全文获取类型
收费全文 | 1404篇 |
免费 | 165篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 28篇 |
妇产科学 | 19篇 |
基础医学 | 226篇 |
口腔科学 | 3篇 |
临床医学 | 195篇 |
内科学 | 279篇 |
皮肤病学 | 31篇 |
神经病学 | 179篇 |
特种医学 | 22篇 |
外科学 | 138篇 |
综合类 | 21篇 |
一般理论 | 1篇 |
预防医学 | 185篇 |
眼科学 | 28篇 |
药学 | 89篇 |
肿瘤学 | 99篇 |
出版年
2024年 | 4篇 |
2023年 | 23篇 |
2022年 | 35篇 |
2021年 | 68篇 |
2020年 | 41篇 |
2019年 | 74篇 |
2018年 | 59篇 |
2017年 | 49篇 |
2016年 | 53篇 |
2015年 | 62篇 |
2014年 | 52篇 |
2013年 | 83篇 |
2012年 | 116篇 |
2011年 | 120篇 |
2010年 | 52篇 |
2009年 | 49篇 |
2008年 | 69篇 |
2007年 | 66篇 |
2006年 | 52篇 |
2005年 | 51篇 |
2004年 | 49篇 |
2003年 | 44篇 |
2002年 | 38篇 |
2001年 | 26篇 |
2000年 | 19篇 |
1999年 | 20篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 16篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1979年 | 5篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1972年 | 4篇 |
1968年 | 3篇 |
排序方式: 共有1569条查询结果,搜索用时 0 毫秒
1.
Dayeel Goh M.R:C.P. Robert A. Minns F.R.C.P.E. Ph.D. Stephen D. Pye Ph.D. A. James W. Steers F.R.C.S. 《Developmental medicine and child neurology》1992,34(8):676-689
The clinical importance of intermittent intracranial pressure (ICP) elevations during sleep in hydrocephalic children is unclear. Eight studies of continuous ICP monitoring with simultaneous cerebral blood-flow velocity (CBFV) measurements were recorded during sleep in seven hydrocephalic children aged between one and 10 years. ICP was measured directly through a frontal reservoir. There were two main patterns of CBFV change in response to raised ICP: a progressive decrease in mean flow velocity and increase in resistance index, suggesting impaired haemodynamic compensation to ICP elevation due to reduced circulatory reserve in patients with limited intracranial compliance; and an increase in mean flow velocity with raised ICP, suggesting that appropriate haemodynamic compensation with increased blood-flow can occur to maintain adequate cerebral perfusion in those with sufficient circulatory reserve. Simultaneous CBFV and ICP measurements may help to identify those with reduced circulatory reserve who are at greater risk of ischaemic insult from episodic increases in ICP. 相似文献
2.
Hayley S. Mountford Dorothy V. M. Bishop Paul A. Thompson Nuala H. Simpson Dianne F. Newbury 《American journal of medical genetics. Part C, Seminars in medical genetics》2020,184(2):256-266
Sex chromosome trisomies (SCTs) (XXX, XXY, and XYY karyotypes) are associated with an elevated risk of neurodevelopmental disorders. The range of severity of the phenotype is substantial. We considered whether this variable outcome was related to the presence of copy number variants (CNVs)—stretches of duplicated or deleted DNA. A sample of 125 children with an SCT were compared with 181 children of normal karyotype who had been given the same assessments. First, we compared the groups on measures of overall CNV burden: number of CNVs, total span of CNVs, and likely functional impact (probability of loss‐of‐function intolerance, pLI, summed over CNVs). Differences between groups were small relative to within‐group variance and not statistically significant on overall test. Next, we considered whether a measure of general neurodevelopmental impairment was predicted by pLI summed score, SCT versus comparison group, or the interaction between them. There was a substantial effect of SCT/comparison status but the pLI score was not predictive of outcomes in either group. We conclude that variable presence of CNVs is not a likely explanation for the wide phenotypic variation in children with SCTs. We discuss methodological challenges of testing whether CNVs are implicated in causing neurodevelopmental problems. 相似文献
3.
