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   4942篇
  免费   206篇
  国内免费   43篇
耳鼻咽喉   16篇
儿科学   112篇
妇产科学   167篇
基础医学   560篇
口腔科学   57篇
临床医学   295篇
内科学   1295篇
皮肤病学   102篇
神经病学   372篇
特种医学   312篇
外科学   874篇
综合类   18篇
预防医学   107篇
眼科学   80篇
药学   210篇
中国医学   23篇
肿瘤学   591篇
  2023年   24篇
  2022年   25篇
  2021年   102篇
  2020年   45篇
  2019年   64篇
  2018年   122篇
  2017年   91篇
  2016年   104篇
  2015年   105篇
  2014年   136篇
  2013年   233篇
  2012年   313篇
  2011年   331篇
  2010年   217篇
  2009年   170篇
  2008年   306篇
  2007年   347篇
  2006年   325篇
  2005年   341篇
  2004年   373篇
  2003年   323篇
  2002年   315篇
  2001年   71篇
  2000年   61篇
  1999年   67篇
  1998年   86篇
  1997年   51篇
  1996年   75篇
  1995年   48篇
  1994年   37篇
  1993年   39篇
  1992年   37篇
  1991年   29篇
  1990年   22篇
  1989年   16篇
  1988年   12篇
  1987年   19篇
  1986年   11篇
  1985年   13篇
  1984年   7篇
  1983年   9篇
  1979年   6篇
  1978年   7篇
  1975年   6篇
  1974年   5篇
  1972年   6篇
  1971年   8篇
  1970年   6篇
  1969年   4篇
  1968年   6篇
排序方式: 共有5191条查询结果,搜索用时 31 毫秒
91.
We report a case of fibrolamellar hepatocellular carcinoma, which occurred in a 58-year-old man with normal liver function. Preoperative ultrasonography, computed tomography and magnetic resonance imaging depicted a large tumor in the left lateral segment, which was compatible with the typical radiological features of fibrolamellar hepatocellular carcinoma. He underwent left lobectomy and no lymphadenopathy or distant metastasis was demonstrated. Macroscopic findings of the resected liver demonstrated a well-defined whitish-yellow tumor with a central scar. Microscopic findings of the tumor showed cords of tumor cells, which were surrounded by abundant collagenous fibrous tissue arranged in a lamellar distribution. He has been doing well for approximately one year since the surgery without any signs of recurrence. In addition, we discuss the clinicopathological features of fibrolamellar hepatocellular carcinoma based on a review of 22 Japanese patients who have been previously reported.  相似文献   
92.
A major problem in treating hepatocellular carcinoma (HCC) is intrahepatic recurrence after partial hepatectomy, despite the relatively early detection now possible due to recent developments in non-invasive diagnostic modalities. The present study evaluated the usefulness of preventive therapy for intrahepatic recurrence of HCC. In order to suppress intrahepatic recurrence in HCC patients at high risk of recurrence after tumor removal, we performed preventive transarterial chemotherapy in 23 such patients. Doxorubicin, at a dose of 0.5 mg/kg body weight, was administered, via a catheter inserted at the junction of the common hepatic artery and the gastroduodenal artery, every 2 weeks for the first 2 months, and every month thereafter for at least 1 year. The control group consisted of 30 patients with similar risk of recurrence who underwent partial hepatectomy during the same period without receiving transarterial preventive therapy. The 1-, 2-, 3-, and 5-year cumulative cancer-free survival rates in patients who received transarterial preventive chemotherapy after partial hepatectomy were 87.0%, 47.1%, 21.2%, and 21.2%, respectively, compared to 53.3%, 30.0%, 20.0%, and 13.3%, respectively, in the control group (P<0.05). The 1-, 2-, 3-, and 5-year cumulative overall survival rates were 95.7%, 81.2%, 58.4%, and 48.7%, respectively, in the preventive chemotherapy group, compared to 70.0%, 49.4%, 41.7%, and 19.5%, respectively, in the control group (P<0.05). Thus, the present study demonstrates the limited but significant effect of preventive transarterial chemotherapy for the intrahepatic recurrence of HCC after partial hepatectomy.  相似文献   
93.
