全文获取类型
收费全文 | 7228篇 |
免费 | 674篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 108篇 |
儿科学 | 240篇 |
妇产科学 | 176篇 |
基础医学 | 1202篇 |
口腔科学 | 169篇 |
临床医学 | 730篇 |
内科学 | 1474篇 |
皮肤病学 | 54篇 |
神经病学 | 703篇 |
特种医学 | 254篇 |
外科学 | 1032篇 |
综合类 | 121篇 |
一般理论 | 3篇 |
预防医学 | 518篇 |
眼科学 | 279篇 |
药学 | 451篇 |
中国医学 | 12篇 |
肿瘤学 | 405篇 |
出版年
2023年 | 36篇 |
2022年 | 66篇 |
2021年 | 155篇 |
2020年 | 99篇 |
2019年 | 159篇 |
2018年 | 162篇 |
2017年 | 119篇 |
2016年 | 141篇 |
2015年 | 158篇 |
2014年 | 215篇 |
2013年 | 273篇 |
2012年 | 423篇 |
2011年 | 496篇 |
2010年 | 273篇 |
2009年 | 230篇 |
2008年 | 459篇 |
2007年 | 525篇 |
2006年 | 465篇 |
2005年 | 434篇 |
2004年 | 474篇 |
2003年 | 380篇 |
2002年 | 358篇 |
2001年 | 53篇 |
2000年 | 56篇 |
1999年 | 61篇 |
1998年 | 90篇 |
1997年 | 66篇 |
1996年 | 61篇 |
1995年 | 58篇 |
1994年 | 67篇 |
1993年 | 52篇 |
1992年 | 46篇 |
1991年 | 36篇 |
1990年 | 30篇 |
1989年 | 31篇 |
1988年 | 34篇 |
1987年 | 32篇 |
1986年 | 37篇 |
1985年 | 37篇 |
1984年 | 27篇 |
1983年 | 41篇 |
1982年 | 55篇 |
1981年 | 61篇 |
1980年 | 49篇 |
1979年 | 31篇 |
1978年 | 38篇 |
1977年 | 36篇 |
1976年 | 33篇 |
1975年 | 33篇 |
1974年 | 32篇 |
排序方式: 共有7931条查询结果,搜索用时 15 毫秒
51.
Marleen M. van den Heuvel Edwin H.G. Oei Jeroen J.M. Renkens Sita M.A. Bierma-Zeinstra Marienke van Middelkoop 《The spine journal》2021,21(3):465-476
BACKGROUND CONTEXTSeveral spinal abnormalities have been studied using magnetic resonance imaging (MRI). However, in children these studies were sparsely performed in general populations. Examining young children's spines is important since the shape of the bone is largely determined during the growth spurt. Furthermore, it is so far unknown if associations between weight status and spinal abnormalities, which are known for adolescents and adults, are already present in young children.PURPOSEWe aimed to present the prevalence of structural abnormalities in the prepubertal pediatric spine on MRI and their association with measures of the children's body weight and body composition.STUDY DESIGNCross-sectional study embedded in a prospective population-based birth cohort study.PATIENT SAMPLEFor this study, participants from the Generation R Study were selected based on the availability of MRI data of the lumbar spine and accelerometry data at the age of 9 years.OUTCOME MEASURESThe presence of structural abnormalities of intervertebral discs and vertebrae was scored on MRI. The body mass index-standard deviation [BMI-SD] score was calculated from objectively measured weight and height, and body composition measurements were obtained by a dual-energy X-ray absorptiometry scan.METHODSA semiquantitative scoring tool to assess the intervertebral discs and vertebrae of the lumbar spine on conventional MRI was designed for this purpose. Proportions of children with spinal abnormalities on at least one lumbar vertebral level were presented. Logistic regression was used to analyze associations between abnormalities and weight and body composition. We declare not to have any financial conflicts of interests.RESULTSWe included 559 children (median age of 9.88 years (interquartile range 6.74–10.02), 48.5% boys). Most frequently observed abnormalities of the intervertebral discs were abnormal signal intensity (24.9%), decreased or collapsed disc height (37.6%), disc bulging (73.3%), and abnormal nuclear shape (29.1%). Vertebral endplate irregularities and lumbosacral transitional vertebrae were seen in respectively 40% and 9.3% of the participants. Except for disc bulging, all abnormalities were predominantly present at the L5 level. Only the presence of endplate irregularities was associated with a higher body weight (BMI SD score (odds ratio [OR] 1.50 [95% confidence interval [CI] 1.21–1.86]) and BMI SD change (OR 1.48 [95% CI 1.07–2.03])) and increased body mass values in body composition measurements (% body fat (OR 1.05 [95% CI 1.02–1.09), fat mass index (OR 1.23 [95% CI 1.09–1.39]), and fat-free mass index (OR 1.30 [95% CI 1.06–1.59])) in adjusted analyses.CONCLUSIONSStructural spinal abnormalities, especially disc bulging, endplate irregularities, and an abnormal disc height, are already present in children aged 9 years from a Dutch population-based cohort. Of those abnormalities, endplate irregularities are associated with various weight and body composition measurements. 相似文献
52.
