全文获取类型
收费全文 | 3382篇 |
免费 | 196篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 140篇 |
妇产科学 | 52篇 |
基础医学 | 474篇 |
口腔科学 | 56篇 |
临床医学 | 259篇 |
内科学 | 517篇 |
皮肤病学 | 126篇 |
神经病学 | 260篇 |
特种医学 | 145篇 |
外科学 | 437篇 |
综合类 | 371篇 |
预防医学 | 178篇 |
眼科学 | 84篇 |
药学 | 248篇 |
1篇 | |
中国医学 | 18篇 |
肿瘤学 | 194篇 |
出版年
2023年 | 15篇 |
2022年 | 27篇 |
2021年 | 83篇 |
2020年 | 35篇 |
2019年 | 67篇 |
2018年 | 84篇 |
2017年 | 49篇 |
2016年 | 71篇 |
2015年 | 91篇 |
2014年 | 96篇 |
2013年 | 128篇 |
2012年 | 177篇 |
2011年 | 206篇 |
2010年 | 175篇 |
2009年 | 109篇 |
2008年 | 159篇 |
2007年 | 160篇 |
2006年 | 161篇 |
2005年 | 116篇 |
2004年 | 137篇 |
2003年 | 92篇 |
2002年 | 98篇 |
2001年 | 83篇 |
2000年 | 99篇 |
1999年 | 88篇 |
1998年 | 48篇 |
1997年 | 40篇 |
1996年 | 41篇 |
1995年 | 36篇 |
1994年 | 36篇 |
1993年 | 16篇 |
1992年 | 46篇 |
1991年 | 39篇 |
1990年 | 45篇 |
1989年 | 50篇 |
1988年 | 38篇 |
1987年 | 45篇 |
1986年 | 44篇 |
1985年 | 42篇 |
1984年 | 34篇 |
1983年 | 28篇 |
1982年 | 24篇 |
1981年 | 21篇 |
1980年 | 27篇 |
1979年 | 30篇 |
1978年 | 20篇 |
1977年 | 22篇 |
1976年 | 16篇 |
1975年 | 12篇 |
1973年 | 15篇 |
排序方式: 共有3593条查询结果,搜索用时 78 毫秒
1.
2.
3.
4.
Evaluation of polymerase chain reaction and adenosine deaminase assay for the diagnosis of tuberculous effusions in children. 总被引:2,自引:0,他引:2
AIM: To evaluate and compare the utility of polymerase chain reaction (PCR) for the diagnosis of tuberculous effusions in children. METHODS: PCR, adenosine deaminase (ADA) activity and absolute lymphocyte count (ALC) were evaluated in the fluid of 31 tuberculous (20 pleural, 8 ascites and 3 pericardial) and 24 non-tuberculous (10 transudtative ascites, 8 empyema thoracis, 3 malignant pleural and 3 pyopericardium) effusions. RESULTS: Fluid PCR for Mycobacterium tuberculosis was positive in 74% of tuberculous effusions, whereas it was falsely positive in 13% of the non-tuberculous group. The mean fluid ADA and ALC values were significantly higher in tuberculous effusions than in non-tuberculous effusions (p<0.001). The sensitivity and specificity of PCR, ADA (> or =38 IU/l) and ALC (> or =275/mm3) were 74% and 88%, 81% and 75%, and 90% and 83%, respectively, in diagnosing tuberculous effusions. The sensitivity of PCR, ADA and ALC was 100%, 100% and 88%, respectively, for confirmed tuberculous effusions. When the two tests were combined (either/or positive), the sensitivity increased (90-100%) at the expense of specificity. When both the tests were positive, then the specificity markedly increased (92-96%), but sensitivity of the tests decreased. CONCLUSION: Fluid PCR alone should not be relied on as a single test; rather, combined analysis with either ADA or ALC could be more useful in the diagnosis of tuberculous effusions in children. 相似文献
5.
