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   55522篇
  免费   3576篇
  国内免费   109篇
耳鼻咽喉   529篇
儿科学   2296篇
妇产科学   1514篇
基础医学   6946篇
口腔科学   540篇
临床医学   8544篇
内科学   9520篇
皮肤病学   757篇
神经病学   5333篇
特种医学   974篇
外科学   4604篇
综合类   590篇
一般理论   109篇
预防医学   7778篇
眼科学   760篇
药学   3633篇
中国医学   61篇
肿瘤学   4719篇
  2023年   290篇
  2022年   431篇
  2021年   1015篇
  2020年   693篇
  2019年   1050篇
  2018年   1202篇
  2017年   977篇
  2016年   1058篇
  2015年   1237篇
  2014年   1711篇
  2013年   2728篇
  2012年   3929篇
  2011年   4241篇
  2010年   2356篇
  2009年   2127篇
  2008年   3831篇
  2007年   4076篇
  2006年   3927篇
  2005年   4069篇
  2004年   3865篇
  2003年   3636篇
  2002年   3352篇
  2001年   471篇
  2000年   345篇
  1999年   473篇
  1998年   686篇
  1997年   609篇
  1996年   480篇
  1995年   481篇
  1994年   425篇
  1993年   338篇
  1992年   245篇
  1991年   210篇
  1990年   190篇
  1989年   205篇
  1988年   188篇
  1987年   174篇
  1986年   163篇
  1985年   166篇
  1984年   187篇
  1983年   171篇
  1982年   215篇
  1981年   207篇
  1980年   156篇
  1979年   95篇
  1978年   112篇
  1977年   52篇
  1976年   57篇
  1975年   45篇
  1974年   68篇
排序方式: 共有10000条查询结果,搜索用时 170 毫秒
121.
Background. The National Heart, Lung, and Blood Institute (NHLBI) guidelines recommend that patients receive a follow-up outpatient asthma visit after being discharged from an emergency department (ED) for asthma. Objective. To measure the frequency of follow-up outpatient asthma visits and its association with repeat ED asthma visit. Design. We conducted a retrospective cohort study of children with asthma using claims data from a university-based managed care organization from 01 1998 to 10 2000. We performed a multivariate survival analysis using Cox proportional hazards model to determine the effect of follow-up outpatient asthma visits on the likelihood of a repeat ED asthma visit, after controlling for severity of illness, patient age, gender, insurance, and the specialty of the primary care provider. Results: A total of 561 children had 780 ED asthma visits. Of these, 103 (17%) had a repeat ED asthma visit within 1 year. Almost two-thirds of children (66%) did not receive outpatient follow-up for asthma within 30 days of an ED asthma visit. Outpatient asthma visits within 30 days of an ED asthma visit are associated with an increased likelihood (relative risk = 1.80; 95% confidence interval 1.19, 2.72) for repeat ED asthma visits within 1 year. Conclusions. Most patients do not have outpatient follow-up after an ED asthma visit. However, those patients that present for outpatient follow-up have an increased likelihood for repeat ED asthma visits. For the primary care provider, these outpatient follow-up visits signal an increased risk that a patient will return to the ED for asthma and are a key opportunity to prevent future ED asthma visits.  相似文献   
122.
123.
Background: Although managed care organizations (MCOs) may be optimal settings for implementing tobacco use cessation clinical guidelines, such guidelines remain poorly implemented in many MCO settings.Purpose: We examined issues related to the implementation of guidelines in MCOs, to provide examples of studies that have addressed issues related to guideline implementation and to suggest ways behavioral medicine researchers can play a role in examining issues of how guidelines can be better implemented.Methods: Surveys of clinical guideline implementation, studies from the Robert Wood Johnson Foundation addressing tobacco use cessation in a managed care database, selected to illustrate issues related to system-wide implementation.Results: Surveys show that effective tobacco use cessation interventions remain underutilized in MCOs. A few studies have evaluated and shown the benefit of insurance coverage for tobacco use and dependence treatments, clinician reimbursement and leadership incentives, practice feedback, and leveraging administrative data to create tobacco use tracking systems. The studies also point to the need for large-scale, multidisciplinary, methodologically rigorous studies that allow one to isolate the effects of promising strategies as well as to explore synergistic effects as different system changes are combined.Conclusions: Tobacco use cessation guidelines need to be better implemented in MCOs. Behavioral medicine research needs to move beyond treatment efficacy and effectiveness studies to focus on rigorous evaluations of these and other strategies to enhance guideline implementation and dissemination. This research was supported by grants from the Tobacco-Related Disease Research Program (Taylor) and from the Robert Wood Johnson Foundation (Taylor and Curry).  相似文献   
124.
