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   1856篇
  免费   122篇
  国内免费   64篇
耳鼻咽喉   52篇
儿科学   22篇
妇产科学   20篇
基础医学   264篇
口腔科学   45篇
临床医学   155篇
内科学   312篇
皮肤病学   111篇
神经病学   120篇
特种医学   253篇
外科学   249篇
综合类   10篇
预防医学   61篇
眼科学   36篇
药学   202篇
中国医学   9篇
肿瘤学   121篇
  2023年   10篇
  2022年   32篇
  2021年   79篇
  2020年   46篇
  2019年   49篇
  2018年   74篇
  2017年   45篇
  2016年   77篇
  2015年   97篇
  2014年   114篇
  2013年   85篇
  2012年   165篇
  2011年   125篇
  2010年   95篇
  2009年   76篇
  2008年   115篇
  2007年   131篇
  2006年   91篇
  2005年   75篇
  2004年   68篇
  2003年   55篇
  2002年   39篇
  2001年   51篇
  2000年   54篇
  1999年   37篇
  1998年   21篇
  1997年   16篇
  1996年   16篇
  1995年   9篇
  1994年   7篇
  1993年   12篇
  1992年   8篇
  1991年   11篇
  1990年   7篇
  1989年   7篇
  1988年   9篇
  1987年   7篇
  1986年   3篇
  1985年   3篇
  1984年   3篇
  1983年   4篇
  1982年   4篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1970年   1篇
  1969年   2篇
排序方式: 共有2042条查询结果,搜索用时 15 毫秒
71.
The role played by spinal adrenergic and cholinergic receptors in the antinociceptive effects of intrathecal sildenafil in formalin-induced nociception was examined. Intrathecal catheters were inserted into the subarachnoid space of male Sprague-Dawley rats, and nociception was assessed using the formalin test, consisting of a subcutaneous injection of 50 μL of 5% formalin solution into the hind paw. We examined the effects of an alpha 1 adrenergic receptor antagonist (prazosin), an alpha 2 adrenergic receptor antagonist (yohimbine), a muscarinic acetylcholine receptor antagonist (atropine), and a nicotinic acetylcholine receptor antagonist (mecamylamine) on sildenafil-induced antinociception. Intrathecal sildenafil (3, 10, and 30 μg) suppressed, in a dose-dependent manner, formalin-induced flinching during phases 1 and 2 of the test. Intrathecal sildenafil (30 μg) could not show any effects against intrathecal prazosin (3 μg), yohimbine (10 μg), atropine (10 μg), and mecamylamine (10 μg) pretreatment during both phases of the formalin test. These results suggest that intrathecal sildenafil effectively attenuated the pain evoked by formalin injection. Additionally, spinal alpha 1, alpha 2, muscarinic and nicotinic receptors might play a role in sildenafil-induced antinociception.  相似文献   
72.
A 58‐year‐old woman complained of painless jaundice. The serology showed total bilirubin 10.6 mg/dL with direct bilirubin of 7.0 mg/dL. Abdominal computed tomography (CT) scan disclosed an abnormal arrangement of the abdominal viscera and dilation of the biliary tree. A nearly 1.4 cm‐sized periampullary mass was seen. These findings are compatible with situs ambiguous with polysplenia and were suggestive of a periampullary tumor. Due to her unusual anatomical features, the patient underwent an endoscopic retrograde cholangiopancreatography (ERCP) in the supine position instead of in the conventional prone position. ERCP showed that the common bile duct (CBD) diameter was increased to 20 mm. Microscopic findings of the biopsy specimen of papillary mass were compatible with an adenocarcinoma of the ampulla of Vater. The clinical stage was stage IA (T1N0M0). Eight days later, a papillectomy was carried out by endoscopic snare resection. Six months later, follow‐up studies, including ERCP, abdominal CT and 18‐fluorodeoxyglucose positron emission tomography (18‐FDG PET)‐CT scan, showed no evidence of recurrence. Although the success rate of supine position ERCP may be influenced by the extent of the intestinal malrotation and the position of the duodenum, we conclude that supine position ERCP can be carried out effectively in a patient with situs anomaly.  相似文献   
73.
Autosomal recessive nonsyndromic hearing impairment (ARNSHI) segregating in three unrelated, large consanguineous Pakistani families (PKDF528, PKDF859 and PKDF326) is linked to markers on chromosome 12q14.2-q15. This novel locus is designated DFNB74 . Maximum two-point limit of detection (LOD) scores of 5.6, 5.7 and 2.6 were estimated for markers D 12 S 313, D 12 S 83 and D 12 S 75 at θ = 0 for recessive deafness segregating in these three families. Haplotype analyses identified a critical linkage interval of 5.35 cM (5.36 Mb) defined by D 12 S 329 at 74.58 cM and D 12 S 313 at 79.93 cM. DFNB74 is the second ARNSHI locus mapped to chromosome 12, but the physical intervals do not overlap with one another. A locus contributing to the early onset, rapidly progressing hearing loss of A/J mice ( ahl4 , age-related hearing loss 4) was reported to map to chromosome 10 in a region of conserved synteny to DFNB74 , suggesting that ahl4 and DFNB74 may be due to mutations of the same gene in these two species.  相似文献   
74.
Variants in the amino acid composition of the primary antibody-binding site of hepatitis B surface antigen (HBsAg) have been identified in a number of populations with chronic hepatitis B virus (HBV) infection. Direct sequencing of amplified or cloned PCR products, solid phase detection of sequence-specific PCR products (SP-PCR), and limiting dilution cloning PCR (LDC-PCR) were compared to determine their sensitivity in detecting differing concentrations of HBsAg variants. LDC-PCR had the greatest sensitivity and could detect HBsAg variants at a concentration of 0.1% of the total viral population. HBsAg variants were detected in 51% of infants with chronic HBV infection acquired after postexposure prophylaxis, and more than half of the variants were detected only by the most sensitive methods.  相似文献   
75.
