全文获取类型
收费全文 | 1323458篇 |
免费 | 86017篇 |
国内免费 | 1753篇 |
专业分类
耳鼻咽喉 | 18718篇 |
儿科学 | 43360篇 |
妇产科学 | 37506篇 |
基础医学 | 191028篇 |
口腔科学 | 36174篇 |
临床医学 | 115528篇 |
内科学 | 249590篇 |
皮肤病学 | 29782篇 |
神经病学 | 99056篇 |
特种医学 | 52406篇 |
外国民族医学 | 241篇 |
外科学 | 201946篇 |
综合类 | 28330篇 |
现状与发展 | 2篇 |
一般理论 | 413篇 |
预防医学 | 92046篇 |
眼科学 | 30536篇 |
药学 | 103560篇 |
7篇 | |
中国医学 | 3439篇 |
肿瘤学 | 77560篇 |
出版年
2019年 | 9646篇 |
2018年 | 14301篇 |
2017年 | 11107篇 |
2016年 | 12670篇 |
2015年 | 14151篇 |
2014年 | 19166篇 |
2013年 | 28436篇 |
2012年 | 38160篇 |
2011年 | 40302篇 |
2010年 | 24268篇 |
2009年 | 22580篇 |
2008年 | 37368篇 |
2007年 | 40176篇 |
2006年 | 40543篇 |
2005年 | 38621篇 |
2004年 | 37087篇 |
2003年 | 35445篇 |
2002年 | 34121篇 |
2001年 | 70359篇 |
2000年 | 72038篇 |
1999年 | 59846篇 |
1998年 | 14938篇 |
1997年 | 13306篇 |
1996年 | 13166篇 |
1995年 | 12399篇 |
1994年 | 11244篇 |
1993年 | 10700篇 |
1992年 | 44484篇 |
1991年 | 43077篇 |
1990年 | 42384篇 |
1989年 | 40820篇 |
1988年 | 36775篇 |
1987年 | 35735篇 |
1986年 | 33702篇 |
1985年 | 31782篇 |
1984年 | 23104篇 |
1983年 | 19605篇 |
1982年 | 10878篇 |
1979年 | 20793篇 |
1978年 | 14196篇 |
1977年 | 12570篇 |
1976年 | 11023篇 |
1975年 | 12526篇 |
1974年 | 14548篇 |
1973年 | 14217篇 |
1972年 | 13487篇 |
1971年 | 12680篇 |
1970年 | 11754篇 |
1969年 | 11256篇 |
1968年 | 10167篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
A I D'hulst K R Bracke T Maes J L De Bleecker R A Pauwels G F Joos G G Brusselle 《The European respiratory journal》2006,28(1):102-112
Chronic obstructive pulmonary disease (COPD) is characterised by a local pulmonary inflammatory response to respiratory pollutants and by systemic inflammation. Tumour necrosis factor (TNF)-alpha has been implicated in systemic effects of COPD and operates by binding the p55 (R1) and p75 (R2) TNF-alpha receptors. To investigate the contribution of each TNF-alpha receptor in the pathogenesis of COPD, the present study examined the effects of chronic air or cigarette smoke (CS) exposure in TNF-alpha R1 knockout (KO) mice, TNF-alpha R2 KO mice and wild type (WT) mice. CS was found to significantly increase the protein levels of soluble TNF-alpha R1 (by four-fold) and TNF-alpha R2 (by 10-fold) in the bronchoalveolar lavage of WT mice. After 3 months, CS induced a prominent pulmonary inflammatory cell influx in WT and TNF-alpha R1 KO mice. In TNF-alpha R2 KO mice, CS-induced pulmonary inflammation was clearly attenuated. After 6 months, no emphysema was observed in CS-exposed TNF-alpha R2 KO mice in contrast to WT and TNF-alpha R1 KO mice. CS-exposed WT and TNF-alpha R1 KO mice failed to gain weight, whereas the body mass of TNF-alpha R2 KO mice was not affected. These current findings suggest that both tumour necrosis factor-alpha receptors contribute to the pathogenesis of chronic obstructive pulmonary disease, but tumour necrosis factor-alpha receptor-2 is the most active receptor in the development of inflammation, emphysema and systemic weight loss in this murine model of chronic obstructive pulmonary disease. 相似文献
22.
Characteristics and outcome of patients with active pulmonary tuberculosis requiring intensive care.
R Erbes K Oettel M Raffenberg H Mauch M Schmidt-Ioanas H Lode 《The European respiratory journal》2006,27(6):1223-1228
Severe tuberculosis (TB) requiring intensive care unit (ICU) care is rare but commonly known to be of markedly bad prognosis. The present study aimed to describe this condition and to determine the mortality rate and risk factors associated with mortality. Patients with confirmed TB admitted to ICU between 1990 and 2001 were retrospectively identified and enrolled. Clinical, radiological and bacteriological data at admission and during hospital stay were recorded. A multivariate analysis was performed to identify the predictive factors for mortality. A total of 58 TB patients (12 females, mean age 48 yrs) admitted to ICU were included. Mean Acute Physiology and Chronic Health Evaluation (APACHE) II score at admission was 13.1+/-5.6 and 22 of 58 (37.9%) patients required mechanical ventilation. The in-hospital mortality was 15 of 58 (25.9%); 13 (22.4%) patients died in the ICU. The mean survival of patients who died was 53.6 days (range 1-229), with 50% of the patients dying within the first 32 days. The factors independently associated with mortality were: acute renal failure, need for mechanical ventilation, chronic pancreatitis, sepsis, acute respiratory distress syndrome, and nosocomial pneumonia. These data indicate a high mortality of patients with tuberculosis requiring intensive care unit care and identifies new independently associated risk factors. 相似文献
23.
