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   1800篇
  免费   267篇
  国内免费   26篇
耳鼻咽喉   16篇
儿科学   46篇
妇产科学   35篇
基础医学   287篇
口腔科学   60篇
临床医学   200篇
内科学   370篇
皮肤病学   34篇
神经病学   277篇
特种医学   93篇
外科学   130篇
综合类   105篇
预防医学   171篇
眼科学   39篇
药学   122篇
中国医学   1篇
肿瘤学   107篇
  2022年   23篇
  2021年   24篇
  2020年   23篇
  2019年   30篇
  2018年   48篇
  2017年   23篇
  2016年   30篇
  2015年   31篇
  2014年   29篇
  2013年   56篇
  2012年   84篇
  2011年   71篇
  2010年   47篇
  2009年   41篇
  2008年   60篇
  2007年   79篇
  2006年   84篇
  2005年   86篇
  2004年   67篇
  2003年   67篇
  2002年   65篇
  2001年   45篇
  2000年   60篇
  1999年   40篇
  1998年   38篇
  1997年   32篇
  1996年   27篇
  1995年   21篇
  1994年   27篇
  1993年   20篇
  1992年   42篇
  1991年   44篇
  1990年   32篇
  1989年   54篇
  1988年   61篇
  1987年   48篇
  1986年   38篇
  1985年   32篇
  1984年   32篇
  1983年   41篇
  1982年   21篇
  1981年   16篇
  1980年   17篇
  1979年   28篇
  1978年   23篇
  1976年   16篇
  1972年   14篇
  1971年   19篇
  1970年   17篇
  1969年   17篇
排序方式: 共有2093条查询结果,搜索用时 14 毫秒
31.
Amblyomma americanum collected near Lake Wappapello, Missouri, tested positive for Borrelia lonestari using polymerase chain reaction and sequence analyses of B. lonestari 16S rRNA and flagellin (flaB) genes. Twelve pools containing a total of 214 nymph or adult ticks contained evidence of infection with B. lonestari (minimum prevalence 5.6%). These data suggest that persons in southeast Missouri are at risk for exposure to B. lonestari after A. americanum tick bite, a possible cause of erythema migrans-like rash illness in this region. Derivation of the complete coding sequence for B. lonestari flaB is also reported.  相似文献   
32.

Background

99mTc-labeled teboroxime shows high myocardial extraction in both in vivo animal and in vitro cell culture and isolated heart studies. Whereas in vivo studies show rapid myocardial clearance of teboroxime, in vitro cell culture and isolated heart studies show slower washout comparable to that of201Tl. Binding of teboroxime to blood components may contribute to these conflicting results.

Methods and Results

We measured teboroxime extraction in the isolated blood-perfused rabbit heart after injection in saline solution, brief incubation in red blood cell perfusate, or 4-hour incubation with human red blood cells. Teboroxime in saline solution showed high extraction (Emax=0.89±0.02; Enet=0.69±0.02), whereas brief incubation in perfusate (Emax=0.60±0.06; Enet=0.48±0.05) or prolonged incubation with human red blood cells (Emax=0.43±0.09; Ene=0.38±0.07) resulted in reduced extraction. Teboroxime clearance was similar for all groups and was slower than201Tl clearance. Analysis of total residual cardiac teboroxime (comparable to external imaging) showed that teboroxime clearance was biexponential. Reduced extraction of teboroxime in red blood cells resulted in an increased size of the rapidly clearing (unextracted) fraction, giving the appearance of rapid myocardial washout.

Conclusions

Teboroxime has a high myocardial extraction. Binding to blood components reduces teboroxime extraction and increases the rate of cardiac teboroxime clearance.  相似文献   
33.
34.
35.
Non-typhoid Salmonella gastroenteritis   总被引:2,自引:0,他引:2  
  相似文献   
36.
A 54-year-old man was treated with weekly 24-h infusion of high-dose 5-fluorouracil (2600 mg/m2) and leucovorin (100 mg/m2) for metastatic colon cancer. At first, he tolerated the treatment well and no significant toxicity was identified. After a total of eight courses of treatment, a stable disease was observed, but mild shortness of breath was found on occasion. The patient had no previous history of cardiac disease and the heart performance assessed by left ventricular ejection fraction before treatment was normal. Unfortunately, acute pulmonary edema with lethal cardiogenic shock occurred during the ninth course of treatment, in spite of intensive medical treatment. The chest X-ray showed extreme cardiomegaly. Repeated assessment of his heart function by echocardiogram and ventricular ejection fraction revealed a very poor cardiac performance. Toxic cardiogenic shock during weekly 24-h infusion of high-dose 5-fluorouracil and leucovorin is extremely rare. To the best of our knowledge, no case has been reported in the English literature. We report a case and the relevant literature about the incidence, clinical picture and possible pathophysiology on 5-fluorouracil-related cardioxicity is reviewed.   相似文献   
37.
PURPOSE: We present our experience with collagen injection for treating urinary incontinence after cystectomy and orthotopic bladder substitution in women. We discuss the efficacy of collagen injection, specific complications and subsequent definitive therapy. MATERIALS AND METHODS: We performed cystectomy and orthotopic bladder substitution in 2 women for muscle invasive transitional cell carcinoma of the bladder. In each case new onset stress urinary incontinence developed after surgery that was refractory to conservative therapy. Intrinsic sphincter deficiency was diagnosed in each patient by video urodynamic studies. Initial treatment involved transurethral collagen injections but subsequent intervention was required due to resultant complications and primary therapy inefficacy. RESULTS: Collagen (3.5 cc per session) was injected in 1 case at 2 treatment sessions and in the other at 3. Incontinence symptoms did not significantly improve in either patient and a new onset vesicovaginal fistula developed 2 days and 1 month after collagen injection, respectively. Subsequently in each case 1-stage transvaginal primary fistula repair was done in multiple layers with a pubovaginal sling procedure. Six months after repair there has been no recurrent fistula and the women remain hypercontinent, requiring intermittent self-catheterization. They are satisfied with their eventual lower tract function and overall outcome. CONCLUSIONS: Collagen injection for type 3 stress urinary incontinence after cystectomy and orthotopic bladder replacement in women may not be as effective and innocuous as in patients with a native bladder. Initial treatment with a pubovaginal sling procedure should be considered.  相似文献   
38.
Polygonum multiflorum stilbeneglycoside (PMS) is a water-soluble fraction of Polygonum multiflorum Thunb. , one of the most famous tonic traditional Chinese medicines, that has protective effects on the cardiovascular system. The purpose of the present study is to elucidate the effects of PMS on macrophage-derived foam cell functions and the reduction of severity of atherosclerosis in hypercholesterolemic New Zealand White (NZW) rabbits. NZW rabbits were fed for 12 weeks with a normal diet, a high cholesterol diet, or a high cholesterol diet associated with irrigation with different doses of PMS (25, 50, or 100 mg/kg). Treatment of NZW rabbits fed with high cholesterol diet with 100 mg/kg PMS attenuated the increase in plasma cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and plasma triglyceride. Treatment with 50 and 100 mg/kg PMS caused 43% and 60% decrease in atherosclerotic lesioned area ratio to total surface area, respectively. In U937 foam cells, PMS could decrease the high expression of intercellular adhesion molecule (ICAM)-1 protein and the vascular endothelial growth factor (VEGF) protein levels in the medium induced by oxidized lipoprotein when analyzed by flow cytometry. The results proved that PMS is a powerful agent against atherosclerosis and that PMS action could possibly be through the inhibition of the expression of ICAM-1 and VEGF in foam cells.  相似文献   
39.
40.
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