全文获取类型
收费全文 | 29771篇 |
免费 | 2187篇 |
国内免费 | 145篇 |
专业分类
耳鼻咽喉 | 93篇 |
儿科学 | 1664篇 |
妇产科学 | 676篇 |
基础医学 | 2749篇 |
口腔科学 | 117篇 |
临床医学 | 2967篇 |
内科学 | 9463篇 |
皮肤病学 | 501篇 |
神经病学 | 2352篇 |
特种医学 | 246篇 |
外科学 | 3232篇 |
综合类 | 695篇 |
现状与发展 | 1篇 |
一般理论 | 6篇 |
预防医学 | 2621篇 |
眼科学 | 1040篇 |
药学 | 1247篇 |
2篇 | |
中国医学 | 62篇 |
肿瘤学 | 2369篇 |
出版年
2024年 | 44篇 |
2023年 | 280篇 |
2022年 | 260篇 |
2021年 | 394篇 |
2020年 | 370篇 |
2019年 | 149篇 |
2018年 | 551篇 |
2017年 | 560篇 |
2016年 | 646篇 |
2015年 | 631篇 |
2014年 | 530篇 |
2013年 | 844篇 |
2012年 | 2382篇 |
2011年 | 2647篇 |
2010年 | 916篇 |
2009年 | 889篇 |
2008年 | 2762篇 |
2007年 | 2641篇 |
2006年 | 2279篇 |
2005年 | 2394篇 |
2004年 | 2422篇 |
2003年 | 2530篇 |
2002年 | 1955篇 |
2001年 | 1437篇 |
2000年 | 324篇 |
1999年 | 168篇 |
1998年 | 227篇 |
1997年 | 137篇 |
1996年 | 103篇 |
1995年 | 63篇 |
1994年 | 78篇 |
1993年 | 43篇 |
1992年 | 44篇 |
1991年 | 36篇 |
1990年 | 42篇 |
1989年 | 37篇 |
1988年 | 40篇 |
1987年 | 39篇 |
1986年 | 33篇 |
1985年 | 25篇 |
1984年 | 25篇 |
1983年 | 13篇 |
1982年 | 20篇 |
1981年 | 22篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1975年 | 5篇 |
1974年 | 6篇 |
1970年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Gompels MM Hodges E Lock RJ Angus B White H Larkin A Chapel HM Spickett GP Misbah SA Smith JL;Associated Study Group 《Clinical and experimental immunology》2003,134(2):314-320
We have undertaken a retrospective study of antibody deficient patients, with and without lymphoma, and assessed the ability of specific polymerase chain reaction (PCR) primers to determine if the detection of clonal lymphocyte populations correlates with clinical and immunohistochemical diagnosis of lymphoma. We identified 158 cases with antibody deficiency presenting during the past 20 years. Paraffin-embedded biopsy specimens or slides were available for analysis in a cohort of 34 patients. Of these patients, 29 had common variable immunodeficiency, one X-linked agammaglobulinaemia, one X-linked immunoglobulin deficiency of uncertain cause and three isolated IgG subclass deficiency. We have confirmed that lymphoma in antibody deficiency is predominantly B cell in origin. Clonal lymphocyte populations were demonstrated in biopsies irrespective of histology (16/19 with lymphoma and 11/15 without). Isolated evidence of clonality in biopsy material is therefore an insufficient diagnostic criterion to determine malignancy. Furthermore, our data suggest that clonal expansions are rarely the result of Epstein-Barr virus-driven disease. 相似文献
142.
