全文获取类型
收费全文 | 883篇 |
免费 | 65篇 |
国内免费 | 63篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 47篇 |
妇产科学 | 2篇 |
基础医学 | 89篇 |
口腔科学 | 25篇 |
临床医学 | 75篇 |
内科学 | 201篇 |
皮肤病学 | 24篇 |
神经病学 | 18篇 |
特种医学 | 257篇 |
外科学 | 35篇 |
综合类 | 56篇 |
预防医学 | 30篇 |
眼科学 | 5篇 |
药学 | 123篇 |
肿瘤学 | 22篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 11篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 17篇 |
2013年 | 28篇 |
2012年 | 4篇 |
2011年 | 11篇 |
2010年 | 21篇 |
2009年 | 29篇 |
2008年 | 9篇 |
2007年 | 47篇 |
2006年 | 19篇 |
2005年 | 29篇 |
2004年 | 11篇 |
2003年 | 17篇 |
2002年 | 14篇 |
2001年 | 26篇 |
2000年 | 12篇 |
1999年 | 24篇 |
1998年 | 59篇 |
1997年 | 63篇 |
1996年 | 57篇 |
1995年 | 58篇 |
1994年 | 34篇 |
1993年 | 42篇 |
1992年 | 14篇 |
1991年 | 18篇 |
1990年 | 20篇 |
1989年 | 47篇 |
1988年 | 36篇 |
1987年 | 32篇 |
1986年 | 17篇 |
1985年 | 21篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 15篇 |
1981年 | 18篇 |
1980年 | 19篇 |
1979年 | 11篇 |
1978年 | 5篇 |
1977年 | 14篇 |
1976年 | 10篇 |
1975年 | 7篇 |
排序方式: 共有1011条查询结果,搜索用时 812 毫秒
991.
Antiphospholipid antibodies and venous thromboembolism 总被引:14,自引:2,他引:14
Ginsberg JS; Wells PS; Brill-Edwards P; Donovan D; Moffatt K; Johnston M; Stevens P; Hirsh J 《Blood》1995,86(10):3685-3691
The clinical relevance of antiphospholipid antibodies (APLA) in patients without systemic lupus erythematosus who have venous thromboembolism (VTE) in unknown. Limited evidence suggests that there is an association between the presence of APLA and both initial and recurrent episodes of VTE and that patients with APLA and VTE are resistant to warfarin therapy. Unselected patients with a first episode of clinically suspected deep vein thrombosis or pulmonary embolism were evaluated with objective tests for VTE and with laboratory tests for APLA; the latter included tests for the lupus anticoagulant (LA) and anticardiolipin antibodies (ACLA). Patients with VTE were treated with anticoagulant therapy and observed during and after discontinuation of anticoagulants for symptomatic recurrence of VTE. There was a strong association between LA and VTE (odds ratio, 9.4; 95% confidence interval [CI], 2.1 to 46.2) and 9 to 65 (14%; 95% CI, 7% to 25%) patients with VTE had LA. There was no association between the presence of ACLA and VTE (odds ratio, 0.7; 95%CI, 0.3 to 1.7) because of the high frequency of positive ACLA assays in patients without VTE. None of the 16 patients with VTE and APLA developed recurrent VTE while receiving warfarin therapy. There was no difference in rates of recurrent VTE in patients with or without APLA after anticoagulant therapy was discontinued. The strong association between LA and VTE suggests that testing for LA in patients with VTE is useful. The measurement of ACLA in patients with VTE has no clinical usefulness because the results are abnormal in a high proportion of patients without VTE. Although the presence of APLA in patients with VTE was not associated with resistance to a conventional intensity of warfarin or an increased risk of recurrent VTE after discontinuation of warfarin, a larger study should address these issues in a subgroup of patients with VTE and LA. 相似文献
992.
