首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1818篇
  免费   148篇
  国内免费   4篇
耳鼻咽喉   14篇
儿科学   71篇
妇产科学   56篇
基础医学   200篇
口腔科学   20篇
临床医学   350篇
内科学   298篇
皮肤病学   24篇
神经病学   168篇
特种医学   31篇
外科学   213篇
综合类   17篇
一般理论   5篇
预防医学   253篇
眼科学   12篇
药学   112篇
中国医学   5篇
肿瘤学   121篇
  2023年   17篇
  2022年   10篇
  2021年   39篇
  2020年   31篇
  2019年   54篇
  2018年   61篇
  2017年   49篇
  2016年   50篇
  2015年   47篇
  2014年   80篇
  2013年   117篇
  2012年   123篇
  2011年   143篇
  2010年   86篇
  2009年   77篇
  2008年   120篇
  2007年   125篇
  2006年   107篇
  2005年   110篇
  2004年   100篇
  2003年   74篇
  2002年   85篇
  2001年   13篇
  2000年   11篇
  1999年   26篇
  1998年   33篇
  1997年   17篇
  1996年   11篇
  1995年   9篇
  1994年   11篇
  1993年   11篇
  1992年   10篇
  1991年   7篇
  1990年   5篇
  1989年   11篇
  1988年   4篇
  1987年   8篇
  1985年   5篇
  1984年   4篇
  1983年   5篇
  1981年   4篇
  1980年   5篇
  1979年   5篇
  1978年   5篇
  1977年   6篇
  1974年   3篇
  1972年   3篇
  1971年   6篇
  1969年   3篇
  1964年   3篇
排序方式: 共有1970条查询结果,搜索用时 106 毫秒
1.
Over 36 million people worldwide are infected with HIV. Antiretroviral therapy (ART) has proven to be highly effective to prevent HIV-1 transmission, clinical progression and death. Despite this success, the number of HIV-1 infected individuals continues increasing and ART should be taken for life. Therefore, there are two main priorities: the development of preventive vaccines to protect from HIV acquisition and achieve an efficient control of HIV infection in the absence of ART (functional cure). In this sense, in the last few years, there has been a broad interest in new and innovative approaches such as mRNA-based vaccines. RNA-based immunogens represent a promising alternative to conventional vaccines because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration. Some mRNA-based vaccines platforms against infectious diseases have demonstrated encouraging results in animal models and humans. However, their application is still limited because the instability and inefficient in vivo delivery of mRNA. Immunogens, design, immunogenicity, chemical modifications on the molecule or the vaccine delivery methods are all crucial interventions for improvement. In this review we, will present the current knowledge and challenges in this research field. mRNA vaccines hold great promises as part of a combined strategy, for achieving HIV functional cure.  相似文献   
2.
Fetal scalp blood sampling (FSBS), in conjunction with fetal heart rate monitoring, is a method of fetal surveillance that may avoid cesarean delivery of the healthy fetus or indicate the need for immediate delivery of a compromised fetus. Some researchers have recently begun to question the efficacy of FSBS. In this article, three nurse-midwives discuss FSBS as a tool in assessing fetal well-being during labor and consider whether FSBS is a nurse-midwifery procedure.  相似文献   
3.
Immunologic and pharmacologic concepts of monoclonal antibodies   总被引:2,自引:0,他引:2  
While monoclonal antibodies have solved many of the difficulties of using immunologic reagents for radioimmunodiagnosis and therapy, in the 13 years since their introduction a number of persistent problems remain, most notably a low yield of antibody-producing cells from the fusion process, difficulty in obtaining high-affinity antibodies, and the potential immunogenicity of murine immunoglobulins (Igs). Several solutions are under development, including fusion techniques that enrich for cells producing desired antibodies, production of human-mouse chimeric antibodies by recombinant DNA technology, and the generation of human monoclonal antibodies by promising new approaches. Until these upcoming methodologies are established, and to better direct their development and application, a sound understanding of the pharmacology of presently available native and modified monoclonal antibodies is crucial. Although much has been already determined in this area, a great deal of further clarification remains necessary.  相似文献   
4.
Background: This is the second of two papers using qualitative methods from a study of an intervention for family members affected by close relatives' substance misuse problems.

Participants: 168 primary healthcare professionals (PHCPs: GPs, practice nurses and health visitors) working in general practices in two areas of England, and who took part in the study.

Data sources: Recruitment and post-session forms completed by PHCPs; telephone interviews with each PHCP 12 weeks after recruitment of a family member; interviews with PHCPs at the end of the study.

