全文获取类型
收费全文 | 59269篇 |
免费 | 5526篇 |
国内免费 | 4170篇 |
专业分类
耳鼻咽喉 | 662篇 |
儿科学 | 606篇 |
妇产科学 | 571篇 |
基础医学 | 6073篇 |
口腔科学 | 900篇 |
临床医学 | 7516篇 |
内科学 | 8017篇 |
皮肤病学 | 576篇 |
神经病学 | 2813篇 |
特种医学 | 2300篇 |
外国民族医学 | 37篇 |
外科学 | 6422篇 |
综合类 | 10960篇 |
现状与发展 | 13篇 |
一般理论 | 3篇 |
预防医学 | 4224篇 |
眼科学 | 1631篇 |
药学 | 6421篇 |
54篇 | |
中国医学 | 4203篇 |
肿瘤学 | 4963篇 |
出版年
2024年 | 272篇 |
2023年 | 906篇 |
2022年 | 2407篇 |
2021年 | 3031篇 |
2020年 | 2456篇 |
2019年 | 1912篇 |
2018年 | 2040篇 |
2017年 | 2029篇 |
2016年 | 1817篇 |
2015年 | 2926篇 |
2014年 | 3660篇 |
2013年 | 3354篇 |
2012年 | 4896篇 |
2011年 | 5208篇 |
2010年 | 3607篇 |
2009年 | 2921篇 |
2008年 | 3382篇 |
2007年 | 3129篇 |
2006年 | 3060篇 |
2005年 | 2830篇 |
2004年 | 1848篇 |
2003年 | 1754篇 |
2002年 | 1456篇 |
2001年 | 1194篇 |
2000年 | 1131篇 |
1999年 | 1068篇 |
1998年 | 664篇 |
1997年 | 607篇 |
1996年 | 491篇 |
1995年 | 463篇 |
1994年 | 351篇 |
1993年 | 260篇 |
1992年 | 315篇 |
1991年 | 313篇 |
1990年 | 212篇 |
1989年 | 167篇 |
1988年 | 185篇 |
1987年 | 155篇 |
1986年 | 104篇 |
1985年 | 80篇 |
1984年 | 60篇 |
1983年 | 34篇 |
1982年 | 30篇 |
1981年 | 31篇 |
1980年 | 24篇 |
1979年 | 38篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1975年 | 11篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Anatomic and spiral computed tomographic study of the genial tubercles for genioglossus advancement.
Shan Kai Yin Hong Liang Yi Wen Ying Lu Jian Guan Hong Min Wu Zhen Yu Cao Dong Zhen Yu Yan Yan Huang Chun Gen Wu 《Otolaryngology--head and neck surgery》2007,136(4):632-637
OBJECTIVE: To measure and compare Chinese mandibular genial tubercles measured anatomically and with computed tomography (CT). STUDY DESIGN AND SETTING: Spiral CT scans were taken of 40 adult human skulls; the superior genial spines were measured using anatomic and CT methods. RESULTS: The height and width of the superior genial spines, mandible thickness, and distance from the menton to the inferior and superior margins of the superior genial spines were 5.82 +/- 0.71, 6.98 +/- 1.35, 11.95 +/- 1.59, 11.08 +/- 2.05, and 16.91 +/- 2.30 mm from anatomic measurements and 6.17 +/- 0.71, 7.01 +/- 1.13, 12.19 +/- 1.64, 10.41 +/- 1.55, and 15.73 +/- 2.12 mm using spiral CT, respectively. The anatomic and CT measurements were correlated. CONCLUSION: Spiral CT of the genial tubercles can help locate the osteotomy in genioglossus advancement. SIGNIFICANCE: This study acquired reference data on Chinese genial tubercles demonstrating that CT measurements of the genial tubercles reflect their anatomy, which should allow accurately locate the osteotomy. 相似文献
42.
