全文获取类型
收费全文 | 236篇 |
免费 | 15篇 |
专业分类
儿科学 | 12篇 |
妇产科学 | 32篇 |
基础医学 | 33篇 |
口腔科学 | 14篇 |
临床医学 | 59篇 |
内科学 | 19篇 |
皮肤病学 | 1篇 |
神经病学 | 8篇 |
特种医学 | 18篇 |
外科学 | 13篇 |
综合类 | 4篇 |
预防医学 | 18篇 |
药学 | 13篇 |
中国医学 | 3篇 |
肿瘤学 | 4篇 |
出版年
2021年 | 5篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 12篇 |
2017年 | 7篇 |
2015年 | 17篇 |
2014年 | 11篇 |
2013年 | 12篇 |
2012年 | 15篇 |
2011年 | 20篇 |
2010年 | 13篇 |
2009年 | 12篇 |
2008年 | 8篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1977年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有251条查询结果,搜索用时 15 毫秒
1.
M. Esposito P. Coulthard R. Oliver P. Thomsen HV Worthington 《Australian dental journal》2004,49(4):205-205
A substantive amendment to this systematic review was last made on 15 March 2003. Cochrane reviews are regularly checked and updated if necessary. Background Some dental implant failures may be due to bacterial contamination at implant insertion. Infections around biomaterials are difficult to treat and almost all infected implants have to be removed. In general, antibiotic prophylaxis in surgery is only indicated for patients at risk of infectious endocarditis, for patients with reduced host‐response, when surgery is performed in infected sites, in cases of extensive and prolonged surgical interventions and when large foreign materials are implanted. To minimize infections after dental implant placement various prophylactic systemic antibiotic regimens have been suggested. More recent protocols recommended short term prophylaxis, if antibiotics have to be used. With the administration of antibiotics adverse events may occur, ranging from diarrhoea to life‐threatening allergic reactions. Another major concern associated with the widespread use of antibiotics is the selection of antibiotic‐resistant bacteria. The use of antibiotics in implant dentistry is controversial. It would be useful to know whether prophylactic antibiotics are effective in reducing failures of dental implants. Objectives T o assess the beneficial or harmful effects of the administration of prophylactic antibiotics for dental implant placement versus no antibiotic/placebo administration and if antibiotics are of benefit, to find which type, dosage and duration is the most effective. Search strategy We searched the Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. We handsearched several dental journals. No language restrictions were applied. Personal contacts and manufacturers of dental implants were contacted to identify unpublished trials. Most recent search: March 2003. Selection criteria Randomized controlled clinical trials (RCTs) with a follow‐up of at least three months comparing the administration of various prophylactic antibiotics regimens and no antibiotics/placebo to patients undergoing dental implant placement. Outcome measures were prosthesis failures, implant failures, postoperative infections and adverse events (gastrointestinal, hypersensitivity). Data collection and analysis Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were to be conducted in duplicate and independently by two reviewers. Results were to be expressed as random effects models using weighted mean differences for continuous outcomes and relative risk for dichotomous outcomes with 95 per cent confidence interval. Heterogeneity was to be investigated including both clinical and methodological factors. Main Results No RCTs were identified. Reviewers' Conclusions There is not appropriate scientific evidence to recommend or discourage the use of prophylactic systemic antibiotics to prevent complications and failures of dental implants. Even though the present review did not assess the effectiveness of prophylactic antibiotics for patients at risk for endocarditis, it seems sensible to recommend the use of prophylactic antibiotics for patients at high and moderate risk for endocarditis, with immunodeficiencies, metabolic diseases, irradiated in the head and neck area and when an extensive or prolonged surgery is anticipated. 相似文献
2.
