全文获取类型
收费全文 | 30449篇 |
免费 | 2068篇 |
国内免费 | 816篇 |
专业分类
耳鼻咽喉 | 85篇 |
儿科学 | 1439篇 |
妇产科学 | 1333篇 |
基础医学 | 2906篇 |
口腔科学 | 175篇 |
临床医学 | 2844篇 |
内科学 | 5688篇 |
皮肤病学 | 233篇 |
神经病学 | 2736篇 |
特种医学 | 581篇 |
外国民族医学 | 9篇 |
外科学 | 3197篇 |
综合类 | 4117篇 |
现状与发展 | 5篇 |
预防医学 | 1708篇 |
眼科学 | 71篇 |
药学 | 3260篇 |
36篇 | |
中国医学 | 1235篇 |
肿瘤学 | 1675篇 |
出版年
2024年 | 51篇 |
2023年 | 384篇 |
2022年 | 657篇 |
2021年 | 1184篇 |
2020年 | 960篇 |
2019年 | 879篇 |
2018年 | 880篇 |
2017年 | 978篇 |
2016年 | 960篇 |
2015年 | 941篇 |
2014年 | 1661篇 |
2013年 | 2086篇 |
2012年 | 1457篇 |
2011年 | 1707篇 |
2010年 | 1450篇 |
2009年 | 1278篇 |
2008年 | 1335篇 |
2007年 | 1319篇 |
2006年 | 1348篇 |
2005年 | 1152篇 |
2004年 | 964篇 |
2003年 | 910篇 |
2002年 | 790篇 |
2001年 | 712篇 |
2000年 | 650篇 |
1999年 | 504篇 |
1998年 | 441篇 |
1997年 | 454篇 |
1996年 | 465篇 |
1995年 | 409篇 |
1994年 | 392篇 |
1993年 | 332篇 |
1992年 | 364篇 |
1991年 | 331篇 |
1990年 | 357篇 |
1989年 | 284篇 |
1988年 | 217篇 |
1987年 | 200篇 |
1986年 | 207篇 |
1985年 | 268篇 |
1984年 | 232篇 |
1983年 | 151篇 |
1982年 | 193篇 |
1981年 | 160篇 |
1980年 | 133篇 |
1979年 | 120篇 |
1978年 | 107篇 |
1977年 | 84篇 |
1976年 | 64篇 |
1975年 | 50篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
31.
Akira Sawaki Nobumasa Mizuno Kuniyuki Takahashi Tsuneya Nakamura Masahiro Tajika Hiroki Kawai Toshifumi Isaka Hiroshi Imaoka Yasuyuki Okamoto Masatoshi Aoki Hiroyuki Inoue Ahmed AS Salem Yasushi Yatabe Kenji Yamao 《Digestive endoscopy》2006,18(1):40-44
Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed. 相似文献
32.
Prevalence of vitamin D depletion among morbidly obese patients seeking gastric bypass surgery 总被引:5,自引:0,他引:5
Arthur M. Carlin M.D. D. Sudhaker Rao MB B.S. F.A.C.P. F.A.C.E. Ali M. Meslemani M.D. Jeffrey A. Genaw M.D. Nayana J. Parikh Shiri Levy M.D. Arti Bhan M.D. Gary B. Talpos M.D. 《Surgery for obesity and related diseases》2006,2(2):696-103
BACKGROUND: Abnormalities in calcium and vitamin D metabolism have been reported after bariatric surgery. The purpose of this study was to evaluate vitamin D nutritional status among morbidly obese patients before gastric bypass surgery. METHODS: We prospectively studied 279 morbidly obese patients seeking gastric bypass surgery for vitamin D nutritional status as assessed by serum 25-hydroxyvitamin D level. In addition, serum samples were analyzed for calcium, alkaline phosphatase (AP), intact parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D. RESULTS: Mean patient age was 43 +/- 9 years; 87% of the study patients were women, and 72% were white. Serum calcium and AP levels were normal in 88% and 89% of the patients, respectively. Vitamin D depletion, defined as serum 25-hydroxyvitamin D level 相似文献
33.
L. L. Morselli L. Manetti C. Cosci C. Sardella F. Bogazzi C. Faldini E. Martino M. Gasperi 《Journal of orthopaedics and traumatology》2006,7(4):169-175
Growth hormone (GH) is fundamental for the maintenance of bone mass and metabolism both during childhood and in adulthood.
