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   1277917篇
  免费   100082篇
  国内免费   1986篇
耳鼻咽喉   18424篇
儿科学   44377篇
妇产科学   35084篇
基础医学   182381篇
口腔科学   33706篇
临床医学   111358篇
内科学   258402篇
皮肤病学   28037篇
神经病学   100537篇
特种医学   51296篇
外国民族医学   660篇
外科学   196586篇
综合类   27076篇
现状与发展   1篇
一般理论   377篇
预防医学   95814篇
眼科学   27908篇
药学   94847篇
  2篇
中国医学   2458篇
肿瘤学   70654篇
  2018年   13162篇
  2017年   9989篇
  2016年   10916篇
  2015年   12406篇
  2014年   17205篇
  2013年   26270篇
  2012年   36123篇
  2011年   38163篇
  2010年   22861篇
  2009年   21880篇
  2008年   36737篇
  2007年   39339篇
  2006年   39585篇
  2005年   38527篇
  2004年   37664篇
  2003年   36528篇
  2002年   35866篇
  2001年   64057篇
  2000年   66557篇
  1999年   56463篇
  1998年   15147篇
  1997年   13766篇
  1996年   14208篇
  1995年   13469篇
  1994年   12787篇
  1993年   11803篇
  1992年   44596篇
  1991年   43522篇
  1990年   42264篇
  1989年   40155篇
  1988年   36925篇
  1987年   36266篇
  1986年   33645篇
  1985年   32317篇
  1984年   24164篇
  1983年   20292篇
  1982年   11737篇
  1981年   10708篇
  1980年   9537篇
  1979年   21368篇
  1978年   14839篇
  1977年   12548篇
  1976年   11708篇
  1975年   12637篇
  1974年   14680篇
  1973年   14121篇
  1972年   12957篇
  1971年   11743篇
  1970年   11062篇
  1969年   10032篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
991.
A rehabilitation program including foot sensory stimulation, balance and gait training with limited vision was performed in 24 patients with clinically defined sensory ataxia. There were 15 patients with bilateral somatosensory loss related to chronic neuropathy and nine patients with unilateral loss-related to multiple sclerosis. After training, balance control assessed using the Berg Balance Test improved similarly in both groups, and Romberg's sign disappeared in some patients, suggesting an improvement in dynamic balance and in the proprioceptive contribution. Conversely, balance assessed on a static force platform remained similar in the open-eyes condition and improved in the closed-eyes condition only in patients with unilateral sensory loss. These results show that ataxic patients can improve their balance with better results in dynamic conditions and that the relative contribution of proprioceptive and visual inputs may depend on the extent of somatosensory loss.  相似文献   
992.
Aim:   In the last three decades, the segment of population aged 60 years and older has more than doubled in Brazil. People aged 80 years and older are expected to be the fastest-growing segment in the near future. This aim of this study was to analyze the legal structures currently in place in Brazil and to provide a framework for care policies and practices towards older-adults.
Methods:   This article focuses on past and present major socioeconomic burdens on this segment of the Brazilian population as well as on public achievements to overcome inequities.
Results:   Both the public health and the social security systems have been directed to provide preferential assistance to the aged. Nonetheless, the elderly remain the most impoverished segment of Brazil and carry the burden of an overall lack of specialized services. Moreover, socioeconomic inequalities and population diversity in Brazil affects elderly care, adding complexity to this unique scenario.
Conclusion:   Brazil has adopted legal hallmarks that substantially shifted public practices towards the elderly segment from a philanthropic status to a legitimate right for care and assistance. The demographic transition that took place provides an opportunity for innovative solutions in public policies for older adults in a developing economic environment.  相似文献   
993.
994.
995.
996.
997.
We provide further evidence for the two-factor structure of the 9-item Academic Expectations Stress Inventory (AESI) using confirmatory factor analysis on a sample of 289 Canadian adolescents and 310 Singaporean adolescents. Examination of measurement invariance tests the assumption that the model underlying a set of scores is directly comparable across groups. This study also examined the cross-cultural validity of the AESI using multigroup confirmatory factor analysis across both the Canadian and Singaporean adolescent samples. The results suggested cross-cultural invariance of form, factor loadings, and factor variances and covariances of the AESI across both samples. Evidence of AESI's convergent and discriminant validity was also reported. Findings from t-tests revealed that Singaporean adolescents reported a significantly higher level of academic stress arising from self expectations, other expectations, and overall academic stress, compared to Canadian adolescents. Also, a larger cross-cultural effect was associated with academic stress arising from other expectations compared with academic stress arising from self expectations.  相似文献   
998.
999.
Background: In elderly patients, opioids may cause prominent postoperative sedation and respiratory depression. We evaluated the influence of age on the effects of opioids and plasma concentrations of fentanyl and oxycodone in cardiac surgery patients.
Methods: Thirty (≥75 years, gender M9/F21) and 20 (≤60 years, gender M20/F0) patients scheduled to undergo cardiac surgery. A standard anesthesia with fentanyl as an opioid was used. Fentanyl plasma concentrations were measured at the end of surgery and 2 h later. After tracheal extubation, when the pain intensity was at least moderate, blood samples for fentanyl and oxycodone plasma concentration measurements were taken. Thereafter, oxycodone hydrochloride 0.05 mg/kg i.v. was administered. After 15 and 45 min, pain intensity, sedation and oxycodone plasma concentration were determined. This test protocol was repeated twice.
Results: The elderly had a higher plasma concentration of fentanyl at the end of surgery than younger patients (5.7±2.2 vs. 3.8±1.2 ng/ml, P =0.001). The plasma concentrations of oxycodone were comparable between the groups. The interval between the second and the third oxycodone dose was longer in the elderly patients ( P =0.036). Pain intensity on the verbal rating scale was lower at the 45-min assessment point after all three oxycodone test doses ( P =0.008) and sedation scores were significantly higher after the third dose in the elderly patients ( P =0.035).
Conclusions: In elderly patients, the plasma concentration of fentanyl was higher but plasma levels of oxycodone were at a similar level compared with middle-aged patients. However, the elderly patients had less pain and were more sedated after doses of oxycodone.  相似文献   
1000.
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