全文获取类型
收费全文 | 116029篇 |
免费 | 5910篇 |
国内免费 | 138篇 |
专业分类
耳鼻咽喉 | 1773篇 |
儿科学 | 5196篇 |
妇产科学 | 3928篇 |
基础医学 | 16052篇 |
口腔科学 | 2835篇 |
临床医学 | 8323篇 |
内科学 | 21980篇 |
皮肤病学 | 3355篇 |
神经病学 | 8976篇 |
特种医学 | 5045篇 |
外国民族医学 | 32篇 |
外科学 | 19020篇 |
综合类 | 1596篇 |
一般理论 | 29篇 |
预防医学 | 5808篇 |
眼科学 | 3392篇 |
药学 | 8043篇 |
中国医学 | 324篇 |
肿瘤学 | 6370篇 |
出版年
2018年 | 887篇 |
2017年 | 773篇 |
2016年 | 1089篇 |
2015年 | 1215篇 |
2014年 | 1598篇 |
2013年 | 2359篇 |
2012年 | 3089篇 |
2011年 | 3138篇 |
2010年 | 1966篇 |
2009年 | 1927篇 |
2008年 | 3245篇 |
2007年 | 3480篇 |
2006年 | 3623篇 |
2005年 | 3739篇 |
2004年 | 3684篇 |
2003年 | 3552篇 |
2002年 | 3504篇 |
2001年 | 7013篇 |
2000年 | 6957篇 |
1999年 | 5859篇 |
1998年 | 1622篇 |
1997年 | 1562篇 |
1996年 | 1334篇 |
1995年 | 1201篇 |
1994年 | 1092篇 |
1993年 | 1120篇 |
1992年 | 3765篇 |
1991年 | 3576篇 |
1990年 | 3561篇 |
1989年 | 3348篇 |
1988年 | 2986篇 |
1987年 | 2894篇 |
1986年 | 2803篇 |
1985年 | 2617篇 |
1984年 | 1943篇 |
1983年 | 1594篇 |
1982年 | 928篇 |
1981年 | 915篇 |
1980年 | 765篇 |
1979年 | 1822篇 |
1978年 | 1346篇 |
1977年 | 1112篇 |
1976年 | 936篇 |
1975年 | 1178篇 |
1974年 | 1214篇 |
1973年 | 1198篇 |
1972年 | 1040篇 |
1971年 | 975篇 |
1970年 | 880篇 |
1969年 | 787篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
A case-control study of squamous cell carcinoma of the upper aerodigestive tract conducted in Heidelberg and Giessen (FRG) provided information on occupational factors in 200 patients and 800 controls (adjusted to sex, age and area of living; 4:1 matched design). The number of subjects exposed to wood dusts, organic chemicals, coal products or to cement was significantly elevated in the tumour group. An increased risk for head and neck cancer was observed after exposition to wood dust (RR = 2,2), organic compounds (RR = 2,4), coal products (RR = 2,7) and especially to cement (RR = 4,4). The cancer risk due to cement exposition showed a positive correlation to the duration of exposition and remained significantly elevated after adjustment for alcohol and tobacco consumption. 相似文献
13.
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
14.
This study aimed at identifying the signal(s) that elicit myositis-induced neuroplastic changes in background activity and responsiveness of spinal neurones. It is based on previous data suggesting that in dorsal horn neurones, responsiveness to peripheral input on one hand and background activity on the other are probably controlled by different mechanisms. In anaesthetized rats, myositis was induced in the gastrocnemius-soleus muscle and the activity of single dorsal horn neurones was recorded in segment L3. Impulse traffic and axoplasmatic transport in dorsal roots L4 and L5 were selectively blocked by lignocaine or vinblastine for various time periods relative to the induction of the myositis. The results show that the main triggering signal for the myositis-induced changes in both responsiveness and background activity is the altered impulse activity in primary afferent fibres. In contrast, 'no axonally transported chemical signal controlling the discharge behaviour of dorsal horn neurones was found. However, the time course of the electrical signals that cause the myositis-induced changes in background activity and responsiveness is different. For changes in responsiveness, a rather narrow time window of 2 h directly after induction of the myositis existed, during which the impulses from the inflamed muscle must reach the spinal cord. Accordingly, to prevent the increase in responsiveness, the electrical input had to be blocked during the first 2 h; a block of the same duration at another time had no effect. The change in background activity seems to be due to a continuous input from the inflamed muscle which adds up over the hours. Therefore, with regard to background activity, blocking the electrical signals is effective at any time, but only a block of long duration has a significant effect. 相似文献
15.
16.
17.
The aqueous, organic, and volatile oil extracts of leaves of Eugenia uniflora Linn. Family Myrtaceae were investigated for antibacterial properties using agar dilution techniques. The aqueous extract was the most active against the organisms compared to the organic and volatile oil extracts. The extracts were found to inhibit Gram positive Staphylococcus aureus and Bacillus subtilis and Gram negative Escherichia coli and Shigella dysentcriae. Pseudomonas aeruginosa, Klebsiella pneumoniac, and Salmonella typhi were not inhibited. 相似文献
18.
19.
20.
Based on a standardized in-vitro method for quantifying the activity of prostaglandin-synthetase by means of coupling malondialdehyde with 2-thiobarbituric acid the possibility of using this method also as ex-vivo technique is described. By this, more favourable prerequisites to pharmacological valuation of the effects of potential antiinflammatory substances exists compared to the application of in-vitro results, only. 相似文献