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   745篇
  免费   73篇
  国内免费   5篇
儿科学   20篇
妇产科学   2篇
基础医学   66篇
口腔科学   4篇
临床医学   95篇
内科学   188篇
皮肤病学   20篇
神经病学   90篇
特种医学   108篇
外科学   47篇
综合类   25篇
预防医学   58篇
药学   74篇
中国医学   1篇
肿瘤学   25篇
  2019年   7篇
  2017年   7篇
  2016年   9篇
  2015年   13篇
  2014年   13篇
  2013年   23篇
  2012年   31篇
  2011年   24篇
  2010年   12篇
  2009年   19篇
  2008年   27篇
  2007年   30篇
  2006年   27篇
  2005年   25篇
  2004年   31篇
  2003年   20篇
  2002年   32篇
  2001年   17篇
  2000年   17篇
  1999年   12篇
  1998年   17篇
  1997年   26篇
  1996年   14篇
  1995年   21篇
  1994年   14篇
  1993年   10篇
  1992年   14篇
  1991年   12篇
  1990年   16篇
  1989年   21篇
  1988年   21篇
  1987年   14篇
  1986年   17篇
  1985年   10篇
  1984年   9篇
  1980年   10篇
  1979年   11篇
  1978年   11篇
  1977年   19篇
  1976年   10篇
  1975年   13篇
  1974年   8篇
  1973年   9篇
  1972年   10篇
  1971年   7篇
  1970年   8篇
  1969年   9篇
  1967年   14篇
  1966年   7篇
  1965年   5篇
排序方式: 共有823条查询结果,搜索用时 15 毫秒
51.
To synthesise the evidence relating to the effectiveness of advice, the relevance of its content and frequency, and to compare the advice being offered to acute, subacute and chronic low back pain (LBP) patients. A systematic review of Randomised Controlled Trials (RCTs) using advice, either alone or with another intervention. The QUOROM guidelines and the Cochrane Collaboration Back Review Group Guidelines for Systematic Reviews were followed throughout: methodological assessment identified RCTs of ‘high’ or ‘medium’ methodological quality, based on their inclusion of at least 50% of the specified internal validity criteria. Outcome measures were analysed based on five recommended core outcome domains; pain, work disability, back-specific function, generic health status and satisfaction with care. Relevant RCTs (n=56) were scored for methodological quality; 39 RCTs involving 7347 patients qualified for inclusion, based upon their methodological quality. Advice as an adjunct to exercise was most effective for improving pain, back-specific function and work disability in chronic LBP but, for acute LBP, was no more effective for improving these outcomes than simple advice to stay active. Advice as part of a back school was most effective for improving back-specific function in subacute LBP; these trials generally demonstrated long-term positive results. Advice as an adjunct to exercise was the most common form of treatment for acute and chronic LBP; advice as part of a back school was most commonly used for subacute LBP. Fifteen percent of acute LBP trials had a positive outcome, compared to 86% and 74% of subacute and chronic LBP trials respectively. A wide variety of outcome measures were used, making valid comparisons between treatment outcomes difficult. The advice provided to patients with LBP within RCTs varied considerably depending on symptom duration. The findings of this review have important implications for clinical practice, and for the design of further clinical trials in this area. Advice to stay active is sufficient for acute LBP; however, it appears that RCTs do not commonly reflect these recommendations. No conclusions could be drawn as to the content and frequency of advice that is most effective for subacute LBP, due to the limited number and poor quality of RCTs in this area: this review provides preliminary support for advice as part of a back school approach. Given that the effectiveness of treatment for subacute symptoms will directly influence the development of chronicity, these results would suggest that education and awareness of the causes and consequences of back pain may be a valuable treatment component for this patient subgroup. For chronic LBP there is strong evidence to support the use of advice to remain active in addition to specific advice relating to the most appropriate exercise, and/or functional activities to promote active self-management. More investigation is needed into the role of follow-up advice for chronic LBP patients.  相似文献   
52.
53.
Regulation of gastric emptying in humans by cholecystokinin.   总被引:13,自引:2,他引:13       下载免费PDF全文
In the present study we used a bioassay system for measuring plasma cholecystokinin (CCK) to evaluate whether CCK has a physiologic role in regulating gastric emptying in humans. Plasma CCK levels and gastric emptying after ingestion of a mixed liquid meal were determined in five normal male volunteers. Fasting CCK levels averaged 0.8 +/- 0.1 pM and increased to 6.5 +/- 1.0 pM within 10 min of drinking the mixed meal. CCK levels remained elevated for up to 90 min. Gastric emptying after a meal was slow; at the end of the 90 min 68% of the original volume remained in the stomach. The rate of gastric emptying of water was then measured in the same individuals with a simultaneous infusion of either saline, or one of two doses of CCK (12 pmol/kg per h and 24 pmol/kg per h). With the saline infusion, plasma CCK levels did not increase above basal and gastric contents emptied rapidly. At the end of 90 min only 7% of the original volume remained in the stomach. The lower dose of CCK resulted in a plasma level of 3.4 pM which both reproduced the average postprandial plasma level and caused a significant delay in gastric emptying. The higher dose of CCK achieved plasma levels of 8 pM and resulted in a delay in gastric emptying that was similar to that seen with the mixed meal. Since exogenous CCK at concentrations which occur postprandially delays gastric emptying, we conclude that CCK is a physiologic regulator of gastric emptying.  相似文献   
54.
55.
