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   9261篇
  免费   885篇
  国内免费   12篇
耳鼻咽喉   71篇
儿科学   269篇
妇产科学   155篇
基础医学   1308篇
口腔科学   201篇
临床医学   1130篇
内科学   1915篇
皮肤病学   105篇
神经病学   730篇
特种医学   284篇
外科学   1510篇
综合类   195篇
一般理论   11篇
预防医学   988篇
眼科学   111篇
药学   587篇
肿瘤学   588篇
  2022年   111篇
  2021年   194篇
  2020年   131篇
  2019年   185篇
  2018年   209篇
  2017年   132篇
  2016年   121篇
  2015年   160篇
  2014年   204篇
  2013年   327篇
  2012年   464篇
  2011年   456篇
  2010年   226篇
  2009年   227篇
  2008年   412篇
  2007年   421篇
  2006年   441篇
  2005年   399篇
  2004年   384篇
  2003年   338篇
  2002年   379篇
  2001年   291篇
  2000年   275篇
  1999年   226篇
  1998年   106篇
  1997年   86篇
  1996年   77篇
  1995年   79篇
  1994年   65篇
  1993年   89篇
  1992年   195篇
  1991年   174篇
  1990年   204篇
  1989年   165篇
  1988年   153篇
  1987年   149篇
  1986年   142篇
  1985年   147篇
  1984年   121篇
  1983年   85篇
  1981年   62篇
  1979年   115篇
  1978年   82篇
  1976年   72篇
  1975年   73篇
  1974年   86篇
  1973年   82篇
  1972年   87篇
  1970年   66篇
  1969年   81篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Cancer Chemotherapy and Pharmacology - Addition of solid doxorubicin or solutions to pre-formed liposomes proved to be the optimal method for incorporating the drug into liposomes whilst...  相似文献   
2.
3.
4.
Most publications citing the effectiveness of renal extracorporeal shock wave lithotripsy have used plain abdominal radiography to assess residual calculi after treatment. We compared radiologist sensitivity and specificity in the detection of calculi on plain abdominal radiographs versus conventional film-screen and digital renal tomograms in extracorporeal shock wave lithotripsy patients. Of the patients 50 were imaged before and within 24 hours after lithotripsy. Six radiologists evaluated the resultant 300 studies for the presence and location of calculi. The mean sensitivity for digital tomograms was 83% for pre-lithotripsy and post-lithotripsy studies, which was significantly higher than for plain abdominal radiography and conventional tomography after lithotripsy. However, there were significantly more false positive stone diagnoses associated with digital tomogram interpretation. Signal detection analysis verified the over-all superiority of digital tomography for post-extracorporeal shock wave lithotripsy imaging. Calculus detection by conventional and digital tomography is superior to detection by plain abdominal radiography. However, because we did not perform delayed imaging, it is not possible to say what impact digital tomography might have on the management of extracorporeal shock wave lithotripsy patients.  相似文献   
5.
To determine effect of interaction between dietary cholesterol and triglyceride, i.e., polyunsaturated to saturated (P:S) fatty acid ratio, on LDL metabolism, male cynomolgus macaques were fed purified diets for 83 wk with cholesterol levels of 0.01, 0.06 and 0.50 mg/kJ and P:S ratios of 0.5 and 0.9, oleic acid constant. There were six groups of five animals each (cholesterol, mg/kJ--P:S ratio): Group 1, 0.01--0.5; Group 2, 0.01--0.9; Group 3, 0.06--0.5; Group 4, 0.06--0.9; Group 5, 0.50-0.5; Group 6, 0.50-0.9. LDL (1.019 less than d less than 1.063 kg/L) and glucosylated LDL were iodinated for turnover studies. Hepatic LDL transport was determined using 125I-tyramine-cellobiose-LDL as tracer. Plasma cholesterol increased in proportion to dietary cholesterol, and concentrations (mmol/L) at 77-78 wk were (mean +/- SEM): Group 1, 434 +/- 0.31; Group 2, 3.03 +/- 0.14; Group 3, 8.28 +/- 1.48; Group 4, 7.34 +/- 1.31; Group 5, 15.54 +/- 1.44; Group 6, 15.54 +/- 1.41. LDL cholesterol was 45% higher in Group 1 (2.43 mmol/L) than in Group 2 (1.68 mmol/L). In vivo studies showed that LDL clearance was suppressed by excess dietary cholesterol; receptor-independent LDL clearance was relatively constant. Hepatic LDL protein transport was greater in Group 2 (P:S 0.9) compared with Group 1 (P:S 0.5). The LDL protein synthetic rate was lower in Groups 2, 4 and 6 (P:S 0.9) relative to Groups 1, 3 and 5 (P:S 0.5). We conclude that in this model hepatic LDL receptor activity is altered by degree of saturation in dietary triglycerides when dietary cholesterol is minimal, and that saturated dietary triglycerides enhance LDL protein secretion when dietary cholesterol is ample.  相似文献   
6.
7.
8.
9.
Mean subcutaneous tissue PO2 (PsqO2) measurements were obtained in dogs with an unheated electrode placed in an implanted Silastic tonometer, while PaO2 was increased in increments from 40 to 600 torr during normal, increased, and reduced blood volume. These changes reflect that the mean PsqO2 is approximately 10 torr below the PO2 of venous blood draining that tissue. Since PaO2 was already known, the oxygen content of arterial and venous blood entering and leaving this tissue could be determined by reference to blood-oxygen dissociation curves. Therefore, relative changes in blood flow could be calculated using the Fick principle. After a 20% blood loss, the PsqO2 measured during breathing of room air fell to 20% of baseline, corresponding to an 80% fall in sc blood flow; it remained low until the shed blood was returned despite compensatory changes in cardiac output. Rapid infusion of electrolyte solutions in normovolemic animals produced a temporary increase in local blood flow. Subcutaneous oximetry seems capable of quantifying peripheral perfusion and may be clinically useful.  相似文献   
10.
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