全文获取类型
收费全文 | 30026篇 |
免费 | 1526篇 |
国内免费 | 696篇 |
专业分类
耳鼻咽喉 | 328篇 |
儿科学 | 653篇 |
妇产科学 | 1117篇 |
基础医学 | 7996篇 |
口腔科学 | 704篇 |
临床医学 | 1834篇 |
内科学 | 3022篇 |
皮肤病学 | 512篇 |
神经病学 | 1731篇 |
特种医学 | 588篇 |
外科学 | 1596篇 |
综合类 | 3015篇 |
预防医学 | 3505篇 |
眼科学 | 310篇 |
药学 | 3244篇 |
3篇 | |
中国医学 | 310篇 |
肿瘤学 | 1780篇 |
出版年
2023年 | 263篇 |
2022年 | 522篇 |
2021年 | 716篇 |
2020年 | 720篇 |
2019年 | 682篇 |
2018年 | 721篇 |
2017年 | 801篇 |
2016年 | 780篇 |
2015年 | 905篇 |
2014年 | 1683篇 |
2013年 | 1737篇 |
2012年 | 1547篇 |
2011年 | 1876篇 |
2010年 | 1452篇 |
2009年 | 1502篇 |
2008年 | 1563篇 |
2007年 | 1440篇 |
2006年 | 1286篇 |
2005年 | 1076篇 |
2004年 | 961篇 |
2003年 | 890篇 |
2002年 | 645篇 |
2001年 | 640篇 |
2000年 | 608篇 |
1999年 | 553篇 |
1998年 | 556篇 |
1997年 | 522篇 |
1996年 | 544篇 |
1995年 | 554篇 |
1994年 | 525篇 |
1993年 | 438篇 |
1992年 | 420篇 |
1991年 | 354篇 |
1990年 | 322篇 |
1989年 | 283篇 |
1988年 | 257篇 |
1987年 | 207篇 |
1986年 | 169篇 |
1985年 | 250篇 |
1984年 | 238篇 |
1983年 | 148篇 |
1982年 | 140篇 |
1981年 | 131篇 |
1980年 | 117篇 |
1979年 | 106篇 |
1978年 | 78篇 |
1977年 | 65篇 |
1976年 | 55篇 |
1974年 | 38篇 |
1973年 | 35篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
短发夹状RNA对PC-3M细胞端粒酶逆转录酶基因表达和端粒酶活性的影响 总被引:3,自引:0,他引:3
目的:研究短发夹状RNA(shRNA)对PC 3M细胞中端粒酶逆转录酶(hTRT)基因表达及端粒酶活 性的影响。方法:构建针对hTRT基因的shRNA表达质粒psilencer TRT,在质脂体介导下转染人前列腺癌PC 3M细胞,应用RT PCR及免疫组织化学检测hTRTmRNA及蛋白表达水平,应用SYBR Green染色法检测端粒 酶活性的变化。结果:重组体psilencer TRT转染细胞24h和48h后显著下调hTRTmRNA及蛋白水平,作用 48h后,其抑制率分别为85.39%和79.17%,较空白对照组差异有统计学意义(P<0.01)。同时,随着时间的延 长,端粒酶活性亦有明显下降(P<0.01)。结论:利用短发夹状RNA干扰技术能有效抑制靶基因的表达,为前 列腺癌的基因治疗提供新思路。 相似文献
53.
Decreased expression of DMPK: correlation with CTG repeat expansion and fibre type composition in myotonic dystrophy type 1 总被引:2,自引:0,他引:2
S. Salvatori M. Fanin C. P. Trevisan S. Furlan S. Reddy J. I. Nagy C. Angelini 《Neurological sciences》2005,26(4):235-242
Abstract Myotonic dystrophy type 1 (DM1) is an autosomal dominant disease caused by a trinucleotide repeatexpansion, cytosine-thymine-guanine
(CTG)n, in the 3′ untranslated region of a gene encoding the myotonic dystrophy protein kinase (DMPK). To correlate CTG expansion
and protein expression, we studied muscle specimens from 16 adult DM1 patients using three anti-DMPK antibodies for immunoblotting.
