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   7233篇
  免费   380篇
  国内免费   58篇
耳鼻咽喉   141篇
儿科学   230篇
妇产科学   85篇
基础医学   847篇
口腔科学   153篇
临床医学   431篇
内科学   2067篇
皮肤病学   92篇
神经病学   378篇
特种医学   436篇
外科学   1272篇
综合类   30篇
一般理论   1篇
预防医学   146篇
眼科学   125篇
药学   356篇
中国医学   13篇
肿瘤学   868篇
  2024年   6篇
  2023年   67篇
  2022年   163篇
  2021年   258篇
  2020年   114篇
  2019年   181篇
  2018年   216篇
  2017年   183篇
  2016年   198篇
  2015年   197篇
  2014年   257篇
  2013年   332篇
  2012年   534篇
  2011年   550篇
  2010年   287篇
  2009年   224篇
  2008年   419篇
  2007年   467篇
  2006年   457篇
  2005年   489篇
  2004年   400篇
  2003年   445篇
  2002年   423篇
  2001年   53篇
  2000年   41篇
  1999年   73篇
  1998年   96篇
  1997年   68篇
  1996年   67篇
  1995年   72篇
  1994年   49篇
  1993年   59篇
  1992年   37篇
  1991年   28篇
  1990年   16篇
  1989年   23篇
  1988年   20篇
  1987年   10篇
  1986年   6篇
  1985年   9篇
  1984年   9篇
  1983年   9篇
  1982年   6篇
  1981年   12篇
  1980年   10篇
  1979年   9篇
  1978年   3篇
  1977年   4篇
  1976年   4篇
  1974年   3篇
排序方式: 共有7671条查询结果,搜索用时 0 毫秒
131.
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   
132.
BACKGROUND/AIMS: H. pylori uses the sialic acid-binding adhesin (SabA) to recognize Lewis X (LeX) antigen of gastric epithelial cells. SabA is associated with nonopsonic activation of human neutrophils. The aims of this study were to examine the association of bacterial sabA status to the presence of anti-LeX antibody in host and the grade of gastritis. METHODOLOGY: 44 H. pylori strains cultured from gastric biopsies were examined by PCR for presence of 23SrRNA, cagA, and sabA. Serum samples were obtained from all the patients to measure the level of anti-LeX antibody. Histological grade of gastritis was graded according to the updated Sydney System. RESULTS: 23SrRNA gene and the cagA gene were seen in all the samples while 21 strains were sabA positive. The mean titer of anti-LeX antibody was 0.09 and 0.18 in patients infected with sabA-positive and -negative strain, respectively (NS). The grade of inflammatory infiltration was not significantly different between groups in both the corpus and the antral mucosa. CONCLUSIONS: Possession of the sabA gene by infected H. pylori strain might not associate with the presence of anti-LeX antibody in the host. Possession of sabA gene by infected H. pylori might not associate with severity of gastric mucosal inflammation.  相似文献   
133.
We report a case of hepatocellular carcinoma (HCC) that developed 77 months following sustained and complete response to interferon (IFN) therapy for chronic hepatitis C. A 67-year-old Japanese woman presented with a small mass in the liver that was diagnosed as HCC, 77 months after having completed IFN therapy and having shown a complete response to the therapy with sustained normalization of serum aminotransferases and eradication of serum hepatitis C virus (HCV). Hepatitis C virus RNA was also not detected in the resected tumorous and non-tumorous liver tissues by polymerase chain reaction. This suggests that all patients with chronic HCV infection should be followed closely for as long as possible for the potential development of HCC, even after a complete and sustained response to IFN treatment.  相似文献   
134.
