全文获取类型
收费全文 | 1833050篇 |
免费 | 141115篇 |
国内免费 | 2941篇 |
专业分类
耳鼻咽喉 | 25864篇 |
儿科学 | 61271篇 |
妇产科学 | 52099篇 |
基础医学 | 261334篇 |
口腔科学 | 54543篇 |
临床医学 | 159549篇 |
内科学 | 355374篇 |
皮肤病学 | 40641篇 |
神经病学 | 151996篇 |
特种医学 | 75426篇 |
外国民族医学 | 495篇 |
外科学 | 279902篇 |
综合类 | 41117篇 |
现状与发展 | 3篇 |
一般理论 | 608篇 |
预防医学 | 135218篇 |
眼科学 | 42623篇 |
药学 | 137665篇 |
3篇 | |
中国医学 | 3411篇 |
肿瘤学 | 97964篇 |
出版年
2018年 | 19280篇 |
2017年 | 15428篇 |
2016年 | 17907篇 |
2015年 | 19996篇 |
2014年 | 25875篇 |
2013年 | 39723篇 |
2012年 | 54421篇 |
2011年 | 56877篇 |
2010年 | 33255篇 |
2009年 | 30405篇 |
2008年 | 54935篇 |
2007年 | 58223篇 |
2006年 | 58894篇 |
2005年 | 57734篇 |
2004年 | 56374篇 |
2003年 | 54317篇 |
2002年 | 53218篇 |
2001年 | 83173篇 |
2000年 | 86822篇 |
1999年 | 72440篇 |
1998年 | 19823篇 |
1997年 | 18011篇 |
1996年 | 17674篇 |
1995年 | 17141篇 |
1994年 | 16148篇 |
1993年 | 15225篇 |
1992年 | 57576篇 |
1991年 | 55810篇 |
1990年 | 54527篇 |
1989年 | 52665篇 |
1988年 | 48819篇 |
1987年 | 48250篇 |
1986年 | 45804篇 |
1985年 | 44456篇 |
1984年 | 33430篇 |
1983年 | 28696篇 |
1982年 | 17080篇 |
1981年 | 15301篇 |
1979年 | 31775篇 |
1978年 | 22165篇 |
1977年 | 18741篇 |
1976年 | 17551篇 |
1975年 | 18690篇 |
1974年 | 22653篇 |
1973年 | 21648篇 |
1972年 | 19887篇 |
1971年 | 18759篇 |
1970年 | 17182篇 |
1969年 | 16090篇 |
1968年 | 14781篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
181.
182.
183.
This study surveyed male and female athletes from 22 midwesterncolleges and universities regarding behaviors and attitudesassociated with anorexia nervosa and bulimia nervosa. The responserate was 66% (N= 695) and the findings indicated that the bodyimage of some athletes may be distorted; one-seventh perceivedthemselves as fat even though they were not. Many athletes seemedpreoccupied with food and weight; almost one-third reportedroutinely thinking about food and weight and more than one-thirdreported dramatic annual weight fluctuations (9 lb or greater)related to bingeing and fasting. Athletes also did not feelin control when they ate and their habits related to food consumptionappeared to be extreme; one-tenth reported a lack of controlwhen they ate, more than one-third binged, one-twentieth ateuntil they were physically ill, and a similar proportion preferrednot to eat in the presence of others. In addition, it was foundthat as many men as women athletes reported these perceptionsbut significant sex differences were noted for specific items.It was suggested that behaviors and attitudes be viewed on acontinuum with normals at one end, eating disordered individuals at the other end,and college athletes in between. Health education that focuseson behaviors and attitudes as symptoms of eating disorders wasrecommended for athletes and those working closely with athletes.Future research was suggested to determine reasons for the undesirablebehaviors and attitudes and to study the onset, development,long-term effects and whether these behaviors and attitudeslead to an eating disorder. 相似文献
184.
185.
Use of algal fluorescence for determination of phytotoxicity of heavy metals and pesticides as environmental pollutants 总被引:3,自引:0,他引:3
The phytotoxicity of heavy metals and pesticides was studied by using the fluorescence induction from the alga Dunaliella tertiolecta. The complementary area calculated from the variable fluorescence induction was used as a direct parameter to estimate phytotoxicity. The value of this parameter was affected when algae were treated with different concentrations of mercury, copper, atrazine, DCMU, Dutox, and Soilgard. The toxic effect of these pollutants was estimated by monitoring the decrease in the complementary area, which reflects photosystem II photochemistry. Further, the authors have demonstrated the advantage of using the complementary area as a parameter of phytotoxicity over using variable fluorescence yield. The complementary area of algal fluorescence can be used as a simple and sensitive parameter in the estimation of the phytotoxicity of polluted water. 相似文献
186.
187.
Eight-eight female weanling Sprague-Dawley rats were fed diets containing either 650 or 150 mg magnesium/kg diet and 7.0 or 3.5 mg pyridoxine-HCl/kg diet, in a 2 x 2 factorial arrangement, during growth, gestation, and lactation. The objective of the study was to determine whether concurrent dietary deficiencies of magnesium and pyridoxine were synergistic, additive, or antagonistic with regards to effects on reproductive performance, growth, and development of offspring, and tissue content of magnesium and calcium. Body weight of dams and pups was not different between groups until day 9 of lactation, at which point those animals in either low magnesium group weighed less than the other. Litter size and birth weight were not different. Development, as measured by timing of unfolding of the external ear, opening of both eyes, and clinical emergence of incisors, was delayed in pups from litters in the low magnesium groups. A synergistic effect on delay of onset of ear unfolding by deficiency of both magnesium and pyridoxine was observed. Calcium content of heart and kidney from dams was increased in the low magnesium groups. Renal calcium was not further increased by the level of pyridoxine deficiency in this study. The calcium to magnesium ratio in heart from pups was higher in those from litters in the low magnesium and pyridoxine group than in the others. Results indicate that simultaneous deficiencies of magnesium and pyridoxine may impair function synergistically. Because these two nutrients are often reported to be presented in inadequate amounts in diets of women in their reproductive years, the potential exists for impaired reproductive success. 相似文献
188.
189.
R B Birrer 《The Journal of the American Board of Family Practice / American Board of Family Practice》1988,1(4):274-281
In transmitting the body's weight, the ankle is subject to frequent static and dynamic injury due to concentrated stresses during standing and movement. The frequency of athletic ankle injuries ranges from 10 to 90 percent, with the highest rate occurring in basketball players. There is prolonged disability and recurrent instability for months to years for 25 to 40 per cent of these patients. Because most of this trauma is handled by primary care physicians, this review presents the mechanism of injury, relevant anatomy, physical examination, and appropriate therapeutic intervention in the acute and rehabilitative phases. 相似文献
190.