全文获取类型
收费全文 | 158855篇 |
免费 | 10818篇 |
国内免费 | 625篇 |
专业分类
耳鼻咽喉 | 1769篇 |
儿科学 | 3910篇 |
妇产科学 | 2622篇 |
基础医学 | 20968篇 |
口腔科学 | 3395篇 |
临床医学 | 15564篇 |
内科学 | 33634篇 |
皮肤病学 | 3244篇 |
神经病学 | 14633篇 |
特种医学 | 6973篇 |
外国民族医学 | 14篇 |
外科学 | 25235篇 |
综合类 | 1957篇 |
一般理论 | 109篇 |
预防医学 | 11817篇 |
眼科学 | 3313篇 |
药学 | 10138篇 |
中国医学 | 238篇 |
肿瘤学 | 10765篇 |
出版年
2023年 | 885篇 |
2022年 | 1486篇 |
2021年 | 3376篇 |
2020年 | 2081篇 |
2019年 | 3124篇 |
2018年 | 3595篇 |
2017年 | 2804篇 |
2016年 | 3141篇 |
2015年 | 3588篇 |
2014年 | 5094篇 |
2013年 | 6853篇 |
2012年 | 10349篇 |
2011年 | 11008篇 |
2010年 | 6313篇 |
2009年 | 6018篇 |
2008年 | 9752篇 |
2007年 | 10195篇 |
2006年 | 10101篇 |
2005年 | 10146篇 |
2004年 | 9311篇 |
2003年 | 8622篇 |
2002年 | 8275篇 |
2001年 | 2155篇 |
2000年 | 1846篇 |
1999年 | 2133篇 |
1998年 | 1927篇 |
1997年 | 1557篇 |
1996年 | 1336篇 |
1995年 | 1251篇 |
1994年 | 1126篇 |
1993年 | 1016篇 |
1992年 | 1295篇 |
1991年 | 1192篇 |
1990年 | 1031篇 |
1989年 | 973篇 |
1988年 | 911篇 |
1987年 | 884篇 |
1986年 | 883篇 |
1985年 | 865篇 |
1984年 | 924篇 |
1983年 | 795篇 |
1982年 | 960篇 |
1981年 | 860篇 |
1980年 | 728篇 |
1979年 | 654篇 |
1978年 | 646篇 |
1977年 | 533篇 |
1976年 | 515篇 |
1974年 | 513篇 |
1973年 | 450篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
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
53.
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
54.
55.
56.
Marilyn Hravnak Leslie A Hoffman Melissa I Saul Thomas G Zullo Julie F Cuneo Ronald V Pellegrini 《American journal of critical care》2004,13(6):499-507; discussion 508
BACKGROUND: Studies suggest that patients who undergo off-pump coronary artery bypass grafting (OPCABG) have fewer short-term complications and use fewer inpatient resources than do patients who undergo standard coronary artery bypass grafting (CABG) with extracorporeal circulation. However, dissimilarity between groups in risk factors for complications has hindered interpretation of results. OBJECTIVES: To compare the prevalence of selected complications (atrial fibrillation, stroke, reoperation, and bleeding) and inpatient resource utilization (length of stay, discharge disposition, total charges) between subjects undergoing primary isolated CABG or OPCABG who were matched with respect to key risk factors. METHODS: Retrospective, causal-comparative survey conducted in 1 center for 18 months. Patients who underwent primary isolated CABG or OPCABG were matched for sex, age (within 2 years), left ventricular ejection fraction (within 0.05), and graft-patient ratio (exact match) and compared for prevalence of new-onset atrial fibrillation, stroke, reoperation within 24 hours, and bleeding. Statistical analysis included Wilcoxon and t tests for paired comparisons. RESULTS: The sample (107 matched pairs) was 63% male, with a mean age of 66 (SD 9.5) years, a mean left ventricular ejection fraction of 0.51 (SD 0.13), and a mean graft-patient ratio of 3.41 (SD 0.74). The 2 groups did not differ significantly in New York Heart Association class (P = .43), Acute Physiology and Chronic Health Evaluation III score (P = .22), postoperative beta-blocker use (P = .73), or comorbid conditions. None of the complications examined differed significantly between pairs. CONCLUSION: Patients with comparable risk profiles have similar prevalences of selected complications after CABG and OPCABG. 相似文献
57.
Eser Tüfek?i Thomas E Merrill Maria R Pintado John P Beyer William A Brantley 《American journal of orthodontics and dentofacial orthopedics》2004,125(6):733-739
Teeth with white spot lesions (WSL) might be more prone to enamel loss during bracket debonding. This in vitro study compared enamel loss from teeth with (n = 14) and without (n = 14) WSL after polishing with low-speed finishing burs or disks (Sof-Lex, 3M ESPE, St Paul, Minn). Debonded surfaces were analyzed with a contact stylus profilometer, and digitized data were compared with baseline readings by using AnSur NT software (Regents, University of Minnesota, Minneapolis, Minn). Specimen surfaces were also examined with a scanning electron microscope. Two-way analysis of variance was performed to analyze the data. In teeth without WSL, the volume losses were 0.16 mm(3) for the bur group and 0.10 mm(3) for the disk group; the mean maximum depths were 47.7 microm for the bur group and 54.3 microm for the disk group. In teeth with WSL, the volume losses were 0.06 and 0.17 mm(3), and the mean maximum depths were 35.1 and 48.7 microm for the bur and disk groups, respectively. There were no significant differences in enamel loss between the 2 groups of teeth without WSL (P =.12). However, in teeth with WSL, the burs removed less enamel than the disks (P = 0.006). Scanning electron microscope examination showed that any damage on the enamel surface was usually located in the cervical third of the teeth. On most specimens, even though tooth surfaces appeared resin-free to the naked eye, there were remnants of it. The differences between groups were so small that they might be clinically insignificant. 相似文献
58.
59.
Ramified microglial cells were investigated in primary cultures of dissociated cerebral cortical tissue from rats. The identification of these cells was confirmed through immunohistochemical staining with 7 monoclonal antibodies selective for microglia. While there was significant variation in staining intensity with different antibodies, all stained the identified ramified cells; the antibodies OX-42 and ED1 yielded the most intense immunoreactivity. Based on distinctive morphological features, the microglia could be identified in living cultures where they were monitored using time-lapse video recording. This technique revealed extremely dynamic features of cellular plasticity and motility. Ramified microglia exhibited constant and rapid alterations in the size and shape of their cell body with an associated extension and retraction of processes; concomitantly, the cells moved about in a circumscribed area. These features of plasticity and motility were unique to this cell type, and correlated with OX-42 immunostaining. The microglia also possessed a differentially high level of pinocytotic activity; this too was correlated with OX-42 staining. From the nature of their morphological plasticity and motility, high pinocytosis, and cellular distribution, it is hypothesized that the ramified microglia specifically function as a system of fluid cleansing in normal brain tissue. 相似文献
60.