全文获取类型
收费全文 | 173467篇 |
免费 | 12072篇 |
国内免费 | 649篇 |
专业分类
耳鼻咽喉 | 1909篇 |
儿科学 | 4392篇 |
妇产科学 | 3002篇 |
基础医学 | 22894篇 |
口腔科学 | 3756篇 |
临床医学 | 17189篇 |
内科学 | 36209篇 |
皮肤病学 | 3515篇 |
神经病学 | 15944篇 |
特种医学 | 7470篇 |
外国民族医学 | 14篇 |
外科学 | 27685篇 |
综合类 | 2239篇 |
一般理论 | 127篇 |
预防医学 | 13081篇 |
眼科学 | 3682篇 |
药学 | 11254篇 |
3篇 | |
中国医学 | 246篇 |
肿瘤学 | 11577篇 |
出版年
2023年 | 931篇 |
2022年 | 1575篇 |
2021年 | 3561篇 |
2020年 | 2208篇 |
2019年 | 3325篇 |
2018年 | 3826篇 |
2017年 | 2959篇 |
2016年 | 3334篇 |
2015年 | 3804篇 |
2014年 | 5421篇 |
2013年 | 7318篇 |
2012年 | 11024篇 |
2011年 | 11760篇 |
2010年 | 6672篇 |
2009年 | 6363篇 |
2008年 | 10336篇 |
2007年 | 10808篇 |
2006年 | 10716篇 |
2005年 | 10685篇 |
2004年 | 9853篇 |
2003年 | 9176篇 |
2002年 | 8721篇 |
2001年 | 2596篇 |
2000年 | 2332篇 |
1999年 | 2528篇 |
1998年 | 2106篇 |
1997年 | 1669篇 |
1996年 | 1481篇 |
1995年 | 1386篇 |
1994年 | 1235篇 |
1993年 | 1145篇 |
1992年 | 1679篇 |
1991年 | 1537篇 |
1990年 | 1394篇 |
1989年 | 1310篇 |
1988年 | 1246篇 |
1987年 | 1196篇 |
1986年 | 1175篇 |
1985年 | 1189篇 |
1984年 | 1175篇 |
1983年 | 1000篇 |
1982年 | 1099篇 |
1981年 | 977篇 |
1980年 | 846篇 |
1979年 | 888篇 |
1978年 | 813篇 |
1977年 | 654篇 |
1976年 | 629篇 |
1974年 | 629篇 |
1973年 | 575篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Beth T McCreary Thomas E Joiner Norman B Schmidt Nicholas S Ialongo 《Journal of clinical child and adolescent psychology》2004,33(2):313-324
This study examined the structure and symptom correlates of perfectionism in a sample of 6th-grade, urban, African American children using the Child and Adolescent Perfectionism Scale (CAPS; Flett, Hewitt, Boucher, Davidson, & Munro, 2000). Confirmatory factor analysis showed inadequate fit of the original subscales. Exploratory factor analysis suggested 3 dimensions of perfectionism: A Socially Prescribed and a Self-Oriented-Critical factor were described as maladaptive, whereas a Self-Oriented-Striving factor was proposed as adaptive. Cross-sectional correlations among the perfectionism dimensions and symptoms of psychopathology fit well with the adaptive versus maladaptive model. In addition, Socially Prescribed Perfectionism showed a robust predictive relation to 7th-grade internalizing symptoms, especially depression, in boys. Results are discussed in the context of the cultural and socioeconomic characteristics of this African American sample and suggestions for future research are provided. 相似文献
62.
63.
Abstract – Aim: To evaluate the pulp and periodontal healing of laterally luxated permanent teeth. Material and methods: Patients presenting with lateral luxation of permanent teeth during 2001–2002 were enrolled in this clinical study. Laterally luxated teeth were repositioned and splinted with a TTS/composite resin splint for 4 weeks. Immediate (prophylactic) root‐canal treatment was performed in severely luxated teeth with radiographically closed apices. All patients received tetracycline for 10 days. Re‐examinations were performed after 1, 2, 3, 6, 12 and 48 months. Results: All 47 laterally luxated permanent teeth that could be followed over the entire study period survived. In 10 teeth (21.3%), a prophylactic root‐canal treatment was performed within 2 weeks following injury. The remaining 37 teeth showed the following characteristics at the 4‐year re‐examination: 19 teeth (51.4%) had pulp survival (no clinical or radiographic signs or symptoms), nine teeth (24.3%) presented with pulp canal calcification, and pulp necrosis was seen in another nine teeth (24.3%), within the first year after trauma. None of the teeth with a radiographically open apex at the time of lateral luxation showed complications. External root resorption was only seen in one tooth. Conclusions: Laterally luxated permanent teeth with incomplete root formation have a good prognosis, with all teeth surviving in this study. The most frequent complication was pulp necrosis that was only seen in teeth with closed apices. 相似文献
64.
