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   4567篇
  免费   199篇
  国内免费   12篇
耳鼻咽喉   30篇
儿科学   174篇
妇产科学   63篇
基础医学   549篇
口腔科学   169篇
临床医学   590篇
内科学   683篇
皮肤病学   24篇
神经病学   516篇
特种医学   122篇
外科学   577篇
综合类   26篇
一般理论   1篇
预防医学   426篇
眼科学   16篇
药学   347篇
肿瘤学   465篇
  2021年   32篇
  2020年   35篇
  2019年   49篇
  2018年   62篇
  2017年   56篇
  2016年   58篇
  2015年   57篇
  2014年   94篇
  2013年   177篇
  2012年   244篇
  2011年   219篇
  2010年   151篇
  2009年   129篇
  2008年   290篇
  2007年   300篇
  2006年   289篇
  2005年   321篇
  2004年   272篇
  2003年   290篇
  2002年   268篇
  2001年   68篇
  2000年   38篇
  1999年   52篇
  1998年   73篇
  1997年   78篇
  1996年   66篇
  1995年   55篇
  1994年   48篇
  1993年   41篇
  1992年   40篇
  1991年   43篇
  1990年   32篇
  1989年   30篇
  1988年   38篇
  1987年   31篇
  1986年   37篇
  1985年   39篇
  1984年   40篇
  1983年   46篇
  1982年   50篇
  1981年   42篇
  1980年   36篇
  1979年   29篇
  1978年   30篇
  1977年   32篇
  1976年   22篇
  1975年   29篇
  1974年   21篇
  1968年   23篇
  1967年   24篇
排序方式: 共有4778条查询结果,搜索用时 31 毫秒
1.
Patients have become increasingly well informed with higher expectations to be involved in decision-making processes regarding their care and treatment. However, few studies have examined the impact of patient involvement on health care providers’ partnership-building communication. The aim of this study was to measure and explore the self-reported effects of patient involvement on the work of physicians and nurses. A questionnaire survey was distributed among cardiology staff in 12 Swedish hospitals (N = 488, response rate 67%). The sample was comprised of registered nurses (RNs, n = 303), licensed practical nurses (LPNs, n = 132), and physicians (MDs, n = 53). Confirmatory factor analysis was used to examine seven questionnaire statements concerning implications of patient involvement for one’s clinical work. Regression analyses were used to examine factors associated with staff’s partnership-building communication. Analysis confirmed two distinct factors accounting for 57% of the total variance, representing both negative—“Hassles”and positive—“Uplifts”aspects of patient involvement. Regression analyses revealed that only positive aspects (i.e., uplifts) of patient involvement predicted staff behavior aimed at involving patients. Working with actively involved patients may be a source of stress, both negative and positive, for health care professionals. By developing work routines for involving patients in their care, health care workplaces may help health care professionals to buffer the negative effects, and enhance the positive effects, of that stress.  相似文献   
2.
3.
4.
5.
BACKGROUND: Dialysis patient mortality remains high, and this high mortality may be due to many factors. In peritoneal dialysis (PD) patients, old age, co-morbid diseases, malnutrition, low residual renal function (RRF) and a high peritoneal transport rate have been shown to influence survival, but the relative importance of these factors may differ between different patient populations. Besides, centre practice patterns may differ between centres and may influence patient survival. In addition, the literature suggests that dialysis patient survival may be better in Asian than in Caucasian patients. METHODS: The influence of centre and patient characteristics on patient survival was investigated in 132 Korean and 106 Swedish incident PD patients, who underwent initial biochemical measurements and assessment of adequacy of dialysis, nutritional status, RRF and peritoneal transport characteristics. RESULTS: At the start of PD, Korean patients had a higher prevalence of diabetes, peritoneal Kt/V(urea), peritoneal creatinine clearance and peritoneal fluid removal, and lower body mass index, RRF and dialysate to plasma creatinine concentration ratio (D/P Cr) compared with Swedish patients. Significantly more patients from Korea were placed on temporary haemodialysis before PD (100 out of 132) when compared with Swedish patients (21 out of 106). During the follow-up, there was a significantly higher rate of transfer to other units in Korea and a significantly higher rate of kidney transplantation in Sweden. On Kaplan-Meier analysis, overall patient survival did not differ and relative risk for death was also not different between the two centres even after adjustment for age, diabetes, cardiovascular disease, RRF and D/P Cr. On Cox proportional hazards multivariate analysis, age, diabetes, RRF and D/P Cr were found to be independent predictors of mortality in the combined cohort of patients. While age, diabetes and D/P Cr were independent predictors of mortality in Korean patients, age and RRF independently predicted mortality in Swedish patients. CONCLUSION: Although there were significant differences in centre and patient characteristics, we were unable to confirm a survival advantage for Korean over Swedish PD patients. The results of this study suggest that the reported difference in survival between Asian and Caucasian dialysis patients may have been due, in part, to differences in centre and patient characteristics rather than to race as such. The genetic influence on patient characteristics remains, however, to be elucidated.  相似文献   
6.
