全文获取类型
收费全文 | 213682篇 |
免费 | 14146篇 |
国内免费 | 1248篇 |
专业分类
耳鼻咽喉 | 2336篇 |
儿科学 | 6414篇 |
妇产科学 | 4304篇 |
基础医学 | 28612篇 |
口腔科学 | 4265篇 |
临床医学 | 19521篇 |
内科学 | 45943篇 |
皮肤病学 | 3406篇 |
神经病学 | 20354篇 |
特种医学 | 7376篇 |
外国民族医学 | 24篇 |
外科学 | 30511篇 |
综合类 | 3285篇 |
现状与发展 | 1篇 |
一般理论 | 200篇 |
预防医学 | 15982篇 |
眼科学 | 4766篇 |
药学 | 16176篇 |
4篇 | |
中国医学 | 782篇 |
肿瘤学 | 14814篇 |
出版年
2023年 | 979篇 |
2022年 | 1970篇 |
2021年 | 3998篇 |
2020年 | 2479篇 |
2019年 | 3910篇 |
2018年 | 4697篇 |
2017年 | 3501篇 |
2016年 | 3884篇 |
2015年 | 4509篇 |
2014年 | 6266篇 |
2013年 | 8989篇 |
2012年 | 12976篇 |
2011年 | 13766篇 |
2010年 | 8067篇 |
2009年 | 7320篇 |
2008年 | 12184篇 |
2007年 | 12885篇 |
2006年 | 12212篇 |
2005年 | 12087篇 |
2004年 | 11976篇 |
2003年 | 11260篇 |
2002年 | 11073篇 |
2001年 | 4865篇 |
2000年 | 4519篇 |
1999年 | 4154篇 |
1998年 | 2548篇 |
1997年 | 2076篇 |
1996年 | 1738篇 |
1995年 | 1699篇 |
1994年 | 1468篇 |
1993年 | 1439篇 |
1992年 | 2426篇 |
1991年 | 2343篇 |
1990年 | 2017篇 |
1989年 | 1933篇 |
1988年 | 1814篇 |
1987年 | 1653篇 |
1986年 | 1577篇 |
1985年 | 1524篇 |
1984年 | 1316篇 |
1983年 | 1211篇 |
1982年 | 1135篇 |
1981年 | 988篇 |
1980年 | 880篇 |
1979年 | 931篇 |
1978年 | 760篇 |
1977年 | 713篇 |
1975年 | 697篇 |
1974年 | 758篇 |
1973年 | 720篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Bone marrow fat content in relation to bone remodeling and serum chemistry in intact and ovariectomized dogs 总被引:6,自引:0,他引:6
R. Bruce Martin Ph.D. Betty D. Chow Paul A. Lucas 《Calcified tissue international》1990,46(3):189-194
Summary It was previously shown that 11 months after ovariectomy the volume fraction of trabecular bone in the spine and 11th rib
medullary canal of Beagle dogs (6 control, 9 ovariectomized) was significantly reduced. In this paper it is shown that these
changes are accompanied by increased marrow fat volume in the 11th rib (59.0±9.5% vs. 44.3 ±10.0%). Conversely, the volume
fraction of functional (hematopoietic) cells in the marrow was reduced by ovariectomy. Additionally, variations in marrow
fat volume were tested for correlation with 22 other variables pertinent to bone physiology. Marrow fat volume was significantly
positively correlated with serum osteocalcin, rib trabecular bone porosity, rib cross-sectional area, and gains in body weight.
It was negatively correlated with serum estrogen concentrations and the extent of rib trabecular surfaces labeled with tetracycline. 相似文献
992.
Summary This paper describes a new technique for the division of syndactyly. The commissure is reconstructed by a dorsal trilobed flap and a zig zag incision which produces triangular flaps for the side of the digits. This technique does not require use of a skin graft. Seventeen syndactylies in fourteen children, nine incomplete (six congenital and three secondary to burn) and eight complete syndactylies were treated by this technique. The results after a maximum of twelve months follow-up and the advantages of the technique are discussed.[/ab] 相似文献
993.
