全文获取类型
收费全文 | 233736篇 |
免费 | 5928篇 |
国内免费 | 2066篇 |
专业分类
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 |
出版年
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.
Volker Heinemann 《Breast cancer research and treatment》2003,81(1):43-48
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.