全文获取类型
收费全文 | 47800篇 |
免费 | 3446篇 |
国内免费 | 1535篇 |
专业分类
耳鼻咽喉 | 373篇 |
儿科学 | 964篇 |
妇产科学 | 345篇 |
基础医学 | 5792篇 |
口腔科学 | 2324篇 |
临床医学 | 3171篇 |
内科学 | 4451篇 |
皮肤病学 | 239篇 |
神经病学 | 1379篇 |
特种医学 | 2588篇 |
外国民族医学 | 1篇 |
外科学 | 12855篇 |
综合类 | 4979篇 |
现状与发展 | 1篇 |
预防医学 | 2253篇 |
眼科学 | 118篇 |
药学 | 6440篇 |
12篇 | |
中国医学 | 2522篇 |
肿瘤学 | 1974篇 |
出版年
2023年 | 436篇 |
2022年 | 1009篇 |
2021年 | 1226篇 |
2020年 | 1057篇 |
2019年 | 1038篇 |
2018年 | 1162篇 |
2017年 | 1057篇 |
2016年 | 1313篇 |
2015年 | 1471篇 |
2014年 | 2552篇 |
2013年 | 2752篇 |
2012年 | 2279篇 |
2011年 | 2620篇 |
2010年 | 2177篇 |
2009年 | 2244篇 |
2008年 | 2224篇 |
2007年 | 2265篇 |
2006年 | 2178篇 |
2005年 | 2647篇 |
2004年 | 2393篇 |
2003年 | 1863篇 |
2002年 | 1201篇 |
2001年 | 1114篇 |
2000年 | 1075篇 |
1999年 | 936篇 |
1998年 | 772篇 |
1997年 | 764篇 |
1996年 | 706篇 |
1995年 | 781篇 |
1994年 | 729篇 |
1993年 | 678篇 |
1992年 | 583篇 |
1991年 | 527篇 |
1990年 | 428篇 |
1989年 | 422篇 |
1988年 | 406篇 |
1987年 | 354篇 |
1986年 | 351篇 |
1985年 | 342篇 |
1984年 | 294篇 |
1983年 | 114篇 |
1982年 | 278篇 |
1981年 | 245篇 |
1980年 | 222篇 |
1979年 | 229篇 |
1978年 | 196篇 |
1977年 | 175篇 |
1976年 | 172篇 |
1973年 | 128篇 |
1972年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
应用双光子及单光子吸收测定技术,检测了92名出生3d内的新生儿骨矿质含量,其中巨大儿30名,正常体重儿32名,低出生体重儿30名,其孕龄分别是40.1±0.7、39.1±1.5和37.4±1.2孕周。结果表明,巨大儿、正常体重儿、低出生体重儿的全身骨矿质含量分别是101.6±28.8、85.2±19.8、59.9±27.2g/cm2,巨大儿骨矿质含量最高,正常体重儿次之,低出生体重儿最低,差异有显著性(P<0.01)。颅骨、肱骨、股骨的骨矿质含量与全身的骨矿质含量有高度的相关性,相关系数分别是0.943、0.879和0.745(P<0.01)。全身的骨矿质含量与出生体重、孕龄及头围有高度相关性,相关系数分别是0.755、0.596和0.556(P<0.01)。提示颅骨、肱骨及股骨的任一部位均可代表全身的骨矿质含量,肱骨是确定全身骨矿质含量较好的部位,新生儿骨矿质含量受出生体重、孕龄及头围的影响较大。 相似文献
92.
An advanced analysis of the mechanical properties of bone should include information about the microarchitecture of cancellous bone in addition to its density. It has recently been shown that high-resolution quantitative computed tomography and magnetic resonance imaging have the potential to assess such information in a noninvasive way in patients. Both techniques, however, lack sufficient spatial resolution to image the individual trabeculae with true precision. In this work, a new parameter, Ridge number density (RND), is introduced. RND is a measure for the trabecular number, which can be extracted directly from high-resolution three-dimensional (3D) images of patients. We applied the RND technique to a test group of nine healthy, postmenopausal women measured repetitively with a high-resolution 3D peripheral quantitative computed tomography (3D-pQCT) system with 165 × 165 × 165 μm3 voxel size. Simultaneously with the RND determination, the trabecular bone density (TBD) was also assessed in the same volume of interest. The examination site was the distal radius. The intersubject variability of the measured test group was 10.5% for RND and 26.3% for TBD. The root mean square error between first and second examinations (midterm reproducibility) was 1.6% and 1.1%, respectively. RND is determined independently from TBD and pertains to the structure of the cancellous bone. As such, it might add crucial information in cases where bone mass or bone density measurements alone give ambigous results. 相似文献
93.
