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   898209篇
  免费   63535篇
  国内免费   2322篇
耳鼻咽喉   12475篇
儿科学   28671篇
妇产科学   26149篇
基础医学   126561篇
口腔科学   24690篇
临床医学   74702篇
内科学   183011篇
皮肤病学   18982篇
神经病学   71344篇
特种医学   36447篇
外国民族医学   336篇
外科学   142145篇
综合类   19021篇
一般理论   247篇
预防医学   64506篇
眼科学   20077篇
药学   63811篇
中国医学   1798篇
肿瘤学   49093篇
  2018年   9056篇
  2017年   7164篇
  2016年   7673篇
  2015年   8726篇
  2014年   12374篇
  2013年   19209篇
  2012年   25669篇
  2011年   27276篇
  2010年   16578篇
  2009年   15786篇
  2008年   26135篇
  2007年   27742篇
  2006年   27918篇
  2005年   27452篇
  2004年   26296篇
  2003年   25466篇
  2002年   25056篇
  2001年   41361篇
  2000年   42557篇
  1999年   36267篇
  1998年   9966篇
  1997年   9148篇
  1996年   9083篇
  1995年   8447篇
  1994年   8086篇
  1993年   7588篇
  1992年   28205篇
  1991年   26989篇
  1990年   26414篇
  1989年   25350篇
  1988年   23560篇
  1987年   23182篇
  1986年   22257篇
  1985年   21159篇
  1984年   15816篇
  1983年   13485篇
  1982年   8088篇
  1979年   14592篇
  1978年   10209篇
  1977年   8627篇
  1976年   8149篇
  1975年   8959篇
  1974年   10698篇
  1973年   10184篇
  1972年   9661篇
  1971年   8919篇
  1970年   8584篇
  1969年   8026篇
  1968年   7685篇
  1967年   7087篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
Introduction: This study investigated variables associated with subjective decline in executive function among Veterans of Operations Enduring Freedom, Iraqi Freedom, and New Dawn (OEF/OIF/OND) following a history of blast-related mild traumatic brain injury (mTBI).

Method: Fifty-six male U.S. Veterans (MAge = 35.3 ± 8.8 years) with a history of blast-related mTBI (6.6 ± 3.2 years post injury) completed a battery of self-report questionnaires and neuropsychological measures. Participants rated current and retrospectively estimated pre-mTBI executive function difficulties on the Frontal Systems Behavior Scale (FrSBe). A difference score (post- minus pre-mTBI ratings) was the dependent variable (?FrSBe). Linear regression models examined variables predicting ?FrSBe, including: pre-injury characteristics (education, premorbid intelligence), injury-related characteristics (number of blast exposures, losses of consciousness), post-injury clinical symptoms (PTSD Checklist–Military version; Pittsburgh Sleep Quality Index), and post-injury neuropsychological performances on executive function measures (Trail Making Test Part B; Controlled Oral Word Association Test; Auditory Consonant Trigrams; Wisconsin Card Sorting Test).

Results: While 11% of participants had a clinically elevated pre-injury FrSBe total score, 82% had a clinically elevated post-injury FrSBe total score. Only self-reported PTSD symptom severity independently predicted perceived change in executive function.

Conclusions: Many OEF/OIF/OND Veterans with a history of blast-related mTBI experience subjective decline in executive function following injury. Perceived executive function decline was associated with higher PTSD symptom severity, aligning with previous research associating PTSD with cognitive complaints. Results did not support a correspondence between perceived cognitive change and neuropsychological performances.  相似文献   
143.
AIM: To establish the association between lymph node involvement and the response to neoadjuvant therapy in locally advanced rectal cancer.METHODS: Data of 130 patients with mid and low locally advanced rectal adenocarcinoma treated with neoadjuvant chemoradiation followed by radical surgery over a 5-year period were reviewed. Tumor staging was done by endorectal ultrasound and/or magnetic resonance imaging. Tumor response to neoadjuvant therapy was determined by T-downstaging and tumor regression grading (TRG). Pathologic complete response (pCR) is defined as the absence of tumor cells in the surgical specimen (ypT0N0). The varying degrees TRG were classified according to Mandard’s scoring system. The evaluation of the response is based on the comparison between previous clinico-radiological staging and the results of pathological evaluation. χ2 and Spearman’s correlation tests were used for the comparison of variables.RESULTS: Pathologic complete response (pCR, ypT0N0, TRG1) was observed in 19 cases (14.6%), and other 18 (13.8%) had only very few residual malignant cells in the rectal wall (TRG2). T-downstaging was found in 63 (48.5%). Mean lymph node retrieval was 9.4 (range 0-38). In 37 cases (28.5%) more than 12 nodes were identified in the surgical specimen. Preoperative lymph node involvement was seen in 77 patients (59.2%), 71 N1 and 6 N2. Postoperative lymph node involvement was observed in 41 patients (31.5%), 29 N1 and 12 N2, while the remaining 89 were N0 (68.5%). In relation to ypT stage, we found nodal involvement of 9.4% in ypT0-1, 22.2% in ypT2 and 43.7% in ypT3-4. Of the 37 patients considered “responders” to neoadjuvant therapy (TRG1 and 2), there were only 4 N+ (10.8%) and the remainder N0 (89.2%). In the “non responders” group (TRG 3, 4 and 5), 37 cases were N+ (39.8%) and 56 (60.2%) were N0 (P < 0.001).CONCLUSION: Response to neoadjuvant chemoradiation in rectal cancer is associated with lymph node involvement.  相似文献   
144.
145.
146.
147.
148.
149.
150.
The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.  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