Evaluation of atypical human immunodeficiency virus immunoblot reactivity in blood donors 总被引:6,自引:0,他引:6
NL Dock ; HV Lamberson Jr ; TA O''Brien ; DE Tribe ; SS Alexander ; BJ Poiesz 《Transfusion》1988,28(5):412-418
Blood donors reactive by enzyme-linked immunosorbent assay for antibody to the human immunodeficiency virus (HIV) who showed atypical patterns of viral core protein reactivity on Western blot were monitored for several months. Characterization of their antibodies was performed by 1) use of recombinant HIV proteins; 2) determination of cross-reactivity to HTLV-I, HTLV-II, and HTLV-IV: 3) assessment of immune status; and 4) identification of potentially interfering autoantibodies. Nineteen of 20 donors maintained the same HIV antibody reactivity throughout the follow-up period; the other donor became fully antibody-positive. Eighteen of 20 donors' sera showed clear reactivity with HIV recombinant core proteins. Ten of 19 donor samples demonstrated cross-reactivity to HTLV-IV; 3 of these 10 also cross-reacted with HTLV-I. The immune status of all donors was normal, although the medical histories and HLA antibody screens suggested possible autoimmune reactivity in 9 of 18 donors. During follow-up interviews, three donors reported possible risk factors for HIV infection that had not been acknowledged at the time of blood donation. We conclude that exclusion of donors with these atypical serologic test results is warranted while further studies to determine significance are being conducted. 相似文献
3.
4.
Bhalachandra?S?KodkanyEmail author Richard?J?Derman Narayan?V?Honnungar Naresh?K?Tyagi Shivaprasad?S?Goudar Shivanand?C?Mastiholi Janet?L?Moore Elizabeth?M?McClure Nancy?Sloan Robert?L?Goldenberg 《Reproductive health》2015,12(Z2):S3
Background
Pregnancy-related vital registration is important to inform policy to reduce maternal, fetal and newborn mortality, yet few systems for capturing accurate data are available in low-middle income countries where the majority of the mortality occurs. Furthermore, methods to effectively implement high-quality registration systems have not been described. The goal of creating the registry described in this paper was to inform public health policy makers about pregnancy outcomes in our district so that appropriate interventions to improve these outcomes could be undertaken and to position the district to be a leader in pregnancy-related public health research.Methods
We created a prospective maternal and newborn health registry in Belgaum, Karnataka State, India. To initiate this registry, we worked with the Ministry of Health to first establish estimated birth rates and define the catchment areas of the clusters, working within the existing health system and primary health centers. We also undertook household surveys to identify women likely to become pregnant. We then implemented monitoring measures to ensure high quality and completeness of the maternal newborn health registry. All pregnant women in the catchment area were identified, consented and enrolled during pregnancy, with follow-up visits to ascertain pregnancy outcomes and mother/infant status at 42-days postpartum.Results
From 2008 through 2014, we demonstrated continued improvements in both the coverage for enrollment and accuracy of reporting pregnancy outcomes within the defined catchment area in Belgaum, India. Nearly 100% of women enrolled had follow-up at birth and 99% had 42-day follow-up. Furthermore, we facilitated earlier enrollment of women during pregnancy while achieving more timely follow-up and decreased time of reporting from the date of the pregnancy event.Conclusions
We created a pregnancy-related registry which includes demographic data, risk factors, and outcomes allowing for high rates of ascertainment and follow-up while working within the existing health system. Understanding the elements of the system used to create the registry is important to improve the quality of the results. Tracking of pregnancies and their outcomes is an important step toward reducing maternal and perinatal mortality.5.