为比较盐酸二甲双胍和糖适平对Ⅱ型糖尿病的治疗效果,通过33例Ⅱ型糖尿病患者服用二甲双胍和35例Ⅱ型糖尿病患者服用糖适平,观察4mo后发现二甲双胍在降低血糖、24h尿糖定量,降低血脂及逆转外周神经病变方面有显著疗效。但二甲双胍不能升高血浆C—肽水平,不能降低24h尿蛋白质定量。如能将二甲双胍和糖适平联合应用将会提高疗效,减轻副作用。 相似文献
43.
Rapid identification of low level hepatitis B-related viral genome in serum. 总被引:6,自引:1,他引:5 下载免费PDF全文
A sensitive and specific method has been developed to detect hepatitis B virus (HBV) in serum. The method involves two steps: the capture of viral genome from serum using a high affinity IgM monoclonal antibody directed against a common a domain epitope found on the envelope, and the amplification of viral DNA by the polymerase chain reaction (PCR). The amplification is initiated using "generic" primers derived from the core and pre-core sequences which are highly conserved amongst the hepadnaviruses. This rapid technique detects less than 10 infectious virions and may be useful in the study of individuals with acute and chronic liver disease of unknown etiology. 相似文献
44.
目的 探讨新生儿C6PD缺陷病和晚发性维生素K缺乏症的危害与预防措施。方法 回顾分析1995-2000年儿内科住院的1周-2月(不含2月)的婴儿3104例次,其中病死56例。结果 1周-2月的小婴儿占住院患儿的19.34%,其中新生儿G6PD缺陷病239例,占7.70%;晚发性维生素K缺乏症92例,占2.96%。死因的第2、3位分别是晚发性维生素K缺乏症(13例,占23.21%)和新生儿C6PD缺陷病(12例,占21.43%),两者的病死率分别为14.13%和5.02%,极显著高于(x^2=17.59,P<0.01)或相近于(x^2=0.88,P>0.05)肺炎的3.57%。新生儿G6PD缺陷病合并感染占38.49%、低氧血症占23.35%、低血糖占19.25%、酸中毒占15.90%,继发胆红素脑病占13.81%。晚发性维生素K缺乏症出现抽搐占90.22%、胃肠、注射部位出血占60.89%;CT证实颅内出血占98.91%。结论 1周-2月的小婴儿约占住院患儿的两成,新生儿G6PD缺陷病和晚发性维生素K缺乏症的病死率均很高,两者是除肺炎外最主要的死因。提议制定并推广预防这2种疾病的常规措施,并参照国内外相应的现状拟出其具体内容。 相似文献
45.
人FascDNA的克隆及其在大肠杆菌中表达的研究 总被引:1,自引:1,他引:1
为获得高质量及充足的Fas蛋白,采用PCR技术调整Fas基因的开放阅读框架,使之与生物素化蛋白基因阅读框架一致;缺失了FascDNA基因的起始密码子并增加一个大肠杆菌偏性终止密码子,构建FascDNA和生物素化融合原核表达质粒PinPoint-Fas。将重组质粒转入大肠杆菌HB101,经500mmolIPTG在37℃条件下诱导4h,SDS-PAGE及Western印迹检测融合蛋白在大肠杆菌得以高效表达,表达量为细菌总蛋白的13.8%。用亲和层析树脂对生物素化融合蛋白进行亲和层析纯化,得到Fas重组的蛋白,且表达的Fas融合蛋白具有抗体结合活性。此蛋白的表达成功将解决Fas膜蛋白不易提取的难题,为深入研究Fas提供了良好材料来源 相似文献
46.
47.
Owada-Makabe K Tsubota Y Yukawa K Kakimoto N Liang XM Ichinose M Maeda M 《Neuroscience letters》2005,378(1):18-21
Attempts at protein transduction into specific restricted brain areas have remained unsuccessful. We attempted targeted, direct in vivo protein transduction by microinjecting beta-galactosidase (beta-gal) with hemagglutinating virus of Japan envelope (HVJ-E) vector into the rat nucleus tractus solitarius (NTS). The medulla oblongata including the NTS was removed 6h post-injection and cryostat sections were histochemically stained to detect beta-gal enzymatic activity. beta-gal-positive cells were present in these sections as was beta-gal activity determined by colorimetric analysis. beta-gal-positive cells were not present in the rats microinjected only beta-gal protein without HVJ-E vector. Our findings suggest that direct in vivo protein transduction into specific restricted brain areas is possible. The type of targeted delivery system we present may have wide applications in the administration of therapeutic proteins to the central nervous system. 相似文献
48.
