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   3683篇
  免费   132篇
  国内免费   12篇
耳鼻咽喉   27篇
儿科学   525篇
妇产科学   75篇
基础医学   348篇
口腔科学   56篇
临床医学   237篇
内科学   730篇
皮肤病学   60篇
神经病学   151篇
特种医学   155篇
外科学   660篇
综合类   70篇
预防医学   137篇
眼科学   83篇
药学   230篇
  3篇
中国医学   13篇
肿瘤学   267篇
  2023年   25篇
  2022年   35篇
  2021年   79篇
  2020年   43篇
  2019年   81篇
  2018年   121篇
  2017年   70篇
  2016年   99篇
  2015年   78篇
  2014年   122篇
  2013年   143篇
  2012年   249篇
  2011年   252篇
  2010年   156篇
  2009年   94篇
  2008年   186篇
  2007年   199篇
  2006年   187篇
  2005年   160篇
  2004年   141篇
  2003年   143篇
  2002年   141篇
  2001年   89篇
  2000年   85篇
  1999年   69篇
  1998年   38篇
  1997年   30篇
  1996年   26篇
  1995年   22篇
  1994年   24篇
  1993年   11篇
  1992年   59篇
  1991年   60篇
  1990年   37篇
  1989年   36篇
  1988年   29篇
  1987年   30篇
  1986年   34篇
  1985年   36篇
  1984年   30篇
  1983年   16篇
  1981年   25篇
  1980年   15篇
  1979年   22篇
  1978年   21篇
  1977年   30篇
  1976年   29篇
  1975年   12篇
  1974年   14篇
  1968年   13篇
排序方式: 共有3827条查询结果,搜索用时 15 毫秒
991.
992.
O'Donnell B  Puri P 《The Journal of urology》2002,167(4):1808-9; discussion 1810
Thirteen girls with grade III-V vesicoureteric reflux were treated by endoscopic injection of Teflon paste behind the intravesical ureter. Fourteen of the 18 treated ureters showed complete absence of reflux after one injection of Teflon. Three ureters required a second injection of Teflon for successful treatment of the reflux. One ureter with grade IV reflux was converted to grade II reflux. Properly carried out, this procedure corrects reflux. It takes less than 15 minutes, may be done as a day procedure, and avoids open surgery. There have been no complications. (Reprinted with permission from Br Med J, 289: 7-9, 1984)  相似文献   
993.
BACKGROUND AND PURPOSE: Qualitative decreases in maternal brain size have been observed late in pregnancy. The aim of this study was to quantitatively evaluate changes to the maternal brain during and after healthy pregnancy and to compare these changes with those observed in cases of preeclampsia. METHODS: Three-dimensional T1-weighted MR volume images were obtained in nine healthy participants before and after delivery. Additional images were obtained in some of these participants before pregnancy, during pregnancy, and within 52 weeks after delivery. Five women with preeclampsia were examined before delivery and 6 weeks after delivery. Three of these patients were examined within 52 weeks after delivery. Images were registered, and both brain and ventricular volumes were calculated by using a semiautomated computer program. RESULTS: Both the healthy and preeclamptic groups had a reduction in brain size during pregnancy that was maximal at term and that reversed by 6 months after delivery. The ventricular size showed a corresponding increase in size during pregnancy and a decrease in size after delivery. In the preeclamptic patients, brain size was significantly smaller (P =.05) than in healthy participants, both before and after delivery. CONCLUSION: The brain decreases in size during pregnancy and increases in size after delivery. The changes follow a consistent time course in each woman. The mechanism and physiologic importance of these findings are speculative at the present time.  相似文献   
994.
995.
BACKGROUND: The present study was conducted to investigate whether catecholamines influence the production of chemokines and adhesion molecules in proximal tubular epithelial cells (PTECs) and endothelial cells. METHODS: PTECs and human umbilical vein endothelial cells (HUVECs) were stimulated with various concentrations of dopamine (DA), adrenaline (AD), or noradrenaline (NA), and the production of interleukin (IL)-8, ENA-78, and Gro-alpha was assessed by ELISA. The influence of catecholamine pretreatment on tumor necrosis factor (TNF)-alpha-mediated production of these chemokines and the expression of adhesion molecules was also tested. RESULTS: In PTECs, DA inhibited the production of all three chemokines in a dose-dependent fashion. Although inhibition in ENA-78 and Gro-alpha production was also found in HUVECs, IL-8 production was up-regulated in these cells. Increased IL-8 secretion was predominantly observed at the apical site of the cells. In AD or NA stimulated cells, the production of Gro-alpha was increased in PTECs and decreased in HUVECs. Down-regulation in IL-8 production was also observed after AD but not after NA stimulation of both cell types. Interestingly, TNF-alpha-mediated up-regulation in intercellular adhesion molecule 1, vascular cell adhesion molecule (VCAM), and E-selectin was delayed in DA-pretreated HUVECs but not in PTECs. The influence of DA, but not AD or NA, on chemokine production was completely prevented by the addition of N-acetylcysteine. CONCLUSIONS: This study demonstrates that catecholamines differentially influence chemokine production and indicates that DA may have anti-inflammatory properties because it delays the expression of adhesion molecules and inhibits the production of chemokines in PTECs and endothelial cells under basal and inflammatory conditions.  相似文献   
996.
3-O-substituted benzyl pyridazinone derivatives as COX inhibitors   总被引:1,自引:0,他引:1  
New 3-O-substituted benzyl pyridazinone compounds have been synthesised and evaluated for their cyclooxygenase inhibitory activity and COX-2 selectivity. Among the compounds synthesised, three compounds (11b-11d) have shown in vitro COX-2 selectivity. These compounds have been evaluated for their in vivo potential using carrageenan-induced rat paw edema assay. One compound (11b) showed 32% anti-inflammatory activity at 30 mgkg(-1) dose.  相似文献   
997.
We retrospectively analyzed clinicopathological findings in 10 cases of primary malignant melanoma of the vagina. The main presenting symptoms were vaginal bleeding, vaginal discharge, and feeling of a mass. The tumors were predominantly located in the lowest one-third and in the anterolateral aspect of the vagina. Patients underwent various surgical procedures, radiation therapy, and chemotherapeutic modalities. The mean survival time and the recurrence time from the time of diagnosis were 15 and 8 months, respectively. The tumors were examined for histological characteristics of cell type, presence of melanin pigment, depth of invasion, vascular invasion, intraepithelial spread, junctional activity, and mitotic count. Of all these histological variables, the mean survival time had a significant correlation to mitotic count (P less than 0.04). We concluded that patients with lower mitotic counts (less than 6 per 10 HPF) had better survival (21 months) compared to patients with mitotic counts greater than 6 per 10 HPF who had a mean survival of only 7 months.  相似文献   
998.
999.
A patient with residual ectopic pregnancy after salpingostomy was treated with the anti-P RU 486. This did not result in lowered hCG levels, which subsequently resolved after treatment with methotrexate.  相似文献   
1000.
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