首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2797篇
  免费   315篇
  国内免费   23篇
耳鼻咽喉   18篇
儿科学   70篇
妇产科学   30篇
基础医学   173篇
口腔科学   79篇
临床医学   331篇
内科学   1032篇
皮肤病学   123篇
神经病学   110篇
特种医学   333篇
外国民族医学   21篇
外科学   179篇
综合类   22篇
预防医学   362篇
眼科学   23篇
药学   106篇
肿瘤学   123篇
  2023年   50篇
  2022年   16篇
  2021年   18篇
  2020年   44篇
  2019年   25篇
  2018年   63篇
  2017年   38篇
  2016年   48篇
  2015年   64篇
  2014年   105篇
  2013年   140篇
  2012年   86篇
  2011年   91篇
  2010年   93篇
  2009年   119篇
  2008年   109篇
  2007年   135篇
  2006年   131篇
  2005年   106篇
  2004年   96篇
  2003年   83篇
  2002年   86篇
  2001年   98篇
  2000年   105篇
  1999年   81篇
  1998年   81篇
  1997年   102篇
  1996年   89篇
  1995年   72篇
  1994年   71篇
  1993年   66篇
  1992年   42篇
  1991年   39篇
  1990年   56篇
  1989年   63篇
  1988年   45篇
  1987年   55篇
  1986年   53篇
  1985年   49篇
  1984年   20篇
  1983年   17篇
  1982年   28篇
  1981年   32篇
  1980年   20篇
  1979年   20篇
  1978年   9篇
  1977年   16篇
  1976年   17篇
  1975年   12篇
  1969年   5篇
排序方式: 共有3135条查询结果,搜索用时 31 毫秒
991.
BACKGROUND: Specific elements of health care process and physician behavior have been shown to influence disenrollment decisions in HMOs, but not in outpatient settings caring for patients with diverse types of insurance coverage. OBJECTIVE: To examine whether physician behavior and process of care affect patients' intention to return to their usual health care practice. DESIGN: Cross-sectional patient survey and medical record review. SETTING: Eleven academically affiliated primary care medicine practices in the Boston area. PATIENTS: 2,782 patients with at least one visit in the preceding year. MEASUREMENT: Unwillingness to return to the usual health care practice. RESULTS: Of the 2,782 patients interviewed, 160 (5.8%) indicated they would not be willing to return. Two variables correlated significantly with unwillingness to return after adjustment for demographics, health status, health care utilization, satisfaction with physician's technical skill, site of care, and clustering of patients by provider: dissatisfaction with visit duration (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.4 to 7.4) and patient reports that the physician did not listen to what the patient had to say (OR, 8.8; 95% CI, 2.5 to 30.7). In subgroup analysis, patients who were prescribed medications at their last visit but who did not receive an explanation of the purpose of the medication were more likely to be unwilling to return (OR, 4.9; 95% CI, 1.8 to 13.3). CONCLUSION: Failure of physicians to acknowledge patient concerns, provide explanations of care, and spend sufficient time with patients may contribute to patients' decisions to discontinue care at their usual site of care.  相似文献   
992.
A 48 year old woman was referred to hospital for buccal discomfort. Physical examination showed a macroglossia and features of xerostomia. She was diagnosed as having primary Sjögren''s syndrome according to the criteria proposed by the European Community study group in 1993. Furthermore, a lower lip salivary gland biopsy showed amyloid deposits that were also seen in the stomach and in the bone marrow. Echocardiography was consistent with cardiac amyloidosis. Serum immunofixation identified a monoclonal IgGλ. As far as is known, this is the first report of systemic primary amyloidosis associated with Sjögren''s syndrome. The relation between these two disorders is discussed.

  相似文献   
993.
This article discusses ways to recognize and manage lymphomas and pseudolymphomas associated with drug exposure. Over the last 30 years, the classification of pseudolymphomas and lymphomas has undergone significant change, especially following the application of sophisticated immunostaining and gene rearrangement analysis. The term cutaneous pseudolymphomas (CPL) is a nonspecific term for a heterogeneous group of benign reactive T- or B-cell lymphoproliferative processes that simulate cutaneous lymphomas clinically or histologically. While pseudolymphomas are relatively rare diseases, their clinical and histological heterogeneity has led to multiple systems of categorization based on immunological factors, causative agents, presentation, and clinical course.  相似文献   
994.

