全文获取类型
收费全文 | 3851篇 |
免费 | 230篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 160篇 |
妇产科学 | 142篇 |
基础医学 | 377篇 |
口腔科学 | 95篇 |
临床医学 | 286篇 |
内科学 | 665篇 |
皮肤病学 | 63篇 |
神经病学 | 162篇 |
特种医学 | 247篇 |
外科学 | 619篇 |
综合类 | 263篇 |
一般理论 | 2篇 |
预防医学 | 279篇 |
眼科学 | 112篇 |
药学 | 332篇 |
中国医学 | 69篇 |
肿瘤学 | 209篇 |
出版年
2023年 | 37篇 |
2022年 | 86篇 |
2021年 | 125篇 |
2020年 | 75篇 |
2019年 | 117篇 |
2018年 | 144篇 |
2017年 | 80篇 |
2016年 | 96篇 |
2015年 | 120篇 |
2014年 | 159篇 |
2013年 | 164篇 |
2012年 | 277篇 |
2011年 | 299篇 |
2010年 | 218篇 |
2009年 | 163篇 |
2008年 | 192篇 |
2007年 | 205篇 |
2006年 | 184篇 |
2005年 | 154篇 |
2004年 | 125篇 |
2003年 | 137篇 |
2002年 | 92篇 |
2001年 | 56篇 |
2000年 | 45篇 |
1999年 | 49篇 |
1998年 | 65篇 |
1997年 | 69篇 |
1996年 | 66篇 |
1995年 | 45篇 |
1994年 | 45篇 |
1993年 | 40篇 |
1992年 | 36篇 |
1991年 | 25篇 |
1990年 | 22篇 |
1989年 | 42篇 |
1988年 | 28篇 |
1987年 | 32篇 |
1986年 | 23篇 |
1985年 | 15篇 |
1984年 | 20篇 |
1983年 | 11篇 |
1982年 | 22篇 |
1981年 | 12篇 |
1980年 | 17篇 |
1978年 | 5篇 |
1977年 | 10篇 |
1976年 | 13篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1973年 | 5篇 |
排序方式: 共有4115条查询结果,搜索用时 15 毫秒
51.
Fatty acid balance studies in term infants fed formula milk containing long-chain polyunsaturated fatty acids 总被引:1,自引:0,他引:1
C Morgan L Davies F Corcoran J Stammers J Colley SA Spencer D Hull 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(2):136-142
Long-chain polyunsaturated fatty acids (LCP) are thought to be required for optimal nervous system development in the newborn. A commercial milk formula containing LCP (Aptamil-LCP) with a fatty acid profile closely resembling breast milk, has recently been introduced for term infants. The absorption of fatty acids in term infants was examined in a double-blind randomized controlled trial comparing Aptamil-LCP ( n = 20) and standard Aptamil ( n = 20). Formula-fed newborn infants were studied from birth for 14 d. Fat balances (3 d) were performed from d 10. A 3-d stool collection was performed from d 10 in a parallel breastfed group ( n = 21). Plasma samples were taken on d 6. Median fat excretion (mg kg−1 ) was 897.1, 615.0 and 355.2 with Aptamil, Aptamil-LCP and breastfeeding, respectively. The median total fat absorption coefficient in Aptamil-LCP-fed infants was higher than in those fed standard Aptamil ( p < 0:01). These findings were accounted for by differences in the excretion and absorption of long-chain saturated fatty acids (C14:0, C16:0 and C18:0). Higher fat excretion was associated with bulkier and firmer stools. Only trace amounts of LCP were detected in the stools of all groups. This accounted for less than 4% of dietary intake in Aptamil-LCP-fed infants. No differences in the utilization of LCP from Aptamil-LCP and breast milk feeding were apparent. Plasma phospholipid fatty acid composition data reflected differences in dietary LCP intake. Thus, PL LCP levels were highest in the breastfed infants and lowest in the Aptamil-fed infants, with values for the Aptamil-LCP-fed group falling in between. 相似文献
52.
Characterization of the insulin-like growth factor axis in a human hepatoma cell line (PLC) 总被引:4,自引:0,他引:4
Scharf JG; Schmidt-Sandte W; Pahernik SA; Ramadori G; Braulke T; Hartmann H 《Carcinogenesis》1998,19(12):2121-2128
53.
54.
Thaer S. Alomar Khalid Mahmood Simon O’Connor Keith Robson Harminder S. Dua 《International ophthalmology》2013,33(5):561-565
Crystalline corneal deposits have been well reported in individual cases of lymphoproliferative disorders associated with hyper-gammaglobulinemia, hence called ‘Crystalline Paraproteinemic Keratopathy’. This is the first report of corneal deposits in a case of localised conjunctival B-cell Lymphoma without paraproteinaemia/hyper-gammaglobulinemia, hence called ‘Presumed Paraproteinic Crystalline Keratopathy’. 相似文献
55.
