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   12909篇
  免费   916篇
  国内免费   48篇
耳鼻咽喉   339篇
儿科学   588篇
妇产科学   384篇
基础医学   1566篇
口腔科学   409篇
临床医学   1219篇
内科学   2547篇
皮肤病学   196篇
神经病学   1335篇
特种医学   729篇
外科学   1391篇
综合类   217篇
一般理论   26篇
预防医学   1031篇
眼科学   382篇
药学   594篇
中国医学   10篇
肿瘤学   910篇
  2021年   139篇
  2020年   106篇
  2019年   136篇
  2018年   196篇
  2017年   124篇
  2016年   154篇
  2015年   151篇
  2014年   235篇
  2013年   354篇
  2012年   478篇
  2011年   502篇
  2010年   260篇
  2009年   286篇
  2008年   424篇
  2007年   513篇
  2006年   501篇
  2005年   441篇
  2004年   429篇
  2003年   396篇
  2002年   439篇
  2001年   424篇
  2000年   418篇
  1999年   351篇
  1998年   169篇
  1997年   143篇
  1996年   156篇
  1995年   149篇
  1994年   166篇
  1993年   108篇
  1992年   372篇
  1991年   380篇
  1990年   374篇
  1989年   345篇
  1988年   359篇
  1987年   371篇
  1986年   330篇
  1985年   307篇
  1984年   202篇
  1983年   196篇
  1982年   124篇
  1981年   119篇
  1980年   104篇
  1979年   198篇
  1978年   176篇
  1977年   126篇
  1976年   107篇
  1975年   120篇
  1974年   127篇
  1973年   126篇
  1972年   111篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
We have compared levels of albumin and serum amino acids in a group of 87 recent admissions to a nursing home, average age 83 years, with a group of healthy moderately old subjects, average age 69 years. We found that the nursing home group was characterized by decreased levels of albumin, by increased total levels of the measured amino acids, and by increased levels of the nonessential amino acids. In contrast, there were no significant group differences in the essential amino acids. Among the nursing home patients, there was a negative correlation between essential amino acids and disability, consistent with nutritional deficits in the more disabled patients, and a positive correlation between essential amino acids and subjective complaints of pain, suggesting that pain is associated with breakdown or mobilization of endogenous protein stores. Though the nursing home patients had decreased serum levels of tryptophan, there was no association between serum tryptophan or other variables that could be related to the availability of tryptophan for transport into brain, with ratings of either depression or pain. Glutamine levels were significantly increased in the nursing home residents, and among these patients they were positively correlated with measures of cognitive impairment.  相似文献   
32.
The objective of the study was to compare the clinical outcomes at the short-term follow-ups of two novel transobturator mid-urethral sling procedures – the transobturator tape (TOT) procedure and the tension-free vaginal tape (TVT)-obturator procedure. The study cohort consisted two groups of 40 women with urodynamically proven stress urinary incontinence (SUI). The patients in one group underwent the TOT procedure, performed according to Delorme (Prog Urol 11:1306–1313, 2001); those in the second group underwent the TVT-obturator operation, performed according to de Leval (Eur Urol 44:724–730, 2003). Intra-operative diagnostic cystoscopy was not performed with either the TVT-obturator or the TOT procedures. The average follow-up was 12 months. The two patient groups were similar in terms of demographic and therapeutic criteria, except for patient age, which was significantly younger in the TVT-obturator group. Previously reported TVT-related operative complications, such as bladder penetration, intra-operative bleeding, field infection and post-operative pelvic floor relaxation, were not observed in patients of either group. Bowel and urethral injuries were also not recorded. The therapeutic failure rates were 10% for the TOT procedure and 5% for the TVT-obturator procedure. Urinary frequency and urgency post-operatively were reported in 25% of the TOT patients and 19% of the TVT-obturator patients, pelvic or vaginal pain affected 10% of the TOT and 5% of the TVT-obturator patients, while post-operative voiding difficulty was experienced by 12.5% of the TOT and 7.5% of the TVT-obturator patients. None of the above-mentioned differences between the two patient groups were of statistical significance. The TVT-obturator and TOT procedures, both minimally invasive, novel, mid-urethral sling procedures, seem to be safe, easy-to-perform and effective in treating female SUI. The patients of both study groups suffered less intra- and post-operative surgical complications than previously been reported in connection with the TVT operation. The TVT-obturator patients had fewer therapeutic failures, less post-operative urinary frequency and urgency, less pelvic pain and less voiding difficulty. All of these findings, however, had no statistical significance; consequently, long-term comparative data collection will be required before solid conclusions can be drawn on the superiority of either of these two operative techniques.  相似文献   
33.
Psychoeducational findings among children treated for phenylketonuria   总被引:2,自引:0,他引:2  
Early treated phenylketonuric children who maintained a phe-restricted diet through age 10 were compared with those who discontinued the diet after age 6 on standardized tests of intelligence, school achievement, language, and perceptual skills. Mean IQ, reading, and spelling test scores improved between ages 6 and 10 for the on-diet children in comparison to those who were off diet. Mean scores on arithmetic, language, and perceptual skills, however, declined at a uniform rate for both groups. Children with PKU scored significantly lower than did their non-PKU siblings on tests of visual perception and visual-motor skills. We conclude that children with PKU should be maintained on a phe-restricted diet.  相似文献   
34.
本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4~5.6%,血浓69.6~1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。  相似文献   
35.
The federal Medicare Diagnosis Related Group payment mechanism is undergoing constant change. Significant interest has been generated at the health policy level regarding reimbursement for patients with complications and comorbidities. The purpose of this study was to analyze hospital resource consumption for patients in the seventeen urology non-complicating condition (CC) stratified Diagnostic Related Groups (DRGs), currently 45 percent of urology DRGs. We analyzed 185 Medicare patients in these non-CC stratified urology DRGs and found that patients with more CCs per patient had higher total hospital costs per patient, financial risk under DRGs, a greater percentage of outliers, and a higher mortality, than patients in these same DRGs with fewer CCs per patient. These findings suggest that the current DRG system is inequitable to some patients and certain hospitals vis-a-vis non-CC stratified urology DRGs. The Health Care Financing Administration has not significantly changed the complicating condition urology DRG classification, as of its recent May, 1988 legislation. Financial disincentives to treat these patients may affect both their access and quality of care in the future.  相似文献   
36.
37.
38.
Computed tomography (CT) has become essential in the diagnostic evaluation of the female pelvic. CT allows accurate delineation of neoplastic and inflammatory processes and provides an effective means of guiding percutaneous needle biopsy of masses and aspiration/drainage of fluid collections. In the pregnant woman, pelvimetry and excretory urography can be performed using the CT scout view with a radiation dose significantly lower than with conventional x-ray techniques. This paper covers the clinically relevant technical considerations involved in performing CT on women and follows with an overview of normal female pelvic anatomy and frequently encountered pathologic conditions.  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