首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7411篇
  免费   395篇
  国内免费   82篇
耳鼻咽喉   86篇
儿科学   66篇
妇产科学   128篇
基础医学   1185篇
口腔科学   180篇
临床医学   494篇
内科学   1347篇
皮肤病学   214篇
神经病学   483篇
特种医学   513篇
外科学   919篇
综合类   34篇
预防医学   244篇
眼科学   99篇
药学   969篇
中国医学   161篇
肿瘤学   766篇
  2024年   4篇
  2023年   48篇
  2022年   169篇
  2021年   280篇
  2020年   123篇
  2019年   148篇
  2018年   229篇
  2017年   155篇
  2016年   271篇
  2015年   417篇
  2014年   416篇
  2013年   488篇
  2012年   813篇
  2011年   712篇
  2010年   416篇
  2009年   339篇
  2008年   445篇
  2007年   355篇
  2006年   342篇
  2005年   367篇
  2004年   308篇
  2003年   229篇
  2002年   181篇
  2001年   107篇
  2000年   104篇
  1999年   70篇
  1998年   33篇
  1997年   39篇
  1996年   30篇
  1995年   18篇
  1994年   22篇
  1993年   11篇
  1992年   15篇
  1991年   25篇
  1990年   14篇
  1989年   13篇
  1988年   18篇
  1987年   23篇
  1986年   16篇
  1985年   13篇
  1984年   8篇
  1983年   3篇
  1982年   5篇
  1981年   9篇
  1980年   5篇
  1979年   4篇
  1978年   5篇
  1977年   4篇
  1976年   7篇
  1975年   5篇
排序方式: 共有7888条查询结果,搜索用时 15 毫秒
991.
Visible Korean Human: its techniques and applications   总被引:4,自引:0,他引:4  
Three recent studies have offered an unprecedented view of the human body. The Visible Human Project, the Visible Korean Human (VKH), and the Chinese Visible Human have featured the serial sectioning of whole cadavers, producing cross-sectional images that methodically catalogue gross human anatomy. By volumetric reconstruction, these cross-sectional images can be transformed into three-dimensional (3D) images of anatomic structures. Compiling these 3D images would create an invaluable library for medical education and research. The goal of this report is to promote the expansion of such a library of 3D anatomic images and to help users fully understand and utilize the serially sectioned images. To do this, we will discuss the fundamental techniques and equipment used in the VKH and its preliminary experiments. We will also address new applications of the VKH, including virtual brain surgery, virtual endoscopy, and virtual cardiopulmonary resuscitation via the development of virtual dissection software.  相似文献   
992.
Coexpression of Kit ligand and c-kit has been reported in some gynecologic tumors. To determine whether imatinib mesylate is useful in ovarian epithelial tumors, we performed immunohistochemical and mutational analysis. The cases consisted of 33 cases, which included 13 serous cystadenocarcinomas, 1 borderline serous tumor, 8 mucinous cystadenocarcinomas, 6 borderline mucinous tumors and 5 clear cell carcinomas. Five cases of serous cystadenoma and 5 cases of mucinous cystadenoma were also included. In the immunohistochemical study, 3 cases (3/6, 50%) of borderline mucinous cystic tumor and two cases (2/8, 25%) of mucinous cystadenocarcinoma show positive staining for KIT protein. Only one case (1/13, 7.7%) of serous cystadenocarcinoma had positive staining. On mutational analysis, no mutation was identified at exon 11. However, two cases of borderline mucinous tumors and one case of mucinous cystadenocarcinoma had mutations at exon 17. In these cases, the immunohistochemistry also shows focal positive staining at epithelial component. Although, KIT protein expression showed higher incidence in mucinous tumors than serous tumors, they lack KIT-activating mutations in exon 11. Thus, ovarian surface epithelial tumors are unlikely to respond to imatinib mesylate.  相似文献   
993.
