全文获取类型
收费全文 | 8751篇 |
免费 | 603篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 252篇 |
妇产科学 | 248篇 |
基础医学 | 1342篇 |
口腔科学 | 181篇 |
临床医学 | 1025篇 |
内科学 | 1682篇 |
皮肤病学 | 241篇 |
神经病学 | 1158篇 |
特种医学 | 221篇 |
外科学 | 706篇 |
综合类 | 67篇 |
一般理论 | 9篇 |
预防医学 | 794篇 |
眼科学 | 300篇 |
药学 | 531篇 |
中国医学 | 20篇 |
肿瘤学 | 558篇 |
出版年
2023年 | 78篇 |
2022年 | 118篇 |
2021年 | 205篇 |
2020年 | 185篇 |
2019年 | 215篇 |
2018年 | 271篇 |
2017年 | 212篇 |
2016年 | 222篇 |
2015年 | 270篇 |
2014年 | 300篇 |
2013年 | 459篇 |
2012年 | 734篇 |
2011年 | 718篇 |
2010年 | 374篇 |
2009年 | 339篇 |
2008年 | 642篇 |
2007年 | 590篇 |
2006年 | 550篇 |
2005年 | 521篇 |
2004年 | 484篇 |
2003年 | 455篇 |
2002年 | 439篇 |
2001年 | 66篇 |
2000年 | 45篇 |
1999年 | 62篇 |
1998年 | 83篇 |
1997年 | 73篇 |
1996年 | 66篇 |
1995年 | 45篇 |
1994年 | 50篇 |
1993年 | 41篇 |
1992年 | 31篇 |
1991年 | 25篇 |
1990年 | 20篇 |
1989年 | 18篇 |
1988年 | 16篇 |
1987年 | 21篇 |
1986年 | 23篇 |
1985年 | 20篇 |
1984年 | 21篇 |
1983年 | 19篇 |
1982年 | 24篇 |
1981年 | 11篇 |
1980年 | 16篇 |
1978年 | 22篇 |
1977年 | 17篇 |
1976年 | 12篇 |
1975年 | 12篇 |
1971年 | 12篇 |
1968年 | 10篇 |
排序方式: 共有9377条查询结果,搜索用时 15 毫秒
61.
Nonoperative Management of Primary Colorectal Cancer in Patients With Stage IV Disease 总被引:12,自引:0,他引:12
Scoggins CR Meszoely IM Blanke CD Beauchamp RD Leach SD 《Annals of surgical oncology》1999,6(7):651-657
Background: Traditional teaching maintains that patients with primary colorectal adenocarcinoma require timely resection to prevent bleeding, perforation, or obstruction. The true benefits of primary tumor resection remain undocumented for patients presenting with metastatic disease, however. We postulated that resection of primary colorectal tumors could be avoided safely in a select population of asymptomatic colorectal cancer patients presenting with incurable stage IV disease.Methods: A retrospective review of the Vanderbilt University Hospital tumor registry was performed for the years 1985 to 1997. During this period, 955 patients presented for management of primary colorectal cancer. From this group, all patients with stage IV disease at the time of diagnosis were identified. Patients who initially underwent resection of their primary lesion were included in the resection group; those who underwent initial nonoperative primary tumor management were included in the nonresection group. Data were obtained regarding age, extent of disease, nonsurgical therapy, tumor-specific complications, and palliative surgical procedures. Surgery-free survival and overall survival were analyzed using the Kaplan-Meier method. For patients with liver metastases, hepatic tumor burden was defined as either H1 (<25% parenchymal replacement), H2 (25% to 50%), or H3 (>50%) disease.Results: Sixty-six patients were included in the resection group, and 23 patients with intact asymptomatic primary colorectal lesions were included in the nonresection group. Among patients with hepatic metastases, most of the patients in both groups had H1 disease. Ten patients in the resection group and 3 patients in the nonresection group presented with exclusively extrahepatic metastases. In the nonresection group, primary therapy included chemotherapy in 13 patients, external beam radiation therapy in 1 patient, and combination chemoradiation in 9 patients. The median survival in the nonresection group was 16.6 months. The 2-year actuarial survival was 18%, and the surgery-free survival was 91.3%. Only 2 of 23 patients (8.7%) managed without resection eventually developed obstruction at the primary tumor site requiring emergent diversion. There were no episodes of tumor-related hemorrhage or perforation. For the resection group, the operative morbidity was 30.3%, and the perioperative mortality rate was 4.6%. The median survival in the resection group was 14.5 months (P = 0.59, log-rank test vs. nonresection group).Conclusions: Selected patients with asymptomatic primary colorectal tumors who present with incurable metastatic disease may safely avoid resection of their primary lesions, with an anticipated low rate of hemorrhage, perforation, or obstruction before death from systemic disease. No survival advantage is gained by resection of an asymptomatic primary lesion in the setting of incurable stage IV colorectal cancer. 相似文献
62.