MUAMMER SEYHAN BAAK KANDI COKUN HÜLYA SALAM HAMDI ÖZCAN YELDA KARINCAOLU 《Pediatrics international》2006,48(6):525-530
BACKGROUND: The present study was aimed to define the gender ratio, familial occurrence, age of onset, precipitating factors, clinical types, nail and joint involvement of psoriasis in childhood and adolescence in Turkey. METHODS: A total of 61 children with psoriasis under 18 years old were evaluated retrospectively, for age, gender, age of disease onset, family history, concomitant disease, the clinical type of psoriasis, clinical localization, nail and joint involvement and treatment modalities. RESULTS: Of the patients, 23 (37.70%) were boys and 38 (62.30%) were girls. Mean age was 9.28 +/- 4.02 years in girls and 11.18 +/- 3.85 years in boys (9.96 +/- 4.03 years in all children). Mean age at the onset of the disease was 6.81 +/- 4.11 years in girls and 7.03 +/- 4.28 years in boys (6.89 +/- 4.14 years in all patients). In 14 (23%) cases, a positive family history was detected. The most frequent probable triggering factors were upper respiratory tract infections (14.8%) and positive throat culture for A group ss-hemolytic streptococcus (21.3%). Frequency of emotional stress and psychiatric morbidity were 54% and 9.8%, respectively. The most frequent localizations at onset were trunk (44.3%), extremities (54.0%), and scalp (36.0%). Three children (4.9%) had a history of dissemination from psoriatic diaper rash. In total, 51 (83.6%) patients presented with psoriasis vulgaris, eight (13.1%) with generalized pustular psoriasis, and the remaining two (3.3%) with erythrodermic psoriasis. CONCLUSION: The incidence of psoriasis among dermatological patients in childhood and adolescence was 3.8%. The disease tends to appear earlier in girls than boys. The authors suggested that stress and upper respiratory infections are the most important triggering factors in childhood and adolescence psoriasis. 相似文献
6.
V Aerra M Kuduvalli AN Moloto AK Srinivasan AD Grayson BM Fabri AY Oo 《Journal of cardiothoracic surgery》2006,1(1):6-5
Background
Atrial fibrillation can occur in up to 40% of patients undergoing coronary surgery. 相似文献7.
I(indigenous)-compounds are age-related, carcinogen adduct-like, putative indigenous DNA modifications detectable by 32P-postlabeling assay in untreated animals. To investigate the origins of these DNA derivatives, we examined the effects of dietary vitamin E, a natural antioxidant, on I-compounds of rat liver and kidney DNA. Weanling female Sprague-Dawley rats were fed Draper's diets containing 0, 100, 1000, or 10,000 mg/kg alpha-tocopheryl acetate for 6 mo. The DNA from four individual rats of each group was analyzed by a nuclease P1-enhanced version of the 32P-postlabeling assay for DNA adducts. The amount of vitamin E in the liver was measured by high performance liquid chromatography. Rats fed vitamin E-deficient diet (0 mg/kg) showed identical profiles and similar levels of I-compounds as those fed the 100 mg/kg diet. Most I-spots were significantly intensified and one tissue-specific extra spot was found in both liver and kidney DNA of rats fed the 1000 or 10,000 mg/kg vitamin E diet. However, one of the five major I-spots detected in the kidney was weaker in the 1000 and 10,000 mg/kg groups than in the 0 and 100 mg/kg groups. These results show that formation of most I-compounds was not affected by vitamin E-deficient diet, and that long-term feeding of diet containing high levels of vitamin E may cause metabolic alterations leading to an increased formation of DNA-reactive (potentially mutagenic or carcinogenic) electrophiles. 相似文献
8.
S Sharma R Narula R Nath S K Thind 《Journal of nutritional science and vitaminology》1990,36(6):579-586
The intestinal uptake of [14C]oxalate, [14C]glyoxylate, and [14C]glycolate are studied in brush border membrane vesicles (BBMV) isolated from vitamin A-deficient and pair-fed control rats. The data obtained indicate that oxalate and its precursors are transported across the BBMV by passive diffusion. The intestinal uptake of glyoxylate and glycolate remains unaltered in vitamin A deficiency, while uptake rate of oxalate was significantly increased (p less than 0.01) in vitamin A-deficient rats as compared to pair-fed controls. In conclusion, the results indicate that vitamin A deficiency leads to hyperabsorption of oxalate through the gut. 相似文献
9.
10.