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   35303篇
  免费   2359篇
  国内免费   369篇
耳鼻咽喉   457篇
儿科学   764篇
妇产科学   842篇
基础医学   4463篇
口腔科学   1214篇
临床医学   3340篇
内科学   6625篇
皮肤病学   364篇
神经病学   3923篇
特种医学   1230篇
外国民族医学   1篇
外科学   4548篇
综合类   1145篇
一般理论   15篇
预防医学   2960篇
眼科学   1138篇
药学   2739篇
  4篇
中国医学   226篇
肿瘤学   2033篇
  2023年   199篇
  2022年   360篇
  2021年   664篇
  2020年   424篇
  2019年   556篇
  2018年   702篇
  2017年   617篇
  2016年   602篇
  2015年   773篇
  2014年   985篇
  2013年   1461篇
  2012年   1981篇
  2011年   2213篇
  2010年   1343篇
  2009年   1170篇
  2008年   1966篇
  2007年   2147篇
  2006年   2056篇
  2005年   2034篇
  2004年   1971篇
  2003年   1855篇
  2002年   1825篇
  2001年   710篇
  2000年   653篇
  1999年   648篇
  1998年   466篇
  1997年   426篇
  1996年   340篇
  1995年   353篇
  1994年   287篇
  1993年   301篇
  1992年   399篇
  1991年   370篇
  1990年   342篇
  1989年   336篇
  1988年   308篇
  1987年   289篇
  1986年   285篇
  1985年   301篇
  1984年   246篇
  1983年   245篇
  1982年   244篇
  1981年   241篇
  1980年   221篇
  1979年   188篇
  1978年   180篇
  1977年   190篇
  1976年   149篇
  1975年   159篇
  1974年   115篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates.  相似文献   
2.
3.
ABSTRACT

Forensic DNA analysis is dependent on comparing the known and the unknown. Expand the number of known profiles, and the likelihood of a successful match increases. Forensic use of DNA is moving towards comparing samples of unknown origin with publicly available genetic data, such as the records held by genetic genealogy providers. Use of forensic genetic genealogy has yielded a number of recent high-profile successes but has raised ethical and privacy concerns. Navigating family trees is complex, even more so when combined with a comparison of genetic relationships. This intelligence-gathering process has led to occasional false leads, and its use also risks a public backlash, similar to concerns over Cambridge Analytica. A cautious approach to use of this technique is therefore warranted.  相似文献   
4.
5.
The clinical outcome and appropriate management for patients showing 'borderline changes' on allograft biopsy after renal transplantation is still controversial. In an attempt to identify predictive factors of clinical outcome of patients with such lesions, we reviewed the clinical course of 91 patients with borderline changes. Multivariate analysis revealed significant and independent effects of histological stage (i + t < or = or > 2) and time to borderline changes (< or = or > 3 months after transplant) on serum creatinine levels at 1 year from borderline changes episodes (respectively, p = 0.04 and p = 0.02) and only a significant effect of time to borderline changes on serum creatinine levels at 2 years (p = 0.005). Renal function at 1 year and 2 years as 5- and 8-year graft survival were not significantly different in the group of patients treated with antirejection therapy (T group, n = 49) compared with the untreated group (UT group, n = 42). This study strongly suggests that borderline changes with histological score (i + t) > 2 and late episodes of borderline changes should be considered to be of poor prognosis.  相似文献   
6.
7.
Using complete denture treatment as an introduction to clinical patient care for dental students, the purposes of the Complete Denture Prosthodontics Transition Clinic at the University of Colorado School of Dentistry are to reduce the time lapse between the preclinical complete denture prosthodontics course and the first denture patient experience, and to encourage development of student self-confidence and skills. In the 2002 spring semester, faculty at the University of Colorado School of Dentistry initiated the Complete Denture Prosthodontics Transition Clinic for DS-II (second-year) dental students, as an introduction to clinical patient care. Each patient was assigned to a team of two dental students. Three Division of Prosthodontics faculty members staffed each clinic session, providing a student-to-faculty ratio of approximately 6.6:1 and a patient-to-faculty ratio of approximately 3.3:1. All DS-II students in the Class of 2004 delivered their first complete dentures no later than 8 months (average, 184 days) after the last day of the preclinical complete denture prosthodontics course. The time from the diagnostic appointment through the denture placement appointment averaged 39 days for patients treated in this program, compared with an average of 98 days or more for previous classes. The program was successful in achieving the goal of reducing the time lapse between the preclinical complete denture prosthodontics course and the first denture patient experience.  相似文献   
8.
Over 100 mutations in the presenilin‐1 gene (PSEN1) have been shown to result in familial early onset Alzheimer disease (EOAD), but only a relatively few give rise to plaques with an appearance like cotton wool (CWP) and/or spastic paraparesis (SP). A family with EOAD, seizures and CWP was investigated by neuropathological study and DNA sequencing of the PSEN1 gene. Aβ was identified in leptomeningeal vessels and in cerebral plaques. A single point mutation, p.L420R (g.1508T > G) that gives rise to a missense mutation in the eighth transmembrane (TM8) domain of PS1 was identified in two affected members of the family. p.L420R (g.1508T > G) is the mutation responsible for EOAD, seizures and CWP without SP in this family.  相似文献   
9.
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