65.
66.
Hillary R Bogner Mark S Cary Martha L Bruce Charles F Reynolds Benoit Mulsant Thomas Ten Have George S Alexopoulos 《The American journal of geriatric psychiatry》2005,13(10):861-868
OBJECTIVE: The authors described the influence of specific medical conditions on clinical remission and response of major depression (MDD) in a clinical trial evaluating a care-management intervention among older primary-care patients. METHODS: Adults age 60 years and older were randomly selected and screened for depression. Participants were randomly assigned to Usual Care or to an Intervention with a depression care-manager offering algorithm-based care for MDD. In all, 324 adults meeting criteria for MDD were included in these analyses. Remission and response was defined by a score on the Hamilton Rating Scale for Depression <10 and by a decrease from baseline of > or =50%, respectively. Medical comorbidity was ascertained through self-report. Cognitive impairment was defined by a score <24 on the Mini-Mental State Exam (MMSE). RESULTS: In Usual Care, rates of remission were faster in persons who reported atrial fibrillation (AF) than in persons who did not report AF and slower in persons who reported chronic pulmonary disease than in persons who did not report chronic pulmonary disease; rates of response were less stable in persons with MMSE <24 than in those with MMSE > or =24. In the Intervention condition, none of the specific chronic medical conditions were significantly associated with outcomes for MDD. CONCLUSIONS: Because disease-specific findings were observed in persons who received Usual Care but not in persons who received more intensive treatment in the Intervention condition, our results suggest that the association of medical comorbidity and treatment outcomes for MDD may be determined by the intensity of treatment for depression. 相似文献
67.
Eric T. Stoopler DMD res Pinto DMD Faizan Alawi DDS Sree Raghavendra DMD Ricardo Boyce Jr. DDS David Porter MD Thomas P. Sollecito DMD 《Special care in dentistry》2004,24(2):65-69
Acute myelogenous leukemia (AMU is a hematologic disorder that is characterized by an abnormal proliferation of immature myeloid cells. Granulocytic sarcomas are clusters of leukemic myeloid cells that may develop as a result of AML. Oral manifestations of AML are common and often involve enlargements of the gingiva and/or mucosal tissue from direct leukemia cell infiltration. We describe the case history of a 50-year-old man who had an ulcera-tive lesion of the oral mucosa that was determined to be a granulocytic sarcoma of AML-M0 subtype. The combination of both the subtype and clinical presentation of the leukemia makes this presentation unusual, and to the best of our knowledge, of a type that has not been previously reported in the literature. 相似文献
68.
Phase II clinical trials are performed to investigate whether a novel treatment shows sufficient promise of efficacy to justify its evaluation in a subsequent definitive phase III trial, and they are often also used to select the dose to take forward. In this paper we discuss different design proposals for a phase II trial in which three active treatment doses and a placebo control are to be compared in terms of a single‐ordered categorical endpoint. The sample size requirements for one‐stage and two‐stage designs are derived, based on an approach similar to that of Dunnett. Detailed computations are prepared for an illustrative example concerning a study in stroke. Allowance for early stopping for futility is made. Simulations are used to verify that the specified type I error and power requirements are valid, despite certain approximations used in the derivation of sample size. The advantages and disadvantages of the different designs are discussed, and the scope for extending the approach to different forms of endpoint is considered. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
69.
Thomas Höge 《Stress and health》2009,25(1):41-51
Against the theoretical background of the effort–recovery model and the action regulation theory, the author presents a cross‐sectional questionnaire study testing hypotheses about the relationship between work‐related time pressure, cognitive and emotional irritation, work–family conflict and psychosomatic complaints. Subjects were 576 female home care nurses. Results of a path analysis show that the relation of time pressure and psychosomatic complaints is partially mediated by experiencing a work–family conflict; also the relation of time pressure and work–family conflict is partially mediated by cognitive and emotional irritation. It is argued that cognitive and emotional irritation are fruitful concepts for a more comprehensive understanding of the relationship between work stressors and the development of strain‐based work–family conflict. Implications for the prevention of work–family conflict are outlined. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
70.