全文获取类型
收费全文 | 3931799篇 |
免费 | 309218篇 |
国内免费 | 14516篇 |
专业分类
耳鼻咽喉 | 53777篇 |
儿科学 | 124061篇 |
妇产科学 | 101736篇 |
基础医学 | 610340篇 |
口腔科学 | 107570篇 |
临床医学 | 355979篇 |
内科学 | 697363篇 |
皮肤病学 | 102085篇 |
神经病学 | 328549篇 |
特种医学 | 155210篇 |
外国民族医学 | 519篇 |
外科学 | 601550篇 |
综合类 | 116512篇 |
现状与发展 | 23篇 |
一般理论 | 2432篇 |
预防医学 | 324449篇 |
眼科学 | 91611篇 |
药学 | 277471篇 |
27篇 | |
中国医学 | 11160篇 |
肿瘤学 | 193109篇 |
出版年
2021年 | 55680篇 |
2020年 | 35492篇 |
2019年 | 58436篇 |
2018年 | 72712篇 |
2017年 | 55640篇 |
2016年 | 61600篇 |
2015年 | 75182篇 |
2014年 | 109591篇 |
2013年 | 175050篇 |
2012年 | 105921篇 |
2011年 | 108551篇 |
2010年 | 121215篇 |
2009年 | 124079篇 |
2008年 | 94863篇 |
2007年 | 99833篇 |
2006年 | 109697篇 |
2005年 | 104504篇 |
2004年 | 106106篇 |
2003年 | 96650篇 |
2002年 | 85995篇 |
2001年 | 139899篇 |
2000年 | 134201篇 |
1999年 | 126509篇 |
1998年 | 68981篇 |
1997年 | 65623篇 |
1996年 | 63470篇 |
1995年 | 59018篇 |
1994年 | 53023篇 |
1993年 | 49260篇 |
1992年 | 90883篇 |
1991年 | 86927篇 |
1990年 | 83807篇 |
1989年 | 82081篇 |
1988年 | 75131篇 |
1987年 | 73915篇 |
1986年 | 69795篇 |
1985年 | 68798篇 |
1984年 | 59111篇 |
1983年 | 52910篇 |
1982年 | 45189篇 |
1981年 | 42186篇 |
1980年 | 39752篇 |
1979年 | 49955篇 |
1978年 | 41476篇 |
1977年 | 37859篇 |
1976年 | 34498篇 |
1975年 | 34068篇 |
1974年 | 36315篇 |
1973年 | 35096篇 |
1972年 | 32768篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Prevention of Bone Loss by Clodronate in Early Postmenopausal Women with Vertebral Osteopenia: A Dose-Finding Study 总被引:1,自引:0,他引:1
M. J. V?lim?ki K. Laitinen K. Laitinen A. Patronen H. Puolijoki H. Puolijoki J. Sepp?nen L. Pylkk?nenand the Probone Study Group 《Osteoporosis international》2002,13(12):937-947
This double-masked, placebo-controlled study was undertaken to determine the efficacy and safety of oral clodronate in the
prevention of bone loss in early postmenopausal women with vertebral osteopenia. Altogether 610 women with a mean age of 53
years were recruited for the study. They were 1–5 years postmenopausal and their lumbar spine bone mineral density (BMD) was
at least 1 standard deviation below the mean of premenopausal women (T-score ≤−1). The subjects were randomized into five study groups to receive either placebo, clodronate 65 mg, 400 mg or 800
mg daily, or intermittent clodronate in 3 month cycles with 400 mg daily for 15 days followed with no treatment for 75 days
for 3 years. One hundred and eighty-seven of 509 women who completed the primary study continued in the extension study of
2 years in which previous placebo users were switched to clodronate 800 mg daily, while previous users of 400 mg or 800 mg
of clodronate used either placebo or 800 mg of clodronate daily. In the primary study clodronate was administered in the evening,
and in the extension 1 h before breakfast on an empty stomach. In the primary study mean changes in lumbar spine BMD were
−3.4% in the placebo group and +0.4% in 800 mg clodronate group [difference between groups at 3 years 3.8% (95% CI 2.7% to
4.9%, p<0.0001)], and in the trochanter area BMD −1.1% in the placebo group, and + 0.4% in the 800 mg clodronate group [difference
between groups at 3 years 1.5% (95% CI 0.05% to 2.9%)]. During the extension study mean changes in lumbar spine BMD were +1.5%
in the clodronate group and −0.2 % in the placebo group [difference between groups 1.7% (CI 0.4% to 3.0%, p = 0.010)] and in trochanter BMD were +2.5% in the clodronate group and no change in the placebo group [difference between