Biochemical and functional consequences of dissociation of the platelet membrane glycoprotein IIb-IIIa complex 总被引:10,自引:1,他引:10
The platelet membrane glycoproteins, IIb and IIIa, form a Ca2+- dependent heterodimer complex that functions as the fibrinogen receptor in activated platelets to mediate platelet aggregation. Little is known about factors that affect the IIb-IIIa complex within the platelet membrane. It has been observed that platelets incubated with ethylene glycol tetra-acetic acid (EGTA) at 37 degrees C are unable to aggregate or to bind monoclonal antibodies specific for the IIb-IIIa complex. To determine whether this is due to a dissociation of IIb from IIIa, we developed a method for quantitating the complex on nondenaturing, polyacrylamide gradient gels. Platelets were surface-labeled with 125I and then solubilized and electrophoresed in 0.2% Triton and 10 mmol/L CHAPS. Under these conditions and in the presence of 1 mmol/L Ca2+, glycoproteins IIb and IIIa migrated on the gels as a discrete band at Rf = 0.33. Protein that was eluted from this band bound to an immunoaffinity column specific for the IIb-IIIa complex. In contrast, when the IIb-IIIa complex was solubilized and then dissociated with EGTA, the discrete band at Rf = 0.33 was no longer present, and IIb and IIIa were now found in a broad band at Rf = 0.45 to 0.50. To study IIb and IIIa within the surface membrane, the 125I-labeled platelets were first incubated with 0.5 mmol/L EGTA (1 nmol/L free Ca2+) at 22 degrees C and then solubilized in the absence of EGTA. The IIb and IIIa from these platelets migrated at Rf = 0.33, indicating the presence of the intact IIb-IIIa complex. In contrast, when the platelets were incubated at 37 degrees C for one hour with the EGTA, the discrete band at Rf = 0.33 representing the IIb-IIIa complex gradually disappeared. This phenomenon could not be reversed by adding Ca2+ back to the platelets before solubilization and electrophoresis. This loss of the IIb-IIIa complex from intact platelets was accompanied by (a) a progressive and irreversible decrease in adenosine diphosphate (ADP)-induced platelet aggregation and (b) decreased binding of a complex-dependent monoclonal antibody to the platelets. These studies demonstrate that when platelets are exposed to low Ca2+ at 37 degrees C, the IIb-IIIa heterodimer complexes in their surface membranes are irreversibly disrupted. Because intact IIb-IIIa complexes are required for platelet aggregation, the loss of these complexes may account for the failure of these platelets to aggregate in response to ADP. 相似文献
993.
Loss of idealism or realistic optimism? A cross‐sectional analysis of dental hygiene students’ and registered dental hygienists’ professional identity perceptions
下载免费PDF全文
![点击此处可从《International journal of dental hygiene》网站下载免费的PDF全文](/ch/ext_images/free.gif)
994.
EL Koster JS Dashe DD McIntire RM Ramus 《The journal of maternal-fetal & neonatal medicine》2013,26(1):3-7
Objective: To evaluate the relationship between maternal serum α-fetoprotein (MSAFP) and the risk of persistent placenta previa.Methods: We conducted a retrospective cohort study of singleton pregnancies with sonographic evidence of placenta previa at 15?–?20 weeks' gestation, between October 1991 and August 2000. Only pregnancies with MSAFP determination at 15?–?20 weeks' gestation and non-anomalous live-born infants ??24 weeks' gestation were included. Pregnancies in which Cesarean delivery was performed for placenta previa were considered persistent; this was the primary outcome.Results: Of 275 women with previa at 15?–?20 weeks' gestation, 33 (12%) had previa at delivery. Trend analysis revealed a greater likelihood of persistent previa with increasing MSAFP values (p?=?0.01). Mid-trimester MSAFP <?1 multiple of the median (MoM) was associated with a decreased incidence of persistence of 4%, significantly less than the risk at ??1 MoM (16%; p?=?0.01).Conclusions: There is an association between increasing MSAFP values and greater likelihood of persistent placenta previa. An MSAFP value <?1 MoM is associated with a reduction in the risk of persistence of previa to delivery. 相似文献
995.
Comparison of cytopathic changes in oral hairy leukoplakia with in situ hybridization for EBV DNA 总被引:1,自引:0,他引:1
JS Greenspan YG de Souza JA Regezi TE Daniels D Greenspan LA MacPhail JF Hilton 《Oral diseases》1998,4(2):95-99
OBJECTIVE: It has been observed that the cytopathic changes in hairy leukoplakia (HL) correlate with ultra-structural evidence of intra-keratinocyte herpes-type viral particles. In situ hybridization is considered to be the definitive confirmation of Epstein-Barr virus (EBV)-induced HL. This study evaluated the consistency of histopathological findings, which many believe to be diagnostic, with in situ hybridization for EBV-DNA in 60 patients with lesions clinically suggestive of HL.
MATERIALS AND METHODS: Hematoxylin and eosin (H&E)-stained sections were reviewed independently by three oral pathologists who did not know the hybridization results. The presence in keratinocytes of nuclear inclusions and/or homogenization, believed to be specific for EBV in these lesions, was used as an indicator for infection. Cytoplasmic changes were evaluated separately.
RESULTS: With in situ hybridization, 48 cases were positive and 12 were negative. When the two methods were compared, pathologist concurrence ranged from 83% to 92%. False negatives ranged from 6% to 19%, and false positives ranged from 8% to 25%. Cytoplasmic ballooning, homogenization, and perinuclear clearing were evident in all cases of hybridization-confirmed HL; however, these changes were also noted in 75% (9/12) of the cases with negative hybridization results. Most confirmed HL cases exhibited both nuclear homogenization and inclusions, although the former was more consistently seen.
