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   6801篇
  免费   387篇
  国内免费   32篇
耳鼻咽喉   50篇
儿科学   114篇
妇产科学   115篇
基础医学   975篇
口腔科学   101篇
临床医学   607篇
内科学   1193篇
皮肤病学   352篇
神经病学   794篇
特种医学   359篇
外科学   908篇
综合类   55篇
预防医学   325篇
眼科学   123篇
药学   529篇
中国医学   30篇
肿瘤学   590篇
  2023年   36篇
  2022年   67篇
  2021年   122篇
  2020年   86篇
  2019年   98篇
  2018年   135篇
  2017年   131篇
  2016年   163篇
  2015年   211篇
  2014年   242篇
  2013年   279篇
  2012年   453篇
  2011年   447篇
  2010年   306篇
  2009年   282篇
  2008年   478篇
  2007年   497篇
  2006年   493篇
  2005年   474篇
  2004年   424篇
  2003年   426篇
  2002年   431篇
  2001年   92篇
  2000年   56篇
  1999年   93篇
  1998年   100篇
  1997年   77篇
  1996年   67篇
  1995年   42篇
  1994年   46篇
  1993年   40篇
  1992年   28篇
  1991年   14篇
  1990年   18篇
  1989年   19篇
  1988年   17篇
  1987年   16篇
  1986年   14篇
  1985年   13篇
  1984年   14篇
  1983年   13篇
  1982年   13篇
  1981年   10篇
  1980年   20篇
  1978年   14篇
  1977年   10篇
  1976年   14篇
  1975年   8篇
  1974年   10篇
  1973年   8篇
排序方式: 共有7220条查询结果,搜索用时 250 毫秒
991.
The records of 80 children with autoimmune hemolytic anemia (AHA) followed up in the same department between 1962 and 1971 were reviewed. The peak incidence was in the first 4 years of life. Predominance among males was noted. Two familial cases were observed. Two main clinical patterns were distinguished: an acute transient type and a prolonged chronic type. A statistically significant correlation was found between the presenting clinical, hematologic and immunologic features and the ultimate evolution of the disease into either clinical pattern. High titer cold agglutinins were very rarely observed. In no patient was an underlying malignant disease found. Although the onset was sometimes dramatic, all the patients with acute transient type recovered rapidly. The over-all mortality was 11.2 per cent. Cases were fatal exclusively among patients suffering from prolonged chronic type AHA associated with either thrombocytopenia or other disorders. Corticosteroid therapy was of constant effectiveness in transient cases but its results were variable in chronic cases. Sixteen patients with prolonged chronic type AHA underwent splenectomy. Response was favorable in patients with significant splenic sequestration of 51Cr-labeled red cells.  相似文献   
992.
Although Americans and foreigners alike tend to think of the U.S. health care system as being a "market-driven" system, the prices actually paid for health care goods and services in that system have remained remarkably opaque. This paper describes how U.S. hospitals now price their services to the various third-party payers and self-paying patients, and how that system would have to be changed to accommodate the increasingly popular concept of "consumer-directed health care."  相似文献   
993.
Vertebrate photoreceptor cells are polarized neurons highly specialized for light absorption and visual signal transduction. Photoreceptor cells consist of the light sensitive outer segment and the biosynthetic active inner segment linked by a slender connecting cilium. The function of mature photoreceptor cells is strictly dependent on this compartmentalization which is maintained in the specialized retinal environment. To keep this fragile morphologic and functional composition for further cell biological studies and treatments we established organotypic retina cultures of mature mice and Xenopus laevis. The organotypic retina cultures of both model organisms are created as co-cultures of the retina and the pigment epithelium, still attached to outer segments of the photoreceptor cells. To demonstrate the suitability of the culture system for physiological analyses we performed apoptotic cell death analyses and verified photoreceptor viability. Furthermore, light-dependent bidirectional movements of arrestin and transducin in photoreceptors in vivo and in the retinal cultures were indistinguishable indicating normal photoreceptor cell-biologic function in organotypic cultures. Our established culture systems allow the analysis of mature photoreceptor cells and their accessibility to treatments, characteristic for common cell culture. Furthermore, this culturing technique also provides an appropriate system for gene delivery to retinal cells and will serve to simulate gene therapeutic approaches prior to difficult and time-consuming in vivo experiments.  相似文献   
994.
