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   4356篇
  免费   199篇
  国内免费   14篇
耳鼻咽喉   31篇
儿科学   162篇
妇产科学   109篇
基础医学   887篇
口腔科学   72篇
临床医学   341篇
内科学   983篇
皮肤病学   48篇
神经病学   264篇
特种医学   303篇
外科学   493篇
综合类   62篇
一般理论   2篇
预防医学   220篇
眼科学   72篇
药学   250篇
中国医学   11篇
肿瘤学   259篇
  2021年   44篇
  2020年   40篇
  2019年   43篇
  2018年   49篇
  2017年   39篇
  2016年   36篇
  2015年   62篇
  2014年   81篇
  2013年   120篇
  2012年   176篇
  2011年   173篇
  2010年   105篇
  2009年   123篇
  2008年   185篇
  2007年   171篇
  2006年   175篇
  2005年   177篇
  2004年   144篇
  2003年   140篇
  2002年   173篇
  2001年   152篇
  2000年   140篇
  1999年   105篇
  1998年   59篇
  1997年   51篇
  1996年   55篇
  1995年   40篇
  1994年   44篇
  1993年   44篇
  1992年   109篇
  1991年   83篇
  1990年   83篇
  1989年   83篇
  1988年   78篇
  1987年   73篇
  1986年   61篇
  1985年   62篇
  1984年   34篇
  1983年   35篇
  1979年   61篇
  1978年   38篇
  1977年   38篇
  1974年   32篇
  1973年   42篇
  1972年   47篇
  1968年   31篇
  1935年   32篇
  1934年   33篇
  1933年   29篇
  1930年   30篇
排序方式: 共有4569条查询结果,搜索用时 31 毫秒
71.
72.
PURPOSE: Investigation of high-dose chemotherapy (HD-CT) followed by autologous hematopoietic stem-cell support compared with standard-dose chemotherapy (SD-CT) as adjuvant treatment in patients with primary breast cancer and 10 or more positive axillary lymph nodes. PATIENTS AND METHODS: Between November 1993 and September 2000, 307 patients were randomized to receive (following four cycles of epirubicin 90 mg/m(2) and cyclophosphamide 600 mg/m(2), intravenously every 21 days) either HD-CT of cyclophosphamide 1500 mg/m(2), thiotepa 150 mg/m(2), and mitoxantrone 10 mg/m(2), intravenously for 4 consecutive days followed by stem-cell support; or SD-CT in three cycles of cyclophosphamide 500 mg/m(2), methotrexate 40 mg/m(2), and fluorouracil 600 mg/m(2) intravenously on days 1 and 8, every 28 days. The primary end point was event-free survival. RESULTS: After a median follow-up of 3.8 years, 144 events with respect to event-free survival have been observed (HD-CT: 63 events; SD-CT: 81 events). The first event of failure (HD-CT v SD-CT) was an isolated locoregional recurrence (nine v 11), a distant failure (52 v 68), and death without recurrence (two v two). The estimated relative risk of HD-CT versus SD-CT was 0.75 (95% CI, 0.54 to 1.06; P =.095). Overall survival showed no difference (HD-CT: 40 deaths; SD-CT: 49 deaths). CONCLUSION: There was a trend in favor of HD-CT with respect to event-free survival, but without statistical significance. Further follow-up and a meta-analysis of all randomized studies will reveal the effect of HD-CT as compared with SD-CT as adjuvant treatment in high-risk primary breast cancer.  相似文献   
73.
Restoration of blood flow to reperfuse ischemic but not infarcted areas of the brain (ischemic penumbra) and the removal of an ongoing embolic source are the therapeutic aims of emergency and urgent carotid endarterectomy (CEA), both in patients with an acute or progressive ischemic stroke and in patients in the early period after a carotid-related stroke. Based on poor results in the 60ies and 70ies, many centers traditionally perform CEA four to six weeks after a carotid-related stroke at the earliest interval. Since natural history is associated with a high risk of an disabling and/or recurrent stroke in several subgroups of patients, some reports were able to show that urgent and emergency CEA could be worthwhile in well-selected patients.  相似文献   
74.