Leila Sabzmakan Mahmood Ghasemi Mohammad Asghari Jafarabadi Tahereh Kamalikhah Mosharafeh Chaleshgar Kordasiabi 《Substance use & misuse》2018,53(9):1511-1518
Background: Tobacco use is a significant predisposing factor to many diseases. Protection motivation theory is a well-suited theory, since fear can motivate individuals to change their unhealthy behaviors. Objective: This study was conducted to examine the associations between the constructs of this theory with intention and tobacco use behavior. Method: The present cross-sectional study was conducted in Noshahr, Iran. The participants were 440 high school boys selected using a stratified random sampling in 2016. A questionnaire about tobacco use based on protection motivation theory was developed and its validity and reliability were assessed. The questionnaire included the demographic information, the constructs of theory, and tobacco use behavior. Structural equation modeling was used to test the associations between the constructs with intention and tobacco use. Results: The variables of perceived vulnerability (β = 0/137, P < 0.001), fear (β = 0/149, P < 0.001), self-efficacy (β = 0/249, P < 0.001), perceived intrinsic reward (β = ?0.285, P < 0.001), threat appraisal (β = ?0.25, P < 0.001), and coping appraisal (β = 0.358, P < 0.001) had direct effect and are significant with intention. Moreover, perceived vulnerability (β = ?0.158, P < 0.001), fear (β = ?0.172, P < 0.001), self-efficacy (β = ?0.288, P < 0.001), perceived intrinsic reward (β = 0.329, P < 0.001), threat appraisal (β = 0.265, P < 0.001), and coping appraisal (β = ?0.379, P < 0.001) affected tobacco use indirectly through intention and were significantly associated with behavior. Also, intention had direct effect and is significant with tobacco use (β = ?1.156, P < 0.001). Conclusions: The protection motivation theory provides a useful framework for investigating factors of tobacco use among male students. Future tobacco prevention interventions should focus on increasing the vulnerability and fear, decreasing intrinsic reward, and improving self-efficacy to reduce tobacco use. 相似文献
56.
57.
58.
Ehsan Hejazi Maryam Tavakoli Mahmood Jeddi-Tehrani Masoud Kimiagar Jalal Hejazi Mohammad Houshyari 《Nutrition and cancer》2017,69(7):1036-1042
Background: One major concern in the treatment of cancer patients during chemotherapy is drug resistance. Here we investigated the effects of soy isoflavone extracts alone or in combination with Docetaxel on the drug resistance, angiogenesis, apoptosis, and tumor volume in mouse 4T1 breast tumor model. Methods: Sixty female BALB/c mice were randomly divided into 4 groups: control, dietary soy isoflavone extract [Iso, 100 mg/kg diet (0.01%)], Docetaxel (10 mg/kg) injection, and the combination of dietary soy isoflavone extract and intravenous Docetaxel injection (Docetaxel + Iso). One week after the third injection, the breast tumors of eight mice from each group were excised to analyze NF-κBp65′ vascular endothelial growth factor receptor-2 (VEGFR2) and Pgp gene and protein expressions and the other seven mice were monitored for survival rate analysis until they died. Results: NF-κBp65 gene and protein expressions were significantly lower in the Docetaxel + Iso group in comparison with that of the Docetaxel group. VEGFR2 protein expression in the Docetaxel + Iso and Iso groups was significantly lower than that of the Docetaxel group. Conclusion: These findings may indicate that the combined use of isoflavone extracts together with chemotherapeutic agents has more efficient anti-carcinogenic effects than their individual use. 相似文献
59.
Mahmood Ahmadi-hamedani Zohreh Khaki Sadegh Rahbari Mahnaz A. Ahmadi-hamedani 《Comparative clinical pathology》2012,21(6):1179-1182
This study was conducted to measure selected hematological parameters in goats naturally infected with Anaplasma ovis. In this study 193 blood samples were collected from adult and young goats in north (Gonbad) and northeast (Mashhad) of Iran. Out of the 193 blood samples, 123 samples were positive (infected group) and 70 samples were negative (uninfected group) for A. ovis by polymerase chain reaction. Hematological analysis was carried out on 47 samples from the infected group and 37 samples from the uninfected group. Hematological analysis indicated significant decreases (P?<?0.01) in RBC counts, HCT values, and hemoglobin concentrations in the A. ovis-infected group of goats compared to the uninfected group (P?<?0.01). The mean corpuscular volume, mean corpuscular hemoglobin, WBC counts, lymphocytes, eosinophils, and monocytes in the infected group were lower but neutrophils were higher than in the uninfected group. These differences were not statistically significant (P?>?0.05). The result from this study revealed that A. ovis infection in goats is associated with marked changes in hematological parameters. 相似文献
60.