全文获取类型
收费全文 | 4344篇 |
免费 | 433篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 34篇 |
儿科学 | 101篇 |
妇产科学 | 166篇 |
基础医学 | 632篇 |
口腔科学 | 95篇 |
临床医学 | 452篇 |
内科学 | 932篇 |
皮肤病学 | 63篇 |
神经病学 | 296篇 |
特种医学 | 163篇 |
外科学 | 591篇 |
综合类 | 62篇 |
一般理论 | 2篇 |
预防医学 | 484篇 |
眼科学 | 80篇 |
药学 | 308篇 |
中国医学 | 13篇 |
肿瘤学 | 320篇 |
出版年
2023年 | 51篇 |
2022年 | 76篇 |
2021年 | 138篇 |
2020年 | 88篇 |
2019年 | 107篇 |
2018年 | 136篇 |
2017年 | 112篇 |
2016年 | 109篇 |
2015年 | 137篇 |
2014年 | 188篇 |
2013年 | 244篇 |
2012年 | 358篇 |
2011年 | 364篇 |
2010年 | 188篇 |
2009年 | 156篇 |
2008年 | 277篇 |
2007年 | 290篇 |
2006年 | 255篇 |
2005年 | 261篇 |
2004年 | 256篇 |
2003年 | 214篇 |
2002年 | 186篇 |
2001年 | 41篇 |
2000年 | 23篇 |
1999年 | 27篇 |
1998年 | 34篇 |
1997年 | 23篇 |
1996年 | 20篇 |
1995年 | 24篇 |
1994年 | 23篇 |
1993年 | 29篇 |
1992年 | 20篇 |
1991年 | 17篇 |
1990年 | 22篇 |
1989年 | 16篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 15篇 |
1985年 | 16篇 |
1984年 | 26篇 |
1983年 | 16篇 |
1982年 | 20篇 |
1981年 | 22篇 |
1980年 | 18篇 |
1979年 | 15篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1975年 | 11篇 |
1974年 | 11篇 |
1973年 | 8篇 |
排序方式: 共有4794条查询结果,搜索用时 15 毫秒
61.
Tracy Y. Zhu James F. Griffith Ling Qin Vivian W. Y. Hung Tsz-Ning Fong Anthony W. Kwok Ping-Chung Leung Edmund K. Li Lai-Shan Tam 《Calcified tissue international》2012,91(5):343-355
We assessed the relationship of bone density and microarchitecture between hand, peripheral, and axial skeletal sites using high-resolution peripheral quantitative computed tomography (HR-pQCT) and dual-energy X-ray absorptiometry (DXA) in patients with rheumatoid arthritis (RA) and which factors influence these parameters. This was a cross-sectional study of 100 female patients (53.4?±?9.3?years) with RA. HR-pQCT scans at distal radius and the second metacarpal head were performed to assess cortical and trabecular volumetric bone mineral density (vBMD) and microarchitecture. DXA scans at the hip, lumbar spine, and ultradistal radius were performed to assess areal BMD. There was significant correlation in vBMD and microarchitectural parameters between the second metacarpal head and distal radius (r?=?0.201?0.628). Areal BMD at the axial skeleton was moderately associated with vBMD at the peripheral sites (r?=?0.354–0.558). Factors related to disease severity/chronicity significantly correlated with vBMD and microarchitecture at the distal radius and the second metacarpal head. Factors related to disease activity were more likely to correlate with vBMD and microarchitecture at the second metacarpal head but not those at the distal radius. HR-pQCT is a promising technique that is capable of providing detailed quantitative assessment of disease-associated periarticular bone loss at both cortical and trabecular bone compartments in patients with RA. Future longitudinal studies will be needed to investigate whether assessment by HR-pQCT can be used as a marker of disease activity and a predictor of disease progression in RA. 相似文献
62.
Functions of the splenic remnant after subtotal splenectomy for treatment of severe splenic injuries 总被引:12,自引:0,他引:12
BACKGROUND: To evaluate the clinical and laboratory characteristics of patients submitted to subtotal splenectomy during the immediate and late postoperative period. METHODS: The study was conducted on 34 patients, 25 of whom were submitted to subtotal splenectomy (group I), and 9 to total splenectomy without preservation of splenic tissue (group II), and on 22 patients with intact spleens (group III, control). The immediate and late postoperative complications were investigated. Hematological examinations were performed during the late postoperative period (red cell count, hemoglobin, platelets, total and segmented leukocytes, lymphocytes, and Howell-Jolly bodies). Immunoglobulins (IgA, IgM, and IgG) and total T lymphocytes (TTL), active T lymphocytes (ATL), and B lymphocytes were also determined. Splenic scintigraphy with (99m)Tc colloidal sulfur was performed. RESULTS: Groups I and III did not presented abnormal blood bodies and their hematological and immunological pattern were normal. None of the groups showed leukocytosis or thrombocytosis. Howell-Jolly bodies were observed only in group II, which also showed reduced IgM levels. Scintigraphy showed filtering splenic tissue in group I. CONCLUSIONS: We conclude that subtotal splenectomy is a good surgical alternative for serious distal spleen lesion or when the main splenic pedicle is injured. 相似文献
63.
