全文获取类型
收费全文 | 7154篇 |
免费 | 339篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 43篇 |
儿科学 | 117篇 |
妇产科学 | 85篇 |
基础医学 | 1343篇 |
口腔科学 | 96篇 |
临床医学 | 596篇 |
内科学 | 1120篇 |
皮肤病学 | 168篇 |
神经病学 | 882篇 |
特种医学 | 247篇 |
外科学 | 945篇 |
综合类 | 41篇 |
一般理论 | 2篇 |
预防医学 | 358篇 |
眼科学 | 239篇 |
药学 | 635篇 |
中国医学 | 10篇 |
肿瘤学 | 621篇 |
出版年
2023年 | 24篇 |
2022年 | 57篇 |
2021年 | 97篇 |
2020年 | 51篇 |
2019年 | 87篇 |
2018年 | 83篇 |
2017年 | 61篇 |
2016年 | 90篇 |
2015年 | 131篇 |
2014年 | 157篇 |
2013年 | 271篇 |
2012年 | 386篇 |
2011年 | 421篇 |
2010年 | 272篇 |
2009年 | 257篇 |
2008年 | 453篇 |
2007年 | 527篇 |
2006年 | 490篇 |
2005年 | 566篇 |
2004年 | 473篇 |
2003年 | 526篇 |
2002年 | 475篇 |
2001年 | 79篇 |
2000年 | 62篇 |
1999年 | 94篇 |
1998年 | 135篇 |
1997年 | 92篇 |
1996年 | 80篇 |
1995年 | 66篇 |
1994年 | 62篇 |
1993年 | 75篇 |
1992年 | 35篇 |
1991年 | 60篇 |
1990年 | 38篇 |
1989年 | 43篇 |
1988年 | 23篇 |
1987年 | 23篇 |
1986年 | 24篇 |
1985年 | 22篇 |
1984年 | 24篇 |
1983年 | 26篇 |
1982年 | 33篇 |
1981年 | 31篇 |
1980年 | 28篇 |
1978年 | 21篇 |
1977年 | 29篇 |
1976年 | 19篇 |
1975年 | 19篇 |
1974年 | 21篇 |
1971年 | 18篇 |
排序方式: 共有7548条查询结果,搜索用时 15 毫秒
91.
92.
Manfred Lessel MD Arnulf Thaler Peter Heilig Wolfgang Jantsch Viktor Scheiber 《Documenta ophthalmologica. Advances in ophthalmology》1991,76(4):323-333
In a series of 30 unilaterally pseudophakic patients, electroretinograms and electrooculograms were recorded 6 months postoperatively. The unoperated on fellow eyes served as controls High intraoperative retinal light exposure (3.4–7.3 mW/cm2, Zeiss OPMI 6 operating microscope) caused a substantial reduction of electrophysiologic potentials. Light protection prevented deterioration of electroretinogram and electro-oculogram potentials; reducing the bulb voltage, tilting the axis of illumination, filtering short wavelengths and the use of light shields resulted in 4-log-unit lower intensities (0.8–3.7 W/cm2).Abbreviations ACL
anterior chamber lens
- ECCE
extracapsular cataract extraction
- ICCE
intracapsular cataract extraction
- PCL
posterior chamber lens 相似文献
93.
Eckhard Jähde Karl-Heinz Glüsenkamp Manfred F. Rajewsky 《Cancer chemotherapy and pharmacology》1991,27(6):440-444
Summary The cytotoxicity of many alkylating anticancer drugs is increased at reduced intracellular pH (pHi). The therapeutic index of such agents could therefore be improved by lowering pHi in the target cells prior to their application. We have previously demonstrated that the formation of lactic acid can be selectively enhanced in malignant tissues via glucose-mediated stimulation of tumor cell glycolysis. However, the resulting reduction in pHi is partly compensated by the extrusion of H+ equivalents into the extracellular space, with pHi remaining closer to the physiological value than extracellular pH (pHe). For full exploitation of the proton-mediated increase in the cytotoxicity of alkylating agents, pHi should therefore be equilibrated with pHe in lactic acid-producing cells. In the present study we investigated the question as to whether nigericin, an H+/K+ antiporter enabling the entry into cells of H+ ions at low pHe, can be used to enhance the cytotoxic effect of mafosfamide (MAFO; a precursor of activated cyclophosphamide) on cultured M1R rat mammary carcinoma cells. At pHe 7.4, the cytotoxic effect of combined treatment with MAFO and nigericin was not superior to treatment with MAFO alone. At acidic pHe, however, MAFO cytotoxicity was potentiated by nigericin as indicated by the colony-forming capacity of M1R cells. For example, at pHe 6.2 (corresponding to the approximate mean aggregated pH in actively glycolyzing tumors), the colonyforming fraction of cells treated with a combination of MAFO and nigericin was 3×10–5 that of controls, as compared with a value of 5×10–2 found for cells exposed to MAFO alone. These results suggest that agents counteracting cellular mechanisms that control pHi may be candidate compounds for investigations aimed at the enhancement of alkylating drug cytotoxicity following glucosemediated pH reduction in malignant tumors in vivo.This work was supported by grants from the Dr. Mildred Scheel-Stiftung für Krebsforschung and by the Federal Ministry for Research and Technology (0318849 A) 相似文献
94.
