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   20746篇
  免费   1665篇
  国内免费   45篇
耳鼻咽喉   149篇
儿科学   788篇
妇产科学   578篇
基础医学   2645篇
口腔科学   277篇
临床医学   2268篇
内科学   4122篇
皮肤病学   377篇
神经病学   2172篇
特种医学   373篇
外国民族医学   5篇
外科学   2396篇
综合类   169篇
一般理论   68篇
预防医学   2886篇
眼科学   276篇
药学   1308篇
  4篇
中国医学   55篇
肿瘤学   1540篇
  2024年   114篇
  2023年   325篇
  2022年   528篇
  2021年   1003篇
  2020年   609篇
  2019年   826篇
  2018年   940篇
  2017年   670篇
  2016年   687篇
  2015年   742篇
  2014年   976篇
  2013年   1252篇
  2012年   1754篇
  2011年   1743篇
  2010年   923篇
  2009年   740篇
  2008年   1219篇
  2007年   1297篇
  2006年   1040篇
  2005年   1001篇
  2004年   898篇
  2003年   813篇
  2002年   619篇
  2001年   149篇
  2000年   147篇
  1999年   130篇
  1998年   140篇
  1997年   97篇
  1996年   56篇
  1995年   71篇
  1994年   65篇
  1993年   50篇
  1992年   88篇
  1991年   76篇
  1990年   69篇
  1989年   75篇
  1988年   45篇
  1987年   50篇
  1986年   45篇
  1985年   40篇
  1984年   39篇
  1983年   21篇
  1982年   21篇
  1981年   25篇
  1980年   24篇
  1979年   26篇
  1977年   18篇
  1975年   20篇
  1974年   15篇
  1971年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
The potential modulation spectrum of CdS Q-dots deposited on an optically transparent electrode has been investigated. A peak at 580 nm, that corresponded to bleaching of a sub-bandgap absorption, was observed. It was established that the peak was related to electron injection into the conduction band of the CdS Q-dots. The mechanism by which the absorption of surface states may be monitored using potential-modulated absorption spectroscopy is outlined.  相似文献   
32.
Surveys were sent to Harvard School of Dental Medicine students and graduates from the classes of 2000 through 2006 to determine their current primary means of achieving mandibular anesthesia. Orthodontists and orthodontic residents were excluded. All subjects received clinical training in the conventional inferior alveolar nerve block and two alternative techniques (the Akinosi mandibular block and the Gow-Gates mandibular block) during their predoctoral dental education. This study tests the hypothesis that students and graduates who received training in the conventional inferior alveolar nerve block, the Akinosi mandibular block, and the Gow-Gates mandibular block will report more frequent current utilization of alternatives to the conventional inferior alveolar nerve block than clinicians trained in the conventional technique only. At the 95 percent confidence level, we estimated that between 3.7 percent and 16.1 percent (mean=8.5 percent) of clinicians trained in using the Gow-Gates technique use this injection technique primarily, and between 35.4 percent and 56.3 percent (mean=47.5 percent) of those trained in the Gow-Gates method never use this technique. At the same confidence level, between 0.0 percent and 3.8 percent (mean=0.0 percent) of clinicians trained in using the Akinosi technique use this injection clinical technique primarily, and between 62.2 percent and 81.1 percent (mean=72.3 percent) of those trained in the Akinosi method never use this technique. No control group that was completely untrained in the Gow-Gates or Akinosi techniques was available for comparison. However, we presume that zero percent of clinicians who have not been trained in a given technique will use the technique in clinical practice. The confidence interval for the Gow-Gates method excludes this value, while the confidence interval for the Akinosi technique includes zero percent. We conclude that, in the study population, formal clinical training in the Gow-Gates and Akinosi injection techniques lead to a small but significant increase in current primary utilization of the Gow-Gates technique. No significant increase in current primary utilization of the Akinosi technique was found.  相似文献   
33.
34.
Lay beliefs about the causes of common mental health conditions may perpetuate stigmatizing attitudes toward individuals with mental illness. Furthermore, some of these beliefs may be subject to intergroup membership bias based on gender congruence, as depression is more prevalent in women and alcohol dependence is more prevalent in men. Respondents listened to a vignette portraying an individual with depression or alcohol dependence and were asked how likely the vignette character’s (X’s) symptoms were due to the following causes: X’s bad character, genetics, stress, the way X was raised, and the normal ups and downs of life. Respondents endorsed bad character as a more likely cause of alcohol dependence compared to depression, but this was stronger for women respondents. Men, on the other hand, were more likely to endorse bad character as a cause of depression compared to women. A trend suggested that the overall tendency for alcohol to be attributed to genetics more than depression was stronger for men, whereas women endorsed genetics as a more likely cause of depression than men. Finally, men were significantly more likely to attribute characters’ symptoms to the normal ups and downs of life compared to women. Overall, these patterns suggest gender differences in attitudes about the underlying causes of alcohol dependence and depression that may be consistent with intergroup membership bias. Anti-stigma interventions aimed at reducing bias toward individuals with these common, gender-typical disorders should consider adapting strategies to target intergroup membership bias.  相似文献   
35.