The human and monetary costs of chronic hepatitis C and the complications arising from this disease emphasize the urgency to find a treatment for Hepatitis C Virus (HCV) infected patients. The current standard of treatment for patients chronically infected with HCV is combination therapy with pegylated interferon plus ribavirin. Recently, viral enzymes have become the target of efforts to develop small molecule inhibitors interfering with the essential steps in the life cycle of the virus. Amongst these enzymes the HCV-encoded NS5B RNA-dependent RNA polymerase (NS5B RdRp) is essential for viral replication and has been recognized as a prime target for therapeutic intervention. Several distinct classes of inhibitors of NS5B RdRp have been disclosed in the literature, including active site inhibitors such as nucleosides and pyrophosphate mimetics, as well as non-nucleoside inhibitors. The latter, based on the success of allosteric inhibitors in the treatment of HIV infection, have been developed into compounds which show activity in the subgenomic cell-culture assay of HCV replication. This review provides an account of the recent developments in this field.  相似文献   
995.
BACKGROUND: Ovarian small cell carcinoma of the hypercalcemic type is a rare neoplasm that is associated with a poor prognosis. The objective of the current study was to investigate the clinicopathologic features of this tumor and to develop preliminary diagnostic and therapeutic guidelines. METHODS: Between 1994 and 2005, 11 girls (ages 9-22 years) who were registered on the German Maligne Keimzelltumoren studies and the Kiel Pediatric Tumor Registry were analyzed. Prior to histopathologic review, 8 patients had been misdiagnosed with either germ cell tumor or juvenile granulosa cell tumor. RESULTS: According to the International Federation of Gynecologic Oncology, 4 patients had Stage IA disease, 3 patients had Stage IC disease, and 4 patients had Stage III disease. After resection, 4 patients were followed without additional therapy, and all 4 patients developed recurrent disease after 3 to 11 months. Seven patients received adjuvant chemotherapy during first-line treatment. One patient with Stage III disease received additional regional deep hyperthermia. During first-line treatment, high-dose chemotherapy was received by 4 patients who achieved a complete response (CR) after conventional chemotherapy. All 4 of those patients remained in CR for 7 to 73 months, whereas the other 3 patients developed recurrent disease. Salvage treatment after recurrence or tumor progression consisted of surgery and chemotherapy. One patient received high-dose chemotherapy in 2nd CR and remained in 2nd CR. In total, 5 patients remained alive with no evidence of disease. CONCLUSIONS: Patients with ovarian small cell carcinoma of the hypercalcemic type require multiagent chemotherapy during first-line treatment. High-dose chemotherapy may be used to consolidate the therapeutic success.  相似文献   
996.
BACKGROUND: Because of the considerable heterogeneity in breast carcinoma with noninflammatory skin involvement (T4b/Stage IIIB), a revision was proposed of the TNM staging system that would classify these tumors exclusively based on their tumor size and lymph node status. In the current study, the authors evaluated how implementation of this proposal will affect Stage III noninflammatory breast cancer. METHODS: Two hundred seven patients who were classified with noninflammatory Stage III breast cancer were treated consecutively between 1990 and 1999 at the University Hospital Basel, Switzerland. To assess the extent of T4b/Stage IIIB tumors independent of the clinicopathologic feature of skin involvement, the reclassification was undertaken. RESULTS: Of 68 patients who had nonmetastatic T4b breast cancer, 37 patients (54.4%) had a tumor extent in accordance with Stage I/II and had improved disease-specific survival (DSS) compared with patients who had Stage III breast cancer (P = .008). Excluding those patients from Stage III led to a 17.9% reduction of the number of patients in this group (n = 170 patients). The 10-year DSS declined from 48.5% to 42.9%. CONCLUSIONS: Considerable numbers of patients who are classified with noninflammatory Stage IIIB breast cancer show only a limited disease extent. Through a revision of the T4 category, these low-risk patients were excluded from the highest nonmetastatic TNM stage, and overstaging could be avoided. This procedure decreased the degree of heterogeneity of the entire Stage III group and may result in a more precise assessment of this disease entity.  相似文献   
997.
Objectives Improvements in the life expectancy of women with breast cancer raise important questions how to improve quality of life (QoL) for women sustaining complications and side effects of cancer treatment. The presented study examined the prevalence of arm morbidity in a cohort of primary breast cancer patients over time as a result of the extent of axillary lymph node dissection. Of particular interest is the question of using a recognized QoL assessment instrument at defined assessment points as an endpoint criteria of oncological treatment.Methods A prospective, population-based, longitudinal cohort study of patients with primary breast cancer was performed (n = 389). QoL data (EORTC QLQ C30 + BR23) and clinical data were assessed at designated time points. Primary endpoint of this analysis was patient reported arm morbidity assessed with the three-idem scale in the BR 23 (swelling, moving, pain).Results 20% of the patients evidenced considerable impairments in arm functioning. Arm morbidity was significantly related to the number of lymph nodes dissected (P < 0.002 entire cohort, P < 0.001 lymph node negatives) and was independent of age, stage of the disease, kind of breast surgery and radiation treatment. Early impairments in arm functioning (below 50 score values) assessed within 6 months after axillary surgery was a good predictor for late arm morbidity at 12 months RR 11.5 (CI 95% 4.7–28.4), 24 months RR 6.0 (CI95% 2.8–13.3) and 36 months RR 3.8 (CI 95% 1.8–7.9).Conclusions Arm morbidity after axillary surgery is a severe and chronic condition affecting many breast cancer patients. The recognized QoL assessment instrument depict patients with severe impairments in arm functioning after axillary lymph node dissection and predict late arm morbidity. To increase patients’ quality of life it thus may serve as a valid assessment tool for screening, allowing early referral for treatment and monitoring.  相似文献   
998.
