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   1102篇
  免费   89篇
  国内免费   4篇
耳鼻咽喉   13篇
儿科学   52篇
妇产科学   41篇
基础医学   198篇
口腔科学   46篇
临床医学   117篇
内科学   228篇
皮肤病学   13篇
神经病学   98篇
特种医学   12篇
外科学   78篇
综合类   12篇
预防医学   75篇
眼科学   58篇
药学   85篇
中国医学   9篇
肿瘤学   60篇
  2024年   4篇
  2023年   21篇
  2022年   55篇
  2021年   53篇
  2020年   45篇
  2019年   66篇
  2018年   76篇
  2017年   67篇
  2016年   63篇
  2015年   66篇
  2014年   59篇
  2013年   82篇
  2012年   116篇
  2011年   103篇
  2010年   57篇
  2009年   39篇
  2008年   60篇
  2007年   47篇
  2006年   39篇
  2005年   20篇
  2004年   24篇
  2003年   15篇
  2002年   6篇
  2001年   5篇
  2000年   1篇
  1999年   1篇
  1996年   1篇
  1994年   1篇
  1988年   1篇
  1982年   1篇
  1981年   1篇
排序方式: 共有1195条查询结果,搜索用时 10 毫秒
61.
Aim of this study was to evaluate the prevalence of suicide ideation and behavior in a community sample of an Iranian city, Karaj. Study sample consisted of 2,300 subjects, chosen randomly from the community. The WHO/SUPRE-MISS survey questionnaire, used in this study. Lifetime prevalence for suicide thoughts, plans and attempts were 12.7, 6.2 and 3.3%, respectively and for the previous year they were 5.7, 2.9 and 1%, respectively. Although it is not possible to generalize the results to the country, but in some area of Iran, the prevalence of suicide ideation, plan and attempt appeared to be similar to that of many developed countries.  相似文献   
62.
Keratoacanthomas are commonly occurring benign skin lesions localized to sun-exposed areas. They typically develop rapidly and may show cellular atypia and infiltration like cutaneous squamous cell carcinomas, but they finally regress spontaneously. This benign lesion shows a high degree of genetic instability as assessed by comparative genomic hybridization, with 35.7% (25 of 70) of the analyzed lesions harboring chromosomal aberrations. The same frequency of genetic imbalance was found in lesions from immunosuppressed organ transplant recipients (36.4%, 20 of 55) and in patients with keratoacanthomas without immunosuppression (33.3%, five of 15), indicating a common pathway in both situations. Recurrent aberrations, given as a fraction of lesions with aberrations, were gains on 8q (20.0%), 1p and 9q (each 16.0%), and deletions on 3p (20.0%), 9p (20.0%), 19p (20.0%), and 19q (16.0%). Many of the most frequently appearing aberrations in keratoacanthomas were not detected in any of the 10 squamous cell carcinomas analyzed, whereas some aberrations were shared by both types of lesions. Aberrations were found in early and late stages of keratoacanthoma development, indicating a role for genetic instability in the progression as well as involution of keratoacanthomas. There were no significant correlations between cytologic atypia and genetic imbalance, or between degree of infiltration and genetic aberrations, although there was a trend for keratoacanthomas with severe atypia to have aberrations. Thus malignant phenotypic development does not appear to be driven by the detected genetic aberrations. More detailed studies of chromosomal areas with recurrent aberrations are needed for the localization of putative genes that determine the biologic behavior of keratoacanthomas, and that may distinguish them from squamous cell carcinomas.  相似文献   
63.
To determine the domains essential for G-protein coupling of the human galanin receptor type 1 (GalR1), we have used both GalR1 mutants and synthetic receptor-derived peptides in(125)I-galanin and [(35)S]-GTPgammaS binding studies. Replacement of potential phosphorylation sites by Leu in the third intracellular loop (IC3) of GalR1 did not affect K(D)values for the receptor. Peptides derived form the IC3 loop, and especially the N-terminal part of it were able to increase the rate of [(35)S]-GTPgammaS binding to the trimeric Gialpha1beta1gamma2, but not to Gsalphabeta1gamma2, whereas the peptides corresponding to the IC1 and IC2 loops had no such effect. IC3 loop peptides also inhibited the binding of(125)I-galanin to GalR1 in membranes from Rin m5F cells. Our results suggest that the IC3 loop of GalR1, especially its N-terminal part, defines the coupling of the receptor to the Gialpha1beta1gamma2 protein and consequently, to the signal transduction cascade.  相似文献   
64.
A six-year study on Vibrio cholerae in southeastern Iran   总被引:1,自引:0,他引:1  
Cholera continues to be an important public health problem among many poorer communities. In order to determine the epidemiology of Vibrio cholerae in southeastern Iran, 3,594 patients with watery diarrhea, who were referred to the hospitals from Zabol city and 45 neighboring rural populations of Sistan-Blouchestan province, were investigated over a period of 6 years (1997 - 2002). V. cholerae strains were isolated from 362 samples (10.07%). Isolation of V. cholerae in this sample decreased from 22.47% in 1997 to 0% in 2002. Individuals of all ages and social and economic strata were affected. Among the patients with cholera in the present study, only 24 (6.6%) lived in an urban area; 270 (74.6%) of the patients had been referred from rural areas, and the remaining 68 (18.8%) were from neighboring Afghanistan. V. cholerae O1 Ogawa and NAG vibrios were found in 92.8 and 7.2% of patients, respectively. Among the 362 samples, 244 were collected from inpatients and 118 were from outpatients. Twelve of these patients died because of the severity of their disease, severe dehydration and electrolytes imbalance. The priorities for cholera control remain public health interventions through improved water and sanitation, improved surveillance and access to health care facilities, and further development of appropriate vaccines.  相似文献   
65.
