全文获取类型
收费全文 | 28597篇 |
免费 | 1808篇 |
国内免费 | 381篇 |
专业分类
耳鼻咽喉 | 574篇 |
儿科学 | 322篇 |
妇产科学 | 461篇 |
基础医学 | 4656篇 |
口腔科学 | 431篇 |
临床医学 | 2396篇 |
内科学 | 5593篇 |
皮肤病学 | 1183篇 |
神经病学 | 2106篇 |
特种医学 | 2183篇 |
外科学 | 3752篇 |
综合类 | 162篇 |
一般理论 | 20篇 |
预防医学 | 832篇 |
眼科学 | 646篇 |
药学 | 2719篇 |
中国医学 | 403篇 |
肿瘤学 | 2347篇 |
出版年
2024年 | 18篇 |
2023年 | 246篇 |
2022年 | 768篇 |
2021年 | 1174篇 |
2020年 | 572篇 |
2019年 | 826篇 |
2018年 | 984篇 |
2017年 | 810篇 |
2016年 | 1218篇 |
2015年 | 1679篇 |
2014年 | 1879篇 |
2013年 | 2028篇 |
2012年 | 2951篇 |
2011年 | 2758篇 |
2010年 | 1781篇 |
2009年 | 1371篇 |
2008年 | 1735篇 |
2007年 | 1618篇 |
2006年 | 1467篇 |
2005年 | 1300篇 |
2004年 | 971篇 |
2003年 | 838篇 |
2002年 | 707篇 |
2001年 | 165篇 |
2000年 | 126篇 |
1999年 | 107篇 |
1998年 | 92篇 |
1997年 | 76篇 |
1996年 | 56篇 |
1995年 | 44篇 |
1994年 | 46篇 |
1993年 | 37篇 |
1992年 | 31篇 |
1991年 | 46篇 |
1990年 | 23篇 |
1989年 | 19篇 |
1988年 | 22篇 |
1987年 | 17篇 |
1986年 | 24篇 |
1985年 | 7篇 |
1984年 | 15篇 |
1983年 | 19篇 |
1982年 | 22篇 |
1981年 | 14篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1973年 | 6篇 |
1972年 | 12篇 |
1971年 | 10篇 |
1969年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The immunity of a combined DNA vaccine of HSV-2 glycoproteins B2 (gB2) and D2 (gD2) genes in comparison to individual vaccines was studied with regard to protecting against the HSV infection. Two recombinant DNA vaccines of the pHS2-gB2 or pHS2-gD2 were constructed and formulated. The neutralizing antibody titers appeared higher in the B2:D2 gene cocktail-vaccinated mice than that of the individual B2 or D2 gene-vaccinated group alone, and the positive KOS control induced higher titer of the neutralizing antibody than combined or individual gene vaccines. The mock-immunized mice failed to induce enough. The ranks for the CTL activity and the protection rates against the lethal intravaginal challenge were shown as KOS>B2:D2 cocktail>D2>B2 gene vaccines. The vaginal external diseases in the B2:D2 or D-vaccinated mice were significantly reduced against the challenging dosages. The virus titers in the vaginal secretions of the vaccinated mice significantly reduced with time, and the B2:D2 gene vaccine decreased more than each individual vaccine alone. It can be concluded that the cocktailed vaccines are more effective in the humoral and cellular immune responses in the mice, and in the protection of the mice against the intravaginal challenging dosages when compared with individual gene vaccines. All the DNA vaccines failed to block the latent infection in sensory nerves. 相似文献
52.
Kazuo Soga Takeshi Shiono Hyun Joon Kim 《Macromolecular chemistry and physics.》1993,194(12):3499-3504
A modified SiO2 was prepared by reacting SiO2 with Cl2Si(CH3)2 in toluene, on which methylaluminoxane (MAO) was supported to obtain a catalyst precursor. The mixture of the precursor and Cp2ZrCl2 (Cp: cyclopentadienyl) gave polyethylene in a high yield even by using common trialkylaluminiums as cocatalyst. Surprisingly, the MAO-free catalyst system composed of the modified SiO2 and Cp2ZrCl2 was also found to be activated by common trialkylaluminiums. 相似文献
53.
