全文获取类型
收费全文 | 1038篇 |
免费 | 73篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 21篇 |
妇产科学 | 71篇 |
基础医学 | 105篇 |
口腔科学 | 10篇 |
临床医学 | 75篇 |
内科学 | 170篇 |
皮肤病学 | 5篇 |
神经病学 | 91篇 |
特种医学 | 79篇 |
外科学 | 57篇 |
综合类 | 5篇 |
预防医学 | 56篇 |
眼科学 | 3篇 |
药学 | 157篇 |
肿瘤学 | 211篇 |
出版年
2021年 | 10篇 |
2020年 | 15篇 |
2019年 | 10篇 |
2018年 | 17篇 |
2017年 | 12篇 |
2016年 | 14篇 |
2015年 | 16篇 |
2014年 | 24篇 |
2013年 | 18篇 |
2012年 | 35篇 |
2011年 | 41篇 |
2010年 | 26篇 |
2009年 | 28篇 |
2008年 | 29篇 |
2007年 | 54篇 |
2006年 | 38篇 |
2005年 | 34篇 |
2004年 | 38篇 |
2003年 | 37篇 |
2002年 | 31篇 |
2001年 | 51篇 |
2000年 | 34篇 |
1999年 | 31篇 |
1998年 | 19篇 |
1997年 | 18篇 |
1996年 | 18篇 |
1995年 | 18篇 |
1994年 | 19篇 |
1993年 | 16篇 |
1992年 | 32篇 |
1991年 | 34篇 |
1990年 | 40篇 |
1989年 | 43篇 |
1988年 | 30篇 |
1987年 | 26篇 |
1986年 | 30篇 |
1985年 | 24篇 |
1984年 | 22篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 14篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1966年 | 3篇 |
排序方式: 共有1129条查询结果,搜索用时 10 毫秒
51.
Immobilization device for in vivo and in vitro multimodality image registration of rodent tumors. 总被引:1,自引:0,他引:1
Nicolas Christian John A Lee Anne Bol Marc De Bast Bernard Gallez Vincent Grégoire 《Radiotherapy and oncology》2008,87(1):147-151
Biological image-guided radiotherapy requires that PET accurately identifies biologically relevant sub-volumes within a tumor. In this framework, an immobilization device was developed to study multi-imaging (CT, micro-MRI, micro-PET, and autoradiography) registration of mouse tumors. The registration accuracy assessed by calculating the average minimal distance between two skew lines was in the order of 0.2-0.3 mm. 相似文献
52.
A Berchuck G C Rodriguez A Kamel R K Dodge J T Soper D L Clarke-Pearson R C Bast 《American journal of obstetrics and gynecology》1991,164(2):669-674
Previous studies in breast and bladder cancer have suggested that epidermal growth factor receptor is expressed by only a proportion of cancers and is associated with poor clinical outcome. We used a monoclonal antibody specifically reactive with the extracellular domain of the epidermal growth factor receptor to localize this receptor immunohistochemically in frozen sections of normal ovary and epithelial ovarian cancer. Normal ovarian epithelium was found to express epidermal growth factor receptor in all cases. Among 87 ovarian cancers, however, 23% did not express immunohistochemically detectable receptor. Epidermal growth factor receptor expression was not related to histologic grade or stage, but was associated with poor survival (p less than 0.05). The median length of survival of patients with tumors that did not express epidermal growth factor receptor was 40 months compared with 26 months in patients with tumors that did express epidermal growth factor receptor. As in breast and bladder cancer, expression of epidermal growth factor receptor in ovarian cancer appears to be a poor prognostic factor. 相似文献
53.
