全文获取类型
收费全文 | 9326篇 |
免费 | 820篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 98篇 |
妇产科学 | 43篇 |
基础医学 | 576篇 |
口腔科学 | 344篇 |
临床医学 | 267篇 |
内科学 | 341篇 |
皮肤病学 | 6074篇 |
神经病学 | 152篇 |
特种医学 | 91篇 |
外科学 | 317篇 |
综合类 | 312篇 |
一般理论 | 1篇 |
预防医学 | 315篇 |
眼科学 | 903篇 |
药学 | 248篇 |
中国医学 | 44篇 |
肿瘤学 | 36篇 |
出版年
2023年 | 104篇 |
2022年 | 75篇 |
2021年 | 232篇 |
2020年 | 254篇 |
2019年 | 212篇 |
2018年 | 297篇 |
2017年 | 288篇 |
2016年 | 298篇 |
2015年 | 291篇 |
2014年 | 350篇 |
2013年 | 374篇 |
2012年 | 297篇 |
2011年 | 315篇 |
2010年 | 257篇 |
2009年 | 359篇 |
2008年 | 338篇 |
2007年 | 357篇 |
2006年 | 307篇 |
2005年 | 275篇 |
2004年 | 290篇 |
2003年 | 287篇 |
2002年 | 246篇 |
2001年 | 310篇 |
2000年 | 152篇 |
1999年 | 251篇 |
1998年 | 315篇 |
1997年 | 245篇 |
1996年 | 287篇 |
1995年 | 269篇 |
1994年 | 242篇 |
1993年 | 233篇 |
1992年 | 215篇 |
1991年 | 207篇 |
1990年 | 165篇 |
1989年 | 214篇 |
1988年 | 215篇 |
1987年 | 135篇 |
1986年 | 95篇 |
1985年 | 103篇 |
1984年 | 79篇 |
1983年 | 62篇 |
1982年 | 57篇 |
1981年 | 38篇 |
1980年 | 50篇 |
1979年 | 20篇 |
1978年 | 32篇 |
1977年 | 25篇 |
1976年 | 27篇 |
1975年 | 34篇 |
1974年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Hyperosmotic tear stimulates human corneal nerve endings, activates ocular immune response, and elicits dry-eye symptoms. A soft contact lens (SCL) covers the cornea preventing it from experiencing direct tear evaporation and the resulting blink-periodic salinity increases. For the cornea to experience hyperosmolarity due to tear evaporation, salt must transport across the SCL to the post-lens tear film (PoLTF) bathing the cornea. Consequently, limited salt transport across a SCL potentially protects the ocular surface from hyperosmotic tear. In addition, despite lens-wear discomfort sharing common sensations to dry eye, no correlation is available between measured tear hyperosmolarity and SCL-wear discomfort. Lack of documentation is likely because clinical measurements of tear osmolarity during lens wear do not interrogate the tear osmolarity of the PoLTF that actually overlays the cornea. Rather, tear osmolarity is clinically measured in the tear meniscus. For the first time, we mathematically quantify tear osmolarity in the PoLTF and show that it differs significantly from the clinically measured tear-meniscus osmolarity. We show further that aqueous-deficient dry eye and evaporative dry eye both exacerbate the hyperosmolarity of the PoLTF. Nevertheless, depending on lens salt-transport properties (i.e., diffusivity, partition coefficient, and thickness), a SCL can indeed protect against corneal hyperosmolarity by reducing PoLTF salinity to below that of the ocular surface during no-lens wear. Importantly, PoLTF osmolarity for dry-eye patients can be reduced to that of normal eyes with no-lens wear provided that the lens exhibits a low lens-salt diffusivity. Infrequent blinking increases PoLTF osmolarity consistent with lens-wear discomfort. Judicious design of SCL material salt-transport properties can ameliorate corneal hyperosmolarity. Our results confirm the importance of PoLTF osmolarity during SCL wear and indicate a possible relation between PoLTF osmolarity and contact-lens discomfort. 相似文献
2.
《Journal of cranio-maxillo-facial surgery》2022,50(3):225-229
The aim of this study was to investigate the clinical course of masticatory function recovery following arthrocentesis. Patients with a unilateral condylar head fracture who underwent arthrocentesis for therapeutic reasons were evaluated and compared with patients with a unilateral condylar head fracture who did not undergo arthrocentesis. At 3 months after treatment, the occlusal contact area and maximum bite force in patients with a fracture treated with arthrocentesis were greater than in those who did not receive arthrocentesis at the same time points, although the differences were not significant. Moreover, at 1 and 3 months following arthrocentesis, mean (±SD) occlusal contact area (1 month: 1.99 ± 0.55 mm2, p = 0.01; 3 months: 2.90 ± 1.36 mm2, p = 0.03) and maximum bite force (1 month: 82.45 ± 15.04 N, p = 0.01; 3 months: 101.11 ± 14.53 N, p = 0.01) on the fractured side in patients who underwent that treatment were significantly reduced when compared with those on the non-fractured side. The authors conclude that if the priority is to avoid open reduction and internal fixation, then the arthrocentesis approach might be a less invasive alternative, albeit with the price of a prolonged healing interval. 相似文献
3.