The blood pressure elevation of primary aldosteronism is caused by excessive production of the known mineralocorticoid, aldosterone. The blood pressure elevation of low-renin essential hypertension may also be caused by mineralocorticoid excess, but which which mineralocorticoid is responsible is uncertain. Normal levels of aldosterone, found in this disorder despite suppressed plasma renin, and the presence of an unknown mineralocorticoid have been hypothesized to explain low-renin essential hypertension. We contrasted the blood pressure responses and changes in aldosterone seen in patients with low-renin essential hypertension and primary aldosteronism during treatment with two adrenal enzyme inhibitors. The results demonstrate the similarity between decrease in blood pressure and in aldosterone during early adrenal inhibition in both primary aldosteronism and in low-renin essential hypertension. During treatment with a distal adrenal blocker, patients with primary aldosteronism demonstrated decreases in both aldosterone and blood pressure, whereas patients with low-renin essential hypertension showed a decrease in aldosterone without significant change in blood pressure. This suggested that aldosterone was not the major mineralocorticoid responsible for low-renin essential hypertension. Unknown mineralocorticoid excretion decreased (along with blood pressure) during early inhibition but failed to decrease (along with blood pressure) during late inhibition at a time when aldosterone excretion decreased. This suggests that unknown mineralocorticoids play significant roles in the blood pressure elevation of low-renin essential hypertension.  相似文献   
56.
A retrospective review of patients receiving rituximab off label in a large teaching hospital was conducted between July 2002 and January 2006. The indication, dosing regimen, efficacy and cost of rituximab were evaluated. Rituximab was prescribed for three clinical indications; acute organ transplant rejection, post-transplant lymphoproliferative disease and autoimmune disease. On average, 600 mg of rituximab was prescribed weekly for 4 weeks, costing the hospital $108,739.37. We suggest an initial approval for a limited number of doses with subsequent approval dependent on improvement in predefined clinical or biochemical end-points. Furthermore, we suggest an Australia-wide central database be established to enable delineation of the optimal dosing schedule, as well as monitoring of clinical outcome.  相似文献   
57.
BACKGROUND/OBJECTIVES: The very elderly constitute a subgroup of elderly who may respond differently than the younger elderly to medical intervention. This possibility has not previously been investigated. Our study investigates whether successful rehabilitation of the very elderly is possible within the current processes of care and also whether factors that help predict successful rehabilitation in all age elderly are applicable to the oldest old. METHODS: A retrospective case note analysis of all very elderly people (>or=90 years old) treated within in-patient elderly person rehabilitation facilities at the Northern General Hospital, Sheffield. Potential predictive factors analysed: Barthel index, main presenting illness, number of co-morbid conditions, number of regular prescribed medications, abbreviated mental test score, prior formal social services input, previous hospital admission within 1 year and serum albumin (g/l). Outcome measures reflecting success of rehabilitation: duration of rehabilitation (days), discharge destination to the same ('good outcome') or increased ('poor outcome') level of social and/or nursing care, readmission to hospital within 30 days of discharge and death during rehabilitation or within 120 days of discharge. RESULTS: Of 230 nonagenarians admitted to inpatient elderly rehabilitation 47% required no increase in social support following their admission and 76% of those admitted from their own home were able to return there. Barthel index and the number of co-morbid conditions were the most influential predictors of success, with Barthel index predicting length of stay (p < 0.001), discharge destination (p < 0.001) and in-hospital mortality (p < 0.01) and co-morbidity predicting readmission to hospital (p = 0.05), in-hospital mortality (p = 0.04) and survival (p = 0.05). On multi-variate analysis all other predictive factors analysed, except for presenting illness, were associated with at least one outcome measure (p < 0.05). CONCLUSION: Successful inpatient rehabilitation of the very elderly is possible. Factors that predict the success of rehabilitation of nonagenarians are similar to those associated with success in the younger elderly. The factors that most broadly predict success are Barthel index and the number of co-morbid conditions identified at admission to rehabilitation. Main presenting illness did not emerge as a predictor within this group.  相似文献   
58.
This study examines EEG low frequency characteristics which have been linked to specific cognitive functions such as stimulus encoding and attention during an auditory oddball task in schizophrenia patients and healthy controls. EEG data was recorded from 17 young schizophrenia patients in a stable phase of their illness and 17 healthy controls performing an auditory oddball task. Evoked and induced delta and theta activity, N100, P300 amplitude were computed. Between 200–500 ms after a stimulus was presented, patients displayed significantly reduced P300, less evoked and induced delta and theta activity than controls. We conclude that the well known finding of P300 reduction in schizophrenia can be linked to reductions in delta and theta activity, which are a manifestation of impaired stimulus evaluation, memory retrieval, and a lack of sustained attention.  相似文献   
59.
Background/aims:  This study investigated the time use, role participation and life satisfaction of older Australians (aged 65 years and older) who were 1–3 years post-stroke and living in the community. The results of this study were compared with a published study on the time use, role participation and life satisfaction of older Australians who had not experienced stroke.
Methods:  Twenty-three participants with stroke (mean age 74.2 years, 69.6% men) were interviewed using measures of time use, role participation and life satisfaction.
Results:  Participants with stroke spent most of their time in sleep (7.2 h/day), solitary leisure (7.0 h/day), social leisure (3.0 h/day), and basic activities of daily living (2.9 h/day). Compared to the sample without stroke, participants with stroke spent significantly less time in sleep, instrumental activities of daily living, and volunteer work, and significantly more time at home, with others, and engaged in solitary leisure. Similar to the sample without stroke, the most common roles for participants with stroke were family member, friend, and home maintainer. Participants with stroke engaged in fewer roles than participants without stroke. Unlike the sample without stroke, role loss was not correlated with life satisfaction for participants with stroke; however, having more roles was correlated with greater life satisfaction.
Conclusion:  Experiencing a stroke can affect the configuration of older people's time use and reduce their role participation. Facilitation of older people's role participation after stroke may enhance their life satisfaction.  相似文献   
60.
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