Carsten Denkert Wilko Weichert Klaus-Jürgen Winzer Berit-Maria Müller Aurelia Noske Silvia Niesporek Glen Kristiansen Hans Guski Manfred Dietel Steffen Hauptmann 《Clinical cancer research》2004,10(16):5580-5586
PURPOSE: The human ELAV (embryonic lethal abnormal vision)-like protein HuR stabilizes a certain group of cellular mRNAs that contain AU-rich elements in their 3'-untranslated region. Cell culture studies have shown that the mRNA of cyclooxygenase (COX)-2 can be stabilized by HuR. EXPERIMENTAL DESIGN: To investigate a possible contribution of dysregulation of mRNA stability to the progression of cancer and to overexpression of COX-2, we studied expression of HuR in 208 primary breast carcinomas by immunohistochemistry. RESULTS: There were two different staining patterns of HuR in tumor tissue of breast carcinomas: nuclear expression was seen in 61% of cases; and an additional cytoplasmic expression was seen in 30% of cases. Expression of HuR was significantly associated with increased COX-2 expression; this association was particularly significant for cytoplasmic HuR expression (P < 0.0005). We further observed a significant association of cytoplasmic (P = 0.002) or nuclear HuR (P = 0.027) expression with increased tumor grade. Only 13% of the grade 1 carcinomas showed cytoplasmic expression of HuR, compared with 46% of the grade 3 carcinomas. There was no significant correlation between HuR expression and other clinicopathological parameters such as histological type, tumor size, or nodal status as well as patient survival. CONCLUSIONS: Our results suggest that overexpression of HuR in tumor tissue may be part of a regulatory pathway that controls the mRNA stability of several important targets in tumor biology, such as COX-2. Based on our results, additional studies are necessary to investigate whether HuR might be a potential target for molecular tumor therapy. 相似文献
95.
Katrin Lamszus Ulrike Ulbricht Jakob Matschke Marc A Brockmann Regina Fillbrandt Manfred Westphal 《Clinical cancer research》2003,9(4):1399-1405
PURPOSE: Vascular endothelial growth factor (VEGF)-A isa key mediator of angiogenesis in malignant gliomas. Soluble VEGF receptor 1 (sVEGFR-1) can complex VEGF-A and reduce its bioavailability. In several animal models sVEGFR-1 inhibited angiogenesis and tumor growth. We analyzed the levels of endogenous sVEGFR-1 in gliomas of different malignancy grades in relation to tumor vascularity and VEGF-A. EXPERIMENTAL DESIGN: The concentration of sVEGFR-1 was determined by ELISA in 104 gliomas and normal brain. Levels of sVEGFR-1 were compared with malignancy grade, microvessel density, and VEGF-A concentration. Effects of sVEGFR-1 on glioma extract-induced endothelial cell chemotaxis were analyzed in vitro. RESULTS: The concentration of sVEGFR-1 correlated with the malignancy grade and was 12-fold higher in glioblastomas than in diffuse astrocytomas (P < 0.001), with intermediate levels for anaplastic astrocytomas. VEGF-A levels were 30-fold higher (P < 0.001) in glioblastomas than in diffuse astrocytomas. The sVEGFR-1:VEGF-A ratio was 0.27 in glioblastomas and 0.70 in diffuse astrocytomas. Both sVEGFR-1 and VEGF-A correlated with microvessel density (P < 0.001) and with each other (P < 0.001); sVEGFR-1 and VEGF-A also correlated with each other when only glioblastomas were analyzed (P = 0.001). In vitro, recombinant sVEGFR-1 inhibited endothelial cell chemotaxis induced by tumor extracts. CONCLUSIONS: Although absolute levels of sVEGFR-1 are increased in the more malignant gliomas, the sVEGFR-1:VEGF-A ratio is decreased 2.6-fold in glioblastomas compared with diffuse astrocytomas, suggesting that the ensuing increased bioavailability of VEGF-A favors angiogenesis. The inhibition of tumor extract-induced endothelial chemotaxis by sVEGFR-1 suggests that sVEGFR-1 could be useful as an angiogenesis inhibitor in the specific context of human gliomas. 相似文献
96.
