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   13829篇
  免费   1228篇
  国内免费   23篇
耳鼻咽喉   205篇
儿科学   428篇
妇产科学   500篇
基础医学   1780篇
口腔科学   190篇
临床医学   1425篇
内科学   2628篇
皮肤病学   208篇
神经病学   1668篇
特种医学   342篇
外科学   1484篇
综合类   347篇
一般理论   14篇
预防医学   1503篇
眼科学   168篇
药学   1179篇
中国医学   21篇
肿瘤学   990篇
  2023年   79篇
  2022年   116篇
  2021年   307篇
  2020年   195篇
  2019年   293篇
  2018年   320篇
  2017年   244篇
  2016年   283篇
  2015年   298篇
  2014年   443篇
  2013年   566篇
  2012年   859篇
  2011年   882篇
  2010年   447篇
  2009年   366篇
  2008年   666篇
  2007年   663篇
  2006年   617篇
  2005年   580篇
  2004年   545篇
  2003年   497篇
  2002年   501篇
  2001年   385篇
  2000年   404篇
  1999年   349篇
  1998年   133篇
  1997年   129篇
  1996年   120篇
  1995年   106篇
  1994年   99篇
  1993年   89篇
  1992年   221篇
  1991年   242篇
  1990年   271篇
  1989年   219篇
  1988年   191篇
  1987年   208篇
  1986年   182篇
  1985年   212篇
  1984年   154篇
  1983年   108篇
  1982年   75篇
  1981年   73篇
  1979年   111篇
  1978年   101篇
  1975年   74篇
  1974年   103篇
  1973年   89篇
  1972年   86篇
  1971年   71篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
41.
42.
Background : A patient with a solitary pulmonary metastasis who had breast cancer in the past may benefit from pulmonary resection. Methods : Between 1984 and 1996, 17 patients underwent metastatectomy for metastatic breast cancer. There were 15 females and two males whose average age was 59 (range: 40–74 years). The median tumour-free interval after the primary breast-cancer operation was 5.1 years (range: 8 months-18.2 years). Sixteen patients had complete resections, which included six lobectomies and 10 lesser resections. Results : The postoperative mortality was nil and the morbidity rate was 6%. Follow-up was complete in all patients. Recurrent disease developed in four patients and two patients died of their disease. The 5-year survival was 62%. Conclusion : An aggressive surgical approach is warranted in patients with isolated resectable pulmonary metastases from breast cancer.  相似文献   
43.
During an exposure monitoring study, 78 saw maintenance tradesmen were randomly assigned to be interviewed about their exposures using one of two questionnaire formats: open-ended and partly prompted questions about five categories of materials; and detailed prompting about 75 agents. The more open-ended questionnaire elicited fewer exposure responses overall, but more responses about agents not included on the detailed questionnaire. Composite materials and trade name products were more frequently cited as exposures than individual metals or compounds. Validity of responses was ascertained using air measurements (individual metals) or observations of the employees (composite materials). Sums of sensitivities and specificities were very low (near 1.0) for most of the metals for both types of questionnaire. For composite materials, validity improved substantially. Sensitivities with the partly prompted format (0.44–0.85) were always lower than with detailed prompting (0.80–1.00). Specificities were usually, but not always, higher with partial prompting (0.66–0.92) than with detailed prompting (0.18–0.86). Selection of questionnaire format for an epidemiologic study would depend on the likely prevalence of exposure in controls and the effects of trade-offs in sensitivity and specificity.  相似文献   
44.
