全文获取类型
收费全文 | 2118篇 |
免费 | 167篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 42篇 |
妇产科学 | 50篇 |
基础医学 | 239篇 |
口腔科学 | 52篇 |
临床医学 | 265篇 |
内科学 | 473篇 |
皮肤病学 | 30篇 |
神经病学 | 137篇 |
特种医学 | 92篇 |
外国民族医学 | 1篇 |
外科学 | 276篇 |
综合类 | 27篇 |
一般理论 | 1篇 |
预防医学 | 185篇 |
眼科学 | 57篇 |
药学 | 129篇 |
中国医学 | 2篇 |
肿瘤学 | 208篇 |
出版年
2022年 | 13篇 |
2021年 | 35篇 |
2020年 | 33篇 |
2019年 | 36篇 |
2018年 | 54篇 |
2017年 | 26篇 |
2016年 | 46篇 |
2015年 | 44篇 |
2014年 | 66篇 |
2013年 | 95篇 |
2012年 | 101篇 |
2011年 | 134篇 |
2010年 | 76篇 |
2009年 | 51篇 |
2008年 | 127篇 |
2007年 | 116篇 |
2006年 | 119篇 |
2005年 | 108篇 |
2004年 | 127篇 |
2003年 | 99篇 |
2002年 | 108篇 |
2001年 | 64篇 |
2000年 | 42篇 |
1999年 | 30篇 |
1998年 | 24篇 |
1997年 | 14篇 |
1996年 | 17篇 |
1995年 | 19篇 |
1994年 | 15篇 |
1993年 | 12篇 |
1992年 | 22篇 |
1991年 | 39篇 |
1990年 | 30篇 |
1989年 | 32篇 |
1988年 | 29篇 |
1987年 | 18篇 |
1986年 | 18篇 |
1985年 | 18篇 |
1984年 | 25篇 |
1983年 | 23篇 |
1982年 | 10篇 |
1981年 | 12篇 |
1980年 | 15篇 |
1979年 | 10篇 |
1978年 | 20篇 |
1975年 | 10篇 |
1970年 | 9篇 |
1969年 | 10篇 |
1967年 | 7篇 |
1966年 | 10篇 |
排序方式: 共有2287条查询结果,搜索用时 15 毫秒
1.
I.J. Clifton A.M. Morton N.S. Ambrose D.G. Peckham S.P. Conway 《Journal of cystic fibrosis》2004,3(4):273-275
We report a case of a patient with CF who had a long history of recurrent distal intestinal obstruction syndrome. She had been treated with conventional treatment including gastrografin, n-acetyl cysteine, Klean prep and Picolax. She underwent a modified antegrade continence enema procedure. She currently irrigates her conduit every 2-3 days. She has had no further symptoms of distal intestinal obstruction syndrome. 相似文献
2.
Clifton M. Schor James S. Maxwell Scott B. Stevenson 《Ophthalmic & physiological optics》1994,14(3):279-286
Conjugate gaze is often defined as the equal angle rotation of the two eyes. For fixation at far distances, the optical axes are parallel and conjugacy is defined irrespective of the coordinate system. For nearby or finite fixation distances, the evaluation of conjugacy for many gaze postures depends on the coordinate system used to measure it. For example, if the eye is elevated or depressed and the eye is rotated about a vertical axis, the intersections of lines of sight with a tangent screen will describe either straight lines for arcs depending on whether the vertical axis is fixed with respect to the head or to the eye. Because of the horizontal separation of the two eyes, the binocular fixation of near targets at tertiary positions of gaze will require a vertical vergence component for head-referenced but not eye-referenced measurements. The vertical gaze alignment of three human subjects was measured as they viewed targets placed at secondary and tertiary eye positions at two different distances. Vertical vergence was either held open or closed-loop. The lines of sight were found lo intersect (i.e. vertical gaze was aligned) regardless of target position or viewing condition. 相似文献
3.
Free-feeding and free-drinking patterns of male rats following treatment with opiate kappa agonists.
