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   3131篇
  免费   193篇
  国内免费   14篇
耳鼻咽喉   106篇
儿科学   161篇
妇产科学   70篇
基础医学   491篇
口腔科学   37篇
临床医学   142篇
内科学   626篇
皮肤病学   48篇
神经病学   244篇
特种医学   66篇
外科学   262篇
综合类   18篇
预防医学   318篇
眼科学   63篇
药学   426篇
中国医学   11篇
肿瘤学   249篇
  2023年   18篇
  2022年   57篇
  2021年   107篇
  2020年   69篇
  2019年   81篇
  2018年   156篇
  2017年   131篇
  2016年   127篇
  2015年   130篇
  2014年   214篇
  2013年   259篇
  2012年   340篇
  2011年   374篇
  2010年   193篇
  2009年   109篇
  2008年   119篇
  2007年   143篇
  2006年   149篇
  2005年   93篇
  2004年   97篇
  2003年   68篇
  2002年   86篇
  2001年   15篇
  2000年   7篇
  1999年   13篇
  1998年   13篇
  1997年   10篇
  1996年   11篇
  1995年   5篇
  1994年   11篇
  1992年   5篇
  1989年   6篇
  1988年   7篇
  1986年   4篇
  1985年   5篇
  1984年   4篇
  1983年   8篇
  1982年   4篇
  1981年   9篇
  1980年   10篇
  1979年   6篇
  1978年   7篇
  1977年   10篇
  1976年   8篇
  1975年   6篇
  1974年   4篇
  1973年   3篇
  1972年   3篇
  1971年   3篇
  1969年   4篇
排序方式: 共有3338条查询结果,搜索用时 54 毫秒
81.
82.

Aims

The level of C-peptide can identify individuals most likely to respond to immune interventions carried out to prevent pancreatic β-cell damage.The aim of the study was to evaluate factors associated with C-peptide levels at type 1 diabetes (T1D) diagnosis.

Methods

This study included 1098 children aged 2-17 with newly recognized T1D. Data were collected from seven Polish hospitals. The following variables were analyzed: date of birth, fasting C-peptide, HbA1c, sex, weight, height, pH at diabetes onset.

Results

A correlation was observed between fasting C-peptide level and BMI-SDS (p?=?0.0001), age (p?=?0.0001), and HbA1c (p?=?0.0001). The logistic regression model revealed that fasting C-peptide ≥0.7 ng/ml at diabetes diagnosis was dependent on weight, HbA1c, pH and sex (p?<?0.0001).Overweight and obese children (n?=?124) had higher fasting C-peptide (p?=?0.0001) and lower HbA1c (p?=?0.0008) levels than other subjects. Girls had higher fasting C-peptide (p?=?0.036) and higher HbA1c (p?=?0.026) levels than boys.

Conclusion

Obese and overweight children are diagnosed with diabetes at an early stage with largely preserved C-peptide levels. Increased awareness of T1D symptoms as well as improved screening and diagnostic tools are important to preserve C-peptide levels. There are noticeable gender differences in the course of diabetes already at T1D diagnosis.  相似文献   
83.
84.
85.
Infections that are triggered by the accompanying immunosuppression in patients with burn wounds are very common regardless of age. Among burn patients, the most frequently diagnosed infections include the bacterial ones primarily caused by Pseudomonas aeruginosa or Klebsiella pneumonia, as well as fungal infections with the etiology of Candida spp. or Aspergillus spp. Besides, burn wounds are highly susceptible to viral infections mainly due to the impaired immune responses and defective functions of the immune cells within the wound microenvironment. The most prevalent viruses that invade burn wounds include herpes simplex virus (HSV), cytomegalovirus (CMV), human papilloma virus (HPV), and varicella zoster virus (VZV). Likewise, less prevalent infections such as those caused by the orf virus or Epstein–Barr Virus (EBV) might also occur in immunosuppressed burn patients. Viral infections result in increased morbidity and mortality rates in severely burned patients. Additionally, a positive correlation between the hospitalization duration and the severity of the viral infection has been demonstrated. Viral infections trigger the occurrence of various complications, ranging from mild symptoms to even fatal incidents. Accurate detection of viral infection is of great clinical importance because of the possibility for a quicker introduction of proper treatment therapy and shortening of hospitalization time. The aim of this paper is to provide a comprehensive review of the literature and summarize the findings regarding the most common viral infections in immunosuppressed burn patients.  相似文献   
86.
The aim of the study was to determine the prevalence of Echinococcus multilocularis in red foxes (Vulpes vulpes) in Poland. Overall, 1,546 intestinal samples from 15 of the 16 provinces in Poland were examined by the sedimentation and counting technique (SCT). The mean prevalence of E. multilocularis in Poland was 16.5 % and was found in 14 of the 15 examined provinces. The mean intensity of infection was 2,807 tapeworms per intestine. Distinct differences in prevalence were observed between regions. In some provinces of eastern and southern Poland, the level of prevalence was 50.0 % (Warmińsko-Mazurskie), 47.2 % (Podkarpackie), 30.4 % (Podlaskie) and 28.6 % (Ma?opolskie), while in other provinces (west and south-west), only a few percent was found: 2.0 % (Dolno?l?skie), 2.5 % (Wielkopolskie) and 0.0 % (in Opolskie). The border between areas with higher and lower prevalence seems to coincide with a north–south line running through the middle of Poland, with prevalence from 17.5 to 50.0 % in the eastern half and from 0.0 to 11.8 % in the western half. The dynamic situation observed in the prevalence of this tapeworm indicated the necessity of continuing to monitor the situation concerning E. multilocularis in red foxes in Poland.  相似文献   
87.
Polysulfone‐based membranes with excellent chemical resistance and a wet thickness up to 200 μm are obtained via UV curing of unmodified polymers after careful tuning of the photoinitiating system and the crosslinker structure. Combinations of photoinitiator and crosslinker are studied in depth, followed by a characterization of the formed macromolecular structure. The performance of the resulting membranes is then evaluated through long‐term immersion in solvents. Classical depth‐curing acyl phosphine oxide‐based photoinitiators in combination with a pentaacrylate crosslinker are found to be the optimal system.

