全文获取类型
收费全文 | 35490篇 |
免费 | 2638篇 |
国内免费 | 81篇 |
专业分类
耳鼻咽喉 | 306篇 |
儿科学 | 1155篇 |
妇产科学 | 987篇 |
基础医学 | 4902篇 |
口腔科学 | 770篇 |
临床医学 | 5813篇 |
内科学 | 6084篇 |
皮肤病学 | 493篇 |
神经病学 | 3228篇 |
特种医学 | 735篇 |
外国民族医学 | 2篇 |
外科学 | 3206篇 |
综合类 | 420篇 |
一般理论 | 67篇 |
预防医学 | 4576篇 |
眼科学 | 388篇 |
药学 | 2168篇 |
中国医学 | 36篇 |
肿瘤学 | 2873篇 |
出版年
2023年 | 181篇 |
2022年 | 249篇 |
2021年 | 541篇 |
2020年 | 486篇 |
2019年 | 795篇 |
2018年 | 849篇 |
2017年 | 668篇 |
2016年 | 777篇 |
2015年 | 842篇 |
2014年 | 1078篇 |
2013年 | 1704篇 |
2012年 | 2284篇 |
2011年 | 2314篇 |
2010年 | 1307篇 |
2009年 | 1224篇 |
2008年 | 2202篇 |
2007年 | 2338篇 |
2006年 | 2365篇 |
2005年 | 2227篇 |
2004年 | 2062篇 |
2003年 | 1997篇 |
2002年 | 1913篇 |
2001年 | 483篇 |
2000年 | 449篇 |
1999年 | 454篇 |
1998年 | 473篇 |
1997年 | 386篇 |
1996年 | 355篇 |
1995年 | 350篇 |
1994年 | 300篇 |
1993年 | 291篇 |
1992年 | 305篇 |
1991年 | 283篇 |
1990年 | 259篇 |
1989年 | 254篇 |
1988年 | 252篇 |
1987年 | 203篇 |
1986年 | 221篇 |
1985年 | 208篇 |
1984年 | 211篇 |
1983年 | 180篇 |
1982年 | 194篇 |
1981年 | 183篇 |
1980年 | 185篇 |
1979年 | 109篇 |
1978年 | 127篇 |
1977年 | 104篇 |
1976年 | 107篇 |
1975年 | 120篇 |
1974年 | 107篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Jaccoud arthropathy (JA), now most commonly associated with systemic lupus erythematosus (SLE), is widely perceived as a benign joint deformity that is radiographically nonerosive and that confers little if any disability. Advances and accessibility of imaging modalities such as ultrasound (US) are challenging the complacency in perceiving SLE-JA and SLE arthritis as benign processes. Prompted by a patient with SLE-JA in which joint erosion was detectable on US but not evident on radiograph, this review assesses the potential utility of US to guide management and promote understanding of SLE arthritis and its poorly understood pathogenesis. 相似文献
23.
Michael Schenker Mikael Wiberg Simon P Kay Roland S Johansson 《Journal of plastic, reconstructive & aesthetic surgery》2007,60(1):13-23
Although toe-to-hand transfer has a defined role in the management of congenital hand deformities, it remains unclear how well children integrate the transferred digits into physiological grasping. We analysed fingertip forces in the precision grip of 13 patients when lifting a test object more than three years after free toe transfer for absent or hypoplastic digits. Clinically, most patients showed normal sensibility of transferred digits, but active motion and pinch strength were limited as compared to the normal hand. For the control of fingertip forces, two key features of the normal two-digit opposition grip were seen in all operated hands: adaptation of grip force to object weight and parallel coordination of lift and grip forces. These physiological grasping strategies developed independently of the patients' age at the time of operation, which ranged from one to 13 years. In four patients, we observed increased tangential load forces with the operated hand due to misalignments in the application of fingertips on the grasp surfaces. Such forces lead to increased grip force requirements on both fingers that may overload transferred digits with limited motor function. The need for optimal alignment of the grip axis during toe-transfer surgery is emphasised. 相似文献
24.
25.
26.