《Gait & posture》2021
BackgroundIncreasing the ankle plantar-flexion angle at initial contact (IC) during landing reduces the impact features associated with landing, such as the vertical ground reaction force and loading rate, potentially affecting the risk of anterior cruciate ligament (ACL) injury. However, the relationships between the ankle plantar-flexion angle at IC and the previously identified biomechanical factors related to noncontact ACL injury have not been studied.Research questionThus, the purpose of this study was to determine whether significant relationships exist between the ankle plantar-flexion angle at IC and the biomechanical factors related to noncontact ACL injury.MethodsThe peak anterior tibial shear force, peak external knee valgus moment, peak knee valgus angle, and combined peak external knee valgus plus tibial internal rotation moments were measured in 26 individuals while performing self-selected, single-leg landing. Pearson correlation analyses were performed to assess the relationships between the ankle plantar-flexion angle at IC and the biomechanical factors mentioned above.ResultsThe greater ankle plantar-flexion angle at IC was related to smaller the peak knee valgus moment (r = −0.5, p = 0.009) and the combined peak knee valgus plus internal rotation moments (r = −0.58, p = 0.001).SignificanceThese results suggest that large ankle plantar-flexion angle at IC might be associated with lesser loading of the knee frontal plane and altering the self-selective ankle angle may result in biomechanical changes associated with ACL injury risk. 相似文献
4.
5.
Alessio Danilo Inchingolo Angelo Michele Inchingolo Ioana Roxana Bordea Edit Xhajanka Donato Mario Romeo Mario Romeo Carlo Maria Felice Zappone Giuseppina Malcangi Antonio Scarano Felice Lorusso Ciro Gargiulo Isacco Grazia Marinelli Maria Contaldo Andrea Ballini Francesco Inchingolo Gianna Dipalma 《Materials》2021,14(5)
Many different osteotomy procedures has been proposed in the literature for dental implant site preparation. The osseodensification is a drilling technique that has been proposed to improve the local bone quality and implant stability in poor density alveolar ridges. This technique determines an expansion of the implant site by increasing the density of the adjacent bone. The aim of the present investigation was to evaluate the effectiveness of the osseodensification technique for implant site preparation through a literature review and meta-analysis. The database electronic research was performed on PubMed (Medline) database for the screening of the scientific papers. A total of 16 articles have been identified suitable for the review and qualitative analysis—11 clinical studies (eight on animals, three on human subjects), four literature reviews, and one case report. The meta-analysis was performed to compare the bone-to-implant contact % (BIC), bone area fraction occupied % (BAFO), and insertion torque of clockwise and counter-clockwise osseodensification procedure in animal studies. The included articles reported a significant increase in the insertion torque of the implants positioned through the osseodensification protocol compared to the conventional drilling technique. Advantages of this new technique are important above all when the patient has a strong missing and/or low quantity of bone tissue. The data collected until the drafting of this paper detect an improvement when the osseodensification has been adopted if compared to the conventional technique. A significant difference in BIC and insertion torque between the clockwise and counter-clockwise osseodensification procedure was reported, with no difference in BAFO measurements between the two approaches. The effectiveness of the present study demonstrated that the osseodensification drilling protocol is a useful technique to obtain increased implant insertion torque and bone to implant contact (BIC) in vivo. Further randomized clinical studies are required to confirm these pieces of evidence in human studies. 相似文献
6.
7.
We describe two cases of acute‐onset erythema, peeling, and pruritus or tenderness isolated to the palmar surface of the hands. A detailed exposure history revealed significant periods of contact with homemade slime; given the clinical findings and timing of exposure, acute contact dermatitis of the hands was suspected. Symptoms and clinical findings resolved after avoidance of the suspected causative contactants. There are few if any reported cases of contact dermatitis to homemade slime in the literature; this serves to highlight the importance of a thorough exposure history in the evaluation of hand dermatitis. 相似文献
8.
Platelets have diverse roles in immune processes in addition to their key functions in haemostasis and thrombosis. Some studies imply that platelets may be possibly related to the immune tolerance induction. However, the role of platelets in the development of immune tolerance is not fully understood. The purpose of this study was to investigate the role of platelets in the development of regulatory mechanisms responsible for cutaneous inflammation using a mouse model of low zone tolerance (LZT). Mice were treated with 2,4,6‐trinitro‐1‐chlorobenzene (TNCB) 8 times every other day for tolerance induction with administration of anti‐platelet antibody or control antibody during the tolerance induction phase every 3 days. After the treatment for the tolerance induction, mice were sensitized and then challenged with TNCB. The contact hypersensitivity (CHS) was significantly decreased at 24 hours after challenge in the mice with LZT than in those without LZT. Platelet depletion via administration of anti‐platelet antibody reversed the inhibition of CHS and reduced the frequency of Foxp3+ Tregs in the inflamed skin and draining lymph nodes in mice with LZT. In addition, repeated low‐dose skin exposure resulted in elevated plasma levels of transforming growth factor (TGF)‐β1. Interestingly, platelet depletion reduced plasma TGF‐β1 levels of mice with LZT. Furthermore, the CHS response was reduced by administration of recombinant TGF‐β1 during platelet depletion in mice with LZT. Administration of anti‐TGF‐β antibody reversed the inhibition of the CHS responses. These results suggest that platelets are involved in the induction of immune tolerance via the release of TGF‐β1. 相似文献
9.
Chandler W. Rundle Tracy Funk Ross M. Brockman Kathryn Schwarzenberger 《Pediatric dermatology》2019,36(4):517-519
A 12‐year‐old boy presented with severe, bilateral foot dermatitis. Extended patch testing was performed, revealing a significant positive reaction to mixed dialkyl thioureas. A thorough review of his history revealed that he was likely being exposed through his neoprene taekwondo shoes. After implementation of allergen avoidance measures, his dermatitis resolved. This case emphasizes awareness of potential allergen exposures and offers helpful avoidance strategies. 相似文献