Mira Keyes William James Morris Ingrid Spadinger Cynthia Araujo Arthur Cheung Nick Chng Juanita Crook Ross Halperin Vince Lapointe Stacy Miller Howard Pai Tom Pickles 《Brachytherapy》2013,12(4):343-355
PurposeTo describe in detail British Columbia (BC) Cancer Agency (BCCA) Provincial Prostate Brachytherapy (PB) Quality Assurance (QA) Program.Methods and MaterialsThe BCCA PB Program was established in 1997. It operates as one system, unified and supported by electronic and information systems, making it a single PB treatment provider for province of BC and Yukon. To date, >4000 patients have received PB (450 implants in 2011), making it the largest program in Canada. The Program maintains a large provincial prospective electronic database with records on all patients, including disease characteristics, risk stratification, pathology, preplan and postimplant dosimetric data, follow-up of prostate-specific antigen, and toxicity outcomes.ResultsQA was an integral part of the program since its inception. A formal QA Program was established in 2002, with key components that include: unified eligibility criteria and planning system, comprehensive database, physics and oncologist training and mentorship programs, peer review process, individual performance outcomes and feedback process, structured continuing education and routine assessment of the program's dosimetry, toxicity and prostate-specific antigen outcomes, administration and program leadership that promotes a strong culture of patient safety. The emphasis on creating a robust, broad-based network of skilled providers has been achieved by the program's requirements for training, education, and the QA process.ConclusionsThe formal QA process is considered a key factor for the success of cancer control outcomes achieved at BCCA. Although this QA model may not be wholly transferable to all PB programs, some of its key components may be applicable to other programs to ensure quality in PB and patient safety. 相似文献
63.
Neuropsychological progress during 14 years after severe traumatic brain injury in childhood and adolescence 总被引:1,自引:0,他引:1
Objective: To investigate the impact of time since injury on neuropsychological and psychosocial outcome after serious TBI in childhood or adolescence.
Methods: The subjects were eight patients with serious TBI sustained at a mean age of 14 years who had been assessed neuropsychologically at 1, 7 and 14 years after TBI. A retrospective longitudinal design was chosen to describe the development in six neuropsychological domains on the basis of the assessments. Psychosocial data were gathered from clinical knowledge and a semi-structured interview 14 years after TBI.
Results: Performance of verbal IQ shows a declining trend over the three assessments, that the performance of attention and working memory is low and that verbal learning is the cognitive domain which exhibits the largest impairments. The main psychosocial result is that three of the eight subjects went from a school situation with no adjustments to adult life with early retirement.
Conclusions: Time since insult is an important factor when assessing outcome after TBI in childhood and adolescence and that assessment of final outcome should not be done before adulthood. 相似文献
Methods: The subjects were eight patients with serious TBI sustained at a mean age of 14 years who had been assessed neuropsychologically at 1, 7 and 14 years after TBI. A retrospective longitudinal design was chosen to describe the development in six neuropsychological domains on the basis of the assessments. Psychosocial data were gathered from clinical knowledge and a semi-structured interview 14 years after TBI.
