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   1742篇
  免费   95篇
  国内免费   57篇
耳鼻咽喉   7篇
儿科学   93篇
妇产科学   20篇
基础医学   192篇
口腔科学   65篇
临床医学   182篇
内科学   369篇
皮肤病学   67篇
神经病学   94篇
特种医学   322篇
外科学   133篇
综合类   33篇
预防医学   103篇
眼科学   20篇
药学   75篇
中国医学   9篇
肿瘤学   110篇
  2023年   11篇
  2022年   16篇
  2021年   22篇
  2020年   15篇
  2019年   39篇
  2018年   42篇
  2017年   19篇
  2016年   15篇
  2015年   27篇
  2014年   37篇
  2013年   65篇
  2012年   60篇
  2011年   43篇
  2010年   56篇
  2009年   66篇
  2008年   47篇
  2007年   95篇
  2006年   40篇
  2005年   51篇
  2004年   42篇
  2003年   30篇
  2002年   31篇
  2001年   31篇
  2000年   20篇
  1999年   33篇
  1998年   71篇
  1997年   87篇
  1996年   103篇
  1995年   66篇
  1994年   60篇
  1993年   57篇
  1992年   22篇
  1991年   27篇
  1990年   25篇
  1989年   47篇
  1988年   42篇
  1987年   37篇
  1986年   47篇
  1985年   52篇
  1984年   17篇
  1983年   19篇
  1982年   17篇
  1981年   13篇
  1980年   17篇
  1979年   15篇
  1978年   14篇
  1977年   13篇
  1976年   16篇
  1975年   16篇
  1974年   9篇
排序方式: 共有1894条查询结果,搜索用时 11 毫秒
1.
2.
Intravenous ganciclovir is the standard treatment for cytomegalovirus disease in solid organ transplant recipients. Oral valganciclovir is a more convenient alternative. In a randomized, international trial, recipients with cytomegalovirus disease were treated with either 900 mg oral valganciclovir or 5 mg/kg i.v. ganciclovir twice daily for 21 days, followed by 900 mg daily valganciclovir for 28 days. A total of 321 patients were evaluated (valganciclovir [n = 164]; i.v. ganciclovir [n = 157]). The success rate of viremia eradication at Day 21 was 45.1% for valganciclovir and 48.4% for ganciclovir (95% CI -14.0% to +8.0%), and at Day 49; 67.1% and 70.1%, respectively (p = NS). Treatment success, as assessed by investigators, was 77.4% versus 80.3% at Day 21 and 85.4% versus 84.1% at Day 49 (p = NS). Baseline viral loads were not different between groups and decreased exponentially with similar half-lives and median time to eradication (21 vs. 19 days, p = 0.076). Side-effects and discontinuations of assigned treatment (18 of 321 patients) were comparable. Oral valganciclovir shows comparable safety and is not inferior to i.v. ganciclovir for treatment of cytomegalovirus disease in organ transplant recipients and provides a simpler treatment strategy, but care should be taken in extrapolating to organ transplant recipients not properly represented in the present study.  相似文献   
3.
4.
We tested 120 consecutive admissions with sputum positive pulmonary tuberculosis for antibodies to the human immunodeficiency virus type I (HIV-1). Pre-treatment chest x-ray appearances were recorded. Seventy one patients (59%) were males and 49 (41%) were females. 43 (35.8%) patients were seropositive for HIV, and were all in the age range 16-45 years. The seropositivity for the 56 males and 44 females in the age range 16-45 years were 53 and 26 percent respectively. Atypical x-ray features were found in 21 of 43 cases compared to 15 of 57 referents (p less than 0.025). Radiographic features typical of reactivation pulmonary tuberculosis in the adult were found in 73% and 51% of referents and cases respectively (P less than 0.025). Pulmonary lesions localized to the mid and or lower zones were seen in 20 percent of cases and 3.3% of referents (P = 0.01). Mediastinal and or hilar adenopathy alone or with pulmonary infiltrates occurred more frequently among cases but the results were not significant. Our findings indicate that radiological appearances of pulmonary tuberculosis in patients seropositive for HIV-1 antibodies tend to be atypical in type of lesion and or anatomic distribution, even for patients from communities with high prevalence rates of tuberculosis.  相似文献   
5.
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   
6.
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   
7.
8.
9.
Thirty-five patients hospitalized for recent angiographically documented arterial occlusion in the legs (27 femoropopliteal arteries and eight grafts) benefited from local fibrinolytic therapy delivered at the site of the occlusion with a 4- or 5-F catheter. This therapy combined a continuous urokinase (UK) infusion of 1,000 U/kg/hour and a lysyl plasminogen (LYS-PLG) infusion of 15 microkatals every 30 minutes. Angiographically confirmed lysis was obtained in 85% of the cases. Only 3% of the patients had major and 6% had minor groin hematomas. Only two patients had concentrations of fibrinogen as low as 100 mg/dl. Intravascular infusion of UK-LYS-PLG is as effective as streptokinase. Its excellent tolerance makes it a good alternative in the treatment of acute ischemia in the lower limbs.  相似文献   
10.
Birnholz  JC 《Radiology》1986,158(3):805-807
Ultrasound (US) can be used to visualize vertebral segments, suggesting a quantitative means of studying vertebral column growth in utero and thus a means of detecting developmental abnormalities. US images of the lumbar spine were obtained in 128 clinically normal fetuses between the gestational age of 11 through 41 weeks. A large-aperture, dynamically focused US system capable of regional magnification was used. Average lumbar spacing was calculated from distance between centrums of at least four lumbar bodies. The average distance between lumbar centrums increased nearly linearly throughout the second and third trimesters (r2 = 0.98). Enhanced anatomic display implies new capabilities for recognizing developmental abnormalities antenatally.  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