全文获取类型
收费全文 | 1667篇 |
免费 | 102篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 122篇 |
儿科学 | 115篇 |
妇产科学 | 79篇 |
基础医学 | 239篇 |
口腔科学 | 64篇 |
临床医学 | 97篇 |
内科学 | 290篇 |
皮肤病学 | 34篇 |
神经病学 | 206篇 |
特种医学 | 45篇 |
外科学 | 146篇 |
综合类 | 21篇 |
预防医学 | 118篇 |
眼科学 | 13篇 |
药学 | 90篇 |
肿瘤学 | 95篇 |
出版年
2022年 | 10篇 |
2021年 | 19篇 |
2020年 | 15篇 |
2019年 | 15篇 |
2018年 | 18篇 |
2017年 | 13篇 |
2016年 | 24篇 |
2015年 | 22篇 |
2014年 | 28篇 |
2013年 | 39篇 |
2012年 | 67篇 |
2011年 | 73篇 |
2010年 | 47篇 |
2009年 | 39篇 |
2008年 | 45篇 |
2007年 | 58篇 |
2006年 | 72篇 |
2005年 | 70篇 |
2004年 | 67篇 |
2003年 | 69篇 |
2002年 | 80篇 |
2001年 | 88篇 |
2000年 | 72篇 |
1999年 | 57篇 |
1998年 | 33篇 |
1997年 | 19篇 |
1996年 | 23篇 |
1995年 | 18篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 43篇 |
1991年 | 45篇 |
1990年 | 34篇 |
1989年 | 31篇 |
1988年 | 32篇 |
1987年 | 32篇 |
1986年 | 34篇 |
1985年 | 42篇 |
1984年 | 10篇 |
1983年 | 21篇 |
1982年 | 10篇 |
1979年 | 26篇 |
1976年 | 10篇 |
1975年 | 12篇 |
1974年 | 12篇 |
1973年 | 18篇 |
1972年 | 15篇 |
1971年 | 13篇 |
1970年 | 11篇 |
1969年 | 12篇 |
排序方式: 共有1774条查询结果,搜索用时 15 毫秒
991.
Jiang R Chang X Stoll B Ellis KJ Shypailo RJ Weaver E Campbell J Burrin DG 《The Journal of nutrition》2000,130(8):2016-2019
We compared the effects of supplementing either animal plasma or extruded soy protein in the diet based on the efficiency of dietary protein utilization for lean tissue growth in early-weaned pigs. Twenty-four 14-d-old pigs (4 kg body weight) were pair-fed (per kg body weight) either a control diet containing extruded soy protein (C; n = 12) or a diet with 10% animal plasma (P; n = 12) for 24 d. During the 24 days, protein intake was not different, yet mean daily body weight gains (+23%) and food conversion efficiencies (expressed as the ratio of body weight gain to protein intake) (+19%) were greater (P < 0.05) in the P group than in the C group. Lean body mass measured after 24 d, using both dual-energy X-ray absorptiometry and total body potassium analysis, was significantly (P < 0.05) greater (approximately 16%) in P than in C pigs. The circulating urea concentrations were 40% lower (P < 0.05) in P than in C pigs. Our results demonstrate that supplementing early-weaned pig diets with animal plasma rather than extruded soy protein increased the efficiency of dietary protein use for lean tissue growth and that this response is mediated in part by decreased amino acid catabolism. 相似文献
992.
Prenatal diagnosis performed by fetal karyotype and ultrasound scan is now a routine part of antenatal care in many countries. How many fetal anomalies are actually detected by these procedures? We have used our registry of congenital malformations to answer this question. In our region, prenatal diagnosis was performed in 23.1 per cent of fetuses with a chromosomal aberration and in 20.1 per cent of fetuses with non-chromosomal anomalies. Only 6.9 per cent of the pregnancies with fetuses with non-chromosomal anomalies were terminated. The sensitivity of prenatal diagnosis by ultrasonographic examination was much lower for isolated malformations (fetuses with only one anomaly) than for multiple malformed children, 15.3 and 48.3 per cent respectively, chromosomal anomalies excluded. 相似文献
993.
Chronic treatment with highly active analogs of luteinizing hormone (LH)-releasing hormone (LH-RH) induces "paradoxical" antifertility effects. Intact male rats, a reduction in testosterone production is observed after the administration of [D-Ser(But)6]-LH-RH(1-9)ethylamide (burserelin, Hoe 766), 50 ng/day subcutaneously for 4 weeks. In castrated male rats treated with the same dose of analog, plasma LH levels were reduced from days 14 to 28 and plasma follicle-stimulating hormone (FSH) levels were reduced from days 21 to 28 of treatment. Pituitary LH and FSH concentrations were also decreased. The plasma prolactin level was reduced at 14 days of treatment. The hypothalamic LH-RH content remained unchanged and the adrenal corticosterone content was lowered. These findings indicate a direct inhibitory effect of the analog on gonadotropin secretion in the absence of the gonads, and may explain some paradoxical antifertility effects observed with high doses of LH-RH analogs which exceed the physiologic dose range. 相似文献
994.
Giardia lamblia infections in a cohort of Bangladeshi mothers and infants followed for one year 总被引:7,自引:0,他引:7
A Islam B J Stoll I Ljungstr?m J Biswas H Nazrul G Huldt 《The Journal of pediatrics》1983,103(6):996-1000
Giardia lamblia infection in an endemic area was investigated by following a cohort of 33 lactating mothers and their infants in a semiurban community of Bangladesh for one year. Eighty-two percent of mothers and 42% of infants excreted Giardia at least once during the study period. Infants became infected as early as 3 months of age, and 86% of the infected infants had diarrhea, suggesting that the first exposure to the parasite results in disease. Only one of the infected mothers had diarrhea, indicating that with repeated exposure to Giardia, mothers in an endemic area may develop partial immunity that protects against disease but not infection. An interrelationship between maternal and infant colonization was not found. Local and systemic immune responses to Giardia correlated poorly with infection, but milk antibodies were a better reflection of infection than serum antibodies were. Infection with G. lamblia was significantly lower in infants younger than 6 months (9%), an age when many are totally breast-fed. However, we were unable to establish clear-cut protection related to human milk antibodies, and suggest that the lower infection rate in younger infants results mainly from decreased exposure to Giardia cysts. 相似文献
995.
Dallenbach-Hellweg G. Weber J. Stoll P. Velten C. H. 《Archives of gynecology and obstetrics》1971,210(3):303-320
Archives of Gynecology and Obstetrics - Anhand von 8 Fällen mit Endometriumveränderungen bei jungen Frauen, die aufgrund der histologischen Befunde ohne Kenntnis des Alters der Patientin... 相似文献
996.
997.
998.
999.
1000.