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   54879篇
  免费   3695篇
  国内免费   1631篇
耳鼻咽喉   739篇
儿科学   1217篇
妇产科学   757篇
基础医学   5353篇
口腔科学   1266篇
临床医学   5567篇
内科学   8384篇
皮肤病学   2214篇
神经病学   3478篇
特种医学   1332篇
外国民族医学   3篇
外科学   2262篇
综合类   7542篇
现状与发展   6篇
一般理论   1篇
预防医学   5536篇
眼科学   1557篇
药学   8619篇
  32篇
中国医学   2749篇
肿瘤学   1591篇
  2024年   75篇
  2023年   601篇
  2022年   1341篇
  2021年   1984篇
  2020年   1680篇
  2019年   1563篇
  2018年   1562篇
  2017年   1660篇
  2016年   1709篇
  2015年   1821篇
  2014年   3319篇
  2013年   3960篇
  2012年   3401篇
  2011年   3541篇
  2010年   2832篇
  2009年   2650篇
  2008年   2750篇
  2007年   2787篇
  2006年   2342篇
  2005年   2159篇
  2004年   1829篇
  2003年   1551篇
  2002年   1261篇
  2001年   1201篇
  2000年   984篇
  1999年   951篇
  1998年   772篇
  1997年   744篇
  1996年   667篇
  1995年   638篇
  1994年   569篇
  1993年   479篇
  1992年   510篇
  1991年   449篇
  1990年   381篇
  1989年   401篇
  1988年   376篇
  1987年   335篇
  1986年   294篇
  1985年   357篇
  1984年   305篇
  1983年   225篇
  1982年   241篇
  1981年   199篇
  1980年   162篇
  1979年   128篇
  1978年   114篇
  1977年   85篇
  1976年   61篇
  1975年   58篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
941.
Abstract

Objective: The Australian Therapy Outcome Measures for Occupational Therapy (AusTOMs-OT) are used internationally to measure the outcomes of occupational therapy services across diagnoses, ages, and health care settings. This study reports on the inter-rater and test–retest reliability of the Self-care and Transfer scales as well as the intra-rater reliability of all scales of the Swedish (AusTOMs-OT-S) translation. Methods: Fifteen occupational therapists rated 11 case study clients on two occasions, separated by two weeks. Test–retest reliability and inter-rater reliability were calculated for the Self-care scale and Transfer scales. Moreover, intra-rater reliability was calculated for each of the 15 therapists across all 12 scales. Results: The inter-rater reliability intraclass correlation coefficients (ICCs) were all found to be high to very high, ranging from ICC 0.762 to 0.904; the intra-rater reliability coefficients were also very good with 11 of the 15 therapists achieving ICCs of 0.745 or over, and finally the test–retest ICCs were also found to be high, ranging from 0.705 to 0.920. Conclusions: Although further research is required to confirm reliability, preliminary reliability of the AusTOMs-OT Swedish translation has been demonstrated and therapists can have confidence when using the scales.  相似文献   
942.
目的对Diasys R/S2003和普利生尿沉渣分析系统进行性能及临床应用的评估。方法分别对两台尿沉渣仪与牛鲍氏计数板法进行可比性试验,并对两仪器作准确性、重复性、线性检测;对Diasys进行携带污染率检查。结果Diasys R/S2003和普利生均与牛鲍氏计数板法显示相关(r〉r0.01)且有非常显著性意义(P〈0.01);准确率分别为124.2%和95.8%;重复性低值CV%分别为6.5%和3.6%,高值CV%分别为6.2%和3.7%;且均显示良好线性;而Diasys的携带污染率为0.14%。结论两台仪器均符合NCCLS尿沉渣定量分析标准,检测结果与临床相符,具有准确性好、精密度高、操作简便、污染少、成本低等优点,因此两者都是目前比较理想的尿沉渣分析仪。  相似文献   
943.
The aim of this study was to determine specific pattern of port site microbial colonisation, sensitivity and resistance to different antibiotics of bacteria isolated from port site infection (PSI) in low risk patients after elective laparoscopic cholecystectomy in surgical wards at tertiary care hospital of Kashmir. This is a prospective study. The study included 675 consecutive patients of postoperative PSI after elective laparoscopic cholecystectomy for symptomatic cholelithiasis over a period of 12 months. Culture swabs were taken from port sites with signs of PSI and transported to the microbiology laboratory. The positive swab cultures were subjected to antibiotic susceptibility test. The data obtained was analysed by using appropriate statistical analytical tests. The incidence of PSI after elective laparoscopic cholecystectomy is 6·7%. The commonest organism responsible for PSI is pseudomonas, 19 (42·2%) cases. Most of the strains of organisms isolated were resistant to commonly used antibiotics in the hospital,pseudomonas was found 100% resistant to the combination of ampicillin + sulbactum and ceftriaxone and it was sensitive to imipenem, amikacin and vancomycin in 89·47,57 and 52·63% of cases respectively. Our study will be helpful in choosing effective empirical prophylactic antibiotic therapy in cases of elective laparoscopiccholecystectomy and will have a great impact on morbidity and mortality in them because of PSI.  相似文献   
944.
目的研究并分析安徽地区420例结核分枝杆菌对一线、二线抗结核药物菌耐药情况,为结核病临床治疗和结核病控制提供科学依据。方法采用绝对浓度法对420例结核分枝杆菌临床分离株进行一线、二线抗结核药物敏感试验。结果对一线抗结核药物总耐药率和耐多药率分别是29.05%和14.52%;其中初治耐药率和耐多药率分别是15.93%、6.79%,复治耐药率和耐多药率分别是52.86%、30.0%;RIF、INH、SM、EMB耐药率分别是22.14%、20.0%、17.38%和0.95%。抗二线结核药物总耐药率为22.62%,其中左氧氟沙星和丙硫乙烟胺的耐药率较高,分别为13.33%(56/420)和12.86%(54/420),年龄段41~60岁耐药率均显著高于其他年龄段(P〈0.05);男性和女性病例组间均无统计学显著性差异(P〉0.05)。结论安徽地区结核菌耐药情况仍然十分严重,应加强抗结核药物的耐药性监测,同时根据药敏试验结果选择科学有效的化疗方案。  相似文献   
945.
Ultraviolet (UV) radiation exposure has been known to cause irreparable damages to human skin. The daunting risk of UV radiation exposure faced by military personnel led to the development of a sunscreen formulation which has superior sun protection factor combined with the ability to counteract reactive oxygen species. The present work deals with the preclinical safety evaluation of the sunscreen formulation comprising of four US FDA approved UV filters; namely avobenzone, octinoxate, oxybenzone, titanium dioxide along with melatonin and pumpkin seed oil, via OECD protocols of assessing acute oral and dermal toxicity; skin sensitizing; skin irritating; ocular irritating and genotoxic potential. Both oral and dermal LD50 values were found to be ˃2000 mg/kg body weight in adult Wistar albino rats using acute dermal and oral toxicity tests. The sunscreen formulation was found to be non-sensitizing to the skin of guinea pigs and non-irritating to both skin and eyes of rabbits. The sunscreen formulation was also found to be non-mutagenic which was affirmed by a battery of genotoxicity and muagenicity assays. The results obtained from this preclinical study indicated that the sunscreen formulation is non toxic and safe in animal models. This study along with additional preclinical evaluations may serve as a basis for considering the formulation as a potential candidate for further trials to establish its efficacy, tolerability and applicability.  相似文献   
946.
Abstract