Summary: The latent thermal cationic initiators, benzyl‐2,5‐dimethylpyrazinium hexafluoroantimonate (BDPH) and benzyl‐2‐ethylpyrazinium hexafluoroantimonate (BEPH), were synthesized to investigate the effect of substituted alkyl groups on cure and dynamic mechanical behaviors of difunctional epoxy system. The cure temperature and activation energy of the diglycidyl ether of bisphenol A (DGEBA)/BDPH were higher than those of the DGEBA/BEPH, resulting from the steric hindrance of the substituted groups. The cross‐linking density of the DGEBA/BDPH was higher than that of the DGEBA/BEPH, whereas the Tg's of both specimens are similar. This may be explained by the free volume and the intermolecular hydrogen bonding induced by the hydrogen of the substituted methyl groups. Consequently, the position and number of the substituted groups of the latent thermal initiator were very important in the control of the latent thermal and dynamic mechanical behaviors of the epoxy resin.
54.
Loss of heterozygosity on chromosomes 3p,8p,9p and 17p in the progression of squamous cell carcinoma of the larynx 总被引:4,自引:0,他引:4
Yoo WJ Cho SH Lee YS Park GS Kim MS Kim BK Park WS Lee JY Kang CS 《Journal of Korean medical science》2004,19(3):345-351
Previous molecular genetic studies of laryngeal squamous cell carcinoma (SCC)have shown certain chromosomal regions with recurring alterations. But studies of sequential molecular alterations and genetic progression model of laryngeal SCC have not been clearly defined. To identify the chromosomal alterations associated with the carcinogenesis of laryngeal SCC, we analyzed genomic DNA from microdissected squamous metaplasia, squamous dysplasia, invasive SCC, and metastatic carcinoma samples from 22 laryngeal SCC patients for loss of heterozygosity (LOH) at microsatellite loci. Ten microsatellite markers on chromosome 3p, 8p, 9p, and 17p were used. LOH at 9p21 was observed in the all stages including squamous metaplasia, squamous dysplasia, invasive SCC and metastatic carcinoma. LOH at 17p13.1, 3p25 and 3p14.2 was observed from the squamous dysplasia, invasive SCC and metastatic carcinoma. LOH at 8p21.3-p22 was observed mainly from the invasive SCC and metastatic carcinoma. The results suggest that 9p21 in the early event, 17p13.1, 3p25 and 3p14.2 in the intermediate event and 8p21.3- p22 in the late event may be involved in the laryngeal carcinogenesis. 相似文献
55.
Methods for derivation of human embryonic stem cells 总被引:6,自引:0,他引:6
Kim HS Oh SK Park YB Ahn HJ Sung KC Kang MJ Lee LA Suh CS Kim SH Kim DW Moon SY 《Stem cells (Dayton, Ohio)》2005,23(9):1228-1233
The expanded blastocysts, developed from 2PN-stage embryos, are generally divided into three categories: a good blastocyst containing a large and distinguishable inner cell mass (ICM), a blastocyst with a small and distinct ICM, and a blastocyst with a poorly defined ICM. In this study, we introduce methods for the derivation of human embryonic stem cells (hESCs) depending on the quality of the blastocysts. An immunosurgical method was used for the good expanded blastocysts. This method, however, raises the probability of ICM loss in cases of hESC derivation from blastocysts with smaller or indistinct ICMs. Furthermore, this method is also associated with a risk of the contamination of the hESCs with animal pathogens. To overcome these shortcomings, the partial- or whole-embryo culture method was used. For blastocysts with no visible ICM, the whole-embryo culture method was used to establish hESCs via the seeding of the entire blastocyst without its zona pellucida directly on a STO feeder layer. However, trophectodermal overgrowth tends to hinder the expansion of the ICM during the initial steps of hESC derivation. Therefore, the partial-embryo culture method was developed to establish hESCs from blastocysts with smaller ICMs. The surgical isolation of the region containing the ICM with an ultra-fine glass pipette alleviates trophectoderm overgrowth. This method is also applicable to blastocysts with large and distinct ICMs, and the efficiency of this method is comparable to that of the immunosurgical method. 相似文献
56.
Successful treatment of refractory thrombocytopenia with mycophenolate mofetil in a patient with systemic lupus erythematosus 总被引:1,自引:0,他引:1
Chang HK 《Journal of Korean medical science》2005,20(5):883-885
While mild thrombocytopenia in systemic lupus erythematosus (SLE) is frequently seen in the context of active disease, severe thrombocytopenia causing significant bleeding is not that common. Corticosteroids are considered the first line therapy for severe thrombocytopenia in SLE. Second-line therapeutic agents or splenectomy have been reported to be effective for patients who fail to respond to steroids or those who require moderate doses of steroids to maintain the platelet counts. Recent randomized controlled studies have shown that mycophenolate mofetil (MMF) is an efficacious and safe therapeutic agent in patients with proliferative forms of lupus nephritis. However, little information has been available regarding the role of MMF in the treatment of immune thrombocytopenia complicated with SLE. Hereby I describe a patient with SLE in whom thrombocytopenia was refractory to corticosteroids, intermittent intravenous cyclophosphamide, azathioprine, cyclosporine, intravenous gamma globulin, danazol, and splenectomy, and whose platelet counts eventually normalized during therapy with MMF. In this patient, thrombocytopenia is initially thought to be associated with active SLE involving major organ. However, after immunosuppressive agents were given, the refractory nature of thrombocytopenia seems to be an isolated phenomenon, independently of SLE activity. 相似文献
57.
