全文获取类型
收费全文 | 1530篇 |
免费 | 177篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 145篇 |
妇产科学 | 25篇 |
基础医学 | 201篇 |
口腔科学 | 90篇 |
临床医学 | 161篇 |
内科学 | 289篇 |
皮肤病学 | 49篇 |
神经病学 | 30篇 |
特种医学 | 186篇 |
外科学 | 228篇 |
综合类 | 38篇 |
预防医学 | 98篇 |
眼科学 | 40篇 |
药学 | 54篇 |
中国医学 | 2篇 |
肿瘤学 | 93篇 |
出版年
2023年 | 14篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 14篇 |
2019年 | 7篇 |
2018年 | 44篇 |
2017年 | 47篇 |
2016年 | 42篇 |
2015年 | 60篇 |
2014年 | 76篇 |
2013年 | 107篇 |
2012年 | 48篇 |
2011年 | 35篇 |
2010年 | 78篇 |
2009年 | 92篇 |
2008年 | 34篇 |
2007年 | 51篇 |
2006年 | 53篇 |
2005年 | 29篇 |
2004年 | 31篇 |
2003年 | 14篇 |
2002年 | 19篇 |
2001年 | 15篇 |
2000年 | 9篇 |
1999年 | 24篇 |
1998年 | 101篇 |
1997年 | 87篇 |
1996年 | 99篇 |
1995年 | 63篇 |
1994年 | 74篇 |
1993年 | 39篇 |
1992年 | 15篇 |
1991年 | 21篇 |
1990年 | 13篇 |
1989年 | 31篇 |
1988年 | 29篇 |
1987年 | 28篇 |
1986年 | 26篇 |
1985年 | 24篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 16篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1975年 | 9篇 |
1966年 | 1篇 |
排序方式: 共有1735条查询结果,搜索用时 0 毫秒
991.
The findings at magnetic resonance (MR) imaging of eight patients with primary tumors of the foot were compared with those at gross pathologic examination. In all cases, there was excellent correlation between the two studies. When compared with computed tomography (CT), MR imaging was superior in defining the presence and extent of local disease. While the appearances of various foot neoplasms are nonspecific, the ease of multiplanar imaging, the superior contrast resolution, and the sensitivity to marrow abnormalities are major advantages of MR imaging over CT in staging foot neoplasms. These advantages are crucial when foot-sparing curative resection of a malignancy is contemplated. The combination of plain radiography and MR imaging may be all that is necessary for optimal preoperative detection and local staging of tumors of the foot. 相似文献
992.
993.
To determine the optimal site for antegrade puncture of the femoral artery, the authors evaluated three cadaver specimens and computed tomographic (CT) scans of 50 patients. The relationships among the common femoral artery, the femoral artery bifurcation, the center of the femoral head, and the inguinal ligament were evaluated. CT showed that the center of the femoral head was always located caudal to the level of the inguinal ligament but cranial to the bifurcation of the common femoral artery. Therefore, the femoral head seems to provide a reliable landmark for entering the common femoral artery. 相似文献
994.
995.
996.
997.
Multicore myopathy with restrictive cardiomyopathy 总被引:1,自引:0,他引:1
MAAP Willemsen AM van Oort HJ ter Laak RCA Sengers FJM Gabreëls 《Acta paediatrica (Oslo, Norway : 1992)》1997,86(11):1271-1274
A 10-y-old girl is presented who suffered mild muscular weakness and exercise intolerance from the age of 1 y onwards, with progression appearing from the age of about 8 y. Multicore myopathy and restrictive cardiomyopathy were diagnosed. Literature concerning the coexistence of multicore myopathy and cardiomyopathy is reviewed. 相似文献
998.
LB Dixon J McKenzie BM Shannon DC Mitchell H Smiciklas-Wright AM Tershakovec 《Pediatrics》1997,100(5):863-872
OBJECTIVE: To determine how young children changed their overall diet when they changed their fat intake after 3 months of participating in a nutrition education demonstration study designed to lower low-density lipoprotein cholesterol and cardiovascular risk. METHODS: Three 24-hour dietary recalls were collected from 303 4- to 10-year-old children at baseline and 3 months later. At both times, mean number of servings from food groups, grams of fat contributed from food groups, and intake of calories and nutrients were calculated and compared among quartiles of children formed according to change in their percent of calories from total fat after 3 months. RESULTS: Children who reduced their percent of calories from total fat most (ie, by an average of 8.5%) after 3 months consumed fewer servings from meats, eggs, dairy, fats/oils, and breads but tended to increase their number of servings from lower-fat foods within those food groups, particularly from dairy foods. These children also increased their mean intake of fruits, vegetables, and desserts, and maintained average intakes of all nutrients (except vitamin D) in excess of two thirds of the respective recommended dietary allowance. CONCLUSIONS: Young children who reduced their percent of calories from total fat in accordance with the current National Cholesterol Education Program recommendations accomplished this by reducing their overall intake of higher-fat foods, replacing higher-fat foods with lower-fat foods within several food groups, particularly within the dairy group (eg, drinking skim milk instead of whole milk) and by consuming more servings of fruits, vegetables, and very-low-fat desserts. These behaviors did not compromise their mean calorie or nutrient intakes, showing that it is possible for young children to lower their fat intake safely to reduce their risk of future heart disease. 相似文献
999.
1000.
We reported recently that weight cycling significantly increased the
incidence of mammary cancer in virgin female rats that were pretreated with
N-methyl-N-nitrosourea. The present study investigated the effect of weight
cycling on mammary epithelial cell proliferation and its relationship to
changes in plasma insulin, estrogen, progesterone and urinary
corticosterone in 30 female virgin Sprague-Dawley rats. Animals were fed a
modified AIN-76A diet containing 24.6% corn oil by weight. Weight-cycled
(WC) rats were food restricted daily by either 33% or 50% of non-restricted
controls for 1 week followed by 3 weeks compensatory refeeding and weight
recovery over 18 weeks or 4.5 weight cycles. WC rats consumed 6-10% less
food than controls (P = 0.01) but showed a 71- 89% greater efficiency of
food utilization for growth (P < 0.0001) than controls. There were no
differences in total weight gain during treatment. Mammary lobuloalveolar
and ductal cell proliferation of WC rats, measured by
5-bromo-2'deoxyuridine labelling, increased in a dose- response fashion, P
= 0.03, P = 0.06 respectively in comparison to controls. Energy and
substrate utilization measured by indirect calorimetry indicated WC animals
expended less energy (P = 0.005) and utilized less glucose (P = 0.0001) and
protein (P = 0.006) during restriction, and less lipid during recovery (P =
0.05) than controls. There were no significant differences in hormone
levels between groups. Multiple regression analysis with plasma insulin,
estrogen, progesterone and urinary corticosterone as independent variables
(r = 0.947, r2 = 0.897, P = 0.003) showed that plasma insulin was the only
significant predictor (P < 0.01) of mammary cell proliferation. In
accord with this observation, tyrosine-phosphorylated activation of insulin
receptor substrate-1, detected by immunoprecipitation and Western
immunoblot analysis in mammary tumors of WC rats from our previous study,
was 3-5 times greater than in non-restricted controls (P < 0.01).
Present findings suggest that weight cycling in rats increases risk of
breast cancer development via insulin stimulated mammary cell
proliferation.
相似文献