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   32576篇
  免费   1947篇
  国内免费   100篇
耳鼻咽喉   253篇
儿科学   1111篇
妇产科学   935篇
基础医学   3675篇
口腔科学   391篇
临床医学   5892篇
内科学   5461篇
皮肤病学   358篇
神经病学   3162篇
特种医学   614篇
外国民族医学   1篇
外科学   3260篇
综合类   296篇
现状与发展   1篇
一般理论   51篇
预防医学   4514篇
眼科学   464篇
药学   1923篇
中国医学   41篇
肿瘤学   2220篇
  2023年   194篇
  2022年   297篇
  2021年   646篇
  2020年   445篇
  2019年   682篇
  2018年   854篇
  2017年   591篇
  2016年   669篇
  2015年   718篇
  2014年   1053篇
  2013年   1662篇
  2012年   2367篇
  2011年   2476篇
  2010年   1317篇
  2009年   1153篇
  2008年   2235篇
  2007年   2434篇
  2006年   2300篇
  2005年   2234篇
  2004年   2059篇
  2003年   1983篇
  2002年   1899篇
  2001年   226篇
  2000年   193篇
  1999年   289篇
  1998年   376篇
  1997年   310篇
  1996年   247篇
  1995年   276篇
  1994年   215篇
  1993年   214篇
  1992年   137篇
  1991年   141篇
  1990年   138篇
  1989年   111篇
  1988年   103篇
  1987年   95篇
  1986年   99篇
  1985年   109篇
  1984年   127篇
  1983年   126篇
  1982年   144篇
  1981年   139篇
  1980年   118篇
  1979年   57篇
  1978年   71篇
  1977年   61篇
  1976年   49篇
  1975年   37篇
  1974年   42篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
81.
This article reviews the pertinent anatomy of each body system involved in the assessment of the head and neck (including the eyes, ears, nose, and throat) and describes the basic elements of the comprehensive health assessment. Frequently encountered chief complaints are discussed. Aspects of the health assessment that will assist the primary care provider in making a differential diagnosis and determining the need for referral are presented. This article is the first of two articles on this topic; the subsequent article will address primary care management of common conditions of the head and neck.  相似文献   
82.
A 25–year-old woman was admitted to the hospital because of rising trough cyclosporine concentrations thought to be due to self-administration of 4 times the normal dosage of the drug for 8 days. Her symptoms included colicky central abdominal pains and urinary retention; her serum creatinine concentrations were elevated. Whole blood cyclosporine and metabolite concentrations were measured by high-performance liquid chromatography and monoclonal radioimmunoassays. The highest reported trough cyclosporine concentration was 5877 ng/ml, and AM1 (M17) concentration was 3425 ng/ml. A cyclosporine half-life of 91 hours was calculated. Nine days after the agent was discontinued the patient's serum creatinine concentration had returned to normal and her symptoms resolved. Due to the availability of three sizes of cyclosporine capsules, and the need for frequent dosage changes, continued vigilance is necessary to ensure that patients understand their drug regimen.  相似文献   
83.
In December 1990, an empirical study assessing hospital ethics committee (HEC) success was completed. Success was measured in terms of the number of interventions undertaken by the committees in four functional areas: education, guidelines development, prospective and retrospective case review. Some commonly quoted success determinants, such as multidisciplinarity, physician chairpersons, and a high institutional status of the chairperson were found not to foster success; the latter two, actually decreased committee success.  相似文献   
84.
The role of selected prior medical conditions in the etiology of hematopoietic malignancies was examined in a case-control study of members of two regional branches of the Kaiser Permanente Medical Care Program (USA). Past history of chronic infectious, autoimmune, allergic, and musculoskeletal disorders was abstracted from medical records for leukemia (n = 299), non-Hodgkin's lymphoma (NHL, n = 100), and multiple myeloma (n = 175) cases and matched controls (n = 787). Little difference was found between cases and controls for most of the chronic conditions evaluated, including sinusitis, carbuncles, urinary tract infections, pelvic infections, herpes zoster, asthma, rheumatoid arthritis, psoriasis, bursitis, and gout. Only three statistically significant elevated risks were found, i.e., with combined disc disease myeloma among patients with prior eczema and disk and other musculoskeletal conditions, and NHL following tuberculosis. Only two of these associations showed consistent patterns by sex and geographic region (myeloma with eczema and with musculoskeletal conditions). While prior history of eczema and musculoskeletal conditions may slightly increase risk of myeloma, this study provided little if any support for an association of chronic infectious, autoimmune, allergic, and musculoskeletal conditions with subsequent occurrence of the leukemias or NHL. Additionally, these data did not support a role for chronic antigenic stimulation, as defined in previous epidemiologic studies, in the etiology of hematopoietic malignancies.Ms Doody and Drs Linet, Pottern, Boice, and Fraumeni are with the Epidemiology and Biostatistics Program, National Cancer Institute. Dr Glass is with the Kaiser Permanente Medical Care Program, Northwest Region, Portland, Oregon, USA. Dr Friedman is with the Kaiser Permanente Medical Care Program, Northern California Region, Oakland, California, USA. Address correspondence to Ms Doody, Radiation Epidemiology Branch, National Cancer Institute, Executive Plaza North, Room 408, Bethesda, MD 20892, USA. This research was supported in part by National Cancer Institute contracts NO1-CP-01047, NO1-CP-01054, NO1-CP-11009, NO1-CP-11037, NO1-CP-31035, and NO1-CP-61006.  相似文献   
85.
