全文获取类型
收费全文 | 5703篇 |
免费 | 337篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 213篇 |
妇产科学 | 32篇 |
基础医学 | 799篇 |
口腔科学 | 63篇 |
临床医学 | 169篇 |
内科学 | 566篇 |
皮肤病学 | 6篇 |
神经病学 | 480篇 |
特种医学 | 57篇 |
外科学 | 212篇 |
综合类 | 153篇 |
预防医学 | 2465篇 |
眼科学 | 6篇 |
药学 | 678篇 |
中国医学 | 30篇 |
肿瘤学 | 137篇 |
出版年
2023年 | 78篇 |
2022年 | 172篇 |
2021年 | 406篇 |
2020年 | 211篇 |
2019年 | 199篇 |
2018年 | 172篇 |
2017年 | 136篇 |
2016年 | 150篇 |
2015年 | 198篇 |
2014年 | 261篇 |
2013年 | 469篇 |
2012年 | 201篇 |
2011年 | 293篇 |
2010年 | 202篇 |
2009年 | 225篇 |
2008年 | 244篇 |
2007年 | 185篇 |
2006年 | 173篇 |
2005年 | 148篇 |
2004年 | 138篇 |
2003年 | 120篇 |
2002年 | 96篇 |
2001年 | 78篇 |
2000年 | 79篇 |
1999年 | 68篇 |
1998年 | 69篇 |
1997年 | 66篇 |
1996年 | 49篇 |
1995年 | 58篇 |
1994年 | 35篇 |
1993年 | 35篇 |
1992年 | 59篇 |
1991年 | 54篇 |
1990年 | 51篇 |
1989年 | 42篇 |
1988年 | 57篇 |
1987年 | 33篇 |
1986年 | 25篇 |
1985年 | 85篇 |
1984年 | 88篇 |
1983年 | 67篇 |
1982年 | 75篇 |
1981年 | 54篇 |
1980年 | 69篇 |
1979年 | 63篇 |
1978年 | 50篇 |
1977年 | 37篇 |
1976年 | 43篇 |
1975年 | 37篇 |
1974年 | 26篇 |
排序方式: 共有6070条查询结果,搜索用时 31 毫秒
51.
Consumption of excess fat increases risk for many health problems and diseases. In the present study, 188 undergraduate students were studied to understand self-perceptions of dietary-fat intake and the impact of those perceptions. Findings indicated that the majority of participants had inaccurate perceptions about the amount of fat in their diets. Further, compared to people who overestimated dietary-fat intake, people who underestimated fat intake had lower perceived risk of cancer, had lower intentions to change, and demonstrated less knowledge about the dietary-fat content of many foods. Findings suggest that this unrealistic underestimation of fat intake is a cognitive barrier to dietary change and people who underestimate dietary fat intake may require more intensive intervention to change their diets. 相似文献
52.
The intracerebroventricular administration of the 17 amino acid peptide nociceptin/orphanin FQ (N/OFQ), the endogenous ligand of the NOP receptor (previously referred to as ORL-1 or OP4 receptor), reduces voluntary 10% ethanol intake in genetically selected Marchigian Sardinian alcohol-preferring (msP) rats. Studies aimed at the pharmacological characterization of the receptor, which mediates the effect, have shown that the C-terminal 13 amino acid sequence is crucial for activity and that the selective NOP receptor antagonist [Nphe(1)]N/OFQ(1-13)NH(2) blocks the effect of N/OFQ on ethanol drinking. In place conditioning studies, N/OFQ abolishes the conditioned place preference (CPP) induced by ethanol in msP rats, or by morphine in nonselected Wistar rats; these findings suggest that N/OFQ is able to abolish the rewarding properties of ethanol and morphine. Moreover, N/OFQ inhibits reinstatement of alcohol-seeking behavior induced to electric footshock stress, as well as reinstatement of alcohol-seeking behavior induced by ethanol-paired cues. Together, these findings suggest that N/OFQ and its receptor may represent an interesting target for pharmacological treatment of alcohol abuse. 相似文献
53.
Donald A. Czech 《Physiology & behavior》1982,29(6):1179-1181
An casuy constructed and inexpensive drop-sensing drinkometer is described, which incorporates an integrated circuit photodetector. It provides a reliable and convenient means of automatically monitoring fluid intake in a number of experimental situations. The animal is undisturbed and isolated from the electrical system components. 相似文献
54.
Two experiments, each using approximately 30 male and 30 female hooded rats, examined the effects of electroconvulsive shock (ECS) on water intake as a function of the water deprivation state of the animal and food intake and body weight as a function of food deprivation state. In Experiment 1, half the animals were subjected to water deprivation prior to ECS or sham ECS, and the other half were watered ad lib; in Experiment 2, food deprivation was the pre-ECS manipulation. As predicted, ECS produced a decrease in water intake in the ad lib watered animals but not in the deprived ones. A similar treatment by deprivation interaction was not found for food intake or body weight. In the males, food intake was decreased for one day by the treatment but recovered to a normal level two days following ECS; however, such an effect of ECS on food intake did not occur in the females. Since food and water intake was not differentially affected by ECS and sham ECS in deprived animals, previous cautions regarding ECS effects on motivational states may not be germane to many studies using appetitive conditioning paradigms. 相似文献
55.
