全文获取类型
收费全文 | 6996篇 |
免费 | 376篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 133篇 |
儿科学 | 397篇 |
妇产科学 | 155篇 |
基础医学 | 691篇 |
口腔科学 | 118篇 |
临床医学 | 409篇 |
内科学 | 1365篇 |
皮肤病学 | 134篇 |
神经病学 | 441篇 |
特种医学 | 597篇 |
外科学 | 976篇 |
综合类 | 314篇 |
预防医学 | 346篇 |
眼科学 | 276篇 |
药学 | 462篇 |
1篇 | |
中国医学 | 18篇 |
肿瘤学 | 549篇 |
出版年
2022年 | 72篇 |
2021年 | 136篇 |
2020年 | 80篇 |
2019年 | 111篇 |
2018年 | 133篇 |
2017年 | 104篇 |
2016年 | 142篇 |
2015年 | 121篇 |
2014年 | 219篇 |
2013年 | 277篇 |
2012年 | 347篇 |
2011年 | 415篇 |
2010年 | 262篇 |
2009年 | 260篇 |
2008年 | 313篇 |
2007年 | 372篇 |
2006年 | 351篇 |
2005年 | 278篇 |
2004年 | 279篇 |
2003年 | 243篇 |
2002年 | 181篇 |
2001年 | 152篇 |
2000年 | 165篇 |
1999年 | 152篇 |
1998年 | 125篇 |
1997年 | 123篇 |
1996年 | 125篇 |
1995年 | 97篇 |
1994年 | 60篇 |
1993年 | 86篇 |
1992年 | 66篇 |
1991年 | 60篇 |
1990年 | 70篇 |
1989年 | 106篇 |
1988年 | 85篇 |
1987年 | 107篇 |
1986年 | 100篇 |
1985年 | 123篇 |
1984年 | 87篇 |
1983年 | 62篇 |
1982年 | 43篇 |
1981年 | 53篇 |
1980年 | 50篇 |
1978年 | 47篇 |
1977年 | 53篇 |
1976年 | 42篇 |
1975年 | 43篇 |
1973年 | 49篇 |
1972年 | 42篇 |
1971年 | 37篇 |
排序方式: 共有7382条查询结果,搜索用时 15 毫秒
11.
Maxillary sinusitis in adults: an evaluation of placebo-controlled double-blind trials 总被引:1,自引:0,他引:1
BACKGROUND: In general practice, acute sinusitis is frequently diagnosed
and treated with antibiotics. OBJECTIVE: This study aimed to determine the
evidence for the effectiveness of antibiotic treatment in acute maxillary
sinusitis in adults by assessing the methodological quality of
placebo-controlled double-blind randomized trials. METHOD: An evaluation by
four raters through a 35-item scoring-scale for internal and external
validity of all placebo-controlled double-blind randomized trials on acute
sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five
trials were excluded because they were not placebo-controlled,
double-blind, randomized, or were carried out in patients with chronic
sinusitis or in children. The three remaining trials were performed in
different populations (one in general practice) between 1973 and 1978. Only
one study claimed superiority of antibiotic treatment. Different inclusion
criteria and major outcome measures were used by the authors. The
reliability of major outcome events was reported poorly or not at all and
in two studies outcome measures were clinically inappropriate. The studies
scored 30-62% of the maximum attainable score for internal validity and
10-20% for external validity. CONCLUSION: The effectiveness of antibiotic
treatment in acute maxillary sinusitis in a general practice population is
not based sufficiently on evidence.
相似文献
12.
13.
M. Barua R. Sinha A. Majumdar 《Indian journal of otolaryngology and head and neck surgery》1993,45(2):87-90
Between 1986–1990, 290 patients with squamouscell carcinoma of the hypopharynx were assessed at the S. S. K. M. Hospital Calcutta,
out of the total of 1460 number of Head Neck cancer, (19.8%). The most frequent initial symptom was a foreign body sensation
in the throat (70%), and males were affected more than females (9.8 : 1.2). The peak age incidence was found between 40 and
50 years (24%). Most of the patients came in advanced stages with cervical lymph node metastases (60%).
One interesting fact that came out from the present study is the Right pyriform fassa was more commonly affected than the
left in righthanded persons (56.9%). Though the reason is not clear it could be due to right — sided swallow, as one side
may be predominant in funtion. 相似文献
14.
15.
16.
17.
BACKGROUND: There are obvious advantages to increasing donor retention. However, for reasons of blood safety, certain donors may, in fact, be more desirable to retain than others. “Safe” donors are defined as those who provided a blood donation that was negative on all laboratory screening tests and who subsequently reported no behavioral risks in response to an anonymous survey. This study identifies the most important factors affecting the intention of “safe” donors to provide another donation. STUDY DESIGN AND METHODS: An anonymous survey asking about donation history, sexual history, injecting drug use, and recent donation experience was mailed to 50,162 randomly selected allogeneic donors (including directed donors) who gave blood from April through July or from October through December 1993 at one of the five United States blood centers participating in the Retrovirus Epidemiology Donor Study. Before mailing, questionnaires were coded to designate donors with nonreactive laboratory screening tests at their most recent donation. RESULTS: A total of 34,726 donors (69%) responded, with substantially higher response among repeat donors. According to reported intentions only, the vast majority of “safe” donors indicated a high likelihood of donating again within the next 12 months. Only 3.4 percent reported a low likelihood of donating again. A comparison of those likely to return and those unlikely to return reveals significant differences in demographics and in ratings of the donation experience. A higher proportion of those unlikely to return were first-time donors, minority-group donors, and donors with less education. The highest projected loss among “safe” donors was seen for those who gave a fair to poor assessment of their treatment by blood center staff or of their physical well-being during or after donating. CONCLUSION: These data suggest that efforts to improve donors' perceptions of their donation experience, as well as attention to the physical effects of blood donation, may aid in the retention of both repeat and first-time donors. 相似文献
18.
David S. K. Lu Shantanu Sinha John Lucas Keyvan Farahani Robert Lufkin Klaus Lewin 《Journal of magnetic resonance imaging : JMRI》1997,7(2):303-308
The purpose of this study was to test the feasibility of MR-guided percutaneous ethanol ablation of liver tissue on a .2-T open MR scanner. Needles were placed by MR guidance first into an ex vivo sheep liver and then into livers of three anesthetized pigs, and injection of 10 ml of 96% alcohol was performed. T1 fast low-angle shot (FLASH), T2 turbo spin echo (TSE), and T1 spin echo (SE) images were obtained after incremental volumes of injection. In one pig, simultaneous injection of saline into normal liver was also performed with subsequent pathological correlation. Ethanol-infiltrated liver was hypointense to liver on all sequences, whereas saline caused no tissue signal changes on T1 SE and either isointense or hyperintense changes on T2 TSE images. Pathological examination confirmed ethanol-induced acute liver changes as compared with the control. MR guidance of needle placement and monitoring of ethanol effects on liver tissue is feasible. This may have implications for potential MR-guided hepatic tumor ablation. 相似文献
19.
20.