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   2235篇
  免费   145篇
  国内免费   19篇
耳鼻咽喉   58篇
儿科学   48篇
妇产科学   28篇
基础医学   316篇
口腔科学   189篇
临床医学   143篇
内科学   391篇
皮肤病学   38篇
神经病学   142篇
特种医学   150篇
外科学   301篇
综合类   10篇
一般理论   2篇
预防医学   270篇
眼科学   29篇
药学   151篇
中国医学   20篇
肿瘤学   113篇
  2023年   22篇
  2022年   45篇
  2021年   88篇
  2020年   59篇
  2019年   61篇
  2018年   99篇
  2017年   79篇
  2016年   74篇
  2015年   84篇
  2014年   127篇
  2013年   135篇
  2012年   202篇
  2011年   189篇
  2010年   113篇
  2009年   73篇
  2008年   107篇
  2007年   115篇
  2006年   114篇
  2005年   77篇
  2004年   77篇
  2003年   60篇
  2002年   42篇
  2001年   26篇
  2000年   19篇
  1999年   22篇
  1998年   19篇
  1997年   12篇
  1996年   17篇
  1995年   17篇
  1994年   11篇
  1993年   4篇
  1992年   12篇
  1991年   11篇
  1990年   15篇
  1989年   16篇
  1988年   14篇
  1987年   23篇
  1986年   10篇
  1985年   9篇
  1984年   4篇
  1983年   11篇
  1982年   14篇
  1981年   11篇
  1980年   14篇
  1979年   9篇
  1978年   5篇
  1977年   5篇
  1976年   7篇
  1971年   4篇
  1969年   5篇
排序方式: 共有2399条查询结果,搜索用时 156 毫秒
1.
2.
3.
4.
5.
6.
In a prospective, randomized, double-blind study, 49 patients underwent lumbar myelography using iotrol (24 patients) or metrizamide (25 patients). The diagnostic imaging adequacy of iotrol was comparable with that of metrizamide. After iotrol myelography, adverse reactions were fewer, less severe, and of shorter duration than were those following metrizamide myelography. Thirteen of 24 patients (54%) receiving iotrol reported some adverse reactions compared with 24 of 25 patients (96%) receiving metrizamide. Five moderate and one severe adverse reaction occurred in the group receiving iotrol. Fourteen moderate and eight severe adverse reactions occurred in the group receiving metrizamide. Thirty-eight patients underwent electroencephalography both before and after myelography (19 iotrol and 19 metrizamide). None of the EEGs obtained after iotrol myelography changed from baseline, while seven of the EEGs obtained after metrizamide myelography showed changes from baseline. Iotrol was judged superior to metrizamide as a contrast medium in this patient population.  相似文献   
7.
8.
After total gastrectomy, the ileocecal graft may act as a reservoir and protect against reflux but give rise to transposition of the ileum and cause possible changes in bile acid metabolism and nutrition. This study compared the ileocecal graft and jejunal pouch. Male Wistar rats weighing 265 +/- 22 g were submitted to sham operation (S), ileocecal interposition graft (IIG), and jejunal pouch interposition graft (JP) after total gastrectomy. Eight weeks later, the esophagus was examined for evidence of esophagitis. Nutritional biochemistry and weight profile were documented preoperatively and 8 weeks after surgery. The oral glucose tolerance test was performed. Thirty-three rats were operated on and 30 survived for 8 weeks. Esophagitis occurred in seven JP rats. Body weight was significantly higher in IIG than in JP rats (p < .05). Normal glucose tolerance to intragastric glucose load was observed in sham and operated rats. JP rats had a significant decrease in serum albumin, glucose, transferrin, hemoglobin, iron, folate, and calcium, compared to sham (p < .05). Cobalamine was significantly lower in IIG rats than in JP rats (p < .05). In the IIG and JP groups, serum/hepatic total bile acid did not differ significantly from preoperative and sham values. In conclusion, the IIG interposition graft in rats prevented esophagitis, preserved nutrition, and did not interfere with enterohepatic total bile acid circulation.  相似文献   
9.
10.
Sequential two-dimensional (2-D) inflow MR-angiography (SDSMRA) utilizes the bloodflow-induced changes in the MR-signal for intraluminal vessel contrast. To assess the effect of the peripheral arterial flowpulse on the average intraluminal MR-signalintensity (MIMRSI) seven healthy subjects, mean age 31 +/- 4 years, were studied using color Doppler flow mapping and SDSMRA. In each subject the regional MIMRSI was measured in 21 vascular segments and correlated with the regional flowpulse in a simple regression model. MIMRSI ranged from 915 +/- 299 in the right profunda femoris to 1378 +/- 283 in the distal abdominal aorta: distally, the trifurcation it was, with the exception of the posterior tibial artery in three subjects (MIMRSI = 545 +/- 64), not measurable. The regional differences in the peripheral flowpulse were without statistically measurable effect on MIMRSI. MIMRSI was best correlated to the systolic forward flow in 14, to the backward flow in 3, and to the mean forward flow in 1 vascular segment, respectively. The mean correlation coefficient (r) was 0.56, ranging from r = 0.11 in the right popliteal artery to r = 0.93 in the right superficial femoral artery. In the distal abdominal aorta no positive correlation between the blood flow and MIMRSI was determined. The regional differences in the peripheral arterial flow-pulse have no significant effect on MIMRSI in healthy men. MIMRSI correlates best with the systolic forward flow. However, on the average, 44% of the MIMRSI appear to be related to flow-independent yet unidentified factors. Optimal design of SDSMRA pulse sequences will require a better characterization of flow-dependent and flow-independent MIMRSI parameter.  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