全文获取类型
收费全文 | 537777篇 |
免费 | 50103篇 |
国内免费 | 35603篇 |
专业分类
耳鼻咽喉 | 4300篇 |
儿科学 | 7028篇 |
妇产科学 | 6009篇 |
基础医学 | 63110篇 |
口腔科学 | 9305篇 |
临床医学 | 72106篇 |
内科学 | 71152篇 |
皮肤病学 | 5817篇 |
神经病学 | 25163篇 |
特种医学 | 19578篇 |
外国民族医学 | 277篇 |
外科学 | 48580篇 |
综合类 | 100199篇 |
现状与发展 | 114篇 |
一般理论 | 43篇 |
预防医学 | 40206篇 |
眼科学 | 14409篇 |
药学 | 60086篇 |
597篇 | |
中国医学 | 34828篇 |
肿瘤学 | 40576篇 |
出版年
2024年 | 1963篇 |
2023年 | 7843篇 |
2022年 | 20503篇 |
2021年 | 25966篇 |
2020年 | 20167篇 |
2019年 | 16304篇 |
2018年 | 17251篇 |
2017年 | 16646篇 |
2016年 | 15313篇 |
2015年 | 23657篇 |
2014年 | 29618篇 |
2013年 | 27998篇 |
2012年 | 40881篇 |
2011年 | 44997篇 |
2010年 | 31387篇 |
2009年 | 25734篇 |
2008年 | 30822篇 |
2007年 | 30657篇 |
2006年 | 28789篇 |
2005年 | 26704篇 |
2004年 | 18674篇 |
2003年 | 17831篇 |
2002年 | 14856篇 |
2001年 | 12586篇 |
2000年 | 11634篇 |
1999年 | 11099篇 |
1998年 | 6971篇 |
1997年 | 6843篇 |
1996年 | 5227篇 |
1995年 | 4899篇 |
1994年 | 4222篇 |
1993年 | 2784篇 |
1992年 | 3391篇 |
1991年 | 2984篇 |
1990年 | 2590篇 |
1989年 | 2258篇 |
1988年 | 1907篇 |
1987年 | 1730篇 |
1986年 | 1470篇 |
1985年 | 1093篇 |
1984年 | 739篇 |
1983年 | 573篇 |
1982年 | 407篇 |
1981年 | 396篇 |
1980年 | 312篇 |
1979年 | 347篇 |
1978年 | 265篇 |
1977年 | 264篇 |
1976年 | 225篇 |
1974年 | 198篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
TRH、EGF及地塞米松促进未成熟胎肺组织分化及表面活性物质合成的研究 总被引:5,自引:3,他引:2
目的 比较TRH、EGF与地塞米松对未成熟胎肺形态发育及表面活性物质水平的影响。方法 在兔妊娠第22-24d或第24-26d分别用TRH、EGF或地塞米松母体静脉注射治病,通过光镜、图像分析及电镜等技术观察胎肺的形态结构,并检测胎肺的磷脂水平。结果 光镜下,TRH、EGF与地塞米松治疗组第25d及27d胎肺肺泡腔、肺泡间隔发育均明显好于对照组;EGF、TRH与地塞米松治疗组第27d胎肺的肺泡腔与肺泡间隔的面积比无明显差异。但EGF和TRH治疗组第25d胎肺的肺泡腔与肺泡间隔之比明显小于地塞米松治疗组。电镜下,三个治疗组第27d胎肺内含有板层体的Ⅱ型上皮细胞数量明显多于对照组,但各治疗组及对照组第25d的胎肺Ⅱ型上皮细胞胞浆内几乎未见明显板层体,相反胞浆内糖原含量却非常丰富。此外,三个治疗组27d胎肺的磷脂水平均明显高于对照组。结论 EGF、TRH及地塞米松在兔妊娠第24-26d母体治疗均能促进胎肺的形态发育和表面活性物质的合成,三种治疗方法对胎肺的影响程序无明显不同;在妊娠第22-24d治疗,地塞米松对胎肺形态结构的促进作用较EGF和TRH更明显,但三者对Ⅱ型上皮细胞分化及表面活性物质的合成均无明显影响。 相似文献
82.