CONCLUSION: Cytoplasmic changes did not agree well with EBV-DNA hybridization results, whereas nuclear changes demonstrated good, but not complete, agreement. In appropriate clinical settings, the finding of nuclear inclusions and/or homogenization may be of diagnostic value. However, because the potential for false positives and negatives is high, H&E cytopathology should not be used as a substitute for in situ hybridization in the definitive diagnosis of oral hairy leukoplakia. 相似文献
MATERIALS AND METHODS: Hematoxylin and eosin (H&E)-stained sections were reviewed independently by three oral pathologists who did not know the hybridization results. The presence in keratinocytes of nuclear inclusions and/or homogenization, believed to be specific for EBV in these lesions, was used as an indicator for infection. Cytoplasmic changes were evaluated separately.
RESULTS: With in situ hybridization, 48 cases were positive and 12 were negative. When the two methods were compared, pathologist concurrence ranged from 83% to 92%. False negatives ranged from 6% to 19%, and false positives ranged from 8% to 25%. Cytoplasmic ballooning, homogenization, and perinuclear clearing were evident in all cases of hybridization-confirmed HL; however, these changes were also noted in 75% (9/12) of the cases with negative hybridization results. Most confirmed HL cases exhibited both nuclear homogenization and inclusions, although the former was more consistently seen.
CONCLUSION: Cytoplasmic changes did not agree well with EBV-DNA hybridization results, whereas nuclear changes demonstrated good, but not complete, agreement. In appropriate clinical settings, the finding of nuclear inclusions and/or homogenization may be of diagnostic value. However, because the potential for false positives and negatives is high, H&E cytopathology should not be used as a substitute for in situ hybridization in the definitive diagnosis of oral hairy leukoplakia. 相似文献
996.
997.
998.
An intimate relationship between thyroid hormones and carbohydrate metabolism has long been recognised and oral glucose load produces flat glucose tolerance curve in patients with primary hypothyroidism. Although delayed glucose absorption was proposed to explain flat glucose tolerance curve exact mechanism remains to be elucidated. Hence this study was undertaken to assess glucose and insulin response to OGTT and IVGTT in 25 freshly detected cases of hypothyroidism and 25 healthy control. The cases were matched for sex, age, BMI, and waist hip ratio with controls. Cases and controls with past or family history of obesity, diabetes mellitus, or hypertension were excluded from study. The biochemical profile of the cases and controls was also comparable except for haemoglobin (11.2±0.31 vs 12.9±0.22 gm/dl)(p=0.0004). Serum cholesterol and triglyceride levels were higher in the cases but difference was not statistically significant Fasting plasma glucose level was significantly lower in hypothyroid patients (78±2.2 vs88±4.4 mg/dl, p=0.049). The oral glucose tolerance curve was flat with plasma glucose levels significantly lower at 30 minutes. The insulin levels during OGTT were found to be higher in the cases at all stages. There was loss of first phase insulin response to the glucose load during the IVGTT, which was blunted at all stages and the difference was statistically significant at 0 and 3 minutes. Loss of first phase insulin response to IV glucose suggests that there is evidence of beta-cell dysfunction. Patients with hypothyroidism were more insulin sensitive than control and insulin secretion was comparable with controls. Therefore flat glucose tolerance curve can be explained by absence of insulin priming effect leading to decreased glucose absorption followed by increased glucose disposal because of higher insulin levels following OGTT and increased glucose disposal caused by increased insulin sensitivity.KEY WORDS: Beta-cell function, Hypothyroidism, Insulin resistance, Insulin sensitivity 相似文献
999.
Manuel JK Austin JL Miller WR McCrady BS Tonigan JS Meyers RJ Smith JE Bogenschutz MP 《Journal of substance abuse treatment》2012,43(1):129-136
In a randomized clinical pilot study, 40 concerned significant others (CSOs) of treatment-refusing alcohol- and drug-using individuals were randomized to either Community Reinforcement and Family Training (CRAFT) conducted in a group format (Group CRAFT) or a Self-Directed CRAFT condition. Although results indicated no significant between-group difference in engaging treatment-refusing substance-using individuals (referred to as identified patients or IPs) into treatment, the engagement rate in Group CRAFT was similar to rates previously reported with individual CRAFT. For the intent-to-treat analysis, 60% of Group CRAFT CSOs engaged their loved one into treatment, as compared with 40% in Self-Directed CRAFT. Of CSOs in the Group condition who received at least one session of group therapy, 71% engaged their IP into treatment. CSOs in both conditions reported improvements in family cohesion and conflict at the 3- and 6-month follow-up, replicating prior CRAFT findings. 相似文献
1000.
A Samaranayake MY Chen J McNeil TRH Read JS Hocking CS Bradshaw CK Fairley 《HIV medicine》2010,11(7):427-431