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   2169篇
  免费   121篇
  国内免费   58篇
耳鼻咽喉   13篇
儿科学   110篇
妇产科学   24篇
基础医学   208篇
口腔科学   35篇
临床医学   317篇
内科学   437篇
皮肤病学   52篇
神经病学   77篇
特种医学   313篇
外科学   204篇
综合类   45篇
预防医学   279篇
眼科学   11篇
药学   127篇
中国医学   3篇
肿瘤学   93篇
  2021年   26篇
  2020年   21篇
  2019年   18篇
  2018年   29篇
  2016年   23篇
  2015年   30篇
  2014年   38篇
  2013年   69篇
  2012年   61篇
  2011年   54篇
  2010年   55篇
  2009年   78篇
  2008年   57篇
  2007年   97篇
  2006年   64篇
  2005年   59篇
  2004年   58篇
  2003年   52篇
  2002年   54篇
  2001年   38篇
  2000年   36篇
  1999年   37篇
  1998年   85篇
  1997年   94篇
  1996年   107篇
  1995年   70篇
  1994年   71篇
  1993年   59篇
  1992年   45篇
  1991年   39篇
  1990年   52篇
  1989年   67篇
  1988年   54篇
  1987年   47篇
  1986年   59篇
  1985年   53篇
  1984年   20篇
  1983年   36篇
  1982年   22篇
  1981年   14篇
  1980年   19篇
  1979年   25篇
  1978年   24篇
  1977年   16篇
  1976年   16篇
  1975年   20篇
  1974年   12篇
  1973年   13篇
  1930年   12篇
  1926年   11篇
排序方式: 共有2348条查询结果,搜索用时 15 毫秒
1.
2.
3.
Incidence of hypertension in the Framingham Study.   总被引:6,自引:1,他引:5       下载免费PDF全文
Incidence and trends in incidence of definite hypertension were analyzed based on 30 years follow-up of 5,209 subjects in the Framingham Heart Study cohort. Based on pooling of 15 two-year periods, hypertension incidence per biennium increased with age in men from 3.3 per cent at ages 30-39 to 6.2 per cent at ages 70-79, and in women from 1.5 per cent at ages 30-39 to 8.6 per cent at ages 70-79. No consistent trend in incidence rates was evident for either sex from the 1950s through the 1970s. The proportion of hypertensive subjects receiving antihypertensive medication has increased since 1954-58 and exceeded 80 per cent for both men and women ages 60-89 years in 1979-81. Incidence data presented in this report may serve as a baseline for assessing the impact of future public health efforts in the primary prevention of hypertension.  相似文献   
4.
R W Evans  D L Manninen  L P Garrison  A M Maier 《JAMA》1986,255(14):1892-1898
Heart transplantation has now achieved a therapeutic status similar to that of cadaveric renal transplantation. Depending on patient selection criteria, it is estimated that as many as 15,000 people per year could conceivably benefit from a heart transplant, but the actual number of persons who will benefit is severely constrained by donor supply. Availability of heart donors was estimated based on data obtained on 1,955 organ donors in the United States. The results show that because of age and other contraindications, only 400 to 1,100 viable donor hearts may be available each year. Donor supply is the most critical determinant of the future of heart transplantation since it will dictate the number of transplants performed, the survival of transplant recipients, the total program expenditures associated with heart transplantation, the nature of the legal and ethical issues involved, the number of cardiac transplant programs required to make optimal use of the available donor hearts, and the future role of mechanical circulatory support systems.  相似文献   
5.
Operative cholangiography   总被引:3,自引:0,他引:3  
The value of operative cholangiography in the management of biliary tract disease has been questioned. To better define the role of cholangiography, we reviewed 579 consecutive cholecystectomies done by 1 group of surgeons in a small rural practice over 8 years. Cholangiography demonstrated unsuspected common bile duct disease in 5% of the procedures, while 12% of the patients were spared an unnecessary choledochotomy after a normal cholangiogram was obtained. There was no morbidity, mortality, or prolongation of the hospital stay attributed to the cholangiographic procedure. These findings bolster the argument for routine cholangiography as a safe, effective, and helpful screening examination for patients who are at risk for having common bile duct disease.  相似文献   
6.
7.
8.
9.
BACKGROUND: Since 1997, a number of trials have shown promising results in treating generalized vitiligo with narrowband ultraviolet B (UVB) both in adults and children. However, there is little knowledge concerning the duration and permanency of the treatment-induced repigmentation. OBJECTIVE: Our main objective was to perform a follow-up trial of successfully treated patients receiving narrowband UVB for generalized vitiligo. METHODS: We have investigated to what degree the treatment-induced repigmentation remains stable for up to 2 years post-treatment. We performed an initial open trial including 31 patients with generalized vitiligo. They received narrowband UVB thrice weekly for up to 12 months. Patients experiencing > 75% repigmentation were defined responders and were included in the follow-up trial. Responders were followed every 6 months for up to 2 years after cessation of treatment. We observed the pigmentation status and registered any changes indicating loss of pigmentation and relapse. RESULTS: Eleven of the 31 treated patients were included in the follow-up trial. Six patients had relapse and five patients had stable response 24 months after cessation of treatment. Four out of six relapses were within 6 months post-treatment. CONCLUSION: In our study population of 31 patients with generalized vitiligo, five patients (16%) experienced > 75% stable repigmentation 2 years after cessation of a treatment programme of up to 1 years narrowband UVB therapy.  相似文献   
10.
We report two clinical pregnancies occurring after intracytoplasmic sperm injection (ICSI) using cryopreserved spermatozoa obtained from testicular biopsy, made in two different infertility situations in our clinic. The first patient showed a secretory azoospermia associated with elevated serum follicular stimulating hormone (FSH) level and spermiogenesis maturation arrest. The second patient was affected by azoospermia resulting from bilateral epididymal obstruction. Spermatozoa present in the wet preparation of testicular biopsy made on the day of scrotal exploration were cryopreserved within the testicular tissue for both men. Intracytoplasmic injections were performed at a later date, using spermatozoa prepared from frozen-thawed tissues. In each case, three embryos were obtained and transferred in utero. The transfers resulted in a twin pregnancy for the first case, and in a singleton pregnancy for the second. Living foetuses were seen in the ultrasound scan at the 7th week and both pregnancies are proceeding to date beyond 30 weeks without complications.   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