No impact of repeated endoscopic screens on gastric cancer mortality in a prospectively followed Chinese population at high risk. 总被引:6,自引:0,他引:6
B Riecken R Pfeiffer J L Ma M L Jin J Y Li W D Liu L Zhang Y S Chang M H Gail W C You 《Preventive medicine》2002,34(1):22-28
BACKGROUND: Gastric cancer (GC) is the leading cause of cancer deaths in China. Our study prospectively evaluated the impact of repeated endoscopic screens on GC mortality in a high-risk population in China. METHODS: Between 1989 and 1999, a population-based gastroscopic screening was conducted in 4,394 residents of Linqu County, China, a region with the highest rates of GC worldwide. Residents ages 35 to 64 years received initial gastroscopies with biopsies in 1989. Repeated endoscopies were performed in 1994 and 1999. Cancer occurrences and deaths were actively monitored throughout the entire period until July 2000. Mortality from GC was compared with expected values based on mortality rates obtained for Linqu in the 1990-1992 Chinese Cancer Mortality Survey. RESULTS: Between March 1989 and July 2000, 39,303 person-years were accumulated; 85 new GCs occurred, 29 (34.5%) were in early stage. Fifty-eight cases (68%) were identified at one of the screens. The number of observed deaths from GC (37) was close to the expected (36.8). The standardized mortality ratio was 1.01 (95% CI 0.72-1.37) for the entire cohort, 1.13 (95% CI 0.77-1.57) for males, and 0.65 (95% CI 0.26-1.32) for females. CONCLUSIONS: Despite high population coverage with repeated screens, no reduction in GC mortality was observed in this high-risk population in China. 相似文献
83.
李永光 《中国民族医药杂志》2005,11(6):21-21
蒙医学在长期的临床实践中总结和探索出较为科学的毒性药物炮制、制剂配伍和应用方法,使毒性药物在临床得到极为广泛的应用。特别是蒙药一般选用生药、多复方、用量小、服用方法简便、起效迅速,其作用较等量中药制剂强而有力,其中重要原因之一就是蒙医学擅长使用毒性药物及峻烈药材,以毒攻毒,多有奇效。成方中含有毒药物的方剂比率较高,据《蒙医成方选》一书记载:解痉镇痛药全部8个配方,白喉肿毒治疗药配方24个中有20个, 相似文献
84.
白纹伊蚊在竹林里孳生的阳性比为75.4%;而在竹林包围的居民区阳性比为15.3%。白纹伊蚊在居民区孳生密度布雷图指数为19.4,容器指数为6.2%。居民区孳生蚊虫的主要场所是泡菜坛,泡菜坛主要孳生蚊种是骚扰阿蚊,阳性比为73.7%,其次是淡色库蚊为20.2%,贪食库蚊为14.0%,白纹伊蚊最低,为9.1%。 相似文献
85.
目的分析各种因素对手工凝聚胺试验的影响;方法应用手工凝聚胺(manual polgbrene test,MPT)做交叉配血及抗体筛选试验;结果血液标本、操作手法、凝聚胺试剂、药物(肝素、止血敏、高浓度KCl等)等对试验均有影响;其中以药物、操作手法影响较大,可致假阴性和假阳性结果;结论手工凝聚胺试验做交叉配血及抗体筛选时应注意排除药物和操作手法对试验结果的影响。 相似文献
86.
