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   5125篇
  免费   400篇
  国内免费   21篇
耳鼻咽喉   28篇
儿科学   99篇
妇产科学   134篇
基础医学   599篇
口腔科学   92篇
临床医学   566篇
内科学   1116篇
皮肤病学   55篇
神经病学   358篇
特种医学   174篇
外国民族医学   1篇
外科学   1081篇
综合类   88篇
一般理论   3篇
预防医学   303篇
眼科学   161篇
药学   295篇
中国医学   14篇
肿瘤学   379篇
  2023年   46篇
  2022年   109篇
  2021年   201篇
  2020年   101篇
  2019年   166篇
  2018年   176篇
  2017年   154篇
  2016年   149篇
  2015年   167篇
  2014年   234篇
  2013年   262篇
  2012年   440篇
  2011年   424篇
  2010年   217篇
  2009年   181篇
  2008年   280篇
  2007年   265篇
  2006年   283篇
  2005年   272篇
  2004年   225篇
  2003年   232篇
  2002年   196篇
  2001年   72篇
  2000年   66篇
  1999年   57篇
  1998年   37篇
  1997年   26篇
  1996年   23篇
  1995年   21篇
  1994年   15篇
  1993年   13篇
  1992年   38篇
  1991年   29篇
  1990年   27篇
  1989年   28篇
  1988年   21篇
  1987年   17篇
  1986年   15篇
  1985年   14篇
  1984年   19篇
  1983年   15篇
  1982年   14篇
  1980年   11篇
  1979年   14篇
  1978年   11篇
  1977年   13篇
  1976年   15篇
  1973年   13篇
  1972年   25篇
  1971年   21篇
排序方式: 共有5546条查询结果,搜索用时 15 毫秒
91.

Background:

The trematodes of the genus Fasciola (the liver flukes) are among the well-known instances of food-borne parasites worldwide. Differentiation of Fasciola species is important because of their different transmission and epidemiological characteristics. The current study was undertaken to discriminate Fasciola species in the domestic ruminants of Urmia city, Iran.

Methods:

Adult flukes were isolated from the naturally infected livers of the slaughtered water buffaloes and sheep. The flukes were initially identified based on morphological and morphometric parameters. A 618-bp-long fragment of the 28SrRNA gene of Fasciola was amplified by polymerase chain reaction (PCR). The amplified fragment was digested by DraII or AvaII enzymes for a restriction fragment length polymorphism (RFLP) analysis and sequenced for the phylogenetic tree construction.

Results:

Based on the morphometric examination, the flukes belonged to F. hepatica, F. gigantica and an intermediate Fasciola form. The PCR-RFLP analysis was able to differentiate F. hepatica from F. gigantica. While the phylogenetic reconstruction justified, to some extent, the morphological diagnosis, it failed to segregate F. hepatica from F. gigantica identified in this and the previous studies.

Conclusion:

