇 |
2010年 | 22篇 |
2009年 | 21篇 |
2008年 | 33篇 |
2007年 | 53篇 |
2006年 | 34篇 |
2005年 | 38篇 |
2004年 | 31篇 |
2003年 | 37篇 |
2002年 | 27篇 |
2001年 | 17篇 |
2000年 | 21篇 |
1999年 | 19篇 |
1998年 | 18篇 |
1997年 | 14篇 |
1996年 | 18篇 |
1995年 | 14篇 |
1994年 | 18篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 17篇 |
1989年 | 16篇 |
1988年 | 21篇 |
1987年 | 30篇 |
1986年 | 27篇 |
1985年 | 23篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1975年 | 12篇 |
1974年 | 7篇 |
1973年 | 5篇 |
1972年 | 12篇 |
1971年 | 5篇 |
1970年 | 5篇 |
排序方式: 共有953条查询结果,搜索用时 15 毫秒
1.
Staphylococcus aureus osteomyelitis and pyogenic arthritis has a different pattern in the elderly than in the young. The axial skeleton is the most frequent site of infection and treatment is usually by intravenous antibiotics. We report a case ofStaph. aureus septic arthritis of the elbow with concomitant osteomyelitis of the spine that was thought to be due toStaph. aureus, but culture of debrided material from the lesion grewBrucella in culture. We suggest that in the elderly it is advisable to obtain a tissue culture diagnosis and not to instigate therapy based on positive blood cultures or a concomitant infection. 相似文献
2.
An innocuous sensory event (a prestimulus) that briefly precedes a startle-eliciting stimulus (SES) will reduce the amplitude
of the subsequently elicited reflex. In three experiments brief silent periods in otherwise continuous noise (gaps) were used
as prestimuli to investigate the effects of the D1 dopamine receptor agonist (±)-SKF-38393 (SKF) and the dopamine D2 receptor group agonist (−)-quinpirole hydrochloride on gap inhibition of the rat’s acoustic startle reflex. Gap durations
of 4 and 50 ms were analyzed. Quinpirole (0–1.6 mg/kg) had a biphasic effect on gap inhibition. Lower doses increased gap
inhibition, an effect that peaked at the 0.4 mg/kg dose. For higher doses, inhibition returned to control levels for the 4-ms
long gap, but remained elevated for the 50-ms long gap. SKF had no effect on gap inhibition, and haloperidol (0.2 mg/kg) reversed
the quinpirole-induced increase of gap inhibition. These data implicate the D2 dopamine receptor group in gap inhibition of startle modulation. The results are discussed in terms of the effects of catecholamine
agonists on attention.
Received: 25 July 1995/Final version: 28 April 1997 相似文献
3.
WW Thompson 《Transfusion》1993,33(4):333-335
This study was designed to determine the blood donation behavior and attitudes of Hispanic residents of the Lower Rio Grande Valley for the purpose of developing promotional and educational approaches to enhance levels of donor participation. Personal interviews of 545 respondents were conducted in English and Spanish using quota sampling and standard intercept techniques at lower- and middle-income supermarkets in five cities during a payday weekend. A number of research hypotheses were established to test for demographic, behavioral, and attitudinal differences that were observed in donors and nondonors using chi-square analysis and multiple discriminant analysis. After analyzing the difference between Hispanics and non-Hispanics for blood donation rates, all non-Hispanics were eliminated from analysis, and the remaining 419 Hispanics were evaluated on the basis of their donor behavior. Donation among Hispanics was most likely to be by better- educated, English-speaking, higher-job-status individuals who had participated in a blood donation drive. Donors tend to have parent(s) who were donors, and they were also more likely to carry an organ donor card. Donors were found to vary in their behaviors as well as their attitudes and beliefs. Perceptions of a lack of safety in donating, the risk of contracting acquired immune deficiency syndrome, and the financial motivation of donors were most pronounced among Hispanics, which indicated a need for improved education on these issues. 相似文献
4.
Experimental vaccination of young chickens with a live, non-pathogenic strain of Escherichia coli 总被引:1,自引:0,他引:1
A non-pathogenic, piliated strain of Escherichia coli (BT-7; Frommer et al., 1990), isolated from a meat-type chicken flock, was studied as a candidate for a live vaccine to protect chickens from E. coli infection. Active immunization provided substantial protection of chicks vaccinated at 14 or 21 days of age, resulting in better resistance to challenge than in those vaccinated at 1 or 7 days. Chicks vaccinated at 21 days of age and challenged 1 week later with pathogenic E. coli strains 01-.K1, 02:K1 or 078:K80, exhibited good protection for at least 2 weeks against all strains. Three vaccination routes were found to give the highest resistance to challenge with pathogenic E. coli strain 078:K80. Intramuscular (i.m.) at 7 and 21 days of age, i.m. at 21 days of age and spray at 7, followed by per os at 21 days of age. Vaccination per os once at 7 or twice at 7 and 21 days resulted in good protection. Chicks exhibiting high antibody titres by ELISA were well-protected against challenge. 相似文献
5.
C3d binding to the circumsporozoite protein carboxy-terminus deviates immunity against malaria 总被引:5,自引:0,他引:5
Bergmann-Leitner ES Scheiblhofer S Weiss R Duncan EH Leitner WW Chen D Angov E Khan F Williams JL Winter DB Thalhamer J Lyon JA Tsokos GC 《International immunology》2005,17(3):245-255
The immunogenicity of recombinant protein or anti-viral DNA vaccines can be significantly improved by the addition of tandem copies of the complement fragment C3d. We sought to determine if the efficacy of a circumsporozoite protein (CSP)-based DNA vaccine delivered to mouse skin by gene gun was improved by using this strategy. Instead, we found that C3d suppressed the protective immunity against Plasmodium berghei malaria infection and deviated immunity, most notably by suppressing the induction of antibodies specific for the CSP C-terminal flanking sequence and by suppressing the induction of CSP-specific IL-4-producing spleen cells. We further showed that C3d bound to the C-terminal flanking sequence of the CSP, which may explain the immune deviation observed in CS/C3d chimeric antigen. We have thus identified C3d-mediated epitope masking and shifting of both the humoral and cellular immune responses as a potential novel escape mechanism, which plasmodia may use to divert the induction of protective immunity. 相似文献
6.
