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   927篇
  免费   37篇
  国内免费   13篇
耳鼻咽喉   22篇
儿科学   84篇
妇产科学   15篇
基础医学   55篇
口腔科学   11篇
临床医学   88篇
内科学   297篇
皮肤病学   7篇
神经病学   55篇
特种医学   29篇
外科学   159篇
综合类   28篇
一般理论   1篇
预防医学   32篇
眼科学   9篇
药学   40篇
肿瘤学   45篇
  2024年   1篇
  2023年   6篇
  2022年   17篇
  2021年   29篇
  2020年   20篇
  2019年   23篇
  2018年   28篇
  2017年   19篇
  2016年   40篇
  2015年   24篇
  2014年   50篇
  2013年   59篇
  2012年   75篇
  2011年   60篇
  2010年   35篇
  2009年   31篇
  2008年   50篇
  2007年   65篇
  2006年   74篇
  2005年   61篇
  2004年   55篇
  2003年   53篇
  2002年   33篇
  2001年   7篇
  2000年   6篇
  1999年   6篇
  1998年   1篇
  1997年   4篇
  1996年   6篇
  1995年   8篇
  1994年   1篇
  1993年   1篇
  1991年   3篇
  1990年   4篇
  1989年   2篇
  1988年   3篇
  1987年   1篇
  1985年   1篇
  1984年   4篇
  1983年   5篇
  1982年   2篇
  1981年   3篇
  1979年   1篇
排序方式: 共有977条查询结果,搜索用时 15 毫秒
21.
Morgagni hernia (MH) is a congenital herniation of the abdominal organs through the subcostosternal portion of the diaphragm. It is a rare type of diaphragmatic hernia that has been associated with other congenital anomalies. The purpose of this clinical review was to determine the incidence of associated anomalies in patients with MH at a major pediatric referral center. The medical records of all patients with the diagnosis of MH were reviewed retrospectively between 1983 and 2006. The age, sex, side of herniation, presenting symptoms and signs, associated anomalies, radiologic features, intraoperative findings, postoperative course, complications, and mortality were recorded. There were 11 males and 5 females. The average age of the patients was 34.5 months (range 2 months–14 years). Twelve patients (75%) had at least one associated congenital malformation and eight (66.6%) of them had multiple anomalies. Six (37.5%) patients had a chromosomal anomaly, Down’s syndrome in five and Turner syndrome in one. MH has a high incidence of associated congenital malformations.  相似文献   
22.

Background

To evaluate the patterns of lymphatic spread in epithelial ovarian cancer (EOC) macroscopically confined to the ovary and to determine risk factors for lymph node metastasis.

Materials and methods

All patients with clinically apparent stage IA/B/C EOCs who underwent staging surgery between January 2003 and February 2013 were retrospectively identified.

Results

Two hundred and thirty-six (n = 236) consecutive patients were operated for primary epithelial ovarian carcinoma. Sixty-two of these patients (26.2 %) who underwent a comprehensive staging procedure including pelvic and paraaortic lymphadenectomy were diagnosed with tumors confined to one or two ovaries (stage IA/B/C). Of these 62 patients, 17 (27.4 %) had upstaged disease and 8 (12.9 %) had lymph node metastasis. Tumor histology was serous in 25 patients (40.3 %), mucinous in 23 patients (37 %), endometrioid in 9 patients (14.5 %), and clear cell in 5 patients (8 %). Positive lymph node status was found in 20 % (5/25) of those with serous histology while this rate was only 8.1 % (3/37) in those with non-serous disease. Although the presence of ascites was not associated with an increased risk of lymph node involvement (p = 0.24), positive peritoneal cytology (p = 0.001) and grade 3 disease (p = 0.001) were significant predictors of lymph node involvement.

