全文获取类型
收费全文 | 1727篇 |
免费 | 112篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 150篇 |
妇产科学 | 19篇 |
基础医学 | 158篇 |
口腔科学 | 70篇 |
临床医学 | 161篇 |
内科学 | 372篇 |
皮肤病学 | 39篇 |
神经病学 | 28篇 |
特种医学 | 351篇 |
外科学 | 134篇 |
综合类 | 35篇 |
预防医学 | 85篇 |
眼科学 | 23篇 |
药学 | 100篇 |
1篇 | |
中国医学 | 1篇 |
肿瘤学 | 136篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 16篇 |
2020年 | 10篇 |
2019年 | 24篇 |
2018年 | 32篇 |
2017年 | 23篇 |
2016年 | 25篇 |
2015年 | 34篇 |
2014年 | 31篇 |
2013年 | 58篇 |
2012年 | 32篇 |
2011年 | 30篇 |
2010年 | 48篇 |
2009年 | 90篇 |
2008年 | 30篇 |
2007年 | 51篇 |
2006年 | 45篇 |
2005年 | 41篇 |
2004年 | 28篇 |
2003年 | 38篇 |
2002年 | 30篇 |
2001年 | 26篇 |
2000年 | 31篇 |
1999年 | 41篇 |
1998年 | 105篇 |
1997年 | 119篇 |
1996年 | 113篇 |
1995年 | 77篇 |
1994年 | 82篇 |
1993年 | 98篇 |
1992年 | 23篇 |
1991年 | 18篇 |
1990年 | 21篇 |
1989年 | 46篇 |
1988年 | 43篇 |
1987年 | 31篇 |
1986年 | 36篇 |
1985年 | 33篇 |
1984年 | 24篇 |
1983年 | 17篇 |
1982年 | 20篇 |
1981年 | 35篇 |
1980年 | 22篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 21篇 |
1976年 | 19篇 |
1975年 | 6篇 |
1970年 | 4篇 |
排序方式: 共有1865条查询结果,搜索用时 0 毫秒
1.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight. 相似文献
2.
CM Reid M. Nelson P. Beckinsale P. Ryan LMH Wing LJ Beilin MA Brown GLR Jennings CI Johnston J. Marley JJ McNeil TO Morgan J. Shaw ID Steven MJ West 《Clinical and experimental pharmacology & physiology》1997,24(5):370-373
1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial. 相似文献
3.
4.
5.
6.
We have developed RIAs using antisera directed against the cryptic peptide of the GnRH precursor (termed GnRH-associated peptide, GAP) and have used these together with a GnRH assay to characterize proGnRH-derived peptides in rat hypothalamic extracts. On Sephadex chromatography we have identified three molecular forms of GAP-like immunoreactivity (GAP-LI), in addition to the GnRH decapeptide. The largest of these forms is an 8.0-kilodalton (kD) GAP-LI which appears to be the complete proGnRH peptide. The second is a 6.5-kD GAP-LI, and is similar to the complete cryptic peptide (i.e. proGnRH14-69 or GAP1.56). The third peptide is a 2.5 kD C-terminal fragment of the cryptic peptide, representing a processed form of GAP. In whole hypothalamic extracts from normal rats the 8.0-kD form was the major form, comprising 60-70% of the total GAP-LI. All three forms were present in three distinct areas of the rat hypothalamus, namely median eminence (ME), anterior and mid-hypothalamus. However in the ME the proportion of 8.0-kD GAP-LI was significantly reduced and the proportion of 6.5-kD GAP-LI significantly increased compared to anterior and mid-hypothalamic samples (p less than 0.05). In whole hypothalamic extracts from pregnant and lactating rats the total content of proGnRH-derived peptides was reduced but the relative proportions of these peptides were not significantly changed from normal female rats. However, in postlactating rats, 2 weeks after removal of pups, the total levels of GAP-LI were unchanged compared to normals, but the percentage of 8.0-kD GAP-LI was significantly decreased and the percentage of 2.5-kD GAP-LI significantly increased compared to normals (p less than 0.05), suggesting that proGnRH may undergo additional processing dependent on physiological condition. In fetal and neonatal rats the proportion of the 6.5-kD peptide was increased and that of the 8.0-kD peptide decreased compared to adults, and this change became less significant with increasing age. In ovariectomized rats the proportion of 6.5-kD GAP-LI was increased and that of 8.0-kD GAP-LI decreased; this change was partially reversed with steroid treatment. Both the 6.5 and 2.5-kD forms were released by high K+ stimulation of neonatal hypothalamic cells in culture. These results indicate that there is differential processing of the proGnRH precursor within the hypothalamus and in altered physiological states. 相似文献
7.
8.
A comprehensive anatomic and radiographic analysis of the peribursal fat plane in 12 cadavers confirmed that the fat plane seen on radiographs represents extrasynovial fat lining the subacromial bursa and documented the anatomic relations of the bursa. A three-part retrospective clinical evaluation of rotator cuff tears, calcific tendinitis, and rheumatoid arthritis was performed. Two osteoradiologists blindly graded the appearance of the peribursal fat plane with the shoulder in external versus internal rotation in 21 patients with arthrographically intact rotator cuffs and 21 patients with disrupted rotator cuffs. The peribursal fat plane was seen better with disrupted rotator cuffs. The peribursal fat plane was seen better with the shoulder in internal rotation and was seen in 60% of control subjects but only 21% of patients with rotator cuff tears. Partial or complete obliteration of this fat plane is a sensitive (79%) but less specific (60%) indicator of rotator cuff tears. Obliteration of the peribursal fat plane by inflammatory processes in adjacent tissues, including calcific tendinitis and rheumatoid arthritis, occurred with a high frequency. 相似文献
9.
Rosenberg ZS; Jahss MH; Noto AM; Shereff MJ; Cheung Y; Frey CC; Norman A 《Radiology》1988,167(2):489-493
Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture. 相似文献
10.
LN Weinberger MJ Zirwas JC English III 《Journal of the European Academy of Dermatology and Venereology》2007,21(2):156-162
Male genital oedema can be defined as swelling or the appearance of swelling of the scrotum and/or the penile shaft and prepuce. Despite the various causes of genital oedema reported in the published work, a concise approach to the evaluation and management has not been sufficiently addressed. 相似文献