Riedel F Adam S Feick P Haas S Götte K Hörmann K;Mannheim Alcohol Study Group 《International journal of molecular medicine》2004,13(2):267-272
Interleukin-18 (IL-18), a recently described cytokine secreted mainly by macrophages, stimulates interferon-gamma (IFN-gamma) production by natural killer cells and T cells. The purpose of this study was to determine tissue expression and serum levels of IL-18 in head and neck squamous cell carcinoma (HNSCC) and to evaluate ethanol and endotoxin-driven cytokine secretion. In 24 patients with primary HNSCC and 28 healthy controls, PBMC were isolated and incubated with 50 mM ethanol, LPS (doses 25 ng/ml, 250 ng/ml, 2500 ng/ml) and both agents for 24 h. Levels of IL-18 in serum, and cell supernatants were analysed by capture ELISA, IL-18 tissue level by immunoblotting. Serum levels of IL-8, IL-10 and IL-12, IFN-gamma, and endotoxin plasma levels were also determined. Statistical analysis involved Welch t-test and Page's test for trend. The majority of patients with HNSCC had high concentrations of serum IL-18. The level of IL-18 in the sera of these patients had a mean level of 271.7 pg/ml, while the mean IL-18 serum level in healthy controls was 174,0 pg/ml (p<0.001). Levels of IL-10 and IL-12, IFN-gamma were not increased in patients. Endotoxin was not detectable in either group. LPS stimulated dose-dependently IL-18 secretion from PBMC of patients and controls in vitro (p<0.05). Incubation with ethanol alone did not affect basal IL-18 secretion, but ethanol reduced LPS-stimulated IL-18 secretion compared to LPS stimulation alone. The mRNA expression of IL-18 in unstimulated PBMC and the response of PBMC to ethanol and LPS was similar in patients and controls. Our data on elevated serum levels of IL-18 in the majority of HNSCC cancer patients, irrespective of its biological activity, suggest that serum IL-18 might be a candidate for a new marker for HNSCC. The pathways for IL-18 production and its mechanisms of action in patients with HNSCC remain to be determined. Understanding of the immunological pathways might offer new therapeutic options in head and neck cancer in the future. 相似文献
143.
Moyle GJ Daar ES Gertner JM Kotler DP Melchior JC O'brien F Svanberg E;Serono Study Team 《Journal of acquired immune deficiency syndromes (1999)》2004,35(4):367-375
HIV-associated wasting is defined as > or = 10% involuntary weight loss and includes declines in both lean and fat mass. This large (757 subjects), randomized, double-blind, placebo-controlled trial investigated the efficacy, safety, and tolerability of recombinant human growth hormone (rhGH) in 2 doses-0.1 mg/kg up to a maximum of 6 mg daily (DD) or alternate days (AD)-in the treatment of wasting and weight loss in highly active antiretroviral therapy (HAART)-treated HIV-infected subjects. The evaluable population for ergometry comprised 555 subjects, 87.6% of whom were receiving HAART. At 12 weeks, median maximum work output increased by 2.4 and 2.6 kJ in the AD and DD groups, respectively. The median treatment difference was 2.9 kJ for DD vs. placebo (P < 0.0001). Body weight increased by 2.2 and 2.9 kg in the AD and DD groups, respectively. Corresponding median treatment differences vs. placebo were 1.5 and 2.2 kg (P < 0.0001). Lean body mass (LBM), by bioelectric impedance spectroscopy, increased by 3.3 and 5.2 kg, respectively (P < 0.0001 vs. placebo; P = 0.0173 DD vs. AD), and fat mass, predominately truncal, decreased. Quality of life (QoL) improved significantly in both rhGH groups. Fluid-retention adverse effects and hyperglycemia were more common in the DD than in the AD group. No significant changes in HIV viral load or CD4 cell count occurred. In conclusion, over the 12-week course of therapy, rhGH, 0.1 mg/kg DD, was superior to placebo in improving physical function, body weight, body composition, and QoL and was superior to AD dosing in restoring LBM. 相似文献
144.
145.
Bozzette SA Joyce G McCaffrey DF Leibowitz AA Morton SC Berry SH Rastegar A Timberlake D Shapiro MF Goldman DP;HIV Cost Services Utilization Study Consortium 《The New England journal of medicine》2001,344(11):817-823
BACKGROUND: The introduction of expensive but very effective antiviral medications has led to questions about the effects on the total use of resources for the care of patients with human immunodeficiency virus (HIV) infection. We examined expenditures for the care of HIV-infected patients since the introduction of highly active antiretroviral therapy. METHODS: We interviewed a random sample of 2864 patients who were representative of all American adults receiving care for HIV infection in early 1996, and followed them for up to 36 months. We estimated the average expenditure per patient per month on the basis of self-reported information about care received. RESULTS: The mean expenditure was $1,792 per patient per month at base line, but it declined to $1,359 for survivors in 1997, since the increases in pharmaceutical expenditures were smaller than the reductions in hospital costs. Use of highly active antiretroviral therapy was independently associated with a reduction in expenditures. After adjustments for the interview date, clinical status, and deaths, the estimated annual expenditure declined from $20,300 per patient in 1996 to $18,300 in 1998. Expenditures among subgroups of patients varied by a factor of as much as three. Pharmaceutical costs were lowest and hospital costs highest among underserved groups, including blacks, women, and patients without private insurance. CONCLUSIONS: The total cost of care for adults with HIV infection has declined since the introduction of highly active antiretroviral therapy. Expenditures have increased for medications but have declined for other services. However, there are large variations in expenditures across subgroups of patients. 相似文献
146.
147.
