全文获取类型
收费全文 | 280篇 |
免费 | 15篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 7篇 |
妇产科学 | 13篇 |
基础医学 | 40篇 |
口腔科学 | 6篇 |
临床医学 | 31篇 |
内科学 | 52篇 |
皮肤病学 | 22篇 |
神经病学 | 23篇 |
特种医学 | 8篇 |
外科学 | 22篇 |
综合类 | 3篇 |
预防医学 | 18篇 |
眼科学 | 16篇 |
药学 | 19篇 |
中国医学 | 1篇 |
肿瘤学 | 10篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 12篇 |
2019年 | 15篇 |
2018年 | 15篇 |
2017年 | 9篇 |
2016年 | 10篇 |
2015年 | 14篇 |
2014年 | 18篇 |
2013年 | 17篇 |
2012年 | 21篇 |
2011年 | 27篇 |
2010年 | 19篇 |
2009年 | 5篇 |
2008年 | 15篇 |
2007年 | 12篇 |
2006年 | 16篇 |
2005年 | 10篇 |
2004年 | 11篇 |
2003年 | 6篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有295条查询结果,搜索用时 15 毫秒
1.
Krishna SM James S Kattoor J Balaram P 《Indian journal of pathology & microbiology》2004,47(2):181-185
Nasopharyngeal carcinoma (NPC) is a rare malignancy world-wide. It shows an increasing trend in the southern parts of India. Genetic alterations brought about by environmental factors, HPV and EBV are thought to be crucial for NPC carcinogenesis. This study reports for the first time the incidence of HPV infection in NPC in Southern India. Detection of HPV was carried out in 36 NPC and 10 adenoid lesions by immunohistochemical analysis. 38.8% of NPC were positive for HPV with higher positivity in WHO Type I and WHO Type II cancers. One among 10 adenoid lesions also showed presence of HPV. The patients belonged to low socio-economic status and had exposure to either tobacco or alcohol alone or in combination or kitchen smoke. 相似文献
2.
3.
Vishnu Prasad Pulappadi Smita Manchanda Pritviraj SK Smriti Hari 《The British journal of radiology》2021,94(1117)
Corpus luteum rupture presenting as acute abdomen is an underdiagnosed condition. Though a self-limiting entity, its differentiation from other causes is essential to prevent unnecessary surgical procedures. The radiologist should be aware of the possibility of a ruptured haemorrhagic ovarian cyst in a female of reproductive age group presenting with pelvic pain and a large amount of haemorrhagic ascites. Imaging characteristically reveals a thick-walled cystic structure in the adnexa with internal echoes, focal discontinuity or irregularity of its wall with haemoperitoneum. While sonography is usually indicative of corpus luteum rupture, cross-sectional imaging (CT/MRI) can be used to confirm the diagnosis. 相似文献
4.
Ruchi Goel Saurabh Kamal Sonam A. Bodh Sushil Kumar Jugal Kishore K.P.S. Malik Madhu Singh Smriti Bansal 《Journal of cranio-maxillo-facial surgery》2013,41(7):e111-e116
ObjectiveTo evaluate the efficacy and complications of lower eyelid suspension with the modified Safdarjung hospital technique using 5:0 polypropylene suture for punctal ectropion.Study designProspective case series.MethodThirty one eyelids in 19 patients with mild and moderate ectropion and all types of laxity including involutional and paralytic were included. All patients underwent lower eyelid suspension with the modified Safdarjung hospital technique. A 5:0 polypropylene suture was passed in the pre-tarsal plane between the attachments of the lateral and medial canthal tendons near their insertion at the orbital rim. Successful outcome was judged by the anatomical restoration of the apposition of the punctum to the globe in the upward gaze and the physiological relief of epiphora. The recurrence of lid laxity, overall lid/globe apposition and complications were also noted.ResultsAt 1 year follow up anatomical success was achieved in 28 (90%) patients and functional success noted in 27 (87%) patients. Recurrence of lid laxity was noted in 2 patients. There was a suture exposure in one case and a suture granuloma in another case. The results did not correlate to the degree of ectropion and type of laxity.ConclusionLower eyelid suspension using 5:0 polypropylene suture is a useful procedure for the treatment of involutional and paralytic punctal ectropion. It is simple and effective with minimal complications. However, the effect on scleral show and the concern related to suture material biodegradation over years needs to be further evaluated. 相似文献
5.
