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   5645篇
  免费   286篇
  国内免费   15篇
耳鼻咽喉   20篇
儿科学   173篇
妇产科学   65篇
基础医学   824篇
口腔科学   100篇
临床医学   301篇
内科学   1484篇
皮肤病学   33篇
神经病学   332篇
特种医学   173篇
外科学   838篇
综合类   15篇
预防医学   233篇
眼科学   194篇
药学   479篇
中国医学   9篇
肿瘤学   673篇
  2023年   25篇
  2022年   59篇
  2021年   92篇
  2020年   53篇
  2019年   78篇
  2018年   99篇
  2017年   78篇
  2016年   95篇
  2015年   111篇
  2014年   131篇
  2013年   146篇
  2012年   253篇
  2011年   278篇
  2010年   169篇
  2009年   140篇
  2008年   264篇
  2007年   309篇
  2006年   293篇
  2005年   289篇
  2004年   329篇
  2003年   279篇
  2002年   294篇
  2001年   157篇
  2000年   156篇
  1999年   166篇
  1998年   89篇
  1997年   70篇
  1996年   54篇
  1995年   48篇
  1994年   39篇
  1993年   41篇
  1992年   107篇
  1991年   112篇
  1990年   92篇
  1989年   93篇
  1988年   92篇
  1987年   86篇
  1986年   91篇
  1985年   87篇
  1984年   53篇
  1983年   54篇
  1982年   30篇
  1979年   31篇
  1978年   25篇
  1977年   35篇
  1976年   24篇
  1974年   23篇
  1973年   23篇
  1972年   34篇
  1971年   25篇
排序方式: 共有5946条查询结果,搜索用时 31 毫秒
91.
92.
Radiation safety management condition in Japanese nuclear medicine facilities were investigated by the questionnaire method. The first questionnaire was asked in all Japanese 1,401 Nuclear Medicine facilities. Answers from 624 institutes (44.5%) were received and analyzed. The radiation-safety management in nuclear medicine institutes was considered to be very well performed everyday. Opinion for the present legal control of nuclear medicine institutes was that the regulation in Japan was too strict for the clinical use of radionuclides. The current regulation is based on the assumption that 1% of all radioactivity used in nuclear medicine institutes contaminates into the draining-water system. The second questionnaire detailing the contamination of radioactivity in the draining-water system was sent to 128 institutes, and 64 answers were received. Of them, 42 institutes were considered to be enough to evaluate the contamination of radioactivity in the draining-water system. There was no difference between 624 institutes answered to the first questionnaire and 42 institutes, where the radioactivity in the draining-water system was measured, in the distribution of the institute size, draining-water system equipment and the radioactivity measuring method, and these 42 institutes seemed to be representative of Japanese nuclear medicine institutes. Contamination rate of radioactivity into the draining system was calculated by the value of radioactivity in the collecting tank divided by the amount of radionuclides used daily in each institute. The institutes were divided into two categories on the basis of nuclear medicine practice pattern; type A: in-vivo use only and type B: both in-vivo and in-vitro use. The contamination rate in 27 type A institutes did not exceed 0.01%, whereas in 15 type B institutes the contamination rate distributed widely from undetectable to above 1%. These results indicated that the present regulation for the draining-water system, which assumed that 1% of all radioactivity used in nuclear medicine institutes contaminated into draining-water system, should be reconsidered in nuclear medicine facilities where radionuclides are used only in in-vivo studies.  相似文献   
93.
The incidence, distribution, time of appearance, and radiologic findings of bone metastases from soft tissue sarcomas, exclusive of lymphomas, were evaluated in 320 patients with soft tissue sarcomas. Thirty patients (9.4%) had evidence of 58 bone metastases. Five of 30 patients presented with metastases, and 25 of 30 patients developed metastases up to 66 months after presentation with a mean time interval of 21.3 months. The incidence of skeletal metastases differed among histologic subtypes of sarcomas; alveolar soft part sarcoma (5 of 8), dedifferentiated liposarcoma (2 of 4), angiosarcoma (2 of 4), and rhabdomyosarcoma (5 of 16) tended to show a higher incidence of bone metastases. The sarcomas metastasized to the regional bones close to the primary tumor in 16 (53%) of 30 patients and to the axial bones in 18 (60%). On conventional radiographs, the osseous metastases demonstrated predominantly osteolytic changes, and evidence of pathological fracture was observed in 31% of 58 metastases.  相似文献   
94.
