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   1704篇
  免费   70篇
  国内免费   12篇
耳鼻咽喉   14篇
儿科学   7篇
妇产科学   15篇
基础医学   177篇
口腔科学   21篇
临床医学   173篇
内科学   454篇
皮肤病学   25篇
神经病学   137篇
特种医学   62篇
外科学   242篇
综合类   7篇
一般理论   1篇
预防医学   55篇
眼科学   29篇
药学   119篇
中国医学   2篇
肿瘤学   246篇
  2024年   3篇
  2023年   32篇
  2022年   75篇
  2021年   107篇
  2020年   47篇
  2019年   50篇
  2018年   55篇
  2017年   45篇
  2016年   63篇
  2015年   56篇
  2014年   65篇
  2013年   105篇
  2012年   147篇
  2011年   129篇
  2010年   70篇
  2009年   66篇
  2008年   89篇
  2007年   90篇
  2006年   114篇
  2005年   84篇
  2004年   66篇
  2003年   72篇
  2002年   62篇
  2001年   7篇
  2000年   5篇
  1999年   5篇
  1998年   5篇
  1997年   7篇
  1996年   9篇
  1995年   4篇
  1994年   2篇
  1993年   2篇
  1992年   12篇
  1991年   8篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   8篇
  1985年   4篇
  1984年   4篇
  1983年   1篇
  1979年   2篇
  1973年   1篇
排序方式: 共有1786条查询结果,搜索用时 15 毫秒
81.
We evaluated the results of medical treatment for male prolactinomas. We encountered eight patients with male prolactinomas. The age was 25 to 54 years old (mean 43 years) and the chief clinical symptoms were visual acuity/field defect in three patients, pituitary apoplexy in one patient, disturbance of ejection in one patient, generalized convulsion in one patient, headache in one patient and general fatigue in one patient. The serum prolactin level was 279 to 7,360 ng/ml (mean 2,832 ng/ml). The tumors in all patients were large with a mean diameter of 34.9 mm (range, 21 to 43 mm). In only one patient, the operation was performed due to pituitary apoplexy. All the patients were treated by medication, with bromocriptine being used in seven patients and terguride in one. The follow-up period was 0.8 to 13 years (mean 5.9 years) and, in all patients, the medical treatment was continued. The tumor decreased in size in all patients and the serum prolactin level at the last follow-up observation was 0.5 to 70.5 ng/ml (mean 26.9 ng/ml). All the neurological symptoms disappeared in the early stage of treatment. As for the complications of medical treatment; in one patient, orthostatic hypotension occurred during the initial administration of bromocriptine and one patient suffered CSF leakage two months after the administration of bromocriptine, so the repair of the sella floor by transsphenoidal surgery was necessary. The medical treatment for male prolactinomas is effective for a long term and should be the primary treatment for the male prolactinomas. In conclusion, patients can maintain a good quality of life for a long time by using dopamine agonists.  相似文献   
82.
PURPOSE: To elucidate the diurnal variation of human corneal curvature with regard to gender and menstrual cycle. METHODS: Changes in corneal curvature and intraocular pressure (IOP) were measured over 24 hours in 14 young adults using corneal topography and a non-contact tonometer. In study 1, seven males and seven females (after menses) were measured. In study 2, four females out of the seven volunteers who participated in study 1 were measured again during menses. RESULTS: The females after menses showed a remarkable diurnal variation throughout 24 hours. A significant difference between the light-wake periods and dark-sleep periods of 0.83 +/- 0.15 D was found (P < .01). Corneal curvature was significantly flatter during menses than after menses in the light-wake period (P < .05). In the males, no significant diurnal change (0.21 +/- 0.12 D) was measured in corneal curvature. CONCLUSIONS: Diurnal variation of corneal curvature was significant, approximately 0.83 D in young females after menses, and corneal curvature became flatter during menses in young females. Diurnal variation of corneal curvature is an important parameter for planning refractive surgery and contact lens wear.  相似文献   
83.
