全文获取类型
收费全文 | 23815篇 |
免费 | 1966篇 |
国内免费 | 469篇 |
专业分类
耳鼻咽喉 | 450篇 |
儿科学 | 739篇 |
妇产科学 | 427篇 |
基础医学 | 2406篇 |
口腔科学 | 313篇 |
临床医学 | 2451篇 |
内科学 | 3785篇 |
皮肤病学 | 355篇 |
神经病学 | 2037篇 |
特种医学 | 1138篇 |
外国民族医学 | 1篇 |
外科学 | 2248篇 |
综合类 | 2422篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 3156篇 |
眼科学 | 956篇 |
药学 | 1079篇 |
12篇 | |
中国医学 | 741篇 |
肿瘤学 | 1529篇 |
出版年
2024年 | 61篇 |
2023年 | 479篇 |
2022年 | 937篇 |
2021年 | 1284篇 |
2020年 | 1075篇 |
2019年 | 1119篇 |
2018年 | 1014篇 |
2017年 | 908篇 |
2016年 | 866篇 |
2015年 | 746篇 |
2014年 | 1500篇 |
2013年 | 1756篇 |
2012年 | 1178篇 |
2011年 | 1333篇 |
2010年 | 1054篇 |
2009年 | 1027篇 |
2008年 | 1073篇 |
2007年 | 1092篇 |
2006年 | 891篇 |
2005年 | 807篇 |
2004年 | 682篇 |
2003年 | 659篇 |
2002年 | 526篇 |
2001年 | 443篇 |
2000年 | 346篇 |
1999年 | 334篇 |
1998年 | 317篇 |
1997年 | 276篇 |
1996年 | 213篇 |
1995年 | 211篇 |
1994年 | 189篇 |
1993年 | 186篇 |
1992年 | 157篇 |
1991年 | 125篇 |
1990年 | 122篇 |
1989年 | 128篇 |
1988年 | 95篇 |
1987年 | 116篇 |
1986年 | 106篇 |
1985年 | 132篇 |
1984年 | 118篇 |
1983年 | 94篇 |
1982年 | 90篇 |
1981年 | 74篇 |
1980年 | 68篇 |
1979年 | 63篇 |
1978年 | 45篇 |
1977年 | 39篇 |
1976年 | 17篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
121.
目的:探讨非小细胞肺癌患者治疗前血清肿瘤标志物水平与肿瘤骨转移之间的相关性。材料和方法:受检患者58名治疗前均行血清Cy21-1、SCC、NSE、CEA和CA15-3测定和SPECT全身骨显像。结果:血清Cy21-1和CA15-3水平与全身骨显像结果相关。(P<0.05),血清SCC,NSE及CEA水平则无相关(P>0.05)。结论:血清中Cy21-1和CA15-3升高水平与肿瘤骨转移之间存在正相关关系,尤以Cy21-1为著。 相似文献
122.
应用拉丁方设计,在不同体重组的大鼠,于不同时辰,对交叉上核采取不同强度的刺激,用放射免疫法测定外周血中皮质酮的含量。其结果显示:各体重组间无显著性差异,不同时辰血浆皮质酮的平均含量各组呈现基本相同的节律性变化,无论何时辰刺激交叉上核使之兴奋,均可显著提高血浆皮质酮的含量。完全损毁交叉上核后72小时血浆皮质酮含量和正常对照组无显著性差异,且其节律性也没有出现明显变化。 相似文献
123.
Histological, immunohistochemical, and electron microscopic evidence of an extracellular, or ghost Pick body has been found in the granular cell layer and, rarely, in the pyramidal cell layer of the hippocampus of an autopsy case of Pick's disease. The ghost Pick body appeared as a blurred, weak argyrophilic mass in the neuropil, and it was composed of accumulated fibrillary structures, 13 nm in diameter, intermingled with glial filament bundles. These ghost Pick bodies did not react with anti-tau and antiubiquitin antibodies, but did react weakly with antiglial fibrillary acidic protein antibody, whereas intracytoplasmic Pick bodies were strongly immunolabeled with anti-tau but only weakly with anti-ubiquitin anti-bodies. These results suggest that the Pick body is discharged into the neuropil after destruction of the mother neuron, loses its immunoreactivity to certain tau and ubiquitin antibodies during this process (thereby inducing a glial reaction) and remains in the neuropil as a ghost Pick body. 相似文献
124.