Allgrove syndrome is a genetic disorder inherited in an autosomal recessive pattern and characterized by a triad of adrenal insufficiency, achalasia, and alacrima. The gene affected by the mutation in patients with Allgrove syndrome is termed either AAAS or ALADIN (alacrima/achalasia/adrenal insufficiency/neurologic disorder). Adrenal insufficiency in patients with this disorder may develop as late as the third decade of life. We describe a 24-year-old female with Allgrove syndrome, in whom initial testing with 250 microg corticotropin (ACTH) stimulation test performed on 3 occasions produced normal serum cortisol values and results of the 1-microg ACTH stimulation tests performed on 6 occasions were conflicting. Insulin-induced hypoglycemia produced a nadir serum glucose value of 36 mg/dL without adequate serum cortisol stimulation, confirming presence of adrenal insufficiency. Gene sequencing identified 2 mutations in the triple A gene: an IVSC14 + 1 G to A mutation, which has been previously reported, and a novel R155P exon 6 mutation. We conclude that a novel R155P mutation in the ALADIN gene is associated with Allgrove syndrome and that insulin-induced hypoglycemia, rather than ACTH stimulation tests, should be used for accurate diagnosis of adrenal insufficiency in this disorder.  相似文献   
66.
Brain metastasis from esophageal carcinoma is rare. In our center, among 301 cases of esophageal cancer referred for radiotherapy during a 14-year period, brain metastasis from esophageal carcinoma was detected in one case. An unusual case of esophageal carcinoma that presented with brain metastasis is reported.  相似文献   
67.
The study was carried out to determine the prevalence and pattern of antimicrobial resistance of Shigella species among patients with acute diarrhoea in Karaj, Tehran, Iran. The study included all acute diarrhoea patients who visited the hospitals and treatment centres of Karaj during November 2001-October 2002. Of 734 stool samples collected from patients with acute diarrhoea and analyzed for Shigella spp., 123 (16.8%) yielded Shigella spp. (7.5% Shigella flexneri, 5.2% S. sonnei, 2.6% S. dysenteriae, and 1.5% S. boydii). Of the Shigella isolates, 90.8% were resistant to one or more antimicrobial agent(s), and 87.8% were multidrug resistant. The most common resistance was to tetracycline (73.5%), trimethoprim-sulphamethoxazole (70.4%), and amoxicillin-clavulanic acid (50.0%). Resistance to cefixime, ciprofloxacin, ceftriaxone, and nalidixic acid was observed in 6.1%, 3.1%, 2.0%, and 1.0% of the isolates respectively. These findings suggest that Shigella spp. may be an important aetiological agent of diarrhoea with a high rate of drug resistance in this region, which requires further study.  相似文献   
68.
Background: Isolated limb perfusion (ILP) with recombinant human tumor necrosis factor- (rhTNF-) and melphalan harbors the risk of septic shock–like syndrome. Pentoxifyllin (PTX) produced a beneficial effect on cytokine response and survival in animal experiments of septic shock, and we were interested to explore its effect during TNF-ILP in humans.Methods: Eighteen consecutive patients underwent TNF-ILP and received PTX (30 mg/kg/day), whereas another 13 consecutive patients did not. PTX was given systemically after the limb extracorporeal circulation was started. Cardiac index, systemic vascular resistance (SVR), and pulmonary vascular resistance were recorded via a Swan-Ganz catheter. Blood levels of TNF-, interleukin-6, procalcitonin, and lipopolysaccharide-binding protein were determined before, during, and after ILP.Results: After reperfusion, systemic levels of TNF- were significantly less increased in the PTX group (peak, 2.8 vs. 1.3 ng/mL; P < .05), as were interleukin-6 values (peak, 68 vs. 22 pg/mL; P < .02) and lipopolysaccharide-binding protein plasma levels (peak, 215 vs. 105 g/mL; P < .03). Differences in cardiac index, SVR, and mean arterial blood pressure were not significantly different. Norepinephrine or dobutamine to maintain SVR was less required in the PTX group.Conclusions: PTX attenuates systemic cytokine production and influences components of the systemic inflammatory response after TNF-ILP. PTX may play a beneficial role in the management of septic shock–like syndrome, particularly in patients with leakage from the ILP circuit.Presented at the 55th Annual Meeting of the Society of Surgical Oncology, Denver, Colorado, March 14–17, 2002.  相似文献   
69.
Peptide nucleic acids (PNA) are nucleic acid analogues containing neutral amide backbone, forming stable and tight complexes with complementary DNA/RNA. However, it is unclear whether unmodified PNA can efficiently penetrate neuronal tissue in order to act as antisense reagent. Here we show that intrathecal (i.t.) injection of an unmodified antisense PNA complementary to the rat galanin receptor type 1 (GalR1) mRNA is able to block the inhibitory effect of i.t. administered galanin on spinal nociceptive transmission. Autoradiographic ligand binding studies using [125I]galanin show that the unmodified PNA is able to reduce the density of galanin binding sites in the dorsal horn. Thus, unmodified PNA applied i.t. appears to function as an effective antisense reagent in rat spinal cord in vivo.  相似文献   
70.

Background  

Sleep patterns and habits in high school students in Iran have not been well studied to date. This paper aims to re-address this balance and analyse sleep patterns and habits in Iranian children of high school age.  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