Results: Performance of verbal IQ shows a declining trend over the three assessments, that the performance of attention and working memory is low and that verbal learning is the cognitive domain which exhibits the largest impairments. The main psychosocial result is that three of the eight subjects went from a school situation with no adjustments to adult life with early retirement.
Conclusions: Time since insult is an important factor when assessing outcome after TBI in childhood and adolescence and that assessment of final outcome should not be done before adulthood. 相似文献
64.
Radio-frequency tumor ablation: internally cooled electrode versus saline-enhanced technique in an aggressive rabbit tumor model 总被引:12,自引:0,他引:12
Boehm T Malich A Goldberg SN Reichenbach JR Hilger I Hauff P Reinhardt M Fleck M Kaiser WA 《Radiology》2002,222(3):805-813
PURPOSE: To compare two methods of radio-frequency (RF) ablation, saline enhancement technique and internally cooled electrodes, for the treatment of small breast cancers in an animal model--highly aggressive VX2 rabbit tumors surrounded by adipose tissue. MATERIALS AND METHODS: Twenty-seven tumors were implanted into retroperitoneal fat of 14 New Zealand White rabbits. RF ablation was performed with ultrasonographic (US) guidance after tumors had grown to 15 mm. Fourteen tumors in seven animals were treated with internally cooled electrodes (30-mm-tip single electrode, 60 W, 10 min); 13 tumors in seven animals, with saline enhancement (0.5 mL/min of saline, 25-mm tip, 30 W, 10 min). Autopsy and histopathologic assessment were performed 3 weeks after therapy. RESULTS: Real-time US of RF ablation was not possible with either method because of obscuration by the increasing hyperechogenicity of the tumor and the surrounding adipose tissue. Equivalent efficacy was demonstrated with the two methods. Significantly greater complications were observed with the saline technique: Free retroperitoneal fluid was detected in one of seven animals with internally cooled electrodes and in all seven animals with saline enhancement (P <.01). Damage to remote structures such as the kidney, spine muscle, and skin was observed at autopsy in one of seven animals with internally cooled technique versus five of seven with saline enhancement (P <.01). CONCLUSION: Given a lower complication rate and similar treatment efficacy in an animal tumor model, internally cooled RF electrode may be advantageous to adjuvant saline infusion for the minimally invasive treatment of breast tumors. 相似文献
65.
Reinhard Klingel Michael Schaefer Andreas Schwarting Frido Himmelsbach Ulrich Altes Ingrid Uhlenbusch-K?rwer Gerd Hafner 《Nephrology, dialysis, transplantation》2004,19(1):164-170
BACKGROUND: Treatment modalities of renal replacement therapy differ in their diffusive and convective mass transfer characteristics. It was the goal of this study to clarify whether an increase in convective mass transfer as performed with haemofiltration (HF) and haemodiafiltration (HDF) in comparison with high-flux haemodialysis (HD) is associated with an alteration in procoagulatory activity or with complement activation. METHODS: Ten stable chronic HD patients were monitored during 120 treatments in a randomized cross over design. A high-flux polysulfone dialyser (APS 900) was used for high-flux HD, pre-dilution HF and pre-dilution HDF. Constant flow of on-line substitution fluid for HF and HDF was 200 ml/min. The low molecular weight heparin (LMWH) enoxaparin was used for anticoagulation (i) as single bolus (50 IU/kg body weight, median 3700 IU) and (ii) as bolus of 1200 IU followed by a median continuous dose of 400 IU/h. Blood samples were collected before the LMWH bolus, after 10 min, 60 min, 120 min and at the end of treatment in venous and arterial blood lines to determine antiXa activity, thrombin-antithrombin-III complex (TAT), D-dimer and C5a generation. RESULTS: Net ultrafiltration did not significantly differ between HD, HF and HDF but total ultrafiltration in HF and HDF far exceeded total ultrafiltration in HD. With conditions of single bolus, or bolus and continuous anticoagulation with enoxaparin, after comparable treatment times (median duration 4.25 h), TAT and D-dimer generation at identical anti-Xa levels revealed significantly higher coagulation activity during HF and HDF, compared with high-flux HD as assessed by comparative area under the curve (AUC) analysis. Plasma concentration of C5a in venous bloodlines did not significantly differ during HD, HF and HDF. CONCLUSION: A higher convective mass transfer during HF and HDF, in comparison with high-flux HD caused by a greater total ultrafiltration volume was associated with increased procoagulatory activity in the extracorporeal circuit. Molecular markers assessing the activation of coagulation are appropriate to adjust the anticoagulation regime to high UF volumes in order to minimize bleeding risk and optimize patency of the extracorporeal circuit. 相似文献
66.
