全文获取类型
收费全文 | 1183268篇 |
免费 | 77196篇 |
国内免费 | 1559篇 |
专业分类
耳鼻咽喉 | 16661篇 |
儿科学 | 39533篇 |
妇产科学 | 32230篇 |
基础医学 | 167865篇 |
口腔科学 | 32358篇 |
临床医学 | 102538篇 |
内科学 | 224377篇 |
皮肤病学 | 27409篇 |
神经病学 | 89439篇 |
特种医学 | 47479篇 |
外国民族医学 | 232篇 |
外科学 | 180726篇 |
综合类 | 23462篇 |
现状与发展 | 1篇 |
一般理论 | 300篇 |
预防医学 | 80153篇 |
眼科学 | 28283篇 |
药学 | 93814篇 |
7篇 | |
中国医学 | 3162篇 |
肿瘤学 | 71994篇 |
出版年
2021年 | 8710篇 |
2019年 | 8660篇 |
2018年 | 12534篇 |
2017年 | 9881篇 |
2016年 | 11395篇 |
2015年 | 12653篇 |
2014年 | 17222篇 |
2013年 | 24969篇 |
2012年 | 34156篇 |
2011年 | 35987篇 |
2010年 | 21157篇 |
2009年 | 19861篇 |
2008年 | 33275篇 |
2007年 | 35691篇 |
2006年 | 36396篇 |
2005年 | 34687篇 |
2004年 | 33263篇 |
2003年 | 31873篇 |
2002年 | 30767篇 |
2001年 | 65594篇 |
2000年 | 67041篇 |
1999年 | 55573篇 |
1998年 | 13822篇 |
1997年 | 12294篇 |
1996年 | 12115篇 |
1995年 | 11340篇 |
1994年 | 10273篇 |
1993年 | 9786篇 |
1992年 | 40909篇 |
1991年 | 39254篇 |
1990年 | 38692篇 |
1989年 | 37092篇 |
1988年 | 33369篇 |
1987年 | 32475篇 |
1986年 | 30602篇 |
1985年 | 28700篇 |
1984年 | 20849篇 |
1983年 | 17483篇 |
1982年 | 9635篇 |
1979年 | 18580篇 |
1978年 | 12563篇 |
1977年 | 11184篇 |
1976年 | 9659篇 |
1975年 | 11090篇 |
1974年 | 12719篇 |
1973年 | 12313篇 |
1972年 | 11681篇 |
1971年 | 10937篇 |
1970年 | 10021篇 |
1969年 | 9654篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
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
94.
95.
A rotating contact lens holder for the three-mirror Goldmann lens permits circular examination of the fundus or chamber angle without having to change the position of the fingers on the edge of the lens. The contact lens holder consists of an outer polygonal ring hold by the thumber and index finger. An inner rotating ring holds the contact lens. Continuous rotation of the contact lens is performed with the free middle Finger. This device permits circular examination of the retina without interruption of fixation. The instrument improves not only the speed but also the reliability of the examination. 相似文献
96.
K A Burkman R W Gaines S R Kashani R D Smith 《Archives of physical medicine and rehabilitation》1988,69(2):132-134
Herpes zoster probably occurs more often than generally thought. Since it produces a radicular distribution of pain, it should be included in the differential diagnosis of radiculopathy. A case is presented in which evaluating the radicular low back pain before the characteristic rash appears was misleading. Careful history-taking concerning the exact nature of the pain and sensory changes is needed to differentiate between zoster and radiculopathy, if no rash is evident. 相似文献
97.
K Brown 《Environmental health perspectives》1996,104(3):276-278
98.
The rate of ethanol elimination and blood acetate concentrationsafter a peroral dose of alcohol were measured in eight asthmaticpatients receiving high-dose corticosteroid, sustained releasetheophylline and beta-2-sympathicomimetic treatment and in eightnonalcoholic, healthy controls. Mean ethanol elimination rate(ER) and mean blood acetate concentration (AC) were significantly(P<0.01) higher in asthmatics (ER=134.8 ± 12.9 mg/kg/hr,AC = 1.13± 0.25 mM) than in controls (ER = 100.2 ±12.3 mg/kg/hr, AC = 0.64 ± 0.10 mM). In the asthmaticsthere was a significant negative correlation between the ageand the rate of ethanol elimination (r = 0.890, P <0.01); in the control group, however, this correlation was oflower degree (r = 0.423) and did not achieve statisticalsignificance. Enhanced ethanol metabolism in asthmatics is possiblydue to the effect of drugs. Our results suggest that ethanolelimination rate is increased in asthmatics receiving medicationand that the effect is most significant in younger age groups. 相似文献
99.
100.
SRIVASTAVA Z. I.; MATHUR N.; RASTOGI S. K.; GUPTA B. N. 《Occupational medicine (Oxford, England)》1988,38(4):134-136
Eighty-nine cases of chronic bronchitis were matched against167 asymptomatic controls from the glass bangle industry ofFirozabad. Factors of age, social status, smoking habit andduration of exposure were studied. Duration of exposure wasfound to be a factor contributing significantly to the causationof disease.
Requests for reprints should be addressed to: Dr B. N. Gupta, Division of Epidemilogy, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow P.O. Box 80, 226001, India 相似文献