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   440篇
  免费   50篇
儿科学   14篇
妇产科学   6篇
基础医学   73篇
口腔科学   1篇
临床医学   40篇
内科学   63篇
皮肤病学   7篇
神经病学   21篇
特种医学   16篇
外科学   43篇
综合类   13篇
预防医学   92篇
药学   26篇
肿瘤学   75篇
  2022年   3篇
  2021年   9篇
  2020年   9篇
  2019年   10篇
  2018年   12篇
  2017年   2篇
  2016年   9篇
  2015年   14篇
  2014年   18篇
  2013年   10篇
  2012年   21篇
  2011年   27篇
  2010年   14篇
  2009年   9篇
  2008年   19篇
  2007年   24篇
  2006年   21篇
  2005年   23篇
  2004年   10篇
  2003年   16篇
  2002年   24篇
  2001年   18篇
  2000年   18篇
  1999年   17篇
  1998年   2篇
  1997年   3篇
  1996年   3篇
  1995年   6篇
  1994年   2篇
  1993年   7篇
  1992年   15篇
  1991年   14篇
  1990年   8篇
  1989年   16篇
  1988年   11篇
  1987年   8篇
  1986年   9篇
  1985年   2篇
  1984年   2篇
  1982年   5篇
  1978年   3篇
  1976年   1篇
  1975年   1篇
  1974年   2篇
  1973年   2篇
  1972年   2篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1959年   1篇
排序方式: 共有490条查询结果,搜索用时 15 毫秒
1.
2.
Summary This study was designed to verify if the decrease in blood prolactin (PRL) induced by selective face cooling during exercise could be part of a response to specific body thermal stress. Five healthy trained male cyclists presenting a significant plasma PRL elevation to exercise were, on three occasions and at weekly interval, submitted to a submaximal exercise (approx. 65% ) on ergocycle with and without selective face cooling. In absence of face cooling a first trial served to establish reference values for workload, heart rate and plasma PRL levels, the latter increasing markedly (450% of resting values) in these conditions. On a second trial but with workload maintained at reference values (222±9 W), a significant bradycardia was observed with face cooling; furthermore, plasma PRL response to exercise was significantly reduced (to 31% of original response). On a third trial with face cooling, workload had to be significantly augmented (242±10 W) to maintain heart rate at reference level (78%HR max); in addition, plasma PRL response to exercise was almost unchanged compared to the reference-value level. The absence of a significant face cooling-induced decrease in sympathetic tonus, as evaluated through peripheral plasma catecholamines response, does not indicate a role for the autonomic nervous system in the face cooling-induced reduction of both heart rate and PRL responses during exercise. Assay of circulating peripheral beta-endorphins could indicate that the face cooling-induced PRL blunted response does not necessarily involve an opioid mediation. It was concluded that decreased plasma PRL levels could be associated to bradycardia, hyposudation and peripheral vaso-constriction to constitute an integrated response to face cooling during thermal stress. This study was supported by grants from Natural Sciences and Engineering Research Council of Canada and from Régie de la Sécurité dans les Sports du Québec  相似文献   
3.
The aim of this study was to compare the survival of 116 patients with breast cancer initially treated at the First Teaching Hospital (FTH) of Norman Bethune University of Medical Sciences located in Changchun, China, from 1986 to 1991 with the survival of 886 patients seen in the “Hipital du Saint-Sacrement” (HSS) located in Quebec City, Canada, from 1987 to 1992. The clinical data were collected from the hospital records at FTH. The vital status for Chinese patients was obtained from letters of follow-up or the records of local police offices. The list of patients treated at HSS and the data for each woman were extracted from computerized data banks. The major variables studied included age at diagnosis, tumor size at pathology (cm), number of lymph nodes involved, breast surgery and adjuvant treatments of breast cancer (chemotherapy, radiotherapy, immuno-therapy). Age at diagnosis was substantially lower among patients with breast cancer seen at FTH compared to those treated at HSS (x) 1 2 =60.95,P<0.0001). The average age at diagnosis for Chinese women was about 10 years less than that for Canadian women. Patients in the two hospitals differed with respect to tumor size at pathology (x 2 2 =6.67,P=0.036). The proportion of patients with tumor size larger than 2.0 cm was larger at FTH (48.3%) than at HSS (41.1%). The mean tumor size at pathology was 3.0 cm (standard deviation =2.1 cm) for patients treated at FTH, but 2.6 cm (standard deviation=1.8 cm) for women treated at HSS (P=0.07). The proportion of women with lymph node involvement was greater at FTH (61.1 % than that at HSS (37.3%) (x 1 2 =16.51,P<0.0001). Surgical treatment of breast cancer varied considerably. In Changchun, radical mastectomy was frequent for any stage of breast cancer patients, but partial mastectomy was never performed. The situation was reversed in Quebec. The five year observed survival was 74.2% (standard error, 0.05) among breast cancer patients seen at FTH compared to 76.0% (standard error, 0.02) among women treated at HSS. After adjustments of confounding factors, there were no significant difference in five year observed survival between the patients treated at the two hospitals (P=0.42).  相似文献   
4.
