全文获取类型
收费全文 | 3671篇 |
免费 | 242篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 110篇 |
妇产科学 | 68篇 |
基础医学 | 333篇 |
口腔科学 | 175篇 |
临床医学 | 409篇 |
内科学 | 880篇 |
皮肤病学 | 29篇 |
神经病学 | 246篇 |
特种医学 | 329篇 |
外科学 | 517篇 |
综合类 | 46篇 |
预防医学 | 328篇 |
眼科学 | 23篇 |
药学 | 177篇 |
中国医学 | 2篇 |
肿瘤学 | 242篇 |
出版年
2020年 | 31篇 |
2019年 | 35篇 |
2018年 | 59篇 |
2017年 | 30篇 |
2016年 | 41篇 |
2015年 | 69篇 |
2014年 | 63篇 |
2013年 | 126篇 |
2012年 | 132篇 |
2011年 | 127篇 |
2010年 | 95篇 |
2009年 | 84篇 |
2008年 | 149篇 |
2007年 | 141篇 |
2006年 | 136篇 |
2005年 | 146篇 |
2004年 | 143篇 |
2003年 | 122篇 |
2002年 | 129篇 |
2001年 | 128篇 |
2000年 | 130篇 |
1999年 | 101篇 |
1998年 | 53篇 |
1997年 | 42篇 |
1995年 | 41篇 |
1994年 | 39篇 |
1993年 | 32篇 |
1992年 | 72篇 |
1991年 | 96篇 |
1990年 | 83篇 |
1989年 | 88篇 |
1988年 | 98篇 |
1987年 | 77篇 |
1986年 | 75篇 |
1985年 | 72篇 |
1984年 | 61篇 |
1983年 | 34篇 |
1982年 | 29篇 |
1981年 | 34篇 |
1980年 | 33篇 |
1979年 | 54篇 |
1978年 | 44篇 |
1977年 | 45篇 |
1976年 | 40篇 |
1975年 | 37篇 |
1974年 | 44篇 |
1973年 | 40篇 |
1972年 | 38篇 |
1971年 | 29篇 |
1970年 | 32篇 |
排序方式: 共有3937条查询结果,搜索用时 31 毫秒
1.
Gorreja Frida Car Charles Rush Stephen T. A. Forsskl Sophia K. Hrtlova Anetta Magnusson Maria K. Bexe Lindskog Elinor Brjesson Lars G. Block Mattias Wick Mary Jo 《Inflammation》2022,45(4):1631-1650
Inflammation - Inflammasomes are intracellular protein complexes whose activation results in proinflammatory cytokines. Inflammasomes are implicated in Crohn´s disease (CD) pathogenesis, yet... 相似文献
2.
3.
Martina A. Steurer Jean Costello Rebecca J. Baer Scott P. Oltman Sky K. Feuer Tania Pacheco-Werner Elizabeth Rogers Marta M. Jankowska Jessica Block Molly McCarthy Matthew S. Pantell Christina Chambers Kelli K. Ryckman Laura L. Jelliffe-Pawlowski 《Paediatric and perinatal epidemiology》2020,34(2):130-138
4.
5.
Hassan Haji‐Valizadeh Li Feng Liliana E. Ma Daming Shen Kai Tobias Block Joshua D. Robinson Michael Markl Cynthia K. Rigsby Daniel Kim 《NMR in biomedicine》2020,33(5)
Retrospective electrocardiogram‐gated, 2D phase‐contrast (PC) flow MRI is routinely used in clinical evaluation of valvular/vascular disease in pediatric patients with congenital heart disease (CHD). In patients not requiring general anesthesia, clinical standard PC is conducted with free breathing for several minutes per slice with averaging. In younger patients under general anesthesia, clinical standard PC is conducted with breath‐holding. One approach to overcome this limitation is using either navigator gating or self‐navigation of respiratory motion, at the expense of lengthening scan times. An alternative approach is using highly accelerated, free‐breathing, real‐time PC (rt‐PC) MRI, which to date has not been evaluated in CHD patients. The purpose of this study was to develop a 38.4‐fold accelerated 2D rt‐PC pulse sequence using radial k‐space sampling and compressed sensing with 1.5 × 1.5 × 6.0 mm3 nominal spatial resolution and 40 ms nominal temporal resolution, and evaluate whether it is capable of accurately measuring flow in 17 pediatric patients (aortic valve, pulmonary valve, right and left pulmonary arteries) compared with clinical standard 2D PC (either breath‐hold or free breathing). For clinical translation, we implemented an integrated reconstruction pipeline capable of producing DICOMs of the order of 2 min per time series (46 frames). In terms of association, forward volume, backward volume, regurgitant fraction, and peak velocity at peak systole measured with standard PC and rt‐PC were strongly correlated (R2 > 0.76; P < 0.001). Compared with clinical standard PC, in terms of agreement, forward volume (mean difference = 1.4% (3.0% of mean)) and regurgitant fraction (mean difference = ?2.5%) were in good agreement, whereas backward volume (mean difference = ?1.1 mL (28.2% of mean)) and peak‐velocity at peak systole (mean difference = ?21.3 cm/s (17.2% of mean)) were underestimated by rt‐PC. This study demonstrates that the proposed rt‐PC with the said spatial resolution and temporal resolution produces relatively accurate forward volumes and regurgitant fractions but underestimates backward volumes and peak velocities at peak systole in pediatric patients with CHD. 相似文献
6.
