全文获取类型
收费全文 | 2365篇 |
免费 | 124篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 160篇 |
妇产科学 | 64篇 |
基础医学 | 370篇 |
口腔科学 | 50篇 |
临床医学 | 169篇 |
内科学 | 358篇 |
皮肤病学 | 77篇 |
神经病学 | 243篇 |
特种医学 | 22篇 |
外国民族医学 | 1篇 |
外科学 | 314篇 |
综合类 | 58篇 |
一般理论 | 2篇 |
预防医学 | 146篇 |
眼科学 | 61篇 |
药学 | 172篇 |
中国医学 | 5篇 |
肿瘤学 | 209篇 |
出版年
2023年 | 26篇 |
2022年 | 58篇 |
2021年 | 101篇 |
2020年 | 45篇 |
2019年 | 74篇 |
2018年 | 62篇 |
2017年 | 55篇 |
2016年 | 75篇 |
2015年 | 78篇 |
2014年 | 130篇 |
2013年 | 144篇 |
2012年 | 211篇 |
2011年 | 255篇 |
2010年 | 104篇 |
2009年 | 83篇 |
2008年 | 143篇 |
2007年 | 120篇 |
2006年 | 105篇 |
2005年 | 101篇 |
2004年 | 93篇 |
2003年 | 86篇 |
2002年 | 61篇 |
2001年 | 30篇 |
2000年 | 37篇 |
1999年 | 20篇 |
1998年 | 13篇 |
1997年 | 16篇 |
1996年 | 10篇 |
1995年 | 11篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 15篇 |
1991年 | 18篇 |
1990年 | 11篇 |
1989年 | 12篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 14篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 10篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1971年 | 4篇 |
排序方式: 共有2499条查询结果,搜索用时 0 毫秒
1.
Objective. To determine if patients treated at hospitals under different levels of financial strain from the Balanced Budget Act (BBA) of 1997 had differential changes in 30-day mortality, and whether vulnerable patient populations such as the uninsured were disproportionately affected.
Data Source. Hospital discharge data from all general acute care hospitals in Pennsylvania from 1997 to 2001.
Study Design. A multivariate regression analysis was performed retrospectively on 30-day mortality rates, using hospital discharge data, hospital financial data, and death certificate information from Pennsylvania.
Data Collection. We used 370,017 hospital episodes with one of four conditions identified by the Agency for Healthcare Research and Quality as inpatient quality indicators were extracted.
Principal Findings. The average magnitude of Medicare payment reduction on overall net revenues was estimated at 1.8 percent for hospitals with low BBA impact and 3.6 percent for hospitals with a high impact in 1998, worsening to 2 and 4.8 percent, respectively, by 2001. Operating margins decreased significantly over the time period for all hospitals ( p <.05). While unadjusted mortality rates demonstrated a disproportionate rise in mortality for patients from high impact hospitals from 1997 to 2000, adjusted analyses show no consistent, significant difference in the rate of change in mortality between high-impact and low-impact hospitals ( p =.04–.94). Similarly, uninsured patients did not experience greater increases in mortality in high-impact hospitals relative to low-impact hospitals.
Conclusions. An analysis of hospitalizations in the Commonwealth of Pennsylvania did not find an adverse impact of increased financial strain from the BBA on patient mortality either among all patients or among the uninsured. 相似文献
Data Source. Hospital discharge data from all general acute care hospitals in Pennsylvania from 1997 to 2001.
Study Design. A multivariate regression analysis was performed retrospectively on 30-day mortality rates, using hospital discharge data, hospital financial data, and death certificate information from Pennsylvania.
Data Collection. We used 370,017 hospital episodes with one of four conditions identified by the Agency for Healthcare Research and Quality as inpatient quality indicators were extracted.
Principal Findings. The average magnitude of Medicare payment reduction on overall net revenues was estimated at 1.8 percent for hospitals with low BBA impact and 3.6 percent for hospitals with a high impact in 1998, worsening to 2 and 4.8 percent, respectively, by 2001. Operating margins decreased significantly over the time period for all hospitals ( p <.05). While unadjusted mortality rates demonstrated a disproportionate rise in mortality for patients from high impact hospitals from 1997 to 2000, adjusted analyses show no consistent, significant difference in the rate of change in mortality between high-impact and low-impact hospitals ( p =.04–.94). Similarly, uninsured patients did not experience greater increases in mortality in high-impact hospitals relative to low-impact hospitals.
Conclusions. An analysis of hospitalizations in the Commonwealth of Pennsylvania did not find an adverse impact of increased financial strain from the BBA on patient mortality either among all patients or among the uninsured. 相似文献
2.
