全文获取类型
收费全文 | 38601篇 |
免费 | 5823篇 |
国内免费 | 2145篇 |
专业分类
耳鼻咽喉 | 968篇 |
儿科学 | 787篇 |
妇产科学 | 780篇 |
基础医学 | 2839篇 |
口腔科学 | 747篇 |
临床医学 | 4954篇 |
内科学 | 6197篇 |
皮肤病学 | 843篇 |
神经病学 | 2521篇 |
特种医学 | 1511篇 |
外国民族医学 | 11篇 |
外科学 | 6460篇 |
综合类 | 5425篇 |
现状与发展 | 8篇 |
一般理论 | 2篇 |
预防医学 | 3202篇 |
眼科学 | 834篇 |
药学 | 3099篇 |
33篇 | |
中国医学 | 1990篇 |
肿瘤学 | 3358篇 |
出版年
2024年 | 237篇 |
2023年 | 1058篇 |
2022年 | 1456篇 |
2021年 | 2008篇 |
2020年 | 2039篇 |
2019年 | 1259篇 |
2018年 | 1718篇 |
2017年 | 1711篇 |
2016年 | 1738篇 |
2015年 | 2190篇 |
2014年 | 2701篇 |
2013年 | 2961篇 |
2012年 | 2845篇 |
2011年 | 2801篇 |
2010年 | 2440篇 |
2009年 | 2263篇 |
2008年 | 1906篇 |
2007年 | 1637篇 |
2006年 | 1585篇 |
2005年 | 1306篇 |
2004年 | 901篇 |
2003年 | 866篇 |
2002年 | 761篇 |
2001年 | 695篇 |
2000年 | 523篇 |
1999年 | 496篇 |
1998年 | 391篇 |
1997年 | 440篇 |
1996年 | 435篇 |
1995年 | 393篇 |
1994年 | 284篇 |
1993年 | 183篇 |
1992年 | 237篇 |
1991年 | 235篇 |
1990年 | 159篇 |
1989年 | 200篇 |
1988年 | 178篇 |
1987年 | 142篇 |
1986年 | 140篇 |
1985年 | 123篇 |
1984年 | 111篇 |
1983年 | 89篇 |
1982年 | 85篇 |
1981年 | 59篇 |
1980年 | 71篇 |
1979年 | 45篇 |
1978年 | 58篇 |
1977年 | 55篇 |
1976年 | 39篇 |
1975年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: Autoantibody production by the fetus is thought to be extremely unlikely. Only one possible case of in utero autoantibody production against red cells by the fetus has previously been described. STUDY DESIGN AND METHODS: A case of apparent red cell IgG autoantibody production in utero is reported. RESULTS: This was established by a positive direct antiglobulin test in a newborn infant without evidence of maternal alloantibodies or autoantibodies. There was no evidence of clinically significant hemolysis at the infant's birth. After 6 weeks, his direct antiglobulin test remained strongly positive. The infant thrived without evidence of hemolysis, and after 6 months the direct antiglobulin test was negative. CONCLUSION: The production of autoantibodies to red cells in utero is possible, though rare. This did not result in apparent hemolysis in this patient. 相似文献
62.
63.
64.
BACKGROUND AND PURPOSE: Hysterectomy is among the most frequently performed surgical procedures in developed countries, but few studies from the Asia-Pacific region have assessed the appropriateness of hysterectomy. The purpose of this study was to examine the rate of inappropriate hysterectomy in Taiwan and its association with patient characteristics and indications for the procedure. METHODS: A random sample of hysterectomies for which claims were submitted to the Taiwan Bureau of National Health Insurance from July 1, 1997 to June 30, 1998 was selected. A total of 658 charts were reviewed by an expert panel composed of 5 senior gynecologists. RESULTS: Overall, 74.2% of patients underwent hysterectomy for appropriate reasons, 5.6% for uncertain reasons, and 20.2% for inappropriate reasons. Inappropriate procedures were positively associated with younger age and premenopausal status. Primary indications that accounted for over 25% of inappropriate procedures were chronic pelvic pain (42.9%), abnormal uterine bleeding (37.5%), and endometriosis (27.7%). CONCLUSIONS: This study found a high rate of inappropriate hysterectomy in Taiwan. Gynecologists and physician organizations should take action to improve physician agreement on the use of hysterectomy, especially for indications associated with high rates of inappropriate procedures. 相似文献
65.
