全文获取类型
收费全文 | 2829篇 |
免费 | 149篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 250篇 |
妇产科学 | 54篇 |
基础医学 | 363篇 |
口腔科学 | 69篇 |
临床医学 | 310篇 |
内科学 | 618篇 |
皮肤病学 | 83篇 |
神经病学 | 135篇 |
特种医学 | 411篇 |
外国民族医学 | 2篇 |
外科学 | 205篇 |
综合类 | 57篇 |
预防医学 | 154篇 |
眼科学 | 26篇 |
药学 | 151篇 |
2篇 | |
中国医学 | 1篇 |
肿瘤学 | 152篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 23篇 |
2020年 | 17篇 |
2019年 | 29篇 |
2018年 | 40篇 |
2017年 | 35篇 |
2016年 | 37篇 |
2015年 | 49篇 |
2014年 | 63篇 |
2013年 | 86篇 |
2012年 | 67篇 |
2011年 | 76篇 |
2010年 | 111篇 |
2009年 | 97篇 |
2008年 | 83篇 |
2007年 | 128篇 |
2006年 | 90篇 |
2005年 | 98篇 |
2004年 | 78篇 |
2003年 | 46篇 |
2002年 | 66篇 |
2001年 | 90篇 |
2000年 | 70篇 |
1999年 | 56篇 |
1998年 | 135篇 |
1997年 | 163篇 |
1996年 | 139篇 |
1995年 | 114篇 |
1994年 | 120篇 |
1993年 | 104篇 |
1992年 | 38篇 |
1991年 | 45篇 |
1990年 | 42篇 |
1989年 | 76篇 |
1988年 | 59篇 |
1987年 | 56篇 |
1986年 | 60篇 |
1985年 | 53篇 |
1984年 | 39篇 |
1983年 | 23篇 |
1982年 | 27篇 |
1981年 | 35篇 |
1980年 | 28篇 |
1979年 | 6篇 |
1978年 | 12篇 |
1977年 | 21篇 |
1976年 | 33篇 |
1975年 | 20篇 |
1970年 | 7篇 |
排序方式: 共有3053条查询结果,搜索用时 139 毫秒
861.
Sander?M?Slootmaker Marijke?JM?Chin A PawEmail author Albertine?J?Schuit Jacob?C?Seidell Willem?van Mechelen 《BMC public health》2005,5(1):134
Background
Ageing is associated with a decrease in physical activity. This decrease particularly occurs during specific transitional life stages. Especially during adolescence and young adulthood a steep decrease in physical activity is observed. Inactive people are often not aware of their inactivity. Providing feedback on the actual physical activity level by an activity monitor can increase awareness and may in combination with an individually tailored physical activity advice stimulate a physically active lifestyle. 相似文献862.
Agesen TH Flørenes VA Molenaar WM Lind GE Berner JM Plaat BE Komdeur R Myklebost O van den Berg E Lothe RA 《Journal of neuropathology and experimental neurology》2005,64(1):74-81
The molecular biology underlying the development of highly malignant peripheral nerve sheath tumors (MPNSTs) remains mostly unknown. In the present study, the expression pattern of 10 selected cell cycle components is investigated in a series of 15 MPNSTs from patients with (n = 9) or without (n = 5) neurofibromatosis type 1 (NF1). Thirteen tumors did not express the cyclin-dependent kinase inhibitor, p16(INK4A), an observation that was related to homozygote gene deletions in three tumors, heterozygote deletions in five, and gross gene rearrangements in five. The absence of protein expression in the tumors with one seemingly intact allele was not caused by promoter hypermethylation of p16(INK4A) or p14(ARF). All tumor samples expressed normal sized RB1, cyclin D3, CDK2, CDK4, p21(CIP1), and p27(KlP1) proteins, and only a single tumor showed an aberrant protein band for one of these proteins, p21(CIP1). Cyclin D1 was absent in four tumors; all except one tumor showed expression of TP53 protein, and three of nine MPNSTs had expression of normal-sized MDM2. In conclusion, this study shows that the vast majority of MPNSTs had gross rearrangements of the p16(INK4A) gene, explaining the absence of the encoded protein in the same tumors. The level of expression was equally distributed between the familial (NF1) and sporadic cases, although it should be noted that the 2 cases with p16(INK4A) expression were sporadic. The data imply that the complete absence of p16(INK4A) is sufficient for activation of the cell cycle in most MPNSTs; thus, it is not necessary for tumor proliferation to further stimulate the cycle through alteration of other central components. 相似文献
863.
Heterogeneity of genotype-phenotype correlation among macrolide-resistant Streptococcus agalactiae isolates 下载免费PDF全文
von Both U Buerckstuemmer A Fluegge K Berner R 《Antimicrobial agents and chemotherapy》2005,49(7):3080-3082
Seventy-four erythromycin-resistant group B Streptococcus isolates were analyzed regarding their phenotype-genotype and phenotype-serotype correlation. Four different phenotypes were assessed, one of them for the first time. ermB and ermTR were the most frequent genotypes (80%). The most prevalent serotype III showed great phenotypic variability while serotype V was strongly associated only with two different phenotypes. 相似文献
864.