Bruce G. Haffty M.D. Peter L. Perrotta M.D. † Barbara Ward M.D. ‡ Meena Moran M.D. Malcolm Beinfield M.D. ‡ Charles McKhann M.D. ‡ Diana Fischer Ph.D. Darryl Carter M.D. † 《The breast journal》1997,3(1):7-14
Abstract: Between 1970 and 1990, 1,008 patients with early-stage breast cancer were treated by conservative surgery without axillary dissection followed by radiation therapy to the intact breast in the Department of Therapeutic Radiology at Yale-New Haven Hospital. The patient population, broken down by histologic subtype, was as follows: 761 patients presented with infiltrating ductal carcinoma, 70 patients with pure intraductal, 38 intraductal with focal invasion, 54 infiltrating lobular, 21 tubular, 17 medullary, 16 mucinous, and 29 with other various histologic subtypes. Patients were followed on a regular basis by the referring physicians and radiation oncologists. Diagnostic studies for distant metastases were performed as clinically indicated. Annual mammography was a routine component of the follow-up program. As of 3/96, with a median follow-up of 10.5 years, 83 patients developed an ipsilateral breast tumor recurrence, and 109 patients developed distant metastases resulting in an overall 10-year breast recurrence-free rate of 84%, and a 10-year distant metastasis-free rate of 78%. There were significant differences in clinical stage, pathological nodal involvement, and administration of systemic therapy between various histologic subtypes. As expected, those patients with histologies of low metastatic potential (such as intraductal, tubular, and mucinous) had significantly superior distant recurrence-free survival rates. With respect to breast relapse rates, there were no statistically significant differences in the 5- and 10-year breast recurrence-free rates between any of the histologic subtypes. Patients with intraductal carcinoma with or without focal invasion had similar breast relapse rates as those with other histologic subtypes. Patients with lobular carcinoma in situ as a histologic component also had a similar overall breast relapse-free recurrence rate. In conclusion, long-term follow-up of conservatively treated breast cancer patients demonstrates no significant differences in ipsilateral breast tumor recurrence rates between various histologic subtypes. There are no histologies which had a statistically significantly higher breast-relapse rate than infiltrating ductal carcinomas and therefore no primary histologic subtype represents a relative contraindication to breast conservation therapy. 相似文献
3.
Germline mutations of the Apc tumor suppressor gene result in increased risk for gastrointestinal carcinogenesis. The Apc1638N [+/-] mouse exhibits accelerated gastrointestinal carcinogenesis that is modifiable by select pharmacological and dietary agents. Experiments in the present study were conducted on a subculturable epithelial 1638NCOL cell line established from histologically normal colon of Apc1638N [+/-] mouse to examine the effects of selected chemopreventive agents that differ in their mechanism of action. Extent of growth arrest, number of cell population doublings, cell cycle progression and aneuploid G0/G1: S + G2/M ratio represented the quantitative endpoints for the susceptibility and efficacy of chemopreventive agents. Treatment of exponentially growing 1638NCOL cells with maximum cytostatic dose of 9cisRA, DFMO or SUL (100 microM) produced a 60-70% growth arrest, that with TAM and AMF (10 microM) produced a 20-40% growth arrest, while that with OLT (100 microM) produced a 25% growth arrest. This response was associated with corresponding decrease in the number of cell population doubling. 9cisRA, SUL or AMF increased the aneuploid G0/G1: S + G2/M ratio by inducing G1 checkpoint arrest, while DFMO, TAM and OLT decreased the ratio by inducing G2 checkpoint arrest. Thus, cell cycle phase-dependent susceptibility of the Apc [+/-] 1638NCOL cell line to mechanistically distinct chemopreventive agents validates a novel colon epithelial cell culture model for mechanistic, preventive or therapeutic studies on Apc regulated colon carcinogenesis. 相似文献
4.
Vinod Chandran 《Expert Review of Clinical Immunology》2020,16(5):471-478
ABSTRACT
Introduction
Biomarkers may help influence long-term outcomes of psoriatic disease by improving the objective assessment of the presence and severity of psoriatic arthritis (PsA) and by guiding treatment selection. However, there are no validated biomarkers for PsA. 相似文献5.
Three fowl adenovirus 4 (FAV4) isolates from chicken and one from quail, all from Tamil Nadu, India were analyzed. The L1 loop variable region of hexon gene of these isolates was amplified by PCR and sequenced. The nucleotide sequences (442 bp) and deduced amino acid sequences of the four isolates were compared with those of other isolates of FAV4. The nucleotide sequences of the four isolates had a 98% homology with other Indian isolates and a 96% homology with Belgian and Russian isolates. The amino acid sequences of the four Indian isolates had a more than 98% homology with other Indian isolates and a more than 92% homology with Belgian and Russian isolates. Hence, the variable of L1 loop region of hexon gene was found to be highly homologous in all the FAV4 isolates tested both at nucleotide and amino acid level. 相似文献
6.
