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   1803346篇
  免费   130772篇
  国内免费   3014篇
耳鼻咽喉   26089篇
儿科学   55539篇
妇产科学   49832篇
基础医学   257449篇
口腔科学   51982篇
临床医学   159288篇
内科学   340932篇
皮肤病学   38733篇
神经病学   140936篇
特种医学   71959篇
外国民族医学   370篇
外科学   277646篇
综合类   43332篇
现状与发展   4篇
一般理论   510篇
预防医学   133410篇
眼科学   42451篇
药学   140666篇
  7篇
中国医学   4112篇
肿瘤学   101885篇
  2018年   17387篇
  2016年   15488篇
  2015年   17662篇
  2014年   24644篇
  2013年   36586篇
  2012年   49746篇
  2011年   52467篇
  2010年   30749篇
  2009年   28869篇
  2008年   48923篇
  2007年   52757篇
  2006年   53202篇
  2005年   51332篇
  2004年   49721篇
  2003年   47770篇
  2002年   46123篇
  2001年   86866篇
  2000年   88971篇
  1999年   74740篇
  1998年   20069篇
  1997年   18045篇
  1996年   17978篇
  1995年   16925篇
  1994年   15756篇
  1993年   14908篇
  1992年   59290篇
  1991年   57491篇
  1990年   56513篇
  1989年   54560篇
  1988年   50120篇
  1987年   49063篇
  1986年   46411篇
  1985年   44228篇
  1984年   32972篇
  1983年   28156篇
  1982年   16551篇
  1981年   14791篇
  1979年   31498篇
  1978年   21971篇
  1977年   19139篇
  1976年   17044篇
  1975年   19008篇
  1974年   22872篇
  1973年   21993篇
  1972年   21005篇
  1971年   19629篇
  1970年   18410篇
  1969年   17882篇
  1968年   16002篇
  1967年   14537篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
OBJECTIVES: To assess prospectively the early time course of Transforming Growth Factor beta-1 (TGFbeta-1), basic Fibroblast Growth Factor (bFGF) and Tumor Necrosis Factor alpha (TNFalpha) as possible contributors to restenosis development after angioplasty. DESIGN: Prospective Study. METHODS: The levels of the soluble forms of these factors in the early response to Percutaneous Transluminal Angioplasty (PTA) in the arteries of the lower limb were prospectively assessed. 32 patients with peripheral arterial occlusive disease (PAOD), presenting with intermittent claudication (Fontaine stage IIb) were scheduled for angioplasty treatment. Serum levels of TGFbeta-1, TNFalpha and bFGF were assessed before intervention, 15 and 60 minutes after, 24 hours after as well as 2 and 4 weeks after intervention. We compared the distribution patterns between patients treated with balloon angioplasty and patients who required secondary stent implantation. Endpoint was the development of restenosis within 6 months after interventional treatment, defined as a lumen diameter reduction of more than 50% by ultrasound measurement compared to the result after PTA. RESULTS: The patients who later developed restenosis had significantly higher levels of TGFbeta-1 at 15 minutes, 24 hours and 2 weeks after PTA (p<0.05). TNFalpha and bFGF were only detected in a few patients and no significant change of serum levels was observed. CONCLUSION: The results demonstrate a possible role of TGFbeta-1 in the formation of restenosis after PTA.  相似文献   
993.
994.
995.
AIMS: To study the time and cost involved in the care of newly registered outpatients with Type 2 diabetes mellitus (DM), compared with patients with hypertension and/or hyperlipidaemia (HTL). METHODS: A total of 313 patients with DM and 58 patients with HTL without diabetes were registered on their first visits to 11 diabetes clinics across Japan. The time and cost involved in their care was recorded over the following 5 months. RESULTS: In the first 3 months, there was an extensive time commitment to both groups. The time spent by physicians was 1.5 times longer for DM than for HTL. The total care time spent by all the care providers for DM was twice that for HTL. The cost of DM care was twice that for HTL, with the cost of medicines excluded. However, half of the cost for DM was for laboratory tests. When these were excluded, and the remaining cost divided by the time spent, the amount for DM was half of that for HTL. Over the 5 months, mean glycated haemoglobin (HbA(1c)) in DM patients improved from 8.0% to 6.5%, and 72% of DM patients achieved the glycaemic target of HbA(1c) < or = 6.5%. CONCLUSIONS: DM care in a diabetes clinic requires a great deal more time and resources than HTL to achieve the best outcome. An educational system for self care, presently lacking in the primary care setting in Japan, would improve glycaemic control for DM patients in the community.  相似文献   
996.
