全文获取类型
收费全文 | 45130篇 |
免费 | 2109篇 |
国内免费 | 371篇 |
专业分类
耳鼻咽喉 | 468篇 |
儿科学 | 816篇 |
妇产科学 | 1301篇 |
基础医学 | 5342篇 |
口腔科学 | 1711篇 |
临床医学 | 3468篇 |
内科学 | 12610篇 |
皮肤病学 | 953篇 |
神经病学 | 3933篇 |
特种医学 | 1187篇 |
外科学 | 6856篇 |
综合类 | 170篇 |
一般理论 | 9篇 |
预防医学 | 2459篇 |
眼科学 | 717篇 |
药学 | 2441篇 |
中国医学 | 114篇 |
肿瘤学 | 3055篇 |
出版年
2024年 | 40篇 |
2023年 | 322篇 |
2022年 | 777篇 |
2021年 | 1464篇 |
2020年 | 790篇 |
2019年 | 1124篇 |
2018年 | 1551篇 |
2017年 | 1019篇 |
2016年 | 1111篇 |
2015年 | 1306篇 |
2014年 | 1798篇 |
2013年 | 2356篇 |
2012年 | 3623篇 |
2011年 | 3575篇 |
2010年 | 2013篇 |
2009年 | 1751篇 |
2008年 | 3040篇 |
2007年 | 3159篇 |
2006年 | 2946篇 |
2005年 | 2915篇 |
2004年 | 2624篇 |
2003年 | 2351篇 |
2002年 | 2082篇 |
2001年 | 275篇 |
2000年 | 192篇 |
1999年 | 295篇 |
1998年 | 369篇 |
1997年 | 323篇 |
1996年 | 288篇 |
1995年 | 279篇 |
1994年 | 219篇 |
1993年 | 165篇 |
1992年 | 143篇 |
1991年 | 103篇 |
1990年 | 104篇 |
1989年 | 85篇 |
1988年 | 66篇 |
1987年 | 57篇 |
1986年 | 82篇 |
1985年 | 72篇 |
1984年 | 73篇 |
1983年 | 65篇 |
1982年 | 94篇 |
1981年 | 66篇 |
1980年 | 72篇 |
1979年 | 40篇 |
1978年 | 47篇 |
1977年 | 37篇 |
1976年 | 35篇 |
1974年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Montalto G Giannitrapani L Soresi M Virruso L Martino DD Gambino R Carroccio A Cervello M 《Inflammation》2001,25(2):101-108
E-selectin, an adhesion molecule of the selectin family, is involved in leukocyte adhesion to the endothelium and in the cellular immunological reactions. Expression of this molecule, in fact, is physiologically absent, but it becomes evident on sinusoidal lining cells during inflammatory liver disease. The aim of this study was to evaluate the behavior of E-selectin in chronic hepatitis C (CH-C) patients with persistently normal transaminase in comparison to patients with CH-C and elevated transaminase, and its changes during alpha-interferon therapy. Immunohistochemical localization of E-selectin was also performed on liver tissue specimens of both groups. Fifty-eight subjects were divided into 3 groups: group A included 18 patients with CH-C and persistently normal transaminase; group B 20 patients with CH-C and persistently elevated transaminase levels and group C included 20 healthy subjects, representing the control group. The first two groups were treated with r-IFN at a dose of 6 MU 3 times a week for 3 months and followed-up with 3 MU 3 times a week for another 3 months. Serum baseline values of E-selectin in groups A and B were significantly higher than those in group C (P < 0.04), but there was no difference between groups A and B. Furthermore, there was a trend toward higher E-selectin values as histological severity increased (r = 0.69; P < 0.0001). Post-treatment E-selectin serum values showed a moderate decrease in both groups, but only among responder patients; while E-selectin levels were unchanged in non responders. Immunohistochemical localization showed no staining for E-selectin in normal liver specimens, while there was a quite similar staining for E-selectin in the two groups of patients. In conclusion, this study shows that serum E-selectin levels in patients with CH-C and persistently normal transaminase are higher than in controls and they are associated with severity of liver disease. Liver of these patients express E-selectin molecules, suggesting an activation of the immune system almost identical to that of patients with CH-C and elevated transaminase. In both groups only responder patients showed a moderate decrease below baseline serum values. 相似文献
92.