PURPOSE: We report 2 patients with refractory liver metastatic tumor after esophagectomy for advanced esophageal cancer, who responded markedly to locoregional cellular immunotherapy by repeated intraarterial infusions of autologous tumor cell-activated T lymphocytes (AuTL), even after they failed the standard chemotherapy of cisplatin (CDDP) and 5-fluorouracil (5-FU). METHODS: AuTL administrations were made through the hepatic artery via a subcutaneous reservoir located at the right upper leg. Six injections were administered to both patients, repeated at 2-week intervals. The total number of administered T cells reached 2.4 x 10(9) and 3.1 x 10(9), respectively. RESULTS: A 39% and 51% regression in each infused field, compared with the size of liver tumor before treatment, was observed by computed tomography (CT) scan in patient 1 and 2, respectively. The responses continued up to the 10th and 11th month after the intraarterial infusion, confirmed by follow-up CT scan. The adverse effects of intraarterial immunotherapy were tolerable, with grade 1-2 fever and nausea in each patient. CONCLUSIONS: Clinical regression of liver metastases of esophageal cancer was observed in both patients who received this intraarterial cellular immunotherapy. Liver metastases of esophageal cancer may be controlled effectively and safely by repeating the intraarterial AuTL infusion as a locoregional immunotherapy over a long period.  相似文献   
84.
BACKGROUND: Recent studies suggest that 3-hydroxy-3-methylglutaryl co-enzyme A reductase inhibitors (statins) exert their protective effects against cardiovascular diseases independently of their cholesterol-decreasing effects. OBJECTIVE: To clarify the effect of a statin on hypertensive nephrosclerosis. METHODS: We treated stroke-prone spontaneously hypertensive rats (spSHRs) chronically, starting at the age of 4 weeks, with cerivastatin (2 mg/kg per day by gavage) or vehicle. Physiological parameters, plasma chemistry and urine protein excretion were analysed. At 14 weeks of age, the rats had their kidneys removed for use in assays. RESULTS: Compared with vehicle treatment, statin treatment reduced proteinuria and renal injury independently of blood pressure and cholesterol concentrations in spSHRs. Although expression of adhesion molecules and infiltration of inflammatory cells were not different whether or not cerivastatin treatment was used, renal fibrosis was significantly reduced in statin-treated spSHRs. We also found that expression of transforming growth factor-beta1 in kidneys was significantly inhibited in statin-treated spSHRs. CONCLUSION: Cerivastatin prevents or retards hypertension-induced renal injury via inhibition of renal fibrosis and proteinuria. These results show the potential of statins as protective tools against proteinuric renal diseases, independent of their cholesterol-decreasing effects.  相似文献   
85.
A 6-year-old girl, who had received a ventriculoperitoneal (VP) shunt using the Codman-Hakim programmable valve system at age 3 months, presented with intractable seizures. Neuroimaging studies showed migration of the proximal part of the system, including the prechamber, into the cranium through the right frontal burr hole. Electroencephalography showed spike-and-wave complexes in the right hemisphere including the site of the migration. The ictus was resolved following revision surgery. The clinical findings suggested the seizures were due to irritation of the brain parenchyma by the migrated system. Proximal migration of a VP shunt may cause both shunt failure and additional focal symptoms.  相似文献   
86.
Background Reactive oxygen species are as being related to the pathophysiology of endstage renal disease (ESRD). We measured the plasma hydroxyl radical (·OH)-producing ability and ·OH-scavenging activity in patients with ESRD to clarify the pathophysiological states involved. Methods We used electron spin resonance to measure plasma N-t-butyl-α-phenylnitron radical spin adduct (pPBN rsa) as ·OH-producing ability and plasma 3,3,5,5-tetramethyl-1-pyrroline-N-oxide radical spin adduct (pM4PO rsa) as ·OH-scavenging activity. Oxidative injuries were evaluated by determining oxidised low-density lipoprotein (Ox-LDL). Results The pPBN rsa of the ESRD patients was lower than that of the controls (1.83 vs 2.94 μmol/g protein). The pM4PO rsa of the ESRD patients was higher than that of the controls (3.85 vs 3.15 mmol l-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-yl hydrogen phosphate] potassium salt (EPC-K1)/g protein). The pPBN rsa and pM4PO rsa were correlated, both in the ESRD patients and in the controls (r = 0.47 and r = 0.53). Ox-LDL was correlated with hemodialysis (HD) duration (r = 0.49) and was negatively correlated with pPBN rsa (r = −0.54), which indicates that oxidative stress was increased as HD therapy was prolonged and suppressed pPBN rsa. Conclusions There was an imbalance between ·OH-producing ability and ·OH-scavenging activity, in the ESRD patients, and this may be responsible for compromising the health of ESRD patients.  相似文献   
87.
88.