Objective

Interleukin‐6 (IL‐6) and soluble IL‐6 receptor (sIL‐6R) activation of gp130 represents an alternative pathway for osteoclast development in inflammatory conditions. The goal of the present study was to investigate changes in sIL‐6R levels in response to the inflammatory cytokines IL‐1β and tumor necrosis factor α (TNFα) and to determine the role of TNFα‐converting enzyme (TACE) in this process.

Methods

Levels of sIL‐6R in the culture media of MG63 and SAOS‐2 osteoblast‐like cell lines after exposure to various agents were determined by immunoassay. TACE protein levels were measured by Western immunoblotting. Cells were transfected with small interfering RNA (siRNA) or with an expression plasmid for IL‐6R and TACE to determine the potential involvement of TACE in IL‐6R shedding.

Results

IL‐1β and TNFα increased the levels of sIL‐6R in the culture media of MG63 osteoblast‐like cells. This effect was not influenced by cycloheximide or 5,6‐dichlorobenzimidazole riboside but was markedly inhibited by the calcium chelator EGTA and by the TACE and matrix metalloproteinase inhibitor hydroxamate (Ru36156). IL‐1β and TNFα had no influence on the alternatively spliced form of IL‐6R RNA. Levels of sIL‐6R were reduced when MG63 cells were transiently transfected with TACE siRNA. Transfection of SAOS‐2 cells with expression plasmids for IL‐6R and TACE produced a dose‐dependent increase in sIL‐6R levels.

