全文获取类型
收费全文 | 582篇 |
免费 | 36篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 9篇 |
妇产科学 | 21篇 |
基础医学 | 62篇 |
口腔科学 | 7篇 |
临床医学 | 64篇 |
内科学 | 139篇 |
皮肤病学 | 27篇 |
神经病学 | 33篇 |
特种医学 | 14篇 |
外科学 | 72篇 |
综合类 | 3篇 |
预防医学 | 52篇 |
眼科学 | 7篇 |
药学 | 52篇 |
中国医学 | 4篇 |
肿瘤学 | 52篇 |
出版年
2024年 | 1篇 |
2023年 | 15篇 |
2022年 | 17篇 |
2021年 | 38篇 |
2020年 | 17篇 |
2019年 | 35篇 |
2018年 | 31篇 |
2017年 | 20篇 |
2016年 | 24篇 |
2015年 | 15篇 |
2014年 | 27篇 |
2013年 | 35篇 |
2012年 | 54篇 |
2011年 | 53篇 |
2010年 | 22篇 |
2009年 | 18篇 |
2008年 | 38篇 |
2007年 | 32篇 |
2006年 | 25篇 |
2005年 | 24篇 |
2004年 | 16篇 |
2003年 | 17篇 |
2002年 | 20篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有620条查询结果,搜索用时 15 毫秒
1.
Discrimination of well-differentiated pulmonary adenocarcinoma from reactive bronchioloalveolar epithelium can be difficult on routine histology, especially with small biopsies. Ancillary studies to help in this distinction are desirable. p63, a p53-homologous nuclear protein, is a marker of reserve cells of the bronchus and terminal lobular unit. In this study, 33 cases of adenocarcinoma (20 open lung and 13 transbronchial/percutaneous biopsies) and 43 cases of benign lungs with fibrosis and metaplasia (22 open lung and 21 transbronchial/percutaneous biopsies) were studied for nuclear p63 expression by immunohistochemistry (Dako, Carpinteria, CA, USA). Five additional cases each of atypical adenomatous hyperplasia and adenosquamous carcinoma and three cases of squamous carcinoma (all open lung biopsies) were also stained. The diagnostic categories of benign lung conditions were usual interstitial pneumonia, parenchymal scar, cryptogenic organizing pneumonia and diffuse alveolar damage. In neoplastic cases, p63 positivity was calculated as percentage of all tumor cells examined. In areas of normal lung, p63 decorated the reserve cells of large and small airways and occasional cells of the distal lobular unit. In fibrotic reactive processes, an interrupted but distinct pattern of nuclear staining was present in all cases, with staining of basal cells of the airways as well as bronchiolar- and squamous-metaplastic epithelium (43/43, 100%). p63 immunoreactivity was less uniform in areas of acute lung injury within these cases. One adenocarcinoma and two cases of atypical adenomatous hyperplasia showed strong immunoreactivity (>80%), while three adenocarcinomas highlighted only rare tumor nuclei (<5% of tumor cells). Morphologic areas where p63 immunostaining was not helpful included the junction of normal lung and lepidic growth of adenocarcinoma, and retrograde spread of adenocarcinoma into small airways. Our results highlight the differential expression of p63 across various bronchioloalveolar lesions. Moreover, p63 may be helpful in distinguishing reactive from neoplastic glandular proliferations in the lung. 相似文献
2.
Use of antidepressant medications and the possible association with breast cancer risk. A review 总被引:1,自引:0,他引:1
BACKGROUND: Antidepressant medication use has dramatically increased over the past decade, particularly for the newer classes such as selective serotonin reuptake inhibitors. While there is no question about the usefulness of these medications, it is important to review animal and epidemiologic studies that have evaluated the association between antidepressant medication use and the risk of breast cancer. METHODS: This paper reviews the scientific literature pertaining to the prevalence of and indications for antidepressant medication use, and the possible association between antidepressant medication use and breast cancer risk. RESULTS: Antidepressant medications are most commonly indicated for depressive disorders, and are also used for other conditions (e.g., anxiety disorders, personality disorders, and pain). In addition, antidepressants may be an effective alternative to estrogen therapy for the alleviation of hot flashes among peri-/postmenopausal women. Several epidemiologic studies have reported that certain antidepressants may be associated with a slightly increased breast cancer risk; however, the literature remains inconsistent. CONCLUSIONS: The possibility of an association between certain antidepressant medications and breast cancer risk has not been excluded, although further studies are needed before the body of scientific evidence can be conclusive. Evidence to date does not support a change in the current use of antidepressant medications. 相似文献
3.
