全文获取类型
收费全文 | 2546714篇 |
免费 | 201004篇 |
国内免费 | 3862篇 |
专业分类
耳鼻咽喉 | 34593篇 |
儿科学 | 84211篇 |
妇产科学 | 72220篇 |
基础医学 | 370121篇 |
口腔科学 | 74535篇 |
临床医学 | 232299篇 |
内科学 | 492708篇 |
皮肤病学 | 55180篇 |
神经病学 | 206158篇 |
特种医学 | 98643篇 |
外国民族医学 | 713篇 |
外科学 | 374806篇 |
综合类 | 59468篇 |
现状与发展 | 5篇 |
一般理论 | 1060篇 |
预防医学 | 205339篇 |
眼科学 | 58355篇 |
药学 | 190775篇 |
9篇 | |
中国医学 | 4481篇 |
肿瘤学 | 135901篇 |
出版年
2018年 | 25216篇 |
2016年 | 21622篇 |
2015年 | 25055篇 |
2014年 | 34551篇 |
2013年 | 53065篇 |
2012年 | 71739篇 |
2011年 | 76223篇 |
2010年 | 44683篇 |
2009年 | 42882篇 |
2008年 | 72394篇 |
2007年 | 76912篇 |
2006年 | 77245篇 |
2005年 | 75299篇 |
2004年 | 73488篇 |
2003年 | 70427篇 |
2002年 | 68586篇 |
2001年 | 113898篇 |
2000年 | 117238篇 |
1999年 | 99578篇 |
1998年 | 27904篇 |
1997年 | 25386篇 |
1996年 | 25664篇 |
1995年 | 24725篇 |
1994年 | 23119篇 |
1993年 | 21778篇 |
1992年 | 81538篇 |
1991年 | 79634篇 |
1990年 | 77688篇 |
1989年 | 75246篇 |
1988年 | 69829篇 |
1987年 | 68721篇 |
1986年 | 65603篇 |
1985年 | 62982篇 |
1984年 | 47510篇 |
1983年 | 41402篇 |
1982年 | 24471篇 |
1981年 | 22059篇 |
1980年 | 20784篇 |
1979年 | 45467篇 |
1978年 | 32304篇 |
1977年 | 27220篇 |
1976年 | 25555篇 |
1975年 | 27175篇 |
1974年 | 33138篇 |
1973年 | 32204篇 |
1972年 | 29949篇 |
1971年 | 28101篇 |
1970年 | 26122篇 |
1969年 | 24743篇 |
1968年 | 22722篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Victoria L. Parker Matthew C. Winter John A. Tidy Barry W. Hancock Julia E. Palmer Naveed Sarwar Baljeet Kaur Katie McDonald Xianne Aguiar Kamaljit Singh Nick Unsworth Imran Jabbar Allan A. Pacey Robert F. Harrison Michael J. Seckl 《International journal of cancer. Journal international du cancer》2023,152(5):986-997
Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus. 相似文献
22.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion. 相似文献
23.
Raymond J. Chan RN PhD Vivienne E. Milch MBBS MHPol Fiona Crawford-Williams PhD Oluwaseyifunmi Andi Agbejule BRadTherapy Ria Joseph MNutrDiet Jolyn Johal BND Narayanee Dick BSc Matthew P. Wallen PhD Julie Ratcliffe PhD Anupriya Agarwal MBBS Larissa Nekhlyudov MD Matthew Tieu PhD Manaf Al-Momani BPharm Scott Turnbull PhD Rahul Sathiaraj MPH Dorothy Keefe MBBS MD Nicolas H. Hart PhD 《CA: a cancer journal for clinicians》2023,73(6):565-589
Patient navigation is a strategy for overcoming barriers to reduce disparities and to improve access and outcomes. The aim of this umbrella review was to identify, critically appraise, synthesize, and present the best available evidence to inform policy and planning regarding patient navigation across the cancer continuum. Systematic reviews examining navigation in cancer care were identified in the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Cumulative Index of Nursing and Allied Health (CINAHL), Epistemonikos, and Prospective Register of Systematic Reviews (PROSPERO) databases and in the gray literature from January 1, 2012, to April 19, 2022. Data were screened, extracted, and appraised independently by two authors. The JBI Critical Appraisal Checklist for Systematic Review and Research Syntheses was used for quality appraisal. Emerging literature up to May 25, 2022, was also explored to capture primary research published beyond the coverage of included systematic reviews. Of the 2062 unique records identified, 61 systematic reviews were included. Fifty-four reviews were quantitative or mixed-methods reviews, reporting on the effectiveness of cancer patient navigation, including 12 reviews reporting costs or cost-effectiveness outcomes. Seven qualitative reviews explored navigation needs, barriers, and experiences. In addition, 53 primary studies published since 2021 were included. Patient navigation is effective in improving participation in cancer screening and reducing the time from screening to diagnosis and from diagnosis to treatment initiation. Emerging evidence suggests that patient navigation improves quality of life and patient satisfaction with care in the survivorship phase and reduces hospital readmission in the active treatment and survivorship care phases. Palliative care data were extremely limited. Economic evaluations from the United States suggest the potential cost-effectiveness of navigation in screening programs. 相似文献
24.