93.
John David N. Dionisio Alfonso F. Cárdenas PhD Robert B. Lufkin Antonio DeSalles Keith L. Black Ricky K. Taira Wesley W. Chu 《Journal of digital imaging》1997,10(1):21-26
A prototype multimedia medical database is described for supporting thermal ablation therapy of brain tumors. Its design is motivated by the major need to manage and access multimedia information on the progress and reaction of tumors to various therapy protocols. The database links images to patient data in a way that permits the user to view and query medical information using alphanumeric, temporal, and feature-based predicates. Visualization programs permit the user to view or annotate the query results in various ways. These results support the wide variety of data types and presentation methods required by neuroradiologists to manage thermal ablation therapy data. The database satisfactorily meets the requirements defined by thermal ablation therapy. A similar approach is being undertaken for supporting different therapies of other types of tumors, thus showing the generality of our approach. 相似文献
94.
The yeast Phaffia rhodozyma, a promising microbial producer of the carotenoid astaxanthin, was cultivated in batch and continuous processes in an agitated and aerated fermenter using an acid peat extract - based culture medium. For the accelerated growth phase, the mean specific growth rate and doubling time were found to be 0.038 h?1, and 18.24 hours, respectively. The production of astaxanthin was found to be basically growth associated, the maximum concentrations of the pigment produced in batch culture and continuous cultivation being similar. 相似文献
95.
Accelerated solvent extraction and liquid chromatography-tandem mass spectrometry quantitation of corticosteroid residues in bovine liver 总被引:1,自引:0,他引:1
Draisci R Marchiafava C Palleschi L Cammarata P Cavalli S 《Journal of chromatography. B, Biomedical sciences and applications》2001,753(2):217-223
A new method for the rapid extraction and unequivocal confirmation of two highly potent fluorinated synthetic corticosteroids, dexamethasone and its beta-epimer betamethasone, in bovine liver was developed. Flumethasone was used as internal standard. An extraction procedure using an accelerated solvent extraction system was employed for the isolation of the analytes in liver samples. The procedure was highly automated, including defatting and extraction steps, sequentially carried out under 1.0 x 10(4) kPa in about 35 min. The extracts were then directly analysed by tandem mass spectrometry with on-line liquid chromatography. The analytes were ionised in a heated nebulizer interface operating in the negative ion mode where the molecular related ions [M-H-CH2O]- were generated for each analyte, at m/z 361 for betamethasone and dexamethasone and at m/z 379 for flumethasone. They served as precursor ions for collision-induced dissociation and three diagnostic product ions for the drugs were identified to carry out analyte confirmation by selected reaction monitoring. Assessment of recovery, specificity and precision for betamethasone, dexamethasone and flumethasone proved the method suitable for confirmatory purposes. The limit of quantification of betamethasone and dexamethasone in liver tissue was 1.0 microg/kg. 相似文献
96.
97.
Antonia D'Errico Walter F. Grigioni Michelangelo Fiorentino Paola Baccarinl Eugene Lamas Stella De Mitri Giuseppe Gozzetti Antonio M. Mancini Christian Brechot 《Pathology international》1994,44(2):131-137
Recent results obtained using molecular biology techniques have suggested a possible role for insulin-like growth factor II (IGF-II) in the pathogenesis of hepatocellular carcinoma (HCC). To investigate this phenomenon, a monoclonal anti-body was used against IGF-II to study 54 patients with HCC. The presence of HBsAg was also tested both in serum and liver tissue. A positive immunoreaction was found in 9/15 (60%) of the HCC arising in cirrhotic livers of patients who had serum markers for HBV (HBV+ positive patients). These results provide further evidence that HBV might play a role in the expression of IGF-II. In HCC of patients without any markers of HBV infection (HBV- negative patients), IGF–II was detected in 10/39 (25.6%) of the tumors, and in some benign neoplastic lesions. It was found not only in neoplastic cells but also in some dysplastic nodules. The speculation arises that IGF–II expression may play a role in some steps of hepato-carcinogenesis. 相似文献
98.