Secretion of extracellular matrix-degrading proteinases is increased in epithelial ovarian carcinoma
Tammy L. Moser Timothy N. Young Gustavo C. Rodriguez Salvatore V. Pizzo Robert C. Bast M. Sharon Stack 《International journal of cancer. Journal international du cancer》1994,56(4):552-559
The biochemical events associated with tumor invasion involve localized degradation of the basement membrane by tumor-associated proteinases. In this study, we have characterized the proteinase secretion profiles of 5 ovarian epithelial carcinoma cell lines (DOV 13, OVCA 420, OVCA 429, OVCA 432, OVCA 433) as well as normal ovarian epithelial cells. Immunocapture assays demonstrated that all 5 carcinoma cell lines produce both secreted and surface-associated plasminogen activator. Urinary-type plasminogen activator (u-PA) production was one order of magnitude greater than production of tissue-type plasminogen activator (t-PA). Furthermore, t-PA secretion by normal ovarian epithelial cells was not detectable, whereas u-PA production was 17-to 38-fold lower than in ovarian carcinoma cells. Western-blotting analysis demonstrated that u-PA was secreted as the single chain form (scu-PA) when cells were cultured in serum-free medium. Incubation of plasminogen with ovarian carcinoma cell-conditioned medium resulted in direct activation of the Zymogen to plasmin. Furthermore, following incubation of cells with plasminogen, plasmin was eluted from the cell surface, indicating that ovarian carcinoma cells contain binding sites for plasminogen/plasmin which are accessible to surface-associated plasminogen activators. In addition to plasminogen activators, metalloproteinases were also produced by DOV 13, OVCA 429 and OVCA 433 cells. DOV 13 cells produce a 68-kDa metalloproteinase similar to matrix metalloproteinase 2 (MMP-2) whereas a 92-kDa enzyme similar to MMP-9 is secreted by OVCA 429 and 433. Together, ovarian carcinoma-associated plasminogen activators and metalloproteinases catalyze the hydrolysis of the major basement membrane protein components, type-IV collagen, type-IV gelatin, laminin and fibronectin. The enhanced proteolytic capability of ovarian carcinoma cells relative to normal ovarian epithelium suggests a biochemical mechanism by which invasion and spread of ovarian epithelial carcinoma may be mediated. 相似文献
54.
An initial analysis of preoperative serum CA 125 levels in patients with early stage ovarian carcinoma 总被引:1,自引:1,他引:1
V R Zurawski R C Knapp N Einhorn P Kenemans R Mortel K Ohmi R C Bast R E Ritts G Malkasian 《Gynecologic oncology》1988,30(1):7-14
Preoperative serum CA 125 levels were determined for 36 patients with Stage I and II ovarian carcinoma. Levels ranged from 9 to 1962 U/ml with a mean of 216 U/ml. In Stage I patients, CA 125 levels averaged 133 U/ml and in Stage II patients 382 U/ml. Nine of 24 Stage I (38%) and 9 of 12 Stage II patients (75%) had CA 125 levels in excess of 65 U/ml in a population somewhat overrepresented in mucinous tumors. Patients with non-mucinous neoplasms had CA 125 elevations more often--in 75% of the cases--than those with mucinous tumors. A larger study will be required to more precisely estimate the fraction of early stage patients with elevated preoperative serum CA 125 levels; however, this investigation demonstrates an assay sensitivity minimally adequate to initiate a pilot evaluation of serum CA 125 levels in a population at risk for ovarian carcinoma. 相似文献
55.
Elevation of serum CA125 in carcinomas of the fallopian tube, endometrium, and endocervix 总被引:9,自引:0,他引:9
J M Niloff T L Klug E Schaetzl V R Zurawski R C Knapp R C Bast 《American journal of obstetrics and gynecology》1984,148(8):1057-1058
An immunoradiometric assay with the use of a monoclonal antibody can detect an antigenic determinant (CA125) in peripheral blood from more than 80% of patients with epithelial ovarian cancer. In this report elevated levels of CA125 were detected in serum from patients with adenocarcinomas of the fallopian tube, endometrium, and endocervix. Among patients with endometrial cancer, CA125 levels were elevated in recurrent or disseminated disease but not with tumors confined to the uterus. 相似文献
56.
Immunoadsorption of sensitized kidney transplant candidates immediately prior to surgery 总被引:5,自引:0,他引:5
Patients with anti-human leucocyte antigen (HLA) antibodies from previous transplantation, blood transfusion are highly sensitized and at risk to hyperacute renal graft loss. As these antibodies are identified to be of pathogenic importance, an effective removal may allow successful transplantation. Six 'high risk patients' [panel-reactive antibodies (PRA) >30% or retransplanted patients with an acutely rejected first graft within 6 months from surgery] were treated by protein A immunoadsorption (IA) immediately prior to transplantation. We treated the calculated plasma volume one to three times prior to surgery: mean 4600 mL (range 2100-10 200 mL). After transplantation we repeated the sessions according to antibody (Ab) recurrence, graft function and signs of rejection. The panel reactive Ab were reduced from mean 65% pre-IA (range 35-85) to lowest 15% (range 0-55). After the course they reappeared to 30% (range 0-90). Five of the six patients had no clinical signs of vascular rejection. At a follow-up of mean 54 months (+/-14) four grafts still function with a mean serum creatinine of 172 micromol/L (+/-57). Protein A IA is a safe and effective adjunct in the treatment of highly sensitized patients awaiting renal transplantation. The treatment immediately prior to operation can prevent hyperacute rejection and increases the graft survival in these patients. 相似文献
57.