97.
Maspin expression is characteristic for cisplatin-sensitive ovarian cancer cells and for ovarian cancer cases of longer survival rates. 总被引:2,自引:0,他引:2
Pawel Surowiak Verena Materna Malgorzata Drag-Zalesinska Andrzej Wojnar Irina Kaplenko Marek Spaczyński Manfred Dietel Maciej Zabel Hermann Lage 《International journal of gynecological pathology》2006,25(2):131-139
High cytoplasmic expression of maspin was described in ovarian cancers of shorter survival rates. Until now, no relationship has been described between expression of maspin and sensitivity to cisplatin in ovarian cancers. This study aimed at examining the relationship between expression of maspin, detected by immunohistochemistry and clinical response to cisplatin in ovarian cancer cases as well as the in vitro sensitivity to cisplatin of 11 ovarian cancer cell lines. The analyzes were performed on 73 samples of ovarian cancer and on A2780P, A2780RCIS, CAOV-3, EFO 21, EFO 27, ES-2, Mdah 2774, OAW 42, OVCAR-3, PA-1, and SKOV-3 ovarian cancer cells. Cytoplasmic maspin expression in studied cells significantly correlated with cisplatin sensitivity. A significantly shorter overall survival and progression-free survival was associated with lower cytoplasmic maspin expression at first-look laparotomies and nuclear maspin expression and secondary cytoreductions. Higher nuclear maspin at first-look laparotomies expression was specific for cases of complete response. In the study, the elevated expression of maspin was shown to be typical for cisplatin-sensitive ovarian cancers. 相似文献
98.
Katrin Lamszus Marc A Brockmann Carmen Eckerich Peter Bohlen Chad May Ulrich Mangold Regina Fillbrandt Manfred Westphal 《Clinical cancer research》2005,11(13):4934-4940
PURPOSE: Inhibition of angiogenesis can influence tumor cell invasion and metastasis. We previously showed that blockade of vascular endothelial growth factor receptor-2 (VEGFR-2) with the monoclonal antibody DC101 inhibited intracerebral glioblastoma growth but caused increased tumor cell invasion along the preexistent vasculature. In the present study, we attempted to inhibit glioma cell invasion using a monoclonal antibody against the epidermal growth factor receptor (EGFR), which in the context of human glioblastomas, has been implicated in tumor cell invasion. In addition, we analyzed whether blockade of vascular endothelial (VE)-cadherin as a different antiangiogenic target could also inhibit glioblastoma angiogenesis and growth. EXPERIMENTAL DESIGNS: Nude mice who received intracerebral glioblastoma xenografts were treated using monoclonal antibodies against VEGFR-2 (DC101), EGFR (C225), and VE-cadherin (E4G10) either alone or in different combinations. RESULTS: Increased tumor cell invasion provoked by DC101 monotherapy was inhibited by 50% to 66% by combined treatment with C225 and DC101. C225 inhibited glioblastoma cell migration in vitro, but had no effect on the volume of the main tumor mass or on tumor cell proliferation or apoptosis in vivo, either alone or in combination with DC101. The anti-VE-cadherin monoclonal antibody E4G10 was a weaker inhibitor of tumor angiogenesis and growth than DC101, and also caused a weaker increase in tumor cell invasion. CONCLUSIONS: Inhibition of angiogenesis achieved by blocking either VEGFR-2 or VE-cadherin can cause increased glioma cell invasion in an orthotopic model. Increased tumor cell invasion induced by potent inhibition of angiogenesis with DC101 could be inhibited by simultaneous blockade of EGFR. 相似文献
99.
100.
Athanasia Apsemidou Kerstin Rauwolf Athanasios Tragiannidis Angela Brentrup Manfred Schiborr Karsten Becker Martina Ahlmann Andreas H. Groll 《Pediatric blood & cancer》2019,66(4)
Bartonella henselae, the causative agent of cat‐scratch disease, has been recognized to be responsible for a broad range of clinical syndromes. We report the case of a patient with disseminated B. henselae infection mimicking Langerhans cell histiocytosis at presentation and its successful management with neurosurgery, prolonged antibacterial therapy, and observation. 相似文献