Advanced glycation end products (AGEs) are associated with the pathogenesis of various diseases. AGEs induce excess accumulation of extracellular matrix and expression of profibrotic cytokines. In addition, studies on receptor for advanced glycation end products (RAGE) have shown that the ligand-RAGE interaction activates several intracellular signaling cascades associated with several fibrotic diseases. We investigated the expression of AGEs and RAGE in samples from patients with idiopathic pulmonary fibrosis (IPF) and non-specific interstitial pneumonia (NSIP). Lung tissues and plasma samples from patients with IPF (n=10), NSIP (n=10), and control subjects (n=10) were obtained. Expression of AGEs and RAGE was determined by immunofluorescence assay of lung tissue. Circulating AGEs were measured by Western blot and enzyme-linked immunosorbent assay. Lungs with IPF showed strong expression for both AGEs and RAGE compared to that in NSIP and controls. However, no difference in AGE or RAGE expression was observed in lungs with NSIP compared to that in the controls. Levels of circulating AGEs also increased significantly in lungs of patients with IPF compared to those with NSIP and normal control. Increased AGE-RAGE interaction may play an important role in the pathogenesis of IPF.  相似文献   
76.
An 84-year-old man was admitted to our hospital with fever, jaundice, and itching. He had been diagnosed previously with chronic renal failure and diabetes, and had been taking allopurinol medication for 2 months. A physical examination revealed that he had a fever (38.8℃), jaundice, and a generalized maculopapular rash. Azotemia, eosinophilia, atypical lymphocytosis, elevation of liver enzymes, and hyperbilirubinemia were detected by blood analysis. Magnetic resonance cholangiography revealed multiple cysts similar to choledochal cysts in the liver along the biliary tree. Obstructive jaundice was suspected clinically, and so an endoscopic ultrasound examination was performed, which ruled out a diagnosis of obstructive jaundice. The patient was diagnosed with DRESS (Drug Rash with Eosinophilia and Systemic Symptoms) syndrome due to allopurinol. Allopurinol treatment was stopped and steroid treatment was started. The patient died from cardiac arrest on day 15 following admission.  相似文献   
77.
Studies have found an association between aberrant DNA methylation and arsenic‐induced skin lesions. However, little is known about DNA methylation changes over time in people who develop arsenic‐induced skin lesions. We sought to investigate epigenome‐wide changes of DNA methylation in people who developed arsenic‐induced skin lesions in a 10‐year period. In 2009–2011, we conducted a follow‐up study of 900 skin lesion cases and 900 controls and identified 10 people who developed skin lesions since a baseline survey in 2001–2003. The 10 cases (“New Cases”) were matched with 10 controls who did not have skin lesions at baseline or follow‐up (“Persistent Controls”). Drinking water and blood samples were collected, and skin lesion was diagnosed by the same physician at both time points. We measured DNA methylation in blood using Infinium HumanMethylation450K BeadChip, followed by quantitative validation using pyrosequencing. Two‐sample t‐tests were used to compare changes in percent methylation between New Cases and Persistent Controls. Six CpG (cytosine‐phosphate‐guanine) sites with greatest changes of DNA methylation over time among New Cases were further validated with a correlation of 93% using pyrosequencing. One of the validated CpG site (cg03333116; change of %methylation was 13.2 in New Cases versus ?0.09 in Persistent Controls; P < 0.001) belonged to the RHBDF1 gene, which was previously reported to be hypermethylated in arsenic‐exposed cases. We examined DNA methylation changes with the development of arsenic‐induced skin lesions over time but nothing was statistically significant given the small sample size of this exploratory study and the high dimensionality of data. Environ. Mol. Mutagen. 55:449–456, 2014. © 2014 Wiley Periodicals, Inc.  相似文献   
78.
79.
Various types of diseases can involve the nasal vestibule. Diagnosis and treatment of a nasal vestibular mass is often challenging due to the anatomical features of the nasal vestibule. Here, we present four cases with nasal vestibular masses. Two cases were diagnosed as squamous papillomas. The others were a trichofolliculoma and pseudoepitheliomatous hyperplasia with hyperkeratosis. Our aim was to discuss the characteristics of each disease and the considerations thought to be necessary for diagnosis and treatment of nasal vestibular tumors from these cases and the related literature.  相似文献   
80.
We report a rare case of early-stage endometrial adenocarcinoma in a 22 year old nullipara with polycystic ovaries undergoing conservative treatment. Pretreatment evaluation including tumour grade, depth of myometrial invasion, tumour size, hormone receptor status and flow cytometric analysis indicated a favourable prognosis. The patient underwent repeat endometrial curettage and a 6 month period of therapy with megestrol acetate and tamoxifen. A combination contraceptive pill was then prescribed to ensure withdrawal of the menstrual cycle thereafter. Now, 1 year after the last curettage, there is no evidence of disease. During the treatment period, hysteroscopy allowed for a more precise approach in panoramically examining the tumour nest in the endometrial cavity, and the subsequent endometrial response to hormone therapy. Laparoscopy using bulldog clamps applied to the isthmic portion of the Fallopian tubes prevented i.p. spread of endometrial tissue from retrograde regurgitation during hysteroscopy. Laparoscopic ovarian electrocautery resulted in the reduction of abnormal hypervascularization on the surface of polycystic ovaries postoperatively but caused a peri-ovarian adhesion complication. It is interesting that this case posed a unique opportunity to demonstrate the tumour regression under the assistance of laparoscopy and hysteroscopy.   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