865.
866.
Marci E Schaner Ben Davidson Martina Skrede Reuven Reich Vivi Ann Fl?renes Bj?rn Risberg Aasmund Berner Iris Goldberg Vered Givant-Horwitz Claes G Tropè Gunnar B Kristensen Jahn M Nesland Anne-Lise B?rresen-Dale 《Molecular cancer》2005,4(1):1-14
Background
While numerous studies have characterized primary ovarian tumors, little information is available regarding expression patterns of metastatic sites of this cancer. To define sets of genes that distinguish primary and metastatic ovarian tumors, we used cDNA microarrays to characterize global gene expression patterns in 38 effusions (28 peritoneal, 10 pleural) and 8 corresponding primary ovarian tumors, and searched for associations between expression patterns and clinical parameters.Results
We observed multidimensional variation in expression patterns among the cancers. Coordinate variation in expression of genes from two chromosomal regions, 8q and 19q, was seen in subsets of the cancers indicating possible amplifications in these regions. A set of 112 unique genes of known function was differentially expressed between primary tumors and effusions using supervised analysis. Relatively few differences were seen between effusions isolated from the pleural and peritoneal cavities or between effusions from patients diagnosed with stage III and stage IV cancers. A set of 84 unique genes was identified that distinguished high from lower grade ovarian cancers. The results were corroborated using immunocytochemistry, mRNA in situ hybridization, and immunoblotting.Conclusion
The extensive variation in expression patterns observed underscores the molecular heterogeneity of ovarian cancer, but suggests a similar molecular profile for ovarian carcinoma cells in serosal cavities. 相似文献867.
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominantly inherited disorder, characterised by the occurrence of tumours of the parathyroid glands, the pancreatic islets, the pituitary gland, the adrenal glands and neuroendocrine carcinoid tumours. Carcinoid tumours of the thymus and pancreatic-duodenal gastrinomas are the most harmful tumour types, since these tumours have malignant potential and curative treatment is difficult to achieve.MEN1 is caused by germline mutations of the MEN1 tumour suppressor gene. Mutation analysis enables mutation carriers to be identified. MEN1 patients and their family members, family members of mutation carriers and patients who are clinically suspected to be carriers of a MEN1 gene mutation are eligible for mutation analysis. MEN1-associated tumours can be detected and treated at an early stage through periodical clinical monitoring of mutation carriers. 相似文献
868.
Lessons from genetic profiling in soft tissue sarcomas 总被引:3,自引:0,他引:3
Nilbert M Meza-Zepeda LA Francis P Berner JM Namløs HM Fernebro J Myklebost O 《Acta orthopaedica Scandinavica. Supplementum》2004,75(311):35-50
Soft tissue sarcomas represent a heterogeneous group of tumors and include over 50 histotypes. Some of these tumor types are characterized by specific chromosomal translocations, whereas other types show complex genetic aberrations. The recent developments within gene expression technologies have now been applied to studies of soft tissue sarcomas (STS) and the first results indicate that genetic signatures are useful for classification and diagnosis. Distinctive expression profiles have been found in e.g. gastrointestinal stromal tumors (GISTs), synovial sarcomas, malignant peripheral nerve sheath tumors (MPNSTs), and in subsets of liposarcomas. The more pleomorphic tumor types, such as high-grade variants of leiomyosarcomas, malignant fibrous histiocytomas (MFHs), fibrosarcomas, and subtypes of liposarcomas, show a greater variability among the expression profiles, but interestingly subsets with distinctive expression profiles can be identified also among these tumors. The data available place many of the genes hypothesized to be involved in the development of a certain type of STS, such as the KIT gene in GIST development, among the top discriminating genes. Thereby expression profiling provides novel insights into the pathogenesis of STS. Although much work remains to be done to validate the data and to define optimal discriminating gene lists, the current lessons from gene expression studies in STS are encouraging and imply that genetic signatures may serve as diagnostic and prognostic markers and may help identify novel therapeutic strategies. 相似文献
869.
Adiponectin and its receptors are expressed in bone-forming cells 总被引:20,自引:0,他引:20
Berner HS Lyngstadaas SP Spahr A Monjo M Thommesen L Drevon CA Syversen U Reseland JE 《BONE》2004,35(4):842-849
870.
The treatment of splenic cysts is a difficult challenge to surgeons and physicians. This paper reviews the literature on splenic cysts, with special attention to the pathogenesis, diagnosis, and various options of surgical treatment. Splenic cysts are classified as primary or secondary cysts, according to the presence of an epithelial lining. The primary cysts are further subdivided as parasitic or non-parasitic. Secondary cysts are in most cases posttraumatic. Symptoms are usually correlated to the size of the cyst. Prior to surgery, imaging with ultrasound and computer tomography or magnetic resonance should be performed. A cyst puncture should be conducted for diagnostic purposes (amylase and bacteria) as well as to reduce the size of the cyst. Furthermore, the titer of Echinococcus and other biomarkers can be measured. Surgeons should make every possible effort to preserve splenic tissue and spleen-saving techniques with laparoscopic techniques are recommended. 相似文献