T. W. Boesgaard S. I. Castella G. Andersen A. Albrechtsen T. Spars K. Borch‐Johnsen T. Jrgensen T. Hansen O. Pedersen 《Diabetic medicine》2007,24(7):702-706
AIMS: The glutamate decarboxylase gene (GAD2) encodes GAD65, an enzyme catalysing the production of the gamma-aminobutyric acid (GABA) which interacts with neuropeptide Y to stimulate food intake. It has been suggested that in pancreatic islets, GABA serves as a functional regulator of pancreatic hormone release. Conflicting results have been reported concerning the potential impact of GAD2 variation on estimates of energy metabolism. The aim of this study was to elucidate potential associations between the GAD2-243A-->G polymorphism and levels of body mass index (BMI) and estimates of glycaemia. METHODS: Using high-throughput chip-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, the GAD2-243A-->G (rs2236418) polymorphism was genotyped in a population-based sample (Inter99) of 5857 middle-aged, unrelated Danish White subjects. RESULTS: The G-allele was associated with modestly lower BMI (P = 0.01). In a case-control study of obesity, the G-allele frequency in 2582 participants with BMI < 25 kg/m2 was 19.5% (18.4-20.6) compared with 17.1% (15.5-18.8) in 968 participants having BMI > or = 30 kg/m2 (P = 0.03), odds ratio 0.9 (0.7-1.0). Of the 5857 subjects, GG carriers had lower fasting plasma glucose levels (mmol/l) [AA (n = 3859) 5.6 +/- 0.8; AG (n = 1792) 5.5 +/- 0.8; GG (n = 206) 5.5 +/- 0.8, P = 0.008] and lower 30-min oral glucose tolerance test (OGTT)-related plasma glucose levels (AA 8.7 +/- 1.9; AG 8.6 +/- 1.9; GG 8.6 +/- 2.0, P = 0.04), adjusted for sex, age and BMI. Analysing subjects who were both normoglycaemic and glucose tolerant (n = 4431) GG carriers still had lower fasting plasma glucose concentrations: AA (n = 2895) 5.3 +/- 0.4; AG (n = 1383) 5.3 +/- 0.4; GG (n = 153) 5.2 +/- 0.4 (P = 9.10(-5)). CONCLUSION: The present study suggests that the GAD2-243A-->G polymorphism in a population of middle-aged White people associates with a modest reduction in BMI and fasting and OGTT-related plasma glucose levels. 相似文献
125.
目的 观察玻璃体视网膜手术后早期睫状体脱离的发生率及其自然病程,并分析其与手术后早期低眼压的关系。方法 利用超声生物显微镜检查(UBM)连续观察行玻璃体视网膜手术治疗的患者46例46只眼。按玻璃体视网膜手术后不同填充内容分组:气体填充组11例11只眼,硅油填充组8例8只眼,平衡盐溶液(BSS)填充组27例27只眼。按手术后眼压分组:眼压<10 mm Hg(1 mm Hg=0.133 kPa)组25例25只眼,≥10 mm Hg组21例21只眼。玻璃体视网膜手术后第3天行UBM确定有无睫状体脱离,手术后每天用非接触眼压计监测眼压,有睫状体脱离者每隔7 d复查1次,直至睫状体脱离复位,所有患者均随访观察14~35 d。结果 手术后睫状体脱离20例,占本组患者的43.5%。无睫状体脱离者26例,占本组患者的56.5%。玻璃体视网膜手术后气体填充组睫状体脱离发生率 27.3%,硅油填充组25.0%,而BSS填充组为55.6%。睫状体脱离者手术后平均眼压(6.47±4.49) mm Hg (1 mm Hg=0.133 kPa),无睫状体脱离者平均眼压(15.61±7.72) mm Hg,两者差异有统计学意义(t=8.031,P<0.001)。手术后眼压<10 mm Hg组患者睫状体脱离发生率为68.0%,眼压≥10 mm Hg组患者睫状体脱离发生率为14.3%,两组差异有统计学意义(χ2=15.60, P<0.001)。玻璃体视网膜手术后早期睫状体脱离患者除1例因低眼压引起视盘水肿而需行气体填充外,其余患者均在手术后30 d内自行复位。结论 手术后早期睫状体脱离是玻璃体视网膜手术的常见并发症。玻璃体视网膜手术后行BSS填充患者手术后睫状体脱离的发生率高。绝大多数患者睫状体脱离能够在玻璃体视网膜手术后30 d内自行复位。 相似文献
126.
Eight-channel transmit/receive body MRI coil at 3T. 总被引:1,自引:0,他引:1
P. Vernickel P. Röschmann C. Findeklee K.‐M. Lüdeke Ch. Leussler J. Overweg U. Katscher I. Grässlin K. Schünemann 《Magnetic resonance in medicine》2007,58(2):381-389
Multichannel transmit magnetic resonance imaging (MR) systems have the potential to compensate for signal-intensity variations occurring at higher field strengths due to wave propagation effects in tissue. Methods such as RF shimming and local excitation in combination with parallel transmission can be applied to compensate for these effects. Moreover, parallel transmission can be applied to ease the excitation of arbitrarily shaped magnetization patterns. The implementation of these methods adds new requirements in terms of MRI hardware. This article describes the design of a decoupled eight-element transmit/receive body coil for 3T. The setup of the coil is explained, starting with standard single-channel resonators. Special focus is placed on the decoupling of the elements to obtain independent RF resonators. After a brief discussion of the underlying theory, the properties and limitations of the coil are outlined. Finally, the functionality and capabilities of the coil are demonstrated using RF measurements as well as MRI sequences. 相似文献
127.