Clinical,immunological, and molecular analysis in a large cohort of patients with X-linked agammaglobulinemia: an Italian multicenter study 总被引:5,自引:0,他引:5
Plebani A Soresina A Rondelli R Amato GM Azzari C Cardinale F Cazzola G Consolini R De Mattia D Dell'Erba G Duse M Fiorini M Martino S Martire B Masi M Monafo V Moschese V Notarangelo LD Orlandi P Panei P Pession A Pietrogrande MC Pignata C Quinti I Ragno V Rossi P Sciotto A Stabile A;Italian Pediatric Group for XLA-AIEOP 《Clinical immunology (Orlando, Fla.)》2002,104(3):221-230
A questionnaire-based retrospective clinical and immunological survey was conducted in 73 males with a definite diagnosis of X-linked agammaglobulinemia based on BTK sequence analysis. Forty-four were sporadic and 29 familial cases. At December 2000, the patients' ages ranged from 2 to 33 years; mean age at diagnosis and mean duration of follow-up were 3.5 and 10 years respectively. After the mid-1980s all but 2 were on intravenous immunoglobulin (IVIG) substitution therapy, with residual IgG >500 mg/dl in 94% of the patients at the time of enrollment. Respiratory infections were the most frequent manifestation both prior to diagnosis and over follow-up. Chronic lung disease (CLD) was present in 24 patients, in 15 already at diagnosis and in 9 more by 2000. The cumulative risk to present at diagnosis with CLD increased from 0.17 to 0.40 and 0.78 when the diagnosis was made at the ages of 5, 10, and 15 years respectively. For the 9 patients who developed CLD during follow-up, the duration of follow-up, rather than age at diagnosis; previous administration of intramuscular immunoglobulin; and residual IgG levels had a significant effect on the development of CLD. Chronic sinusitis was present in 35 patients (48%), in 15 already at diagnosis and in 20 by 2000. Sistemic infections such as sepsis and meningitis/meningoencephalitis decreased over follow-up, probably due to optimal protection provided by high circulating IgG levels reached with IVIG. 相似文献
148.
Jones RN Anderegg TR Swenson JM;Quality Control Working Group 《Journal of clinical microbiology》2005,43(2):925-927
An eight-laboratory study addressed the urgent need for quality control (QC) ranges for susceptibility determination when testing colistin (polymyxin E) and polymyxin B, two polycationic peptide antimicrobial agents, against multidrug-resistant gram-negative bacilli. For Escherichia coli ATCC 25922l, the QC ranges were as follows: for colistin, 0.25 to 1 microg/ml (11 to 17 mm), and for polymyxin B, 0.25 to 2 microg/ml (13 to 19 mm). For Pseudomonas aeruginosa ATCC 27853, the QC ranges were as follows: for colistin, 0.25 to 2 microg/ml (11 to 17 mm), and for polymyxin B, 0.25 to 2 mug/ml (14 to 18 mm). More than 97% of all reported QC results were within these proposed ranges. 相似文献
149.
150.
A reevaluation of the duration of survival after the onset of dementia 总被引:15,自引:0,他引:15
Wolfson C Wolfson DB Asgharian M M'Lan CE Ostbye T Rockwood K Hogan DB;Clinical Progression of Dementia Study Group 《The New England journal of medicine》2001,344(15):1111-1116
BACKGROUND: Dementia shortens life expectancy; estimates of median survival after the onset of dementia have ranged from 5 to 9.3 years. Previous studies of people with existing dementia, however, may have underestimated the deleterious effects of dementia on survival by failing to consider persons with rapidly progressive illness who died before they could be included in a study (referred to as length bias). METHODS: We used data from the Canadian Study of Health and Aging to estimate survival from the onset of symptoms of dementia; the estimate was adjusted for length bias. A random sample of 10,263 subjects 65 years old or older from throughout Canada was screened for cognitive impairment. For those with dementia, we ascertained the date of onset and conducted follow-up for five years. RESULTS: We analyzed data on 821 subjects, of whom 396 had probable Alzheimer's disease, 252 had possible Alzheimer's disease, and 173 had vascular dementia. For the group as a whole, the unadjusted median survival was 6.6 years (95 percent confidence interval, 6.2 to 7.1). After adjustment for length bias, the estimated median survival was 3.3 years (95 percent confidence interval, 2.7 to 4.0). The median survival was 3.1 years for subjects with probable Alzheimer's disease, 3.5 years for subjects with possible Alzheimer's disease, and 3.3 years for subjects with vascular dementia. CONCLUSIONS: Median survival after the onset of dementia is much shorter than has previously been estimated. 相似文献