A 63-year-old man was referred to our department for treatment of intermittent claudication in the right lower limb. The preoperative angiogram showed severe stenosis extending from the terminal aorta to the bilateral common femoral arteries, with occlusion of the right superficial femoral artery and the left popliteal artery. He underwent aortobifemoral bypass with thromboendarterectomy of the left common femoral artery, and right graft-popliteal artery bypass. The patient had an uneventful postoperative course; however, 14 days after the operation, a pulsatile mass suddenly appeared in the left groin. Emergency surgery revealed disruption of the left distal anastomosis of the aortobifemoral bypass and therefore, revision, in the form of graft-profunda femoris artery interposition with graft-superficial femoral artery bypass, was performed. Microscopic examination showed colonies of bacteria in the host artery adventitia adjacent to the anastomosis. Culture of the discharge from the right groin operative scar revealed methicillin-resistantStaphylococcus aureus (MRSA). The discharge resolved following the intravenous administration of vancomycin and the local application of vancomycin ointment. There were no operative complications other than the MRSA infection, and the patient was discharged 20 days after revision surgery. In the 14 months since the revision, all grafts have remained patent and there have been no further symptoms of graft infection.  相似文献   
95.
Whether primary sclerosing cholangitis (PSC) occurs after orthotopic liver transplantation is controversial, largely because the pre-transplant diagnosis of PSC is based on nonspecific radiological and histological findings. We reviewed clinical, radiological, and histological records of 53 patients who underwent liver transplantation for PSC between 1985 and 1998. Three patients with patent hepatic arteries and no evidence of chronic rejection had radiological and histological findings that may have been due to recurrent PSC. Bile duct stricturing in these patients proved permanent and progressive and affected both the quality of life and graft survival. The first patient, who is 110 months after transplantation, has had repeated episodes of cholangitis for the last year. The second patient underwent excision of a strictured hepatic duct 45 months after transplantation and was ultimately retransplanted 95 months after initial transplantation. The third patient underwent left hemihepatectomy of an atrophied lobe 50 months after transplantation. Although the patient population assessed in this study is limited, putative recurrent PSC in the allografts has led either to graft loss or to clinically significant hepatobiliary complications of the graft. Received for publication on March 8, 1999; accepted on April 30, 1999  相似文献   
96.
This article describes the measurement of the frontal and prefrontal lobe volumes on three dimensional (3-D) MRI in 13 children aged 5 months to 14 years and in 3 adults aged 27 to 39 years. The 3-D MRI data were acquired by the fast spoiled gradient recalled (SPGR) sequence using a 1.5 T MR imager. The frontal and prefrontal lobe volumes were measured by the volume measurement function of the Workstation. We confirmed that this technique to analyze segmental brain volumes achieved acceptable levels of reliability and accuracy. There was an increase in the frontal and prefrontal lobe volumes with advancing age, being rapid between 8 and 15 years of age. The prefrontal to frontal lobe volume ratio also increased gradually, with spurts between 8 and 15 years of age. This approach may be particularly useful for studies on patients with frontal and prefrontal lobe dysfunctions.  相似文献   
97.
98.
99.
Indocyanine green iris angiography of lung carcinoma metastatic to the iris   总被引:1,自引:0,他引:1  
· Background: To investigate the usefulness of indocyanine green (ICG) iris angiography for monitoring vascular abnormalities and the clinical course of metastatic iris tumor during chemotherapy. · Methods: We performed ICG iris angiography at several points during systemic chemotherapy for a 67-year-old man who had been diagnosed as having small-cell carcinoma of the lung with metastatic iris tumors. · Results: ICG iris angiography clearly demonstrated hyperfluorescent tumor vessels, rubeosis iridis, and dilated iris stromal vessels. After chemotherapy, these hyperfluorescent vessels and rubeosis regressed. · Conclusion: ICG iris angiography appears to be an effective and useful method for observing abnormal vessels associated with metastatic iris tumors. Received: 11 May 1998 Revised version received: 30 July 1998 Accepted: 13 August 1998  相似文献   
100.
Pharmacokinetic and clinical evaluations of meropenem (SM-7338, MEPM) were carried out in pediatric patients. The following results were obtained. 1. After 30-minute intravenous drip infusion at a dose of 20 mg/kg, plasma concentrations of MEPM reached their peaks at the end of drip infusion with an average value of 48.8 +/- 3.64 micrograms/ml, and the average plasma half-life was 0.93 +/- 0.21 hour in the beta-phase. After 30-minute intravenous drip infusion at a dose of 10 mg/kg, the average peak plasma concentration was 27.7 +/- 4.33 micrograms/ml and the average plasma half-life was 0.78 +/- 0.20 hour. 2. Urinary excretion rates of MEPM after 30-minute intravenous drip infusion at doses of 20 and 10 mg/kg were 44.8 +/- 4.54% and 40.9 +/- 1.78%, respectively. 3. MEPM was administered to 13 cases (upper and lower respiratory infections, pneumonia and lymphadenitis) at daily doses between 60-90 mg/kg/day divided into 3 dosages using 30-minute intravenous drip infusion. Clinical responses were "excellent" in 12 patients, "good" in 1, hence an efficacy rate of 100% was obtained. 4. Bacteria identified in various disease cases included 12 strains of 5 species, and the eradication rate was 100%. 5. No side effects were observed in any children. Laboratory test results showed abnormalities in 2 cases with elevations of GOT and GPT. These results suggest that MEPM may be a very useful and safe drug for the treatment of pediatric infections.  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