全文获取类型
收费全文 | 8779篇 |
免费 | 838篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 365篇 |
儿科学 | 596篇 |
妇产科学 | 388篇 |
基础医学 | 653篇 |
口腔科学 | 563篇 |
临床医学 | 825篇 |
内科学 | 1764篇 |
皮肤病学 | 238篇 |
神经病学 | 647篇 |
特种医学 | 427篇 |
外科学 | 1795篇 |
综合类 | 95篇 |
一般理论 | 1篇 |
预防医学 | 317篇 |
眼科学 | 289篇 |
药学 | 387篇 |
中国医学 | 25篇 |
肿瘤学 | 280篇 |
出版年
2024年 | 22篇 |
2023年 | 218篇 |
2022年 | 139篇 |
2021年 | 315篇 |
2020年 | 232篇 |
2019年 | 268篇 |
2018年 | 620篇 |
2017年 | 497篇 |
2016年 | 614篇 |
2015年 | 470篇 |
2014年 | 730篇 |
2013年 | 927篇 |
2012年 | 746篇 |
2011年 | 757篇 |
2010年 | 651篇 |
2009年 | 373篇 |
2008年 | 243篇 |
2007年 | 220篇 |
2006年 | 207篇 |
2005年 | 133篇 |
2004年 | 75篇 |
2003年 | 70篇 |
2002年 | 79篇 |
2001年 | 97篇 |
2000年 | 66篇 |
1999年 | 63篇 |
1998年 | 130篇 |
1997年 | 99篇 |
1996年 | 102篇 |
1995年 | 65篇 |
1994年 | 78篇 |
1993年 | 41篇 |
1992年 | 14篇 |
1991年 | 21篇 |
1990年 | 13篇 |
1989年 | 32篇 |
1988年 | 29篇 |
1987年 | 30篇 |
1986年 | 26篇 |
1985年 | 24篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 16篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1975年 | 9篇 |
排序方式: 共有9655条查询结果,搜索用时 0 毫秒
991.
Özkan B Karabaş LV Altıntaş Ö Tamer GS Yüksel N Çağlar Y 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》2012,47(3):264-268
PurposeTo investigate the association of age-related macular degeneration (AMD) with plasma antiphospholipid antibody levels.MethodsThis prospective study included 19 patients diagnosed as having dry-type AMD, 23 patients with exudative-type AMD, and 25 control subjects. Venous blood samples of the participants were obtained. Anticardiolipin antibodies (aCL) isotypes IgG and IgM were measured by means of an enzyme-linked immunosorbent assay. Lupus anticoagulant (LA) antibodies were measured by the dilute Russell viper venom time screen test.ResultsThe mean aCL IgG concentration in patients with exudative-type AMD was significantly higher than in patients with dry-type AMD and control subjects. The mean ± SE of aCL IgG levels in patients with exudative-type AMD and dry-type AMD and control subjects was 5.46 ± 1.26; 2.55 ± 0.78; and 0.32 ± 0.1, respectively. The mean aCL IgM levels and LA levels in the 3 groups were not statistically different.ConclusionsOur findings suggest that elevated levels of serum aCL, a risk factor for cardiovascular and cerebrovascular diseases, may be associated with exudative-type AMD. 相似文献
992.
993.
994.