Three experiments investigated the effects of PD117302 and U50,488H on the patterns of food and water intake by male rats. Experiment 1 demonstrated early dose-related suppression of food and water intake after PD117302 (0, 1.25, 2.5, 5 mg/kg). The initial suppression of drinking was followed by a sustained increase 4-12 h after drug administration. Experiment 2 demonstrated that 2.5 mg/kg PD117302 failed to increase food intake whether given at the beginning of the night (high baseline food intake) or the beginning of the day (low baseline food intake). Experiment 3 showed that 0.5 mg/kg U50,488H significantly enhanced meal size but, at doses of 0.5, 1.0, and 2.0 mg/kg, had no effect on overall food intake. U50,488H also produced delayed, dose-related increases in water intake. The results suggest kappa receptors may have limited importance in modulating ad lib food intake and demonstrate the behavioural characteristics of increased drinking after excessive urine output. 相似文献
4.
5.
Metabolic characteristics of individuals with impaired fasting glucose and/or impaired glucose tolerance. 总被引:24,自引:0,他引:24
With the release of the new 1997 American Diabetes Association diagnostic criteria, a new category was introduced, termed "impaired fasting glucose" (IFG). The metabolic abnormalities of individuals with IFG, compared with those with impaired glucose tolerance (IGT) (World Health Organization criteria), remain to be elucidated. We assessed insulin action (hyperinsulinemic clamp), insulin secretion (25-g intravenous glucose tolerance test), and endogenous glucose output (EGO) (3-(3)H-glucose) in 434 nondiabetic Pima Indians with either normal (NFG; <6.1 mmol/l) or impaired (IFG; 6.1-7.0 mmol/l) fasting glucose and with either normal (NGT; 2-h glucose <7.8 mmol/l) or impaired (IGT; 2-h glucose 7.8-11.1 mmol/l) glucose tolerance: NFG/NGT (n = 307), IFG/NGT (n = 11), NFG/IGT (n = 98), and IFG/IGT (n = 18). Compared with the NFG/NGT group, individuals with IFG/NGT had lower maximal insulin-stimulated glucose disposal (M; -20%, P < 0.01), a lower acute insulin response (AIR) to intravenous glucose (-33%, P < 0.05), and higher EGO (8%, P = 0.055). Individuals with NFG/IGT also had lower M (-21%, P < 0.001) and lower AIR (-8%, P < 0.05), but normal EGO (-1%, NS). Individuals with IFG/IGT showed the most severe abnormalities in M (-27%), AIR (-51%), and EGO (+13%) (all P < 0.001 compared with NFG/NGT). These group differences could be explained by the observation that AIR and EGO, but not M, were more strongly related to the fasting than to the 2-h glucose concentration. Thus, Pima Indians with isolated IFG and isolated IGT show similar impairments in insulin action, but those with isolated IFG have a more pronounced defect in early insulin secretion and, in addition, increased EGO. More severe metabolic abnormalities are present in Pima Indians with combined IFG and IGT. 相似文献
6.
OBJECTIVES: 1) To determine the effect of stimulus train duration (TD) on sensory perception using direct stimulation of somatosensory and visual cortices. 2) To investigate the occurrence of evoked potentials in response to stimulation that is subthreshold for perception. BACKGROUND: Studies of the mechanisms of conscious perception using direct cortical stimulation and recording techniques are rare. The clinical necessity to implant subdural electrode grids in epilepsy patients undergoing evaluation for surgery offers an opportunity to examine the role of stimulus parameters and evoked potentials in conscious perception. METHODS: Subjects included epilepsy patients with grids over somatosensory or occipital cortex. Single pulses (100 microseconds) and stimulus trains were applied to electrodes, and thresholds for perception were found. Evoked potentials were recorded in response to peripheral stimulation at intensities at, above, and below sensory threshold. RESULTS: During cortical stimulation, sensory threshold changed little for stimulus trains of 250 milliseconds and longer, but increased sharply as TD decreased below this level. Primary evoked activity was recorded in response to peripheral stimulations that were subthreshold for conscious perception. CONCLUSIONS: The results confirm a previous report of the effects of stimulus TD on sensory threshold. However, no motor responses occurred following somatosensory stimulation with short trains, as previously reported. The TD threshold pattern was similar in visual cortex. In agreement with the previous report, early components of the primary evoked response were not correlated with conscious sensory awareness. 相似文献
7.
8.
9.