Chorneyko K Giesler R Sabatino D Ross C Lobo F Shuhaibar H Chen V Elavathil L Denardi F Ansari S Salama S LeBlanc V Norman G Sheridan B Riddell R 《American journal of clinical pathology》2002,117(5):783-790
Telepathology (TP) uses telecommunication linkages to electronically capture, store, retrieve, and transmit images to distant sites. We assessed the feasibility of a dynamic real-time TP system for light microscopic (LM) diagnosis of anatomic pathology specimens, including frozen sections. Six pathologists, in 2 separate periods, read a set of 160 retrospectively retrieved slides (80 of which were frozen sections) by TP and LM. Reading times were recorded. Diagnoses were compared with the reference diagnosis (established by a group of 5 independent pathologists) and graded on a scale of 0 to 2 (2, correct; 1, incorrect but no clinical impact; 0, incorrect with clinical impact). Overall, LM was more accurate than TP compared with the reference diagnosis (score, 1.68 vs 1.54). There was no difference in accuracy between frozen section and paraffin-embedded tissue. Intraobserver agreement ranged from 82.5% to 88.2%. The average reading time was 6.0 minutes for TP and 1.4 minutes for LM. During the study, reading time decreased for TP but not for LM. These results show that despite marginally lower accuracy and longer reading times, TP isfeasible for routine light microscopic diagnosis, including frozen sections. 相似文献
4.
Salahuddin Saira; Ookutsu Shoji; Goto Kazufumi; Nakanishi Yoshihiko; Nagata Yukihiro 《Human reproduction (Oxford, England)》1995,10(9):2382-2385
We have evaluated the effects of embryo density and the co-cultureof unfertilized (degenerating) oocytes on the development ofin-vitro fertilized (IVF) mouse embryos. In experiment 1, groupsof one, five, 10 or 20 zygotes were cultured in 20 µldrops of modified human tubal fluid (HTF) medium for 168 h at38.7°C in 5% CO2 and 95% air. As the embryo density increased,significantly (P < 0.05) higher rates of embryos reachedhatched blastocyst stage. In addition, the time required forhatching after IVF was significantly (P < 0.05) shortenedby the increase in embryo density. In experiment 2, 10 IVF zygoteswere cultured with or without 10 unfertilized (degenerating)oocytes in 20 µl drops of HTF medium. The rates of IVFembryos that developed to morula, blastocyst, expanded blastocystand hatched blastocyst stages were decreased significantly (P< 0.01) by culturing embryos with unfertilized oocytes comparedwith culturing embryos alone. In experiment 3, groups of oneor 10 IVF zygotes or 10 IVF zygotes plus 10 unfertilized oocyteswere cultured in 20 µl drops of HTF medium and the numberof cells per blastocyst was examined at 120 h after IVF. Increasingembryo density resulted in a significant (P < 0.05) increasein the number of cells per blastocyst. In contrast, the cellnumber of IVF embryos that developed to blastocyst decreasedsignificantly (P < 0.05) when they were cultured with unfertilizedoocytes. The results suggest that in-vitro development of IVFmouse embryos is enhanced by increasing embryo density and isimpaired by co-culture with unfertilized (degenerating) oocytes. 相似文献
5.
Ezer Kang Darcie A.P. Delzell Paul E. McNamara Joel Cuffey Anil Cherian Saira Matthew 《AIDS care》2016,28(4):416-422
Poor mental health functioning among persons living with HIV (PLHIV) has gained considerable attention particularly in low-income countries that disproportionately carry the global HIV/AIDS burden. Fewer studies, however, have examined the relationship between poverty indicators and mental health among PHLIV in India. Based on this cross-sectional study of 196 HIV-seropositive adults who received medical services at Shalom AIDS Project in Delhi, India, structural equation modeling and mediation analysis were employed to estimate the associations between poverty indices (household asset index, food security, unemployment, water treatment, sanitation), HIV-health factors (illness in the past 3 months, co-morbid medical conditions), and psychological distress. In the final model, ownership of fewer household assets was associated with higher levels of food insecurity, which in turn was associated with higher psychological distress. Also, the household asset index, food insecurity, and unemployment had a larger effect on psychological distress than new opportunistic infections. These findings build on increasing evidence that support concerted efforts to design, evaluate, and refine HIV mental health interventions that are mainstreamed with livelihood programming in high poverty regions in India. 相似文献
6.
7.
Emma M. Smith Danelle Fuller Hina Mahmood 《Disability and rehabilitation. Assistive technology》2018,13(6):523-526
Purpose: To determine if older adult, novice wheelchair users who drive a power wheelchair with a JoyBar control complete maneuverability tasks in less time and with less error than those who drive a power wheelchair with a standard joystick control.Materials and methods: A parallel randomized controlled trial design conducted at a medical rehabilitation and research centre with ambulatory older adults aged 60 and above (n?=?27). The intervention was the JoyBar alternative wheelchair control. The primary outcome measure was total time to complete each of the two maneuverability tasks. The secondary outcome measure was total number of errors during each of the maneuverability tasks.Results: An independent, two sampled t-test was conducted and revealed that the JoyBar group took a greater amount of time to complete both maneuverability tasks than the control group (p?.05). No significant differences (p?.05) were found in rates of error on either task between the JoyBar and joystick groups.Conclusions: Maneuverability of a powered wheelchair by novice wheelchair users was not improved through the use of the JoyBar when compared to a standard wheelchair joystick, as measured by rates of error and time to complete maneuverability tasks.
