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   18344篇
  免费   1338篇
  国内免费   44篇
耳鼻咽喉   176篇
儿科学   632篇
妇产科学   500篇
基础医学   2501篇
口腔科学   195篇
临床医学   2201篇
内科学   3422篇
皮肤病学   323篇
神经病学   1947篇
特种医学   492篇
外国民族医学   5篇
外科学   1967篇
综合类   138篇
一般理论   14篇
预防医学   2247篇
眼科学   269篇
药学   1192篇
中国医学   13篇
肿瘤学   1492篇
  2024年   34篇
  2023年   244篇
  2022年   457篇
  2021年   835篇
  2020年   443篇
  2019年   799篇
  2018年   865篇
  2017年   608篇
  2016年   651篇
  2015年   700篇
  2014年   937篇
  2013年   1080篇
  2012年   1675篇
  2011年   1662篇
  2010年   826篇
  2009年   700篇
  2008年   1143篇
  2007年   1130篇
  2006年   1017篇
  2005年   950篇
  2004年   864篇
  2003年   675篇
  2002年   614篇
  2001年   61篇
  2000年   62篇
  1999年   60篇
  1998年   131篇
  1997年   88篇
  1996年   69篇
  1995年   52篇
  1994年   52篇
  1993年   41篇
  1992年   24篇
  1991年   20篇
  1990年   8篇
  1989年   13篇
  1988年   17篇
  1987年   12篇
  1986年   9篇
  1985年   9篇
  1984年   9篇
  1983年   9篇
  1982年   8篇
  1981年   8篇
  1980年   11篇
  1978年   5篇
  1977年   5篇
  1976年   13篇
  1973年   3篇
  1972年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
It is well established that the circadian clock of the suprachiasmatic nuclei (SCN) is entrained by light. More recently, the potent effects of arousing, non-photic cues on the clock have been recognized. The neural mediators of non-photic entrainment are yet to be identified. To examine the contribution of the thalamic intergeniculate leaflet (IGL) and its NPY-immunopositive projection, the geniculo-hypothalamic tract to non-photic entrainment by arousal, male Syrian hamsters received lesions of the IGL (IGLX) which ablated NPY-immunoreactivity in the SCN. Their circadian responses to both photic and non-photic cues were then tested. Lesions resulted in a delay in the timing of activity onset following lights out, but had no effect on the behavioural or cellular circadian responses to phase-advancing light pulses presented at circadian time (CT) CT19 (where CT12 represents the time of activity onset). Injection with a benzodiazepine (chlordiazepoxide, 100 mg/kg) at CT6 suppressed wheel-running, increased general locomotion of intact controls and induced large phase advances of the circadian rhythm of wheel-running. Chlordiazepoxide also inhibited wheel-running in lesioned animals, but there was no significant increase in general locomotion and the lesioned animals did not phase advance. Serial arousal by injection of saline at intervals of 23.5 h for 6 days entrained the circadian rhythm of wheel-running of intact hamsters and was associated with an increase in general locomotor activity. Entrainment by serial arousal was abolished by IGLX. However, the lesioned animals did show a clear behavioural response to every presentation of the non-photic cue. These results show that the IGL is a necessary component of the neural pathways mediating both arousal- and benzodiazepine-induced non-photic entrainment.  相似文献   
12.
13.
ABSTRACT:Background: In 1996 a new model of maternity care characterized by continuity of midwifery care from early pregnancy through the postpartum period was implemented for women attending Monash Medical Centre, a tertiary level obstetric service, in Melbourne, Australia. This study's purpose was to assess the impact of this model on women's views and experiences of care during the antenatal, intrapartum, and postpartum periods compared with views of women receiving standard maternity care. Methods: One thousand low‐ and high‐risk women who booked at the antenatal clinic and met the eligibility criteria were randomly allocated to continuity of midwifery care from a group of seven midwives in collaboration with medical staff, or to standard care from a variety of midwives and medical staff. Women's views of care were measured by means of a postal questionnaire at four months after the birth. Results: Team midwifery care was associated with increased satisfaction with antenatal, intrapartum, and some aspects of postpartum care. The differences were most obvious for antenatal care. Conclusions: Continuity of midwifery care is realistically achievable in a tertiary obstetric referral service and is associated with increased satisfaction. (BIRTH 30:1 March 2003)  相似文献   
14.