在心室晚电位的研究中,我们引入了信号的时间一频率表示法,并根据晚电位的具体特性用Wigner分布法(维格纳分布)把信号表示为在时间及频率空间中的能量分布。由于Wigner分布的优异性质使我们有可能更准确表示出心室晚电位的存在。但当输入信号是两个信号的线性叠加时,Wigner分布的结果会出现一个交叉项,相当于引入干扰。针对此不足,作者介绍改进方案,消除部分交叉项,收到较好的效果,并给出一些仿真及应用实例。 相似文献
49.
Ma HP Zhou ZH Liang YY Saxena S Warnock DG 《Pflügers Archiv : European journal of physiology》2004,449(1):96-105
Using whole-cell patch-clamp techniques we found that ATP activated an outwardly rectifying current in Daudi human B lymphoma cells under acidic conditions. The substitution of Cl– for gluconate– shifted the reversal potential, while Cl– channel blockers, 4,4-diisothiocyanostibene-2,2-disulfonic acid (DIDS) and 9-anthracene carboxylic acid (9-AC), blocked the current, indicating that ATP induces this current by activating the outwardly rectifying chloride channel (ORCC). The effect of ATP on ORCC was mimicked by ADP, but not by other P2 receptor agonists such as ATPS (a poorly hydrolyzable analog of ATP), 2,3-O-benzoyl-4-benzoyl-ATP (BzATP), and UTP. The ATP-induced ORCC current was completely blocked by 100 M suramin (a P2 receptor antagonist), and was partially blocked by 100 M pyridoxal-phosphate-6-azophenyl-2,4-disulfonic acid tetrasodium (PPADS), which is another P2 receptor antagonist. Neither inactivation of G proteins nor elimination of extracellular Ca2+ affected the ATP-induced current, indicating that G protein-coupled P2Y receptors and Ca2+-permeable P2X receptors are not involved. Based on the pharmacological profile and the fact that acidic conditions are required for ATP to activate the ORCC, we suggest that acidic ATP activates the lymphocyte ORCC via a novel pathway, which is not associated with any previously described purinergic receptors. 相似文献
50.
Molecular cloning and sequence analysis of full-length cDNAs encoding new group of Cyn d 1 isoallergens 总被引:3,自引:0,他引:3
BACKGROUND: Cyn d 1, the major allergen of Bermuda grass pollen, contains some acidic/basic isoforms. The N-terminal amino acid sequences of some acidic Cyn d 1 isoforms were found to be different from those of Cyn d 1 cDNA clones identified previously. METHODS: A predicted 17-meric oligonucleotide probe was designed to fish the unidentified isoallergen cDNAs out of BGP cDNA library. The reactive clones were isolated and verified by sequencing. Two of them were expressed in the yeast Pichia pastoris to obtain recombinant Cyn d 1 proteins. RESULTS: All four cDNA clones encode the full-length Cyn d 1 with mature proteins of 244 amino acid residues. A 97-99% identity was found among the deduced amino acids of these four clones while an 86% identity was elicited between the four clones and the ones previously identified. The predicted isoelectric focusing (pI) values of the newly identified Cyn d 1s are acidic while pIs of the previously identified Cyn d 1s are basic. The two recombinant acidic Cyn d 1 proteins possess the epitopes recognized by mouse and rabbit polyclonal anti-Cyn d 1 antibodies, and have human IgE-binding capacity as revealed by immunodot assay. CONCLUSIONS: The present study identified full-length cDNAs encoding new isoallergens of Cyn d 1, and separated Cyn d 1 gene into an acidic group and a basic group. 相似文献