Urzì F Iannello A Torrisi A Foti P Mortellaro NF Cavallaro M 《Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia》2003,108(2):83-117
The pterion is one of the most interesting bone meeting points in craniofacial osteology and its complex morphology derives from the fact that is the contact point of the facial skeletal elements, skull base and calvarium. Knowledge of its peculiar morphology is mandatory for the pterional approach used in microsurgery and surgery. The Authors studied 506 adult, human skulls where the pterion was accurately reconstructed on polyethylene sheets. They report their data on the morphological analysis and classify the forms. They focussed their attention on the presence of wormian bones at the level of the sphenoparietal suture, on the peculiar existing morphology and reviewed the literature on these classifications. The Authors also evaluated the length of the sphenoparietal suture, the minimum gap between the frontal and temporal, the influence of pteric bones on pterion variability and any correlations between measurements and cranial indexes. 相似文献
99.
González N Sancho V Martín-Duce A Tornero-Esteban P Valverde I Malaisse WJ Villanueva-Peñacarrillo ML 《International journal of molecular medicine》2005,16(4):747-752
Changes in the activity of glycogen synthase a and related kinases (phosphatidylinositol-3-kinase, protein kinase B, p44/42 MAP kinases and p70s6 kinase) evoked by GLP-1 in human myocytes from normal subjects were recently implied in the effect of this hormone upon D-glucose transport and glycogen synthesis in the same cells. The major aims of the present study were i) to investigate the possible extension of this knowledge to myocytes obtained from type 2 diabetic patients, ii) to compare in these patients the response to GLP-1, insulin or the structurally related GLP-1 peptides, exendin (1-39)amide and exendin(9-39)amide, and iii) to explore possible differences in the responsiveness to these agents between normal and diabetic subjects. Apart from the much higher basal PI3K activity and impaired response to insulin of p44/42 MAP kinases in the diabetic patients, the changes in enzyme activity caused by either hormone or peptide, although not identical, were essentially comparable. Nevertheless, significant differences in glucose transport and metabolism parameters were observed in the diabetic patients vs. normal subjects: in the diabetic patients, basal 2-deoxy-glucose uptake and glycogen synthase a activity were lower, accompanied by a similar increasing effect of GLP-1 or insulin; yet, the basal value for glycogen synthesis was higher, coinciding with a lesser relative increment in response to GLP-1 or insulin. 相似文献
100.
Lasalvia A Bonetto C Malchiodi F Salvi G Parabiaghi A Tansella M Ruggeri M 《Psychological medicine》2005,35(11):1655-1665
BACKGROUND: Subjective quality of life has gained a crucial role as a global measure of outcome in mental health care. This study aimed to investigate the impact of meeting needs for care, as assessed by both patients and mental health professionals, to improve the subjective quality of life in a sample of patients receiving community-based psychiatric care. METHOD: The study was conducted using a 4-year prospective longitudinal design. A cohort of patients from the South-Verona Community-based Mental Health Service (CMHS) was assessed at baseline and follow-up using, among other social and clinical measures, the Camberwell Assessment of Need (both staff and patient versions) and the Lancashire Quality of Life Profile. Predictors of changes of subjective quality of life were explored using block-stratified multiple regression procedures. RESULTS: Improvement in patients' clinical conditions as well as the reduction in patient-rated unmet needs in the social domain predicted an increase in subjective quality of life over 4 years; changes in staff-rated needs did not show any association with changes in subjective quality of life. CONCLUSIONS: Meeting self-perceived social needs, beyond symptoms reduction, seems to be of particular importance for ensuring a better quality of life for people with mental disorders. If the main goal of mental health care is to improve the quality of life of users, a policy of actively addressing patient-rated needs should be implemented. 相似文献