Avasimibe is a novel orally bioavailable ACAT inhibitor, currently under clinical development (phase III trials). It was safe when administered to rats, dogs, and humans. In vitro studies in human macrophages demonstrated that avasimibe reduces foam cell formation not only by enhancing free cholesterol efflux, but also by inhibiting the uptake of modified LDL. The concentration‐dependent reduction in cellular cholesteryl ester content in these cells was not accompanied by an increase in intracellular free cholesterol, which is in agreement with a good safety profile for avasimibe. In the liver, avasimibe caused a significant reduction in the secretion of apo B and apo B‐containing lipoproteins into plasma. Avasimibe induced cholesterol 7α‐hydroxylase and increased bile acid synthesis in cultured rat hepatocytes, and its administration to rats did not produce an increase in lithogenicity index of the bile. The hypolipidemic efficacy of the compound was demonstrated in cholesterol‐fed as well as in non‐cholesterol‐fed animals. In these models, plasma cholesterol levels were reduced, mainly due to the decrease in the non‐HDL cholesterol fraction. Clinical data are scarce, but in a study performed in 130 men and women with combined hyperlipidemia and hypoalphalipoproteinemia, avasimibe, 50–500 mg/day, significantly reduced plasma total triglyceride and VLDL‐cholesterol. Although total cholesterol, LDL‐cholesterol, and HDL‐cholesterol were unchanged, it must be stressed that animal data suggest that avasimibe may have direct antiatherosclerotic activity in addition to its cholesterol‐lowering effect. Avasimibe treatment can also contribute to increase plaque stability, as it reduces the accumulation of lipids in the arterial wall, inhibits macrophage infiltration into the media and reduces matrix metalloproteinase expression and activity. Moreover, avasimibe and statins have been shown to have synergistic effects, and the combination therapy may not only inhibit atherosclerotic lesion progression but also induce lesion regression, independently of changes in plasma cholesterol.  相似文献   
45.
46.
Holter technology has endured for more than 40 years, and proven to be a valuable adjunctive noninvasive diagnostic technology to record the ambulatory or long‐term electrocardiogram in the study of living creatures. During this span of time, many scientists, physicians, and innovators contributed to the development and evolution of Holter technology. This essay seeks to document a view of the history and evolution of the technology during that time, and concomitantly give recognition to the scientists, physicians, and engineers who contributed so greatly.  相似文献   
47.
48.
Plasma levels of cannabidiol (CBD) were ascertained weekly in 14 Huntington's disease patients undergoing a double-blind, placebo-controlled, crossover trial of oral CBD (10 mg/kg/day = about 700 mg/day) for 6 weeks. The assay procedure involved trimethylsilyl (TMS) derivatization of CBD and the internal standard delta-6-tetrahydrocannabinol (THC), capillary column gas chromatography, ion trap mass spectroscopy in positive ion chemical ionization mode using isobutane, and calculations of CBD levels based on peak ion intensity of the 387 M + H peak of delta-6-THC-TMS and the 459 M + H peak of CBD-2TMS. The sensitivity of the assay was about 500 pg/ml, and the precision was about 10-15%. Mean plasma levels of CBD ranged from 5.9-11.2 ng/ml over the 6 weeks of CBD administration. CBD levels averaged 1.5 ng/ml one week after CBD was discontinued, and were virtually undetectable thereafter. The elimination half-life of CBD was estimated to be about 2-5 days, and there were no differences between genders for half-life or CBD levels. Additionally, no plasma delta-1-THC, the major psychoactive cannabinoid of marijuana, was detected in any subject.  相似文献   
49.
T Khansur  A Kennedy 《Cancer》1991,67(8):2030-2032
Seven patients with advanced locoregional or metastatic squamous cell carcinoma of the skin were treated with cis-daimminedichloroplatin (cisplatin) and 5-fluorouracil (5-FU). Responses were seen in six of seven patients (three partial responses [PR] and three complete responses [CR]). One patient is alive and disease-free at 2 years. These results indicate that cisplatin and 5-FU is an effective combination regimen that should be used in future clinical trials in squamous cell carcinoma of the skin.  相似文献   
50.
Encouraging hypertensive pregnant women to take their own blood pressure produces reliable and consistent results. It has proved popular among women, enabling them to assess the fluctuations of their blood pressure at first hand and to maintain a sense of control.  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