The pathophysiology of aortic aneurysm is complex and it has remained unclear how frequently arteriomegaly, a diffuse dilatation of the artery, is associated with aneurysm. Therefore, ultrasonic study of the carotid artery was conducted to clarify this issue in a large number of subjects. Carotid ultrasonography was performed in 1,108 Japanese men aged 50 or older, and the results of 379 patients with arteriosclerotic aortic aneurysm (AA) were compared with those of 211 patients with peripheral arterial disease, 65 patients with aortic dissection, 232 hypertensive subjects, and 221 normotensive subjects. The carotid diameter was measured bilaterally at two points on the common carotid artery, and we defined carotid arteriomegaly as an arterial diameter in the 95th percentile or above that in the normotensive control group according to the relevant age subgroups. The incidence of carotid arteriomegaly in the AA group (25.9%) was significantly higher than in the other groups (p < 0.01) even when adjusted for body height and blood pressure. In the arteriomegaly subgroup, hypertension and cigarette smoking was significantly more frequent than in the non-dilated artery subgroup. This study demonstrates that one fourth of patients with aortic aneurysm have arteriomegaly as a generalized systemic abnormality in the arterial wall.  相似文献   
135.
A 57-year-old man consulted our hospital with a history of the gradual onset of dyspnea and a productive cough. Chest computed tomographic (CT) scans showed a nodular shadow in a cavity lesion, and reticulonodular, cystic, and ground-grass opacities in the bilateral lung fields with honeycombing. He was diagnosed as having pulmonary aspergilloma and idiopathic pulmonary fibrosis (IPF). As an outpatient, he suffered from dyspnea upon physical exertion with exacerbation of the high-resolution CT (HRCT) opacities. An inhalation provocation test for Aspergillosis fumigatus was positive and chronic hypersensitivity pneumonitis (CHP) caused by Aspergillus was finally diagnosed. Insidious CHP is sometimes misdiagnosed as IPF. The diagnosis of insidious CHP should be made on the basis of a detailed history, specific HRCT findings, and lymphocyte-dominant bronchoalveolar lavage fluid cell findings.  相似文献   
136.
BACKGROUND: To evaluate the imaging possibility of a newly designed electronic radial scanning echoendoscope (ER-ES). METHODS: In the in vivo study of swine, we obtained B-mode endoscopic ultrasonography (EUS) images of the gastric and gallbladder (GB) walls and checked the ability to detect Doppler signals using ER-ES and electronic linear array echoendoscope (EL-ES). Furthermore, in the ex vivo study of swine, B-mode EUS images of fixed gastric and GB wall specimens were obtained using ER-ES, EL-ES and mechanical radial scanning echoendoscope (MR-ES). In the study of resected human specimens, we obtained B-mode EUS images of five resected GB specimens (three normal GB, one cholecystitis and one cancerous) using the three types of echoendoscope. RESULTS: In the in vivo study of swine, ER-ES and EL-ES depicted the gastric walls as five-layered, and the GB walls as single-layered structures. The ability to detect Doppler signals was equal between ER-ES and EL-ES. In the ex vivo study of swine, ER-ES, MR-ES and EL-ES equally delineated the gastric walls as five-layered and GB walls as three-layered structures. In the study of resected human specimens, results demonstrated the normal GB walls as three-layered, the cholecystitis as a combination of outer high-echoic and inner low-echoic layers, and the cancer as a protruded tumor. CONCLUSIONS: We conclude that ER-ES has faculties for making B-mode images as well as EL-ES and MR-ES. In addition, in the in vivo study, ER-ES can analyze blood flow information as well as EL-ES.  相似文献   
137.
We report a case of a ruptured aneurysm in the anterior superior pancreaticoduodenal artery (PDA) with hypovolemic shock managed successfully by superselective transcatheter arterial embolization of the aneurysm. A75-year-old male presented to our hospital with hematemesis and melena. On admission, he was in shock. Angiography showed an aneurysm about 1?cm in diameter in the anterior superior PDA. However, extravasation of contrast medium was not seen owing to hypovolemic shock. A catheter was inserted into the aneurysm, and superselective microcoil embolization of the PDA aneurysm was successfully achieved. After the microcoil was inserted into the aneurysm itself, it was observed that duodenal vascularity and pancreaticoduodenal arcades were preserved and aneurysm was not present. There was no complication such as necrosis or abscess formation in the pancreas. The patient recovered and is doing well after 18 months of follow-up. Superselective transcatheter arterial embolization should be considered as the initial treatment of choice for all peripancreatic aneurysms.  相似文献   
138.