M. Scott DeBerard Rick A. LaCaille Glen Spielmans Alan Colledge Mary Ann Parlin 《The spine journal》2009,9(3):193-203
Background contextLumbar discectomy is the most common type of back surgery performed in the United States. Outcomes after this procedure can be variable and it appears that Workers' Compensation patients might be at increased risk for poor outcomes.PurposeTo examine long-term multidimensional outcomes of lumbar discectomy within a cohort of Workers' Compensation patients from Utah and identify presurgical biopsychosocial factors related to poor outcomes.Study design/settingA retrospective cohort study consisting of a review of presurgical medical records and assessment of patient outcomes via a telephone survey. Outcomes were assessed at least 2 years postsurgery.Patient sampleA consecutive sample of 271 workers from Utah who underwent lumbar discectomy from 1994 to 1999. A total of 134 patients were surveyed at the time of follow-up.Outcome measuresPatient satisfaction, Roland-Morris Disability Questionnaire, SF-36v2, and Stauffer-Coventry Index.MethodsA retrospective review of presurgical biopsychosocial variables and outcome assessment via telephone survey was conducted.ResultsWork disability rate for the cohort was 12.7% (17/134). Analysis of patient satisfaction, back pain-related dysfunction, and the Short-Form Health Survey-36 subscales indicated approximately 25% of patients experienced poor outcomes. Older age, number of comorbid health conditions, assigned case manager, litigation, and time delay from injury to surgery were consistently statistically significant predictors (p<.05) of poor outcomes.ConclusionsResults of this study suggest that compensated back surgery patients are at greater risk for poor lumbar discectomy outcomes than noncompensation patients. Presurgery correlates of poor outcomes may be useful in identifying high-risk compensation patients. 相似文献
27.
L Joseph Melton S Vincent Rajkumar Sundeep Khosla Sara J Achenbach Ann L Oberg Robert A Kyle 《Journal of bone and mineral research》2004,19(1):25-30
To assess fractures in monoclonal gammopathy of undetermined significance (MGUS), the precursor of multiple myeloma, we followed 488 Olmsted County, MN, residents with MGUS in a retrospective cohort study. There was a 2.7-fold increase in the risk of axial fractures but no increase in limb fractures. The pathophysiologic basis for the increased axial fractures should be determined. INTRODUCTION: Multiple myeloma is often preceded by monoclonal gammopathy of undetermined significance (MGUS). Fractures are common in myeloma as a result of lytic bone lesions, generalized bone loss, and elevated bone turnover from excessive cytokine production. Whether fractures are also increased in MGUS is unknown. MATERIALS AND METHODS: In a population-based retrospective cohort study, 488 Olmsted County, MN, residents with MGUS first diagnosed in 1960-1994 (52% men; mean age, 71.4 +/- 12.8 years) were followed for 3901 person-years; follow-up was censored at progression to myeloma. The relative risk of fractures was assessed by standardized incidence ratios (SIRs), and risk factors were evaluated in proportional hazards models. RESULTS AND CONCLUSIONS: Altogether, 200 patients experienced 385 fractures. Compared with expected rates in the community, statistically significant increases were seen for fractures at most axial sites, for example, vertebrae (SIR, 6.3; 95% CI, 5.2-7.5). There was a slight increase in hip (SIR, 1.6; 95% CI, 1.2-2.2) but not distal forearm fractures (SIR, 0.8; 95% CI, 0.4-1.5). The relative risk (SIR) of any axial fracture was 2.7 (95% CI, 2.3-3.1) compared with only 1.1 (95% CI, 0.9-1.4) for all limb fractures combined. In a multivariate analysis, the independent predictors of any subsequent fracture were age (hazard ratio [HR] per 10-year increase, 1.4; 95% CI, 1.2-1.6) and corticosteroid use (HR, 1.8; 95% CI, 1.2-2.6); greater weight at diagnosis (HR per 10 kg, 0.8; 95% CI, 0.8-0.9), and IgG monoclonal protein (HR, 0.7; 95% CI, 0.5-0.97) were protective. Baseline monoclonal protein level, a determinant of myeloma progression, did not predict fracture risk. Thus, the risk of axial, but not peripheral, fractures is increased among MGUS patients even before progression to myeloma. The pathophysiologic basis for this should be determined because elevated bone turnover, for example, might be treatable. 相似文献
28.
