全文获取类型
收费全文 | 12701篇 |
免费 | 1023篇 |
国内免费 | 354篇 |
专业分类
耳鼻咽喉 | 201篇 |
儿科学 | 637篇 |
妇产科学 | 272篇 |
基础医学 | 1270篇 |
口腔科学 | 428篇 |
临床医学 | 1031篇 |
内科学 | 1082篇 |
皮肤病学 | 202篇 |
神经病学 | 640篇 |
特种医学 | 932篇 |
外国民族医学 | 4篇 |
外科学 | 1928篇 |
综合类 | 1358篇 |
现状与发展 | 3篇 |
预防医学 | 287篇 |
眼科学 | 154篇 |
药学 | 571篇 |
11篇 | |
中国医学 | 104篇 |
肿瘤学 | 2963篇 |
出版年
2024年 | 33篇 |
2023年 | 212篇 |
2022年 | 414篇 |
2021年 | 507篇 |
2020年 | 464篇 |
2019年 | 393篇 |
2018年 | 374篇 |
2017年 | 384篇 |
2016年 | 469篇 |
2015年 | 489篇 |
2014年 | 828篇 |
2013年 | 887篇 |
2012年 | 697篇 |
2011年 | 665篇 |
2010年 | 557篇 |
2009年 | 523篇 |
2008年 | 602篇 |
2007年 | 560篇 |
2006年 | 528篇 |
2005年 | 466篇 |
2004年 | 389篇 |
2003年 | 293篇 |
2002年 | 254篇 |
2001年 | 231篇 |
2000年 | 205篇 |
1999年 | 181篇 |
1998年 | 219篇 |
1997年 | 184篇 |
1996年 | 188篇 |
1995年 | 167篇 |
1994年 | 186篇 |
1993年 | 123篇 |
1992年 | 123篇 |
1991年 | 138篇 |
1990年 | 117篇 |
1989年 | 98篇 |
1988年 | 101篇 |
1987年 | 76篇 |
1986年 | 86篇 |
1985年 | 104篇 |
1984年 | 90篇 |
1983年 | 52篇 |
1982年 | 74篇 |
1981年 | 84篇 |
1980年 | 69篇 |
1979年 | 60篇 |
1978年 | 45篇 |
1977年 | 40篇 |
1976年 | 29篇 |
1975年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Microvascular structural entropy: A novel approach to assess angiogenesis in pituitary tumors 总被引:2,自引:0,他引:2
Entropy, a measure of the degree of disorder in a system, has recently been used in different morphologic studies to quantify
regularity. Our aims were (a) to study the structural organization of the microvascular bed in prolactin (PRL)-producing adenomas
and carcinomas, the most vascularized of pituitary tumors, by assessing microvascular structural entropy (MSE), and (b) to
determine whether the degree of disorder of the capillary bed correlates with tumor cell proliferation as estimated by MIB-1
labeling, microvessel density (MVD), the most widely used method of quantifying blood vessel formation, and various clinicopathologic
parameters (gender, age, tumor size and invasiveness). The morphometric study demonstrated statistically significant differences
in MIB-1 labeling, MVD, and MSE between PRL-producing adenomas and carcinomas. Unlike MIB-1 labeling index (PRL-producing
adenomas 1.5±0.27; carcinomas 15.0±4.04) and MVD (PRL-producing adenomas 2.7±0.34; carcinomas 4.2±0.72), the MSE values were
significantly higher in adenomas (171.5±25.37) than in carcinomas (67.9±17.45). These results indicate that PRL-producing
carcinomas have a less chaotic distribution of vessels than benign adenomas. In contrast to a lack of correlation between,
microvessel density and other morphometric parameters, a strong negative correlation was found between MSE and MIB-1 labeling
index (r=0.511, p=0.003). It thus appears that regular, less chaotic microvascular geometry contributes to increased proliferative activity
in PRL cell tumors. Analysis of MSE may provide an independent parameter of tumor behavior, and contributes to a better understanding
of the role of microvasculature in pituitary tumor progression. 相似文献
82.
