全文获取类型
收费全文 | 2466篇 |
免费 | 145篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 71篇 |
儿科学 | 164篇 |
妇产科学 | 32篇 |
基础医学 | 306篇 |
口腔科学 | 56篇 |
临床医学 | 210篇 |
内科学 | 592篇 |
皮肤病学 | 34篇 |
神经病学 | 97篇 |
特种医学 | 486篇 |
外科学 | 214篇 |
综合类 | 38篇 |
预防医学 | 101篇 |
眼科学 | 18篇 |
药学 | 104篇 |
中国医学 | 4篇 |
肿瘤学 | 109篇 |
出版年
2022年 | 14篇 |
2021年 | 36篇 |
2020年 | 16篇 |
2019年 | 22篇 |
2018年 | 28篇 |
2017年 | 19篇 |
2016年 | 35篇 |
2015年 | 50篇 |
2014年 | 52篇 |
2013年 | 87篇 |
2012年 | 68篇 |
2011年 | 76篇 |
2010年 | 100篇 |
2009年 | 81篇 |
2008年 | 90篇 |
2007年 | 66篇 |
2006年 | 72篇 |
2005年 | 57篇 |
2004年 | 66篇 |
2003年 | 45篇 |
2002年 | 51篇 |
2001年 | 39篇 |
2000年 | 49篇 |
1999年 | 58篇 |
1998年 | 143篇 |
1997年 | 126篇 |
1996年 | 127篇 |
1995年 | 96篇 |
1994年 | 79篇 |
1993年 | 88篇 |
1992年 | 47篇 |
1991年 | 32篇 |
1990年 | 24篇 |
1989年 | 63篇 |
1988年 | 46篇 |
1987年 | 59篇 |
1986年 | 51篇 |
1985年 | 55篇 |
1984年 | 30篇 |
1983年 | 36篇 |
1982年 | 40篇 |
1981年 | 22篇 |
1980年 | 38篇 |
1979年 | 20篇 |
1978年 | 17篇 |
1977年 | 23篇 |
1976年 | 27篇 |
1975年 | 25篇 |
1972年 | 8篇 |
1966年 | 6篇 |
排序方式: 共有2636条查询结果,搜索用时 15 毫秒
1.
Dana Franzen-Klein Mark Jankowski Charlotte L. Roy Hoa Nguyen-Phuc Da Chen Lorin Neuman-Lee 《Journal of toxicology and environmental health. Part A》2020,83(2):45-65
ABSTRACTDomestic chickens (Gallus gallus domesticus) were exposed to imidacloprid by gavage once daily for 7 consecutive days at 0, 0.03, 0.34, 3.42, 10.25, and 15.5 mg/kg/day (n = 20 per group; 5 6-week-old males, 5 6-week-old females, 5 9-week-old males, and 5 9-week-old females). The severity and duration of neurobehavioral abnormalities were recorded. Components of the innate and adaptive immune system were assessed with 7 standard functional assays. Temporary neurobehavioral abnormalities were observed in a dose-dependent manner, including muscle tremors, ataxia, and depressed mentation. Based upon mean clinical severity scores, the no observed adverse effect level (NOAEL) was 3.42 mg/kg/day, and the lowest observed adverse effect level (LOAEL) was 10.25 mg/kg/day. The effective dose value for the presence of any neurobehavioral abnormalities in 50% of the test group (ED50) was 4.62 ± 0.98 mg/kg/day. The ED50 for an adjusted score that included both severity and duration of neurobehavioral abnormalities was 11.24 ± 9.33 mg/kg/day. These ED50 values are equivalent to a 1 kg bird ingesting 29 or 70 imidacloprid treated soybean seeds respectively. Immunotoxicity was not documented, possible causes include the assays were insensitive, relevant immune functions were not examined, or imidacloprid is not immunotoxic at this dosing schedule in this species. Neurobehavioral abnormalities were a more sensitive indicator of the sublethal effects of imidacloprid than immunotoxicity. 相似文献
2.
JA HYEON KU CHEOL KWAK SEUNG-JUNE OH EUNSIK LEE SANG EUN LEE JAE-SEUNG PAICK 《International journal of urology》2004,11(7):489-493
BACKGROUND: Our aims in the present study were to estimate the influences of pain and urinary symptoms on quality of life, and to determine which of these two variables has the most predictive power with respect to quality of life in young men with chronic prostatitis-like symptoms. METHODS: Chronic prostatitis-like symptoms were measured by the National Institutes of Health-Chronic Prostatitis Symptom Index. Of the 28,841 men aged 20 years who lived in the study community, 18,495 men (a response rate 64.1%) agreed to participate in the study. A total of 1057 men who complained of symptoms indicative of chronic prostatitis were included in the study. The influences of pain and urinary symptoms on quality of life were determined using logistic regression analysis. The receiver operating characteristic (ROC) curve was used to estimate the predictive ability of each of these variables with respect to quality of life. RESULTS: Results from multivariate analysis showed that both pain and urinary symptoms were associated with an increased likelihood of impaired quality of life, although pain contributed more to a reduced quality of life than urinary symptoms. Relative to men who experienced mild pain, men who experienced moderate pain had a 3.9-fold risk of poor quality of life (odds ratio [OR], 3.87; 95% confidence interval [CI], 2.86-5.23; P < 0.001) and those who experienced severe pain had a 15.7-fold risk of reduced quality of life (OR, 15.68; 95% CI, 6.59-37.35; P < 0.001). Moderate urinary symptoms were associated with a 1.4-fold risk of bother (OR, 1.41; 95% CI, 1.01-1.99; P < 0.001) and severe urinary symptoms were associated with 2.4-fold risk (OR, 2.39; 95% CI, 1.37-4.12; P < 0.001), relative to mild urinary symptoms. Comparison of the effects of pain and urinary symptoms showed that pain severity had the most predictive power for bother, quality of life, and quality-of-life impact. The areas under the ROC curves for bother, quality of life, and quality-of-life impact were 71.3%, 69.3% and 72.5%, respectively. CONCLUSION: Urinary symptoms and pain might be associated with an increased likelihood of impaired quality of life in young men with chronic prostatitis-like symptoms. In addition, our findings suggest that pain severity is the most influential variable for determining quality of life in this population. 相似文献
3.
4.
5.
6.
7.
8.
9.
Gene amplification is an important mechanism of increased gene expression in a number of human solid tumors. We have recently identified and cloned sequences from a novel DNA amplification unit in malignant fibrous histiocytoma. The amplified sequences are derived from chromosome 12q13-14 and encode a gene designated SAS (sarcoma amplified sequence). In the present study, a series of soft tissue sarcomas was studied to characterize further the phenomenon of SAS amplification. Seven of 22 (32%) malignant fibrous histiocytomas and three liposarcomas contained SAS amplification. Strikingly, all of the tumors with SAS amplification occurred in central sites (i.e., in the abdominal or inguinal regions) rather than in the extremities (i.e., in the arms of legs). These observations demonstrate that SAS amplification occurs with a significant frequency in mesenchymal tumors and is particularly associated with abdominal disease. 相似文献
10.