The relationship between the bioenergetic status of human glioma xenografts in nude mice and morphometric parameters of the perfused vascular architecture was studied using (31)P magnetic resonance spectroscopy (MRS), fluorescence microscopy and two-dimensional digital image analysis. Two tumour lines with a different vascular architecture were used for this study. Intervascular distances and non-perfused area fractions varied greatly between tumours of the same line and tumours of different lines. The inorganic phosphate-nucleoside triphosphate (P(i)/NTP) ratio increased rapidly as mean intervascular distances increased from 100 microm to 300 microm. Two morphometric parameters - the percentage of intervascular distances larger than 200 microm (ivd200) and the non-perfused area fraction at a distance larger than 100 microm from a nearest perfused vessel (area100), - were deduced from these experiments and related to the P(i)/NTP ratio of the whole tumour. It is assumed that an aerobic to anaerobic transition influences the bioenergetic status, i.e. the P(i)/NTP ratio increased linearly with the percentage of ivd200 and the area100.  相似文献   
7.
8.
We evaluated the diagnostic performance of 15 clinical case definitions for pertussis in 233 patients who developed acute respiratory illness during community outbreaks in Wisconsin and Delaware. Using results from culture (Regan-Lowe media) and serology (Ig-class-specific ELISA) as diagnostic standards, cough for greater than or equal to 14 days was both sensitive (84 per cent-92 per cent) and specific (63 percent-90 per cent) in identifying patients with pertussis. This definition may be useful in monitoring pertussis outbreaks and for investigating contacts of culture-positive cases.  相似文献   
9.
For a PET agent to be successful as a biomarker in early clinical trials of new anticancer agents, some conditions need to be fulfilled: the selected tracer should show a response that is related to the antitumoral effects, the quantitative value of this response should be interpretable to the antitumoral action, and the timing of the PET scan should be optimized to action of the drug. These conditions are not necessarily known at the start of a drug-development program and need to be explored. We proposed a translational imaging activity in which experiments in spheroids and later in xenografts are coupled to modeling of growth inhibition and to the related changes in the kinetics of PET tracers and other biomarkers. In addition, we demonstrated how this information can be used for planning clinical trials. METHODS: The first part of this concept is illustrated in a spheroid model with BT474 breast cancer cells treated with the heat shock protein 90 (Hsp90) inhibitor NVP-AUY922. The growth-inhibitory effect after a pulse treatment with the drug was measured with digital image analysis to determine effects on volume with high accuracy. The growth-inhibitory effect was described mathematically by a combined E(max) and time course model fitted to the data. The model was then used to simulate a once-per-week treatment; in these experiments the uptake of the PET tracers (18)F-FDG and 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) was determined at different doses and different time points. RESULTS: A drug exposure of 2 h followed by washout of the drug from the culture medium generated growth inhibition that was maximal at the earliest time point of 1 d and decreased exponentially with time during 10-12 d. The uptake of (18)F-FDG per viable tumor volume was minimally affected by the treatment, whereas the (18)F-FLT uptake decreased in correlation with the growth inhibition. CONCLUSION: The study suggests a prolonged action of the Hsp90 inhibitor that supports a once-per-week schedule. (18)F-FLT is a suitable tracer for the monitoring of effect, and the (18)F-FLT PET study might be performed within 3 d after dosing.  相似文献   
10.
The effect of the treatment of Angle Class II, Division 2 malocclusion was studied in 22 children by x-ray cephalometry and by recording the relation between the retruded and the intercuspal mandibular positions. The treatment was performed in three phases. In the first phase the upper incisors were proclined, and the deep bite was corrected with an upper removable plate. In the second phase the distal occlusion was corrected with an activator. The result was retained in the third phase with a second activator designed for retention. The relation between the retruded (RCP) and the intercuspal (ICP) mandibular positions was recorded with wax bites and dental casts mounted in a modified gnathothesiometer. The anteroposterior distance between RCP and ICP was large before the start of the treatment. The distance was unchanged after proclination of the upper incisors and correction of the deep bite but decreased after correction of the distal occlusion and increased again somewhat during the retention phase. The proclination of the upper incisors and the correction of the deep bite (phase one of the treatment) did not result in mandibular anterior positioning. This fact and the results of the recordings of the relation between RCP and ICP were interpreted as evidence that the mandible is not posteriorly displaced in Class II, Division 2 malocclusion.  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