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   2038篇
  免费   83篇
  国内免费   11篇
耳鼻咽喉   95篇
儿科学   120篇
妇产科学   57篇
基础医学   188篇
口腔科学   59篇
临床医学   176篇
内科学   360篇
皮肤病学   30篇
神经病学   143篇
特种医学   58篇
外科学   561篇
综合类   28篇
预防医学   51篇
眼科学   64篇
药学   112篇
中国医学   3篇
肿瘤学   27篇
  2023年   9篇
  2022年   20篇
  2021年   29篇
  2020年   20篇
  2019年   29篇
  2018年   50篇
  2017年   33篇
  2016年   54篇
  2015年   57篇
  2014年   59篇
  2013年   106篇
  2012年   123篇
  2011年   138篇
  2010年   94篇
  2009年   78篇
  2008年   152篇
  2007年   159篇
  2006年   152篇
  2005年   151篇
  2004年   162篇
  2003年   120篇
  2002年   119篇
  2001年   46篇
  2000年   31篇
  1999年   28篇
  1998年   15篇
  1997年   9篇
  1996年   14篇
  1995年   11篇
  1994年   8篇
  1993年   2篇
  1992年   7篇
  1991年   5篇
  1990年   6篇
  1989年   6篇
  1988年   4篇
  1987年   4篇
  1986年   3篇
  1985年   4篇
  1984年   2篇
  1983年   1篇
  1980年   1篇
  1979年   2篇
  1978年   2篇
  1976年   3篇
  1972年   1篇
  1970年   1篇
  1968年   1篇
  1967年   1篇
排序方式: 共有2132条查询结果,搜索用时 0 毫秒
41.
OBJECTIVE: To investigate the effects of long-term levothyroxine (LT4) suppressive therapy on the heart and the effects of beta-blockade on cardiac functions. DESIGN: Twelve female patients receiving LT4, selected from a group of patients with TSH levels of 0.1-0.4 microU/ml, were evaluated. The control group consisted of 11 healthy subjects and 12 patients with TSH levels <0.05 microU/ml. METHODS: Cardiac evaluation consisted of a 12-lead electrocardiogram and an echocardiographic study. Left ventricular mass index (LVMI), isovolumetric relaxation time (IVR), left ventricular end systolic (LVESD) and diastolic diameters, early (VE) and late (VA) diastolic flow velocities and fractional shortening were evaluated. Exercise capacity was assessed with a bicycle ergometer. Both work load and maximal exercise time were measured. Atenolol was given to the patient group at a dosage of 50 mg/day for 3 months and evaluations were repeated. RESULTS: On basal evaluations, LVMI (96+/-17 vs 78+/-21 g/m(2)) and IVR (101+/-9 vs 91+/-4 ms) were found to be increased in the patients taking LT4 (P<0.01). LVESD was also lower than controls (P<0.05). A decrease in VE and an increase in VA were also observed in the patients (P<0.01). IVR decreased after atenolol (92+/-10 vs 101+/-9 ms, P<0.05). LVMI decreased and VE and VA improved but did not reach statistical significance after beta-blockade. Baseline work load and maximal exercise duration were significantly lower in the patients and improvements were observed after atenolol treatment. CONCLUSIONS: These results indicated that cardiac dysfunction may occur even when TSH is suppressed to 0.1-0.4 microU/ml with LT4. beta-blockade improved the cardiac functions.  相似文献   
42.
43.
A 28-year-old woman underwent a pylorus preserving Whipple procedure for pancreatic serous cystadenoma located on the head of the pancreas. During the operation, an internal stent (7F silastic catheter, 9 cm in length) was placed within the pancreatic duct in the area of pancreaticojejunal end-to-end Dunking type anastomosis to prevent development of fistula. The stent was positioned so that one third of its length would lie into the pancreatic duct, and it was anchored to the periductal pancreatic tissue with only one rapidly absorbable chromic suture. Leakage from the anastomosis was not observed, and she was discharged without any complaint. Early postoperative abdominal CT examination revealed that the stent was retained within the normal caliber pancreatic duct (Fig. 1a). Six months after the operation, she began to complain to epigastric pain triggered by the meals. The laboratory analysis was normal, particularly liver biochemical tests and serum amylase. The internal pancreatic stent within the dilated pancreatic duct was detected by an additional CT examination (Fig. 1b). The stent was removed endoscopically at the third attempt. The pain was resolved after its removal. Control CT examination which was taken at the 18th month after removal of the stent showed dilatation of the pancreatic duct (Fig. 2a). The patient remained free of any complaint, although regressed pancreatic duct dilatation has persisted over 4 years of follow-up (Fig. 2b).  相似文献   
44.