Increased response of renal perfusion to the antioxidant vitamin C in type 2 diabetes. 总被引:2,自引:0,他引:2
Christian Delles Markus P Schneider Sebastian Oehmer Ingrid Fleischmann Erwin F Fleischmann Roland E Schmieder 《Nephrology, dialysis, transplantation》2004,19(10):2513-2518
BACKGROUND: Reactive oxygen species play a major role in the development of endothelial dysfunction. It is as yet unspecified whether increased oxidative stress contributes to endothelial dysfunction of the renal vasculature in patients with type 2 diabetes. METHODS: Renal haemodynamics were studied in 20 patients with type 2 diabetes and arterial hypertension (age 62 +/- 5 years) and 20 non-diabetic hypertensive patients at baseline and following infusions of the nitric oxide synthase inhibitor, N(G)-monomethyl-L-arginine (L-NMMA; 4.25 mg/kg); the substrate of nitric oxide synthase, L-arginine (100 mg/kg); and the antioxidant, vitamin C (3 g, co-infused with L-arginine 100 mg/kg). RESULTS: The response of renal plasma flow (RPF) to L-NMMA (-54 +/- 62 and -45 +/- 42 ml/min/1.73 m(2); P = NS) and L-arginine (+46 +/- 36 and +49 +/- 25 ml/min/1.73 m(2); P = NS) was not different between diabetic and non-diabetic patients. In contrast, vitamin C induced a more pronounced increase in RPF in diabetic than in non-diabetic patients when co-infused with L-arginine (+71+/-47 and +43+/-33 ml/min/1.73 m(2); P<0.05). CONCLUSIONS: The difference in the response of renal perfusion to an antioxidant suggests increased formation of reactive oxygen species and thereby reduced nitric oxide bioavailability in the renal vasculature of patients with type 2 diabetes. 相似文献
67.
Ingrid Duguépéroux Gil Bellis Jean-Fran?ois Lesure Michel Renouil Hughes Flodrops Marc De Braekeleer 《Journal of cystic fibrosis》2004,3(3):185-188
BACKGROUND: The Reunion Island is a French administrative department located in the Indian Ocean between the islands of Madagascar and Mauritius. Its population is known to be at a high risk of cystic fibrosis (CF). METHODS: Data concerning all CF patients born at the Reunion Island was extracted from the French CF Registry. Twenty-eight DeltaF508/DeltaF508, 17 Y122X/DeltaF508, and 11 Y122X/Y122X were included in a genotype-phenotype study. RESULTS: The detection rate of the CFTR mutations was 83% among the CF patients born at the Reunion Island. Three CFTR mutations accounted for 75% of the detected CF alleles at the Reunion Island (DeltaF508, Y122X, and 3120 + 1G-->A.). The DeltaF508/DeltaF508, DeltaF508/Y122X, and Y122X/Y122X genotypes accounted for 60.2% of the CF patients. Patients carrying at least one Y122X mutation were pancreatic insufficient, had high sweat chloride values and significantly lower anthropometric measures. The mean anthropometric values in all three groups were lower that in the whole CF population followed in "continental" France. This may reflect the poor compliance and even the refusal of treatment noted by the clinicians. CONCLUSIONS: The distribution of CFTR mutations could be explained by the history of the Reunion Island: admixture of French settlers, African and Asian populations, founder effect and isolation followed by genetic drift. The Y122X allele appears to be associated with a severe phenotype. 相似文献
68.