Arne T. Hstmark Einar Lystad Einar Jebens Jan Skramstad Paul Fryen 《Basic & clinical pharmacology & toxicology》1998,83(1):29-35
Abstract: Chlorinated fatty acids represent a major fraction of extractable, organically bound chlorine in fish. After dietary intake such fatty acids may be transferred from the mother to the foetus through the placenta, and via breast milk to the child. In the present work we have studied the effect of chlorinated oleic acid on the growth of three widely differing types of cells in culture. Chlorinated oleic acid inhibited growth of Human Microvascular Endothelial Cells (HMVEC), Immortilized Human Kidney Epithelial (IHKE) cells, and human Hepatoma cells (HepG2). The order of potency was: HMVEC > IHKE > HepG2. Vitamin E counteracted the inhibitory effect of chlorinated oleic acid on HepG2 cells, but did not significantly affect the fatty acid effect on HMVEC or IHKE. Defatted serum albumin stimulated the growth of HMVEC and IHKE. With HMVEC there was no major interaction between the effect of albumin and chlorinated oleic acid on cell growth. In contrast, with IHKE albumin at low concentration abolished the growth inhibiting effect of chlorinated oleic acid and appreciably counteracted growth inhibition by the fatty acid of HepG2 . We conclude that the growth modulation by chlorinated oleic acid and its interaction with vitamin E and albumin are cell specific. 相似文献
994.
Patrice Laloux Fabienne Richelle Patrick De Coster Jacques Jamart 《Journal of neuroimaging》1995,5(3):145-151
The sensitivity of single-photon emission computed tomography (SPECT) in evaluating posterior mculation infarcts compared with that of computed tomography (CT) or magnetic resonance imaging (MRI) remains unknown. In a hospital-based population, the authors studied SPECT, CT, and MRI in 35 consecutive patients presentmg with acute infarction clinically localized in the thalamus (7), posterior cerebral artery (PCA) territory (15), bramtem (19), and cerebellum (3) Multiple infarcts were noted m 8 patients. Overall, the SPECT sensitivity was lower than that of MRI (21% vs 93%, p ~ 0 004) and CT (42% vs 65%, p = 0 046) The SPECT and CT sensitivities were not Significantly different (67% vs 73%) for PCA Infarcts. Performed within 24 hours, SPECT showed a relevant hypoperfusion in all PCA mfarcts. For brainstem infarcts, CT (33%, p = 0 074) and MRI (91 %, p = 0.004) were more sensitive than SPECT, which showed no hemispheric hypoperfusion. The sensitivity of the three imaging techniques was 100% for large cerebellar infarcts. For the small group of thalamic infarcts, the SPECT, CT, and MRI sensitivities were 14, 71, and 100%, respectively. Thus, SPECT compared to CT and MRI is not helpful in the subacute phase to localize PCA and cerebellar infarcts and is of limited value for thalamic infarcts. In the first hours, the absence of cerebral hypoperfusion in brainstem mfarcts may help to differentiate them from hemispheric infarcts usually associated with profound hypoperfusion. 相似文献
995.
996.
Joseph C. Gretzula D.O. Osmar Hevia B.S. Lawrence S. Shachner M.D. John H. DiLiberti M.D. † R. H. A. Ruvalcaba M.D. ‡ James R. Schimshock M.D. § Richard G. Weleber M.D. Fahed Halal M.D. # Mark H. Lipson M.D. Bruce Blumberg M.D. †† Paul J. Weber M.D. 《Pediatric dermatology》1988,5(1):28-32
In 1980 a syndrome was first described in two adult males, consisting of macrocephaly, pigmented macules on the glans and shaft of the penis, and hamartomatous intestinal polyps. Since then, 10 additional cases have been identified. Herein, we present two new cases and review the cutaneous manifestations as well as additional features in patients with the Ruvalcaba-Myhre-Smith syndrome. 相似文献
997.
998.
999.
1000.
Rapid determination of trisomy 18 parental origin using fluorescent PCR and small tandem repeat markers: case reports 总被引:3,自引:0,他引:3
Ian Findlay Tamás Tóth Paul Matthews Tamás Marton Philip Quirke Zoltán Papp 《Clinical genetics》1998,53(2):92-95
Trisomy 18 is the second most common genetic defect after trisomy 21, almost 90% of which are due to additional chromosome from the mother. The parental origin of the additional chromosome can, if required, be determined by two methods: karyotyping, which takes several weeks; or, more recently, by polymerase chain reaction (PCR) which is often problematic. Fluorescent PCR of small tandem repeats (STRs) can determine the parental origin in the majority of cases within 5 h. Although the incidence of paternal origin is known for both trisomy 21 and trisomy 18, this technique can rapidly determine the parental origin in cases where there is insufficient samples to perform conventional tests. Determining parental origin by these methods may also have clinical significance in the diagnosis of chromosomal translocations or in the diagnosis of genetic disease using linkage analysis. 相似文献