Frederica Perera Deliang Tang Robin Whyatt Sally Ann Lederman Wieslaw Jedrychowski 《Cancer epidemiology, biomarkers & prevention》2005,14(3):709-714
Polycyclic aromatic hydrocarbons (PAH), of which benzo[a]pyrene is a representative member, are combustion-related environmental pollutants and include known carcinogens. Laboratory animal studies indicate that the dose of PAHs to the fetus is on the order of a 10th that to the mother and that there is heightened susceptibility to PAH-induced carcinogenesis during the fetal and infancy periods. Carcinogen-DNA adducts, a measure of procarcinogenic genetic damage, are considered a biomarker of increased cancer risk. Here we compare the levels of benzo[a]pyrene-DNA adducts as a proxy for PAH-DNA damage measured in maternal blood and newborn cord blood obtained at delivery in four different populations of mothers (total of 867) and newborns (total of 822), representing a 30-fold range of exposure to ambient PAHs. The populations include residents in Northern Manhattan, participants in a study of the effects of the World Trade Center disaster, residents in Krakow, Poland, and residents in Tongliang, China. Mean adduct concentrations in both maternal and cord blood and the proportion of samples with detectable adducts, increased across the populations [Northern Manhattan < World Trade Center (WTC) < Krakow < Tongliang], consistent with the trend in estimated ambient exposure to PAHs (P < 0.001). For mothers, the means in the respective populations were Northern Manhattan (0.21 adducts per 10(8) nucleotides), WTC (0.23 adducts per 10(8) nucleotides), Krakow (0.28 adducts per 10(8) nucleotides), Tongliang (0.31 adducts per 10(8) nucleotides); the corresponding means in the newborns were Northern Manhattan (0.23), WTC (0.24), Krakow (0.29), Tongliang (0.31). The percentage of mothers with detectable levels of adducts in the respective populations were Northern Manhattan (36.8%), WTC (57.5%), Krakow (72.9%), Tongliang (73.4%); the corresponding percentages among the newborns were Northern Manhattan (42.4%), WTC (60.6%), Krakow (71.1%), Tongliang (79.5%). Despite the estimated 10-fold lower PAH dose to the fetus based on laboratory animal experiments, the adduct levels in the newborns were similar to or higher than in the mothers. This study suggests that the fetus may be 10-fold more susceptible to DNA damage than the mother and that in utero exposure to polycyclic aromatic hydrocarbons may disproportionately increase carcinogenic risk. The data support preventive policies to limit PAH exposure to pregnant women and children. 相似文献
30.
David G Hicks Brian J Yoder Sarah Short Shannon Tarr Nichole Prescott Joseph P Crowe Andrea E Dawson G Thomas Budd Steven Sizemore Muzaffer Cicek Toni K Choueiri Raymond R Tubbs Daniel Gaile Norma Nowak Mary Ann Accavitti-Loper Andra R Frost Danny R Welch Graham Casey 《Clinical cancer research》2006,12(22):6702-6708
PURPOSE: This study aims to determine the effect of loss of breast cancer metastasis suppressor 1 (BRMS1) protein expression on disease-free survival in breast cancer patients stratified by estrogen receptor (ER), progesterone receptor (PR), or HER2 status, and to determine whether loss of BRMS1 protein expression correlated with genomic copy number changes. EXPERIMENTAL DESIGN: A tissue microarray immunohistochemical analysis was done on tumors of 238 newly diagnosed breast cancer patients who underwent surgery at the Cleveland Clinic between January 1, 1995 and December 31, 1996, and a comparison was made with 5-year clinical follow-up data. Genomic copy number changes were determined by array-based comparative genomic hybridization in 47 breast cancer cases from this population and compared with BRMS1 staining. RESULTS: BRMS1 protein expression was lost in nearly 25% of cases. Patients with tumors that were PR negative (P=0.006) or HER2 positive (P=0.039) and <50 years old at diagnosis (P=0.02) were more likely to be BRMS1 negative. No overall correlation between BRMS1 staining and disease-free survival was observed. A significant correlation, however, was seen between loss of BRMS1 protein expression and reduced disease-free survival when stratified by either loss of ER (P=0.008) or PR (P=0.029) or HER2 overexpression (P=0.026). Overall, there was poor correlation between BRMS1 protein staining and copy number status. CONCLUSIONS: These data suggest a mechanistic relationship between BRMS1 expression, hormone receptor status, and HER2 growth factor. BRMS1 staining could potentially be used in patient stratification in conjunction with other prognostic markers. Further, mechanisms other than genomic deletion account for loss of BRMS1 gene expression in breast tumors. 相似文献