- Implications for rehabilitation
Clients who are new to powered wheelchair use may perform maneuverability tasks faster, with equivalent accuracy, using a standard joystick versus the JoyBar.
Clients who use a JoyBar may require adjustments to the programming of their wheelchair to ensure optimal performance.
Additional training may be required to achieve proficiency in maneuverability tasks with a JoyBar versus a standard joystick.
8.
Alexander G Fiks Peixin Zhang A Russell Localio Saira Khan Robert W Grundmeier Dean J Karavite Charles Bailey Evaline A Alessandrini Christopher B Forrest 《Health services research》2015,50(2):489-513
ObjectiveSubstantial investment in electronic health records (EHRs) has provided an unprecedented opportunity to use clinical decision support (CDS) to increase guideline adherence. To inform efforts to maximize adoption, we characterized the adoption of an otitis media (OM) CDS system, the impact of performance feedback on adoption, and the effects of adoption on guideline adherence.ConclusionsPerformance feedback increased CDS adoption, but additional strategies are needed to integrate CDS into primary care workflows. 相似文献
9.
K Hina H Watanabe M Ueeda N Yamada D Saito S Haraoka T Tsuji S Kusachi 《Cardiovascular research》1989,23(2):104-111
Forskolin, a diterpene, directly stimulates adenylate cyclase and also potentiates receptor mediated stimulation of this enzyme by many stimulatory agonists. We exploited the potentiating effect of forskolin to test the hypothesis that activation of adenylate cyclase contributes to myocardial reactive hyperaemia, especially by release of adenosine at the time of brief coronary occlusions. In 10 open chest dogs, intracoronary forskolin infusions which produced plasma concentrations between 0.22 and 0.34 mumol.litre-1 slightly increased coronary blood flow and had no effect on haemodynamics or myocardial metabolism. Under these conditions, though peak reactive hyperaemic flow rates were not affected, forskolin infusions reversibly potentiated repayments of flow debt by 28, 25 and 27% following coronary occlusions of 15 s, 20 s and 30 s, respectively (p less than 0.05). In another seven dogs, after observations of the effects of forskolin (0.16-0.26 mumol), 10 mumol of 8-phenyltheophylline, a potent adenosine antagonist, was infused simultaneously with forskolin into the coronary arteries. Forskolin increased debt repayments by about 23-27% following 15 s, 20 s and 30 s occlusions, but with simultaneous 8-phenyltheophylline, forskolin induced increments in the debt repayments were reduced significantly (p less than 0.05). These results indicate that adenylate cyclase contributes to myocardial reactive hyperaemia, and adenosine has a significant role as metabolic regulator of reactive hyperaemia through activation of adenylate cyclase. 相似文献
10.
Farman Ullah Hina Gul Nicolas Desneux Fazal Said Xiwu Gao Dunlun Song 《Ecotoxicology (London, England)》2020,29(4):407-416
The chive maggot, Bradysia odoriphaga (Yang and Zhang) is an economically important insect pest, affecting many key vegetables, including Chinese chive, especially in northern China. Chlorfenapyr, a halogenated pyrrole insecticide that interferes with mitochondrial oxidative phosphorylation is widely used against B. odoriphaga. In this study, we evaluated selection-induced resistance to chlorfenapyr and fitness costs in B. odoriphaga. The results showed that B. odoriphaga developed 43.32-fold resistance after continuous exposure to chlorfenapyr for over 10 consecutive generations. The life-history traits of chlorfenapyr-resistant and susceptible strains were compared using age-stage, two-sex life table approach. No significant effects were observed on the longevity and pre-adult period. However, reduction in the total pre-oviposition period (TPOP) and fecundity (eggs/female) were observed in the resistant strain. Moreover, the demographic parameters such as intrinsic rate of increase (r), net reproductive rate (R0) and finite rate of increase (λ) were also decreased significantly in the resistant strain compared to the susceptible strain. These results showed the potential of B. odoriphaga to develop resistance against chlorfenapyr under continuous selection pressure. Furthermore, there was a fitness cost linked with chlorfenapyr resistance in B. odoriphaga. We conclude that a better knowlegde on the trade-off at play between resistance degree and fitness cost could be crucial for developing further management of B. odoriphaga in China. 相似文献