Block MS Castellon P Zavala J 《Journal of the American Dental Association (1939)》2007,138(6):785-790
BACKGROUND: The authors present a case that demonstrates the efficient replacement of a fixed prosthesis after a patient's abutment tooth fractured and required extraction. The fractured tooth had a local infection, and the maxillary bone was low-density and limited in height. CASE DESCRIPTION: The authors removed the tooth and grafted the site with particulate bone, while concurrently placing two implants in the edentulous region. After four months, they placed one additional implant and secured a fixed provisional prosthesis within one week. CLINICAL IMPLICATIONS: The patient wanted to minimize the time that she would have to be without a fixed prosthesis. The authors met her expectations by using an accelerated treatment plan. 相似文献
7.
Prospective evaluation of implants connected to teeth 总被引:1,自引:0,他引:1
Block MS Lirette D Gardiner D Li L Finger IM Hochstedler J Evans G Kent JN Misiek DJ Mendez AJ Guerra L Larsen H Wood W Worthington P 《The International journal of oral & maxillofacial implants》2002,17(4):473-487
PURPOSE: This prospective clinical trial examined the effect on teeth and implants when rigidly or non-rigidly connected in a cross-arch model. MATERIALS AND METHODS: Thirty patients received 2 implants, 1 on each side of the mandible, and were restored with 3-unit fixed partial dentures connected either rigidly or non-rigidly to an abutment tooth. Patients were followed for at least 5 years post-restoration. RESULTS: Repeated-measures analysis revealed no significant difference in crestal bone loss at implants (rigid versus non-rigid methods). An overall significant difference (P < .001) was found comparing methods for teeth. Paired t tests revealed no significant differences in crestal bone levels for implants or teeth at the 5-year recall. Kaplan-Meier methods and the Cox proportional hazards model showed no differences between attachment methods with regard to success based on survival and bone loss criteria. During the 5-year recall period, 1 implant (rigid side) was removed. Four implants developed bone loss greater than 2 mm during the course of this trial. One tooth on the rigid side and 2 teeth on the non-rigid side had greater than 2 mm of crestal bone loss and were removed secondary to fractures. In all, 5 abutment teeth were removed, all of which had been treated with root canal therapy and fractured at the interface of the post within the tooth. There was no clear relationship of tooth fracture to attachment. Repeated-measures analysis of mobility values revealed no significant changes over the time course of this study, and paired t tests revealed no statistically significant differences between implants for mobility. Repeated-measures analysis and paired t tests for probing depth revealed no significant changes over the time course of this study. There were no significant differences in soft tissue indices for either attachment method. The percentage of patients who had measurable intrusion was 66% for the non-rigid group, and 44% for the rigid group; 25% of the non-rigid teeth had greater than 0.5 mm intrusion, compared with 12.5% for the rigid group. For the 2 time periods evaluated, there was no significant increase in intrusion over time. The non-rigid-side implant required more nonscheduled visits to treat problems than the rigid implant and the teeth. Discussion: Most patients were treated successfully with rigid or non-rigid attachment of implants to teeth. CONCLUSION: The high incidence of intrusion and non-scheduled patient visits suggest that alternative treatments without connecting implants to teeth may be indicated. 相似文献
8.
Adaptive remodeling of the rabbit temporomandibular joint following discectomy and dietary variations 总被引:1,自引:0,他引:1
This study evaluates the healing of the rabbit temporomandibular joint (TMJ) following discectomy in four groups of animals fed a ground diet for 3 consecutive months (group 1), a ground diet for 1 month followed by 2 months of a coarse diet (group 2), a ground diet for 6 consecutive months (group 3), or a ground diet for 3 months followed by a coarse diet for 3 months (group 4), in order to evaluate the effects of changing the diet texture following discectomy. After 3 and 6 months, histologic evaluation demonstrated that 1) an early hyperplastic response in the fibrocartilage regressed in the later period regardless of diet, and 2) switching the ground diet to a hard diet caused degenerative scores to increase after both 1 and 3 months. 相似文献
9.
R M Block R D Lewis J B Sheats S G Burke 《Oral surgery, oral medicine, and oral pathology》1978,45(2):282-292
After pulpal extirpation of twenty teeth in each of five dogs, these animals were primarily immunized intramuscularly by combining formocresol with the dog's own pulp (three dogs), saline solution with pulp (one dog) and injecting sheep erythrocytes (one dog). A sixth dog was used as a control for the Arthus skin test. Secondary immunizations were accomplished via the root canal every 7 days over a 28-day period. Arthus skin-test reactions demonstrated less of a response to the formocresol alone than when the dogs' pulp was conbined with this material. In vitro analysis of hemagglutinating antibody titer showed a tremendous increase when pulp was incubated with formocresol as compared to the saline-treated pulp. Therefore, dogs' pulp tissue became antigenically altered by the formocresol recognized by the host, and a specific humoral response resulted. 相似文献
10.