Human leukocyte antigen matching and fetal loss: results of a 10 year prospective study 总被引:6,自引:0,他引:6
Ober C; Hyslop T; Elias S; Weitkamp LR; Hauck WW 《Human reproduction (Oxford, England)》1998,13(1):33-38
The role that maternal and fetal human leukocyte antigen (HLA) genes play
in pregnancy is unknown, but it has been suggested that fetuses whose HLA
alleles do not differ from maternal alleles (i.e. histocompatible fetuses)
are more likely to be aborted than fetuses with HLA alleles that differ
from maternal alleles (i.e. histoincompatible fetuses). To elucidate the
role of HLA compatibility in pregnancy, we tested the hypothesis that
couples who match for HLA alleles or haplotypes would have reduced
fertility because only these couples could produce histocompatible fetuses.
We conducted a 10 year prospective study of HLA matching and pregnancy
outcome in 111 Hutterite couples, providing information on 251 pregnancies.
A logistic regression analysis was performed to determine the effects of
HLA matching at HLA regions and loci on pregnancy outcome (fetal loss
versus delivery). Significantly increased fetal loss rates were observed
among couples matching for the entire 16-locus haplotype (P = 0.002). Among
the individual loci, loss rates were increased among couples matching for
HLA-B (P = 0.019), HLA-C (P = 0.033) and the complement component, C4 (P =
0.043). We interpret these results as evidence that matching for the entire
16-locus haplotype and/or alleles at an HLA-B-linked locus confers
significant risk for fetal loss.
相似文献
7.
Scheiblhofer S Chen D Weiss R Khan F Mostböck S Fegeding K Leitner WW Thalhamer J Lyon JA 《European journal of immunology》2001,31(3):692-698
The C terminus of the circumsporozoite protein (CSP) is anchored to the parasite cell membrane by a glycosylphosphatidylinositol (GPI) glycolipid. This GPI signal sequence functions poorly in heterologous eukaryotic cells, causing CSP retention within internal cell organelles during genetic immunization. Cellular location of antigen has quantitative and qualitative effects on immune responses induced by genetic immunization. Removal of the GPI signal sequence had a profound effect on induction and efficacy of CSP-specific immune response after genetic immunization of BALB/c mice with a gene gun. The CSP produced from the plasmid lacking the GPI anchor signal sequence (CSP-A) was secreted and soluble, but that produced by the CSP+A plasmid was not. The CSP-A plasmid induced a highly polarized Th2 type response, in which the CSP-specific IgG antibody titer was three- to fourfold higher, and the protective effect was significantly greater than that induced by the CSP+A plasmid. Thus, these two physical forms of CSP induced quantitatively and qualitatively different immune responses that also differed in protective efficacy. Engineering plasmid constructs for proper cellular localization of gene products is a primary consideration for the preparation of optimally efficacious DNA vaccines. 相似文献
8.
9.
Detection of methicillin-resistant Staphylococcus aureus and simultaneous confirmation by automated nucleic acid extraction and real-time PCR
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Grisold AJ Leitner E Mühlbauer G Marth E Kessler HH 《Journal of clinical microbiology》2002,40(7):2392-2397
A molecular assay for the simultaneous detection of a Staphylococcus aureus-specific gene and the mecA gene, responsible for the resistance to methicillin in staphylococci, was evaluated. The assay included an automated DNA extraction protocol conducted with a MagNA Pure instrument and real-time PCR conducted with a LightCycler instrument. The performance and robustness of the assay were evaluated for a suspension of methicillin-resistant S. aureus (MRSA) strain with a turbidity equivalent to a McFarland standard of 0.5, which was found to be the ideal working concentration. The specificity of the new molecular assay was tested with a panel of 30 gram-negative and gram-positive bacterial strains other than MRSA. No cross-reactivity was observed. In a clinical study, 109 isolates of MRSA were investigated. All clinical MRSA isolates gave positive results for the S. aureus-specific genomic target, and all but one were positive for the mecA gene. In conclusion, the new molecular assay was found to be quick, robust, and laborsaving, and it proved to be suitable for a routine molecular diagnostic laboratory. 相似文献
10.
Methods for non-invasive detection of ventricular late potentials--a comparative multicenter study 总被引:2,自引:0,他引:2
M Oeff E R von Leitner R Sthapit G Breithardt M Borggrefe U Karbenn T Meinertz R Zotz W Clas V Hombach 《European heart journal》1986,7(1):25-33
To evaluate the methodological problems of the non-invasive registration of late potentials the results obtained with four different averaging devices in the same 109 patients were compared. The high-resolution ECG was obtained from the body surface, high-gain amplified and filtered. With the averaging technique, the improved signal-to-noise ratio was able to detect low-amplitude cardiac activity. The incidence of late potentials detected with the four averaging systems, whose characteristics are described, ranged between 12% and 21%. Corresponding positive results were obtained in 5.5%, corresponding negative results in 68.8%. The reasons for differing results were mainly due to differences in visual or automatic interpretation of the registered fractionated electrical cardiac activity. Additionally, the determination of the end of QRS using the QRS width, obtained from reference leads, may influence the specificity of the methods. 相似文献