PURPOSE: The impact of consensus recommendations for systemic therapy on outcome of disease is unclear. We evaluated if compliance with guidelines for systemic adjuvant treatment is associated with improved survival of women with node-negative breast cancer. PATIENTS AND METHODS: The study population included women diagnosed with invasive node-negative breast cancer in Québec, Canada, in 1988 to 1989, 1991 to 1992, and 1993 to 1994. Information was collected by chart review, linkage with administrative databases, and queries to attending physicians. Guidelines from the 1992 St Gallen conference were used as standard of care. Survival was estimated by Kaplan-Meier and Cox proportional hazards analyses. RESULTS: Among 1,541 women, 358 died before December 1999. Median follow-up was 6.8 years. Seven-year event-free and overall survivals were 66% and 81%, respectively. Survival was 88%, 84%, and 74% in women at minimal, moderate, or high risk of recurrence. Virtually all women at minimal risk were treated according to the consensus (98.4% of 370). In comparison, adjusted hazard ratios of death were 1.0 (95% CI, 0.6 to 1.7) and 2.3 (95% CI, 1.3 to 4.0) among women at moderate risk treated according to the consensus or not, respectively. Among women at high risk, adjusted hazard ratios of death were 2.0 (95% CI, 1.4 to 2.8) and 2.7 (95% CI, 1.9 to 3.9), respectively. Both risk category (P <.0005) and compliance with guidelines (P <.0005) were independent significant predictors of survival. CONCLUSION: Treatment according to consensus recommendations is associated with improved survival of women with breast cancer in the community. Promoting the adoption of guidelines for treatment is an effective strategy for disease control.  相似文献   
5.
Mammographic breast densities are one of the strongest breast cancer risk factors. The two most frequently used classifications of breast densities are Wolfe's parenchymal pattern and the percentage of the breast with densities. In this analysis, associations of these two classifications with breast cancer risk were compared, and the dose response curve of risk with densities was examined. Three case-control studies were combined totaling 1060 cases with newly diagnosed breast cancer and 2352 controls. A single observer had assessed parenchymal pattern and percent density without any information on subjects. Relative risks (RRs) were estimated with logistic regression and spline functions adjusting for age and body weight. The two classifications were strongly correlated (r = 0.81, P = 0.0001). Breast cancer risk increased progressively with percent density reaching a 5-6-fold increase for women with 85% or more of the breast with densities compared with women with no density. In contrast, women with P2 or DY patterns had only a 2-3-fold increase in risk compared with women with N1 pattern. More importantly, among women with P2 or DY, RR varied substantially with percent density, whereas, among women with a given percent density, RR varied little with parenchymal pattern. Comparisons of multivariate models reveal that in the presence of parenchymal pattern, inclusion of percent density in the model improved the prediction of breast cancer risk (chi(2) = 35.5, P = 0.0082) but not the opposite (chi(2) = 1.1, P = 0.7662). These findings show that the percentage of the breast with densities provide more information on breast cancer risk than Wolfe's parenchymal patterns and that, once percent breast density is taken into account, no more information on breast cancer risk is given by assessing parenchymal pattern.  相似文献   
6.
BACKGROUND: The goal of this study was to assess variations with age in the management of breast carcinoma and to identify determinants of care received. METHODS: A stratified random sample was selected among women age > or = 50 newly diagnosed with lymph node negative breast carcinoma in Quebec in 1988, 1991, and 1993. Information was abstracted from medical charts. Predictors of definitive locoregional treatment (total mastectomy with lymph node dissection or breast-conserving surgery with both axillary lymph node dissection and radiation therapy) were identified by multiple logistic regression analysis. RESULTS: Overall, 1174 patients age > or = 50 years with breast carcinoma were included. Women age > or = 70 years were much less likely to receive definitive locoregional treatment compared with women ages 50-69 years (48.7% vs. 83.5%; P < 0.0001). Older women were less likely to undergo surgery with breast preservation (76.7% vs. 86.3%; P < 0.0001), radiation therapy (54.7% vs. 90.5%; P < 0.0001), dissection of the axillary lymph nodes (55.6% vs. 86.3%; P < 0.0001), or chemotherapy (1.2% vs. 13.9%; P < 0.0001), but not treatment with tamoxifen (66.4% vs. 64.7%; P = 0.41). Adjusting for comorbidity and other characteristics related to the disease, the hospital, and the attending physician, age remained a strong determinant of the probability of receiving definitive locoregional treatment (odds ratio [OR], 0.14; 95% confidence interval [95% CI], 0.12-0.18 for women age > or = 70 years vs. women ages 50-69 years). The same association was observed when women who did not undergo lymph node dissection but who received systemic adjuvant treatment were considered to have received definitive therapy (OR, 0.13; 95% CI, 0.10-0.17) for women age > or = 70 years vs. women ages 50-69 years). CONCLUSIONS: Less aggressive patterns of care are provided to elderly breast carcinoma patients, independent of comorbidity. This could explain, at least in part, the sustained breast carcinoma mortality in this population.  相似文献   
7.
8.
9.
G. Brand  R. Brisson 《Laterality》2013,18(5):583-596
The study of olfactory lateralisation in humans has given rise to many publications, but few studies have been focused on possible differences in relation to the experience towards specific odorants. The aim of the present study was to compare unilateral detection thresholds for three wines between expert and novice judges. Additionally, irritation and hedonic valence were also evaluated using monorhinal stimulations. Results showed that the novices had lower detection thresholds with the left nostril—whatever the wine—compared to the experts. Concerning hedonic rating, no nostril difference existed in the expert group contrary to the novice group, which evaluated wines as more pleasant with the left than with the right nostril. Irritation rating appeared not to be lateralised in both groups. However, the novices rated the three wines as more irritant than the experts with the right as well as with the left nostril. These findings suggest that the level of experience induced specific differences in terms of lateralisation between wine experts and novices.  相似文献   
10.
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