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   25316篇
  免费   2368篇
  国内免费   72篇
耳鼻咽喉   261篇
儿科学   589篇
妇产科学   343篇
基础医学   3090篇
口腔科学   812篇
临床医学   3261篇
内科学   5442篇
皮肤病学   617篇
神经病学   1854篇
特种医学   1037篇
外科学   3581篇
综合类   515篇
一般理论   24篇
预防医学   2667篇
眼科学   360篇
药学   1991篇
中国医学   23篇
肿瘤学   1289篇
  2021年   365篇
  2020年   208篇
  2019年   343篇
  2018年   375篇
  2017年   273篇
  2016年   340篇
  2015年   394篇
  2014年   529篇
  2013年   833篇
  2012年   1129篇
  2011年   1123篇
  2010年   635篇
  2009年   597篇
  2008年   1041篇
  2007年   1055篇
  2006年   1104篇
  2005年   1098篇
  2004年   1026篇
  2003年   973篇
  2002年   975篇
  2001年   983篇
  2000年   1008篇
  1999年   854篇
  1998年   339篇
  1997年   283篇
  1996年   276篇
  1995年   266篇
  1994年   218篇
  1993年   227篇
  1992年   611篇
  1991年   636篇
  1990年   585篇
  1989年   524篇
  1988年   508篇
  1987年   487篇
  1986年   482篇
  1985年   487篇
  1984年   346篇
  1983年   297篇
  1982年   220篇
  1981年   208篇
  1979年   324篇
  1978年   238篇
  1977年   204篇
  1975年   168篇
  1974年   214篇
  1973年   204篇
  1972年   169篇
  1971年   192篇
  1970年   170篇
排序方式: 共有10000条查询结果,搜索用时 937 毫秒
1.
Cutaneous leiomyomas are rare benign smooth‐muscle tumors. These lesions are distinguished based on their cell of origin and are subclassified as pilar leiomyoma, angioleiomyoma, and genital‐type leiomyoma. Nipple leiomyoma is the least common genital‐type leiomyoma, arising from the dartoic muscle cell of the nipple. Histologic examination of the lesion is necessary for definitive diagnosis, and these uncommon tumors can pose a diagnostic challenge. We describe herein a series of six nipple leiomyomas with a spectrum of histologic appearances.  相似文献   
2.
3.
4.
5.
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   
6.
This study explored the relationship between active mediation, exposure to Daniel Tiger’s Neighborhood, and key indicators of preschoolers’ social and emotional development. One hundred and twenty-seven children aged 2–6 either watched or did not watch 10 episodes of Daniel Tiger’s Neighborhood over a two-week period. Results revealed that preschoolers who watched the program exhibited higher levels of empathy, self-efficacy, and emotion recognition when their regular TV-watching experiences are frequently accompanied by active mediation. This was especially true for younger preschoolers and preschoolers from low-income families. Implications for policy-makers, parents, producers of prosocial programming, and educators are discussed.  相似文献   
7.
8.
9.
Measurement of P-selectin on activated platelets as a means of measuring platelet function utilizing the technology described here has the advantage of not requiring immediate access to specialist equipment and expertise. Blood samples are activated, fixed, stored, and transported to a central laboratory for flow cytometric analysis. Here we have compared P-selectin with other more traditional approaches to measuring platelet function in blood and/or platelet-rich plasma (PRP) from patients with acute coronary syndromes on treatment for at least 1 month with either aspirin and clopidogrel or aspirin with prasugrel. The comparators were light transmission aggregometry (LTA), VerifyNow and Multiplate aggregometry (for determining the effects of aspirin) and LTA, VerifyNow and Multiplate together with the BioCytex VASP phosphorylation assay (for the P2Y12 antagonists). The P-selectin Aspirin Test revealed substantial inhibition of platelet function in all but three of 96 patients receiving aspirin with clopidogrel and in none of 51 patients receiving aspirin and prasugrel. The results were very similar to those obtained using LTA. There was only one patient with high residual platelet aggregation and low P-selectin expression. The same patients identified as “non-responders” to aspirin also presented with the highest residual platelet activity as measured using the VerifyNow system, although not quite as well separated from the other values. With the Multiplate test only one of these patients clearly stood out from the others. The results obtained using the P-selectin P2Y12 Test in 102 patients taking aspirin and clopidogrel were similar to the more traditional approaches in that a wide scatter of results was obtained. Generally, high values seen with the P-selectin P2Y12 Test were also high with the LTA, VerifyNow, Multiplate, and BioCytex VASP P2Y12 Tests. Similarly, low residual platelet function using the P2Y12 test was seen irrespective of the testing procedure used. However, there were differences in some patients. Prasugrel was always more effective than clopidogrel in inhibiting platelet function with none of 56 patients (P-selectin and VerifyNow), only 2 of 56 patients (Multiplate) and only 3 of 56 patients (Biocytex VASP) demonstrating high on-treatment residual platelet reactivity (HRPR) defined using previously published cut-off values. The exception was LTA where there were 11 of 56 patients with HRPR. It remains to be seen which experimental approach provides the most useful information regarding outcomes after adjusting therapies in treated patients.  相似文献   
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