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   3672篇
  免费   417篇
  国内免费   7篇
耳鼻咽喉   17篇
儿科学   63篇
妇产科学   90篇
基础医学   471篇
口腔科学   73篇
临床医学   476篇
内科学   806篇
皮肤病学   31篇
神经病学   428篇
特种医学   104篇
外科学   441篇
综合类   87篇
一般理论   4篇
预防医学   479篇
眼科学   25篇
药学   278篇
中国医学   3篇
肿瘤学   220篇
  2023年   32篇
  2022年   30篇
  2021年   102篇
  2020年   53篇
  2019年   86篇
  2018年   91篇
  2017年   71篇
  2016年   64篇
  2015年   83篇
  2014年   100篇
  2013年   145篇
  2012年   203篇
  2011年   232篇
  2010年   127篇
  2009年   100篇
  2008年   183篇
  2007年   185篇
  2006年   177篇
  2005年   174篇
  2004年   176篇
  2003年   131篇
  2002年   113篇
  2001年   92篇
  2000年   86篇
  1999年   76篇
  1998年   46篇
  1997年   26篇
  1994年   31篇
  1993年   25篇
  1992年   73篇
  1991年   56篇
  1990年   53篇
  1989年   55篇
  1988年   52篇
  1987年   35篇
  1986年   43篇
  1985年   45篇
  1984年   44篇
  1983年   25篇
  1982年   27篇
  1979年   32篇
  1978年   29篇
  1976年   26篇
  1974年   24篇
  1973年   29篇
  1972年   30篇
  1971年   25篇
  1969年   28篇
  1968年   34篇
  1966年   34篇
排序方式: 共有4096条查询结果,搜索用时 15 毫秒
1.
2.
Despite significant improvements in the prognosis of acute promyelocytic leukemia brought about by therapeutic advances, understanding of the epidemiology of acute promyelocytic leukemia remains limited. Earlier reports have suggested that Hispanics may have an increased incidence of acute promyelocytic leukemia, but no systematic analysis of national data has yet been reported. We performed a retrospective cohort study, using data from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute from 1992-2001 in order to compare leukemia incidence rates as a function of race and ethnicity. We identified 709 cases of acute promyelocytic leukemia and analyzed incidence rates by race and sex. Hispanics were not found to have greater lifetime incidence rates than whites, with an incidence relative rate (IRR) of 0.86 that of whites (P=0.17). The age distribution among Hispanics was significantly different from non-Hispanic whites, with greater incidence rates for children ages 1-19 years (IRR=1.9, P=0.02) and adult ages 20-44 years (IRR=1.6, P=0.004). Blacks had lower lifetime incidence rates than non-Hispanic whites (IRR=0.75, P=0.04), Hispanics (IRR=0.64, P=0.007), and Asians (IRR=0.67, P=0.03). Asians did not differ from non-Hispanic whites in lifetime or age-specific incidence rates. These results indicate that while US Hispanics do not have greater lifetime incidence rates of acute promyelocytic leukemia, blacks have lower incidence rates of acute promyelocytic leukemia than Hispanics, non-Hispanic whites, and Asians.  相似文献   
3.
Two different regimens of cephalosporin antibiotic prophylaxis were compared with antiseptic lubricating jelly to try to prevent infection and complications in 196 men after prostatic surgery. Pre-operative urine was cultured and prostatic chips (170 cases) were also cultured to define the source of any infection. The use of antibiotics was associated with a reduced risk of postoperative bacteriuria. No serious complications occurred, although 1 patient in the antiseptic treated group developed rigors; 79 of 170 patients (46%) had positive prostatic chip cultures, of whom 74 had sterile pre-operative urine. There was no association between the result of chip culture and the presence of a pre-operative catheter. Culture positive patients had an increased risk of post-operative urine infection, although the same organism was found in the prostate and urine in only 36% of cases of post-operative bacteriuria and in 43 (54%) the organism cultured from the prostate was Staphylococcus albus. This study provides further evidence of the benefit of true prophylactic antibiotic therapy for transurethral prostatic surgery and the prostatic chip data suggest that some of the risk is due to pre-operative contamination of the prostate in the absence of per-operative urinary infection or catheterisation.  相似文献   
4.
A range of 18 derivatives of flavone-8-acetic acid (FAA) with substituents on the 2-phenyl group have been prepared and their anti-tumour activity evaluated in vitro against a panel of human and murine tumour cell lines and in vivo against MAC 15A. There was no clear-cut relationship between in vitro and in vivo activity but the activity in each situation was found to be very sensitive to the precise substitution pattern with closely related isomers giving widely different activities. Some of the compounds, notably 10b,cj , and r , were active in vivo and these require further studies in order to evaluate their potential for development.  相似文献   
5.
6.
One thousand two hundred and fifty-four adolescents in Hamilton, New Zealand, ranging in age from 10 to 16, were questioned on their awareness of, and attitudes towards, cigarette advertising, and on their image of the young smoker. Most of the respondents felt that tobacco companies advertise to encourage people to buy their brands. Smokers were less likely than non-smokers to feel that cigarette companies advertise to encourage young people to take up smoking. They were also more likely to agree that cigarette companies are generous, public spirited people. Non-smokers were more likely to feel that cigarette advertising was effective in encouraging young people to smoke. Winfield, the most popular brand among smokers, was also the most well known. Smokers had a more positive image than non-smokers of the young person who smokes.  相似文献   
7.
We have used a vaginal speculum to insert a testicular prosthesis through the inguinal approach over the past four years. We have found this technique to be easily performed and reproducible in allowing the testicular prosthesis to be placed in the normal dependent position in the scrotum.  相似文献   
8.
9.
10.
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