首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1082篇
  免费   60篇
  国内免费   8篇
耳鼻咽喉   58篇
儿科学   75篇
妇产科学   116篇
基础医学   66篇
口腔科学   49篇
临床医学   103篇
内科学   228篇
皮肤病学   22篇
神经病学   56篇
特种医学   32篇
外科学   138篇
综合类   12篇
预防医学   27篇
眼科学   59篇
药学   48篇
肿瘤学   61篇
  2024年   1篇
  2023年   13篇
  2022年   9篇
  2021年   40篇
  2020年   16篇
  2019年   20篇
  2018年   22篇
  2017年   25篇
  2016年   62篇
  2015年   51篇
  2014年   55篇
  2013年   74篇
  2012年   116篇
  2011年   99篇
  2010年   55篇
  2009年   54篇
  2008年   83篇
  2007年   93篇
  2006年   60篇
  2005年   51篇
  2004年   43篇
  2003年   33篇
  2002年   27篇
  2001年   6篇
  2000年   6篇
  1999年   6篇
  1998年   4篇
  1997年   5篇
  1996年   6篇
  1994年   1篇
  1992年   1篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1985年   1篇
  1983年   2篇
  1981年   1篇
  1979年   1篇
  1977年   2篇
  1975年   1篇
  1972年   1篇
  1970年   1篇
排序方式: 共有1150条查询结果,搜索用时 15 毫秒
91.
It is well known that the hematocrit in microvessels with diameters smaller than 1000 microm is lower than either venous or arterial hematocrit, thereby resulting in significantly lower mean hematocrit values for vessels perfusing a given tissue (i.e., lower tissue hematocrit). The mechanisms that underlie this reduction of microvascular hematocrit include axial migration, plasma skimming and the Fahraeus Effect. It has been previously demonstrated in rats that a linear hematocrit gradient normally exists through the thickness of the left ventricular myocardium, and that this gradient is sensitive to alterations of the rheological properties of the circulating blood. The gradient is abolished if the RBC in the perfusate are rigid; fibrinogen infusions, and thus increases of both plasma viscosity and RBC aggregation, also affect this gradient. In a new series of studies, it has been observed that enhanced RBC aggregation affects the myocardial hematocrit gradient regardless of alterations of plasma viscosity. Although the exact mechanisms responsible for the myocardial hematocrit gradient, as well as its physiological significance, are not yet clearly known, it is possible to speculate that alterations in local hematocrit could adversely affect myocardial perfusion and function.  相似文献   
92.
Abnormal immune response to gliadin, genetic, and environmental factors play a role in the pathogenesis of celiac disease (CD). Non-responsiveness to hepatitis B virus (HBV) vaccination is related to genetic features. Certain human leukocyte antigen (HLA) genotypes are more prevalent among non-responders to HBV vaccination. There is also a strong relationship between CD and these HLA genotypes. This study investigates the relationship between CD and non-responsiveness to HBV vaccination, with an emphasis on genotypic co-incidence. No statistically significant difference was noted between the ages and gender of CD patients and control subjects. Baseline serum IgA, IgM, and IgG levels of all CD patients were normal. Responsiveness to HBV vaccination was observed in 17 (68%) CD patients and all (100%) control subjects (P = 0.006). In conclusion, CD should also be sought in unresponders to HBV vaccine who are not immunosuppressed.  相似文献   
93.
BACKGROUND: Serum gamma-glutamyl transferase (GGT) activity, an enzyme responsible for the extracellular catabolism of antioxidant glutathione, may directly take part in atherogenesis and evolve as a potential biochemical risk indicator of cardiovascular morbidity and mortality. An important characteristic of coronary artery ectasia (CAE) is the fact that in 85% of the cases, atherosclerotic coronary disease accompanies it. The relation between CAE and serum GGT activity has not been studied so far. Hence, we decided to investigate the serum GGT level in patients with CAE. METHODS: We measured serum GGT activity in 88 consecutive patients (48 males) with isolated CAE and 86 patients with coronary artery disease (CAD) and 84 controls. CAE was defined as being without any stenotic lesions with a visual assessment of the coronary arteries showing a luminal dilatation 1.5-fold or more of the adjacent normal coronary segments. Four subgroups were created in accordance with the CAE extension in coronary arteries. RESULTS: There were no statistically significant differences in serum GGT activity among CAE and CAD groups. Serum GGT activity was found significantly increased in patients in both CAE and CAD groups, compared with those in control group (P<0.001, P<0.001, respectively). According to the CAE severity, there were no statistically significant differences in CAE among these subgroups. CONCLUSION: We have shown for the first time that patients with CAE have higher serum GGT activity compared with controls with normal coronary angiograms. Hence, serum GGT activity can be used as a follow-up marker in patients with CAE.  相似文献   
94.