This effect is due to a complex interaction between circulating GH and IGF-I produced peripherally. In vitro data and experimental
animal models have clarified many of the regulatory mechanisms underlying the characteristic skeletal changes occurring in
acromegaly. This review focuses on the effects of GH excess on bone metabolism and mass in acromegalic patients and, in particular,
on the influence of factors such as hypogonadism, gender, age and therapy on bone metabolism and arthropathy. 相似文献
34.
目的探讨早期联用美罗培南(MEP)和大剂量重组人生长激素(rhGH)对严重烫伤免疫抑制大鼠肠源性感染的影响。方法Wistar大鼠54只随机分为对照组、烧伤组和治疗组(C1组、C2组、C3组),后两大组制成25%总体表面积(TBSA)Ⅲ°烫伤免疫抑制模型,伤后2h给予rhGH1.33IU/kg、MEP20mg/kg,伤后8、24h检测门静脉血清内毒素(LPS)、腔静脉血清肿瘤坏死因子-α(TNF-α)含量,肝功能变化和肠道细菌移位率。结果C3(MEP+rhGH治疗)组LPS和TNF-α含量均显著低于其他组(P<0.01),与对照组差异无统计学意义(P>0.05),C3组未发现肠道细菌移位且肝功能检测指标显著低于其他组(P<0.01),与对照组差异无统计学意义(P>0.05)。结论早期联用MEP和rhGH治疗严重烫伤免疫抑制大鼠能显著减轻或防止肠道细菌/内毒素移位,减少炎症介质释放,保护脏器功能。 相似文献
35.
目的 观察高转换型肾性骨病中骨保护素及其配体 (OPG,RANKL)的表达,并与骨形态计量学指标进行相关分析。 方法 选择10例慢性肾衰尿毒症患者和3例正常人进行髂骨活检术,获得骨组织标本。采用免疫组化方法检测OPG和RANKL蛋白质的表达。采用全自动图像分析系统进行骨组织形态计量学测定。结果 10例慢性肾衰尿毒症患者经骨病理学检查证实均为高转换型骨病,以破骨细胞活化形成骨吸收陷窝伴或不伴骨矿化不全为特点。免疫组化显示尿毒症患者骨组织中以RANKL阳性表达为主。与正常对照相比,RANKL阳性表达细胞数目显著增加,OPG阳性表达细胞数目显著减少。尿毒症患者RANKL的阳性表达细胞数目与骨吸收面积和破骨细胞数目呈显著正相关。结论 高转换型肾性骨病中,PTH的溶骨作用可能是通过OPG/RANKL/RANK系统介导的。 相似文献
36.
关于抑制素的回顾与展望 总被引:1,自引:0,他引:1
1923年,随着生殖腺反馈调节垂体功能的概念的提出,关于抑制素的研究开始了。抑制素是一种非类固醇类物质,能够抑制垂体细胞的活性。1932年,这种物质在水状的睾丸提取物中得到证实,并被命名为抑制素。又经过了50多年的研究,到1985年,抑制素才被纯化和克隆。而直到化验技术的进步使人和动物的循环浓度得以分析,抑制素的生理活性的揭示才得以完成。本文综述抑制素的历史、生理作用及其在辅助生殖技术中的最新的应用和研究。 相似文献
37.
目的 观察2型糖尿病妇女绝经期骨密度与甲状旁腺素、雌激素相关性研究.方法 测定绝经期2型糖尿病妇女伴骨质疏松(A)组及绝经期2型糖尿病妇女无骨质疏松(B)组的左侧髋部股骨颈、大转子、华氏三角区、及腰椎L2~L4正侧位的骨密度和血清中骨代谢指标,如:骨钙素、碱性磷酸酶、钙、磷、甲状旁腺素、雌二醇、Ⅰ型胶原羧基末端终肽(β-CTx)的浓度,对骨密度与多个变量之间的关系进行相关分析,并对(A)组血清中的甲状旁腺素、雌二醇、骨钙素、β-CTx与不同部位的骨密度之间的关系进行多元逐步回归分析.结果绝经期2型糖尿病妇女(B)组的腰椎、大转子、华氏三角区、股骨颈等骨密度指标明显低于对照组(A)(P<0.05);2型糖尿病绝经期妇女血清中雌二醇水平与腰椎L2~L4骨密度呈正相关(P<0.032);甲状旁腺素水平与股骨颈骨密度呈负相关(P<0.034).结论 绝经期2型糖尿病患者甲状旁腺素和雌激素水平与骨密度密切相关,分别可以用于预测骨质疏松发生的不同部位. 相似文献
38.