We estimated the amount of the full-length DMPK (85 kDa) in muscle biopsies from normal controls and from DM1 patients carrying
different (CTG)n expansions. We found that DMPK concentration was decreased to about 50% in DM patients’ muscles; the protein decrease did
not seem correlated with the CTG repeat length. However, the fibre type composition in skeletal muscle seemed somehow to affect
DMPK decrease, as the lowest level of the enzyme was found in patients with the lowest content of type 1 fibre. 相似文献
54.
Md. Kabirul Islam 《Indian journal of pediatrics》2002,69(10):819-820
An interesting case of a child with a tail is reported. The child had a tail like structure in the back since birth, increasing
with age. It was 20 cm. long, the longest tail so far described in the English literature. There was no functional complain.
The result was excellent after excision as the problem was only cosmetic. 相似文献
55.
The thymus in seronegative myasthenia gravis patients 总被引:1,自引:0,他引:1
Summary In 5–10% of all patients with typical generalised myasthenia gravis (MG), serum antibody to the acetylcholine receptor (AChR) is undetectable. To determine whether these represent a distinct subgroup, we have compared the thymuses of 14 seronegatives, 70 seropositives and 12 non-myasthenic controls. By quantitative immunohistology on coded sections, the 7 seronegative samples were clearly distinguishable from the controls by the pronounced lymph node-type T-cell areas in the medulla. While these closely resembled those in the seropositive cases, germinal centres were significantly sparser, and total in vitro IgG production was disproportionately low (per B cell) in the 12 cases tested. Furthermore, specific anti-AChR production was never detected in any of these cultures. The data support the view that the medullary T-cell areas are the most consistent abnormalitiy in the MG thymus (though it may not be primary), and they strongly imply that seronegative and seropositive MG are distinct entities. 相似文献
56.
Demonstration of human papillomavirus types 6 and 11 in juvenile laryngeal papillomatosis by in-situ DNA hybridization 总被引:3,自引:0,他引:3
A study is reported in which an in situ hybridization technique for the demonstration of human papillomavirus (HPV) employing a biotin--streptavidin polyalkaline phosphatase complex has been successfully applied to formalin-fixed paraffin-processed tissue obtained from ten patients with juvenile laryngeal papillomatosis. In all cases, positive results were obtained for either HPV type 6 or 11. Normal vocal cord epithelium was negative. 相似文献
57.
胸腺肽增强狂犬病疫苗免疫效果的研究 总被引:4,自引:0,他引:4
目的 探索胸腺肽作为人用纯化Vero -细胞狂犬病疫苗佐剂的可能性。 方法 分为单针和多针狂犬疫苗免疫方案。单针免疫是用狂犬疫苗 1支加胸腺肽 1针免疫 ;多针免疫按常规五针免疫程序 (即 0、3、7、14、2 8d各注射1针 ) ,加胸腺肽组按三针免疫程序 (即 0、7、2 8d各注射 1针 ) ,实验小白鼠每只均以狂犬病疫苗 0 .2ml与胸腺肽混合后肌肉注射。 结果 单针免疫加入胸腺肽 ( 2mg/只 )后抗体效价高且抗体产生时间早 ,抗体水平显著高于疫苗组 (P <0 .0 1)。而且加入胸腺肽 ( 6mg/只 )后免疫三针可达到五针常规疫苗免疫效果。 结论 胸腺肽作为人用纯化Vero -细胞狂犬病疫苗的佐剂可减少免疫次数。 相似文献
58.