Inal S, Kelleci M. International Journal of Nursing Practice 2012; 18 : 210–219 Distracting children during blood draw: Looking through distraction cards is effective in pain relief of children during blood draw This study aims to investigate the effects of distraction method by way of looking through distraction cards/Flippits® to reduce procedural pain and anxiety during blood draw. In this method we distract attention of the children with distraction cards/Flippits®. Flippits® consist of various eye‐catching pictures and shapes. Then we asked the children questions about the cards during the blood draw procedure that he or she can only answer if he or she examines the cards carefully. This study is a prospective, randomized controlled trial. The sample consisted of 123 children of ages between 6 and 12. We randomly assigned subjects into two groups. Group 1 received no intervention, whereas Group 2 received distraction in the form of looking through distraction cards/Flippits®. Pre‐procedural and procedural anxiety was assessed using the anxiety scale from the Children's Anxiety and Pain Scales by parents' and observer's report. Procedural pain was assessed using Faces Pain Scale‐Revised by children, parent and observer reports. Results show that pre‐procedural anxiety did not differ significantly. However, the experimental group had significantly lower pain levels than the control group during the blood draw procedure. Also experimental group had significantly lower anxiety levels than the control group.  相似文献   
95.
96.
Colonic complications of Behcet''s disease due to intestinal involvement are rarely reported in the literature. Ulcers are the most frequently seen intestinal complications that cause bleeding and perforation predominantly in the ileocecal region. In this article, we report a patient with Behcet''s disease who presented with multiple perforations along the entire colon. Postoperative histopathological examination revealed multiple ulcers containing lymphocytic infiltrations in the small peripheral and submucosal venules. Intimal thickening and fresh intraluminal fibrin thrombosis were also seen in these venules.  相似文献   
97.
The use of radiotherapy (RT) with chemotherapy has improved disease free survival and control in primary central nervous system lymphoma (PCNSL). We have encountered three patients with histologically documented central nervous system lymphoma. In all patients pathological diagnosis was B-cell lymphoma. We modified IDARAM regimen to R-IDARAM to enhance and optimize chemotherapeutic components for the treatment of PCNSL. We made three changes: (i) we added rituximab 375 mg/m(2) day 1; (ii) increased dose of MTX from 2 to 3 g/m(2); and (iii) administered two additional courses of R-IDARAM after cranial RT. Following complete staging after course 2, radiotherapy was applied at a dosage of 3600-4140 cGy in conventional schedule (180 or 200 cGy per day) to whole brain (with 3600 cGy to eyes in one case because of eye involvement) and then 2 additional courses of R-IDARAM (totally four courses) chemotherapy regimen were applied. Complete remission (CR) was achieved after first two cycles of R-IDARAM in patient 1 and 3 and after four cycles in patient 2. Currently, three patients have been alive for 29, 10, 15 months respectively. Currently there is no standard treatment modality for PCNSL. Increased dosage of MTX, adding rituximab and consolidation of the IDARAM to R-IDARAM regimen may improve disease control and outcome in PCNSL patients.  相似文献   
98.
Coronary artery dissection is an uncommon but potentially serious complication in percutaneous coronary interventions. We treated a 53-year-old female patient with right coronary spasm, which was misdiagnosed as a coronary lesion. The coronary spasm resolved with nitrate administration, but proximal coronary dissection developed during angiography. It progressed anterograde and led to inferior myocardial infarction and severe hemodynamic instability due to right coronary artery occlusion. Percutaneous intervention failed, and it was determined that coronary dissection progressed retrograde, across the truncus of the aorta. Ascending aortic grafting and coronary bypass surgery were performed. The patient recovered and was discharged after 10 days. Close cardiothoracic observation is mandatory in patient evaluation and management.  相似文献   
99.
Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent inflammatory febrile attacks, abdominal, chest or joint pain, myalgia, and erysipelas-like skin lesions. Several types of vasculitis are associated with FMF such as polyarteritis nodosa and Henoch–Schönlein purpura. We aimed to determine microvascular abnormalities in FMF patients via nailfold capillaroscopy using a dermoscope. Thirty-one FMF patients were assessed; capillary enlargement, tortuosity, avascular areas and microhemmoraghes were investigated. Capillary enlargement was found in five patients and microhemorrhages in one patient. Our study supports that nailfold capillary abnormalities, which are nonspecific, can be seen in FMF patients, but more studies are needed to clarify the importance of these findings.  相似文献   
100.
Tumour necrosis factor-alpha (TNF-α) antagonist drugs have been associated with increased risk of tuberculosis (TB). Tuberculin skin test (TST) is the most frequently used tool for identification of latent TB infection. We herein aimed to analyse the effect of TNF-α antagonists on the TST responses in a prospective study. The study group consisted of 182 patients (99 female, 83 male) who received TNF-α antagonists for various rheumatic disorders. All patients were evaluated with TST along with other parameters on the day of referral and on the 12th month visit. For those patients with a response of <5 mm induration at the initial evaluation, the TST was repeated to observe the booster effect. Out of 182 patients, 87 patients (48%) had a negative (0–4 mm) and 95 (52%) had a positive (≥5 mm) TST response at initial evaluation. The TST responses were converted from negative at initial visit to positive at 1-year repeat in 26 (30%) patients. A significant increase was observed in the diameters of TST that were repeated on the first year of TNF-α antagonist treatment (9.15 ± 0.55) compared to their initial diameters (6.60 ± 0.51) (P < 0.001). Increased TST responses in patients receiving TNF-α antagonists may be associated with the restoration of suppressed immune reactivity against TB antigens with the decreased disease activity. The meaning of TST conversion in the definition of latent TB infection and the need for chemoprophylaxis in these patients remains to be answered by further studies.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号