全文获取类型
收费全文 | 14986篇 |
免费 | 1842篇 |
国内免费 | 159篇 |
专业分类
耳鼻咽喉 | 46篇 |
儿科学 | 581篇 |
妇产科学 | 845篇 |
基础医学 | 634篇 |
口腔科学 | 74篇 |
临床医学 | 1174篇 |
内科学 | 4770篇 |
皮肤病学 | 59篇 |
神经病学 | 732篇 |
特种医学 | 96篇 |
外国民族医学 | 1篇 |
外科学 | 2249篇 |
综合类 | 803篇 |
一般理论 | 1篇 |
预防医学 | 2918篇 |
眼科学 | 28篇 |
药学 | 466篇 |
中国医学 | 30篇 |
肿瘤学 | 1480篇 |
出版年
2024年 | 32篇 |
2023年 | 447篇 |
2022年 | 670篇 |
2021年 | 1081篇 |
2020年 | 823篇 |
2019年 | 873篇 |
2018年 | 805篇 |
2017年 | 685篇 |
2016年 | 710篇 |
2015年 | 676篇 |
2014年 | 975篇 |
2013年 | 1256篇 |
2012年 | 631篇 |
2011年 | 713篇 |
2010年 | 526篇 |
2009年 | 595篇 |
2008年 | 632篇 |
2007年 | 607篇 |
2006年 | 577篇 |
2005年 | 444篇 |
2004年 | 423篇 |
2003年 | 342篇 |
2002年 | 289篇 |
2001年 | 247篇 |
2000年 | 182篇 |
1999年 | 165篇 |
1998年 | 165篇 |
1997年 | 156篇 |
1996年 | 142篇 |
1995年 | 125篇 |
1994年 | 117篇 |
1993年 | 112篇 |
1992年 | 99篇 |
1991年 | 77篇 |
1990年 | 72篇 |
1989年 | 60篇 |
1988年 | 72篇 |
1987年 | 55篇 |
1986年 | 71篇 |
1985年 | 64篇 |
1984年 | 50篇 |
1983年 | 32篇 |
1982年 | 27篇 |
1981年 | 17篇 |
1980年 | 9篇 |
1979年 | 18篇 |
1978年 | 10篇 |
1976年 | 7篇 |
1974年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Proportionate mortality of crop and livestock farmers in the United States, 1984-1993 总被引:2,自引:0,他引:2
Lee E Burnett CA Lalich N Cameron LL Sestito JP 《American journal of industrial medicine》2002,42(5):410-420
BACKGROUND: Livestock farmers are more likely to be exposed to a variety of different farming hazards than crop farmers. An analysis of occupation and industry-coded U.S. death certificate data from 26 states for the years 1984-1993 was conducted to evaluate mortality patterns among crop and livestock farmers. METHODS: Cause-specific proportionate mortality ratios (PMRs) were calculated using a National Institute for Occupational Safety and Health (NIOSH) computer program designed to calculate sex and race specific PMRs for occupations and industries in population-based data. RESULTS: Among white male (WM) livestock farmers, there was a significantly higher mortality from cancer of the pancreas, prostate and brain, non-Hodgkin's lymphoma (NHL), multiple myeloma, acute and chronic lymphoid leukemia, and Parkinson's disease. WM crop farmers showed significantly higher mortality risk for cancer of the lip, skin, multiple myeloma, and chronic lymphoid leukemia. CONCLUSIONS: These disease trends suggested that livestock farmers might be exposed to more carcinogens or agricultural chemicals than crop farmers. 相似文献
992.
