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   3673篇
  免费   192篇
  国内免费   16篇
耳鼻咽喉   22篇
儿科学   215篇
妇产科学   69篇
基础医学   407篇
口腔科学   40篇
临床医学   217篇
内科学   929篇
皮肤病学   61篇
神经病学   312篇
特种医学   90篇
外科学   436篇
综合类   147篇
一般理论   1篇
预防医学   287篇
眼科学   78篇
药学   330篇
中国医学   9篇
肿瘤学   231篇
  2023年   20篇
  2022年   28篇
  2021年   88篇
  2020年   49篇
  2019年   51篇
  2018年   78篇
  2017年   60篇
  2016年   64篇
  2015年   48篇
  2014年   70篇
  2013年   129篇
  2012年   174篇
  2011年   228篇
  2010年   119篇
  2009年   136篇
  2008年   211篇
  2007年   166篇
  2006年   155篇
  2005年   134篇
  2004年   166篇
  2003年   145篇
  2002年   118篇
  2001年   102篇
  2000年   91篇
  1999年   88篇
  1998年   49篇
  1997年   33篇
  1996年   38篇
  1995年   19篇
  1994年   29篇
  1992年   55篇
  1991年   52篇
  1990年   60篇
  1989年   74篇
  1988年   65篇
  1987年   58篇
  1986年   44篇
  1985年   55篇
  1984年   40篇
  1983年   40篇
  1980年   25篇
  1979年   35篇
  1978年   22篇
  1977年   27篇
  1976年   24篇
  1975年   27篇
  1974年   26篇
  1973年   32篇
  1972年   26篇
  1971年   20篇
排序方式: 共有3881条查询结果,搜索用时 31 毫秒
111.

Background

Neonatal birth weight is a powerful predictor of infant growth and survival and maternal factors like poor knowledge and insufficient dietary intake are significant risk factors. Other preventable determinants like pre pregnant BMI <18.5, low gestational weight gain (GWG) and anemia are also associated with low birth weight. This study was carried out to identify the impact of these maternal factors with risk of low birth weight (LBW).

Methods

A longitudinal study was carried out on 124 booked antenatal cases at a tertiary care center. A validated protocol containing socio demography, food frequency and anthropometry was administered at the 3rd trimester. Birth weight of the newborn was noted after delivery.

Results

26.28% children had low birth weight (<2500 g), 14.6% mothers were thin (BMI < 18.5), 55.3% mothers had a weight gain of less than 9 kgs and 45.5% were anemic. 81.81% mothers with BMI >18.5 and 28.92% women who were educated till high school had a baby with LBW. Most mothers consumed milk and vegetables daily and a few consumed non vegetarian foods but quality and quantity of food were grossly inadequate. GWG levels and Hb levels were significantly different in different birth weight groups and also were significantly associated with low birth weight.

Conclusion

Quality and quantity of maternal dietary intake during pregnancy, even in normal weight mothers (BMI > 18.5), are important determinants of birth weight. Nutritional counseling for mothers during the antenatal period is the cornerstone for healthy mother and healthy child.  相似文献   
112.
113.

Background and Aims:

Group A Streptococcus (GAS) can cause illnesses ranging from self-limited to severe, life-threatening, invasive infections. The objective of the following study was to investigate a suspected Streptococcus pyogenes outbreak in a high dependency unit (HDU) of our trauma center.

Materials and Methods:

All the isolates of beta hemolytic Streptococci were identified by standard microbiological methods, Vitek 2 system and latex agglutination tests. Antimicrobial susceptibility testing was performed as recommended by Clinical Laboratory Standards Institute. Exotoxin genes, including speA, speB, speC, speF, smeZ, ssa, speG, speH, speJ, speL, speM and speI were detected by polymerase chain reaction (PCR). The emm types of isolates of S. pyogenes were determined by sequencing the variable 5’ end of emm gene after amplification by PCR.

Results:

In a 28 bedded poly-trauma ward with a four bedded HDU three out of four patients developed S. pyogenes emm type 58 infection. The strain was macrolide and tetracycline resistant and produced the Streptococcal pyrogenic exotoxins speB, speC, speG, speF and smeZ. Surveillance sampling was done for investigation from patients, health-care workers and environmental samples.

Conclusion:

An outbreak of GAS infections was established caused by the uncommonly reported emm type 58. The outbreak was controlled by prompt treatment, intensive surveillance, feedback and training.  相似文献   
114.
115.
Cushing's syndrome (CS) is associated with increased cardiovascular morbidity and mortality. Recent evidence also suggests that increased cardiovascular risk may persist even after long-term remission of CS. Increased central obesity, a typical feature of CS, is associated with altered production of adipokines, which contributes to the pathogenesis of several metabolic and cardiovascular complications observed in this condition. In vitro and in vivo studies have shown a relationship between cortisol and adipokines in several experimental settings. In patients with either active or 'cured' CS, an increase in leptin and resistin levels as well as the release of pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-6, may be associated with increased cardiovascular risk. For other adipokines, including adiponectin, results are inconclusive. Studies are needed to further elucidate the interactions between clinical and subclinical increases in cortisol production and altered adipokine release in CS.  相似文献   
116.
117.