Kim HK Choi YH Ryu SM Kim HK Chae YS Sohn YS Kim HJ 《Journal of Korean medical science》2005,20(6):1070-1072
Infradiaphragmatic extralobar pulmonary sequestration is an extremely rare congenital malformation. It is more frequently diagnosed in the antenatal period due to routine ultrasonic examination of the fetus or in the first 6 months of life, though on rare occasions it is discovered incidentally in adults. A 32-yr-old man presenting with epigastric discomfort and fever was referred. Computed tomographic scanning showed that a 16-cm, multiseptated, dumbbell-shaped, huge cystic tumor was located beneath the diaphragm. On the next day, 850 mL of thick yellowish pus was drained by sonography-guided fine needle aspiration for the purpose of infection control and diagnosis, but no microscopic organisms were found in repeated culture studies. Surgical removal of the cyst was performed through thoracoabdominal incision and most of these pathologic lesions were removed but we could not find the feeding arteries or any fistulous tract to surrounding structures. Histopathologic study revealed that it was extralobar pulmonary sequestration and culture study showed that many WBC and necrotic materials were found but there were no microorganisms in the cystic contents. We report the first case of an infected infradiaphragmatic retroperitoneal extralobar sequestration which was administered a staged management and achieved an excellent clinical course. 相似文献
58.
Kim MS Seo KS Seong HS Cho SH Lee HB Hong KD Kim SK Khang G 《Bio-medical materials and engineering》2005,15(3):229-238
p-Carboxyphenoxy propane (CPP) prepolymer consisting of 4 units and sebacic acid (SA) prepolymer consisting of about 10 units were synthesized by reacting CPP and SA in the presence of excess acetic anhydride, respectively. Polyanhydride, poly(CPP-SA) copolymers were copolymerized by a melt polycondensation process with a mixture of CPP and SA prepolymer. Copolymers of average molecular weight up to 110,000 g/mol were achieved. The crystallinity of poly(CPP-SA) copolymers was decreased by the addition of the CPP homopolymer segment to SA homopolymer. Poly(CPP-SA) copolymers gradually degraded for period of 10 days. No large difference of weight loss observed according to molecular weight variation of poly(CPP-SA) copolymers. BCNU release from wafers fabricated by poly(CPP-SA) showed a sustained release pattern with no initial burst and delay of drug release. 相似文献
59.
The predominant enzymes responsible for elimination of hydrogen peroxide (H(2)O(2)) in cells are peroxiredoxins (Prxs), catalase, and glutathione peroxidases (GPxs). Evidence suggests that catalytic activities of certain isoforms of these H(2)O(2)-eliminating enzymes are extensively regulated via posttranslational modification. Prx I and Prx II become inactivated when phosphorylated on Thr(90) by cyclin B-dependent kinase Cdc2. In addition, the active-site cysteine of Prx I-IV undergoes a reversible sulfinylation (oxidation to cysteine sulfinic acid) in cells. Desulfinylation (reduction to cysteine) is achieved by a novel enzyme named sulfiredoxin. c-Abl and Arg nonreceptor protein tyrosine kinases associate with catalase in cells treated with H(2)O(2) by mechanisms involving the SH3 domains of the kinases and the Pro(293)PheAsnPro motif of catalase and activate catalase by phosphorylating it on Tyr(231) and Tyr(386). Similarily, GPx1 is activated by c-Abl- and Arg-mediated phosphorylation. The tyrosine phosphorylation is critical for ubiquitination-dependent degradation of catalase. 相似文献
60.
This study was performed to investigate the effects of behavior modification on body image, depression and body fat in obese elementary school children. Sixty-two elementary students of the 4th to 6th grade were selected from two different Seoul schools. Thirty-four children in one school were designated as the experimental group, and 28 children from the other school as the control group. The experimental group received 60 - 70 minutes of behavior modification, once a week, for 8 weeks. The control group received neither management nor treatment. The results indicated a significant improvement of body image and a reduction in the increase rate of body fat for the experimental group. This finding strongly supports the theory that behavior modification can be used as an effective strategy in the treatment of obese children. 相似文献