66.
Is neurogenesis reparative after status epilepticus? 总被引:1,自引:0,他引:1
67.
R C Chao 《Journal of ultrasound in medicine》1993,12(11):645-646
68.
宫颈粘液过氧化物酶在月经周期中的变化规律 总被引:3,自引:1,他引:2
本文对29例月经周期正常妇女的宫颈粘液过氧化物酶进行了30个周期的研究。在月经周期不同时间测定宫颈粘液过氧化物酶(CMPx)活性及血清促黄体生成素(LH)、雌二醇(E_2)和孕酮(P)。结果表明:在排卵前三天酶活性明显下降,至排卵后一天开始上升。卵泡期,酶活性与E_2呈负相关(r=-0.67);黄体期,酶活性与P呈正相关(r=0.79)。本研究提示:1.CMPx在排卵周期具有特定的变化规律,其变化受体内激素水平影响,可作为预告排卵的指标。2.如简化测定方法,可为自然避孕提供新途径。 相似文献
69.
Preparation and characterization of porous beta-tricalcium phosphate/collagen composites with an integrated structure 总被引:11,自引:0,他引:11
Porous beta-tricalcium phosphate (TCP)/collagen composites with different beta-TCP/collagen weight ratio were prepared. The influences of the preparation conditions on the microstructure of porous composite and the joint status of beta-TCP particles with collagen fibrils were characterized by X-ray diffractometer, scanning electron microscopy and transmission electron microscopy. The results showed: (1) an acid treatment could effectively disassemble collagen fibrils; (2) in the resulting porous composites, beta-TCP particles homogenously existed on the skeleton of the collagen fibril network and bonded tightly to both the fibrils and themselves. The tight bonding formation could be due to the reaction between Ca ions in the particles and carboxyl groups in collagen polypeptide chains and due to the reprecipitation of partially dissolved beta-TCP during synthesis. The tight bonding between beta-TCP particles and collagen fibrils in the composites demonstrated an integrated structure, which was reproducible when beta-TCP/collagen ratio ranged from 2 to 4. Such integrated structure would make significant contributions in reliably tailoring properties of the porous composites by varying beta-TCP content. In addition, the porous composites had large porosity (approximately 95%) and appropriate pore size (approximately 100 microm), showed no negative impact in cytotoxicity assay and complete bone tissue regeneration after 12 weeks in animal test. 相似文献
70.
Yin C Ying L Zhang PC Zhuo RX Kang ET Leong KW Mao HQ 《Journal of biomedical materials research. Part A》2003,67(4):1093-1104
Galactosylated surface is an attractive substrate for hepatocyte culture because of the specific interaction between the galactose ligand and the asialoglycoprotein receptor on hepatocytes. In this study, we described a scheme to achieve high density of immobilized galactose ligands on polyethylene terephthalate (PET) surface by first surface-grafting polyacrylic acid on plasma-pretreated PET film under UV irradiation, followed by conjugation of a galactose derivative (1-O-(6'-aminohexyl)-D-galactopyranoside) to the grafted polyacrylic acid chains. A high galactose density of 513 nmol/cm(2) on the PET surface was used in this study to investigate the behavior of cultured hepatocyte. This engineered substrate showed high affinity to fluorescein isothiocyanate-lectin binding. Primary rat hepatocytes, when seeded at a density of 2 x 10(5) cells/cm(2), attached to the galactosylated PET substrate at a similar efficiency compared with collagen-coated substrate. The hepatocytes spontaneously formed aggregates 1 day after cell seeding and showed better maintenance of albumin secretion and urea synthesis functions than those cultured on collagen-coated surface. 相似文献