AIMS: Overweight is common during late puberty in female patients with Type 1 diabetes. The aim of this study was to examine the change in body composition from late puberty to early adulthood in such female patients in comparison with age-matched control subjects. METHODS: Eighteen females with Type 1 diabetes and 19 healthy female control subjects were recruited for a case-control study at the age of 16-19 years (baseline). Six years later, 16 of the diabetic females and 17 of the control subjects were re-examined (follow-up). Body composition was assessed by dual energy X-ray absorptiometry. RESULTS: Body mass index (BMI) and fat mass index (total fat mass/height2) were significantly higher at baseline in the diabetic patients than in the control subjects (26.4 +/- 2.6 vs. 23.9 +/- 3.7 kg/m2, P < 0.05, and 10.0 +/- 2.4 vs. 8.0 +/- 2.8 kg/m2, P = 0.04, respectively). At follow-up, these parameters still tended to be higher in the diabetic group (27.8 +/- 4.9 vs. 24.6 +/- 5.7 kg/m2, P = 0.09, and 11.8 +/- 5.6 vs. 8.7 +/- 4.9 kg/m2, P = 0.05, respectively). BMI at baseline was strongly correlated to BMI at follow-up in both diabetic patients (r = 0.60; P < 0.05) and control subjects (r = 0.83; P < 0.01). CONCLUSIONS: Increased fat mass in pubertal girls with Type 1 diabetes seems to persist in young adulthood. This study emphasizes the need for new strategies to prevent the development of overweight during puberty in diabetic girls. 相似文献
128.
目的评价两步活检一、二极体对小鼠卵母细胞体外受精(IVF)和相应胚胎发育的影响。方法8~12周龄雌、雄昆明小鼠。雌鼠促排卵,取成熟卵母细胞行卵胞浆内单精子注射(ICSI),序贯培养胚胎至囊胚孵出。分别于ICSI后激光透明带打孔活检第一极体,两步活检一、二极体,在受精后打孔同时活检一、二极体。比较各处理组与对照组受精、卵裂、优质胚胎、囊胚形成、扩张和孵出情况。结果两步活检一、二极体和同时活检一、二极体受精率、卵裂率、优质胚胎率和囊胚形成率与对照组均无明显差异。启动孵出率明显高于对照组;完全孵出率虽高于对照组,但无统计学意义。结论一、二极体活检不影响小鼠卵母细胞IVF和相应胚胎发育,而且可能有助于胚胎孵出,是安全可行的植入前遗传学诊断(PGD)活检取材方法,以两步活检法为最佳极体活检方案。 相似文献
129.
Although only recently introduced, chemically-modified hyaluronic acid dermal fillers have gained widespread acceptance as “redefining” dermal fillers in the fields of dermatology and cosmetic facial surgery. Although hyaluronic acid-based dermal fillers have a low overall incidence of long term side effects, occasional adverse outcomes, ranging from chronic lymphoplasmacytic inflammatory reactions to classic foreign body-type granulomatous reactions have been documented. These long-term adverse events are reviewed. 相似文献
130.
头低位模拟失重状态对前庭功能的影响 总被引:4,自引:1,他引:3
为研究头低位模拟失重对运动病症状、垂直视动眼震(VOKN)及体液重新分配的影响,在头低位-10°的模拟失重状态下,采用大视野的垂直视动刺激,观察18名正常人的运动病症状、VOKN、激素(AVP、VIP、CORT、ALDO)的反应特点。结果表明,头低位-10°状态下的大视野垂直视动刺激可以诱发出明显的运动病症状,头低位-10°的垂直视动刺激比坐位更容易诱发运动病。坐位状态VOKN慢相速度有明显的方向性不对称,敏感组VOKN方向性不对称有显著差异(P<0.05)。头低位-10°时VOKN的不对称现象不明显,向下方向运动的VOKN慢相速度显著增加。分析指出,头低位-10°状态下垂直视动刺激比坐位和秋千刺激的贡献率大。尿中CORT(皮质醇)在秋千和头低位的垂直视动刺激前后有显著性增加。提示:大视野的垂直视动刺激与头低位-10°两种刺激的结合可能成为预测空间运动病的方法之一. 相似文献