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   136677篇
  免费   8464篇
  国内免费   2964篇
耳鼻咽喉   1779篇
儿科学   3159篇
妇产科学   4305篇
基础医学   20270篇
口腔科学   3927篇
临床医学   11646篇
内科学   24293篇
皮肤病学   2559篇
神经病学   8937篇
特种医学   4560篇
外国民族医学   19篇
外科学   18606篇
综合类   8510篇
现状与发展   5篇
一般理论   38篇
预防医学   9863篇
眼科学   3239篇
药学   12102篇
  4篇
中国医学   1721篇
肿瘤学   8563篇
  2022年   1207篇
  2021年   1846篇
  2020年   1270篇
  2019年   1639篇
  2018年   2239篇
  2017年   1769篇
  2016年   1769篇
  2015年   2286篇
  2014年   2895篇
  2013年   3263篇
  2012年   4796篇
  2011年   5316篇
  2010年   3239篇
  2009年   2762篇
  2008年   4266篇
  2007年   4592篇
  2006年   4533篇
  2005年   4088篇
  2004年   3625篇
  2003年   3373篇
  2002年   3174篇
  2001年   7190篇
  2000年   7326篇
  1999年   6099篇
  1998年   2116篇
  1997年   1678篇
  1996年   1149篇
  1995年   1080篇
  1992年   3841篇
  1991年   3901篇
  1990年   3627篇
  1989年   3612篇
  1988年   3493篇
  1987年   3313篇
  1986年   3121篇
  1985年   2995篇
  1984年   2061篇
  1983年   1798篇
  1982年   991篇
  1979年   1915篇
  1978年   1184篇
  1977年   986篇
  1975年   1191篇
  1974年   1358篇
  1973年   1413篇
  1972年   1357篇
  1971年   1247篇
  1970年   1137篇
  1969年   1121篇
  1968年   1024篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
OBJECTIVE: To compare mid-gestation sonographic measurements of all five digits of the hands of fetuses with Down syndrome with those of normal controls. METHODS: Twenty-nine fetuses between 17 and 26 weeks' gestation which had been confirmed by karyotyping to have Down syndrome were included in this prospective study. Each fetus was scanned once and the digits of only one hand were measured. Measurements were compared with those of 302 previously reported normal controls matched for gestational age. All measurements were expressed in multiples of the gestation-specific normal median (MoM) for each digit. RESULTS: Compared to 1 MoM for the length of Digits 1 to 5 from the normal population, the respective values in the Down syndrome digits were: 0.94, 0.85, 0.92, 0.88 and 0.85 MoM, representing values significantly lower than normal (P < 0.05; t-test). CONCLUSIONS: All five digits of the hands of fetuses with Down syndrome are shorter than are those of euploid fetuses. Integration of fetal digit measurement into the antenatal assessment of selected high-risk cases may be of value although confirmation of our findings should be obtained before this measurement is incorporated into Down syndrome screening in the general population.  相似文献   
92.
93.
94.
95.
96.
97.
98.
Background: Dreaming reported after anesthesia remains a poorly understood phenomenon. Dreaming may be related to light anesthesia and represent near-miss awareness. However, few studies have assessed the relation between dreaming and depth of anesthesia, and their results were inconclusive. Therefore, the authors tested the hypothesis that dreaming during anesthesia is associated with light anesthesia, as evidenced by higher Bispectral Index values during maintenance of anesthesia.

Methods: With approval, 300 consenting healthy patients, aged 18-50 yr, presenting for elective surgery requiring relaxant general anesthesia with a broad range of agents were studied. Patients were interviewed on emergence and 2-4 h postoperatively. The Bispectral Index was recorded from induction until the first interview. Dream content and form were also assessed.

Results: Dreaming was reported by 22% of patients on emergence. There was no difference between dreamers and nondreamers in median Bispectral Index values during maintenance (37 [23-55] vs. 38 [20-59]; P = 0.68) or the time at Bispectral Index values greater than 60 (0 [0-7] vs. 0 [0-31] min; P = 0.38). Dreamers tended to be younger and male, to have high home dream recall, to receive propofol maintenance or regional anesthesia, and to open their eyes sooner after surgery. Most dreams were similar to dreams of sleep and were pleasant, and the content was unrelated to surgery.  相似文献   

99.
Little is known about the effects of immunosuppression on patients with hereditary nonpolyposis colorectal cancer (HNPCC). We describe a kidney transplant recipient with unrecognized Muir-Torre syndrome in whom the administration of a tacrolimus-based regimen led to the eruption of multiple sebaceous tumors. The patient was later found to harbor an MSH2 mutation. Switching to a sirolimus-based regimen resulted in arrest of the disease. When the patient was switched back to tacrolimus, new facial lesions rapidly appeared. Switching again to sirolimus resulted again in halting the appearance of new lesions. This finding is in line with the known antiangiogenic activity of sirolimus and reports on the regression of cutaneous Kaposi's sarcoma in kidney transplant recipients switched from another immunosuppressive regimen to sirolimus. Further studies on the potential use of sirolimus for the treatment of de novo tumors in immunosuppressed kidney transplant recipients with HNPCC are warranted.  相似文献   
100.
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