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   6275篇
  免费   699篇
  国内免费   1篇
耳鼻咽喉   155篇
儿科学   401篇
妇产科学   201篇
基础医学   596篇
口腔科学   518篇
临床医学   632篇
内科学   1215篇
皮肤病学   156篇
神经病学   470篇
特种医学   250篇
外科学   1354篇
综合类   24篇
一般理论   1篇
预防医学   264篇
眼科学   169篇
药学   339篇
中国医学   8篇
肿瘤学   222篇
  2023年   138篇
  2022年   64篇
  2021年   195篇
  2020年   165篇
  2019年   198篇
  2018年   406篇
  2017年   314篇
  2016年   399篇
  2015年   390篇
  2014年   406篇
  2013年   802篇
  2012年   336篇
  2011年   339篇
  2010年   408篇
  2009年   214篇
  2008年   111篇
  2007年   40篇
  2006年   188篇
  2005年   121篇
  2004年   51篇
  2003年   49篇
  2002年   65篇
  2001年   129篇
  2000年   102篇
  1999年   125篇
  1998年   131篇
  1997年   102篇
  1996年   131篇
  1995年   84篇
  1994年   96篇
  1993年   78篇
  1992年   57篇
  1991年   58篇
  1990年   43篇
  1989年   27篇
  1988年   34篇
  1987年   16篇
  1986年   30篇
  1985年   23篇
  1984年   27篇
  1983年   22篇
  1982年   27篇
  1981年   26篇
  1980年   23篇
  1979年   22篇
  1978年   9篇
  1977年   9篇
  1976年   11篇
  1974年   8篇
  1973年   9篇
排序方式: 共有6975条查询结果,搜索用时 31 毫秒
61.
Between 1983 and 1993, 41 patients underwent a first-stage Belt-Fuqua operation for penile hypospadias repair and 39 completed the second stage. Minor complications were observed after the first stage. The primary success rate following the second stage was 82%. Major complications noted after the second stage consisted mainly of fistula formation. The surgical technique is described and alternative methods are discussed.  相似文献   
62.
Summary In this experimental study, a neodymiumyttrium-aluminium-garnet (NdYAG) laser was used to induce highly reproducible focal spinal cord lesions in anaesthetized guinea pigs. The efficacy of high dose amino acid solution (HDAAS) on this injury is investigated. Experiments were performed on 36 animals divided into three groups; sham operated controls, laser irradiated surgical controls, and amino acid groups. Acute responses to injury were evaluated with somatosensory (SSEP) and motor evoked potentials (MEP) and functional recovery was assessed for 8 weeks using the inclined plane technique.In the laser irradiated surgical control group, MEP disappeared one hour after the laser injury, but SSEP revealed changes of amplitude and latency. In this group, the average value of the inclined plane at 24 hours after the laser application was 45.3±1.4 degrees. In the amino acid group, at the sixth hour of injury, MEP and SSEP changes improved with infusion of HDAAS for 4 hours. This improvement was statistically significant (for latency of SSEP U=140 p<0.05). Inclined plane value at 24 hours after the laser application was 65.5±1.2 degrees in this group.This study showed that application of NdYAG laser irradiation on the spinal cord induced spinal cord injury which presented as paraparesis, HDAAS may provide significant therapeutic protection in secondary damage following this injury and may have a potential role in the treatment of acute spinal cord injury.  相似文献   
63.
Twenty-seven children with mumps or chickenpox were taken as a model to evaluate the haematological consequences of viral infections including serum iron status. Blood samples were obtained from all patients at presentation and on the 21 st day of the disease. While haemoglobin, haematocrit, and meam corpuscular volume levels were similar in two measurements (P>0.05), the mean leucocyte, absolute lymphocyte and thrombocyte counts, mean serum iron, serum iron binding capacity and transferrin saturation levels were lower at presentation than on the 21 st day of the disease. The serum iron levels were below 30 g/dl in 16 (59.2%) patients at presentation while only 4 (14.8%) had low values on 21 st day. Twenty-four (88.9%) patients had an increment in the serum iron binding capacity levels and 2 (7.6%) reached values above the normal range on the 21 st day. Int 21 (77.8%) patients, the transferrin saturation levels were below the expected ranges at presentation but 26 (96.3%) showed an increment on the 21 st day. However, the mean ferritin level was higher at presentation. Therefore, during the evaluation of patients for anaemia, the presence of a recent acute viral infection should be documented so as to avoid unnecessary iron medication.  相似文献   
64.