OBJECTIVE: To review the evidence regarding the effects of interventions to improve hospital design and construction on the occurrence of nosocomial infections. METHODS: Systematic review of experimental and non-experimental, architectural intervention studies in intensive care units (ICUs), surgical departments, isolation units, and hospitals in general. The studies dated from 1975, and were in English, French, German, Italian, and Spanish. Regardless of format, the studies were identified through seven medical databases, reference lists, and expert consultation. RESULTS: One hundred seventy-eight scientific articles were identified; however, none of these described a meta-analysis, systematic review, or randomized, controlled trial. Most of the articles were categorized at the lowest level of evidence (expert judgment or consensus statements). Only 17 described completed concurrent or historical cohort studies matching the inclusion criteria (ICUs, 9; surgical departments, 4; isolation units, 2; hospitals in general, 2). The interventions generally included a move to other premises or renovation. However, in many studies, the staff-to-patient ratio was also improved. Some studies showed lower infection rates after intervention, but this finding cannot be generalized because of confounding and frequently small study populations. CONCLUSIONS: The lack of stringent evidence linking hospital design and construction with the prevention of nosocomial infection is partly attributable to the multifactorial nature of these infections, and some improvement will be seen if basic conditions such as the availability of sufficient space, isolation capacity, and facilities for handwashing are met. However, to our knowledge, other factors, especially the improper hand hygiene of medical staff, have greater impact.  相似文献   
75.
It has been the subject of numerous debates recently whether children who grew up without fathers suffer more than others under the long-term consequences of their fatherless childhood. In 1994 we conducted a large-scale population-based investigation over a hundred subjects who had grown up without father to establish standardized norms for various psychometric questionnaires that were also relevant to this issue. This allows us to contribute to the discussion with some concrete data, which correspond without exception with the dominant trend of other research results. Whereas there was evidence to support the view that some children of fatherless families do indeed suffer from increased emotional disturbance in later life, there were also indications that others even profited emotionally from their fatherless childhood. In the area of bodily complaints the results were confounded to a high degree with gender differences, showing that women are more frequently negatively affected, and men more positively.  相似文献   
76.
In this article we will describe the evaluation of Antonovsky's 29-items Sense of Coherence Scale (SOC-29) in a large community sample (n = 2.005) of the German population and the development of the Leipzig Short Scale (SOC-L9), which consists of only 9 items. The SOC-29 has a high internal consistency (alpha = 0.92), however, the SOC-subscales (comprehensibility, manageability, meaningfulness) were correlated with each other. A principal component factor analysis did not identify the 3-factor structure of the SOC-Scale. It appears that the best solution consists of one global factor. The newly developed SOC-L9, conceptualized as an unidimensional scale, is a reliable and valid instrument, which allows to assess the SOC economically. In our study the Sense of Coherence depended on age and gender. Women and older people reported a lower SOC. Furthermore we found significant associations between SOC and different subjective health measures. A high SOC was associated with both a lower extent of subjective body complaints and somatoform symptoms and with minor health-related problems in daily living.  相似文献   
77.
Angiogenesis in ischemic human myocardium: clinical results after 3 years   总被引:9,自引:0,他引:9  
BACKGROUND: Using the human fibroblast growth factor we could already demonstrate the induction of neoangiogenesis in the ischemic human myocardium. METHODS: Forty patients, who were undergoing elective coronary artery bypass grafting were randomly selected and allotted either to a treatment or a control group. In 20 patients (study group) fibroblast growth factor was injected directly into the myocardium, close to the left anterior descending coronary artery. The control group comprised 20 patients who had been injected with heat denatured fibroblast growth factor. The 3-year follow-up consisted of a clinical examination, echocardiography, and selective imaging of the internal mammary artery bypass using angiography. RESULTS: As with the early results, a dense new capillary network could be demonstrated angiographically in the region where the factor had been injected. Echocardiography showed an increase in the left ventricular ejection fraction in the study group. We also found a more pronounced improvement in the clinical appearance of the patients with fibroblast growth factor. CONCLUSIONS: Fibroblast growth factor, in addition to operative myocardial revascularization, may be the appropriate treatment for patients with peripheral stenosis or diffuse coronary arteriosclerosis. It is necessary to confirm these results in further studies on a larger group of patients.  相似文献   
78.
79.
Esophageal intramural pseudodiverticulosis (EIP) is a rare disorder of unknown etiology. On histopathology, it is characterized by dilation of the submucosal esophageal glands. The main presenting symptom is dysphagia to solid foods. Most patients diagnosed with EIP also have a history of diabetes mellitus, gastroesophageal reflux disease, esophageal candidiasis, or chronic alcohol and nicotine abuse. Yet, the exact pathophysiologic mechanism still remains unclear. The most frequent complication, occurring in 80 % of the patients, is esophageal stricture. The mainstay of therapy is directed towards symptom relief with administration of proton pump inhibitors (PPIs) combined with antifungals and/or endoscopic dilations, if necessary. We report a case of a 69-year-old man who presented with a 9-month history of progressive dysphagia and a 25 kg-weight loss, with typical endoscopic findings of EIP and successful response to medical therapy with oral antifungals alone.  相似文献   
80.
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