To resolve fully the problem of taxonomy and evolution in Fasciola species, employing a broad range of molecular and morphological approaches is necessary. This is crucial for epidemiological surveys and successful clinical management of their infection.  相似文献   
92.
Introduction: Aside from examination for Clostridium difficile, the yield of stool testing in hospital-onset diarrhea is poor. Clinical practice guidelines discourage overzealous stool testing in patients with diarrhea that develops after the third hospital day. However, the adoption of this recommendation into clinical practice is limited. Furthermore, the effect of microbiology laboratory improvements on hospital-onset diarrhea testing is largely unknown. Methods: A retrospective cohort study was conducted in a university-affiliated community-hospital and included all adult inpatients who developed diarrhea after hospitalization. Results: 132 adult patients (53% female) developed diarrhea after hospitalization in 2013. The cohort’s mean age was 55.6 years. 46.2% of patients developed diarrhea in the first 3 days of hospitalization. Testing for parasites was negative in all examined 67 samples. Testing for C. difficile was positive in 13 cases (10.8%) out of 120 tested samples. Testing for other pathogens was positive in 1 sample (Campylobacter) out of 129 samples. Stool samples tested in the first 3 days of hospitalization were more likely to be positive (64.3 vs 35.7%, p = 0.1). Change in management was reported in 9 out of 14 patients (64.3%) with positive stool testing compared with 31 out of 118 patients (26.3%) with negative stool testing, p = 0.01. Conclusion: Despite improvements in stool samples’ testing, the yield continues to be low, especially in hospital-onset diarrhea past the third hospital day. Physicians’ embracement of the ‘3-day rule’ continues to be poor.  相似文献   
93.
94.
95.
We report the case of ventricular tachycardia (VT) ablation procedure in a patient with history of surgically repaired double-outlet left ventricle. The electrophysiology procedure revealed a re-entry pattern between the right-ventricle to main-pulmonary-artery conduit and the tricuspid annulus. The re-entrant mechanism was most likely promoted by a fibrous remodeling of this area, related to the surgical repair. This case is the first to describe a re-entry mechanism between fixed anatomical barriers in a repaired right ventricle of a double-outlet left ventricle. A pace mapping technique was used to highlight the VT isthmus.  相似文献   
96.
97.
PURPOSE: The present prospective, randomized clinical trial compares the outcome of surgical hemorrhoidectomy according to Parks and Milligan-Morgan in terms of hospital stay, duration of incapacity to work, symptom relief, length of morbidity, and patient convenience. METHODS: Thirty-four consecutive patients with third or fourth degree internal hemorrhoids were randomly allocated to the two groups. Before surgery, all patients were interviewed using a standard questionnaire, followed by rectal examination. All patients underwent a follow-up interview and examinations 1, 2, 4, 8, and 12 weeks after the operation. RESULTS: No serious postoperative complications were seen. Length of hospital stay (3.2 days for Parks hemorrhoidectomyvs. 4.6 days for Milligan-Morgan hemorrhoidectomy; 95 percent confidence interval, 0.2 and 2.6, respectively;P=0.02) and mean duration of incapacity to work (12.3 days for Parks hemorrhoidectomyvs. 20.2 days for Milligan-Morgan hemorrhoidectomy; 95 percent confidence interval, 5.7 and 10.2, respectively;P<0.001) differed significantly between the Milligan-Morgan and Parks patients. Until two weeks after the operation, Milligan-Morgan hemorrhoidectomy patients experienced significantly more pain. CONCLUSIONS: Our study confirms that both operations are safe, easy to perform, and lead to satisfactory results. However, the Parks procedure is the preferred option, because it minimizes patients' postoperative discomfort, is more economic, has a significantly reduced hospital stay, and has a shorter time for return to work.  相似文献   
98.
PURPOSE: Thalidomide is effective for the treatment of severe cutaneous lupus. Our aim was to study the safety and efficacy of different doses of thalidomide in this condition. METHODS: We studied patients with severe cutaneous lupus that was unresponsive to antimalarials, prednisolone, methotrexate, azathioprine, and cyclosporin A. Starting doses of 100 mg daily (n = 16 patients), 50 mg daily (n = 17), or 50 mg on alternate days (n = 15) were compared. The response to thalidomide was categorized as complete remission, partial remission, or no visible improvement. All patients received a baseline electromyogram (EMG) followed by repeat EMG every 3 to 6 months, or sooner if neuropathic symptoms developed. RESULTS: Forty-eight patients (46 female; mean [+/- SD] age, 44 +/- 12 years; range, 22 to 71 years) with discoid lupus (n = 18), subacute cutaneous lupus (n = 6), or systemic lupus erythematosus with skin involvement (n = 24) were included. The response rate was 81%, including 29 patients (60%) in complete remission and 10 (21%) in partial remission. Nine patients (19%) failed to respond. Thirteen patients (27%) developed peripheral neuropathy, which was EMG-proven in 11, including 4 patients in the 50-mg alternate-day group. Other side effects included drowsiness, constipation or abdominal pain, and amenorrhea. The relapse rate after stopping thalidomide was 67% (26/39). There was no association between a positive response to the drug and either starting doses or cumulative dose. Similarly, no association was found between peripheral neuropathy and the starting or cumulative dose. CONCLUSION: Thalidomide is effective for the treatment of severe cutaneous lupus. There were no clear dose-dependent effects. However, the high incidence of neurotoxicity, even at low doses, suggests that it may be most useful as a remission-inducing drug.  相似文献   
99.
OBJECTIVE: Continuous positive airway pressure (CPAP) by face mask is an effective method of treating severe cardiogenic pulmonary edema (CPE). However, to our knowledge, no study has provided a precise evaluation of the effects of CPAP on cardiac function in patients presenting with CPE and preserved left ventricular (LV) function. DESIGN: Prospective observational clinical study. SETTING: A 14-bed, medical ICU at a university hospital. PATIENTS: Nine consecutive patients presenting with hypoxemic acute CPE. INTERVENTIONS: All patients were selected for 30 min of CPAP with 10 cm H(2)O by mask with fraction of inspired oxygen adjusted for a cutaneous saturation > 90%. Doppler echocardiography was performed before CPAP application and during the last 10 min of breathing with CPAP. Two-tailed, paired t-tests were used to compare data recorded at baseline (oxygen alone) and after CPAP. MEASUREMENTS AND RESULTS: Four patients presented CPE with preserved left ventricular (LV) function (a preserved LV ejection fraction [LVEF] > 45%, and/or aortic velocity time integral > 17 cm in the absence of aortic stenosis or hypertrophic cardiomyopathy). Oxygenation and ventilatory parameters were improved by CPAP in all patients. Hemodynamic monitoring and Doppler echocardiographic analysis demonstrated that in patients with preserved LV systolic function, mean arterial pressure and LV end-diastolic volume were decreased significantly by CPAP (p < 0.04). In patients with LV systolic dysfunction, CPAP improved LVEF (p < 0.05) and decreased LV end-diastolic volume (p = 0.001) significantly. CONCLUSION: CPAP improves oxygenation and ventilatory parameters in all kinds of CPE. In patients with preserved LV contractility, the hemodynamic benefit of CPAP results from a decrease in LV end-diastolic volume (preload).  相似文献   
100.
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