We have shown previously that Cyp11b1, an 11beta-hydroxylase responsible for glucocorticoid biosynthesis in the adrenal gland, was induced by cAMP in androgen-producing Leydig-like cells derived from mesenchymal stem cells. We found that Cyp11b1 was induced in male Leydig cells, or female theca cells, when human chorionic gonadotropin was administered in immature mice. Expression of Cyp11b1 in rodent gonads caused the production of 11-ketotestosterone (11-KT), a major fish androgen, which induces male differentiation or spermatogenesis in fish. As in teleosts, plasma concentrations of 11-KT were elevated in human chorionic gonadotropin-treated mice. In contrast to teleosts, however, plasma concentrations of 11-KT were similar in both sexes, despite levels of testosterone, a precursor substrate, being about 20 times higher in male mice. Because expression of 11beta-hydroxysteroid dehydrogenase type 2, was much higher in the mouse ovary than in the testis, conversion of testosterone into 11-KT may occur more efficiently in the ovary. In a luciferase reporter system that was responsive to and activated by androgens, 11-KT efficiently activated mammalian androgen receptor-mediated transactivation. Our results suggest that the androgen metabolic pathway is conserved between teleosts and mammals, despite sexual dominance and reproductive functions of 11-KT being altered during evolution.  相似文献   
139.
A patient with myeloid/natural killer (NK) cell precursor acute leukemia who was also homozygous for protein C deficiency was treated and showed a complete remission while he simultaneously received low molecular weight heparin. He presented with fever spikes, lymphadenopathy, and a bulky tumor of the anterior mediastinum. A bone marrow aspirate showed the infiltration of immature lymphoblastoid cells. The patient's diagnosis was determined to be myeloid/NK cell precursor acute leukemia by morphologic and immunophenotypic analysis (CD7(+)CD33(+)CD34(+)CD56(+)). The patient developed a thrombosis in his jugular vein on cannulation of the internal jugular vein. An examination of the serum levels and the activities of proteins C and S demonstrated a slight decrease in the protein C level but an undetectable protein C activity. The patient received the diagnosis of homozygous protein C deficiency, because both parents were found to have heterozygous protein C activity. Treatment of the patient's leukemia included induction chemotherapy (Ara-C and idarubicin) with concomitant administration of low molecular weight heparin for his homozygous protein C deficiency. He achieved a complete remission without expressing any thrombosis during the course of chemotherapy. To our knowledge, this is the first case ever described in which acute myeloid leukemia was complicated with homozygous protein C deficiency.  相似文献   
140.
The treatment of bedsores is a particular problem in geriatric medicine. We selected standard drugs that may be effective for the decubitus ulcer, and investigated combination therapy to develop efficient treatment The subjects were 16 patients in whom the grade of the bedsore was evaluated as II to IV according to the Shea's depth classification. Treatment was performed while all patients were on air mats. We selected drugs and treatment methods based on the previously established experimental design of Taguchi. Based on this, we created and adapted 16 different component combination treatment programs in accordance with the L16 rectangular cross table. The following component factors were adopted: A: types of covering substances on the wound surface (Elase ointment, isodine sugar, isodine gel solcoseryl ointment); B: Isalopan powder; C: Spray of 10 ml physiological saline containing 500 microg of prostaglandin (concentration 0.005%); D: daily number of treatments; and F: presence or absence of tapping. We serially measured the wound surface area as an index of the speed of wound healing, and measured the interval (day) until the area decreased to one half of the original size (T1/2, half life). We analyzed data on one combination treatment each in 16 patients. Analysis of variance of the above factors showed significant F values for factors A, B, D and F. The contribution rates for factors A, B, D and F were 37.84%, 8.47%, 14.98% and 13.81%, respectively. The error term (e) was 16.37%. Optimal results were seen in the groups in which solcoseryl ointment had been applied twice a day. In this study, prostaglandin, which had been anticipated to be effective, did not show any effects. The error term (e) suggests the presence of other healing factors including individual differences. Concerning this point, it well be necessary to examine a larger number of patients in the future. With ointment treatment alone, without using an air mat, it was confirmed that bedsore area reduction was extremely unstable. Decompression of the affected part may be a basic prevention factor and essential treatment of bedsores.  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