全文获取类型
收费全文 | 4291篇 |
免费 | 340篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 22篇 |
儿科学 | 116篇 |
妇产科学 | 189篇 |
基础医学 | 605篇 |
口腔科学 | 98篇 |
临床医学 | 373篇 |
内科学 | 961篇 |
皮肤病学 | 75篇 |
神经病学 | 367篇 |
特种医学 | 302篇 |
外科学 | 599篇 |
综合类 | 41篇 |
一般理论 | 2篇 |
预防医学 | 331篇 |
眼科学 | 66篇 |
药学 | 192篇 |
中国医学 | 4篇 |
肿瘤学 | 299篇 |
出版年
2022年 | 49篇 |
2021年 | 108篇 |
2020年 | 65篇 |
2019年 | 83篇 |
2018年 | 107篇 |
2017年 | 85篇 |
2016年 | 90篇 |
2015年 | 107篇 |
2014年 | 136篇 |
2013年 | 169篇 |
2012年 | 267篇 |
2011年 | 194篇 |
2010年 | 164篇 |
2009年 | 114篇 |
2008年 | 161篇 |
2007年 | 177篇 |
2006年 | 152篇 |
2005年 | 145篇 |
2004年 | 137篇 |
2003年 | 146篇 |
2002年 | 128篇 |
2001年 | 117篇 |
2000年 | 116篇 |
1999年 | 109篇 |
1998年 | 81篇 |
1997年 | 89篇 |
1996年 | 81篇 |
1995年 | 66篇 |
1994年 | 72篇 |
1993年 | 60篇 |
1992年 | 82篇 |
1991年 | 82篇 |
1990年 | 75篇 |
1989年 | 81篇 |
1988年 | 73篇 |
1987年 | 68篇 |
1986年 | 78篇 |
1985年 | 66篇 |
1984年 | 35篇 |
1983年 | 36篇 |
1982年 | 30篇 |
1980年 | 21篇 |
1979年 | 25篇 |
1978年 | 31篇 |
1977年 | 28篇 |
1976年 | 24篇 |
1975年 | 20篇 |
1973年 | 23篇 |
1971年 | 24篇 |
1969年 | 27篇 |
排序方式: 共有4642条查询结果,搜索用时 15 毫秒
21.
Ramirez Claudia C. MD Ma Fangchao MD PhD Federman Daniel G. MD † Kirsner Robert S. MD PhD ‡§ 《Dermatologic surgery》2005,31(7):748-753
Background Results from in vitro and animal studies suggest that cyclooxygenase (COX) inhibitors may reduce the risk of melanoma, but among humans, the evidence remains limited.
Objective In a pilot retrospective cohort, to determine the relationship between the use of COX inhibitors and the incidence, recurrence, and metastases of melanoma in high-risk patients.
Methods Reviewing computerized records at the Miami Veterans Affairs Medical Center, we retrospectively examined the association between COX inhibitor use and melanoma incidence, recurrence, and metastases in high-risk subjects: white subjects previously diagnosed with melanoma (1996–2003). We evaluated three potential outcomes: new melanoma diagnosis, recurrence of a previous melanoma, and melanoma metastasis.
Results Eighty-three subjects with melanoma were included. There was one metastasis among 28 subjects prescribed COX inhibitors, whereas four new melanomas (7.3%), two melanoma recurrences, and six metastases (10.9%) occurred among 55 patients not prescribed COX inhibitors. Although no individual outcomes measures reached statistical significance, combining the three measures, these were significantly lower in users of COX inhibitors compared with nonusers (1 vs 12; p = .05 ). After adjustment for age and tumor depth of invasion, COX inhibitor users had significantly lower rates of melanoma outcome measures (odds ratio 0.08; 95% confidence interval 0.01–0.77; p = .03 ).
Conclusion Potential exists for chemoprevention of melanoma among high-risk patients. 相似文献
Objective In a pilot retrospective cohort, to determine the relationship between the use of COX inhibitors and the incidence, recurrence, and metastases of melanoma in high-risk patients.
Methods Reviewing computerized records at the Miami Veterans Affairs Medical Center, we retrospectively examined the association between COX inhibitor use and melanoma incidence, recurrence, and metastases in high-risk subjects: white subjects previously diagnosed with melanoma (1996–2003). We evaluated three potential outcomes: new melanoma diagnosis, recurrence of a previous melanoma, and melanoma metastasis.
Results Eighty-three subjects with melanoma were included. There was one metastasis among 28 subjects prescribed COX inhibitors, whereas four new melanomas (7.3%), two melanoma recurrences, and six metastases (10.9%) occurred among 55 patients not prescribed COX inhibitors. Although no individual outcomes measures reached statistical significance, combining the three measures, these were significantly lower in users of COX inhibitors compared with nonusers (1 vs 12; p = .05 ). After adjustment for age and tumor depth of invasion, COX inhibitor users had significantly lower rates of melanoma outcome measures (odds ratio 0.08; 95% confidence interval 0.01–0.77; p = .03 ).
Conclusion Potential exists for chemoprevention of melanoma among high-risk patients. 相似文献
22.