JAE YOUNG JOUNG DONG GOO KANG HYUCK-JAE CHOI WEON SEO PARK HO KYUNG SEO JIN SOO CHUNG KANG HYUN LEE 《International journal of urology》2006,13(11):1451-1453
Abstract Gastrointestinal stromal tumor (GIST) is a recently described mesenchymal tumor that can develop in any portion of the gastrointestinal tract. The occurrence of a GIST in the urinary tract is rare, but GIST can present as tumor of the urinary tract or invade the urinary tract. This is the first reported case of GIST in the ileal neobladder, which presented as a submucosal tumor. The patient underwent an open exploration and partial resection of the neobladder pouch. 相似文献
39.
Gonadotropins mediate DNA synthesis and protection from spontaneous cell death in human ovarian surface epithelium 总被引:2,自引:0,他引:2
R.J. EDMONDSON J.M. MONAGHAN & B.R. DAVIES† 《International journal of gynecological cancer》2006,16(1):171-177
Gonadotropins have been implicated in the development of epithelial ovarian cancers. These tumors are derived from ovarian surface epithelium (OSE). The purpose of this study was to determine the effects of these hormones on DNA synthesis and spontaneous cell death in primary cultures of OSE and three immortalized OSE cultures. Primary cultures of OSE cells were generated from the ovaries of women with benign disease. The effects of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on DNA synthesis and cell death were determined using [(3)H]thymidine incorporation and JAM assays. Significant inductions of DNA synthesis were demonstrated with LH in 4/12 (33%) primary cultures of OSE and 2/3 OSE cell lines and with FSH in 4/11 (36%) primary cultures of OSE and 2/3 OSE cell lines. A significant protection from cell death was also observed in the presence of FSH in 2/4 primary cultures of OSE and 1/3 OSE cell lines and in the presence of LH in 1/4 primary cultures of OSE and 2/3 OSE cell lines. The results indicate that while gonadotropins have the potential to induce cell proliferation and protect from cell death in OSE cells in vitro, their effects are variable in OSE cells from different women. 相似文献
40.
The differences between the postprandial mixing or propulsion and the interdigestive motility of the gastrointestinal (GI)
tract are already known. Earlier studies showed dose-dependent differences in the effects of erythromycin on interdigestive
motility. The various GI side-effects (vomiting, diarrhoea) also suggest that there are different effects of erythromycin
on the GI motility. The aim of our study was to examine postprandially the propulsive effects of different doses of erythromycin
on the movement of intraluminal contents in the upper GI tract of the rat. The animals were fasted for 24 h before the experiments
but water was given freely. The rats received 1.5 ml 1.5% methylcellulose painted with 0.05% phenol-red intragastrically (test
solution). Erythromycin(E. lactobionate) was given intravenously at doses of 0.05, 0.1, 0.25, 0.5, 1.0 and 5.0 mg/kg 15 min before the administration of a test solution.
The animals were sacrificed 20,60 and 120 min after administration of methylcellulose, when the distance between the front
of the painted intraluminal contents and the pylorus was measured and expressed as a percentage of the total length of small
intestine. The phenol-red content in the stomach and small intestine was measured spectrophotometrically and the gastric emptying
was calculated from the ratio of the measured total and intestinal phenol-red content. Our results showed that the small doses
of erythromycin (0.1 and 0.25 mg/kg) accelerated gastric emptying after 20 min but did not change significantly the propulsive
motility of upper small intestine; however, large doses of erythromycin (1.0 and 5.0 mg/kg) decreased gastric emptying and
upper GI motility after 20 and 60 min. In summary, the prokinetic action of small doses of erythromycin was demonstrated,
but its effecttime on GI motility is short and the ratio of the stimulating and inhibitory doses is 1:10.
This paper was presented at the Section of IUPHAR GI Pharmacology Symposium on ’Biochemical pharmacology as an approach to
gastrointestinal disorders (basic science to clinical perspectives)‘, October 12-14, 1995, Pécs, Hungary. 相似文献