Janitz Amanda E. Schraw Jeremy M. Xu Chao Lupo Philip J. 《Cancer causes & control : CCC》2022,33(3):483-488
Cancer Causes & Control - Congenital malformations are strong risk factors for childhood cancer. Our objective was to determine whether cancer survival differs by birth defect status among... 相似文献
25.
26.
Byrne Emma Abel Stephen Yu Alexander Shepard Matthew Karlovits Stephen M. Wegner Rodney E. 《Journal of neuro-oncology》2022,157(1):197-205
Journal of Neuro-Oncology - Adjuvant radiation is often used in patients with low grade gliomas with high-risk characteristics with a recommended dose of 45–54 Gy. We used the... 相似文献
27.
Tengzhi Liu Kathrine Røe Redalen Morten Karlsen 《Journal of labelled compounds & radiopharmaceuticals》2022,65(7):191-202
Cyclotron-produced copper-64 radioisotope tracers offer the possibility to perform both diagnostic investigation by positron emission tomography (PET) and radiotherapy by a theranostic approach with bifunctional chelators. The versatile chemical properties of copper add to the importance of this isotope in medicinal investigation. [64Cu][Cu (ATSM)] has shown to be a viable candidate for imaging of tumor hypoxia; a critical tumor microenvironment characteristic that typically signifies tumor progression and resistance to chemo-radiotherapy. Various production and radiosynthesis methods of [64Cu][Cu (ATSM)] exist in labs, but usually involved non-standardized equipment with varying production qualities and may not be easily implemented in wider hospital settings. [64Cu][Cu (ATSM)] was synthesized on a modified GE TRACERlab FXN automated synthesis module. End-of-synthesis (EOS) molar activity of [64Cu][Cu (ATSM)] was 2.2–5.5 Ci/μmol (HPLC), 2.2–2.6 Ci/μmol (ATSM-titration), and 3.0–4.4 Ci/μmol (ICP-MS). Radiochemical purity was determined to be >99% based on radio-HPLC. The final product maintained radiochemical purity after 20 h. We demonstrated a simple and feasible process development and quality control protocols for automated cyclotron production and synthesis of [64Cu][Cu (ATSM)] based on commercially distributed standardized synthesis modules suitable for PET imaging and theranostic studies. 相似文献
28.
29.
Xiumei Jiang Xiaowei Zhang Patrick Gray Jiwen Zheng Timothy R. Croley Peter P. Fu 《journal of environmental science and health part c-environmental carcinogenesis & ecotoxicology reviews》2019,37(2):116-131
Gold nanoparticles (Au NPs) hold great promise in food, industrial and biomedical applications due to their unique physicochemical properties. However, influences of the gastrointestinal tract (GIT), a likely route for Au NPs administration, on the physicochemical properties of Au NPs has been rarely evaluated. Here, we investigated the influence of GIT fluids on the physicochemical properties of Au NPs (5, 50, and 100?nm) and their implications on intestinal epithelial permeability in vitro. Au NPs aggregated in fasted gastric fluids and generated hydroxyl radicals in the presence of H2O2. Cell studies showed that GIT fluids incubation of Au NPs affected the cellular uptake of Au NPs but did not induce cytotoxicity or disturb the intestinal epithelial permeability. 相似文献
30.