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   233736篇
  免费   5928篇
  国内免费   2066篇
耳鼻咽喉   1764篇
儿科学   7269篇
妇产科学   4138篇
基础医学   25486篇
口腔科学   3007篇
临床医学   17629篇
内科学   41895篇
皮肤病学   1697篇
神经病学   20461篇
特种医学   10816篇
外国民族医学   21篇
外科学   36728篇
综合类   7170篇
现状与发展   5篇
一般理论   5篇
预防医学   21347篇
眼科学   4156篇
药学   14858篇
  35篇
中国医学   1961篇
肿瘤学   21282篇
  2023年   370篇
  2022年   793篇
  2021年   1182篇
  2020年   833篇
  2019年   1046篇
  2018年   23340篇
  2017年   18490篇
  2016年   20663篇
  2015年   2384篇
  2014年   2677篇
  2013年   2898篇
  2012年   9730篇
  2011年   23684篇
  2010年   20447篇
  2009年   13060篇
  2008年   21575篇
  2007年   23867篇
  2006年   2557篇
  2005年   3884篇
  2004年   4697篇
  2003年   5638篇
  2002年   3690篇
  2001年   4889篇
  2000年   4937篇
  1999年   4059篇
  1998年   1566篇
  1997年   1195篇
  1996年   689篇
  1995年   598篇
  1994年   545篇
  1993年   469篇
  1992年   1964篇
  1991年   1755篇
  1990年   1648篇
  1989年   1561篇
  1988年   1347篇
  1987年   1228篇
  1986年   1084篇
  1985年   927篇
  1984年   607篇
  1983年   489篇
  1982年   275篇
  1981年   180篇
  1980年   180篇
  1979年   282篇
  1978年   85篇
  1974年   94篇
  1973年   96篇
  1970年   84篇
  1969年   86篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Five commercially available nitropolyclyclic aromatic hydrocarbons (nitro-PAH), namely, 4-nitrobiphenyl, 2-nitrofluorene, 9-nitroanthracene, 1-nitropyrene, and 2,7-dinitrofluorene, were exposed under restricted sunlight in the open air. The direct-acting mutagenicities of the samples after an exposure of 45 days were measured in order to compare them with those of the original samples in the Ames Salmonella typhimurium bioassay. It was found that the mutagenicities of some nitro-PAH do not change significantly while the mutagenicities of others increase or decrease after exposure. A preliminary study of nitro-PAH reaction products after exposure using GC, GC/MS, and FT-IR is also reported.  相似文献   
62.
63.
64.
In order to study the possible regressive changes of left ventricular hypertrophy in treated hypertensive patients and to correlate them either with the drugs they received and/or the blood pressure reduction obtained, a long-term (6 years) echocardiographic follow-up study was performed in 61 patients. B and M mode echocardiographic septum and posterior wall thickness and left ventricular mass index were measured yearly and the type of ventricular hypertrophy, asymmetric septal or concentric (symmetric), were compared before and after the follow-up. Sixteen patients received only diuretics; 14, only propranolol, and associated therapy was used in the remaining 31 patients. Average blood pressure was significantly reduced in the whole group of patients, but, individually, 30 of them achieved normal levels for the diastolic (90 mmHg), remaining it over this value in the other, although all of them experienced an average reduction 10 mmHg with therapy. Those patients with concentric hypertrophy at entry showed a significant septal, posterior wall thickness and total ventricular mass reduction during the follow-up, those with initial asymmetric septal hypertrophy, a significant septal thickness and ventricular mass reduction, and those without hypertrophy on admission, showed an average paradoxical increase in septal thickness. We conclude that left ventricular hypertrophy disappeared or decreased in 48% of the patients and that treatment seems to prevent its progression or development in the 43% of all patients. The regressive or favorable changes were significantly more frequent among patients with normal blood pressure after treatment as well as among patients treated only with propranolol in comparison to those treated only with diuretics.  相似文献   
65.
66.
67.
68.
69.
Single-agent chemotherapy of metastatic breast cancer is the treatment of choice in patients with slow tumor progression and asymptomatic disease. In this patient group, the choice of drugs is based more on good tolerability than on efficacy. By contrast, symptomatic or rapidly progressing disease requires the use of highly active regimens where more weight is put on reliable antitumor activity. While anthraycline-based combination regimens have set the standard of effective treatment, the addition of docetaxel (and to a lesser extent paclitaxel) has improved tumor response, but failed to induce a consistent prolongation of survival. Based on retrospective analyses, it is hypothesised that the combined use of anthracyclines and taxanes in first-line therapy may be most beneficial in defined subgroups: after adjuvant chemotherapy, in patients with HER-2 gene amplification, possibly also in patients with rapidly progressing visceral disease.  相似文献   
70.
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