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   117570篇
  免费   8676篇
  国内免费   337篇
耳鼻咽喉   1719篇
儿科学   3249篇
妇产科学   2632篇
基础医学   14616篇
口腔科学   2694篇
临床医学   12720篇
内科学   22851篇
皮肤病学   1701篇
神经病学   10618篇
特种医学   4507篇
外国民族医学   6篇
外科学   18382篇
综合类   1705篇
一般理论   117篇
预防医学   11105篇
眼科学   2459篇
药学   8013篇
  2篇
中国医学   167篇
肿瘤学   7320篇
  2022年   911篇
  2021年   2397篇
  2020年   1270篇
  2019年   2168篇
  2018年   2526篇
  2017年   1909篇
  2016年   1917篇
  2015年   2146篇
  2014年   3183篇
  2013年   4626篇
  2012年   6921篇
  2011年   7169篇
  2010年   3906篇
  2009年   3399篇
  2008年   6262篇
  2007年   6648篇
  2006年   6513篇
  2005年   6488篇
  2004年   6061篇
  2003年   5583篇
  2002年   5314篇
  2001年   2147篇
  2000年   2187篇
  1999年   2064篇
  1998年   1352篇
  1997年   1150篇
  1996年   1086篇
  1995年   1023篇
  1994年   935篇
  1993年   860篇
  1992年   1630篇
  1991年   1536篇
  1990年   1452篇
  1989年   1351篇
  1988年   1269篇
  1987年   1255篇
  1986年   1185篇
  1985年   1274篇
  1984年   1149篇
  1983年   989篇
  1982年   971篇
  1981年   877篇
  1980年   851篇
  1979年   865篇
  1978年   798篇
  1977年   677篇
  1976年   607篇
  1975年   594篇
  1974年   634篇
  1973年   621篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
PURPOSE: Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, increases survival when combined with irinotecan-based chemotherapy in first-line treatment of metastatic colorectal cancer (CRC). This randomized, phase II trial compared bevacizumab plus fluorouracil and leucovorin (FU/LV) versus placebo plus FU/LV as first-line therapy in patients considered nonoptimal candidates for first-line irinotecan. PATIENTS AND METHODS: Patients had metastatic CRC and one of the following characteristics: age > or = 65 years, Eastern Cooperative Oncology Group performance status 1 or 2, serum albumin < or = 3.5 g/dL, or prior abdominal/pelvic radiotherapy. Patients were randomly assigned to FU/LV/placebo (n = 105) or FU/LV/bevacizumab (n = 104). The primary end point was overall survival. Secondary end points were progression-free survival, response rate, response duration, and quality of life. Safety was also assessed. RESULTS: Median survival was 16.6 months for the FU/LV/bevacizumab group and 12.9 months for the FU/LV/placebo group (hazard ratio, 0.79; P = .16). Median progression-free survival was 9.2 months (FU/LV/bevacizumab) and 5.5 months (FU/LV/placebo); hazard ratio was 0.50; P = .0002. Response rates were 26.0% (FU/LV/bevacizumab) and 15.2% (FU/LV/placebo) (P = .055); duration of response was 9.2 months (FU/LV/bevacizumab) and 6.8 months (FU/LV/placebo); hazard ratio was 0.42; P = .088. Grade 3 hypertension was more common with bevacizumab treatment (16% v 3%) but was controlled with oral medication and did not cause study drug discontinuation. CONCLUSION: Addition of bevacizumab to FU/LV as first-line therapy in CRC patients who were not considered optimal candidates for first-line irinotecan treatment provided clinically significant patient benefit, including statistically significant improvement in progression-free survival.  相似文献   
32.
Anemia has been associated with a poorer treatment response and reduced survival in women undergoing primary radiotherapy (RT) or radiochemotherapy for advanced cervical carcinoma. This study aimed to determine the influence of anemia on outcome in patients with cervical carcinoma undergoing adjuvant RT. Medical records were reviewed for 183 cervical cancer patients who had received adjuvant RT because of risk factors after radical surgery (n= 109) or inadequate primary surgery (simple hysterectomy; n= 74). Kaplan-Meier and Cox regression analyses were used to study hemoglobin levels before and during adjuvant RT in relation to recurrence-free and overall survival. Hemoglobin values > or =11 g/dL were considered normal, while those <11 g/dL indicated anemia. Hemoglobin levels before RT influenced significantly overall survival and recurrence-free survival across the whole group (overall survival--log rank(all patients)= 7.5; df = 1; P= 0.006). However, subgroup analysis showed that the observed difference was mainly due to the group of women who had undergone inadequate primary surgery (overall survival--log rank(inadequate surgery)= 10.8; df = 1; P= 0.001). Multifactorial regression analyses comparing hemoglobin before RT with grading and tumor stage confirmed the prognostic value of hemoglobin values. Maintaining normal hemoglobin values before and during adjuvant RT seems to be important, especially in patients who have had inappropriate simple hysterectomy, which may resemble a therapeutic situation.  相似文献   
33.
34.
BackgroundHuman studies on exercise, cognition, and apolipoprotein E (APOE) genotype show that ε4 carriers may benefit from regular physical activity.MethodsWe examined voluntary wheel-running, memory, and hippocampal plasticity in APOE ε3 and APOE ε4 transgenic mice at 10–12 months of age.ResultsSedentary ε4 mice exhibited deficits in cognition on the radial-arm water maze (RAWM), a task dependent on the hippocampus. Six weeks of wheel-running in ε4 mice resulted in improvements on the RAWM to the level of ε3 mice. Hippocampal brain-derived neurotrophic factor (BDNF) levels were similar in ε3 and ε4 mice, and after exercise BDNF was similarly increased in both ε3 and ε4 mice. In sedentary ε4 mice, tyrosine kinase B (Trk B) receptors were reduced by 50%. Exercise restored Trk B in ε4 mice to the level of ε3 mice, and in ε4 mice, exercise dramatically increased synaptophysin, a marker of synaptic function.ConclusionsOur results support the hypothesis that exercise can improve cognitive function, particularly in ε4 carriers.  相似文献   
35.
36.
37.
38.
39.
40.
A 37-year-old male with history of alcohol abuse presented to us with nausea, vomiting, and abdominal pain with ascites. He was diagnosed with alcoholic liver disease with coagulopathy and pancreatitis. During hospitalization, the patient developed intra-abdominal hemorrhage. He was treated with platelets, packed red blood cells and fresh frozen plasma without any improvement. Following this he was treated with activated recombinant factor VII (90 microg/kg), which resulted in normalization of the prothrombin time and the activated partial thromboplastin time and stabilization of hematocrit within a few hours. We review the current literature on the approved and off-label use of activated recombinant factor VII.  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