生长激素抗肝纤维化的作用及其机制 总被引:3,自引:0,他引:3
目的 探讨重组人生长激素 (rhGH)对肝硬化大鼠在肝功能、门静脉高压等方面的治疗作用及其可能的机制。方法 雄性SD大鼠建立肝硬化模型 ,随机分组 ,分别给予NS、rhGH (333ng/KgBW ,ip ,qd× 7d)处理。 结果 rhGH处理前后肝硬化肝组织GHR的配体结合容量 [fmol/mg ,(31± 4 )vs .(4 0± 7) ]及其mRNA量 (iOD ,pixel)均显著升高 (2 3± 3)vs.(4 2± 8) ;P <0 0 5 ,肝硬化大鼠血清白蛋白 (g/L )显著升高 (2 9± 4 )vs .(37± 7) ;P <0 0 5、ALT活性 (U/L)显著降低 (89± 15 ,6 9± 7;P <0 0 5 ) ,肝硬化肝组织丙二醛含量 (nmol/mg)显著降低 (18 7± 3 2 ,12 0± 2 2 ;P <0 0 5 )、超氧化物歧化酶活性 (U/mg)显著升高 (82 4± 10 8,10 2 9± 76 ;P <0 0 5 )、胶原纤维相对含量 (% )显著降低 (2 2 30± 3 86vs.14 70± 2 0 7;P <0 0 5 ) ,肝硬化大鼠的门静脉压 (cmH2 O)亦显著降低 (14 4± 2 0vs.9 3± 1 5 ;P <0 0 5 )。结论 药理剂量的rhGH能够促进肝硬化大鼠的白蛋白合成、改善肝细胞功能 ,有助于抑制肝组织纤维化、缓解门静脉压力。 相似文献
59.
Kathleen A. Ward Sinead A. McKernan Natalina N. Durnien Wallace W. Dinsmore 《Journal of the European Academy of Dermatology and Venereology》1995,4(2):160-165
Objective Detection of HPV DNA in oral and genital lesions of a heterosexual male. 4 months after oral and vaginal intercourse with a woman with vulvar warts. Passible modes of acquisition of oral HPV infection in the male sexual partner are discussed. Setting Genitourinary Medicine clinic. Methods Polymerase chain reaction amplification of genomic DNA from oral and genital lesions. HPV DNA typing by dot blot hybridization. Results HPV DNA types 6 and 11 were identified in a polypoid tongue lesion and in a penile wart from the male sexual partner. Conclusions The acquisition of oral HPV infection in the male sexual partner may have resulted from genital-oral HPV transfer, either by direct contact with vulvar warts or by digital self-inoculation. 相似文献
60.
Objective To investigate the correlation between human epidermal stem cell (hESCs) and hypertrophic scar or keloid. Methods Improved collagen Ⅳ-coated adhesion methods was used to isolate and culture the epidermal stem cells after neutral protease selectively digested the dermo-epidermal junctions. After the cells were cultured and expanded in vitro, and passage 3 hESCs were induced by different concentrations of TGF-β1 (0.1, 5.0, and 10.0 ng/ml). Morphological fea-tures and identification of these cells were meseasured by HE, Masson, immunohistochemical staining on the days 3 and 7, respectively. Results After induced by TGF-β1 for 3 and 7 days, the morpholo-gy of the epidermal stem cell (hESCs) was changed into fusiform shape, similar to fibroblasts. 70 % ofthe cell which was induced by TGF-β1 were blue stained in the cytoplasm by Masson stain, which is the distinctive method for collagen, suggesting collagen appeared or increased in the cells. The collagen concentrations in supernatants of hESCs were 0.4150±0.0014, 0.3380±0. 0020, and 0.3870±0.0020, much higher than that in control group (0.0780±0.0025) and normal skin fibro-blast group (0.15004±0.0051) (P<0.05). Immunohistochemical staining revealed that positive rates of these cells for anti-vimentin staining were more than (95.00±1.20)% in experiments and (5.70±0.20)% in control group. Conclusion The differentiantion of hESCs induced by TGF-β1 into fibro-blasts indicates that hESCs may play a role in the pathogenesis of hypetrophic scar and keloid. 相似文献