125.
126.
127.
Brain magnetic resonance images (MRI) of 104 healthy childrenand adolescents, aged 4–18, showed significant effectsof age and gender on brain morphometry. Males had larger cerebral(9%) and cerebellar (8%) volumes (P < 0.0001 and P = 0.008.respectively), which remained significant even after correctionfor height and weight After adjusting for cerebral size, theputamen and globus pallidus remained larger in males, whilerelative caudate size was larger in females. Neither cerebralnor cerebellar volume changed significantly across this agerange. Lateral ventricular volume increased significantly inmales (trend for females), with males showing an increase inslope after age 11. In males only, caudate and putamen decreasedwith age (P = 0.007 and 0.05, respectively). The left lateralventricles and putamen were significantly greater than the rightP = 0.01 and 0.0001, respectively). In contrast, the cerebralhemispheres and caudate showed a highly consistent right greater-than-leftasymmetry (P < 0.0001 for both). All volumes demonstrateda high degree of variability. These findings highlight gender-specificmaturational changes of the developing brain and the need forlarge gender-matched samples in pediatric neuropsychiatric studies.  相似文献   
128.
Critical care nurses, ethical decision-making and stress   总被引:2,自引:0,他引:2  
Considerable attention has focused on describing ethical issues that critical care nurses face in their practice; however, less attention has been directed at describing the process of ethical decision-making. Systematic research linking aspects of ethical-decision making and stress is lacking. This cross-sectional study examines the relationship between selected aspects of ethical decision-making, stress and selected nurse characteristics. Sixty-one critical care nurses completed the Nurse's Ethical Decision Making—ICU Questionnaire and the Health Professions Stress Inventory. Findings revealed that nurses who selected the patient advocacy model had significantly higher nurse autonomy scores, that perceived anxiety had a negative association with nurse autonomy, and that workplace restrictions and stress were related.  相似文献   
129.
In this study, ethnographic interviews were used to identify first-time fathers' experiences of the birth of their first child. Fourteen fathers were interviewed, and prenatal expectations of the experience are compared with the fathers' perceptions after the birth. Although the fathers expected to be treated as part of a laboring couple, they found that they were relegated to a supporting role. Initially the fathers were confident of their ability to support their wives, but they found that labor was more work than they had anticipated. They became fearful of the outcome, but hid these fears from their partners. Later, they found that their focus moved from their wives to their babies at the time of birth. The men all completed the experience with an enhanced respect for their wives. Fathers should be included in labor management plans and need support for their role as coach, particularly when their wives experience pain. They also need to be encouraged to eat and take a break from their wives' labor when appropriate.  相似文献   
130.
Changes in intracellular pH (pHi) are thought to produce large changes in force production in the uterus. There have however, been no simultaneous measurements of pHi and force in the uterus and therefore no direct information is available about the relation between the two. We have used carboxy-SNARF (a pH-sensitive fluorophore) in small strips of longitudinal myometrium and obtained simultaneous measurements of pHi and force. SNARF did not alter contractile function, and continuous measurements of pHi could be made for 2 hours. The mean resting pHi (7.16) was similar to that reported previously. Application of weak bases rapidly raised pHi, in a concentration-dependent manner, followed by a gradual restoration of pHi to resting levels. Alkalinization greatly increased the frequency of contractions, often accompanied by a small increase in their amplitude. Removal of base produced a rebound acidification which transiently abolished contractions. Direct acidification of the cytoplasm, by application of weak acid, also abolished contractions. However the alkalinization which accompanied removal of acid, produced variable effects on force.Supported by the M.R.C.  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