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   26794篇
  免费   5359篇
  国内免费   92篇
耳鼻咽喉   139篇
儿科学   546篇
妇产科学   1750篇
基础医学   1128篇
口腔科学   359篇
临床医学   15754篇
内科学   4178篇
皮肤病学   189篇
神经病学   1081篇
特种医学   453篇
外科学   2157篇
综合类   74篇
一般理论   2篇
预防医学   1925篇
眼科学   182篇
药学   623篇
中国医学   9篇
肿瘤学   1696篇
  2024年   82篇
  2023年   805篇
  2022年   166篇
  2021年   371篇
  2020年   676篇
  2019年   289篇
  2018年   1167篇
  2017年   1426篇
  2016年   1513篇
  2015年   1572篇
  2014年   1631篇
  2013年   1933篇
  2012年   720篇
  2011年   986篇
  2010年   1210篇
  2009年   1509篇
  2008年   954篇
  2007年   890篇
  2006年   865篇
  2005年   806篇
  2004年   754篇
  2003年   668篇
  2002年   623篇
  2001年   801篇
  2000年   602篇
  1999年   706篇
  1998年   690篇
  1997年   776篇
  1996年   708篇
  1995年   641篇
  1994年   483篇
  1993年   388篇
  1992年   491篇
  1991年   457篇
  1990年   472篇
  1989年   403篇
  1988年   330篇
  1987年   287篇
  1986年   274篇
  1985年   282篇
  1984年   190篇
  1983年   182篇
  1982年   110篇
  1981年   139篇
  1979年   143篇
  1978年   90篇
  1977年   102篇
  1976年   91篇
  1973年   81篇
  1972年   131篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
Kathleen Rich MS  RN  CCNS 《Journal of Vascular Nursing》2002,20(4):125-35; quiz 136-7
Transcutaneous oxygen (TcPO(2)) measurements provide a noninvasive, objective determination of the oxygen level at the skin surface. This offers a means of estimating the underlying circulation and tissue oxygenation. The purpose of the pilot study was to measure the TcPO(2) value of the lower extremity of healthy men and women and of patients with peripheral arterial disease (PAD) in 4 different body and leg positions 24 hours after peripheral vascular surgery reconstruction. The specific aim was to determine if lower-extremity TcPO(2) measurements were affected by changes in extremity position in these subject populations. A convenience sample of 4 healthy health care professionals and 4 patients who had peripheral vascular reconstruction surgery 24 hours before the measurements were studied. Subjects were studied in 4 different leg and body positions: supine with legs extended, sitting with legs dependent, a 5 degrees head-up reverse Trendelenburg, and supine with legs elevated 10 in. The Radiometer TCM30 TcPO(2) monitor was used to carry out these measures. Findings revealed a statistically significant difference in TcPO(2) measurements between the 2 groups, with the healthy subjects having a significantly higher TcPO(2) measurement in all extremity positions compared with the revascularized subjects with PAD (P =.02-.05). Significant changes were noted in both the foot temperature (P =.03) and TcPO(2) measurements with extremity positions within the healthy subject group (P =.001). The foot and leg TcPO(2) measurements affect from leg and body position did not reach significance (P =.09) in the subjects with PAD. No change in foot temperature with extremity positioning (P =.42) was noted in the subjects with PAD. This pilot study provides a base in which additional research will be performed with TcPO(2) measurements in both the healthy and revascularized person.  相似文献   
63.
64.
65.
66.
The pharmacokinetics of 1-(tetrahydro-2-furanyl)-5-fluorouracil (FT) and its conversion into 5-fluorouracil (FUra) in liver tissue were studied in ten patients with hepatocellular carcinoma (HCC). The plasma concentration of FT after its intravenous injection (dosage: 800 mg) was computerfitted to a bi-exponential function (C = Ae-alpha t + Be-beta t), indicating a two-compartment disposition. The pharmacokinetic parameters did not significantly differ between the five patients with, and the five without cirrhosis of the liver. The plasma concentrations of FUra likewise showed no significant difference between the two groups. The rates of FT degradation in the liver tissue homogenate were similar for four of the patients with cirrhosis (0.10 +/- 0.05 mumol/g liver protein/30 min) and four of those without it (0.13 +/- 0.05). The rates of cytochrome P-450-dependent FUra formation in the microsomal fraction of liver tissue from two patients (1.1 and 1.3 nmol/mg microsomal protein/30 min) were dramatically reduced to less than half of those of two control subjects (2.4 and 2.7). The estimated rates of FUra formation in the soluble fraction (105,000 X g supernatant fraction) from the two patients (0.1 and 0.13 nmol/mg protein/30 min) were almost identical to those from the controls (0.12 and 0.14), suggesting that the rate in the soluble fraction from HCC patients may not be as strongly affected as the rate in the microsomal fraction.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
67.
Seventy-four 8th- and 10th-grade students attending a private girls' school in Hawaii were queried about their perceptions of and preparation for menstruation using a questionnaire administered in a health education class. Eighty percent had already started menstruating. The most frequently cited perceptions by the respondents referred to both the inconveniences and the normalcy of menstruation. Many were first informed about menstruation by their mothers and stated that they also first informed their mothers when they started menstruating. Surprise, fear, and embarrassment were common initial reactions, while strong negative or positive emotions were more rare. Only 35% wanted boys and girls together during class discussion, but 89% stated that boys needed to be informed about menstruation. The most frequent reasons cited for noncoed settings were the girls' concern about their comfort in openly discussing menstruation. Thirty-eight percent thought parents should inform other siblings when they started menstruation, although almost half gave specific conditions the parents should consider. The majority thought the fifth to sixth grades were the best times to introduce menstruation content.  相似文献   
68.
69.
70.
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