全文获取类型
收费全文 | 36068篇 |
免费 | 2025篇 |
国内免费 | 106篇 |
专业分类
耳鼻咽喉 | 438篇 |
儿科学 | 2137篇 |
妇产科学 | 705篇 |
基础医学 | 4629篇 |
口腔科学 | 813篇 |
临床医学 | 2534篇 |
内科学 | 7355篇 |
皮肤病学 | 843篇 |
神经病学 | 1906篇 |
特种医学 | 808篇 |
外科学 | 5003篇 |
综合类 | 1327篇 |
一般理论 | 15篇 |
预防医学 | 2122篇 |
眼科学 | 1545篇 |
药学 | 3518篇 |
中国医学 | 275篇 |
肿瘤学 | 2226篇 |
出版年
2023年 | 238篇 |
2022年 | 673篇 |
2021年 | 1183篇 |
2020年 | 638篇 |
2019年 | 868篇 |
2018年 | 1057篇 |
2017年 | 724篇 |
2016年 | 969篇 |
2015年 | 1003篇 |
2014年 | 1358篇 |
2013年 | 1769篇 |
2012年 | 2427篇 |
2011年 | 2458篇 |
2010年 | 1389篇 |
2009年 | 1251篇 |
2008年 | 1796篇 |
2007年 | 1751篇 |
2006年 | 1768篇 |
2005年 | 1386篇 |
2004年 | 1393篇 |
2003年 | 1175篇 |
2002年 | 1004篇 |
2001年 | 822篇 |
2000年 | 867篇 |
1999年 | 730篇 |
1998年 | 309篇 |
1997年 | 213篇 |
1996年 | 222篇 |
1995年 | 217篇 |
1994年 | 177篇 |
1993年 | 151篇 |
1992年 | 498篇 |
1991年 | 406篇 |
1990年 | 430篇 |
1989年 | 395篇 |
1988年 | 357篇 |
1987年 | 356篇 |
1986年 | 351篇 |
1985年 | 323篇 |
1984年 | 262篇 |
1983年 | 219篇 |
1979年 | 230篇 |
1978年 | 148篇 |
1977年 | 180篇 |
1976年 | 139篇 |
1975年 | 171篇 |
1974年 | 182篇 |
1973年 | 182篇 |
1972年 | 173篇 |
1971年 | 161篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Exposure to air pollution affects pulmonary functions adversely. Effect of exposure to pollution on diurnal variation of peak flow was assessed in healthy students. Three hundred healthy age-matched nonsmoker students were studied. They were categorized into two groups on the basis of their residence: commuters and living on campus. Peak expiratory flow (PEF) recordings were made twice daily for 2 days with the Pink City Flow Meter. The measurement was then used to calculate for each subject the amplitude percentage mean, which is an index for expressing PEF variability for epidemiological purposes (Higgins BG, Britton JR, Chinns Jones TD, Jenkinson D, Burnery PG, Tattersfield AE. Distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989; 140:1368-1372). Air pollution parameters were quantified by measurement of sulfur dioxide (SO2), oxides of nitrogen (NO2), carbon monoxide (CO), and respirable suspended particulate matter (RSPM) in the ambient air at the campus and on the roadside. The mean values of PEF variability (amplitude percent mean) in the students living on campus and in the commuters were 5.7 +/- 3.2 and 11 +/- 3.6, respectively (P < .05). Among the commuters, maximum number of subjects showed amplitude percentage mean PEFR at the higher end of variability distribution, as compared to the students living on campus, among whom the majority of subjects fell in the lower ranges of variability distribution. The ambient air quality parameters, namely SO2, NO2, CO, and RSPM were significantly lower on the campus. It can be concluded that long-term periodic exposure to air pollution can lead to increased PEF variability even in healthy subjects. Measurement of PEF variability may prove to be a simple test to measure effect of air pollution in healthy subjects. 相似文献
82.
Steven N Singh X Charlene Tang Bramah N Singh Paul Dorian Domenic J Reda Crystal L Harris Ross D Fletcher Satish C Sharma J Edwin Atwood Alan K Jacobson H Daniel Lewis Becky Lopez Dennis W Raisch Michael D Ezekowitz 《Journal of the American College of Cardiology》2006,48(4):721-730
OBJECTIVES: The purpose of this study was to determine quality of life (QOL) and exercise performance (EP) in patients with persistent atrial fibrillation (AF) converted to sinus rhythm (SR) compared with those remaining in or reverting to AF. BACKGROUND: Restoration of SR in patients with AF improving QOL and EP remains controversial. METHODS: Patients with persistent AF were randomized double-blind to amiodarone, sotalol, or placebo. Those not achieving SR at day 28 were cardioverted and classified into SR or AF groups at 8 weeks (n = 624) and 1 year (n = 556). The QOL (SF-36), symptom checklist (SCL), specific activity scale (SAS), AF severity scale (AFSS), and EP were assessed. RESULTS: Favorable changes were seen in SR patients at 8 weeks in physical functioning (p < 0.001), physical role limitations (p = 0.03), general health (p = 0.002), and vitality (p < 0.001), and at 1 year in general health (p = 0.007) and social functioning (p = 0.02). Changes in the scores for SCL severity (p = 0.01), functional capacity (p = 0.003), and AFSS symptom burden (p < 0.001) at 8 weeks and in SCL severity (p < 0.01) and AF symptom burden (p < 0.001) at 1 year showed significant improvements in SR versus AF. Symptomatic patients were more likely to have improvement. The EP in SR versus AF was greater from baseline to 8 weeks (p = 0.01) and to 1 year (p = 0.02). The EP correlated with physical functioning and functional capacity except in the AF group at 1 year. CONCLUSIONS: In patients with persistent AF, restoration and maintenance of SR was associated with improvements in QOL measures and EP. There was a strong correlation between QOL measures and EP. 相似文献
83.