Background

Cognitive dysfunction is associated with reduced postoperative weight loss up to 2 years following surgery, though the role of cognition at more extended follow-up is not yet understood. Thirty-six months following bariatric surgery, we retrospectively compared obese and non-obese patients on 12-week postoperative cognitive performance. We hypothesized that early postoperative cognitive dysfunction would predict higher body mass index (BMI) and lower percent weight loss (%WL) in the total sample at 36 month follow-up.

Materials and Methods

Fifty-five individuals undergoing bariatric surgery completed cognitive testing at preoperative baseline and serial postoperative timepoints, including 12 weeks and 36 months. Cognitive test scores were normed for demographic variables. Percent weight loss (%WL) and body mass index (BMI) were calculated at 36-month follow-up.

Results

Adjusting for gender, baseline cognitive function, and 12-week %WL, 12-week global cognitive test performance predicted 36 month postoperative %WL and BMI. Partial correlations revealed recognition memory, working memory, and generativity were most strongly related to weight loss.

Conclusion

Cognitive function shortly after bariatric surgery is closely linked to extended postoperative weight loss at 36 months. Further work is necessary to clarify mechanisms underlying the relationship between weight loss, durability, and cognitive function, including contribution of adherence, as this may ultimately help identify individuals in need of tailored interventions to optimize postoperative weight loss.  相似文献   
36.
The multiple organ dysfunction syndrome is a common but poorly understood complication of critical illness. Its evolution reflects the interactions of an acute, life-threatening insult, the response of the host to that insult, and the therapeutic measures instituted to restore normal homeostasis. Although the cellular mechanisms remain elusive, processes such as inflammation, microvascular thrombosis, apoptosis, and fibrosis and tissue repair contribute to its clinical expression. In the lung, these forces create the characteristic changes of ARDS; that common disorder, however, is better seen as one manifestation of a systemic process than as an isolated problem of the lung. Therapy, in the absence of a more sophisticated understanding of pathologic mechanism, is supportive. The growing recognition that iatrogenic factors contribute to the expression of MODS has highlighted the need for the clinician to be aware of the potential for harm inherent with every intervention.  相似文献   
37.
38.
Social Psychiatry and Psychiatric Epidemiology - Persecutory delusions are one of the key problems seen in psychotic conditions. The aim of the study was to assess for the first time the levels of...  相似文献   
39.
We studied healthy, first-degree relatives of patients with schizophrenia to test the hypothesis that deficits in cognitive skill learning are associated with genetic liability to schizophrenia. Using the Weather Prediction Task (WPT), 23 healthy controls and 10 adult first-degree Relatives Of Schizophrenia (ROS) patients were examined to determine the extent to which cognitive skill learning was automated using a dual-task paradigm to detect subtle impairments in skill learning. Automatization of a skill is the ability to execute a task without the demand for executive control and effortful behavior and is a skill in which schizophrenia patients possess a deficit. ROS patients did not differ from healthy controls in accuracy or reaction time on the WPT either during early or late training on the single-task trials. In contrast, the healthy control and ROS groups were differentially affected during the dual-task trials. Our results demonstrate that the ROS group did not automate the task as well as controls and continued to rely on controlled processing even after extensive practice. This suggests that adult ROS patients may engage in compensatory strategies to achieve normal levels of performance and support the hypothesis that impaired cognitive skill learning is associated with genetic risk for schizophrenia.  相似文献   
40.
We evaluated management of positive sub‐areolar/nipple duct margins in nipple‐sparing mastectomies (NSM) at our institution. Retrospective chart review of all NSM from January 2007 to April 2012 was performed and patient, tumor, and treatment information was collected. Sub‐areolar/nipple duct margins included ductal tissue from within the nipple. Of 438 NSM, 22 (5%) had positive sub‐areolar/nipple duct margins; 21 of 220 cancer‐bearing breasts (10%) and 1 of 218 prophylactic mastectomies (0.5%). Positive margins included four with invasive lobular carcinoma and 18 with ductal carcinoma in situ (DCIS). Management included removal of eight nipples and nine nipple areola complexes (NAC). Four of 17 nipple/NAC specimens had evidence of residual DCIS and none had residual invasive cancer. The majority of nipple/NAC specimens excised for a positive margin had no residual malignancy. Future studies are needed to determine the extent of NAC tissue removal required for positive margins.  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