Terracciano LM Bernasconi B Ruck P Stallmach T Briner J Sauter G Moch H Vecchione R Pollice L Pettinato G Gürtl B Ratschek M De Krijger R Tornillo L Bruder E 《Human pathology》2003,34(9):864-871
Hepatoblastoma (HB) is the most common liver tumor in childhood and differs in its environmental risk factors and genetic background from hepatocellular carcinoma. HB is associated with inherited conditions such as familial adenomatous polyposis and Beckwith-Wiedemann syndrome, suggesting the importance of genetic abnormalities in the pathogenesis and progression of this disease. It has a very polymorphous morphology. A diverse range of cytogenetic alterations has been reported to date, the most frequent being trisomy 2 and trisomy 20. Thirty-five HB specimens from 31 patients (22 purely epithelial, 4 purely mesenchymal, 9 mixed) were examined by comparative genomic hybridization (CGH), a technique that enables us to screen the entire tumor genome for genetic losses and gains. Our aims were as follows: (1) to characterize chromosome abnormalities that appear in this tumor and (2) to identify possible differences between different histologic subtypes of HB. We found significant gains of genetic material, with very little difference in the number and type of alterations between the different histologic components of HB. The most frequent alterations were gains of Xp (15 cases, 43%) and Xq (21 cases, 60%). This finding was also confirmed by fluorescent in situ hybridization performed on nuclei extracted from 6 specimens. Other common alterations were 1p-, 2q+, 2q-, 4q-, and 4q+. We found no difference between different histologic subtypes, a finding that may be in agreement with the hypothesis of a common clonal origin for the different components. An hitherto-unreported high frequency of X chromosome gains may support the assumption that X-linked genes are involved in the development of this neoplasm. 相似文献
83.
Radcliffe Jerilynn; Bennett David; Kazak Anne E.; Foley Bernadette; Phillips Peter C. 《Journal of pediatric psychology》1996,21(4):529-539
Examined the adjustment of 6- to 18-year-old children and adolescents(n = 38) 2 to 5 years postdiagnosis of brain tumor with respectto standardized measures of anxiety and depression; self-perceptions;and adaptive living skills. Child, mother, and teacher reportdata were used. Maternal adjustment (anxiety and depression,parenting stress) was also assessed. Children and adolescentssurviving brain tumors reported themselves to be generally withinthe normal range. However, maternal ratings of social problemswere higher than normative scores and significantly lower thannorms on social problems, scholastic competence, and communicationskills. Teacher ratings on the Teacher Rating Form were allwithin normal limits. Maternal adjustment measures were withinthe normal range, although the Parent-Child Dysfunctional Interactionsubscale of the Parenting Stress Index was elevated. No differencesin scores were found between children in regular and specialeducation, or between children who had received radiation andthose who did not. This sample of survivors of pediatric braintumors and their mothers had relatively mild problems in adjustment,supporting a competency-based view of the adaptation of pediatricpatients and their families. 相似文献
84.
Maria M. Picken 《Ultrastructural pathology》2005,29(3):277-282
The classification of renal tumors has evolved from one that initially encompassed only 2 types of tumors, i.e., clear and granular cell carcinomas, to the markedly expanded recent classification that incorporates new entities, some of which are primarily defined by specific molecular abnormalities. Despite these advances, a single tumor category, clear cell carcinoma, still incorporates the majority (∼70%) of renal tumors. It is, however, postulated that this single category is likely to encompass several different tumor types that are, at present, undifferentiated. Electron microscopic studies have been pivotal in defining the spectrum of oncocytoma-chromophobe renal cell carcinoma. Cytoplasmic eosinophilia found in some renal cell carcinomas currently classified as clear cell type is under intense study. Tumors that have recently emerged from this group include tumors with translocations involving chromosome Xp11.2, carcinomas associated with neuroblastoma and epithelioid angiomyolipoma. The spectrum of renal tumors seen in younger patients is wider than among older patients, with rare and unusual tumors being more likely seen in younger patients. The author concludes that although the routine application of electron microscopy to kidney tumor diagnosis may not be practical, systematic ultrastructural studies of these tumors may aid in the definition of new entities. 相似文献
85.
A case of papillary adenocarcinoma arising in Caroli's disease (CD) in a 25-yr-old woman is reported. The diagnosis of malignancy was made by ultrasound-guided, fine-needle aspiration biopsy (FNAB). As there were no metastasis, a liver transplant was performed and the diagnosis was histologically confirmed. Only 22 cases of malignant transformation of CD have been reported to date, all among middle-aged subjects (mean age: 52 yr) of both sexes. Most of these reported cases (83%) were found to be bile duct adenocarcinomas with occasional reports of hepatocellular and undifferentiated carcinomas. Our case is the youngest reported to date and the first to be diagnosed cytologically. 相似文献
86.