Body weight and food intake of lean and obese, male and female Osborne-Mendel rats following treadmill exercise were compared. Rats were assigned, separately by sex, to one of three diet groups; Group 1 was fed a low fat (10%) diet throughout the study, Group 2 was fed a high fat (55%) diet for 16 weeks and then switched to the low fat diet 1 week prior to exercise, and Group 3 was fed the high fat diet throughout the study. To control for differences in work output between the leanest and heaviest animals, exercise intensity was adjusted across groups such that all exercised rats had equivalent energy expenditure. After a 3 day training period, the exercise was successively increased over 8 days until a work output of 374.9J was reached. Relative to their respective controls, obese exercised males showed a reduction in body weight but no change in food intake. In contrast, exercised females showed no change in body weight or food intake, regardless of dietary condition. 相似文献
56.
Four human subjects were fed ad lib with a bland diet for a period of 3 weeks. Their body weight decreased by 3.13 kg during this period. It was observed that the shift of the palatability response to sucrose solutions induced by a gastric glucose load (alliesthesia) was not affected by such a reduction of body weight. This result was compared to a previous experiment showing a decreased alliesthesia after a body weight loss due to the restriction of a palatable diet. These results confirm the role of the palatability of the diet on the maintenance of a body weight level and provide evidence for an interaction between the two factors in determining the oral satiation process. 相似文献
57.
Prof. H. Hofmann Dr. C. Bothge Dr. S. Haselwarter Prof. L. Heinemann Dr. W. Barth Dr. E. Schüler Prof. U. Laaser Dr. M. Siegel Prof. F. C. Luft Die Intersalt-Forschungsgruppe aus BRD und DDR 《Journal of molecular medicine (Berlin, Germany)》1990,68(13):655-663
Summary The relationships between body mass index (BMI) and age, alcohol consumption, 24-hr urinary electrolyte excretion, and BP were studied in 588 subjects from three German centers participating inIntersalt, a highly standardized, previously reported protocol. Men and women aged 20–59 were sampled in Bernried, FRG; Cottbus, GDR; and Heidelberg, FRG. The subjects from the three centers did not differ in BMI, level of education, physical activity, cigarette- or alcohol-consumption patterns, or urinary Cl excretion. Mean Na excretion was 167, 147, and 172 mmol/24 hr in Bernried, Cottbus, and Heidelberg, while mean K excretion was 72, 55, and 73 mmol/24 hr, respectively. The excretion of these electrolytes was significantly lower in Cottbus than in Bernried or Heidelberg. BMI increased progressively in men with age; in women BMI plateaued until the 5th decade, after which it increased to equal that of men. In individual centers, the excretion of electrolytes was correlated with BML Sodium and chloride excretion were highly correlated. The data from each individual center were fitted to a multiple regression model. Age, BMI, sex, and alcohol consumption entered the model. 相似文献
58.
M G Tordoff 《Physiology & behavior》1985,35(3):455-463
Rats that were neonatally sympathectomized with guanethidine (GUA) and given access to a four-component supermarket diet (SD) when either adolescent or adult gained weight at the same rate as controls. Adrenodemedullation (MDL) of adults, either alone or in combination with GUA treatment, also failed to influence the development of dietary obesity. Neonatal sympathectomy induced small changes in caloric consumption and diet preferences. These results question the notion that the sympathetic nervous system (SNS) is an essential contributor to the control of body weight and the development of dietary obesity. 相似文献
59.
V. Candas J. P. Libert G. Brandenberger J. C. Sagot C. Amoros J. M. Kahn 《European journal of applied physiology》1986,55(2):113-122
Summary Five young unacclimatised subjects were exposed for 4 h at 34 C (10 C dew-point temperature and 0.6 m · s–1 air velocity), while exercising on a bicycle ergometer: 25 min work — 5 min rest cycles for 2 hours followed by 20 min work — 10 min rest cycles for two further hours. 5 experimental sessions were carried out: one without rehydration (NO FLUID) resulting in 3.1% mean loss of body weight ( Mb), and four sessions with 20 C fluid ingestion of spring water (WATER), hypotonic (HYPO), isotonic (ISO) and hypertonic (HYPER) solutions to study the effects of fluid osmolarity on rehydration. Mean final rehydration (±SE) after fluid intake was 82.2% (±1.2). Heart rate was higher in NO FLUID while no difference among conditions was found in either Mb or hourly sweat rates. Sweating sensitivity was lowest in the dehydration condition, and highest in the WATER one. Modifications in plasma volume and osmolarity demonstrated that NO FLUID induced hyperosmotic hypovolemia, ISO rehydration rapidly led to plasma isoosmotic hypervolemia, while WATER led to slightly hypoosmotic normovolemia.It is concluded that adequate rehydration through ingestion of isotonic electrolyte-sucrose solution, although in quantities much smaller than evaporative heat loss, rapidly restored and expanded plasma volume. While osmolarity influenced sweating sensitivity, the plasma volume changes ( PV) within the range –6% PV+4% had little effect on temperature adjustments in our conditions. 相似文献
60.
Four adult female Sprague-Dawley rats, maintained on an ad lib feeding schedule were deprived for either 0, 0.5, 1, 2, 4, 6, or 8 hours during the dark phase of the day-night cycle. It was found that the latency to initiate the first meal following the deprivation was independent of the previous deprivation interval. The animals were found to overcompensate for the periods without food by eating a large initial meal that increased proportionately in size with the duration of food restriction. Furthermore, the animals continued to overeat throughout the day. This deprivation-induced overeating by the animals resulted in an overcompensation in total food consumption that was 21–56% greater than on control days. The role of food intake as a regulator of body weight is discussed. 相似文献