The neuroprotective effects of dizocilipine maleate (MK-801), a noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptor/channel, were tested in the 4-vessel occlusion rat model of forebrain ischemia. Adult Wistar rats, treated intraperitoneally with MK-801 or saline using several different treatment paradigms were subjected to 5 (n = 208) or 15 (n = 62) min of severe, transient forebrain ischemia. In saline-treated animals, 15 min of ischemia (n = 13) produced extensive and consistent loss of pyramidal neurons in the CA1 zone of hippocampus. The degree and distribution of cell loss were not reduced by single dose preischemic administration of MK-801 at 1 (n = 7), 2.5 (n = 4), or 5 mg/kg (n = 8). In other animals subjected to 15 min of forebrain ischemia, multiple doses of MK-801 (5, 2.5, and 2.5 mg/kg) given immediately and at approximately 8 and 20 hr after cerebral reperfusion (n = 5) did not alter CA1 injury compared to saline-treated controls (n = 5). Five minutes of forebrain ischemia in saline-treated animals, (n = 82) resulted in significantly fewer (p less than 0.001) dead CA1 pyramidal cells and a greater variance compared to animals subjected to 15 min of ischemia. Power analysis of the preliminary saline-treated animals subjected to 5 min of ischemia (n = 22) indicated that 60 animals per group were necessary to detect a 15% difference between MK-801 and vehicle-treated groups. Multidose treatment with MK-801 (1 mg/kg) given 1 hr prior to 5 min of ischemia (n = 60) and again at approximately 8 and 16 hr after recirculation failed to attenuate hippocampal injury.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
87.
目的 探讨儿童颈椎间盘钙化症的影像表现及诊断价值,并提高对本病的认识。方法 回顾分析16例儿童颈椎钙化性椎间盘病的影像表现。结果 16例患均行颈椎平片检查,5例行CT扫描并作了三维重建,8例行MRI检查。16例平片均显示了椎间盘钙化灶,均为单发,CT平扫加三维重建显示4例钙化呈卵圆形,1例钙化为不规则形。MRI检查不仅显示了椎间盘内改变还清晰显示了病变相邻椎体边缘信号改变,在T1、T2加权像上呈低信号。结论 平片检查可以显示椎间盘钙化;CT平扫加三维重建能清晰显示了钙化灶的大小、形态;MRI检查在显示受累椎体及周围组织的改变方面明显优于CT和平片。 相似文献
88.
黎小妮 《中国中医药现代远程教育》2005,3(6):39-40
<银海指南>[1]又名<眼科大成>,为清·顾锡于1807年所著.该书以论述眼病的病因病机非常精辟而又详尽称著.其中论及全身病兼目疾又是该书的一大特色,其学术理念对后学深有影响.我们今天循着顾氏所提示的辨治线索,仍然感到有指导性意义. 相似文献
89.
Therapy of human cervical carcinoma with monoclonal antibody-Pseudomonas exotoxin conjugates. 总被引:1,自引:0,他引:1
Pseudomonas exotoxin A (PE) linked to the F(ab')2 fragment of 1H10, a murine monoclonal antibody recognizing a carbohydrate epitope of a glycoconjugate expressed on the surface of human cervical carcinoma tumor cells, was evaluated for in vitro and in vivo activity. PE can kill cells by ADP-ribosylating elongation factor 2 thus inhibiting protein synthesis. Disulfide- as well as thioether-linked immunotoxins (1H10-PE) killed cervical carcinoma cells in vitro and were 20-160 times more inhibitory to target than to control cells. Cell killing was antibody mediated as demonstrated by the reduction of 1H10-PE growth inhibition to target CaSki cells by free 1H10 F(ab')2. In addition, a control antibody immunotoxin was nontoxic to CaSki cells. Thioether-linked 1H10-PE administered either i.v. or i.p. suppressed the growth of established solid s.c. cervical carcinoma tumors xenografted in nude mice for over 30 days. Treatment with antibody alone or a control immunotoxin had no significant effect on tumor growth. Administration of immunotoxin i.p. was associated with less toxicity than administration i.v., but i.v. injections were more effective at suppressing the growth of established solid tumors. 相似文献
90.