Prepulse inhibition (PPI) of the acoustic startle response is a measure of sensorimotor gating and is decreased in neuropsychiatric diseases, including schizophrenia. Hippocampal involvement in PPI has been the subject of several studies, in particular, as aberrant hippocampal activity has been associated with schizophrenia. In rats, chemical stimulation of the ventral hippocampus reduced PPI, while normal PPI was found following hippocampal lesions, suggesting that ventral hippocampal overactivity is detrimental for PPI, but that normal hippocampal activity does not contribute substantially to PPI. In the present study, we investigated the importance of hippocampal activity for PPI by examining PPI in Wistar rats with temporarily decreased hippocampal activity, aiming to avoid compensatory processes that may occur with permanent lesions. Bilateral ventral or dorsal hippocampal infusions of the gamma-aminobutyric acid A (GABA(A)) receptor agonist muscimol (1 microg/side) or the sodium-channel blocker tetrodotoxin (TTX, 10 ng/side) reduced PPI. This reduction is probably neuroleptic-resistant since haloperidol and clozapine did not antagonize the muscimol-induced decreases in PPI. PPI reduction by muscimol inhibition or TTX inactivation of the dorsal or ventral hippocampus indicates that hippocampal activity contributes to sensorimotor gating, suggesting intact PPI after permanent hippocampal lesions to reflect compensatory processes. The data are discussed with respect to hippocampal dysfunction in schizophrenia. 相似文献
58.
59.
Urrutia G Serra C Bonfill X Bastús R;Grupo Trabajo para el Estudio del Cancer de Vejiga Urinaria en la Comarca del Valles Occidental 《Gaceta sanitaria / S.E.S.P.A.S》2002,16(4):291-297
AIM: To identify all incident cases of bladder cancer in the county of Vallès Occidental (Spain), describe their histopathological characteristics, and make comparisons with other Spanish and European areas. METHOD: The study was carried out from the Corporació Parc Taulí (Sabadell). All new cases of bladder cancer in residents of the county Vallès Occidental, a highly industrialised area of Catalonia (Spain), were included between 1992 and 1994. Incidence rates of bladder cancer were adjusted and were compared with adjusted incidence rates reported by registries in other Spanish and European countries. RESULTS: 485 new cases were identified. Transitional cell carcinomas predominated (95.5%). The majority of tumours were diagnosed in their initial stages, 75.9% being superficial and 62.6% well to moderately differentiated. Bladder cancer was more common in men than in women, but women presented tumours of worse prognosis. The mean age at diagnosis was also higher in women than men (71 vs. 66 years, p = 0.03). The adjusted incidence rate in men (52.2 cases/100,000) was among the highest of the observed areas, whereas for women (5.4 cases/100,000) was relatively low. CONCLUSIONS: The incidence of bladder cancer among men in Vallès Occidental is among the highest in Europe, and intermediate for women. The high male/female ratio seen in all Spanish areas could be attributed to the fact that women in Spain have been less exposed than men to the risk factors, or their exposure occurred more recently. 相似文献
60.
Rothkrantz-Kos S Drent M Vuil H De Boer M Bast A Wouters EF Roos D van Dieijen-Visser MP 《Sarcoidosis, vasculitis, and diffuse lung diseases : official journal of WASOG / World Association of Sarcoidosis and Other Granulomatous Disorders》2002,19(2):114-120
BACKGROUND AND AIM OF THE WORK: The glutathione system has a key role in the defence against oxidative stress. To function properly, this system needs NADPH to maintain glutathione (GSH) in its reduced form. We hypothesized that the clinical problems associated with sarcoidosis might be related to a decreased anti-oxidant defence and we therefore measured the activity of the NADPH-generating enzyme glucose-6-phosphate dehydrogenase (G6PD), the GSH-regenerating enzyme glutathione reductase (GR) and indirectly the level of NADPH in red blood cells from patients with sarcoidosis. METHODS: In a population of sarcoidosis (n = 88) patients, G6PD, GR and GR activity after incubation with chromate (GR-Cr) were measured in erythrocytes. A decreased concentration of NADPH was revealed by an increased GR-Cr (> 0.6 IU/g Hb). To exclude a mutation in the G6PD gene, sequencing was performed in cases with an abnormal GR-Cr. Sarcoidosis pulmonary disease severity was evaluated by means of laboratory data, radiographic staging, HRCT scoring, pulmonary function and exercise capacity testing. RESULTS: Fourteen (29.2%) females and one (2.5%) male demonstrated an increased GR-Cr test, indicative of a decreased NADPH level. Patients with an abnormal test result demonstrated also significantly increased ACE and GR values (p < 0.05). Only one female case (of 6 tested) appeared to have a mutation in the G6PD gene. CONCLUSION: In a considerable percentage of female patients with sarcoidosis, a decreased level of NADPH in the erythrocytes was found. 相似文献