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   6749篇
  免费   300篇
  国内免费   35篇
耳鼻咽喉   103篇
儿科学   139篇
妇产科学   82篇
基础医学   884篇
口腔科学   142篇
临床医学   360篇
内科学   1610篇
皮肤病学   222篇
神经病学   516篇
特种医学   256篇
外科学   1199篇
综合类   41篇
一般理论   1篇
预防医学   179篇
眼科学   154篇
药学   298篇
中国医学   11篇
肿瘤学   887篇
  2023年   27篇
  2022年   65篇
  2021年   122篇
  2020年   73篇
  2019年   88篇
  2018年   127篇
  2017年   105篇
  2016年   159篇
  2015年   180篇
  2014年   189篇
  2013年   282篇
  2012年   409篇
  2011年   475篇
  2010年   276篇
  2009年   208篇
  2008年   430篇
  2007年   423篇
  2006年   475篇
  2005年   454篇
  2004年   474篇
  2003年   482篇
  2002年   442篇
  2001年   69篇
  2000年   62篇
  1999年   83篇
  1998年   113篇
  1997年   110篇
  1996年   82篇
  1995年   81篇
  1994年   63篇
  1993年   54篇
  1992年   39篇
  1991年   40篇
  1990年   24篇
  1989年   29篇
  1988年   27篇
  1987年   21篇
  1986年   12篇
  1985年   11篇
  1984年   14篇
  1983年   16篇
  1982年   22篇
  1981年   24篇
  1980年   21篇
  1979年   14篇
  1978年   14篇
  1976年   9篇
  1975年   11篇
  1972年   6篇
  1971年   8篇
排序方式: 共有7084条查询结果,搜索用时 3 毫秒
81.
We evaluated the clinical courses of 216 patients with multiple sclerosis (MS) diagnosed according to the recommended diagnostic criteria of McDonald et al (10). Sixty-five patients clinically displaying selective involvement of the optic nerves and spinal cord were classified as opticospinal MS (OS-MS), while the other 151 showing disseminated involvement of the central nervous system were classified as conventional MS (C-MS). The disease duration did not differ significantly between the two subtypes (11.2 years vs. 11.5 years). In addition to a higher age of onset, female preponderance and higher Kurtzke's expanded disability status scale (EDSS) scores, the OS-MS patients showed a markedly lower frequency of secondary progressive MS than the C-MS patients (4.6% vs. 29.1%, p=0.0001). The EDSS scores of the C-MS patients were significantly correlated with the disease duration, while those of the OS-MS patients were not. Among the C-MS patients, the frequency of secondary progressive MS was significantly more common in patients with a disease duration of more than 10 years than in those with a shorter duration. These results suggest that the irreversible disability in OS-MS is determined by relapses, rather than by chronic progression, whereas C-MS has a similar clinical course to MS in Westerners.  相似文献   
82.
Corynebacterium propinquum, which is included in Corynebacterium group ANF-3, exists as a commensal in the oral flora. This organism has not yet been fully recognized as a respiratory pathogen. We previously reported that the first case with respiratory infection caused by C. propinquum. On the other hand, Corynebacterium pseudodiphtheriticum is recognized as a causative organism in respiratory infections. Recently we experienced two cases with C. propinquum respiratory infections in our hospital. Three types of the onset such as a community-acquired infection, a hospital-acquired infection, and a nursing home acquired infections were observed. Our analysis indicated that gram staining of the purulent sputum is an essential tool to evaluate whether C. propinquum is a respiratory pathogen or not, because this organism is a commensal bacteria.  相似文献   
83.
Two-staged pancreatoduodenectomy, including exteriorization of the pancreatic juice and second-look pancreaticojejunostomy, has been recommended for high-risk patients to avoid pancreatic leakage, which often causes intra-abdominal hemorrhage. We present a new technique of interventional pancreaticojejunostomy under both fluoroscopy and endoscopy without second-look laparotomy. A 77-year-old woman with local recurrence and liver metastasis from colon cancer underwent hepato-pancreatoduodenectomy with the external drainage of pancreatic juice via the pancreatic duct tube without pancreaticojejunostomy. Two months later, the jejunum was punctured with the insertion of a 5-F needle-knife into the pancreatic fistula during endoscopic observation of jejunal lumen, followed by the insertion of two 0.35-inch guidewires into the jejunum and the pancreatic fistula. Finally, a 10-Fr stenting tube was placed between the jejunum and the pancreatic fistula. No complications developed.  相似文献   
84.
BACKGROUND/AIMS: The anti-cancerous effect on hepatocellular carcinoma of a newly established form of thermotherapy, which uses an implant heating system, was evaluated. As a new material for application in hyperthermia, the authors developed a powder type Mg-ferrite complex that produces heat under a relatively low-power magnetic field. METHODOLOGY: This material suspended in Lipiodol was injected into tumors on the backs of mice that consisted of human hepatocellular carcinoma cells. Hyperthermia was performed by directing a magnetic charge on tumor-bearing mice that contained the Mg-ferrite complex. The temperature of the tumor was kept at 42-43 degrees C, while the magnetic field power ranged from 50 to 80G. RESULTS: A 10-min hyperthermia treatment was insufficiently effective against tumor growth. Systemic injection of doxorubicin (ADM) before hyperthermia appeared to enhance the anti-cancerous effect, but the difference was little and did not reach a statistically significant level (repeated measure analysis of variance). The anticancerous effect of hyperthermia for 15 minutes, in contrast, was marked. The nodules had almost completely disappeared by the end of the experiment. CONCLUSIONS: In conclusion, it is suggested that hyperthermotherapy using this newly developed Mg-ferrite complex might become an option for low-invasive therapy for advanced hepatocellular carcinoma in humans.  相似文献   
85.