24.
Sebastian Bonner Thomas Matte Mitchell Rubin Joanne K Fagan Jennifer Ahern David Evans 《The Journal of asthma》2006,43(1):31-35
Although studies have documented underuse of controller medications and overuse of short-acting inhaled ss(2)-agonist among children with persistent asthma in disadvantaged communities, the persistence of oral ss(2)-agonist use in pediatric practice has not been studied since inhaled short-acting ss(2)-agonists became widespread. We describe medications used to treat asthma among children 3 to 5 years of age at 10 Head Start and other subsidized preschool centers in East and Central Harlem, New York City. We interviewed 149 parents/guardians of children who were identified as having probable asthma based on physician's diagnosis, persistent symptoms, hospitalization, and medication use. We classified 86 of the 149 children (58%) as having current persistent asthma. Only 15 of them (17%) were reported to have used controller medications at least 5 days/week in the last 4 weeks-only 2 of whom used inhaled corticosteroids. By contrast, 53 children (62%) used oral ss(2)-agonist in the last 4 weeks, often (72%) in conjunction with nebulized or inhaled short-acting ss(2)-agonist. Use of oral ss(2)-agonist was associated with more severe symptoms. This study documents the continued widespread use of oral ss(2)-agonist for treatment of children in a low-income community with high prevalence of asthma. 相似文献
25.
26.
27.
28.
Burkitt’s lymphoma is a high-grade, rapidly growing B-cell neoplasm. It is recognized by its aggressive course, brief median survival, and low rates of long-term survival. The authors discuss the case of a patient who acutely presented with intraabdominal complications from a new onset of Burkitt’s lymphoma. The clinical and pathological features, staging, treatment options, and survival data are reviewed. In addition, the role of surgical intervention is carefully analyzed. 相似文献
29.
La Creis R Kidd K Woodson P R Taylor D Albanes J Virtamo J A Tangrea 《European journal of cancer prevention》2003,12(4):317-320
Glutathione-S-transferase (GST) genes encode a family of detoxification enzymes that offer protection against endogenous and exogenous sources of reactive oxygen species (ROS). Germline variations in GST genes may alter the catalytic efficiency of GST isoenzymes leading to a potential increase in susceptibility to the genotoxic effects of ROS and electrophilic substances. A nested case-control study design was used to examine the association between the polymorphic GST genes and prostate cancer risk among Finnish male smokers of the ATBC Cancer Prevention Study. A case-case analysis was used to determine the association between these genetic polymorphisms and prostate cancer progression. Germline DNA was obtained from 206 prostate cancer cases and 194 controls frequency matched on age, intervention group and study clinic. Cases and controls were genotyped for three GST genes using MALDI-TOF mass spectrometry or multiplex polymerase chain reaction (PCR). Relative to the wild-type genotype, we observed a 36% reduction in prostate cancer risk associated with the GST-M1-null genotype (odds ratio (OR) 0.64, 95% confidence interval (CI) 0.43, 0.95). Unlike GST-M1, GST-T1-null (OR 0.74, 95% CI 0.42, 1.33) and GST-P1*B (OR 1.10, 95% CI 0.72, 1.69) were not strongly associated with prostate cancer risk. We did not observe any significant associations between the selected polymorphic GST genes and tumour grade or stage. In conclusion, we did not observe a direct association between polymorphic GST-T1 or GST-P1 and prostate cancer risk. Our observation of a relatively strong inverse association between the GST-M1-null genotype and prostate cancer risk needs to be confirmed in larger association studies. 相似文献
30.
J Phua E S C Koay D Zhang L K Tai X L Boo K C Lim T K Lim 《The European respiratory journal》2006,28(4):695-702
Levels of the soluble form of the triggering receptor expressed on myeloid cells (sTREM)-1 are elevated in severe sepsis. However, it is not known whether sTREM-1 measurements can distinguish milder bacterial infections from noninfectious inflammation. The present authors studied whether serum sTREM-1 levels differ in community-acquired pneumonia, exacerbations of chronic obstructive pulmonary disease (COPD), asthma and controls, and whether sTREM-1 may be used as a surrogate marker for the need for antibiotics. Serum sTREM-1 levels in 150 patients with pneumonia, COPD and asthma exacerbations and 62 healthy controls were measured. Serum sTREM-1 levels were significantly elevated in pneumonia (median 295.2 ng x mL(-1)), COPD (280.3 ng x mL(-1)) and asthma exacerbations (184.0 ng x mL(-1)) compared with controls (83.1 ng x mL(-1)). Levels were higher in pneumonia and Anthonisen type 1 COPD exacerbations than in type 2 and 3 COPD and asthma exacerbations. The area under the receiver operating characteristics curve for sTREM-1 as a surrogate marker for the need for antibiotics was 0.77. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 were elevated predominantly in pneumonia and Anthonisen type 1 COPD exacerbations versus type 2 and 3 chronic obstructive pulmonary disease exacerbations, asthma and controls. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 has moderate but insufficient accuracy as a surrogate marker for the need for antibiotics in lower respiratory tract infections. 相似文献