53.
54.
Grannum R. Sant M.D. Angelo A. Ucci Jr. M.D. PH.D. Edwin M. Meares Jr. M.D. 《Urology》1983,21(6):632-634
A renal tumor developing in a patient receiving cyclophosphamide (Cytoxan) therapy for Wegener granulomatosis is reported. The tumor was similar histologically to the "immunoblastic" sarcoma that develops in renal allograft recipients as a complication of immunosuppressive therapy. This case report strengthens the cause and effect relationship between immunosuppressive drug usage and the subsequent development of neoplasia. 相似文献
55.
56.
Carlos M. Villaln Eduardo Ramírez‐San Juan Araceli Snchez‐Lpez Guadalupe Bravo Edwin W. Willems Pramod R. Saxena David Centurin 《Basic & clinical pharmacology & toxicology》2003,92(4):165-172
Abstract: The present study investigated the effects of dopamine on the canine external carotid circulation. One min. intracarotid artery (i.c.) infusions of dopamine (10–310 μg min.?1) produced dose‐dependent decreases in the canine external carotid conductance without affecting blood pressure or heart rate. This effect was mimicked by the D1/2‐like receptor agonist apomorphine (1–310 μg min?1), but not by the D2‐like receptor agonist, bromocriptine (31–310 μg min.?1). In contrast, fenoldopam (1–310 μg min.?1, intracarotid), a D1‐like receptor agonist, produced dose‐dependent increases in external carotid conductance. The vasoconstrictor response to dopamine was abolished after intravenous administration of the antagonists, phentolamine (α1/2; 2000 μg kg?1) or rauwolscine (α2; 100 μg kg?1), but remained unaffected after prazosin (α1; 100 μg kg?1) or haloperidol (D2‐like; 1000 μg kg?1). Interestingly, after phentolamine not only were the vasoconstrictor responses to dopamine abolished, but even a dose‐dependent vasodilator component was unmasked. These vasodilator responses to dopamine remained unchanged after intravenous haloperidol or propranolol (1000 μg kg?1 each). On the other hand, the vasodilator responses to fenoldopam, which remained unchanged after intravenous saline (0.1 ml kg?1), propranolol (1000 μg kg?1) or vagosympathectomy, were abolished by the D1‐like receptor antagonist, SCH‐23390 (10 μg kg?1). Lastly, the responses to dopamine and fenoldopam were not significantly altered after intraperitoneal pretreatment with reserpine (5 mg kg?1; ?24 hr). The above results suggest that the canine external carotid vasoconstrictor responses to dopamine: (i) are mainly mediated by α2‐adrenoceptors; and (ii) overshadow a vasodilator component, which involves vascular D1‐like receptors. 相似文献
57.