Summary. The mild fowlpox vaccine, FPV M, widely used in Australia is composed of two predominant genotypes based upon differences
identifiable in restriction enzyme analyses of plaque purified derivatives of this vaccine. The differences, where identifiable,
were in the end fragments of the genomes. Five field isolates of FPV from chickens in New South Wales showed restriction enzyme
profiles closely related to the more virulent (standard) vaccine strain, FPV S. The FPV S strain differs from FPV M in both
terminal genome fragments and in the presence of a PstI fragment of approximately 10kb (this fragment was also present in
PstI digests of all of the field isolates). Plaque purified derivatives of FPV M showed similar lesion development upon inoculation
into the wing web of chickens. The field isolates showed significantly higher virulence in day-old and three-week-old chickens
in comparison with FPV M. One field isolate was similar to the FPV S vaccine. Two isolates had slowly developing wing web
lesions, caused significant secondary lesions in three-week-old chickens and generalised poxvirus infection when inoculated
into day-old chickens. For two isolates, the primary wing web lesion took even longer to develop and resolve although these
isolates did not cause generalised poxvirus infection. It was possible to identify four virulence/pathogenicity types amongst
these vaccine and field isolates of FPV. These strains may allow the characterisation of FPV encoded virulence factors. The
field strains with higher virulence may be suitable as parent strains for the construction of FPV recombinants with enhanced
immune responses to co-expressed vaccine antigens when compared with current FPV M strain based recombinants.
Received July 19, 1996 Accepted September 26, 1996 相似文献
4.
5.
Optimal insonation settings for contrast imaging are yet to be specified, mainly due to the lack of good understanding of the behaviour of the microbubbles. A satisfactory model that explains the behaviour of individual contrast agent scatterers has not yet been reported in the literature. An in vitro system based on a commercial scanner (ATL HDI3000) has been developed to investigate the backscatter of such agents. Suspensions of Definity were introduced in an anechoic tank. The frequency of transmitted ultrasound varied from 1 to 5 MHz, pulse period from 2 to 10 periods and peak negative acoustic pressure from 0.08 to 1.7 MPa. The backscatter at the fundamental and second harmonic frequency windows from the agent was normalized in terms of the corresponding components of backscatter from a blood mimicking fluid suspension. The agent provided a dominant resonance effect at 1.6 MHz transmit frequency. Second harmonic normalized backscatter averaged around 9 dB higher than the fundamental. The normalized fundamental backscatter intensity was linear with peak negative pressure. The second harmonic at resonance peaked at 0.5 MPa suggestive of bubble disruption above such pressure. The system proved capable of illustrating the ultrasonic behaviour of Definity in vitro, and the investigation suggested particular insonation conditions for optimal image enhancement using Definity. 相似文献
6.
Leah R. Ketcheson Erin E. Centeio Erin E. Snapp Hayley B. McKown Jeffrey J. Martin 《Disability and health journal》2021,14(1):100952
BackgroundChildren with intellectual and developmental disabilities (IDD) often experience increased barriers to engaging in physical activity (PA) which can stem from lack of gross motor function (GMF) development. Intervening on GMF at an early age can create better opportunities for children with IDD to engage in regular PA. In turn, increased PA can improve health outcomes and increase social skills.ObjectiveThe primary objective of this pilot study was to explore the effectiveness of a community-based GMF-focused PA intervention for improving overall motor skills and PA for children with IDD.MethodsAll study participants (n = 24) engaged in 10 weeks of programming for 1 h each week. A convenience sample was utilized.ResultsResults indicated no statistically significant changes pre to post for motor skill scores. However, a visual analysis of mean changes showed a consistent pattern of increased scores from pre to post on most skills. Additionally, we found that a change in participant locomotor skills significantly predicted change in Moderate to Vigorous Physical Activity (MVPA), F (1,11) = 5.16, Adj R2 = .26, p = .04.ConclusionsThese results suggest individualized attention on GMF may help to increase motor skills for children with IDD. This study adds to the small but growing amount of research examining the efficacy of community based adapted PA interventions. Further, study results should support continued exploration of effective approaches to address the motor delays experienced by children with IDD. 相似文献
7.