Heart rate (HR) recovery after exercise is a function of vagal reactivation, and its impairment is a predictor of overall mortality and adverse cardiovascular events. While metabolic syndrome is associated with sympathetic overactivity, little is known about the relationship between metabolic syndrome and HR recovery. A symptom-limited exercise stress test in healthy subjects (n=1, 434) was used to evaluate HR recovery. Metabolic syndrome was defined according to the National Cholesterol Education Program's Adult Treatment Panel III (NCEP ATP-III) criteria. Seventeen percent of subjects had > or =3 criteria for metabolic syndrome. HR recovery was lower in men than women and in smokers than nonsmokers. The subject with metabolic syndrome (vs. without) showed lower HR recovery (10.3+/-11.6 vs. 13.6+/-9.7 per minute) and higher resting HR (64.3+/-10.3 vs. 61.6+/-9.1 per minute). HR recovery correlated inversely to age (r=-0.25, p<0.0001), but not to resting HR or maximal oxygen uptake. Delayed HR recovery was associated with metabolic syndrome after an adjustment for age, sex, resting HR and smoking (p<0.01). Metabolic syn-drome is associated with impaired vagal reactivation. Adverse cardiovascular out-comes associated with metabolic syndrome may be mediated by the failure of vagal reactivation in addition to sympathetic overactivity.  相似文献   
994.
Human cathepsin K, a cysteine proteinase of the papain family, has been recognized as a potential drug target for the treatment of osteoporosis. The predominant expression of cathepsin K in osteoclasts has rendered the enzyme into a major target for the development of novel antiresorptive drugs. Now, we report the pharmacological properties of OST-4077 [furan-2-carboxylic acid (1-{1-[4-fluoro-2-(2-oxo-pyrrolidin-1-yl)-phenyl]-3-oxo-piperidin-4-ylcarbamoyl}-cyclohexyl)-amide] as a novel selective cathepsin K inhibitor. Human and rat cathepsin K were inhibited in vitro by OST-4077 with the IC50 values of 11 and 427 nM, respectively. OST-4077 suppressed bone resorption induced by rabbit osteoclasts (IC50, 37 nM) but did not affect bone mineralization or cellular alkaline phosphatase activity in MC3T3-E1 cells. Parathyroid hormone-induced bone resorption was inhibited in a dose-dependent manner in thyroparathyroidectomized rats gavaged with a single dose of OST-4077 (ED50, 69 mg/kg). When given orally twice daily for 4 weeks to 3-month-old ovariectomized (OVX) rats, OST-4077 dose-dependently prevented bone loss, as monitored by bone densitometry, ash content, and urinary excretion of deoxypyridinoline. No change in serum osteocalcin in the OVX rats by OST-4077 suggested that bone formation might not be affected by the agent. In summary, OST-4077 selectively inhibited bone resorbing activities of osteoclasts and prevented bone loss induced by estrogen deficiency but did not affect bone formation. OST-4077, an orally active selective human cathepsin K inhibitor, may have the therapeutic potential for the treatment of diseases characterized by excessive bone loss including osteoporosis.  相似文献   
995.
Aspirin-intolerant asthma (AIA) is a distinct clinical syndrome that refers to the development of bronchoconstriction in asthmatic individuals following the ingestion of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs). It is widely recognized that increased cysteinyl leukotriene (cysLT) biosynthesis is associated with the development and progression of AIA. Leukotriene C4 synthase (LTC4S) is the terminal enzyme in cysLT production and is a strong candidate gene in the pathogenesis of aspirin-intolerant asthma (AIA). In this paper, we report a new single nucleotide polymorphism (SNP) of the LTC4S promoter, -1702G>A, in AIA patients and evaluate its genetic role in the association with the LTC4S-444 A>C polymorphism. We enrolled 110 AIA patients, 125 aspirin-tolerant asthma (ATA) patients, and 125 normal controls. SNP genotyping of the LTC4S-1702G>A and -444A>C polymorphisms was performed using SNP-IT assays. Haplotype analyses were performed using Haploview version 2.05, which is based on an estimation-maximization (EM) algorithm. There were no significant differences in the allele or genotype frequencies of the LTC4S-1702G>A and -444A>C polymorphisms among the three groups (p > 0.05), with no significant differences in the observed haplotype frequencies (p > 0.05). Moreover, no significant associations were found between the genotype of each SNP in AIA patients with the clinical characteristics, including a forced expiratory volume in one second (FEV1) %, a provocation concentration of methacholine to induce more than 20% decrease of FEV1 (PC20) to methacholine, and serum total IgE levels (p > 0.05). These results indicate that there is no association between these two promoter polymorphisms of LTC4S and the phenotype of AIA in a Korean population.  相似文献   
996.
