全文获取类型
收费全文 | 11866篇 |
免费 | 806篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 57篇 |
儿科学 | 411篇 |
妇产科学 | 266篇 |
基础医学 | 1769篇 |
口腔科学 | 127篇 |
临床医学 | 1633篇 |
内科学 | 2215篇 |
皮肤病学 | 185篇 |
神经病学 | 1447篇 |
特种医学 | 249篇 |
外科学 | 1013篇 |
综合类 | 101篇 |
一般理论 | 18篇 |
预防医学 | 1402篇 |
眼科学 | 219篇 |
药学 | 765篇 |
中国医学 | 22篇 |
肿瘤学 | 803篇 |
出版年
2024年 | 19篇 |
2023年 | 117篇 |
2022年 | 164篇 |
2021年 | 395篇 |
2020年 | 205篇 |
2019年 | 346篇 |
2018年 | 362篇 |
2017年 | 253篇 |
2016年 | 260篇 |
2015年 | 318篇 |
2014年 | 424篇 |
2013年 | 664篇 |
2012年 | 986篇 |
2011年 | 964篇 |
2010年 | 477篇 |
2009年 | 455篇 |
2008年 | 773篇 |
2007年 | 807篇 |
2006年 | 731篇 |
2005年 | 698篇 |
2004年 | 677篇 |
2003年 | 620篇 |
2002年 | 589篇 |
2001年 | 79篇 |
2000年 | 50篇 |
1999年 | 86篇 |
1998年 | 134篇 |
1997年 | 117篇 |
1996年 | 91篇 |
1995年 | 72篇 |
1994年 | 67篇 |
1993年 | 68篇 |
1992年 | 38篇 |
1991年 | 45篇 |
1990年 | 26篇 |
1989年 | 39篇 |
1988年 | 38篇 |
1987年 | 26篇 |
1986年 | 44篇 |
1985年 | 23篇 |
1984年 | 41篇 |
1983年 | 41篇 |
1982年 | 51篇 |
1981年 | 47篇 |
1980年 | 35篇 |
1979年 | 19篇 |
1976年 | 15篇 |
1975年 | 12篇 |
1974年 | 17篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Fernandez AP Aronson S Toledano A Winkelmann J Saldivar J Feinstein SB 《Echocardiography (Mount Kisco, N.Y.)》1996,13(5):489-498
Videodensitometric analysis of myocardial contrast echocardiography is traditionally performed off line. Recently, an online contrast ultrasound analysis system, Acoustic Densitometry (Hewlett-Packard), was introduced. We compared pixel intensities acquired with Acoustic Densitometry to pixel intensities derived from videodensitometry. A tissue phantom was imaged in phase I using three transducer frequencies (2.5, 3.5, and 5.0 MHz). In phase II, an in vitro flowing tube model with various concentrations of Albunex® was imaged at two flow rates, 0.6 and 1.2 m/sec, and at two transducer frequencies, 2.5 and 3.5 MHz. The relationship between pixel intensities yielded by the two systems for identical ultrasound signals was determined with linear regression. Intensities derived with Acoustic Densitometry strongly correlated with those derived from the offline videodensitometry system. The intensities were related by a predictive multiplicative factor based on display characteristics of the two systems. These results suggest that semiquantitative, online perfusion analysis with Acoustic Densitometry is as sensitive as analysis offline with videodensitometry. 相似文献
52.
Dana M. Hartl Stéphane Hans Jacqueline Vaissière Daniel F. Brasnu 《European archives of oto-rhino-laryngology》2003,260(4):175-182
This study was designed to determine which objective acoustic or aerodynamic parameters allowed a homogeneous group of patients with unilateral vocal fold paralysis (UVFP) to be distinguished from an age-matched and smoking-matched control group and to search for linear correlations between the objective parameters and the subjective breathiness ratings. Eight patients with recent-onset UVFP and 12 controls were prospectively studied. The acoustic parameters measured for the vowel /a/ at a comfortable frequency and intensity were: jitter, shimmer, harmonics-to-noise ratio, cepstral peak prominence, the difference between the levels of the first two harmonics and the relative energy above 6 kHz. Aerodynamic parameters included the mean flow rate during a sustained /a/ and intraoral pressure during the production of the phoneme /pi/. The long-term average spectrum was calculated for 40 s of text, and the relative average energies in four frequency bands were compared. Six judges rated a mid-/a/ sample using a five-parameter scale with four levels of severity. Nonparametric statistical analysis revealed significant differences ( P<.05) between the UVFP group and the control group for 14 of the 19 parameters studied. Correlations between the objective parameters and perceived breathiness differed in the two groups. Correlations were not always as expected as based on previous literature reports. These measurements provided an objective qualification of voice in patients with UVFP and successfully distinguished them from the normal controls. The objective acoustic and aerodynamic measurements had generally low linear correlations with breathiness ratings in the control group. Higher correlations were seen in the UVFP group, in which breathiness was best correlated with airflow measurements. 相似文献
53.