94.
近3年来,用制备的胎骨充填良性骨肿瘤及病样病变术后骨缺损,经观察10例效果良好。胎骨因其自身组织学和生理学特点,具有抗原性小、诱导成骨活性高,利于“爬行各代”等优点。而且来源丰富、采制简单、储存容易、费用低度,是一种良好的植骨材料,特别适于儿童及年老体弱患者自身取骨困难的骨缺损植骨需要。但其为异体骨,有一定免疫原性,抗支撑强度略差,应注意严格无菌操作、消除免疫原性、配合使用内、外固定等措施。 相似文献
95.
18例慢性肾衰继发性甲旁亢病人发现有锁骨骨吸收。发病部位包括锁骨内端、外端、外1/3下缘及内段下缘4个部位。其中锁骨内、外端骨吸收属软骨下骨吸收,内、外段下缘骨吸收属韧带下骨吸收。作者对锁骨骨吸收的X线表现及发病机制作了讨论。认为锁骨骨吸收是继发性甲旁亢的重要X线征象,对诊断肾性骨病具有重要的意义。 相似文献
96.
Alpha2-HS glycoprotein phenotypes and quantitative hormone and bone measures in postmenopausal women
June E. Eichner Christopher A. Friedrich Jane A. Cauley Mohammad I. Kamboh James P. Gutai Lewis H. Kuller Robert E. Ferrell 《Calcified tissue international》1990,47(6):345-349
Summary It has been suggested that inherited traits play a role in the development of osteoporosis by providing a background for the
modulation of gene expression. In this study, we examine the influence of the different alleles of alpha2-HS glycoprotein (AHSG), a protein of the bone matrix, on quantitative estrogens, estrone and estradiol, and bone measures,
bone area and density. Estrogens provide a protective effect against fractures in older women and were thus included in the
analyses. Isoelectric focusing of AHSG from sera followed by immunoblotting was used to type 163 white post-menopausal women
participating in a clinical trial of the effects of walking on bone loss. Plasma hormones were measured by a combination of
extraction, column chromatography, and radioimmunoassay; bone measures on the dominant radius were determined with computerized
tomography. Analysis of variance was done on estrogen and bone measures after controlling for the effects of age and body
mass index. The two major alleles of AHSG result in three phenotypes, designated AHSG 1-1, AHSG 2-1, and AHSG 2-2. The AHSG
1-1 homozygote showed a decreased concentration of estradiol, the AHSG 2-2 homozygote showed an increased concentration, and
the AHSG 2-1 heterozygote was intermediate (P=0.001). Estrone demonstrated a similar pattern in residual analysis although it did not reach statistical significance. 相似文献
97.
98.
99.
为探讨无名异接骨冲剂加速骨折愈合的作用机理,选用55只新西兰大白兔,随机选择5只作为正常组;另50只在无菌条件下造成双桡骨标准骨折模型。将50只骨折兔随机平均分为实验组和对照组,实验组用无名异接骨冲剂每天4g/kg溶于20ml蒸馏水中分早晚两次灌胃;对照组用20ml蒸馏水灌胃。于骨折后第1,2,3,4及5周用断颈法每次每组处死5只兔,取骨痂进行抗骨形态发生蛋白(BMP)单克隆抗体免疫组化染色,并用CMIAS型图像分析仪对BMP含量进行定量分析。结果发现:实验组骨折局部BMP含量明显高于正常组(P<0.01);第1,2周实验组明显高于对照组(P<0.01);实验组BMP高峰出现在第2周,而对照组出现在第3周。认为,无名异接骨冲剂能促进成骨细胞合成BMP,使BMP峰值提前,从而加速骨折愈合。 相似文献
100.
Masatoshi Chiba Takashi Shigihara Seishi Echigo Teiichi Teshima 《Journal of bone and mineral metabolism》1990,8(3):24-29
Summary In this study, we examined histologically the effect of a bone morphogenetic protein (BMP) derived from bovine tooth on the
periosteum. Supraperiosteal injection of crude BMP into femurs of Wistar rats (28 day old) resulted in periosteal cell proliferation
with subsequent bone and cartilage formation. Moreover, proliferating periosteal cells migrated into injected BMP, and formed
both cartilage and bone. These observations show that exogenous BMP stimulates mesenchymal cells of the periosteum to proliferate
and differentiate into osteoblasts, and therefore BMP may be one of factors which are involved in differentiation of osteoblasts
in the periosteum. 相似文献