全文获取类型
收费全文 | 10565篇 |
免费 | 1183篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 74篇 |
儿科学 | 376篇 |
妇产科学 | 358篇 |
基础医学 | 1562篇 |
口腔科学 | 208篇 |
临床医学 | 1163篇 |
内科学 | 2135篇 |
皮肤病学 | 116篇 |
神经病学 | 807篇 |
特种医学 | 450篇 |
外科学 | 1462篇 |
综合类 | 342篇 |
一般理论 | 7篇 |
预防医学 | 1099篇 |
眼科学 | 131篇 |
药学 | 864篇 |
中国医学 | 3篇 |
肿瘤学 | 609篇 |
出版年
2021年 | 142篇 |
2020年 | 100篇 |
2019年 | 153篇 |
2018年 | 164篇 |
2017年 | 138篇 |
2016年 | 139篇 |
2015年 | 182篇 |
2014年 | 268篇 |
2013年 | 373篇 |
2012年 | 488篇 |
2011年 | 518篇 |
2010年 | 304篇 |
2009年 | 282篇 |
2008年 | 431篇 |
2007年 | 449篇 |
2006年 | 437篇 |
2005年 | 422篇 |
2004年 | 400篇 |
2003年 | 380篇 |
2002年 | 375篇 |
2001年 | 325篇 |
2000年 | 338篇 |
1999年 | 303篇 |
1998年 | 161篇 |
1997年 | 152篇 |
1996年 | 169篇 |
1995年 | 142篇 |
1994年 | 119篇 |
1993年 | 134篇 |
1992年 | 231篇 |
1991年 | 254篇 |
1990年 | 224篇 |
1989年 | 207篇 |
1988年 | 228篇 |
1987年 | 238篇 |
1986年 | 213篇 |
1985年 | 217篇 |
1984年 | 161篇 |
1983年 | 150篇 |
1982年 | 97篇 |
1981年 | 94篇 |
1979年 | 108篇 |
1978年 | 89篇 |
1977年 | 85篇 |
1976年 | 80篇 |
1975年 | 80篇 |
1973年 | 89篇 |
1972年 | 85篇 |
1971年 | 77篇 |
1970年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Differences in hip axis and femoral neck length in premenopausal women of Polynesian, Asian and European origin 总被引:4,自引:0,他引:4
There are substantial inter-racial differences in hip fracture incidence. Studies in several different ethnic groups have suggested that differences in the length of the femoral neck may contribute to these. The present study assesses femoral neck and hip axis lengths in three ethnic groups in which it has not been documented previously (Chinese, Indians and Polynesians) and compares these values with those in Europeans. Lengths were measured from dual-energy X-ray absorptiometry scans of the proximal femur in normal premenopausal women (n=225). The Polynesian (1.65 m) and European (1.64 m) women were significantly taller than the two Asian groups (mean height in each, 1.58 m). There were also differences in mean body weight, the Polynesians being the heaviest (76 kg) and the Chinese the lightest (53 kg). Femoral neck lengths were (mean + SD) Chinese 61.5+4.4 mm, Indian 61.5+5.1 mm, Polynesian 68.2+4.3 mm and Europeans 66.0+4.8 mm. Hip axis lengths were Chinese 98.0+5.6 mm, Indian 94.5+5.2 mm, Polynesian 106.4 ± 5.3 mm and European 102.3+5.3 mm. Each of the other groups were significantly different from the Europeans for both variables and, in general, this remained so after height adjustment. These data suggest that shorter femoral necks are common to the major Asian racial groups. However, in contrast to all other ethnic groups studied, Polynesians have longer femoral necks than Europeans and their low incidence of hip fracture is not explicable, therefore, in terms of their femoral neck length. This suggests that either higher bone density or other more subtle differences in proximal femoral geometry must account for the low hip fracture incidence in Polynesians. 相似文献
32.
33.
34.