OBJECTIVE: To establish whether successful certifying examination performances of doctors are associated with their patients' mortality and length of stay following acute myocardial infarction. DESIGN: Risk adjusted mortality and survivors' length of stay were compared for doctors who had satisfactorily completed training in internal medicine or cardiology and attempted the relevant examination. Specifically, the study investigated the joint effects of hospital location, availability of advanced cardiac care, doctors' specializations, certifying examination performances, year certification was first attempted and patient volume. SETTING AND PARTICIPANTS: Data on all acute myocardial infarctions in Pennsylvania for the calendar year 1993 were collected by the Pennsylvania Health Care Cost Containment Council. These data were combined with physician information from the database of the American Board of Internal Medicine. RESULTS: Holding all variables constant, successful examination performance (i.e. certification in internal medicine or cardiology) was associated with a 19% reduction in mortality. Decreased mortality was also correlated with treatment in hospitals located outwith either rural or urban settings and with management by a cardiologist. Shorter stays were not related to examination performance but were associated with treatment by high volume cardiologists who had recently finished training and who cared for their patients in hospitals located outwith rural or urban settings. CONCLUSIONS: The results of the study add to the evidence supporting the validity of the certifying examination and lend support to the concept that fund of knowledge is related to quality of practice. 相似文献
993.
Effects of low body mass index and smoking on all-cause mortality among middle-aged and elderly Japanese 总被引:5,自引:0,他引:5
Miyazaki M Babazono A Ishii T Sugie T Momose Y Iwahashi M Une H 《Journal of epidemiology / Japan Epidemiological Association》2002,12(1):40-44
To investigate effects of low body mass index (BMI) and smoking on all-cause mortality among middle-aged and elderly Japanese, we conducted a community-based prospective study. A mail survey was conducted in 1987-1990 in four towns, western Japan. A cohort of 7,301 Japanese men and 8,825 Japanese women was followed up from the date of the mail survey to 1995 in three of the towns and 1998 in the fourth town. We investigated the effect of BMI and smoking on all-cause mortality by using Cox's proportional hazards model. The relationship between BMI and all-cause mortality was a reverse J-shape with minimal mortality in 24 < or = BMI < 26 in men and a U-shape with minimal mortality in 22 < or = BMI < 24 in women, after adjusting for age and smoking. The lowest BMI category (BM < 20) had the highest all-cause mortality in men and also in women. Taking only never-smokers, the highest risk for all-cause mortality was observed in the lowest BMI category for men and for women. This does not seem to be explained by smoking and pre-existing diseases. More attention should be paid to persons with low BMI. 相似文献
994.
Rodriguez C Jacobs EJ Patel AV Calle EE Feigelson HS Fakhrabadi-Shokoohi D Thun MJ 《Cancer causes & control : CCC》2002,13(3):271-277
Objective: To investigate prospectively the relationship between Jewish ethnicity and prostate cancer mortality. Methods: Men were selected from white male participants in two large American Cancer Society cohorts: Cancer Prevention Studies I (CPS-I) (enrolled in 1959 and followed through 1972) and II (CPS-II) (enrolled in 1982 and followed through 1996). During the follow-up periods there were 1751 prostate cancer deaths among 417,018 men in CPS-I and 3594 deaths among 447,780 men in CPS-II. Cox proportional hazards modeling was used to compute rate ratios (RR) and to adjust for known and suspected risk factors for prostate cancer. Results: Prostate cancer death rates were substantially lower among Jewish men than other white men in both cohorts (multivariate adjusted rate ratios (RR) = 0.54, 95% CI = 0.38–0.77 in CPS-I; RR = 0.72, 95% CI = 0.61–0.86 in CPS-II). Factors such as tobacco avoidance and measured dietary patterns did not account for this difference. Lower prostate cancer death rates were observed among Jewish men regardless of place of birth of the participants or their parents. Conclusions: Prostate cancer death rates are lower among Jewish men in the US and in Israel than among non-Jewish US white men. This may reflect persistent differences in unknown environmental risk factors or possible genetic susceptibility. 相似文献
995.