  相似文献   

88.
The risk of developing papillary thyroid carcinoma (PTC), the most frequent form of thyroid malignancy, is elevated up to 8.6‐fold in first‐degree relatives of PTC patients. The familial risk could be explained by high‐penetrance mutations in yet unidentified genes, or polygenic action of low‐penetrance alleles. Since the DNA‐damaging exposure to ionizing radiation is a known risk factor for thyroid cancer, polymorphisms in DNA repair genes are likely to affect this risk. In a search for low‐penetrance susceptibility alleles we employed Sequenom technology to genotype deleterious polymorphisms in ATM, CHEK2, and BRCA1 in 1,781 PTC patients and 2,081 healthy controls. As a result of the study, we identified CHEK2 rs17879961 (OR = 2.2, P = 2.37e‐10) and BRCA1 rs16941 (odds ratio [OR] = 1.16, P = 0.005) as risk alleles for PTC. The ATM rs1801516 variant modifies the risk associated with the BRCA1 variant by 0.78 (P = 0.02). Both the ATM and BRCA1 variants modify the impact of male gender on clinical variables: T status (P = 0.007), N status (P = 0.05), and stage (P = 0.035). Our findings implicate an important role of variants in the ATM‐ CHEK2‐ BRCA1 axis in modification of the genetic predisposition to PTC and its clinical manifestations. © 2014 Wiley Periodicals, Inc.  相似文献   
89.
BackgroundSynthetic cathinones (SCs) form one of the most prominent group of the New Psychoactive Substances. SCs enhance central dopaminergic and noradrenergic neurotransmission, and are used as substitutes for illicit psychostimulants, namely cocaine, amphetamine, and methamphetamine. Changes in the expression of immediate early genes (IEGs) in the striatum underlie the addictive potential of drugs of abuse belonging to distinct pharmacologic groups. This work was aimed to assess the impact of acute administration of the prominent SCs on the mRNA levels of IEGs in the mouse striatum.MethodsEffects of 3,4-MDPV, 2,3-MDPV, α-PVP, PV8, PV9, methcathinone (MC) and 3-fluoromethcathinone (3-FMC) on the mRNA levels of ten IEGs, one and two hours after exposure, were measured in the mouse striatum using the quantitative RT-PCR technique.ResultsAll SCs used in the study produced increased mRNA levels of the following IEGs: Areg, c-fos, Csrnp1, Dusp1, Dusp14, Egr2, Egr4 and FosB. Additionally, the majority of SCs increased the expression of Homer1 and c-jun. The magnitude of observed changes varied by the drug, analyzed gene and, in many cases, by time after administration.ConclusionsThis study demonstrates that SCs increase the expression of IEGs in the mouse striatum, which may lead to a plethora of effects, as proteins encoded by the analyzed genes are involved in diverse actions, including an acute response to the drug and the neuroplasticity underlying the development of addiction.  相似文献   
90.
AIM: To determine the prevalence and characteristics of additional primary malignancies in gastric cancer (GC) patients.METHODS: GC patients (862 total; 570 men, 292 women; mean age 59.8 ± 12.8 years) diagnosed at the Department of Gastroenterology at Pomeranian Medical University over a period of 23 years were included in this retrospective analysis of a prospectively maintained database. Mean follow-up time was 31.3 ± 38.6 mo (range 1-241 mo). The following clinicopathological features of patients with synchronous tumors were compared to those with metachronous tumors: age, sex, symptom duration, family history of cancer, tumor site, stage (early vs advanced), histology, and blood group. GC patients with and without a second tumor were compared in terms of the same clinicopathological features.RESULTS: Of 862 GC patients, 58 (6.7%) developed a total of 62 multiple primary tumors, of which 39 (63%) were metachronous and 23 (37%) synchronous. Four (6.9%) of the 58 multiple GC patients developed two or more neoplasms. The predominant tumor type of the secondary neoplasms was colorectal (n = 17), followed by lung (n = 9), breast (n = 8), and prostate (n = 7). Age was the only clinicopathological feature that differed between GC patients with synchronous vs metachronous malignancies; GC patients with synchronous neoplasms were older than those with metachronous neoplasms (68.0 ± 10.3 years vs 59.9 ± 11.1 years, respectively, P = 0.008). Comparisons between patients with and without a second primary cancer revealed that the only statistically significant differences were in age and blood group. The mean age of the patients with multiple GC was higher than that of those without a second primary tumor (63.4 ± 11.4 years vs 59.5 ± 13.0 years, respectively, P = 0.026). GC patients with a second primary tumor were more commonly blood group O than those without (56.2% vs 31.6%, respectively, P = 0.002).CONCLUSION: GC patients may develop other primary cancers; appropriate preoperative and postoperative diagnostic modalities are thus required, particularly if patients are older and blood group O.  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