Selective cleavage of the Glu395-Ser396 bond of brevican, one of the major proteoglycans in adult brain tissues, is thought to be important for glioma cell invasion. Our previous biochemical study demonstrated that ADAMTS-4, a member of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family, has such an activity. In the present study, we examined brevican-degrading activities of ADAMTS-1, -4 and -5 at the cellular level, and their expression and localization in human glioma tissues. In 293T transfectants expressing ADAMTS-4 or ADAMTS-5, brevican was cleaved into two major fragments in an identical pattern, but no such degradation was observed with ADAMTS-1 transfectants. When the expression levels of these ADAMTS species were examined by real-time quantitative PCR, only ADAMTS-5 was found to be overexpressed in glioblastoma tissues compared to control normal brain tissues (P <0.05). In situ hybridization and immunohistochemistry demonstrated that ADAMTS-5 is expressed predominantly in glioblastoma cells. Forced expression of ADAMTS-5 in glioma cell lines stimulated cell invasion. These results demonstrate for the first time that ADAMTS-5 is capable of degrading brevican and is overexpressed in glioblastoma cells, and suggest that ADAMTS-5 may play a role in glioma cell invasion through the cleavage of brevican.  相似文献   
89.
BACKGROUND: In patients on long-term peritoneal dialysis (PD), angiogenesis and vasculopathy are observed in the peritoneum, and the degree of vascularization correlates with the area of fibrotic tissue, suggesting the involvement of angiogenesis in the progression of peritoneal fibrosis. The aim of the present study was to evaluate the effect of TNP-470, an anti-angiogenic compound, on the development of peritoneal fibrosis induced by chlorhexidine gluconate (CG). METHODS: Peritoneal fibrosis was induced by injection of CG into peritoneal cavity of Institute for Cancer Research (ICR) mice. TNP-470 was injected subcutaneously with CG. Mice were sacrificed, and peritoneal tissues were dissected out at days eight and 16 after CG and TNP-470 injection. The expression patterns of CD31 (as a marker of endothelial cells), vascular endothelial cell growth factor (VEGF), alpha-smooth muscle actin (as a marker of myofibroblasts), heat shock protein 47 (HSP47), type III collagen, F4/80 (as a marker of mice macrophages), proliferating cell nuclear antigen (PCNA), and cyclin-dependent kinase 2 (Cdk2) were examined by immunohistochemistry. RESULTS: CG-injected mice showed thickening of the submesothelial zone and increased number of vessels, myofibroblasts, and infiltrating macrophages. The expression levels of VEGF, type III collagen, and HSP47 were increased, and a large number of PCNA-positive cells and Cdk2-expressing cells were observed in the thickened submesothelial area. Treatment with TNP-470 suppressed the submesothelial zone thickening and reduced collagen III expression as well as angiogenesis. TNP-470 also decreased the number of VEGF-expressing cells, myofibroblasts, macrophages, PCNA-positive cells, and Cdk2-expressing cells. CONCLUSION: Our results indicate the involvement of angiogenesis in the progression of peritoneal fibrosis, and suggest that TNP-470 may be potentially useful for the prevention of peritoneal fibrosis through inhibition of angiogenesis and suppression of myofibroblast proliferation.  相似文献   
90.
BACKGROUND: Activation of protein kinase C (PKC) is a major signaling pathway for transforming growth factor (TGF)-beta to induce extracellular matrix (ECM) production in diabetic nephropathy (DN). PKC also activates mitogen-activated protein kinase (MAPK), which is called the PKC-MAPK pathway. The PKC-MAPK pathway is probably responsible for PKC-related abnormalities in diabetic glomeruli. To confirm the involvement of this pathway, we determined the localization and expression of mRNAs in glomeruli by in situ hybridization method. METHODS: In the present study, we examined expression of PKCbeta1, MAPK/ERK kinase (MEK) 1, MEK2, extracellular signal-regulated protein kinase (ERK) 1, ERK2, and TGF-beta1 mRNAs using renal tissue samples from kidneys affected by DN (N= 21) and from normal human kidney (NHK; N= 6). We also performed an immunohistochemical study using anti-phosphorylated MEK1/2 (P-MEK) and ERK1/2 (P-ERK) antibodies. The glomerular severity of DN was classified into three groups according to mesangial expansion: D1 (N= 4), D2 (N= 13), and D3 (N= 4). We analyzed differences and correlations between variables. RESULTS: In the glomeruli, the number of cells that stained for these mRNAs in DN was significantly higher than in NHK. The expression of PKC-MAPK pathway mRNAs tended to be inversely proportional to the degree of mesangial expansion. The P-MEK and P-ERK signal intensity were parallel to its mRNA expression pattern. Furthermore, there were significant correlations among the P-MEK, P-ERK signal intensity, PKCbeta1 mRNA expression. CONCLUSION: Our results suggest that high expression of PKC-MAPK pathway mRNAs plays an important role in the development and/or progression of early tissue damage in DN.  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