Objective

To describe the rate of occurrence of unsuspected decrease in sensitivity of the sound processor microphone and to evaluate its effect on the patient's audiological performance in terms of reduction in speech recognition scores.

Design

Speech processor microphones were tested by connecting the speech processor acoustic monitor circuit to a hearing aid analyzer. The response curves were compared with those obtained from fully working microphones.

During a 6-month investigation period, microphone response curves were measured from a group of cochlear implant recipients who had not reported any problems. Despite the absence of any subjective problem, some microphones were found to show a loss of sensitivity. Their users, aged between 4 and 67 years, were tested both with the defective and a working microphone in order to calculate the correlation between the degree of microphone failure and the decline in audiological performance.

To quantify the effect of microphone failure, patients’ speech recognition skills were measured by live voice connected discourse tracking series administered in different conditions and by recorded sentences lists.

Results

A total of 120 apparently fully functioning sound processors were tested in the investigation: 33 (27.5%) were affected by a subjectively unreported sensitivity decrease. Speech-tracking scores correlated significantly with the loss of microphone sensitivity in all test conditions (r = 0.69–0.77, P < 0.05). A high degree of correlation was also found for speech audiometry tests (r = 0.70–0.73, P < 0.05). Microphone sensitivity loss affected speech recognition skills, especially without lip reading and in the presence of background noise.

Conclusion

The results indicate that any reduction in sound processor microphone sensitivity causes a degree of hearing decline that negatively affects the cochlear recipient's clinical performance. Microphone faults are often unreported events, and their occurrence rate is underestimated. To establish that the microphone is providing correct input to the speech processor a standard control procedure, including technical and clinical checks, is needed in clinical practice.  相似文献   
947.
The authors studied the remote masking (RM) in patients with Menière's disorder during the hearing loss fluctuations produced either by the disorder or by the glycerol test (Klockhoff). The RM was recorded for pulsed tones of 250, 500 and 1 000 Hz; the masker was a continuous narrow-band noise centered at 3 000 Hz, with 305 Hz (2 875–3 180 Hz) bandwidth, delivered at an overall level of 98 dB SPL. The results showed that the RM decreases during the acute phase, i.e. when the hearing loss increases, and, increases if the glycerol tests do not significantly modify the RM value. They seem to confirm the hypothesis that the RM may be due to a mechanical effect in the internal ear and suggest the possibility of using the RM as a test of end-organ rigidity.