Results: At the end of the project PHCPs were overwhelmingly positive about the family member intervention and about primary care as the appropriate site. Difficulties were encountered, however, in identifying and engaging affected family members, who were often excluded on grounds of the complexity of their problems or the level of their distress. Shortage of PHCP time and other practice-related factors added to the difficulty. Active work by a PHCP was often necessary in order to make the link between presenting symptoms of physical or mental ill-health and the existence of a family substance misuse problem. When family members were identified and recruited, PHCPs were usually positive about what was achieved. Nearly all were in favour of an approach that combined giving a self-help manual with some follow-up contact with a family member as needed.

Conclusions: Taken in conjunction with statistical outcome findings of significant reductions in symptoms and changes in ways of coping, plus qualitative analysis of the views of family members, the present results encourage the view that a flexible form of this intervention should be developed for use in primary healthcare, and that further work should build on existing strengths and attempt to overcome weaknesses identified.  相似文献   
5.
Government reform of the NHS in the UK has sought to increase the involvement of doctors (clinicians) in hospital management. Using frameworks from the psychological contract and organisational misbehaviour literatures, this paper examines the processes involved when clinicians assume management roles. This literature seeks to explain breaches to expectations regarding prior agreements with management and subsequent actions of 'getting even' as a result of breaches to the employment relationship. A qualitative methodology using interviews was undertaken, which identified two distinct groups of clinician-manager. Investors actively pursued a management opportunity as an alternative to clinical medicine, whilst reluctants tended to assume a management role to protect particular specialities from outside influence or from those they thought would be inappropriate clinician-managers. Investors and reluctants often had very little prior experience of management and managers and had problems reconciling their dual clinician-management role. Poor relationships with hospital managers who often had no understanding of their dual responsibilities led to tensions and conflict, which questions continued developments in this important area of UK health policy. Suggestions for improving this process are outlined.  相似文献   
6.
7.
8.
The study reports the pre-post findings from a controlled comparative evaluation of treatments for bulimia nervosa. These pre-post results allow comparison of the hypnobehavioural and cognitive behavioural treatments with a waiting list control group and a comparison of the immediate effects of the two modalities. One hundred and thirty subjects were screened to enter the study. Seventy-eight subjects entered the investigation after being randomly allocated to either a waiting list control group, or to hypnobehavioural or cognitive behavioural groups. The treatments were delivered individually and matched in duration (8 weeks) and the number of sessions. Pre to posttreatment outcome indicated significant differences between the control group and the two treatments in reductions in bulimic behaviours and related eating pathology. The immediate effects of both treatments were equal. There were no differences at posttreatment between the treatments in abstinence from either bingeing or purging. The treatment effects were also similar to the immediate effects obtained by longer therapeutic approaches.  相似文献   
9.
OBJECTIVE: We performed a prospective, randomized clinical trial to compare the usefulness of the minute ventilation test (MVT) with clinical judgement in predicting readiness for extubation in preterm newborns with respiratory distress syndrome requiring surfactant therapy and mechanical ventilation. STUDY DESIGN: A total of 42 preterm infants with respiratory distress syndrome were randomized when they reached preselected ventilator settings. The primary outcome measure was the time from study entry to extubation, provided the infant remained extubated for at least 24 hours. RESULTS: Infants evaluated by the MVT were extubated in a significantly shorter period of time (mean of 8 hours) than those evaluated clinically (mean of 36 hours). The extubation failure rate was similar in the two groups. CONCLUSION: The MVT is an easily performed objective measure that can be used to predict readiness for extubation in preterm infants. In this study, it significantly shortened the time for extubation and was not associated with a higher rate of reintubation.  相似文献   
10.
A diagnosis of cyclosporiasis typically involves stool examinations for the presence of Cyclospora oocysts by means of microscopy. In recent years, flow cytometry has been gaining in popularity as a novel method of detecting pathogens in environmental and clinical samples. The present study is an evaluation of a flow cytometric method for the detection and enumeration of Cyclospora oocysts in human fecal specimens associated with food-borne outbreaks of cyclosporiasis in Ontario, Canada. Flow cytometry results were generally very comparable to the original microscopy results for these specimens, in terms of both presence or absence of oocysts and relative oocyst concentrations. Of the 34 fecal specimens confirmed positive for Cyclospora by microscopy, 32 were also found positive by flow cytometry, and 2 others were considered equivocal. Of the eight fecal specimens reported to be negative by microscopy, two were found positive by flow cytometry and five others were considered equivocal. These two flow cytometry-positive samples and one of the equivocal samples were confirmed by microscopic reexamination, suggesting that flow cytometry may be more sensitive than microscopy. While the sample preparation time for flow cytometry is similar to or slightly longer than that for microscopy, the actual analysis time is much shorter. Further, because flow cytometry is largely automated, an analyst's levels of fatigue and expertise will not influence results. Flow cytometry appears to be a useful alternative to microscopy for the screening of large numbers of stool specimens for Cyclospora oocysts, such as in an outbreak situation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号