Omrana?PashaEmail author Shivaprasad?S?Goudar Archana?Patel Ana?Garces Fabian?Esamai Elwyn?Chomba Janet?L?Moore Bhalchandra?S?Kodkany Sarah?Saleem Richard?J?Derman Edward?A?Liechty Patricia?L?Hibberd K?Michael?Hambidge Nancy?F?Krebs Waldemar?A?Carlo Elizabeth?M?McClure Marion?Koso-Thomas Robert?L?Goldenberg 《Reproductive health》2015,12(Z2):S11
Background
During the post-partum period, most women wish to delay or prevent future pregnancies. Despite this, the unmet need for family planning up to a year after delivery is higher than at any other time. This study aims to assess fertility intention, contraceptive usage and unmet need for family planning amongst women who are six weeks postpartum, as well as to identify those at greatest risk of having an unmet need for family planning during this period.Methods
Using the NICHD Global Network for Women’s and Children’s Health Research’s multi-site, prospective, ongoing, active surveillance system to track pregnancies and births in 100 rural geographic clusters in 5 countries (India, Pakistan, Zambia, Kenya and Guatemala), we assessed fertility intention and contraceptive usage at day 42 post-partum.Results
We gathered data on 36,687 women in the post-partum period. Less than 5% of these women wished to have another pregnancy within the year. Despite this, rates of modern contraceptive usage varied widely and unmet need ranged from 25% to 96%. Even amongst users of modern contraceptives, the uptake of the most effective long-acting reversible contraceptives (intrauterine devices) was low. Women of age less than 20 years, parity of two or less, limited education and those who deliver at home were at highest risk for having unmet need.Conclusions
Six weeks postpartum, almost all women wish to delay or prevent a future pregnancy. Even in sites where early contraceptive adoption is common, there is substantial unmet need for family planning. This is consistently highest amongst women below the age of 20 years. Interventions aimed at increasing the adoption of effective contraceptive methods are urgently needed in the majority of sites in order to reduce unmet need and to improve both maternal and infant outcomes, especially amongst young women.Study registration
Clinicaltrials.gov (ID# NCT01073475)6.
7.
8.
以乙型肝炎病毒为载体的基因治疗研究 总被引:6,自引:1,他引:6
目的 探讨乙型肝炎病毒(HBV)作为肝靶向性基因治疗载体的可能性。方法 用外源报告基因绿色荧光蛋白(GFP)取代HBV S基因读码框构建重组HBV载体,通过脂质体转染HepG2细胞,荧光显微镜下观察外源基因的表达,半巢式聚合酶链反应(PCR)检测细胞核内HBV 共价闭合环状DNA构型,常规PCR和Southern杂交检测上清液重组病毒DNA。结累 携带外源基因GFP的重组HBV载体能够在肝细胞内表达外源蛋白,此重组载体为复制缺损型,单独转染后不能在肝细胞包装与复制,在缺失包装信号ε的辅助HBV质粒下可被包装成携带外源基因的成熟重组HBV颗粒并分泌到胞外。结论 HBV可被改造成肝靶向性基因治疗载体。 相似文献
9.
Salah Uddin Khan LaShondra Berman Najmul Haider Nancy Gerloff Md Z. Rahman Bo Shu Mustafizur Rahman Tapan Kumar Dey Todd C. Davis Bidhan Chandra Das Amanda Balish Ausraful Islam Jens P. Teifke Nord Zeidner Steven Lindstrom Alexander Klimov Ruben O. Donis Stephen P. Luby H. L. Shivaprasad Andrea B. Mikolon 《Archives of virology》2014,159(3):509-518
We investigated unusual crow mortality in Bangladesh during January-February 2011 at two sites. Crows of two species, Corvus splendens and C. macrorhynchos, were found sick and dead during the outbreaks. In selected crow roosts, morbidity was ~1 % and mortality was ~4 % during the investigation. Highly pathogenic avian influenza virus H5N1 clade 2.3.2.1 was isolated from dead crows. All isolates were closely related to A/duck/India/02CA10/2011 (H5N1) with 99.8 % and A/crow/Bangladesh/11rs1984-15/2011 (H5N1) virus with 99 % nucleotide sequence identity in their HA genes. The phylogenetic cluster of Bangladesh viruses suggested a common ancestor with viruses found in poultry from India, Myanmar and Nepal. Histopathological changes and immunohistochemistry staining in brain, pancreas, liver, heart, kidney, bursa of Fabricius, rectum, and cloaca were consistent with influenza virus infection. Through our limited investigation in domesticated birds near the crow roosts, we did not identify any samples that tested positive for influenza virus A/H5N1. However, environmental samples collected from live-bird markets near an outbreak site during the month of the outbreaks tested very weakly positive for influenza virus A/H5N1 in clade 2.3.2.1-specific rRT-PCR. Continuation of surveillance in wild and domestic birds may identify evolution of new avian influenza virus and associated public-health risks. 相似文献
10.