History of psychosis and previous episodes as potential explanatory factors for neurocognitive impairment in first‐treatment bipolar I disorder 下载免费PDF全文
69.
IB de Groot AM Stiggelbout PJ van der Boog AG Baranski PJ Marang-van de Mheen;for the PARTNER-study group 《Transplant international》2012,25(9):967-975
Health related quality of life (HRQoL) of living kidney donors on average is good, but some donors experience a low HRQoL after donation. This study assessed the prevalence of reduced HRQoL and explored associations with pre‐ and post‐donation variables. 316 donors (response rate 74%) who donated a kidney between 1997 and 2009 filled in a questionnaire. HRQoL was measured using the Short‐Form 36; fatigue using the Multidimensional Fatigue Inventory; societal participation using the Utrecht Scale for Evaluation of Rehabilitation‐Participation. Donors on average had better HRQoL than the general population. However, 12% had a reduced physical (PCS) and 18% a reduced mental (MCS) HRQoL. Donors with reduced HRQoL reported greater fatigue (P < 0.01), lower societal participation (P < 0.01) and showed a trend towards statistical significance in experiencing more donor–recipient relationship changes (P = 0.07). Prior to donation, donors with reduced PCS had a higher BMI (P < 0.05) and more often smoked (P < 0.05). Donors with reduced MCS had higher expectations (P < 0.05). Reduced HRQoL is associated with higher BMI, smoking and higher expectations prior to donation. These results may be used to develop a screening instrument to select donors at high risk for reduced HRQoL. 相似文献
70.
Manuel Gomez del Moral Beatriz Aviles Ingrid K. Colberger Yolanda Campos-Martin Javier Suela Joaquin Alvarez M. Jesús Perez-Contin Ana Sánchez-Fructuoso Alberto Barrientos Eduardo Martinez-Naves 《Transplant international》2005,18(3):333-340
The main difference between cadaveric kidneys from donors with a heartbeat (HBD) and kidneys from nonheart-beating donors (NHBD) is related to warm ischemia/reperfusion time which constitutes an acute inflammatory process. On the contrary, brain death induces in HBD expression of pro-inflammatory adhesion molecules, making it important to evaluate this kind of molecules in both types of donors. Human renal biopsies from NHBD, HBD and normal kidneys (ischemia time = 0) were taken and frozen just before transplant. A semi-quantitative RT-PCR method was used to determine intracellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), lymphocyte function associated antigen (LFA-1), LFA-3, CD40, CD40 ligand (CD40L) and RANTES (regulated upon activation, normal T-cell expressed and secreted) gene expression. We have detected an elevated relative gene expression of ICAM-1, VCAM-1 and RANTES in NHBD biopsies compared with normal kidneys. In the case of RANTES, the gene expression from NHBD biopsies was higher than observed in HBD biopsies. The rest of genes were not augmented in any group. Preliminary data about early outcome of transplants indicates a correlation between pretransplant RANTES high gene expression levels and early post-transplant acute rejection. The gene expression of pro-inflammatory molecules like adhesion molecules and RANTES is augmented in kidneys from cadaveric NBD just before transplant. The expression is higher probably because of the prolonged warm ischemia period. A larger clinical study is necessary to clarify the effects of these variable expressions on the transplant outcome. 相似文献