Anthony T C Chan Brigette B Y Ma Y M Dennis Lo S F Leung W H Kwan Edwin P Hui Tony S K Mok Michael Kam Lisa S Chan Samuel K W Chiu K H Yu K Y Cheung Karen Lai Maria Lai Frankie Mo Winnie Yeo Ann King Philip J Johnson Peter M L Teo Benny Zee 《Journal of clinical oncology》2004,22(15):3053-3060
PURPOSE: To assess the efficacy of neoadjuvant paclitaxel and carboplatin (TC) followed by concurrent cisplatin and radiotherapy (RT) in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) and to monitor treatment response with plasma Epstein-Barr virus (EBV) DNA. PATIENTS AND METHODS: Thirty-one patients with International Union Against Cancer stages III and IV undifferentiated NPC had two cycles of paclitaxel (70 mg/m2 on days 1, 8, and 15) and carboplatin (area under the curve 6 mg/mL/min on day 1) on a 3-weekly cycle, followed by 6 to 8 weeks of cisplatin (40 mg/m2 weekly) and RT at 66 Gy in 2-Gy fractions. Plasma EBV DNA was measured serially using the real-time quantitative polymerase chain reaction method. Results All patients completed planned treatment. Response to neoadjuvant TC was as follows: 12 patients (39%) achieved partial response (PR) and 18 achieved (58%) complete response (CR) in regional nodes; five patients (16%) achieved PR and no patients achieved CR in nasopharynx. At 6 weeks after RT, one patient (3%) achieved PR and 30 patients (97%) achieved CR in regional nodes, and 31 patients (100%) achieved CR in nasopharynx; 29 patients (93%) had EBV DNA level of less than 500 copies/mL. Neoadjuvant TC was well tolerated, and the most common acute toxicity of cisplatin plus RT was grade 3 mucositis (55%). At median follow-up of 33.7 months (range, 7 to 39.3 months), six distant and three locoregional failures occurred. Plasma EBV DNA level increased significantly in eight of nine patients who experienced treatment failure but did not increase in those who did not. The 2-year overall and progression-free survival rates were 91.8% and 78.5%, respectively. CONCLUSION This strategy was feasible and resulted in excellent local tumor control. Serial plasma EBV DNA provides a noninvasive method of monitoring response in NPC. 相似文献
58.
Bradley R Pieters Augustinus A M Hart Nicola S Russell Edwin P M Jansen Johannes L Peterse Jacques Borger Emiel J Th Rutgers 《Radiotherapy and oncology》2003,67(2):159-164
BACKGROUND AND PURPOSE: Interstitial implants for brachytherapy boost in the breast conserving therapy of breast cancer can be performed in two ways; implants during the tumor excision (per-operative implants) or after the external beam therapy (delayed interstitial implants). Differences in cosmetic outcome were investigated. PATIENTS AND METHODS: Cosmetic results in 47 patients having a per-operative implant were compared to 123 patients having a delayed interstitial implant in a matched case-control study. Cosmesis was scored on a four-point-scale varying from 0 (excellent) to 3 (poor). RESULTS: After mean follow-up of 63 months, three observers found no difference in cosmetic outcome between the two groups after adjustment for variables found to be related with cosmesis (difference in mean score 0.50, P=0.26). Implant volume at 100% isodose was not found to differ (P=0.084) between the per-operative group (mean 102 cm3, S.D. 34 cm3) and the delayed group (mean 93 cm3, S.D. 29 cm3). CONCLUSIONS: Performing per-operative implants has not led to smaller implants. The method of performing brachytherapy does not result in marked differences in cosmetic outcome. 相似文献
59.