Ozdemır R Sarı FN Tunay ZO Erdeve O Canpolat FE Oguz SS Uras N Dılmen U 《Eye (London, England)》2012,26(7):992-996
Aim
To evaluate the association between respiratory tract Ureaplasma urealyticum (Uu) colonization and development of retinopathy of prematurity (ROP) requiring treatment.Methods
The infants with birthweight (BW) ≤1250 g born in a third-level neonatal intensive care unit between March 2009 and May 2010 were prospectively identified. Nasopharyngeal swabs for Uu colonization were taken in postnatal first 3 days. Culture-positive patients were reevaluated on the twelfth day by nasopharyngeal swabs for Uu. The primary outcome was to define whether there was an association between respiratory tract Uu colonization and severe ROP requiring treatment. Independent sample''s t-test or Mann–Whitney U-test was used to compare continuous variables and Chi-square test or Fisher''s exact test for categorical variables. Multivariate (backward) logistic regression analysis was performed to simultaneously measure the influence of the independent variables with ROP as the dependent variable.Results
A total of 25 (12.1%) infants developed severe ROP requiring treatment among 206 infants who underwent ROP screening. Mean BW and gestational age of total cohort were 1013±159 g and 27.9±1.6 weeks, respectively. Multivariate analysis demonstrated that BW (OR: 0.64 (95% Cl 0.47–0.88); P=0.006), duration of mechanical ventilation (OR: 1.17 (95% Cl 1.06–1.28); P=0.001), premature rupture of membrane >18 h (OR: 3.83 (95% Cl 1.2–12.2); P=0.02), and Uu positivity in both cultures (OR: 5.02 (95% Cl 1.8–13.9); P=0.002) were independent risk factors for the development of severe ROP requiring treatment.Conclusions
Respiratory tract colonization with Uu was independently associated with severe ROP requiring treatment. 相似文献995.
We carried out this study to determine which symptoms women experienced according to menopause type and the relation of these symptoms to sexual functions. The patricipants of the study were 250 women who underwent natural menopause and 200 women who underwent surgical menopause. A questionnaire, the Menopause Rating Scale (MRS), and the Golombok Rust Inventory of Sexual Satisfaction (GRISS) provided data. According to the MRS, hot flushes and sweating problems were the most common experiences, and, according to the GRISS, sexual infrequency problems rated highest in both groups. There was a positive relationship between multiple sexual functioning problems and the perceived level of menopausal symptom intensity, especially in surgical menopause women. 相似文献
996.
Göksel Açar Elnur Alizade Anıl Avci Hakan Çakir Suleyman Çagan Efe Mehmet Emin Kalkan Mehmet Mustafa Tabakci Cuneyt Toprak Ibrahim Halil Tanboğa Ali Metin Esen 《The international journal of cardiovascular imaging》2014,30(3):543-548
Strain (S) and strain rate (SR) are known to be altered in diseases associated with right ventricular (RV) pressure/volume overload and RV myocardial dysfunction; however determinants of S/SR are incompletely understood. The aim of this study was to examine the effect of blood donation-mediated volume reduction on regional RV deformation in healthy young adults. Study population was composed of 61 consecutive healthy subjects who were volunteers for blood donation. All underwent standard echocardiography and two-dimensional S and SR imaging by speckle tracking before and after 450 mL blood donation. We found no change in RV lateral wall SR in all three segments. However, the S in the apical and mid segments of the RV lateral wall immediately decreased after blood donation [?26.2 ± 3.3 vs. ?23.2 ± 3.3 % (p < 0.0001) and ?28.2 ± 3.4 vs. ?27.1 ± 3.2 % (p = 0.009), respectively], whereas no change was observed in the basal segment. Moreover, changes in systolic S on the apical segment of the RV lateral wall before and after blood donation were significantly correlated with the changes in the RV size [end-diastolic area index, r = ? 0.369 (p = 0.003) and end-systolic area index, r = ? 0.319 (p = 0.012)] and changes in the stroke volume index [r = ? 0.436 (p < 0.001)]. Blood donation-mediated volume reduction in healthy subjects caused a regional difference in RV longitudinal deformation with the lower mid and apical S that was related to parameters of volume load severity. However, RV systolic SR was found to be resistant to the effects of volume depletion. 相似文献
997.