J.M. Smith D. Stablein A. Singh W. Harmon R.A. McDonald 《American journal of transplantation》2006,6(3):585-588
Graft thrombosis is the most common cause of first year graft failure in pediatric renal transplantation. The North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) database was analyzed for cases of graft failure due to thrombosis among patients transplanted from 1998 to 2004. The impact of interleukin-2 (IL-2) receptor antagonists as induction therapy was determined. There were a total of 51 graft failures due to thrombosis among the 2750 reported renal transplants (1.85%) (95% CI (1.39%, 2.41%)). This represents the most common cause of graft loss during the first year post-transplant accounting for 35% of first year losses and 18% of all graft losses. The incidence of thrombosis among patients who received IL-2 receptor antibodies was 1.07% (12/1126) compared to 2.40% (39/1624) among patients who did not (OR 0.44, 95% CI 0.23, 0.84, p = 0.014). Use of IL-2 receptor blockade was the only significant prognostic factor in a multivariate model with previously identified risk factors. Analysis of NAPRTCS data found that the use of IL-2 receptor antibodies as induction therapy is associated with a significantly decreased risk of graft failure due to thrombosis. This provocative finding requires further investigation to determine whether thrombotic failure can be decreased by this therapeutic strategy. 相似文献
84.
N Singh R Agarwal D Gupta M R Shivaprakash A Chakrabarti 《The European respiratory journal》2006,28(3):662-664
Phaeohyphomycosis is a disease caused by dematiaceous fungi. Here, the first culture-proven case of mediastinal mass due to Fonsecaea pedrosoi is reported. The patient was a 40-yr-old male who had presented with history of dyspnoea and dysphagia. Computed tomography of the chest disclosed a mediastinal mass. Cultures of a specimen from the mediastinum grew Fonsecaea pedrosoi. The patient received amphotericin B and itraconazole and showed a remarkable recovery. Repeat computed tomography revealed a reduction in the mediastinal mass. The case highlights the need for a high degree of clinical suspicion and appropriate histopathological and mycological examination of clinical specimens. 相似文献
85.
Case report Leptomeningeal involvement in diffuse intrinsic brain stem gliomas is rarely diagnosed clinically and in majority of the instances diagnosed only on postmortem examination. We report two cases of diffuse pontine glioma diagnosed clinicoradiologically and treated with conventional radiotherapy.Observations On follow-up, both patients showed clinical features suggestive of meningeal spread although imaging for pontine tumor showed stable disease. Leptomeningeal disease in the spine was confirmed on imaging and in one case by cerebrospinal fluid examination also. During the follow-up of patients with pontine glioma, the possibility of leptomeningeal involvement must be borne in mind. 相似文献
86.
87.
88.
S. C. Srivastava S. C. Gupta A. P. Singh 《Indian journal of otolaryngology and head and neck surgery》1993,45(4):188-190
In the present study 35 patients with preforated and 15 cases with intact ear drums, were studied and eustachian tube function
was assessed by Saccharine test. Bortnick-Miller test, and manual impedance audiometry. The merits and demerits of one over
the other were evaluated. It was observed thal more than one test when employed provides better information as every test
has its own advantages and limitations 相似文献
89.
Bengal gram seed coat appeared to be a potent hypocholesterolemic/hypolipidemic agent in rabbits. When fed to hypercholesterolemic rabbits, it lowered hepatic cholesterol/lipid much more than in the control group. Aortic lipid levels were rather marginally increased but the increase was less in Bengal gram seed coat fed rabbits. Though seed coat of Bengal gram failed to prevent the development of atherosclerosis in hypercholesterolemic rabbits, but certainly it slowed down the process of its development. The hypocholesterolemic action of Bengal gram seed coat appeared to be due to the increased catabolism and excretion of cholesterol. 相似文献
90.
Buprenorphine was introduced as a potent analgesic with low abuse potential. Reports of buprenorphine abuse by opiate abusers have accumulated over the years, highlighting its use as a cheap alternative to heroin. The lower potency compared with heroin is being compensated by using a cocktail of buprenorphine with benzodiazepines or cyclizine. This study of 18 cases seen over 3 years broadly confirms these findings. Four cases reported haematemesis during acute withdrawal, a symptom not reported in earlier studies. 相似文献