Human phase I vaccine trials of 3 recombinant asexual stage malaria antigens with Montanide ISA720 adjuvant 总被引:13,自引:0,他引:13
Allan Saul Gregor Lawrence Anne Smillie Christine M. Rzepczyk Carol Reed Darrin Taylor Karen Anderson Anthony Stowers Richard Kemp Anthony Allworth Robin F. Anders Graham V. Brown David Pye Peter Schoofs David O. Irving Shanny L. Dyer Graeme C. Woodrow William R. S. Briggs Rosemaria Reber Dieter Stürchler 《Vaccine》1999,17(23-24):3145-3159
Two phase I vaccine trials were conducted to test the immunogenicity and safety of a vaccine containing three recombinant malaria antigens from the asexual stage of Plasmodium falciparum. The three antigens are a fragment of MSP1 (190LCS.T3); MSP2 and a portion of RESA and were formulated in Montanide ISA720 adjuvant. These trials investigated the dose response of each antigen for eliciting both antibody and T-cell responses and the immunogenicity of a mixture of the antigens compared with the antigens injected separately. All three antigens elicited both antibody and T-cell responses. Strong T-cell responses were observed with 190LCS.T3 and RESA with stimulation indices exceeding 100 for peripheral blood leucocytes in some individuals. The antibody responses were generally weak. The human antibody responses observed with MSP2 in Montanide ISA720 were not significantly different from those obtained in an earlier trial which used MSP2 with alum as the adjuvant. No antigenic competition was observed: volunteers receiving a mixture of antigens had similar responses to those receiving the three antigens at separate sites. Tenderness and pain at the injection site were common over the first few days following immunization. In some volunteers, especially those receiving the highest doses tested, there was a delayed reaction at the injection site with pain and swelling occurring approximately 10 days after injection. 相似文献
8.
Jim Maas Garry Barton Vivienne Maskrey Hayley Pinto Richard Holland 《Drug and alcohol dependence》2013
Background
The cost of opiate substitution is usually considered lower in cost when methadone is used, as compared to that of buprenorphine, however the overall cost effectiveness of substitution programmes comparing the two drugs remains largely unknown.Methods
We evaluated the treatment cost and effectiveness of methadone and buprenorphine when used in an opiate substitution programme in Norfolk, UK. All programme costs, estimated from the perspective of the drug treatment clinic, were collected on 361 opiate-dependent participants over a six-month period. Total costs comprised medication (methadone or buprenorphine) costs, pharmacy supervision and dispensing costs, and drug service clinic costs. Effectiveness was measured in terms of (1) each programmes ability to retain participants in the programme for six months, and (2) the ability of the programme to accomplish complete abstinence from illicit opiate consumption.Results
Overall, mean medication-only costs of methadone were lower than that of buprenorphine, however, pharmacy and clinic costs were lower for the buprenorphine programme. The covariate-adjusted mean total cost of the two programmes was not significantly different. Mean six-month retention rates were higher on the methadone programme, therefore, the methadone programme “dominates” the buprenorphine programme as it was slightly more effective for the same cost. Conversely, when ability to stop taking illicit opiates concomitant with opiate substitution medication was considered, the buprenorphine programme was more effective with an additional cost of £903 per individual who stopped illicit opiate use.Conclusions
The provision of buprenorphine should be considered an appropriate treatment if cessation of illicit opiate use, concomitant with programme retention is considered an important outcome. 相似文献9.
10.