Annals of Nuclear Medicine - Although previous studies have investigated age and gender effects on striatal subregional dopamine transporter (DaT) binding, these studies were mostly based on a...  相似文献   
94.
Dysplasminogenaemia has been reported in patients with retinochoroidal vascular disorders. The precise genetic defects of these cases, however, remain unclear because of the limitations of conventional diagnostic techniques. In this study, three patients with these diseases were investigated at the DNA level for the first time to define the molecular bases of these disorders. Polymerase chain reaction–restriction fragment length polymorphism analysis revealed that all three cases carried the same Ala601-Thr mutation. This defect may also play a role in the pathogenesis of circulation disorders in small local vessels because of reduced fibrinolytic activity due to decreased functional plasminogen levels.  相似文献   
95.
Crow-Fukase syndrome (CFS) is a multisystemic disorder. Because it is characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, sclerotic bone lesions, and skin changes it is also known as POEMS syndrome. Extravascular volume overload is also one of the main symptoms. Uncontrollable extravascular volume overload is one of the major causes of death and one of the negative prognostic factors. Control of the extravascular volume overload is an important therapeutic strategy for this syndrome. We report here a case of CFS with extravascular volume overload resulting in pleural effusion and massive edema in the lower extremities, which was refractory to oral administration of melphalan and prednisolone. The patient's condition correlated with the serum level of vascular endothelial growth factor and markedly improved after administration of high-dose melphalan (200 mg/m2) followed by autologous peripheral blood stem cell transplantation. This approach should be considered in patients with CFS who fail to respond to conventional chemotherapy and have uncontrollable extravascular volume overload.  相似文献   
96.
Summary The long-term efficacy of the positive inotropic and vasodilator drug, pimobendan, was assessed in 21 patients suffering from symptomatic heart failure. Patients were randomized to 16 weeks of double-blind therapy with either 2.5 or 5.0mg/day of pimobendan (n = 10), or a matching placebo (n = 11). Patients were blinded on the study drug if their clinical status had not substantially worsened during the study. Of the placebo-treated patients, 5 patients were withdrawn from the study because of a deterioration of their heart failure, while none of the active treated group was withdrawn because of increased symptoms. Quality of life, assessed by the specific activity scale derived from the metabolic costs of individual physical activity, was 3.45 ± 0.90 (SD) mets in the baseline state and increased significantly after week 16, averaging 5.07 ± 1.40 and 4.67 ± 1.47 mets at weeks 16 and 24, respectively. In the placebo-treated group, the specific activity scale was 3.27 ± 1.21 mets at the baseline and remained unchanged throughout the study period. Patients treated with pimobendan were able to significantly increase their exercise duration. The accompanying increase in peak oxygen uptake was statistically insignificant, due to the limited number of patients enrolled in the study. These results suggest that in contrast to the recent pessimistic view of the long-term efficacy of cardiotonic drugs, pimobendan is beneficial in treating patients with congestive heart failure and may favorably modify their prognosis. Further largescale evaluation of this agent is warranted.  相似文献   
97.
We report a 49-year-old woman with neuromyelitis optica (NMO) spectrum disorder coexisting with Sj?gren's syndrome (SS). She presented with acute brainstem symptoms and transverse myelitis. Brain MRI showed focal high signal intensity lesions in the hypothalamus and the pontine tegmentum on T2-weighted and FLAIR images. MRA revealed stenotic changes of the bilateral middle cerebral artery (MCA), posterior cerebral arteries (PCA) and basilar artery (BA). Spinal MRI revealed hyperintense lesions within the cord extending from the T4 to the T6 level on the T2-weighted image. The patient fulfilled the clinical criteria of primary SS. In addition, anti-AQP4 antibody which is highly specific for NMO was detected in the serum at the acute phase. The patient excellently responded to IVIg while methylprednisolon pulse therapy was not effective. Follow-up MRA displayed complete resolution of the stenosis of the MCA, PCA and BA.  相似文献   
98.