Conclusion

All patients diagnosed with EOC macroscopically confined to the ovary should be considered for comprehensive staging surgery including pelvic and paraaortic lymphadenectomy.  相似文献   
23.
Blank firing pistols are generally considered to be harmless and these guns are not accepted as being firearms in most countries. Due to lack of legal regulations these guns are easily purchased by anyone aged over 18 years. Reports of serious injuries and even fatalities due to these guns are increasing in the literature.These guns when modified or even unmodified can cause serious and potentially fatal injuries. Without doing any changes to the barrel, using blank or tear gas cartridges, firing at contact range can cause penetration of gas into the body including bone originated from gunpowder.We report two suicide cases shooting themselves at temporal region with a blank cartridge gun at contact range. There was no foreign body on radiological examination and there was no trajectory of a bullet inside the brain. In both cases the wound was at the right temporal region and there was defect at temporal bone. There was circular soot around this bone defect. The injury of the brain tissue was localized at the level of the defect but there was widespread subarachnoidal bleeding.We discussed the potential danger of these guns and stressed the need of legal regulations concerning these guns.  相似文献   
24.
The pathophysiology of human varicocele is not fully understood. We investigated vasoconstrictor reactivity, endothelial function and morphological changes in different grades of varicocele to clarify the pathophysiology. Contractile responses to phenylephrine, norepinephrine, serotonin and histamine were determined in isolated human varicose spermatic veins using the organ bath technique. Endothelial function was tested with acetylcholine-induced relaxation after phenylephrine-induced precontraction in the absence and presence of nitric oxide synthase inhibitor, L-NAME, and cyclooxygenase inhibitor, indomethacin. The cyclic guanosine monophosphate (cGMP) level was measured in the spermatic vein and peripheral plasma. Morphological changes were evaluated with light microscopy. Phenylephrine, norepinephrine, serotonin and histamine induced concentration-dependent contractions. The maximum contractions for all of these agents except norepinephrine were significantly higher in grade III than grade I and II (P<0.05). The sensitivity to phenylephrine was significantly higher in grades II and III than in grade I (P<0.05). In the presence of L-NAME and indomethacin, the difference from respective control phenylephrine-induced contractions was higher in grade I and II than grade III. Acetylcholine did not induce stable relaxation but the level of cGMP, which is responsible for the vasorelaxant effect of NO, in veins was lower in grades II and III than grade I (P<0.05). Vessel wall thickness increased in grade II and dilatation developed in grade III when compared to grade I (P<0.05). Our findings suggest that endothelium produces less vasorelaxant which results in the more enhanced effects of vasoconstrictor substances in grade III, indicating that endothelial dysfunction develops at high grades of varicocele.  相似文献   
25.

Purpose:

The aim of this study was to determine the effects of whole blood, crystalloid, and colloid treatment on histopathologic damage of kidney induced by hemorrhagic shock in rats.

Methods:

Fifty-six male Sprague Dawley rats were divided into 8 groups. The carotid artery was cannulated, and systolic arterial pressure (SAP), diastolic arterial pressure (DAP), heart rate (HR), and rectal temperature (RT) were observed during the procedure. The jugular vein also was cannulated, and the SAP was decreased by aspiration of 75% of blood through the jugular vein in the control (nonresuscitated) and study (resuscitated) groups, whereas blood was not diminished in the sham group. The hemorrhagic shock was permitted to last 45 minutes; then, the study group rats were resuscitated with heparinized shed autologous whole blood (WB), normal saline (NS), Lactated Ringer’s solution (LR), hydroxyethyl starch 6% (HES6), hydroxyethyl starch 10% (HES10), or dextran 40 (D40). Histopathologic evaluation was performed under light and electron microscope.

Results:

The RT, SAP, and DAP decreased, and HR increased significantly in the control and study groups during the shock period compared with those of sham group. After volume resuscitation, these parameters changed to preshock levels. Electron and light microscopic examinations of kidneys showed severe proximal tubular degeneration with moderate glomerular damage in the control group; moderate proximal tubular degeneration with mild glomerular damage in the NS, LR, HES6, and HES10 groups; and mild proximal tubular degeneration with no evidence of glomerular damage in the WB and D-40 groups.

Conclusions:

The characteristic ultrastructural features of hemorrhagic shock appear to be severe tubular degeneration and mild to moderate changes in glomeruli. Resuscitation of hemorrhagic shock with whole blood or dextran 40 solution appears to be most favorable therapy in preventing ultrastructural renal damage in rats.  相似文献   
26.
BackgroundNeutrophil/lymphocyte ratio (NLR) has been associated with poor outcomes in patients with cardiovascular diseases. However, little is known about the role of NLR in patients with thromboembolic stroke due to atrial fibrillation (AF). We aimed to compare the NLR ratios between non-valvular AF patients with or without thromboembolic stroke.MethodsA total of 126 non-valvular AF patients with or without stroke were included in the study; 126 consecutive patients (52 males and 74 females), mean age, 70 ± 10.2 years old. No patient had a recent history of an acute infection or an inflammatory disease. Baseline NLR was measured by dividing neutrophil count to lymphocyte count. WBC count > 12.000 cells per μL or < 4.000 cells per μL and high body temperature > 38 º are excluded from the study.ResultsMean NLR was significantly higher among persons with stroke compared to individuals without a stroke (5.6 ± 3.4 vs. 3.1 ± 2.1, p = 0.001). There were no significant differences in RDW levels between the two groups (p > 0.05). HAS-BLED and CHADS2 scores were significantly higher in the stroke group.ConclusionHigher NLR, an emerging marker of inflammation, is associated with thromboembolic stroke in non-valvular AF patients.  相似文献   
27.
28.