For chronic thromboembolic pulmonary hypertension not amenable to pulmonary endarterectomy, effective medical therapy is desired. In an open-label uncontrolled clinical trial, 104 patients (mean +/- sem age 62 +/- 11 yrs) with inoperable chronic thromboembolic pulmonary hypertension were treated with 50 mg sildenafil t.i.d. At baseline, patients had severe pulmonary hypertension (pulmonary vascular resistance 863 +/- 38 dyn.s.cm(-5)) and a 6-min walking distance of 310 +/- 11 m. Eight patients were in World Health Organization functional class II, 76 in class III and 20 in class IV. After 3 months' treatment, there was significant haemodynamic improvement, with reduction of pulmonary vascular resistance to 759 +/- 62 dyn.s.cm(-5). The 6-min walking distance increased significantly to 361 +/- 15 m after 3 months' treatment, and to 366 +/- 18 m after 12 months' treatment. A subset of 67 patients received a single dose of 50 mg sildenafil during initial right heart catheterisation. The acute haemodynamic effect of this was not predictive of long-term outcome. In this large series of patients with inoperable chronic thromboembolic pulmonary hypertension, open-label treatment with sildenafil led to significant long-term functional improvement. The acute effect of sildenafil may not predict the long-term outcome of therapy.  相似文献   
997.
The aqueous extract of the fruits of Terminalia chebula Retz. has been evaluated for its antidiabetic activity in streptozotocin (STZ) induced mild diabetic rats and compared with a known drug, tolbutamide. The oral effective dose (ED) of the extract was observed to be 200 mg/kg body weight, which produced a fall of 55.6% (p<0.01) in the oral glucose tolerance test. Oral administration of ED of aqueous extract of T.chebula (AETC) daily once for two months reduced the elevated blood glucose by 43.2% (p<0.01) and significantly reduced the increase in glycosylated hemoglobin (HbA1c) (p<0.01). The same dose also showed a marked improvement in controlling the elevated blood lipids as well as decreased serum insulin levels in contrast to the untreated diabetic animals. Hepatic and skeletal muscle glycogen content decreased by 75% and 62.9% respectively in diabetic controls, these alterations were partly prevented (34.9% and 21.17%) in AETC treated group when compared to the healthy controls. The in vitro studies with pancreatic islets showed that the insulin release was nearly two times more than that in untreated diabetic animals. The treatment did not have any unfavorable effect on other blood parameters of liver and kidney function tests. LD 50 was found to be above 3 g/kg bw i.e. 15 times of ED, because there were no deaths of animals even at this dose indicating high margin of safety. These findings suggest further investigations for the possible use of the aqueous extract of fruits of T.chebula for the treatment of diabetes.  相似文献   
998.
999.
LYMPHOGRANULOMA VENEREUM   总被引:3,自引:0,他引:3  
  相似文献   
1000.
A report of 500 cases of lumbar anesthesia is submitted with special reference to the incidence of postanesthetic headache, nausea, and vomiting in patients who are ambulatory within a short period after surgery.
1.
1. Postanesthetic headache occurred in 30.6 per cent of the cases; this is a much higher incidence than one finds in most published reports and may be explained upon the basis of the following considerations: cases reported in the literature are not selected cases, but those usually requiring seven to ten days of postoperative bed rest; the cases analyzed in the present study were largely those on whom anorectal operations had been performed, these patients requiring only a short period of recumbency.  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