Haemophilus influenzae type b (Hib) is responsible for significant morbidity and mortality worldwide, particularly in children under 5 years of age. In countries where the Hib conjugate vaccine is not routinely used, Hib is a leading cause of childhood pneumonia and meningitis. Routine use of the Hib conjugate vaccines has resulted in a remarkable decline in Hib disease in developed and developing countries. However, Hib conjugate vaccines are not routinely available in most developing countries, many of which have high burdens of Hib disease. This review outlines the pathogenesis and epidemiology of Hib disease, and the various options for prevention. 相似文献
7.
8.
Tan JA George E Tan KL Chow T Tan PC Hassan J Chia P Subramanium R Chandran R Yap SF 《Clinical and experimental medicine》2004,4(3):142-147
Abstract
β-thalassemia is the most-common genetic disorder of hemoglobin synthesis in Malaysia, and about 4.5% of the population are
heterozygous carriers of the disorder. Prenatal diagnosis was performed for 96 couples using the Amplification Refractory
Mutation System and Gap-Polymerase Chain Reaction. We identified 17 β-globin defects-initiation codon for translation (T-G),
-29 (A-G), -28 (A-G), CAP +1 (A-C), CD 8/9 (+G), CD 15 (G-A), CD 17 (A-T), CD 19 (A-G), Hb E (G-A), IVS1-1 (G-T), IVS1-5 (G-C),
CD 41/42 (-CTTT), CD 71–72 (+A), IVS2-654 (CT), poly A(A-G), 100-kb Gγ(Aγδβ)° and 45-kb Filipino deletions. The 192 β-alleles studied comprised Chinese (151 patients), Malay (21), Orang Asli from
East Malaysia (15), Filipino (1), Indian (1), Indonesian Chinese (2), and Thai (1). In the Chinese, 2 β-globin defects at
CD 41/42 and IVS2-654 were responsible for 74% of β-thalassemia. β-mutations at CD 19, IVS1-1 (G-T), IVS1-5, poly A, and hemoglobin
E caused 76% of the hemoglobin disorders in the Malays. The Filipino 45-kb deletion caused 73.3% of bthalassemia in the Orang
Asli. Using genomic sequencing, the rare Chinese β-mutation at CD 43 (G-T) was confirmed in 2 Chinese, and the Mediterranean
mutation IVS1-1 (G-A) was observed in a Malay β-thalassemia carrier. The β-globin mutations confirmed in this prenatal diagnosis
study were heterogenous and 65 (68%) couples showed a different globin defect from each other. The use of specific molecular
protocols has allowed rapid and successful prenatal diagnosis of β-thalassemia in Malaysia. 相似文献
9.
Differential viral protein expression in Kaposi's sarcoma-associated herpesvirus-infected diseases: Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Parravicini C Chandran B Corbellino M Berti E Paulli M Moore PS Chang Y 《The American journal of pathology》2000,156(3):743-749
10.
Human herpesvirus 6 (HHV-6) prototype isolate GS is a newly identified lymphotropic herpesvirus and several subsequent herpes isolates were recognized as HHV-6 by their hybridization to a HHV-6(GS) DNA probe pZVH14. DNA restriction analysis and in vitro tropism studies show that HHV-6 isolates can be divided into two groups, designated group A and group B. Antigenic relationships among 15 HHV-6 isolates belonging to these two groups were examined using rabbit antibodies against HHV-6(GS) infected cells, 11 monoclonal antibodies against three glycoproteins and four non-glycoproteins of HHV-6(GS), and sera from 136 healthy adults. More than 20 polypeptides from all these isolates were immunoprecipitated by rabbit polyclonal antibodies against HHV-6(GS) infected cells. Reactivities of monoclonal antibodies segregated these isolates into the same two groups. Group A contains HHV-6(GS), HHV-6(U1102) from a Ugandan acquired immunodeficiency syndrome (AIDS) patient, and nine other HHV-6 isolates from various disorders. HHV-6(Z-29) from a Zairian AIDS patient, HHV-6(SF) isolated from the saliva of a human immunodeficiency virus (HIV)-infected individual, HHV-6(OK) from a child with exanthem subitum, and HHV-6(DC) from a leukopenia patient are in group B. Eighty-one percent of the sera showed similar antibody titer in immunofluorescence assay with group A HHV-6(GS) and group B HHV-6(Z-29) infected cells and 19% of the sera showed two- to four-fold antibody titer differences. The mobilities of many of the polypeptides immunoprecipitated from group A HHV-6(GS) and group B HHV-6(Z-29) infected cells were different and sera showed differences in the quantities and nature of polypeptides immunoprecipitated.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献