Susan E Davidson Meriel P Burns Jacqueline A Routledge Ric Swindell 《Radiotherapy and oncology》2003,68(3):241-247
BACKGROUND AND PURPOSE: As there are few studies examining the impact of radiotherapy on sexuality, we assessed the effect of radiotherapy for carcinoma of the cervix on sexual health and the ability of the LENT system to assess sexual function. MATERIALS AND METHODS: Using the vagina and sexual dysfunction scales of the LENT SOMA scales, subjective scores were measured prospectively before initiation of radiotherapy for 89 women, and at the following times after the start of treatment: 21, 70, 200, 400, 600 and 800 days. RESULTS: There was considerable variation in pre-radiotherapy scores that was not related to disease stage (P=0.054), but was related to patient age (P=0.037, for the average vagina scores and P=0.039 for the maximum vagina scores) The scores were influenced by prior surgery (P<0.0005 for maximum and average vagina scores, P=0.042 average and 0.017 maximum sexual dysfunction scores). For 48 patients for whom data were available at the first three time points, the vagina scores decreased significantly by 70 days compared to pre-radiotherapy scores, but not for sexual dysfunction. There was heterogeneity in the pattern of changes of scores over time: for some women there was no change in vagina subsection score, some increased, and some decreased. CONCLUSIONS: The work has shown variation both in pre-treatment sexual function and in the pattern of changes seen following radiotherapy. Our questionnaire proved useful to score subjective sexual and vaginal problems as given in the LENT subjective scales. Further study is needed to assess the effectiveness of the scales in assessing late effects. 相似文献
54.
55.
Florence Perillat-Menegaux Jacqueline Clavel Marie-Fran?oise Auclerc André Baruchel Guy Leverger Brigitte Nelken No?l Philippe Danièle Sommelet Etienne Vilmer Denis Hémon 《Cancer epidemiology, biomarkers & prevention》2003,12(1):60-63
The association between a familial history of autoimmune disease and childhood acute leukemia was investigated in a French case-control study that, overall, was designed to assess the role of perinatal, infectious, environmental, and genetic factors in the etiology of childhood acute leukemia. Familial histories of autoimmune disease in first- and second-degree relatives were compared in 279 incident cases, 240 cases of acute lymphocytic leukemia (ALL) and 39 cases of acute non-lymphoblastic leukemia (ANLL), and 285 controls. Recruitment was frequency matched by age, gender, hospital, and ethnic origin. Odds ratios (OR) were estimated using an unconditional regression model taking into account the stratification variables, socioeconomic status, and familial structure. A statistically significant association between a history of autoimmune disease in first- or second-degree relatives and ALL (OR, 1.7; 95% confidence interval (CI), 1.0-2.8) was found. A relationship between thyroid diseases overall and ALL (OR, 2.0; 95% CI, 1.0-3.9) was observed. This association was more pronounced for potentially autoimmune thyroid diseases (Grave's disease and/or hyperthyroidism and Hashimoto's disease and/or hypothyroidism) (OR, 3.5; 95% CI, 1.1-10.7 and OR, 5.6; 95% CI, 1.0-31.1, respectively for ALL and ANLL), whereas it was not statistically significant for the other thyroid diseases (thyroid goiter, thyroid nodule, and unspecified thyroid disorders) (OR, 1.6; 95% CI, 0.7-3.5 and OR, 1.3; 95% CI, 0.2-7.0, respectively, for ALL and ANLL). The results suggest that a familial history of autoimmune thyroid disease may be associated with childhood acute leukemia. 相似文献
56.