groups 2.1% (CI 0.3% to 3.9%, p = 0.007)]. No statistically significant differences between the placebo and 800 mg clodronate groups were found in the femoral
neck BMD. In the primary study the urinary excretion of type I collagen aminoterminal telopeptide (NTX) decreased by 44% (p<0.0001 compared with placebo) and that of deoxypyridinoline by 18% (p<0.0001) in the clodronate 800 mg group. In the extension study urinary NTX decreased by 51% (p<0.0001) in those who were switched to 800 mg of clodronate and increased by 67% (p<0.0001) in those who stopped using that dose. There was no difference in the frequency of gastrointestinal complaints between
clodronate- and placebo-treated patients in the primary study, but they were more common among women who received clodronate
in the extension phase. Clodronate in daily doses of 400–800 mg caused a slight elevation of aminotransferase levels, usually
within the reference range. In bone biopsies no defect in mineralization was found. In conclusion, clodronate in a daily dose
of 800 mg prevents early postmenopausal bone loss at the sites of the skeleton in which cancellous bone predominates. It effectively
reduces bone resorption and bone turnover rate. Antifracture efficacy of clodronate remains to be established by prospective,
placebo-controlled trials.
Received: 4 March 2002 / Accepted: 9 July 2002 相似文献
992.
Abra R. M. Hunt C. Anthony Fu K. K. Peters J. H. 《Cancer chemotherapy and pharmacology》1983,11(2):98-101
Cancer Chemotherapy and Pharmacology - Addition of solid doxorubicin or solutions to pre-formed liposomes proved to be the optimal method for incorporating the drug into liposomes whilst... 相似文献
993.
994.
995.
996.
Summary In cases where a reconstruction of defects in the larynx, oral cavity, the pharynx or in the ear region has been performed using skin flaps, a temporary fistula is formed at the point of entry.This fistula can be closed later after the flap has taken and the flap pedicle dissected.We would like to demonstrate with some examples that with the use of deepithelisation it is possible to achieve a primary wound closure. This way no temporary fistula results and additional surgery is avoided in many cases.Furthermore flap deepithelisation offers a way to bring good vascularised tissue under the skin and cover subcutaneous defects, for example those after radiotherapy.
Die Veröffentlichung des Manuskripts soll in Laryngol Rhinol Otol (Stuttg) erfolgen 相似文献
Die Veröffentlichung des Manuskripts soll in Laryngol Rhinol Otol (Stuttg) erfolgen 相似文献
997.
Meir Steiner Richard J. Katz Giulio Baldrighi Bernard J. Carroll 《Psychoneuroendocrinology》1981,6(1):81-90
(1) The estrous cycle in the rat may be used to study recurrent changes in motor behaviors and motivation which are strongly related to cyclic hormonal and CNS changes. (2) The peak in motivated behaviors occurs during a sharply defined period on the night between proestrus and estrus and is evident in facilitated wheel-running, lordosis, and intracranial self-stimulation. (3) Behaviors without a clearly motivated character do not show an estrous cyclicity. (4) The estrous cyclic variation in intracranial self-stimulation was observed at a specific locus — the pars campacta of the substantia nigra. (5) A neurochemical link between sexually motivated behavior, wheel running and intracranial self-stimulation is suggested. This link is in part dopaminergic but is probably also activated by many other systems. 相似文献
998.
999.
1000.