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   22744篇
  免费   1628篇
  国内免费   89篇
耳鼻咽喉   153篇
儿科学   770篇
妇产科学   523篇
基础医学   3304篇
口腔科学   328篇
临床医学   2776篇
内科学   4999篇
皮肤病学   480篇
神经病学   2395篇
特种医学   386篇
外科学   2006篇
综合类   128篇
一般理论   28篇
预防医学   2523篇
眼科学   246篇
药学   1530篇
中国医学   43篇
肿瘤学   1843篇
  2024年   20篇
  2023年   215篇
  2022年   387篇
  2021年   763篇
  2020年   509篇
  2019年   760篇
  2018年   783篇
  2017年   576篇
  2016年   651篇
  2015年   713篇
  2014年   909篇
  2013年   1189篇
  2012年   1937篇
  2011年   1943篇
  2010年   1036篇
  2009年   872篇
  2008年   1512篇
  2007年   1562篇
  2006年   1539篇
  2005年   1424篇
  2004年   1313篇
  2003年   1163篇
  2002年   1018篇
  2001年   137篇
  2000年   86篇
  1999年   148篇
  1998年   191篇
  1997年   136篇
  1996年   133篇
  1995年   121篇
  1994年   82篇
  1993年   86篇
  1992年   43篇
  1991年   43篇
  1990年   41篇
  1989年   48篇
  1988年   34篇
  1987年   25篇
  1986年   31篇
  1985年   28篇
  1984年   39篇
  1983年   26篇
  1982年   25篇
  1981年   26篇
  1980年   19篇
  1979年   12篇
  1978年   14篇
  1976年   16篇
  1973年   12篇
  1971年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Objective: To assess the risk of neoplastic development among persons exposed to scalp irradiation. Study Design: Historical cohort study initially; prospective follow-up subsequently. Method: Two control groups—population and siblings—matched for age, sex, ethnic origin, and year of immigration. Follow-up from time of irradiation (1950s) until the end of 1991. Linkage with nationwide cancer registry. Results: A 4.5–fold incidence of cancer (P < .01) and a 2.6–fold increase of benign tumors were noted. The mean length of latency period until tumor development was 11 years for malignant tumors and 21.5 years for benign. A clear dose response effect for both cancer and benign tumors was demonstrated. Conclusions: The study confirms the role of radiation in salivary gland carcinogenesis. It indicates a need for better awareness, a comprehensive examination, and long-term follow-up of patients who have been subjected to head and neck radiation.  相似文献   
102.
Improving the quality of care for patients with chronic illness has become a high priority. Implementing training programs in disease management (DM) so the next generation of physicians can manage chronic illness more effectively is challenging. Residency training programs have no specific mandate to implement DM training. Additional barriers at the training facility include: 1) lack of a population-based perspective for service delivery; 2) weak support for self-management of illness; 3) incomplete implementation due to physician resistance or inertia; and 4) few incentives to change practices and behaviors. In order to overcome these barriers, training programs must take the initiative to implement DM training that addresses each of these issues. We report the implementation of a chronic illness management curriculum based on the Improving Chronic Illness Care (ICIC) Model. Features of this process included both patient care and learner objectives. These were: development of a multidisciplinary diabetes DM team; development of a patient registry; development of diabetes teaching clinics in the family practice center (nutrition, general management classes, and one-on-one teaching); development of a group visit model; and training the residents in the elements of the ICIC Model, ie, the community, the health system, self-management support, delivery system design, decision support, and clinical information systems. Barriers to implementing these curricular changes were: the development of a patient registry; buy-in from faculty, residents, clinic leadership, staff, and patients for the chronic care model; the ability to bill for services and maintain clinical productivity; and support from the health system key stakeholders for sustainability. Unique features of each training site will dictate differences in emphasis and structure; however, the core principles of the ICIC Model in enhancing self-management may be generalized to all sites.  相似文献   
103.
104.