It is known that polycythemia decreases the fluidity of the blood and impairs tissue perfusion due to red-cell sludging in the microcirculation. In this study, the effect of polycythemic hyperviscosity (PH) on bowel necrosis was evaluated in an experimental model of intestinal ischemia. Twenty-eight Wistar albino rats (90–170 g) were divided into two groups: group 1 was transfused to create hyperviscosity and then intestinal ischemia was produced (n = 16); in group 2 ischemia was produced without transfusion (n = 12). Intestinal ischemia was produced by clamping the superior mesenteric artery and the collateral arcades of the right colic artery for 30 min. Gross and histopathologic evaluations were performed by either immediate necropsy or relaparotomy 24 h later. Microscopic findings were graded from 0 to 3 according to the degree of ischemic changes. In group 1, 2 animals (12.5%) died before 24 h postoperatively; coagulation necrosis with grade 2 or 3 ischemic changes was observed in 10 animals (62.5%). In group 2 only a few hypertrophied Peyer's patches and capillary dilation were found, and all histopathologic changes were between grades 0 and 1. The difference between the histopathologic gradings of the two groups was significant (P < 0.001). It appears that in addition to reduced splanchnic blood flow, a secondary effect of PH is needed to induce ischemic coagulation necrosis. PH of the newborn must be considered a risk factor for necrotizing enterocolitis, so-called spontaneous intestinal perforations, and even intestinal atresia.Presented at the 1st European Congress of Pediatric Surgery, Graz/Austria, May 4–6, 1995  相似文献   
65.
To understand further the role of trace elements in the pathogenesis of febrile convulsions, serum zinc (Zn), copper (Cu), magnesium (Mg) and CSF Zn, Cu, Mg and protein levels were measured by spectrometry in patients with febrile convulsion (n=19), bacterial meningitis (n=9), viral CNS infection (n=16) and in the control groupn=10) which consisted of children with signs of meningeal irritation due to upper respiratory tract infection but normal CSF findings. Samples were obtained within 6 h after admission to hospital. Mean serum and CSF Zn levels in the febrile convulsion group were significantly lower than in the other groups (for serum Zn: 0.66±0.03 mg/l vs 0.98±0.07 mg/l, 1.06±0.08 mg/l, 1.05±0.09 mg/lP<0.05; for CSF Zn: 22.96±1.62 g/l vs 75.47 ±6.9 g/l, 50.32±5.235 g/l, 39.85 ±2.81 g/lP<0.05). A linear relationship was established between serum Zn and CSF Zn levels (P<0.001). Mean CSF Zn, Cu and protein levels in the bacterial meningitis group were significantly higher than in the other groups (for CSF Cu 63.94±6.33 g/l vs 38.77±2.70 g/l, 35.84±3.48 g/l, 33.86±2.88 g/lP<0.05; for CSF protein 0.80 ± 0.12 g/l vs 0.22±0.02 g/l, 0.53±0.08 g/l, 0.19±0.01 g/lP<0.05). In children with meningitis, the elevation of the mean CSF Zn and Cu levels may result from the breakdown of the blood-brain barrier and subsequent leakage of trace elements and protein from serum to CSF. There was no significant difference between the four groups in terms of mean serum Mg and mean CSF Mg levels.Conclusion Serum and CSF Zn levels are decreased in children with febrile seizures. Zinc deprivation may play a role in the pathogenesis of febrile seizures.  相似文献   
66.