Postoperative morbidity,mortality, and survival in lung cancer associated with idiopathic pulmonary fibrosis 总被引:4,自引:0,他引:4
BACKGROUND: Although postoperative morbidity and mortality rates in patients with lung cancer have decreased with advances in perioperative management, those patients with idiopathic pulmonary fibrosis (IPF) remain at a high risk of complication and death. The frequency of postoperative morbidity and mortality rates in patients with lung cancer who have IPF have seldom been reported, however. METHODS: A retrospective study of 711 patients with lung cancer who had undergone surgical resection was conducted. Medical records were retrospectively compared for factors that might affect postoperative morbidity and mortality in patients with and without IPF. RESULTS: Of the 711 patients with lung cancer, 53 (7.5%) had IPF. The patients with IPF had pulmonary morbidity and mortality more frequently than those without IPF (26% versus 9.1%, P < 0.01; 8% versus 0.8%; P < 0.01). The 5-year survival was 43% among patients with IPF and 64.2% among those without IPF. Overall survival in patients with IPF was significantly lower than in those without IPF (P < 0.01), but disease-free survival was similar in the groups. Thirty-five percent of the deaths (8 of 23) were not related to lung cancer in those patients with IPF, compared with 18% (35 of 199) of the deaths among those without IPF (P = 0.048). CONCLUSION: Patients with IPF showed markedly higher postoperative pulmonary morbidity and mortality than those without IPF. The survival rate of patients with IPF was lower because of pulmonary complications. Careful preoperative evaluation and perioperative management are required to achieve optimal surgical outcome in patients with lung cancer who have IPF. 相似文献
996.
Targeting the optimal extent of lymph node dissection for gastric cancer 总被引:20,自引:0,他引:20
997.
Kodio B de Bernis L Ba M Ronsmans C Pison G Etard JF 《Tropical medicine & international health : TM & IH》2002,7(6):499-505
OBJECTIVES: To report the findings of a direct, community-based, assessment of maternal mortality and medical causes of death using verbal autopsy in three unique cohorts in rural Senegal. METHODS: Methods from ongoing demographic surveillance systems. We obtained records of all deaths and births in women of age 15-49 over a period of 14 years in Niakhar, 10 years in Bandafassi and 13 years in Mlomp. Relatives of all women who died were interviewed using a standard questionnaire. Causes of death were assigned by three physicians independently. Maternal deaths were defined according to the ninth and tenth revisions of the International Classification of Diseases. RESULTS: The maternal mortality ratio was similar in Mlomp [436 per 100 000 live births (95% confidence interval 209-802)] and Niakhar [516 per 100 000 (413-636)] but significantly higher in the more remote area of Bandafassi [852 (587-1196)] [relative risk compared with Niakhar 1.6 (1.0-2.4)]. Two-thirds of the maternal deaths were from direct obstetric causes, haemorrhage being the most common. Abortion was rare. CONCLUSIONS: Demographic surveillance systems are useful tools for the measurement of maternal mortality provided special studies are carried out to arrive at the levels and causes of maternal death. The estimates of maternal mortality reported here are lower than those published by the WHO and UNICEF but remain extremely high, particularly in the very remote areas with very limited health infrastructure, where as many as one in 19 women may be expected to die as a consequence of childbirth. 相似文献
998.
Torasemide in chronic heart failure: results of the TORIC study 总被引:16,自引:0,他引:16
BACKGROUND: Diuretics such as torasemide are commonly used to treat chronic heart failure (CHF). AIMS: The objective of the TOrasemide In Congestive Heart Failure (TORIC) Study was to investigate the safety, tolerability and efficacy of torasemide in CHF patients compared to furosemide or other diuretics in an open-label, non-randomised, post-marketing surveillance trial. METHODS: The present analysis shows the findings of 1377 patients with New York Heart Association (NYHA) class II-III CHF who received diuretic therapy with torasemide 10 mg/day orally (n=778) vs. patients who received furosemide 40 mg/day orally (n=527) or other diuretics (n=72) on top of their existing standard CHF therapy for 12 months. Besides safety and tolerability, efficacy was assessed by documentation of mortality, morbidity, functional class and serum potassium levels every 3 months. RESULTS: TORIC confirmed the safety and tolerability of torasemide in CHF patients. Mortality was significantly lower in the torasemide (n=17, 2.2%) than in the furosemide/other diuretics group (n=27, 4.5%) (P<0.05). Functional improvement as assessed by NYHA class was observed in more patients who received furosemide torasemide (n=356, 45.8%) than those who received furosemide/other diuretics (n=223, 37.2%) (P=0.00017). At the end of the study abnormally low serum potassium levels were observed in fewer torasemide (n=95, 12.9%) than furosemide/other diuretics patients (n=102, 17.9%) (P=0.013). CONCLUSION: Torasemide is safe and well tolerated in CHF patients. Although not designed as a mortality study, TORIC suggests a lower mortality amongst CHF patients treated with torasemide compared to furosemide/other diuretics. A functional improvement and a lower incidence of abnormal serum potassium levels were also observed in patients receiving torasemide as compared to those receiving furosemide/other diuretics. 相似文献
999.