Smriti Kala Nichole Cumby Paul D. Sadowski Batool Zafar Hyder Voula Kanelis Alan R. Davidson Karen L. Maxwell 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(16):6022-6027
The genome packaging reactions of tailed bacteriophages and herpes viruses require the activity of a terminase enzyme, which is comprised of large and small subunits. Phage genomes are replicated as linear concatemers composed of multiple copies of the genome joined end to end. As the terminase enzyme packages the genome into the phage capsid, it cleaves the DNA into single genome-length units. In this work, we show that the phage HK97 HNH protein, gp74, is required for the specific endonuclease activity of HK97 terminase and is essential for phage head morphogenesis. HNH proteins are a very common family of proteins generally associated with nuclease activity that are found in all kingdoms of life. We show that the activity of gp74 in terminase-mediated cleavage of the phage cos site relies on the presence of an HNH motif active-site residue, and that the large subunit of HK97 terminase physically interacts with gp74. Bioinformatic analysis reveals that the role of HNH proteins in terminase function is widespread among long-tailed phages and is uniquely required for the activity of the Terminase_1 family of large terminase proteins.Tailed bacteriophages and herpes viruses package their large double-stranded DNA genomes into a preformed protein shell, known as the “prohead,” using terminase enzymes. In both types of viruses, the genome is synthesized as concatemers composed of multiple copies of the genome joined end to end. This concatemeric DNA is packaged into the prohead and cleaved into genome-length units by terminase in an ATP-dependent reaction. Phage terminases are composed of two proteins: the large subunit harbors an endonuclease domain and an ATPase that powers the DNA packaging reaction, and the small subunit mediates specific DNA-binding required for recognition of packaging sites in the phage genome. A variety of elegant structural and biophysical studies have recently provided insight into the molecular mechanisms of terminase function (1, 2). However, the factors that affect the action of terminase enzymes in vivo have been less well characterized.Terminase enzymes perform several functions. They specifically recognize and bind the viral genome, interact with the prohead, then drive the DNA into the head through the narrow entry channel formed by the portal protein that is positioned at a single vertex of the head. During this process terminases also cleave the viral DNA, either nonspecifically upon head filling or at a specific site known as “cos.” The efficient packaging of a phage genome in vivo may require phage-encoded cofactors in addition to the terminase enzyme. For example, Escherichia coli phage λ gpFI facilitates interaction of the terminase–DNA complex with proheads (3–6). A wide variety of phages appear to encode proteins with a function similar to λ gpFI (7). Additionally, the activity of Bacillus subtilis phage phi29 terminase requires a phage-encoded RNA molecule bound to its portal protein (8), and in vivo packaging of the E. coli phage T4 genome can only be completed with the participation of the phage-encoded endonuclease, gp49 (9). The general prevalence and importance of terminase cofactors is difficult to evaluate because few studies have addressed this issue.We recently reported that phage genomes often encode proteins possessing an HNH motif near their terminase genes (10). The HNH motif is ∼35 aa long, and is characterized by the presence of two highly conserved His residues and one Asn residue. These HNH motifs, as defined by the large (∼7,400-member) HNH Pfam (11) protein sequence family (PF01844), are often found in proteins that possess endonuclease activity, such as site-specific homing endonucleases (12, 13), colicins (14, 15), S pyocins (16), and restriction enzymes (17–19). HNH motif-containing proteins comprised of primarily an HNH motif as found in E. coli colicins, usually possess nonspecific endonuclease activity. Conversely, HNH motif-containing proteins may contain DNA-recognition domains in addition to the HNH motif and thus possess high sequence specificity, as found in the homing endonucleases.The frequent juxtaposition of HNH and phage terminase genes (10, 20) suggests a unique role for HNH proteins in the endonuclease and/or packaging activities of the terminases. To address this issue, we investigated the function of E. coli phage HK97 gp74, a 119-residue protein containing an HNH motif. The gene encoding gp74 is located at the extreme 3′ end of the mature linear HK97 genome, adjacent to the cos site. In both the lysogen and replicative form of the HK97 genome gene 74 is immediately adjacent to genes 1 and 2, which encode the small and large subunits of terminase (TerS and TerL), respectively. Whereas gp74 was previously found to possess endonuclease activity (10), its role in the HK97 replication cycle remained uncharacterized. In this study we used functional and bioinformatic analyses to investigate its function. 相似文献
6.
7.
8.
Nicholas Jones Marcus J Messenger Michael J O'Neill Anna Oldershaw Gary Gilmour Rosa M A Simmons Smriti Iyengar Vincenzo Libri Mark Tricklebank Steve C R Williams 《Neuropsychopharmacology》2008,33(7):1713-1723
We present a substantial series of behavioral and imaging experiments, which demonstrate, for the first time, that increasing AMPA receptor-mediated neurotransmission via administration of potent and selective biarylsulfonamide AMPA potentiators LY404187 and LY451395 reverses the central effects of an acutely intoxicating dose of ethanol in the rat. Using pharmacological magnetic resonance imaging (phMRI), we observed that LY404187 attenuated ethanol-induced reductions in blood oxygenation level dependent (BOLD) in the anesthetized rat brain. A similar attenuation was apparent when measuring local cerebral glucose utilization (LCGU) via C14-2-deoxyglucose autoradiography in freely moving conscious rats. Both LY404187 and LY451395 significantly and dose-dependently reversed ethanol-induced deficits in both motor coordination and disruptions in an operant task where animals were trained to press a lever for food reward. Both prophylactic and acute intervention treatment with LY404187 reversed ethanol-induced deficits in motor coordination. Given that LY451395 and related AMPA receptor potentiators/ampakines are tolerated in both healthy volunteers and elderly patients, these data suggest that such compounds may form a potential management strategy for acute alcohol intoxication. 相似文献
9.
10.
Khera S Woldemichael GM Singh MP Suarez E Timmermann BN 《Journal of natural products》2003,66(12):1628-1631
Bioassay-guided fractionation of the antibacterial CH(2)Cl(2)-MeOH extract obtained from the aerial parts of the Argentinean plant Caiophora coronata led to the isolation of a new triterpene, 1beta,3beta-dihydroxyurs-12-en-27-oic acid, 1, and a new iridoid, 1alpha-methoxy-6alpha,10-dihydroxyisoepiiridomyrmecin (caiophoraenin), 2, along with the known iridoid isoboonein 3. Their structures were established by spectroscopic techniques (1D and 2D NMR, HRFABMS, FTIR). The MIC values of isolated compounds were determined against methicillin-sensitive (MSSA) and -resistant (MRSA) strains of Staphylococcus aureus, Bacillus subtilis (BS), vancomycin-resistant Enterococcus faecium (VREF), Escherichia coli (EC), E. coli imp (ECimp), and Candida albicans (CA). Compound 1 was found active against BS, MSSA, MRSA, VREF, and ECimp with MIC values of 2, 4, 4, 4, and 16 microg/mL, respectively. 相似文献