Purpose The aim of this study was to evaluate health-related quality of life (HRQOL) in breast cancer patients across countries, and to cross-culturally examine the impact of psychosocial factors on HRQOL.Patients and methods A total of 413 women with breast cancer from Germany (n=195), Japan (n=112), and Korea (n=106) completed a survey assessing HRQOL and HRQOL-related factors. HRQOL was measured using the Short-Form Health Survey (SF-8). Measures of psychological distress (Hospital Anxiety and Depression Scale and Impact of Event Scale-Revised), coping (Dealing with Illness Inventory-German Revised), and social support (Illness-Specific Social Support Scale-German Revised) were included.Results The effect of the factor country on physical QOL was seen to be significant, but small (P=0.049, ES=0.018). The scales of General Health (P=0.023), Vitality (P=0.004), and Role Emotional (P=0.003) differed across countries, with the South Korean patients having lower scores compared to the German and Japanese patients. The nature of the impact of psychosocial factors on HRQOL did not differ greatly across countries except with regard to avoidance, however, the degree to which these factors influence HRQOL did differ greatly. Overall, depression, depressive coping, and problematic support showed a strong detrimental effect on the HRQOL of breast cancer patients.Conclusions Results from this study suggest that strategies which target an improvement of HRQOL in cancer patients should also consider the patients’ cultural and healthcare system contexts. Interventions are needed to improve detrimental psychosocial factors.  相似文献   
999.
The objective of this study was to explore the protein expression pattern in normal endometrial mucosa (n = 5) and endometrial carcinoma (n = 15) of low (diploid) and high (aneuploid) malignancy potential by two-dimensional gel electrophoresis (2-DE). The specimens were evaluated for histopathologic subtype, stage and grade in relation to DNA ploidy. A match-set consisting of five samples from normal endometrium, eight diploid and seven aneuploid tumours was created. All the diploid and three of the aneuploid tumours were of endometrioid subtype, while the remaining four were of uterine seropapillary type. There were 192 protein spots differentiating diploid tumours from normal endometrium and 238 protein spots were separating aneuploid tumours from normal endometrium (p < 0.01). A cluster analysis based on 52 significantly deviating protein spots within the groups showed clustering and separation of the normal endometrium, diploid and aneuploid tumours. In conclusion this study showed significant differences in protein expression between normal endometrium and endometrial carcinoma as well as between endometrial carcinoma of low and high malignancy potential. In future studies these results may provide useful in finding new sensitive prognostic markers for endometrial cancer.  相似文献   
1000.
The increased consumption of fruits and vegetables is associated with reduced cardiovascular disease. The molecular basis of this health effect is not fully understood, yet dietary flavonoids are thought to play an important role. Genetic engineering has enabled us to overexpress specific flavonoids (flavones and flavonols) in tomato fruit. Human C-reactive protein transgenic (CRPtg) mice express markers of cardiovascular risk that allow us to study of the putative health effects of wild-type tomato (wtTom) and flavonoid-enriched tomato (flTom). In this study, we analyzed whether consumption of wtTom, at a dose achievable with a human diet, has beneficial effects on cardiovascular risk markers and whether flTom may enhance such effects. CRPtg mice were fed a diet containing 4 g/kg wtTom, flTom peel, vehicle, or 1 g/kg fenofibrate, which reportedly reduces cardiovascular risk, for 7 wk. Markers of general health (bodyweight, food intake, and plasma alanine aminotransferase activities) and of cardiovascular risk (plasma CRP, fibrinogen, E-selectin, and cholesterol levels) were analyzed. All groups had comparable food intakes and body-weight gains. Plasma alanine aminotransferase activities increased significantly in vehicle and fenofibrate-treated mice. Compared with baseline, wtTom and flTom significantly reduced basal human CRP concentrations by 43 and 56%, respectively. The CRP-lowering effect of flTom significantly exceeded that of wtTom. The effects of flTom on CRP were reversed within a 2-wk washout period. WtTom and flTom did not affect fibrinogen, but comparably repressed E-selectin expression and upregulated HDL cholesterol. Tomato peel consumption improved cardiovascular risk factors in CRPtg mice, a beneficial effect that was further enhanced by enrichment of the flavonoid content.  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