87.
Carlson-Green Bonnie; Morris Robin D.; Krawiecki Nicolas 《Journal of pediatric psychology》1995,20(6):769-784
Investigated the prediction of cognitive and behavioral outcomesin 63 children with heterogenous brain tumors. Hierarchicalmultiple regression analyses were used to determine how family-relatedvariables added to the prediction of children's outcome overand above illness measures. The best predictors of children'sbehavior problems and adaptive behavior were family and demographicvariables, whereas the best predictors of achievement were illnessand demographic variables. A combination of family and illnessvariables, however, was the best predictor of intellectual functioning.In addition to identifying specific predictors of cognitiveand behavioral outcome in children with brain tumors, theseresults lend initial support for the inclusion of contextualfactors such as family stress, maternal coping, number of parentsin the home, and family SES measures in studies of how diseasefactors affect outcomes in pediatric brain tumor patients. 相似文献
88.
Nafe R Gangnus R Glienke W Burgemeister R Haar B Pries A Schlote W 《Pathology, research and practice》2003,199(6):411-414
The technique of laser microdissection together with laser pressure catapulting (LMPC) is demonstrated in paraffin sections obtained from surgical specimens of brain tumors mounted on glass slides. A sufficient and precise application of microdissection techniques in tissue on glass slides is worthwhile, since it offers the possibility of a retrospective analysis of archived paraffin sections in histopathology. We could demonstrate a precise dissection of areas in tissues of different thicknesses (4 microm and 20 microm). Areas of tissue mounted directly on glass need to be dissected in a scanning mode in order to remove the total region in form of small tissue fragments row by row. This mode provided a precise microdissection of tissue areas of different sizes and shapes. A successful molecular biological analysis of the microdissected regions could be demonstrated. As an example for such an analysis, differential-PCR for detecting an amplification of the gene for the epidermal growth factor receptor (EGFR) was performed. 相似文献
89.
The histopathologic features of malignant peripheral nerve sheath tumors (MPNSTs) have been well described. There have been limited studies on the cytologic features of MPNST. In this present study, we have retrospectively reviewed eight histopathology confirmed cases of MPNST over a 5-year period. Detailed cytomorphological analysis of these cases was carried out individually by two observers. On cytology, these cases were diagnosed as benign spindle-cell tumor (two), spindle-cell tumor possibly benign (one), spindle-cell tumor possibly malignant (one), malignant spindle-cell tumor (two), spindle-cell tumor, and neural origin (two). The cardinal cytomorphologic features were loosely cohesive clusters and fascicular arrangement of spindle cells with rounded ends. The kinking of nuclei was not a conspicuous finding. Fibrillary background was noted in two of the cases. Nuclear pleomorphism was ranged from mild to moderate degree. One case exhibited extensive intranuclear pseudoinclusions. Mitotic figures (including atypical forms) were present in almost all the cases. Possibly a constellation of cytologic features such as clusters of short and long fascicles of cells admixed with dissociated spindle cells of round-ended nuclei and prominent nucleoli on myxoid or fibrillary background and frequent mitosis may be helpful in diagnosis of MPNSTs. The cytomorphologic features along with clinical correlation are necessary to increase the diagnostic accuracy of MPNST on aspiration cytology. 相似文献
90.
H.-G. Mergenthaler M. Fink H. Sauer R. Bartl W. Wilmanns 《Journal of molecular medicine (Berlin, Germany)》1989,67(1):42-46
Summary For years, brown tumors have been considered to be a characteristic of primary hyperparathyroidism. However, since 1963 several reports indicate the incidence of brown tumors in patients with renal secondary hyperparathyroidism to be 1.5%–1.7%. The appearance of multiple brown tumor lesions is rather uncommon in secondary hyperparathyroidism which is also true for malabsorption as its cause. We report on a 56-year-old man presenting with pain in the bones and multiple osteolyses. A bone biopsy specimen and the laboratory examinations were indicative of secondary hyperparathyroidism caused by malabsorption most likely due to Billroth's II/I gastric resection. Thus, the patient's osteolyses represent brown tumors which have been induced by nutritional secondary hyperparathyroidism. 相似文献