Until recently the only way to rescue masked epitopes in routinely processed surgical pathological material was enzymatic digestion. The use of heat for antigen retrieval, first by microwave irradiation, represents an important breakthrough in immunohistochemistry. With the acceptance of microwave oven pretreatment, various modified techniques and alternative heating methods have also been proposed. Wet autoclave pretreatment for tissue proteolysis is a highly reliable alternative to the microwave antigen retrieval technique. It provides uniform heating of the slides, hence an even enhancement of staining intensity in a variety of formalin-sensitive antigens, and it also offers consistent interlaboratory results. The method has been introduced in routine diagnostic immunohistochemistry for the detection of estrogen-and progesterone receptors, L26-, Ki-67- and bcl-2 antigens and variable types of cytokeratins (1/5/10/11, 8, 13, 19). Experimentally, wet autoclaving can be used very successfully for the immunophenotyping of p53 and mdm2 expression, for the detection of adhesion molecules (CD44, integrins) and some anti-inflammatory molecules (annexins), among others. It has produced a substantial improvement in the visualisation of silver-stained nucleolar organizer regionsassociated proteins (AgNORs) in routine paraffin sections and along with modified silver staining and standardized AgNOR parameters assessed by image analysis. Wet autoclaving-based AgNOR staining has been proposed by a European multicentric study group as the standardized method for AgNOR analysis in archival material.  相似文献   
67.
Formalin fixed and paraffin embedded samples from 36 squamous cell carcinomas of the larynx and the oral cavity (pT2N0M0, R0) surrounded by non-tumorous mucosa were studied immunohistochemically using a panel of four different anti-p53 antibodies (CM1, PAbl801, D07, PAb240), a monoclonal anti-mdm2 antibody and MIB1, following wet autoclave antigen retrieval. P53 immunoreactivity was detected in 11/14 laryngeal and in 9/22 oral carcinomas. All p53 positive oral, and all but one laryngeal tumors revealed mdm2 positivity as well, whereas in p53 negative tumors 4/12 and 1/3 mdm2 immunopositive cases were demonstrated, respectively. MIB1 labeling indices of the tumors ranged between 18% – 64% in p53 positive cases, and 10% – 53% in p53 negative ones. The difference was not statistically significant. Close spatial coexpression of p53, mdm2 and MIB1 immunoreactivity was observed at the invasive front of the carcinomas and in the basal and suprabasal layers of the non-tumorous epithelium in all p53 positive cases. However, the MIB1 expression was similarly increased at the invasive margins in carcinomas lacking immunohistochemically detectable p53 alterations. Our results strongly suggest that p53 overexpression does not necessarily correspond to increased rate of proliferation, but rather to mdm2 overexpression and is largely dependent on the anatomical site in case of small and localized squamous cell carcinomas of the head and neck region.  相似文献   
68.
Hydatid disease is one of the world's most important health problems. Although several conservative approaches have been used for the management of this condition, surgery remains the ideal choice in most of the cases. Videolaparoscopic approach can safely be applied for the management of liver hydatid cysts if several precautions are undertaken. In this study, we present two liver hydatid cyst cases successfully treated with partial cystectomy and omentoplasty using videolaparoscopic approach.  相似文献   
69.
70.
Summary Using the new data from a second followup of the Lundby 1947 cohort, the aim of the present paper has been to analyze some relationships between known and hidden alcoholism in a Swedish general population sample. Information was collected by psychiatrists trough free, exploratory field interviews checked against documentary records. Alcoholism was medically defined for present purposes. Information was obtained for 98% of the 952 men surviving the cross-section date July 1, 1972. The distribution of alcoholism and other psychiatric disorders in the total population and in age subgroups was analyzed epidemiologically. The true prevalence of alcoholism in the adult men was 9.5%, comprising 7.2% known and 2.3% hidden. The proportion of hidden to known cases was 0.301 (Temperance Boards 0.871, Psychiatric Agencies 0.961, Drinking and driving offences 4.31). The main finding that about 70% of male alcoholics in Lundby appears to be known to the agencies is at variance with current views that there is an iceberg under the tip, though consistent with Rubington's suggestion that so-called hidden alcoholism is not totally but partially invisible in welfare societies.  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