Julio A. Ramirez 《Disease Management & Health Outcomes》2003,11(1):33-43
Several national and international organizations have developed and published guidelines for the treatment of patients with community-acquired pneumonia (CAP). Guidelines from Europe, the US, Canada and Latin America classify patients in different groups based on the severity of pneumonia, site of care and presence of risk factors for resistant organisms. The initial antibacterial therapy is designed to cover only the likely organisms able to infect a particular group of patients. An evaluation of current guidelines indicates that there are significant similarities in regard to classification of patients and initial antibacterial therapy. One objective of this review is to present the clinician with a practical approach to antibacterial selection based on current published guidelines for CAP.Although most of the care recommended in guidelines is evidence-based and associated with better clinical outcomes and/or decreased healthcare cost, there is still a significant gap between recommended care and actual care of patients with CAP. Dissemination of guidelines at the local level has proved to have a minimal effect in changing local practices. To bring the local care of patients with CAP closer to the care recommended in guidelines, it is necessary to have an appropriate plan for guideline implementation. This review provides the clinician and other healthcare decision-makers with a methodology for implementation of national guidelines at the local hospital level. 相似文献
23.
Introduction : Hypertrophic scar is a devastating sequel to burns and other tangential skin injuries. It follows deep dermal injuries and does not occur after superficial injuries. Nitric oxide (NO) plays many important roles in wound healing from inflammation to scar remodeling. Studies have shown that expression of nitric oxide synthase and nitric oxide production are decreased in human hypertrophic scar. However little is known about NO involvement in the early stages of hypertrophic scarring, because of the lack of an animal model. It was recently reported that the female red Duroc pig (FRDP) makes thick scar, which is similar to human hypertrophic scar. We hypothesized that NO production in wounds on the female, red Duroc pig is similar to that of human hypertrophic scar and that NO involvement in deep wounds is different from that in superficial wounds. Methods : Superficial (0.015” to 0.030”) and deep (0.045” to 0.060”) wounds were created on the backs of four FRDPs. Biopsies were collected at weeks 1.5, 4, 8 and 21 post wounding including samples of uninjured skin. Nitric oxide levels were measured with the Griess reaction assay and normalized with tissue protein level. Results : Superficial wounds healed with an invisible scar whereas the deep wounds healed with scar resembling mild hypertrophic scar. The thickness of the scars from the deep wounds was significantly greater than uninjured skin and healed superficial wounds (p < 0.01). NO levels were increased at 1.5 weeks in deep wounds compared to superficial wounds and uninjured skin (p < 0.05). At 8 weeks, NO levels in deep wounds had returned to the level of uninjured tissue and superficial wounds. By 21 weeks, NO levels had decreased significantly when compared to superficial wounds (p < 0.01). There were no differences in NO levels between uninjured skin and superficial wounds at any time point (p > 0.05). Conclusions : NO production is similar in late, deep wounds on the female, red Duroc pig to that reported in the literature for human hypertrophic scar further validating this animal model. NO production is quite different after deep wounds as compared to superficial wounds in the FRDP. Early elevation in nitric oxide production might account for excessive inflammation in deep wounds that become thick scars in the FRDP. Nitric oxide regulators and effects at early stages of scar formation should be elucidated further and the FRDP appears to be a useful model. 相似文献
24.
25.
Summary— Experiments were designed to determine whether or not indapamide, an antihypertensive agent with vasodilator properties, inhibits endothelium-dependent contractions. Rings of aortae with and without endothelium from spontaneously hypertensive rats (SHR) were suspended in conventional organ chambers for the measurement of isometric force. Acetylcholine and adenosine diphosphate-β-S in the presence of a nitric oxide synthase inhibitor, caused endothelium-dependent contractions, which were inhibited by indapamide. The compound (10−4 M) also slightly reduced the contractions of rings without endothelium evoked by U-46,619, which activates thromboxane-endoperoxide receptors. These results demonstrate that indapamide inhibits endothelium-dependent contractions in the SHR aorta, and suggest that the inhibition is due, at least in part, to the action of the drug on the hypertensive vascular smooth muscle. 相似文献
26.
Cranial sutures and craniometric points detected on MRI 总被引:2,自引:0,他引:2
Cotton F Rozzi FR Vallee B Pachai C Hermier M Guihard-Costa AM Froment JC 《Surgical and radiologic anatomy : SRA》2005,27(1):64-70
The main goal of the study was to determine on MRI the cranial sutures, the craniometric points and craniometric measurements, and to correlate these results with classical anthropometric measurements. For this purpose, we reviewed 150 cerebral MRI examinations considered as normal (Caucasian population aged 2049 years). For each examination we individualized 11 craniometric landmarks (Glabella, Bregma, Lambda, Opisthocranion, Opisthion, Basion, Inion, Porion, Infra-orbital, Eurion) and three measurements. Measurements were also calculated independently on 498 dry crania (Microscribe 3-DX digitizer). To validate the MRI procedure, we measured four dry crania by MRI and with compass or digital caliper gauges. Cranial sutures always appeared without signal (black), whatever the MRI sequence used, and they are better visualized with a 5 mm slice thickness (compact bone overlapping). Slice dynamic analysis and multiplanar reformatting allowed the detection of all craniometric points, some of these being more difficult to detect than others (Porion, Infra-orbital). The measurements determined by these points were as follows: VertexBasion height=135.66±6.56 mm; EurionEurion width=141.17±5.19 mm; GlabellaOpisthocranion length=181.94±6.40 mm. On the midline T1-weighted sagittal image, all median craniometric landmarks can be individualized and the GlabellaOpisthocranion length, VertexBasion height and parenchyma indices can be calculated. Craniometric points and measurements between these points can be estimated with a standard cerebral MRI examination, with results that are similar to anthropometric data. 相似文献
27.