Résumé

Les auteurs ont étudié le RM sur des sujets atteints de maladie de Menière pendant les fluctuations du déficit auditif produites par les crises ou provoquées par le test au glycérol selon Klockhoff. Le RM a été enregistré pour des tons de 250, 500 et 1 000 Hz interrompus deux fois par seconde et d'une durée de 250 ms; le son masquant était un bruit à bande étroite centrée sur la fréquence de 3 000 Hz, d'une largeur de 305 Hz (2 875–3 180 Hz), envoyé en continu à. 98 dB SPL. Les résultats ont montré que la valeur en décibels du RM diminue pendant les crises, lorsque le deficit auditif augmente; au contraire, le RM augmente au moment oú le glycérol produit une amélioration des seuils d'audition. Pour des tests au glycérol négatifs, nous n'avons observé aucune variation marquée du RM. Ces résultats vérifient l'hypothèse de l'origine mécanique du RM et suggèrent la possibilité d'utiliser le RM pour tester la rigidité de la membrane basilaire.  相似文献   
948.
Objectives. To characterize glucose tolerance and adipokine serum levels in a cohort of women shortly after delivery. Study Design. A study population of healthy pregnant women (n = 65) was invited to undergo a standardized oral glucose tolerance test within 24 h after delivery at the University Hospital of Leipzig. As controls, 30 nonpregnant healthy, lean women were studied. Glucose, insulin, proinsulin, c-peptide, leptin, adiponectin, and soluble leptin receptor levels were compared in cases and controls by using the Mann–Whitney U two-sample statistics and correlation according to Spearman. Results. As compared to normal glucose tolerant (NGT) women postpartum, fasting c-peptide levels were significantly higher (NGT mothers = 0.23 nmol/L, controls: 0.49 nmol/L, p < 0.001), whereas proinsulin serum levels were significantly lower in nonpregnant controls (NGT mothers = 1.37 pmol/L, controls = 1.00 pmol/L, p = 0.05). Considering fasting adiponectin values, postpartum adiponectin was significantly decreased compared with controls (NGT mothers = 6.9 μg/L, controls = 8.9 μg/L, p = 0.05). Fasting serum levels of leptin (NGT mothers = 17 ng/mL, controls = 10.6 ng/mL, p < 0.009) and soluble leptin receptor (NGT mothers = 34.4 ng/mL, controls = 17.7 ng/mL, p < 0.001) were increased postpartum. Conclusion. We found significantly lower adiponectin and higher leptin sera levels in women postpartum as compared to nonpregnant women. In addition, adipokine serum levels shortly after delivery were related to parameters of adiposity and glucose tolerance. We hypothesize that women in the post-delivery period exhibit biochemical features resembling metabolic syndrome, impaired glucose tolerance, and derangement of the adipokine system.  相似文献   
949.
Testing for embryotoxicity in vitro is an attractive alternative to animal experimentation. The embryonic stem cell test (EST) is such a method, and it has been formally validated by the European Centre for the Validation of Alternative Methods. A number of recent studies have underscored the potential of this method. However, the EST performed well below the 78% accuracy expected from the validation study using a new set of chemicals and pharmaceutical compounds, and also of toxicity criteria, tested to enlarge the database of the validated EST as part of the Work Package III of the ReProTect Project funded within the 6th Framework Programme of the European Union. To assess the performance and applicability domain of the EST we present a detailed review of the substances and their effects in the EST being nitrofen, ochratoxin A, D-penicillamine, methylazoxymethanol, lovastatin, papaverine, warfarin, β-aminopropionitrile, dinoseb, furosemide, doxylamine, pravastatin, and metoclopramide. By delineation of the molecular mechanisms of the substances we identify six categories of reasons for misclassifications. Some of these limitations might also affect other in vitro methods assessing embryotoxicity. Substances that fall into these categories need to be included in future validation sets and in validation guidelines for embryotoxicity testing. Most importantly, we suggest conceivable improvements and additions to the EST which will resolve most of the limitations.  相似文献   
950.
Many functional diseases are related to dysautonomia, and heart rate variability has been used to assess dysautonomia. However, heart rate variability has not been studied in Spleen-Qi deficiency syndrome (SQDS). Healthy volunteers (n = 37) and patients with SQDS (n = 67), recruited from the Clinic of the State University of Ecatepec Valley were included in the study. Outcome measures were average heart rate, standard deviation of the normal-to-normal heartbeat intervals, low frequency (LF), high frequency (HF) power, and the LF/HF ratio. Also, intestinal peristalsis, gastrointestinal symptoms (GSs), fatigue, and level of attention were measured. Standard deviation of the normal-to-normal heartbeat intervals (17 ± 2.3%) and HF (14 ± 3.1%) were lower in SQDS patients (17 ± 1.3%) than in healthy volunteers. SQDS patients had higher heart rate, LF power, LF/HF ratio, and fatigue scores (9.6 ± 1.12%, 16 ± 2.1%, 22 ± 3.8%, and 21 ± 4.1%). The fatigue correlated positively with the LF/HF ratio and negatively with HF power. The SQDS group had lower concentration performance (16.2 ± 1.9%) in the d2 test. The intestinal peristalsis showed a reduction (15 ± 1.3%) as compared with control. GS score and peristalsis correlated negatively with HF. Our results suggest that the pathology of SDQS could be associated with a low vagal tone which causes a decrease in peristalsis, increased fatigue, reduced attention, and appearance of GSs.  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