Background

Helicobacter species have been found to be associated with biliary tract diseases. This prospective study was done to determine the prevalence of H. pylori in the biliary tract of patients suffering from gallbladder disease.

Methods

Forty-nine patients undergoing laparoscopic/open cholecystectomy for benign biliary tract diseases were investigated with urea breath test for H. pylori infection of gastric antrum. Bile and gallbladder tissues were studied for presence of H. pylori by rapid urease test, histopathological examination, culture and PCR analysis. Gallbladder specimens from two patients who underwent Whipple??s operation and from 10 cadavers were studied as controls.

Results

The mean (SD) age of patients was 42.4 (11.1) years. Urea breath test was positive in 17 (34.6%) cases. Rapid urease test was negative in all the cases. There was no evidence of H. pylori infection of gallbladder on histopathological examination using H&;E, Giemsa and Warthin Starry stains. H. pylori DNA were detected in 16 patients (32.6%) and none of the 12 controls by PCR analysis (p?=?0.025). The presence of H. pylori DNA in bile and/or gallbladder was associated with positive urea breath test, (p?H. pylori infection of bile and gallbladder.

Conclusions

Nearly three quarters of patients with positive urea breath test have detectable H. pylori DNA in gallbladder tissue. The significance of these findings needs to be further evaluated.  相似文献   
118.
This study examines the patterns of hand preference and unintentional injuries of attempted hand switchers and hand non-switchers. Data were collected from 3698 participants in Kharagpur, India, on measures of hand preference, hand switching, and unintentional injuries. The direction of left- or right-handedness was on the basis of hand used for the item “writing on paper” and the degree of handedness was based on the average score of remaining items in the handedness inventory. Results reveal that, among attempted hand-switchers, learned right-handers were not right-sided in hand continuum as the natural right-handers, but left-handers were left-sided as natural left-handers. With increasing age the learned right-handers become less right-sided and natural right-handers become more right-sided. Females (males) are found to be more right-handed than males (females) among learned right-handers (natural right-handers). On the direction of handedness, the learned right-handers have more than twice the risk of unintentional injuries than the natural right- and left-handers. On degree of handedness, the use of inconsistent left and both hands among natural left-handers, the use of inconsistent right and both hands among natural right-handers, and the use of weak right hand among learned right-handers increase their vulnerability to unintentional injuries. Any deviation from the genetic make-up in hand use elevates the risk of unintentional injuries, suggesting that one should not change the biological hand.  相似文献   
119.
Recent advances in the understanding of Alzheimer’s disease pathogenesis have led to the development of numerous compounds that might ameliorate the disease process. Research in the field of Alzheimer’s disease therapy has been partly successful in terms of developing symptomatic treatments, but also had several failures in terms of developing disease-modifying therapies. These successes and failures have led to a debate about the potential deficiencies in our understanding of the pathogenesis of Alzheimer’s disease and potential pitfalls in diagnosis, choice of therapeutic targets, development of drug candidates, and design of clinical trials. Many clinical and experimental studies are ongoing, but we need to acknowledge that a single cure for Alzheimer’s disease is unlikely to be found and that the approach to drug development for this disorder needs to be reconsidered. Preclinical research is constantly providing us with new information on pieces of the complex Alzheimer’s disease puzzle, and an analysis of this information might reveal patterns of pharmacological interactions instead of single potential drug targets. Several promising randomized controlled trials are ongoing, and the increased collaboration between pharmaceutical companies, basic researchers, and clinical researchers has the potential to bring us closer to developing an optimum pharmaceutical approach for the treatment of Alzheimer’s disease.  相似文献   
120.
The objective of this study is to evaluate clinical picture, radiological findings and response to treatment in patients with antibiotic associated status epilepticus (SE). In a retrospective review, 12 out of 117 (10%) patients with SE had temporal association with antibiotic administration. Their medical history, clinical findings, and duration and type of SE were recorded. Serum chemistry, blood counts, cranial MRI, EEG and CSF examination were carried out. The offending antibiotics were withdrawn and the patients were treated with phenytoin, lorazepam, sodium valproate or midazolam. The response to treatment was recorded and death during hospital stay noted. The median age of the patients was 36 (18 and 74) years and 5 were females. Eight patients had convulsive and four nonconvulsive SE. The median duration of status was 12 h. The antibiotics related to SE included intravenous cephalosporin (ceftazidime 5, amoxyclavulenic acid 2, piperacillin 2, cefepime 1) and quinolones (levofloxacin 3, ofloxacin 1, ciprofloxacin 2) in isolation or in combinations. Five patients had hepatic (41.7%) and 6 (50%) renal failure; the later received higher than the recommended dose of antibiotics. Cranial MRI was abnormal in 7 out of 9 (77.8%) patients that include cortical lesion in one, corticosubcortical in three and subcortical in three. SE responded to first antiepileptic drug in four and to second in five patients. Three patients (25%) had refractory SE. Eight (66.7%) patients died and death was related to SE in 2 patients. 10% SE patients may be related to antibiotics. Hence the antibiotic should be carefully chosen in patients with hepatic and renal failure, and the dose should be modified.  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