997.
998.
OBJECTIVE: Anticitrullinating autoantibodies are specific markers for rheumatoid arthritis (RA). A functional haplotype of 4 exonic single-nucleotide polymorphisms (SNPs) in a citrullinating enzyme, peptidylarginine deiminase 4 (PADI4), was shown to be associated with susceptibility to RA in a Japanese population and was shown to increase the stability of PADI4 messenger RNA. However, the association was not confirmed in 4 subsequent studies involving Caucasian RA patients living in the UK, a French Caucasian population, and a Spanish population. The aim of the current study was to investigate the association of SNPs in the PADI4 gene with RA in a Korean population. METHODS: Four exonic SNPs of the PADI4 gene (padi4_89, padi4_90, padi4_92, and padi4_104) were genotyped in 545 unrelated patients with RA and 392 controls, using the MassArray SNP genotyping system. Allelic, genotypic, and haplotypic associations of the SNPs with RA susceptibility were examined using the chi-square test and multivariate logistic regression analyses. RESULTS: Increased RA susceptibility was significantly associated with the minor alleles of padi4_89 (P = 2.3 x 10(-5)), padi4_90 (P = 2.3 x 10(-5)), padi4_92 (P = 2.1 x 10(-5)), and padi4_104 (P = 1.1 x 10(-3)) and the haplotype carrying the 4 minor alleles (P = 1.0 x 10(-4)). Genotypes carrying the minor alleles and HLA-DRB1 shared epitope (SE) alleles (P = 9.4 x 10(-21)) were also associated with increased RA susceptibility. The genotypic associations were sustained among individuals who did not carry any SE alleles, except in the case of padi4_104. Individuals carrying the risk SNPs and/or SE alleles were more susceptible to RA than were individuals carrying neither risk SNPs nor SE alleles. CONCLUSION: The PADI4 SNPs and haplotypes are associated with RA susceptibility in Koreans. Thus, the association of PADI4 with RA may depend on genetic heterogeneity between Asians and Europeans.  相似文献   
999.
OBJECTIVE: In Japanese individuals, the -169C/T single-nucleotide polymorphism (SNP) in FCRL3 has been reported to be associated with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and autoimmune thyroid diseases. The objective of this study was to test the association of this SNP with RA and SLE, in a case-control study of Korean individuals. METHODS: The -169C/T SNP in FCRL3 was genotyped in 1,060 patients with RA, 457 patients with SLE, and 697 unaffected control subjects, using the MassARRAY SNP genotyping system. Associations were tested by multivariate logistic regression, with adjustments for age and sex. RESULTS: No association was detected between the -169C/T SNP and RA (odds ratio [OR] 1.11, 95% confidence interval [95% CI] 0.83-1.48, P = 0.50) or SLE (OR 1.00, 95% CI 0.73-1.37, P = 0.99). This SNP was not associated with rheumatoid factor status, shared epitope status, radiographic severity in patients with RA, or disease manifestations in patients with SLE. CONCLUSION: The association of the -169C/T SNP in FCRL3 with RA and SLE that was observed in Japanese patients was not replicated in a Korean population.  相似文献   
1000.
Vaccine assembly from surface proteins of Staphylococcus aureus   总被引:1,自引:0,他引:1       下载免费PDF全文
Staphylococcus aureus is the most common cause of hospital-acquired infection. Because of the emergence of antibiotic-resistant strains, these infections represent a serious public health threat. To develop a broadly protective vaccine, we tested cell wall-anchored surface proteins of S. aureus as antigens in a murine model of abscess formation. Immunization with four antigens (IsdA, IsdB, SdrD, and SdrE) generated significant protective immunity that correlated with the induction of opsonophagocytic antibodies. When assembled into a combined vaccine, the four surface proteins afforded high levels of protection against invasive disease or lethal challenge with human clinical S. aureus isolates.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号