Background: Granulocyte colony‐stimulating factor (G‐CSF) stimulates the production of neutrophils and modulates the function and activity of developing and mature neutrophils. In septic shock, the immune system can be considered one of the failing organ systems.G‐CSF improves immune function and may be a useful adjunctive therapy in patients with septic shock. Aim: To evaluate the introduction of G‐CSF as an adjunct to our standard treatment for community‐acquired septic shock. Methods: We performed a prospective data collection and analysis to determine whether the addition of G‐CSF to our standard treatment for community‐acquired septic shock was associated with improved hospital outcome, compared with an historical cohort ofsimilar patients. We included all patients admitted to the Intensive Care Unit (ICU) with community‐acquired septic shock between December 1998 and March 2000. Patients received 300 µg G‐CSF intravenously daily for 10 days in addition to ourstandard treatment for community‐acquired septic shock. G‐CSF was discontinued early if the patient was discharged from ICU before10 days or if the absolute neutrophil count exceeded 75 × 106/mL. Results: A total of 36 patients with community‐acquired septic shock, an average Apache 2 score of 26.7, and a predictedmortality of 0.79, were treated with G‐CSF from December 1998 to March 2000. Hospital mortality was 31% compared with an historical cohort of 11 similar patients with a hospital mortality of 73% (P = 0.018). In the subgroup of patients with melioidosis septic shock, the hospital survival improved from 5% to 100% (P < 0.0001).No significant adverse events occurred as a result of the administration of G‐CSF. Conclusion: G‐CSF is a safe adjunctive therapy in community‐acquired septic shock and may be associated with improved outcome. The use of G‐CSF in septic shock should undergo further investigation to define subgroups of patients who may benefit from G‐CSF. The use of G‐CSF in patients with septic shock due to Burkholderia pseudomallei is recommended. (Intern Med J 2002; 32: 143?148) 相似文献
1000.
Exercise-induced symptomatic ischaemia predicts a poor long-term prognosis after acute myocardial infarction 总被引:2,自引:0,他引:2
STUDY OBJECTIVES: To evaluate the long-term prognostic significance of symptomatic ischaemia during exercise testing performed 3 weeks after acute myocardial infarction (AMI). DESIGN: A prospective study with long-term follow-up. SETTING: A Cardiac Rehabilitation Clinic in a University Hospital. SUBJECTS: A total of 446 patients were allowed to perform exercise testing 3 weeks after AMI and followed for 72 +/- 20 months. MEASUREMENTS AND RESULTS: Patients were divided into three groups according to whether they had no ECG evidence of ischaemia during exercise testing (334 patients), silent ischaemia (90 patients) or symptomatic ischaemia (22 patients). Cardiac death was significantly more frequent in patients with symptomatic ischaemia when compared with silent ischaemia (31.8% vs. 7.8%, P < 0.01) or when compared with no ischaemia (31.8% vs. 10.2%, P < 0.01). The three groups had a low cardiac mortality during the first 48 months of follow-up. The prognosis of patients with symptomatic ischaemia worsens markedly thereafter. The results of exercise testing did not predict recurrence of myocardial infarction. Coronary revascularization was performed in 34.4% of those without ischaemia, 47.8% of those with silent ischaemia and 45.5% of those with symptomatic ischaemia (P < 0.01). CONCLUSIONS: Patients with symptomatic ischaemia have a good prognosis during the first 4 years of follow-up. Their prognosis worsens thereafter as opposed to patients with or without silent ischaemia. This high-risk group of patients with symptomatic ischaemia deserves optimal management including revascularization when appropriate. 相似文献