全文获取类型
收费全文 | 421篇 |
免费 | 33篇 |
国内免费 | 105篇 |
专业分类
儿科学 | 27篇 |
妇产科学 | 4篇 |
基础医学 | 44篇 |
口腔科学 | 32篇 |
临床医学 | 104篇 |
内科学 | 105篇 |
皮肤病学 | 6篇 |
神经病学 | 8篇 |
特种医学 | 69篇 |
外科学 | 23篇 |
综合类 | 37篇 |
预防医学 | 12篇 |
眼科学 | 5篇 |
药学 | 51篇 |
中国医学 | 1篇 |
肿瘤学 | 31篇 |
出版年
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 11篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 9篇 |
2011年 | 11篇 |
2010年 | 17篇 |
2009年 | 17篇 |
2008年 | 4篇 |
2007年 | 58篇 |
2006年 | 12篇 |
2005年 | 24篇 |
2004年 | 14篇 |
2003年 | 10篇 |
2002年 | 14篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 6篇 |
1998年 | 45篇 |
1997年 | 35篇 |
1996年 | 38篇 |
1995年 | 17篇 |
1994年 | 22篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 3篇 |
1990年 | 11篇 |
1989年 | 13篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1965年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有559条查询结果,搜索用时 10 毫秒
11.
12.
13.
目的:观察多聚二磷酸腺苷(ADP)核糖合成酶(PARP)抑制剂对血管紧张素Ⅱ(AngⅡ)刺激的乳鼠心脏心肌重构的预防作用.方法:新生大鼠心肌细胞原代培养,传代,用PARP抑制剂3-AB预处理细胞,观察PARP抑制剂对AngⅡ诱导心肌细胞PARP激活、PARPl表达,细胞内ROS产生和c-fos,ANP,β/aMHC基因表达的影响.结果:AngⅡ显著诱导心肌细胞PARP激活,ROS产生增加,PARPl、c-los、β/a-MHC、ANP基因表达增加.给予3-AB预处理可显著抑制AngⅡ诱导的上述变化.结论:AngⅡ可以诱导培养的心肌细胞内PARP激活,PARPl蛋白表达增加,3-AB预处理可以明显降低AngⅡ诱导的心肌细胞内异常基因表达增加,提示PARPl参与了心室重构的发生发展过程. 相似文献
14.
15.
Is fecundability associated with month of birth? An analysis of 19th and early 20th century family reconstitution data from The Netherlands 总被引:1,自引:4,他引:1
Smits LJ; Van Poppel FW; Verduin JA; Jongbloet PH; Straatman H; Zielhuis GA 《Human reproduction (Oxford, England)》1997,12(11):2572-2578
The relationship between fecundability and month of birth was investigated
in a cohort of 1526 women who married between 1802 and 1929, using only
women whose first marriage occurred before the age of 35 years. On the
basis of their time to pregnancy (TTP, calculated as time between wedding
and first birth minus gestational length), women were categorized into two
groups: fecunds (TTP up to 12 months or prenuptial conceptions, n = 1348)
and subfecunds (TTP >18 months, n = 118). By use of logistic regression,
cosinor functions with a period of 1 year or 6 months and variable shift
and amplitude were fitted through the monthly odds of subfecunds versus
fecunds. The best fitting curve was unimodal, with a zenith in September (P
= 0.13 for H0: no differences). Exclusion of childless women (n = 36,
minimum follow-up 5 years) from the subfecunds led to a similar curve (P
< 0.01), while childless women, as compared with fecunds, showed a birth
distribution that was best represented with a bimodal curve with zeniths in
January and July (P = 0.06). This study provides evidence for the existence
of differences in fecundability by month of birth. The cause of this
relationship is unclear, but may lie in a melatonin-dependent circannual
variability of the quality of the oocyte.
相似文献
16.
17.
18.