Conclusion

IL‐1β‐ and TNFα‐mediated induction of IL‐6R shedding in osteoblast‐like cells is at least partly dependent on TACE activation.
  相似文献   
995.
996.
AIM: Severe uveitis is potentially associated with visual impairment or blindness in young patients. Therapeutic strategies remain controversial. The efficacy of interferon alpha-2a (IFN-alpha2a) in severe uveitis, refractory to steroids and conventional immunosuppressive agents, was evaluated. PATIENTS AND METHODS: Patients were included after a major relapse of uveitis following corticosteroids and immunosuppressants. IFN-alpha2a (3 million units three times a week) was administered subcutaneously. Efficacy was assessed by improvement in visual acuity, decrease in vitreous haze, resolution of retinal vasculitis and macular oedema, assessed by fundus examination and fluorescein angiography, and decrease in oral prednisone threshold. RESULTS: 45 patients were included. Median age was 32.3 years (range 8-58) and sex ratio (F/M) was 0.66. Uveitis was associated with Beh?et's disease in 23 cases (51.1%) and with other entities in 22 cases (48.9%). Median duration of uveitis before interferon therapy was 34.9 months (range 3.4-168.7) and an average of 3.26 relapses following corticosteroids and immunosuppressants was noted. Uveitis was controlled in 82.6% of patients with Beh?et's disease and 59% of patients with other types of uveitis (p = 0.07). During a mean follow-up of 29.6 months (range 14-55), median oral prednisone threshold decreased significantly from 23.6 mg/day (range 16-45) to 10 mg/d (range 4-14) (p<0.001). Interferon was discontinued in 10 patients (22.2%) with Beh?et's disease and in four patients without Beh?et's disease. Relapses occurred in four and one cases, respectively. CONCLUSIONS: Interferon therapy appears to be an efficient strategy in severe and relapsing forms of Beh?et's disease but also in other uveitic entities. However, it seems to act more to suspend rather than cure the disease. Therefore, IFN-alpha2a may be proposed as a secondline strategy after failure of conventional immunosuppressants.  相似文献   
997.
BACKGROUND: Neonatal exanthema of bacterial origin is caused very rarely by Gram-negative bacilli. We report a case of neonatal maculopapular exanthema evocative of Klebsiella pneumoniae septicemia resulting from maternofetal infection. OBSERVATION: On the fourth day of life, a newborn infant presented incipient morbilliform maculopapular exanthema on the face. During delivery, the mother had presented hyperthermia and meconium was found in the amniotic fluid. Clinical examination of the newborn was normal. No clinically obvious site of entry of infection was seen. Laboratory tests revealed major inflammatory syndrome. Blood cultures were positive for K. pneumoniae, which was also found in blood cultures from the mother. Screening for other causes of infection was negative. Parenteral antibiotics for 10 days yielded favorable results with simultaneous resolution of the exanthema, normalization of laboratory values and negative blood cultures. DISCUSSION: Exanthemas of infectious origin are not associated with any specific organism. The most common causative micro-organisms are Listeria monocytogenes, B streptococci, colibacilli, and more rarely, staphylococci. There have been reports of a number of cases of neonatal septicemia due to Gram-negative bacilli responsible for maculopapular exanthemas but the causative organism was not identified. To our knowledge, Klebsiella pneumoniae has never been incriminated in the appearance of this type of rash via maternofetal transmission. Consequently, the presence of neonatal exanthema should prompt screening for sepsis, even in the absence of other evocative signs, and in particular in settings of apyrexia.  相似文献   
998.
BACKGROUND: Traditionally melanoma has been considered as a radioresistant tumor. However, recent observations regarding radiobiology and clinical response of melanoma have prompted physicians to re-evaluate the role of radiotherapy in the management of melanoma. Indeed, radiotherapy is frequently used in the treatment of metastatic melanoma but the role of this therapeutic approach in the primary tumor management is unclear. We report 4 cases of thick primary melanoma treated by interstitial brachytherapy. CASE REPORTS: Four patients (3 men, 1 woman; age: 73, 74, 79, 84 years), three with lentigo maligna melanoma and one with nodular melanoma, were treated exclusively by interstitial brachytherapy. The thickness of the 4 tumors was more than 3 mm. This treatment was chosen either because of the impossibility of conservative surgery or because of a contraindication for general anesthesia. Median follow-up was 48 months [18 to 65 months] and we did not observe any local tumor relapse. The cosmetic and functional results of this therapy were excellent. DISCUSSION: These four cases illustrate the possibility of obtaining good local control of thick primary melanoma by interstitial brachytherapy where surgery is impossible, although without challenging the standard surgical therapy for primary melanoma. Before our study, this treatment was used only in one study to treat melanoma patients. In this case however, interstitial brachytherapy was accompanied by surgery. Therefore, the findings reported here are the first to demonstrate the efficacy of this treatment when used as the sole treatment for primary melanoma. In conclusion, where surgery is difficult or impossible, interstitial brachytherapy may be used to treat primary melanoma with excellent local tumor control and a good cosmetic outcome.  相似文献   
999.
BACKGROUND: Superficial venous thrombophlebitis (SVT), often perceived as benign, can coexist with hypercoagulable states. Predisposing risk factors for SVT are similar to those observed for deep venous thrombosis. Association of eosinophilia with SVT is a rare situation that can reveal neoplasia, malignant blood disorders, or vasculitis, but it has never been described in hypereosinophilic syndrome (HES). We herein describe the clinical and biological features, outcome, and response to therapy of 3 patients with SVT associated with eosinophilia that revealed HES. OBSERVATIONS: Superficial venous thrombophlebitis was the initial manifestation of HES in all 3 patients. The mean eosinophil count at diagnosis was 2.4 x 10(3)/muL. All patients received corticosteroids and anticoagulants as the initial treatment, with marked improvement of SVT and return of the eosinophil count to reference limits. All patients experienced relapse and remained dependent on corticosteroid therapy. Two patients received interferon alfa with dramatic regression of SVT, allowing a decrease in the dose of corticosteroids. CONCLUSIONS: We report, to our knowledge, the first 3 cases of SVT related to HES. Superficial venous thrombophlebitis was difficult to treat, with dependence on corticosteroid therapy and partial efficacy of anticoagulant and antiplatelet therapy. Interferon alfa was effective in preventing relapse of SVT related to HES. Mechanisms implied in this thrombogenesis are multiple and remain speculative.  相似文献   
1000.
Periocular haemangiomas of infancy can cause severe and rapid ocular damage. Oral corticosteroids remain the front-line treatment to minimize the consequences of these haemangiomas. The aim of this report is to summarize our experience with pulse intravenous methylprednisolone as an alternative therapy for periocular haemangioma when visual prognosis is engaged. Fifteen infants, who presented periocular haemangioma with functional impact on vision, received 2 mg/kg methylprednisolone intravenously twice a day for 2 days. Following pulse therapy, 2 mg/kg/day prednisolone was given orally with gradual tapering. No further visual impact was noticed following pulse therapy. Two patients relapsed, needing new pulses or, in one case, vincristine. No serious side-effects were recorded. Pulse methylprednisolone therapy permitted a particularly rapid shrinkage of haemangiomas and a complete disappearance of their visual impact within 2 days. Apparently more rapid than the usual oral corticosteroids, pulse intravenous methylprednisolone decreases the risk of ocular complications, which correlates with the duration of the influence of haemangiomas.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号