Ruth Plummer Charlotte Rees Andrew Hughes Philip Beale Martin Highley Jose Trigo Sathyarathnarn Gokul Ian Judson Hilary Calvert Ann Jackman Fraser Mitchell Robert Smith Edwin Douglass 《Clinical cancer research》2003,9(4):1313-1322
PURPOSE: ZD9331 is a novel, direct-acting antifolate cytotoxic that does not require polyglutamation for activity, and is a specific thymidylate synthase inhibitor. This Phase I trial aimed to determine the maximum tolerated dose of ZD9331, given as a 30-min i.v. infusion on days 1 and 8 of a 21-day cycle. Pharmacokinetic parameters and tumor response were also assessed. EXPERIMENTAL DESIGN: A total of 71 patients, with a range of solid malignancies and refractory to standard therapies (44% had received > or =3 prior chemotherapy regimens), were treated. The most common malignancies were colorectal cancer (35% of patients) and ovarian cancer (31%). ZD9331 was escalated from 4.8 mg/m(2)/day. RESULTS: Dose-limiting toxicity occurred at 162.5 mg/m(2) ZD9331, with grade 4 thrombocytopenia, grade 4 neutropenia lasting > or =7 days, and grade 3 nonhematologic toxicity. Plasma clearance of ZD9331 was slow and dose-dependent; however, ZD9331 pharmacokinetics were nonlinear. Pharmacodynamics of ZD9331 were determined by measurement of plasma deoxyuridine, which increased at all of the dose levels; dose-related increases in plasma deoxyuridine were significant (P = 0.003) on day 5. Stable disease was observed in 37% of patients; 23% of ovarian cancer patients had a > or =50% reduction in CA125 levels. CONCLUSIONS: The maximum tolerated dose of this schedule was 130 mg/m(2). The toxicity profile at this dose was acceptable, with 7 of 28 patients treated developing grade 3/4 neutropenia and thrombocytopenia, 2 grade 4 diarrhea, and 2 grade 3/4 rash. This schedule was convenient and demonstrated activity in extensively pretreated patients; therefore, this is the recommended dose for study in Phase II trials. 相似文献
60.
Adjuvant immunization of HLA-A2-positive melanoma patients with a modified gp100 peptide induces peptide-specific CD8+ T-cell responses. 总被引:3,自引:0,他引:3
John W Smith Edwin B Walker Bernard A Fox Daniel Haley Ketura P Wisner Teri Doran Brenda Fisher Lisa Justice William Wood John Vetto Holden Maecker Annemiek Dols Sybren Meijer Hong-Ming Hu Pedro Romero W Gregory Alvord Walter J Urba 《Journal of clinical oncology》2003,21(8):1562-1573
PURPOSE: To measure the CD8+ T-cell response to a melanoma peptide vaccine and to compare an every-2-weeks with an every-3-weeks vaccination schedule. PATIENTS AND METHODS: Thirty HLA-A2-positive patients with resected stage I to III melanoma were randomly assigned to receive vaccinations every 2 weeks (13 vaccines) or every 3 weeks (nine vaccines) for 6 months. The synthetic, modified gp100 peptide, g209-2M, and a control peptide, HPV16 E7, were mixed in incomplete Freund's adjuvant and injected subcutaneously. Peripheral blood mononuclear cells obtained before and after vaccination by leukapheresis were analyzed using a fluorescence-based HLA/peptide-tetramer binding assay and cytokine flow cytometry. RESULTS: Vaccination induced an increase in peptide-specific T cells in 28 of 29 patients. The median frequency of CD8+ T cells specific for the g209-2M peptide increased markedly from 0.02% before to 0.34% after vaccination (P <.0001). Eight patients (28%) exhibited peptide-specific CD8+ T-cell frequencies greater than 1%, including two patients with frequencies of 4.96% and 8.86%, respectively. Interferon alfa-2b-treated patients also had significant increases in tetramer-binding cells (P <.0001). No difference was observed between the every-2-weeks and the every-3-weeks vaccination schedules (P =.59). CONCLUSION: Flow cytometric analysis of HLA/peptide-tetramer binding cells was a reliable means of quantifying the CD8+ T-cell response to peptide immunization. This assay may be suitable for use in future trials to optimize different vaccination strategies. Concurrent interferon treatment did not inhibit the development of a peptide-specific immune response and vaccination every 2 weeks, and every 3 weeks produced similar results. 相似文献