Direct sagittal computed tomographic scanning (DSCT) of the shoulder was performed in 42 symptomatic patients, six healthy volunteers, and two cadaver shoulders. Axial CT scanning and double-contrast arthrography with plain radiographs were performed in 41 patients for comparison. DSCT enabled correct identification of 27 of 29 lesions in 24 patients. Seventeen patients had normal shoulders. Axial CT scanning and DSCT together enabled correct identification of all lesions and were markedly superior to plain-film arthrography. DSCT enabled diagnosis of all cases of complete rotator cuff tear plus three cases of incomplete tear and three of rotator cuff atrophy not identified by the other techniques. Axial CT scanning was better than DSCT for diagnosis of Bankart lesions. 相似文献
19.
LJ Gould J Mushkudiani H Hou OY Grinberg S Grinberg HM Swartz 《Wound repair and regeneration》2004,12(2):A29-A29
Methods to reliably measure tissue oxygenation in situ are currently lacking. We have developed a vertically oriented, dorsal, bipedicle flap model that is easy to perform, reliably reproduces tissue ischemia, eliminates craniocaudal variation, and is amenable to studying therapeutic modalities. The effect of narrowing this flap on tissue oxygenation measured with Licox electrodes has previously been presented. In this study we utilize in situ EPR spectroscopy to demonstrate the oxygen gradient in the flap as a function of flap width and placement of a silicone sheet directly under the flap. The effect of wound healing over a 2 week period is demonstrated. Twenty four, 300 gm male Sprague‐Dawley rats underwent creation of the bipedicle flap according to the following groups: 2.5 cm flap with silicone, 2.0 cm flap without silicone, 2.0 cm flap with silicone. Each group of 6 animals was injected with EMS char at 2 cm intervals along the flap and one injection in the control, non‐ischemic tissue. A 4th group underwent 2.0 cm flaps with silicone and use of lithium phthalocyanin as the paramagnetic material. Wound measurements and EPR spectroscopy were performed on days 3, 7, 10 and 14. On day 14, after EPR measurements, the animals were sacrificed and their wounds excised. One flap and one control wound were preserved for histologic analysis, the other flap and control wounds were prepared for lactate measurements. EPR spectroscopy demonstrated a gradient of oxygen that was lowest in the center of the flap and greatest at either end. Changes in the oxygen gradient correlated with narrowing and placement of the intervening silicone sheet. This new technology has never been utilized in an animal model of impaired wound healing. Comparison of recently developed paramagnetic materials for optimal tissue oxygen and free radical measurements will be presented. 相似文献
20.
LJ Salomon JP Bernard M Duyme Y Ville 《The journal of maternal-fetal & neonatal medicine》2013,26(3):193-197
Objectives.?To determine whether growth velocity parameters derived from routine prenatal ultrasound measurements at first, second and third trimester can identify normal growth at term as well as late-onset growth abnormalities.Material and methods.?Longitudinal study of fetal growth in normal singleton pregnancies with three normal ultrasound examinations and delivered at term. Fetuses were classified into 3 groups (?<?10th percentile, 10–90th percentile, >?90th percentile) based on birth weight. Multiple regression on birth weight classification was used to build up a prediction equation of fetal growth potential (FGP) based on fetal biometry and fetal growth velocity parameters between ultrasound examinations. Best cut-off value for FGP predicting growth restriction and macrosomia were defined.Results.?356 pregnancies were included. Fetal biometry growth velocities between examinations were calculated for all measurements. Using best cut-off values, the estimated sensitivity, specificity and odds ratio were: 60% [44;74], 91%[89;92] and 14.55 [6.30;33.98] and 53% [36;69], 89%[88;91] and 10 [4.27;23.49] for the prediction of growth restriction and macrosomia, respectively.Discussion.?Fetal growth potential can be derived and calculated from standard ultrasound measurements. It can improve identification of these fetuses at risk for late-onset growth abnormalities and their related morbidity. 相似文献