Effect of exercise on serum sex hormones in men: a 12-month randomized clinical trial. 总被引:1,自引:0,他引:1
Vivian N Hawkins Karen Foster-Schubert Jessica Chubak Bess Sorensen Cornelia M Ulrich Frank Z Stancyzk Stephen Plymate Janet Stanford Emily White John D Potter Anne McTiernan 《Medicine and science in sports and exercise》2008,40(2):223-233
PURPOSE: The effect of exercise on androgens in middle-aged to older men is poorly understood, and it could have implications for several aspects of health. This analysis was conducted to examine the effects of long-term aerobic exercise on serum sex hormones in middle-aged to older men. METHODS: One hundred two sedentary men, ages 40-75 yr, were randomly assigned to a 12-month exercise intervention or a control group (no change in activity). The combined facility- and home-based exercise program consisted of moderate/vigorous-intensity aerobic activity for 60 min.d(-1), 6 d.wk(-1). Serum concentrations of testosterone, free testosterone, dihydrotestosterone (DHT), 3alpha-androstanediol glucuronide (3alpha-Diol-G), estradiol, free estradiol, and sex hormone-binding globulin (SHBG) were measured at baseline, 3, and 12 months. RESULTS: Exercisers trained a mean of 370 min.wk(-1) (102% of goal), with only two dropouts. Cardiopulmonary fitness (.VO(2max)) increased 10.8% in exercisers and decreased by 1.8% in controls (P < 0.001). DHT increased 14.5% in exercisers versus 1.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.6% above baseline in exercisers versus a 3.1% decrease in controls (P = 0.03). SHBG increased 14.3% in exercisers versus 5.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.9% above baseline in exercisers versus 4.0% in controls (P = 0.13). There were significant trends toward increasing DHT and SHBG, with greater increases in .VO(2max) at 3 and 12 months in exercisers. No statistically significant differences were observed for testosterone, free testosterone, 3alpha-Diol-G, estradiol, or free estradiol in exercisers versus controls. CONCLUSIONS: A year-long, moderate-intensity aerobic exercise program increased DHT and SHBG, but it had no effect on other androgens in middle-aged to older men. 相似文献
64.
Objective: Epithelioid angiomyolipoma (EAML) is a rare malignant variant of renal angiomyolipoma (AML). There were 34 cases of EAML reported
in 25 studies (including this present study) over the past decade. About 68% were females and 32% males. The mean age was
40.1 years, 53% developed metastatic disease after nephrectomy, and eight patients had TSC. All cases are reported positive
when stained with HMB-45 which also labels all classical AML. This study evaluates the use of Ki-67 (proliferation marker)
in the pathological diagnosis of EAML and distinction from classical AML.
Method: Immunohistochemical reactions for Ki-67 were generated on multiple representative blocks of tissue obtained from two cases
of HMB-45 positive EAML and four cases of classic AML and the percentage of positively staining cells estimated.
Results: Both cases of EAML were strongly positive for Ki-67 while all four classic AML were completely negative.
Conclusion: The Ki67 is a useful marker in which distinguishes the malignant epithelioid variant of AML from classic AML. 相似文献
65.
von Hippel-Lindau gene status and response to vascular endothelial growth factor targeted therapy for metastatic clear cell renal cell carcinoma 总被引:3,自引:0,他引:3
66.
