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   30728篇
  免费   2255篇
  国内免费   59篇
耳鼻咽喉   159篇
儿科学   1245篇
妇产科学   998篇
基础医学   3658篇
口腔科学   357篇
临床医学   4841篇
内科学   5831篇
皮肤病学   518篇
神经病学   2943篇
特种医学   495篇
外科学   2558篇
综合类   389篇
一般理论   39篇
预防医学   4441篇
眼科学   491篇
药学   1905篇
中国医学   43篇
肿瘤学   2131篇
  2023年   254篇
  2022年   320篇
  2021年   589篇
  2020年   465篇
  2019年   761篇
  2018年   822篇
  2017年   663篇
  2016年   717篇
  2015年   799篇
  2014年   1057篇
  2013年   1613篇
  2012年   2389篇
  2011年   2342篇
  2010年   1305篇
  2009年   1195篇
  2008年   1987篇
  2007年   2128篇
  2006年   2012篇
  2005年   2052篇
  2004年   1930篇
  2003年   1769篇
  2002年   1665篇
  2001年   274篇
  2000年   213篇
  1999年   244篇
  1998年   332篇
  1997年   260篇
  1996年   212篇
  1995年   232篇
  1994年   199篇
  1993年   176篇
  1992年   136篇
  1991年   114篇
  1990年   140篇
  1989年   118篇
  1988年   88篇
  1987年   86篇
  1986年   89篇
  1985年   101篇
  1984年   113篇
  1983年   88篇
  1982年   112篇
  1981年   87篇
  1980年   86篇
  1979年   65篇
  1978年   70篇
  1977年   50篇
  1975年   43篇
  1973年   41篇
  1972年   39篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
PURPOSE: To explore potential indicators of the quality of end-of-life services for cancer patients that could be monitored using existing administrative data. METHODS: Quality indicators were identified and assessed by literature review for proposed indicators, focus groups with cancer patients and family members to assess candidate indicators and generate new ideas, and an expert panel ranking the meaningfulness and importance of each potential indicator using a modified Delphi approach. RESULTS: There were three major concepts of poor quality of end-of-life cancer care that could be examined using currently-available administrative data (such as Medicare claims): institution of new anticancer therapies or continuation of ongoing treatments very near death; a high number of emergency room visits, inpatient hospital admissions, or intensive care unit days near the end of life; and a high proportion of patients never enrolled in hospice, only admitted in the last few days of life, or dying in an acute-care setting. Concepts such as access to psychosocial and other multidisciplinary services and pain and symptom control are important and may eventually be feasible, but they cannot currently be applied in most data systems. Indicators based on limiting the use of treatments with low probability of benefit or indicators based on economic efficiency were not acceptable to patients, family members, or physicians. CONCLUSION: Several promising claims-based quality indicators were identified that, if found to be valid and reliable within data systems, could be useful in identifying health-care systems in need of improving end-of-life services.  相似文献   
52.
Although anxiety is a well-established obstacle to the delivery of effective health care, there have been no attempts to measure it in the optometric consulting room. In this paper, we introduce physiological and psychological techniques that may be used to evaluate anxiety and arousal in the consulting room and present data from a small group of patients attending for a routine eye examination. Specifically, arousal was assessed before, during, and after the examination by measuring skin conductance in five patients. Anxiety was evaluated using the State-Trait Anxiety Inventory. Our data confirm the ability of these techniques to quantify arousal and anxiety in the optometric consulting room and reveal a previously unknown but important facet of the eye examination. We conclude that these techniques are suitable for use in further experimental work and may be used to identify factors capable of reducing anxiety in the optometric consulting room.  相似文献   
53.
OBJECTIVES: To critically review and integrate, from a developmental perspective, recent magnetic resonance imaging (MRI) studies of 4 childhood psychiatric disorders: schizophrenia, bipolar disorder (BD), attention-deficit hyperactivity disorder (ADHD), and major depressive disorder (MDD). METHOD: We reviewed published reports in refereed journals. We briefly describe the major findings with respect to the brain morphometry, chemistry, and function of children with psychiatric disorders and synthesize the reports in a summary to update clinicians. RESULTS: Some cortical grey matter abnormalities associated with schizophrenia appear to predate the onset of frank psychosis and continue to advance after the onset of psychosis, at least in more severe cases. Pediatric BD is associated with abnormalities in a circuit, thought to be involved in mood regulation, that encompasses the amygdala, striatum, and ventral PFC. Frontostriatal abnormalities are reported consistently in ADHD, potentially reflecting abnormalities in the development of cognitive control. Children with MDD show prefrontal cortical alterations that may differ in familial and nonfamilial subtypes of MDD. CONCLUSIONS: Results from neuroimaging studies of childhood psychopathology reveal abnormalities in the developmental trajectories observed in healthy children. Although MRI has increased our understanding of the pathophysiology of these disorders, routine neuroimaging for children with severe emotional disturbances is not indicated for diagnostic purposes.  相似文献   
54.
55.
56.
57.
58.
59.
Patient on-off diaries are used in clinical trials, but a method to assure agreement between patient and examiner has never been developed. We tested whether a patient-teaching tape increased the rate of agreement between patient diary ratings and simultaneous neurologic assessment by a trained professional. A total of 32 consecutive patients who had Parkinson's disease with motor fluctuations independently completed a 4-h on-off diary (nine ratings) at the same time as an examiner. Those with <80% agreement with the examiner (n = 20) were randomized to view either a training tape that showed motor fluctuations (experimental group) or another videotape of general patient educational material (control group). All patients then underwent the same 4-h assessment of motor fluctuations. To test for long-term retention, they returned 1 month later and, without reviewing the videotape, underwent a final 4-h correlation assessment. After the training tape, the experimental group showed significant improvement, whereas the control group showed no improvement. Furthermore, another month later, the improvement in the experimental group was retained. Based on these findings, we suggest that future clinical trials assessing motor fluctuations incorporate this tape into their basic methodology.  相似文献   
60.
We investigated the role of metabolism in muscle fatigue during voluntary exercise in persons with mild multiple sclerosis (MS). Six MS and 8 healthy control subjects performed intermittent, progressive, isometric contractions of the ankle dorsiflexors, during which we measured maximum voluntary force (MVC), inorganic phosphate (Pi), phosphocreatine (PCr), and pH. During exercise. MVC fell sooner in MS, but by the end of exercise the relative decrease in MVC was similar in both groups. In contrast, at the end of exercise Pi/PCr increased to 1.86 ± 0.22 in controls but to only 0.66 ± 0.04 in MS (P < 0.01); likewise, pH was 6.75±0.04 in controls and unchanged (7.06 ± 0.04) in MS (P <0.01). The smaller metabolic change at the same relative exercise intensity suggests a failure of muscle activation that is present even in mild MS. Neurophsyiologic measures of activation indicated some central activation failure and no neuromuscular junction impairment in MS, and suggested that activation failure beyond the muscle membrane(excitation–contraction coupling) may be important in MS. We conclude that metabolic factors do not play a significant role in the development of muscle fatigue during voluntary exercise in mild MS. © 1994 John Wiley & Sons, Inc.  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