86.
Younger women smoke at disproportionately higher rates than other women and their smoking has a major impact on the health of their young children. To address this problem, a smoking cessation intervention combining minimal advice and assistance from a community health nurse and a tailored self-help guide was developed for low-income women with young children. The program evaluation results reported here were gathered from women using publicly funded pediatric services in four agencies with 32 clinic sites in central and eastern Pennsylvania. Unlike volunteers in formal cessation programs, the women varied widely in their readiness to quit smoking. Follow-up data were obtained from 1,230 female smokers, aged 18 to 39, after receiving brief, individualized smoking cessation advice and encouragement to read the self-help guide. One year later, 12.5 percent reported quitting smoking, and 20.2 percent reported having made a serious quit attempt that lasted at least 7 days. These results suggest that, even among smokers with low socioeconomic status and wide variation in their readiness to quit, minimal intervention programs requiring modest resources can promote cessation.This work was funded under contracts from the Cancer Control Program, Pennsylvania Department of Health (SPC-883141 and SPC-979425). The Quitting Times STOP IT quit smoking protocol was adapted from the Smoking Cessation Project, Maternal and Child Health, Massachusetts Department of Public Health. The authors also wish to express appreciation to the staff of the Division of Population Science, Fox Chase Cancer Center for their contributions to this project and especially those of Chris Jepson, Eunice King, C. Tracy Orleans, and Marjorie Utt.  相似文献   
87.
88.
The efficacy of fractionated out-patient radioiodine therapy in 38 patients with compressive symptoms due to long-standing large multinodular goitres was assessed. The diagnosis was established by clinical assessment in addition to technetium-99m pertechnetate thyroid scan or computed tomography scan of the thyroid and mediastinum. Oral iodine-131 therapy was administered as a 2.22 GBq (60 mCi) cumulative dose over 4 months (555 MBq per month). All patients were monitored with serum thyroid-stimulating hormone and free thyroxine (± free tri-iodothyronine) assays before the treatment and after each dose fraction. Clinical and biochemical follow-up was performed on all patients and ranged from 6 to 45 months after therapy. The patients consisted of 35 female and three male patients with a median age of 59 years (range 37–87 years). Prior to treatment 20 patients were biochemically hyperthyroid and 18 were euthyroid. Overall, 71% of patients reported a subjective improvement in compressive symptoms and 29% reported no change. Clinically assessed reduction in goitre size occurred in 92% of patients while there was no change in 8%. At 3 months of follow-up, 31% of patients had become hypothyroid and at 18 months 66% were hypothyroid. Seven hyperthyroid patients (35%) became euthyroid and 13 hyperthyroid patients (65%) became hypothyroid. Three patients who became hypothyroid experienced neck soreness (transient in one patient, persistent in two patients). There were no differences in outcome between patients who were hyperthyroid and those who were euthyroid prior to treatment. Fractionated out-patient radioiodine therapy showed excellent short- and medium-term safety, was very well tolerated and offered a satisfactory alternative treatment to surgery. Received 23 May and in revised form 11 August 1997  相似文献   
89.
The chemical characteristics of 10 neoplastic and 11 infectious brain masses were studied by in vivo 1H magnetic resonance spectroscopy. In tumors, peak height ratios of n-acetyl-L-aspartate to choline were decreased compared to those in normal brain tissue and infectious masses (p < 0.02), but the ratios in normal brains and those with infections did not differ. N-acetyl-L-aspartate—to-creatine/phosphocreatine ratios were significantly lower in infectious masses and tumors compared to normal brain tissue (p = 0.003). However, in progressive multifocal leukoencephalopathy, N-acetyl-L-aspartate appeared relatively unchanged. Lactate was greater than choline in 9 of 11 brains with infection, 0 of 14 control brains, and 1 of 10 tumors. Lactate-to-choline ratios were significantly elevated in infectious masses compared with tumors (p < 0.01). 1H magnetic resonance spectroscopy is promising for the noninvasive diagnosis of focal brain masses.  相似文献   
90.
Our group has previously reported significant changes in the incorporation of precursors into glycerophospholipids, particularly phosphatidylserine, in polymorphonuclear cells obtained from the peripheral blood of cluster headache patients, when compared with controls. The potential of these results led to further work using both the previous methodology and a modified isolation technique to obtain polymorphonuclear cells in as pure a state as possible. Neither the new results obtained using the original technique, nor the results with high purity polymorphonuclear cells from controls and cluster headache patients, confirm the marked changes in precursor uptake into glycerophospholipids originally reported.  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