Background

To investigate the protective effect of 2-aminoethyl diphenylborinate (2-APB) against ischemia–reperfusion (I/R) injury in the rat kidney by an experimental study.

Materials and methods

Thirty male Sprague-Dawley rats were randomly divided into the following three groups: (1) sham group, (2) I/R group, and (3) I/R + 2-APB group. Renal I/R injury was induced by clamping the left renal pedicle for 45 min after right nephrectomy, followed by 3 h of reperfusion. The therapeutic agent 2-APB was administered intravenously at a dose of 2 mg/kg 10 min before renal ischemia. Glutathione, superoxide dismutase, total antioxidant capacity, malondialdehyde, tumor necrosis factor α, interleukin 6, aspartate aminotransferase, alanine aminotransferase, and creatinine levels were measured from blood samples, and the rats were sacrificed subsequently. Tissue samples were scored histopathologically. Visualization of apoptotic cells was performed using the terminal deoxynucleotidyl transferase dUTP nick end labeling staining method.

Results

2-APB significantly reduced serum malondialdehyde, tumor necrosis factor α, interleukin 6, aspartate aminotransferase, alanine aminotransferase, and creatinine levels in the I/R injury group. However, glutathione, superoxide dismutase, and total antioxidant capacity levels increased significantly. Histopathologic scores were significantly better and the rate of apoptosis was lower in the 2-APB group.

Conclusions

2-APB reduces oxidative stress and damage caused by renal I/R injury. The results of this study demonstrate that 2-APB can be used as an effective agent against I/R injury in the kidney.  相似文献   
29.
Blood coagulation and platelet aggregation were assessed in children, with nephrotic syndrome who were divided into the following groups: (1) relapse without treatment; (2) relapse on steroids; (3) early remission; (4) late remission and (5) steroid resistant. The renal histological findings were also recorded. Plasma antithrombin III (ATIII) levels were markedly reduced in groups 1 and 2, below normal in group 3 and were normal in groups 4 and 5. There was significant urinary loss of AT III in groups 1 and 2 as well as in group 5. Plasma fibrinogen fluctuations exhibited the expected negative correlations with plasma AT III. Reptilase time showed significant prolongation in groups 1, 2 and 3, and was near normal in groups 4 and 5. Platelet aggregation in response to arachidonic acid exhibited aggregation followed by disaggregation in groups 1, 2, 4 and 5, and was normal in group 3. Hyperaggregation in response to decreasing doses of ADP was noted in all patient groups as well as controls with no relationship to serum albumin levels. Aggregation responses to collagen and ristocetin were normal. It is concluded that: 1. The fluctuations in AT III levels in childhood nephrotic syndrome are determined by the response to steroids and not by the renal histology per se. 2. An acquired fibrin polymerization defect (dysfibrinogenaemia) and an abnormality of the prostaglandin pathway of platelet activation, both reversible, are yet other haemostatic abnormalities in childhood nephrosis. 3. The discrepancies in the literature on haemostatic parameters, specially AT III in childhood nephrosis, would not have arisen if their fluctuation in relation to steroid therapy as well as the renal histological features of nephrotic syndrome had been documented simultaneously.  相似文献   
30.
The lipodystrophy syndrome (LDS) is a growing problem in human immunodeficiency virus (HIV)-positive patients treated with highly active antiretroviral therapy (HAART). It is characterized by alterations of body composition and metabolic abnormalities. The goal of the study was to investigate attitudes toward health condition, well-being, and individual appearance in relation to LDS. Outpatients between July and October 2000 in an HIV-specialized unit at the University Hospital of Düsseldorf, Germany, underwent clinical evaluation and received a standardized written questionnaire. Of 389 patients eligible for analysis, 313 patients returned completed questionnaires (response rate, 80.5%). LDS was observed in 37.7%; the predominant manifestation was lipoatrophy of the face (32.9%). Individuals with and without LDS did not differ significantly in their attitude to the quality of their health condition and the amount of disturbance of their well-being by HIV infection. Participants with LDS felt recognizable as HIV-positive by physical appearance in 30.1%, compared to 18.3% in patients without LDS (p = 0.027). This difference became more pronounced after adjustment for gender, age, stage of disease, CD4 cell count, and duration of HAART (odds ratio, 2.04, 95%-confidence interval [CI] 1.09-3.84). In conclusion, LDS does not seem to disturb the general attitude toward health condition and well-being. However, patients presenting with lipodystrophy are about twice as likely to feel recognizable as HIV-positive by their physical appearance. LDS may thus be perceived as a characteristic mark of being HIV-positive by affected persons. A stigmatizing effect and social disadvantages may be the consequences.  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