Study Objective . To determine if one commercial extended-release formulation of nifedipine (Adalat CC) is as effective as another (Procardia XL) in controlling blood pressure over 24 hours. Design . Open-label, randomized, crossover study. Setting . University-affiliated family medicine clinic. Patients . Fifteen patients with stage 1–4 primary hypertension. Interventions . Procardia XL or Adalat CC once/day was titrated to achieve blood pressure control. The effective dose was continued for 4 weeks, washed out for 1 week, and reinstituted with other study drug. Measurements and Main Results . Twenty-four-hour ambulatory blood pressure was recorded the conclusion of each treatment phase. Treatment phases were compared for mean 24-hour blood pressure, mean daytime (6:00 a.m.–10:00 p.m.) and mean nighttime blood pressure, and mean blood pressure load (percentage of blood pressure measurements < 140/90 mm Hg daytime and > 120/80 mm Hg nighttime). Thirteen patients completed the study. No statistically significant difference was seen in mean 24-hour blood pressure (138/86 mm Hg for Procardia XL vs 137/85 mm Hg for Adalat CC), daytime or nighttime blood pressure, or blood pressure load. Two patients experienced clinically significant adverse effects while taking Adalat CC. Conclusions . In these patients with primary hypertension, Adalat CC was as effective as Procardia XL at controlling blood pressure for 24 hours. Blood pressure, heart rate, and adverse effects should be monitored 2–4 weeks after any exchange of Adalat CC for Procardia XL.  相似文献   
15.
16.
17.
ABSTRACT: Managed care organizations (MCOs) joined local and state public health agencies in a pilot effort to improve hepatitis B immunization rates of adolescents in an urban and a suburban/rural school district. The pilot also explored issues inherent in public and private collaboration on population health improvement.
Local public health agencies provided links to schools in their communities, took the lead in implementing school-based immunization programs, and provided health education materials. MCOs contributed financial support necessary for the project. The final cost per fully vaccinated student, not taking into account the work group's planning and coordination time, was little more than the catalog price of the vaccine alone.
Managed care organizations face challenges that complicate their participation and funding of school-based vaccinations: 1) Limited data on health plans of participating students complicate allocation of costs to each MCO; 2) Double-paying occurs for MCOs paying clinics a monthly, per-member rate that already includes adolescent immunizations; 3) When schools provide adolescent immunizations, MCOs lose the "hook" that draws adolescents to clinics for comprehensive health services.
When self-consenting is permitted, schools can achieve a high consent and completion rates for multi-dose adolescent immunizations such as hepatitis B. At the same time, MCOs have the responsibility to provide members with comprehensive care and should continue to examine both internal modifications and external partnerships as opportunities to improve their services to adolescents.  相似文献   
18.
The value of positron emission tomography using [18F]-fluoro-deoxy-glucose (FDG-PET) for pretherapeutic evaluation of patients with non-small cell lung cancer (NSCLC) is beyond doubt. Due to the increasing availability of PET and PET-CT scanners the method is now widely available, and its technical integration has become possible for radiotherapy planning systems. Due to the depiction of malignant tissue with high diagnostic accuracy, the use of FDG-PET in radiotherapy planning of NSCLC is very promising. However, by uncritical application, PET could impair rather than improve the prognosis of patients. Therefore, in the present paper we give an overview of technical factors influencing PET and PET-CT data, and their consequences for radiotherapy planning. We further review the relevant literature concerning the diagnostic value of FDG-PET and on the integration of FDG-PET data in RT planning for NSCLC. We point out the possible impact in gross tumor volume (GTV) definition and describe methods of target volume contouring of the primary tumor, as well as concepts for the integration of diagnostic information on lymph node involvement into the clinical target volume (CTV), and the possible implications of PET data on the definition of the planning target volume (PTV). Finally, we give an idea of the possible future use of tracers other than [18F]-FDG in lung cancer.  相似文献   
19.
20.
Fashion parades, balls, raffles, and weekly deductions from thousands of workers' pay packets were integral to success of the Cancer Appeal-a-thon in the Illawarra region. In 1986–87 the Illawarra community was induced to contribute $1.5 million in order to purchase a linear accelerator for the Wollongong Hospital. The community agreed that a radiotherapy machine was the number one health service priority for the region. Or did it? Application of Alford's structural interests framework to this case-study reveals how failure to examine power relations between medical monopolizers, health care rationalizers and community participants results in an inability to recognise that alternative community needs — for cancer prevention, domiciliary care, or alternative therapies — might be unarticulated or unobservable, and in an inability to ask whether the community may be mistaken about, or unaware of, its own health needs. Specifically, the paper argues that, ‘community needs’ are easily manipulated or distorted by powerful interest groups and that the political context within which community needs are recognized, articulated and mobilized is the most important issue for community participation in the health policy-making process.  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