K. Skradski M. E. Reid PhD M. Mount H.F. Polesky L. Sausais M. Yacob and R. Batts 《Vox sanguinis》1994,66(1):68-71
A discrepancy in duplicate anti-K1 typing in a parentage case led to the discovery of an unusual K1 blood group antigen. Red blood cells from the propositus (JC) express a rare variant of the K1 antigen that is detectable by only 8 of 72 sera containing anti-K1. Absorption and elution studies using reactive anti-K1 confirmed the presence of a K1 antigen. Nonreactive anti-K1 was not absorbed by or eluted from JC's red blood cells. Red cells from 3 of the propositus's siblings also had the variant K1 antigen. The variant antigen exhibited qualitative as well as quantitative differences as compared to normal K1, and we have named it K1var. 相似文献
35.
C1: molecular interactions with activating systems. 总被引:1,自引:0,他引:1
The molecular events controlling complement activation have been gradually unravelled over the past three decades, stimulated by improved isolation procedures and a better understanding of the roles of individual proteins. In this review, Bob Sim and Ken Reid examine the interactions between C1q and its numerous ligands in the initiation of the classical pathway cascade. 相似文献
36.
Effects of intravenous S-9780, an angiotensin-converting enzyme inhibitor, in normotensive subjects 总被引:3,自引:0,他引:3
S-9780 is the active diacid metabolite of the new angiotensin-converting enzyme (ACE) inhibitor perindopril. In a double-blind, randomised, crossover study, the effects of 1, 2, and 4 mg of S-9780 administered intravenously (i.v.) were compared with placebo in eight normotensive subjects. All active doses caused immediate, maximal, and similar inhibition of plasma ACE with 40% inhibition persisting after 48 h. Plasma renin activity was elevated 4 and 8 h after dosing, but no effect on plasma aldosterone, adrenaline or noradrenaline levels was detected. Diastolic blood pressure was lowered by 4 mg of S-9780 until 24 h after dosing. Heart rate did not change. The pharmacokinetics of S-9780 fitted a three-compartment model with a terminal half-life (t1/2) of 31 h. Inhibition of plasma ACE was closely related to observed drug concentration, with 1.8 +/- 0.9 ng/ml (mean +/- S.D.) producing 50% inhibition of the enzyme. S-9780 caused predictable effects on the cardiovascular and renin angiotensin systems. 相似文献
37.
38.
Oxybutynin hydrochloride, an anti-cholinergic/anti-spasmodic agent, was examined for its effect on fertility and peri-post natal development in the rat and its embryotoxic potential in the rat and rabbit. In the rat effects on reproductive performance included a slight increase in the incidence of foetal malformations, extended gestation period and impaired post natal performance of offspring. These findings occurred at dosages clearly associated with maternal toxicity. Oxybutynin hydrochloride did not exert an effect on reproductive processes in the rat at lower dosages or on embryonic and foetal development in the rabbit. 相似文献
39.
Weyers'' ulnar ray/oligodactyly syndrome and the association of midline malformations with ulnar ray defects. 下载免费PDF全文
We describe a two generation family with variable ulnar and radial ray reduction and midline craniofacial abnormalities. The features suggest a diagnosis of Weyers' ulnar ray/oligodactyly syndrome originally described in two isolated cases. Syndromes of ulnar ray reduction are briefly reviewed and the relationship between limb bud and midline development discussed. 相似文献
40.
M M Cortese J Goepp J Almeido-Hill C Barlage T Collins M Hohenboken R Reid M Santosham 《The Pediatric infectious disease journal》1992,11(7):521-525
Eighty-five American Indian children less than 16 years of age with Haemophilus influenzae bacteremia were retrospectively determined to have been treated as outpatients after their initial evaluation. We hoped to determine the proportion that developed new foci, the time interval to this development and whether age or temperature at presentation predicted outcome. Fifty-one (60%) presented with nonfocal findings. Seventy-two (85%) were treated with antibiotics at the initial visit. Although 49 (58%) of the patients were never hospitalized, a new focus was identified in 25 (29%), including 13 (15%) with a final diagnosis of meningitis. The new foci were identified within 6 days of presentation (median, 2 days). An additional 15 (18%) patients had no new focus but were febrile and/or ill at follow-up. All patients with meningitis or a second positive culture were hospitalized at the first follow-up visit. Age and temperature at presentation did not help predict outcome. All patients with H. influenzae bacteremia require prompt reevaluation and close follow-up by an experienced physician. 相似文献