Mustafa Gür Murat Çaylı Hakan Uçar Zafer Elbasan Durmuş Yıldıray Şahin Mehmet Yavuz Gözükara Şahbettin Selek Nermin Yıldız Koyunsever Taner Şeker Caner Türkoğlu Onur Kaypaklı Nurten Aksoy 《The international journal of cardiovascular imaging》2014,30(5):889-895
High density lipoprotein (HDL), a powerful antioxidant, protects low density lipoprotein (LDL) particles against oxidative stress. By limiting LDL oxidation, HDL plays an important role in preventing atherosclerosis (AS). The antioxidant effect of HDL is mostly associated with the paraoxonase (PON1) activity. It has been known that increased aortic intima-media thickness (IMT) is an earlier marker AS than carotid IMT. We aimed to investigate the association between thoracic aortic IMT and serum PON1 activity. We studied 133 patients (mean age: 46.3 ± 8 years) who underwent transesophageal echocardiography (TEE) for various indications. The measurements of thoracic aortic IMT by TEE are classified into four grades (1, 2, 3 and 4). Serum PON1 activity was measured spectrophotometrically. Oxidative and anti-oxidative status was evaluated by measuring serum lipid hydroperoxide (LOOH), total anti-oxidant status (TAS). Serum PON1 activity was progressively decreasing from grade 1 IMT to grade 4 IMT (p < 0.001). However, serum LOOH was significantly lower and TAS was significantly higher in patients with grade 1 when compared with other grades. In multiple linear regression analysis, IMT was independently correlated with PON1 activity (β = ?0.495, p < 0.001), TAS level (β = ?196, p < 0.009), age (β = 0.145, p = 0.029) and LDL cholesterol level (β = 0.169, p = 0.009). Decreased PON1 activity was independently associated with the extent of thoracic AS. PON1 activity may play a role in pathogenesis of thoracic AS besides age, TAS and LDL cholesterol levels. 相似文献
998.
999.
Effect of Curcumin on Systemic T Helper 17 Cell Response; Gingival Expressions of Interleukin‐17 and Retinoic Acid Receptor‐Related Orphan Receptor γt; and Alveolar Bone Loss in Experimental Periodontitis
下载免费PDF全文
![点击此处可从《Journal of periodontology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Burcu Bakır Zuhal Yetkin Ay H. İbrahim Büyükbayram Duygu Kumbul Doğuç Dilek Bayram İ. Aydın Candan Ersin Uskun 《Journal of periodontology》2016,87(11):e183-e191
Background: Curcumin has anti‐inflammatory and antioxidant effects and is reported to have many biologic activities. The current study examines effect of curcumin on: 1) systemic T helper 17 (Th17) cell response; 2) gingival expressions of interleukin (IL)‐17 and retinoic acid receptor‐related orphan receptor (ROR) γt; and 3) alveolar bone loss (ABL) in experimental periodontitis. Methods: Thirty‐eight male albino Wistar rats were divided into four groups: 1) group 1 = periodontitis; 2) group 2 = periodontitis with curcumin treatment; 3) group 3 = periodontally healthy with curcumin treatment; and 4) group 4 = periodontally healthy. Curcumin was administered via oral gavage (30 mg/kg/d) for 15 days. After sacrifice via exsanguination, the following serum levels were determined using enzyme‐linked immunosorbent assay: 1) IL‐1β; 2) IL‐6; 3) IL‐17A; 4) IL‐23; and 5) transforming growth factor‐ β. Morphometric evaluation of ABL was conducted and expression levels of IL‐17 and RORγt in gingival tissues were evaluated immunohistochemically. Results: Group 2 had significantly lower ABL than group 1 (P <0.0125). Highest expression levels of IL‐17 and RORγt were observed in group 1 and were significantly higher than those in all other groups (P <0.0125). The only serum biochemical parameter significantly different among groups was level of IL‐23 (P <0.05). Serum IL‐23 levels were higher in groups 1 and 2 than groups 3 and 4 (P <0.0125); however, they were not significantly different for groups 1 and 2 (P >0.0125). Conclusion: Curcumin seems to be a promising host modulatory agent in periodontal disease pathogenesis regarding IL‐17/IL‐23 axis, with a decreasing effect on ABL and gingival expressions of IL‐17 and RORγt. 相似文献
1000.
Fracture Resistance of Premolars Restored Either with Short Fiber or Polyethylene Woven Fiber‐Reinforced Composite
下载免费PDF全文
![点击此处可从《Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.]》网站下载免费的PDF全文](/ch/ext_images/free.gif)