Antineoplastic effects of partially HLA-matched irradiated blood mononuclear cells in patients with renal cell carcinoma. 总被引:11,自引:0,他引:11
Roger K Strair Dale Schaar Daniel Medina Mary B Todd Joseph Aisner Robert S DiPaola Jacqueline Manago Beth Knox Amanda Jenkinson Rachelle Senzon Christina Baker Dudek Liesel Marie Ciardella Mercy Kuriyan Arnold Rubin Edmund C Lattime 《Journal of clinical oncology》2003,21(20):3785-3791
PURPOSE: Vaccines, cytokines, and other biologic-based therapies are being developed as antineoplastic agents. Many of these agents are designed to induce an autologous immune response directed against the malignancy. In contrast, hematopoietic stem-cell transplantation is being developed as a form of allogeneic immunotherapy. This study tests the tolerance and antineoplastic activity of sequential infusions of partially HLA-matched allogeneic blood mononuclear cells (obtained from relatives) when administered outside of the context of a hematopoietic stem-cell transplantation. The cells are irradiated to prevent graft-versus-host disease. PATIENTS AND METHODS: Fifteen patients with relapsed or refractory malignancies for which no standard therapy was available were enrolled onto a clinical trial designed to assess the tolerability and antineoplastic effects of irradiated partially HLA-matched blood mononuclear cells obtained from relatives. RESULTS: There was disease regression in three patients with metastatic renal cell carcinoma during treatment. There was disease progression in six patients with metastatic renal cell carcinoma and two patients with metastatic melanoma during treatment. There was no change in disease state in several other patients. CONCLUSION: Irradiated allogeneic blood mononuclear cells administered outside the context of hematopoietic stem-cell transplantation may induce disease responses in patients with relapsed or refractory malignancies. Transfusion of irradiated allogeneic blood mononuclear cells should be developed further as a novel therapeutic antineoplastic approach. 相似文献
57.
The relationship between dietary fat intake and risk of colorectal cancer: evidence from the combined analysis of 13 case-control studies 总被引:3,自引:0,他引:3
Geoffrey R. Howe Kristan J. Aronson Enrique Benito Roberto Castelleto Jacqueline Cornée Stephen Duffy Richard P. Gallagher José M. Iscovich Jiao Deng-ao Rudolf Kaaks Gabriel A. Kune Susan Kune Hin P. Lee Marion Lee Anthony B. Miller Ruth K. Peters John D. Potter Elio Riboli Martha L. Slattery Dimitrios Trichopoulos Albert Tuyns Anastasia Tzonou Lyndsey F. Watson Alice S. Whittemore Anna H. Wu-Williams Zheng Shu 《Cancer causes & control : CCC》1997,8(2):215-228
The objective of this study was to examine the effects of the intakeof dietary fat upon colorectal cancer risk in a combined analysis of datafrom 13 case-control studies previously conducted in populations withdiffering colorectal cancer rates and dietary practices. Original datarecords for 5,287 cases of colorectal cancer and 10,470 controls werecombined. Logistic regression analysis was used to estimate odds ratios (OR)for intakes of total energy, total fat and its components, and cholesterol.Positive associations with energy intake were observed for 11 of the 13studies. However, there was little, if any, evidence of anyenergy-independent effect of either total fat with ORs of 1.00, 0.95, 1.01,1.02, and 0.92 for quintiles of residuals of total fat intake (P trend =0.67) or for saturated fat with ORs of 1.00, 1.08, 1.06, 1.21, and 1.06 (Ptrend = 0.39). The analysis suggests that, among these case-control studies,there is no energy-independent association between dietary fat intake andrisk of colorectal cancer. It also suggests that simple substitution of fatby other sources of calories is unlikely to reduce meaningfully the risk ofcolorectal cancer. 相似文献
58.
59.
60.
Nina Streefkerk Marianne J. Heins Jop C. Teepen Elizabeth A. M. Feijen Dorine Bresters Eline van Dulmen‐den Broeder Margriet van der Heiden‐van der Loo Marry M. van den Heuvel‐Eibrink Flora E. van Leeuwen Jacqueline J. Loonen Helena J. H. van der Pal Ccile M. Ronckers A. Birgitta Versluys Wim J. E. Tissing Joke C. Korevaar Leontien C. M. Kremer 《Pediatric blood & cancer》2019,66(8)