Woo YJ Grand TJ Berry MF Atluri P Moise MA Hsu VM Cohen J Fisher O Burdick J Taylor M Zentko S Liao G Smith M Kolakowski S Jayasankar V Gardner TJ Sweeney HL 《The Journal of thoracic and cardiovascular surgery》2005,130(2):321-329
OBJECTIVE: Ischemic heart failure is an increasingly prevalent global health concern with major morbidity and mortality. Currently, therapies are limited, and novel revascularization methods might have a role. This study examined enhancing endogenous myocardial revascularization by expanding bone marrow-derived endothelial progenitor cells with the marrow stimulant granulocyte-monocyte colony-stimulating factor and recruiting the endothelial progenitor cells with intramyocardial administration of the potent endothelial progenitor cell chemokine stromal cell-derived factor. METHODS: Ischemic cardiomyopathy was induced in Lewis rats (n = 40) through left anterior descending coronary artery ligation. After 3 weeks, animals were randomized into 4 groups: saline control, granulocyte-monocyte colony-stimulating factor only (GM-CSF only), stromal cell-derived factor only (SDF only), and combined stromal cell-derived factor/granulocyte-monocyte colony-stimulating factor (SDF/GM-CSF) (n = 10 each). After another 3 weeks, hearts were analyzed for endothelial progenitor cell density by endothelial progenitor cell marker colocalization immunohistochemistry, vasculogenesis by von Willebrand immunohistochemistry, ventricular geometry by hematoxylin-and-eosin microscopy, and in vivo myocardial function with an intracavitary pressure-volume conductance microcatheter. RESULTS: The saline control, GM-CSF only, and SDF only groups were equivalent. Compared with the saline control group, animals in the SDF/GM-CSF group exhibited increased endothelial progenitor cell density (21.7 +/- 3.2 vs 9.6 +/- 3.1 CD34 + /vascular endothelial growth factor receptor 2-positive cells per high-power field, P = .01). There was enhanced vascularity (44.1 +/- 5.5 versus 23.8 +/- 2.2 von Willebrand factor-positive vessels per high-power field, P = .007). SDF/GM-CSF group animals experienced less adverse ventricular remodeling, as manifested by less cavitary dilatation (9.8 +/- 0.1 mm vs 10.1 +/- 0.1 mm [control], P = .04) and increased border-zone wall thickness (1.78 +/- 0.19 vs 1.41 +/- 0.16 mm [control], P = .03). (SDF/GM-CSF group animals had improved cardiac function compared with animals in the saline control group (maximum pressure: 93.9 +/- 3.2 vs 71.7 +/- 3.1 mm Hg, P < .001; maximum dP/dt: 3513 +/- 303 vs 2602 +/- 201 mm Hg/s, P < .05; cardiac output: 21.3 +/- 2.7 vs 13.3 +/- 1.3 mL/min, P < .01; end-systolic pressure-volume relationship slope: 1.7 +/- 0.4 vs 0.5 +/- 0.2 mm Hg/microL, P < .01.) CONCLUSION: This novel revascularization strategy of bone marrow stimulation and intramyocardial delivery of the endothelial progenitor cell chemokine stromal cell-derived factor yielded significantly enhanced myocardial endothelial progenitor cell density, vasculogenesis, geometric preservation, and contractility in a model of ischemic cardiomyopathy. 相似文献
67.
George Demiris Lawrence B. Afrin Stuart Speedie Karen L. Courtney Manu Sondhi Vivian Vimarlund Christian Lovis William Goossen Cecil Lynch 《J Am Med Inform Assoc》2008,15(1):8-13
Advances in information technology (IT) enable a fundamental redesign of health care processes based on the use and integration of electronic communication at all levels. New communication technologies can support a transition from institution centric to patient-centric applications. This white paper defines key principles and challenges for designers, policy makers, and evaluators of patient-centered technologies for disease management and prevention. It reviews current and emerging trends; highlights challenges related to design, evaluation, reimbursement and usability; and reaches conclusions for next steps that will advance the domain. 相似文献
68.
69.
70.
Irene Paganini Vivian Y Chang Gabriele L Capone Jeremie Vitte Matteo Benelli Lorenzo Barbetti Roberta Sestini Eva Trevisson Theo JM Hulsebos Marco Giovannini Stanley F Nelson Laura Papi 《European journal of human genetics : EJHG》2015,23(7):963-968
Schwannomatosis is characterized by the development of multiple non-vestibular, non-intradermal schwannomas. Constitutional inactivating variants in two genes, SMARCB1 and, very recently, LZTR1, have been reported. We performed exome sequencing of 13 schwannomatosis patients from 11 families without SMARCB1 deleterious variants. We identified four individuals with heterozygous loss-of-function variants in LZTR1. Sequencing of the germline of 60 additional patients identified 18 additional heterozygous variants in LZTR1. We identified LZTR1 variants in 43% and 30% of familial (three of the seven families) and sporadic patients, respectively. In addition, we tested LZTR1 protein immunostaining in 22 tumors from nine unrelated patients with and without LZTR1 deleterious variants. Tumors from individuals with LZTR1 variants lost the protein expression in at least a subset of tumor cells, consistent with a tumor suppressor mechanism. In conclusion, our study demonstrates that molecular analysis of LZTR1 may contribute to the molecular characterization of schwannomatosis patients, in addition to NF2 mutational analysis and the detection of chromosome 22 losses in tumor tissue. It will be especially useful in differentiating schwannomatosis from mosaic Neurofibromatosis type 2 (NF2). However, the role of LZTR1 in the pathogenesis of schwannomatosis needs further elucidation. 相似文献