Pseudohypoparathyroidism type Ia (PHP-Ia), one of 4 types of PHP, is a genetic disease characterized by clinical hypoparathyroidism caused by parathyroid hormone (PTH) resistance. In addition, patients with PHP-Ia show resistance to other hormones as well as Albright's hereditary osteodystrophy (AHO), a constellation of features including short stature, obesity, brachydactyly, ectopic ossifications, and/or mental retardation. Hypocalcemia is one of the hallmarks of PHP-Ia, but several PHP-Ia patients have been described to have normocalcemia. We encountered a 10-year-old girl with typical Albright's hereditary osteodystrophy with round face, short stature, brachydactyly, and obesity. Biochemical examination showed normocalcemia and increased PTH levels. Ellsworth-Howard test did not show any responses of urinary cAMP and phosphate. Based on these findings, she was diagnosed as having PHP-Ia with normocalcemia. Sequencing analysis of the GNAS gene identified a heterozygous missense mutation in exon 13 (R385H), which was previously reported in a PHP-Ia patient. The exact reason for her normocalcemia is not determined, but we must recognize heterogeneous biochemical findings even in PHP-Ia.  相似文献   
86.
87.
88.
OBJECTIVES: We sought to describe clinical and laboratory findings for a large cohort of patients with thienopyridine-associated thrombotic thrombocytopenic purpura (TTP). BACKGROUND: The thienopyridine derivatives, ticlopidine and clopidogrel, are the 2 most common drugs associated with TTP in databases maintained by the U.S. Food and Drug Administration (FDA). METHODS: Clinical reports of TTP associated with clopidogrel and ticlopidine were identified from medical records, published case reports, and FDA case reports (n = 128). Duration of thienopyridine exposure, clinical and laboratory findings, and survival were recorded. ADAMTS13 activity (n = 39) and inhibitor (n = 30) were measured for a subset of individuals. RESULTS: Compared with clopidogrel-associated TTP cases (n = 35), ticlopidine-associated TTP cases (n = 93) were more likely to have received more than 2 weeks of drug (90% vs. 26%), to be severely thrombocytopenic (84% vs. 60%), and to have normal renal function (72% vs. 45%) (p < 0.01 for each). Compared with TTP patients with ADAMTS13 activity >15% (n = 13), TTP patients with severely deficient ADAMTS13 activity (n = 26) were more likely to have received ticlopidine (92.3% vs. 46.2%, p < 0.003). Among patients who developed TTP >2 weeks after thienopyridine, therapeutic plasma exchange (TPE) increased likelihood of survival (84% vs. 38%, p < 0.05). Among patients who developed TTP within 2 weeks of starting thienopyridines, survival was 77% with TPE and 78% without. CONCLUSIONS: Thrombotic thrombocytopenic purpura is a rare complication of thienopyridine treatment. This drug toxicity appears to occur by 2 different mechanistic pathways, characterized primarily by time of onset before versus after 2 weeks of thienopyridine administration. If TTP occurs after 2 weeks of ticlopidine or clopidogrel therapy, therapeutic plasma exchange must be promptly instituted to enhance likelihood of survival.  相似文献   
89.
A chronic myeloproliferative disorder associated with monosomy 7 is described in a 3 1/2-year-old boy. His presenting features closely resembled those of juvenile chronic myeloid leukaemia (JCML). Cytogenetic study of bone marrow cells showed that all of the metaphases examined had chromosome 7 deletions. He developed an erythroblastic phase, characterized by anaemia, marked erythroid hyperplasia of bone marrow and the appearance of nucleated red blood cells in the peripheral blood. During the erythroblastic phase, blood transfusion resulted in a suppression of erythropoiesis as evidenced in both the peripheral blood and bone marrow. The in vitro culture studies showed that the erythroid precursor was dependent upon erythropoietin (Ep) for differentiation and proliferation during the erythroblastic phase. However, the Ep dose-response curve showed that a peak of erythroid colony formation occurred at a lower concentration than in the healthy controls. These findings suggest that although the erythroid precursor remains under the control of Ep, it has an increased sensitivity to Ep during the erythroblastic phase of monosomy 7.  相似文献   
90.
The new World Health Organization (WHO) classification of hematologic malignancies has incorporated t(8;21) myelodysplastic syndromes (MDS) according to the French-American-British classification into the category of acute myeloid leukemia (AML) with t(8;21)(q22;q22), while our knowledge about clinicopathological features of t(8;21) oligoblastic leukemia is still limited. We present our experience with 12 patients meeting the FAB diagnostic criteria of MDS and having t(8;21), who were compared to 43 t(8;21) AML patients. The MDS and AML patients shared most hematomorphologic, immunophenotypic, and clinical features, whereas the differences lay along myeloid maturation. The MDS patients had higher percentages of circulating neutrophils and marrow myeloid cells beyond promyelocytes than the AML patients. The incidence of Auer rods in mature neutrophils in MDS was significantly higher than that in AML, and furthermore, the neutrophils in MDS more commonly contain t(8;21) than in AML. Our findings support the rationale for the WHO classification, and future studies on large patient populations should help clarify whether the spontaneous differentiation potential could be actively associated with a hematological manifestation of t(8;21) leukemias.  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