In March 1999, a 54-year-old man with chronic hepatitis C was referred to our hospital because of ruptured hepatocellular carcinoma (HCC) located in Couinaud’s segments 4 and 8. He underwent central bisegmentectomy of the liver with partial resection of the diaphragm. After the first surgery, extrahepatic metastases were found on different occasions in the abdominal wall, thoracic cavity, and greater omentum and were all surgically resected. In February 2001, the serum protein induced by vitamin K absence or antagonist-II (PIVKA-II) level increased markedly to 19?000?mAU/l. Magnetic resonance imaging showed a massive right subphrenic tumor with invasion to the right diaphragm and posterior segment of the liver. The patient underwent en bloc resection of the tumor, diaphragm, posterior segment of the liver, and right lower pulmonary lobe. After the surgery, the PIVKA-II level rapidly decreased, and it has remained within the normal range to date. Two years after the last surgery, the patient is doing well without any extrahepatic recurrence, although small intrahepatic recurrences have been completely treated by radiofrequency ablation and transcatheter arterial chemoembolization. Ruptured HCC often exacerbates the risk of peritoneal dissemination and is usually difficult to completely resect. This is an extremely rare case of a patient who successfully underwent five repeated resections for extrahepatic recurrences after hepatectomy for ruptured HCC.  相似文献   
99.
BACKGROUND: The association between myocardial infarction (MI) and the R353Q polymorphism of the Factor VII (FVII) gene, which reportedly influences FVII concentrations, activated Factor VII (FVIIa), or FVII antigen (FVIIag), remains controversial. METHODS AND RESULTS: The present case - control study in 127 Japanese men with their first MI at or before 45 years of age and 150 matched healthy controls was designed to clarify this association in premature MI. R353Q polymorphism was determined by polymerase chain reaction, and plasma concentrations of FVIIa and FVIIag were assayed. The distribution of the RR, RQ, and QQ genotypes with respect to R353Q polymorphism was 117, 10, and 0 in the patients, and 131, 17, and 2 in the controls. The Q allele was negatively associated with premature MI (odds ratio =0.41, p=0.038). The plasma concentration of FVIIa was slightly higher in patients (55.1+/-40.9 U/L) than in controls (44.8+/-20.2 U/L), but not significantly (p=0.078); the plasma concentration of FVIIag did not differ between patients (88.7+/-15.7%) and controls (87.0+/-9.0%) (p=0.557). Plasma FVIIa concentrations were influenced by R353Q polymorphism (p<0.001). CONCLUSIONS: The Q allele may be protective against premature MI.  相似文献   
100.
OBJECTIVE: To compare the efficacy and safety of two antiplatelet regimens, ticlopidine alone (200 mg daily) and ticlopidine (100 mg daily) plus aspirin (81 mg daily), in patients with ischemic stroke from the Tokai district of Japan. METHODS: A randomized comparative study was performed from April 1992 until December 1995, with follow-up for an average of 1.59 years (maximum: 3 years). Statistical analysis was done on 270 eligible patients (138 treated with ticlopidine alone and 132 treated with ticlopidine plus aspirin). PATIENTS: A total of 276 patients who had cerebral infarction within the previous 1 to 6 months, or one or more transient ischemic attacks within the previous 3 months. RESULTS: The incidence of ischemic and hemorrhagic stroke, myocardial infarction, and other vascular events was 10.1% (n = 14) in the ticlopidine group and 9.8% (n = 13) in the ticlopidine plus aspirin group, showing no significant difference (p = 0.933). There was also no significant difference in the event-free rate between the two groups (p = 0.5003, Kaplan-Meier analysis and log-rank test). Regarding serious adverse reactions, neutropenia occurred in one patient from the ticlopidine group, while gastric ulcer and thrombocytopenia occurred in one patient each from the ticlopidine plus aspirin group. CONCLUSION: We conclude that both antiplatelet regimens are comparable in efficacy and safety for preventing the recurrence of ischemic stroke.  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