PURPOSE: Point mutations within the ABL kinase domain of the BCR-ABL gene have been associated with clinical resistance to imatinib mesylate in chronic myeloid leukemia (CML) patients. To shed further light on the frequency, distribution, and prognostic significance of ABL mutations, we retrospectively analyzed a homogeneous cohort of late chronic phase CML patients who showed primary cytogenetic resistance to imatinib. PATIENTS AND METHODS: Using denaturing high-performance liquid chromatography (D-HPLC) and sequencing, we screened for ABL mutations in a total of 178 bone marrow and/or peripheral blood samples from 40 late chronic phase CML patients homogeneously treated with imatinib 400 mg/d, who did not reach a major cytogenetic response at 12 months. RESULTS: Mutations were found in 19 of 40 patients (48%). Mutations were already detectable by D-HPLC at a median of 3 months from the onset of therapy. The presence of a missense mutation was significantly associated with a greater likelihood of subsequent progression to accelerated phase/blast crisis (P = .0002) and shorter survival (P = .001). Patients carrying mutations falling within the P-loop seemed to have a particularly poor outcome in terms of time to progression (P = .032) and survival (P = .045). CONCLUSION: Our results show that, irrespective of the hematologic response, monitoring for emerging mutations in the first months of therapy may play a role in detecting patients with worse prognosis, for whom a revision of the therapeutic strategy should be considered.  相似文献   
105.
Rats were exposed to three levels of bromobenzene, sampled at 6, 24, and 48 h, and liver gene expression profiles were determined to identify dose and time-related changes. Expression of many genes changed transiently, and dependent on the dose. Few changes were identified after 6 h, but many genes were differentially expressed after 24 h, while after 48 h, only the high dose elicited large effects. Differentially expressed genes were involved in drug metabolism (upregulated GSTs, mEH, NQO1, Mrps, downregulated CYPs, sulfotransferases), oxidative stress (induced HO-1, peroxiredoxin, ferritin), GSH depletion (induced GCS-l, GSTA, GSTM) the acute phase response, and in processes like cholesterol, fatty acid and protein metabolism, and intracellular signaling. Trancriptional regulation via the electrophile and sterol response elements seemed to mediate part of the response to bromobenzene. Recovery of the liver was suggested in response to BB by the altered expression of genes involved in protein synthesis and cytoskeleton rearrangement. Furthermore, after 48 h, rats in the mid dose group showed no toxicity, and gene expression patterns resembled the normal situation. For certain genes (e.g., CYP4A, metallothioneins), intraday variation in expression levels was found, regardless of the treatment. Selected cDNA microarray measurements were confirmed using the specific and sensitive branched DNA signal amplification assay.  相似文献   
106.
107.
Bartonella henselae, the causative agent of cat‐scratch disease, has been recognized to be responsible for a broad range of clinical syndromes. We report the case of a patient with disseminated B. henselae infection mimicking Langerhans cell histiocytosis at presentation and its successful management with neurosurgery, prolonged antibacterial therapy, and observation.  相似文献   
108.
Recent studies in mouse models of cancer have shown that exercise improves tumor vascular function, thereby improving chemotherapy delivery and efficacy. However, the mechanisms underlying this improvement remain unclear and the effect of exercise on Ewing sarcoma (ES), a pediatric bone and soft tissue cancer, is unknown. The effect of exercise on tumor vascular hyperpermeability, which inversely correlates with drug delivery to the tumor, has also not been evaluated. We hypothesized that exercise improves chemotherapy efficacy by enhancing its delivery through improving tumor vascular permeability. We treated ES‐bearing mice with doxorubicin with or without moderate treadmill exercise. Exercise did not significantly alter ES tumor vessel morphology. However, compared to control mice, tumors of exercised mice had significantly reduced hyperpermeability, significantly decreased hypoxia, and higher doxorubicin penetration. Compared to doxorubicin alone, doxorubicin plus exercise inhibited tumor growth more efficiently. We evaluated endothelial cell sphingosine‐1‐phosphate receptors 1 and 2 (S1PR1 and S1PR2) as potential mediators of the improved vascular permeability and increased function afforded by exercise. Relative to tumors from control mice, vessels in tumors from exercised mice had increased S1PR1 and decreased S1PR2 expression. Our results support a model in which exercise remodels ES vasculature to reduce vessel hyperpermeability, potentially via modulation of S1PR1 and S1PR2, thereby improving doxorubicin delivery and inhibiting tumor growth more than doxorubicin alone does. Our data suggest moderate aerobic exercise should be tested in clinical trials as a potentially useful adjuvant to standard chemotherapy for patients with ES.  相似文献   
109.
110.
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