Peritoneal fluid concentrations of interleukin-8 in women with endometriosis: relationship to stage of disease 总被引:7,自引:10,他引:7
Gazvani MR; Christmas S; Quenby S; Kirwan J; Johnson PM; Kingsland CR 《Human reproduction (Oxford, England)》1998,13(7):1957-1961
There is increasing evidence that immunological mechanisms play a role in
the pathogenesis and pathophysiology of endometriosis. It was therefore of
interest to study interleukin-8 (IL-8), a chemokine, in the peritoneal
fluid and peripheral blood of women undergoing laparoscopic procedures. The
presence and concentrations of IL-8 in relation to endometriosis,
infertility and abdominal pain were evaluated. Samples of peritoneal fluid
(n = 49) and peripheral blood (n = 50) were obtained from 50 consecutive
patients undergoing laparoscopic surgery for various gynaecological
indications (abdominal pain, infertility, sterilization). IL-8 was present
in the peritoneal fluid of most women (87%). The concentration of IL-8 in
the peritoneal fluid was higher in women with endometriosis compared to
women without (P = 0.02). This difference was more pronounced in early
(stage 1) endometriosis (P = 0.001). IL-8 concentrations in the peritoneal
fluid were also higher in women with early endometriosis compared to women
with later stages of the disease (P = 0.003). Peripheral blood
concentrations did not correlate with peritoneal fluid concentrations of
IL-8 and/or the presence of endometriosis. We conclude that IL-8 is an
important factor that may contribute to the pathogenesis of endometriosis
possibly by promoting neovascularization. This information can be a guide
in the development of new therapeutic approaches for the treatment of
endometriosis.
相似文献
28.
29.
Giuseppe A. Ramirez Valentina Canti Stefania Del Rosso Roberta Erra Lucia Moiola Marco Magnoni 《Autoimmunity》2020,53(1):21-27
AbstractBackground: Systemic lupus erythematosus (SLE) is associated with a constellation of complications affecting multiple organs, including neuropsychiatric manifestations (NPSLE) and ischaemic events, leading to increased long-term morbidity. Antiphospholipid antibodies (aPL) are a major determinant of vascular inflammation and thromboembolic risk. The diagnostic role of anti-phosphatidylserine/prothrombin (aPS/PT) antibodies in this setting is incompletely defined.Aim: To verify whether aPS/PT add to diagnostics and disease stratification in patients with SLE with or without other aPL.Methods: 131 consecutive patients were studied, including 20 patients with SLE and secondary antiphospholipid syndrome (APS). aPS/PT IgG and IgM were assessed through ELISA and patients were stratified based on the presence of other aPL, on their clinical and laboratory features at time of blood sampling and on their clinical history. Synthetic indices of disease activity, chronic damage and cardiovascular risk were calculated at time of venipuncture.Results: Fifty-one (38.9%) patients with SLE had aPS/PT and 15 (11.5%) patients had aPS/PT as the only aPL (aPS/PT-only). aPS/PT-only patients had a significantly higher prevalence of NPSLE than quadruple aPL-negative patients (p?=?.007). Patients with aPS/PT were more likely to have a history of ischaemia, thrombocytopenia and Libman–Sacks’ endocarditis. The presence of aPS/PT also associated with previous accrual of at least one damage item (p?=?.043), but had limited predictive values for damage progression in the short term.Conclusion: aPS/PT antibodies provide non-redundant information that could contribute to risk assessment and stratification of patients with SLE. 相似文献
30.
Inhibition of Chlamydia pneumoniae replication in human aortic smooth muscle cells by gamma interferon-induced indoleamine 2, 3-dioxygenase activity 总被引:3,自引:0,他引:3 下载免费PDF全文
Pantoja LG Miller RD Ramirez JA Molestina RE Summersgill JT 《Infection and immunity》2000,68(11):6478-6481
Infection with Chlamydia pneumoniae, a human respiratory pathogen, has been implicated as a potential risk factor in atherosclerosis, possibly because the pathogen can exist in a persistent form similar to that described for Chlamydia trachomatis. The present study investigated whether gamma interferon (IFN-gamma) can induce indoleamine 2,3-dioxygenase (IDO) activity in aortic smooth muscle cells, leading to a marked inhibition of C. pneumoniae growth. Our data indicate a stimulation of IDO mRNA expression and dose-dependent enzymatic activity following IFN-gamma treatment. IDO-mediated increase in tryptophan catabolism resulted in a dose-dependent marked inhibition of C. pneumoniae replication. 相似文献