45.
The new measures implemented in hospitals also altered the operation of orthopedics and traumatology departments. The main purpose of this article is to discuss how orthopedic oncology clinics should be organized during the pandemic and to present the process management scheme for patients requiring orthopedic surgery, including trauma surgery, from diagnosis to treatment, together with our experiences. Instead of thinking about the global emergence of the epidemic, it is time to act decisively. At first glance, the coronavirus disease 2019 (COVID-19) pandemic and orthopedics may seem to be unrelated disciplines, but the provision of healthcare services to patients who require them proves that these two fields are parts of the same whole. Our experiences in treating neutropenic, lymphocytopenic, and chemotherapy patients seem to have proven beneficial during this process. We operated on 10 biopsy patients, 15 primary bone sarcomas, 9 soft tissue sarcomas, and 82 trauma patients within this time frame. Only three patients were suspected to have COVID-19 before admission. The early identification, strict isolation, and effective treatment of these patients prevented any nosocomial infections and disease-related comorbidities. This success is the result of the multidisciplinary cooperation of the Ministry of Health, our hospital, and our clinic.  相似文献   
46.
47.
The aim of this study was to examine the traumatic mental growth and psychological resilience status of females who were receiving inpatient treatment at a district mental health hospital and had a history of being subjected to violence. One hundred-twenty female patients with a history of exposure to violence participated in the study. An introductory information form, the Traumatic Growth Inventory (TGI) and the Psychological Resilience Scale for Adults (PRSA) were used for data collection. This study found that all the participants were subjected to emotional violence, 65.8% to physical violence, 30.8% to sexual violence, and 94.2% to verbal violence at some point in their lives. Their TGI mean score (60.96?±?11.91) was above average, while their PRSA mean score (97.90?±?9.18) was below average. The participants' mean scores on the TGI and PRSA did not vary significantly by the type of violence (p?>?0.05) to which the women were exposed. Moreover, no statistically significant relationship was found between the TGI and the PRSA total scale and subscale mean scores (p?>?0.05). This study found that the posttraumatic growth of females who had a history of physical or emotional or sexual abuse was positive, and that their psychological resilience levels were inadequate.  相似文献   
48.
Anaplasma phagocytophilum is the agent of human anaplasmosis, the second most common tick-borne illness in the United States. This pathogen, which is closely related to obligate intracellular organisms in the genera Rickettsia, Ehrlichia, and Anaplasma, persists in ticks and mammalian hosts; however, the mechanisms for survival in the arthropod are not known. We now show that A. phagocytophilum induces expression of the Ixodes scapularis salp16 gene in the arthropod salivary glands during vector engorgement. RNA interference-mediated silencing of salp16 gene expression interfered with the survival of A. phagocytophilum that entered ticks fed on A. phagocytophilum-infected mice. A. phagocytophilum migrated normally from A. phagocytophilum-infected mice to the gut of engorging salp16-deficient ticks, but up to 90% of the bacteria that entered the ticks were not able to successfully infect I. scapularis salivary glands. These data demonstrate the specific requirement of a pathogen for a tick salivary protein to persist within the arthropod and provide a paradigm for understanding how Rickettsia-like pathogens are maintained within vectors.  相似文献   
49.
OBJECTIVE: Our objective was to assess the frequency and clinical characteristics of migraine in the patients with CM-1. METHODS: We analyzed migraine in 73 patients with CM-1. Migraine was classified according to the new International Headache Society criteria. We did not include patients who had intracranial, parenchymal, or cervical lesions other than CM-1 on brain and cervical magnetic resonance imaging. RESULTS: Of the 73 patients diagnosed as having CM-1, 11 (15.06%) had migraines; of them, 8 (10.95%) had chronic migraines, 2 (2.73%) had migraines with auras, and 1 (1.36%) had migraines without auras. The patients who had both migraines and CM-1 (group 1) were compared regarding clinical characteristics and demographic features to the control group having chronic migraines. The control group comprised subjects free of CM-1. Onset age of pain was earlier and the frequency of headache days per month, baseline pain intensity, exacerbation of pain intensity, nausea, vomiting, and pain aggravated by physical activity were significantly higher in group 1. CONCLUSIONS: Although we found the frequency of migraine to be similar to that in population-based studies, we detected a threefold increased frequency of chronic migraine in this special population. We believe that CM-1 may be a factor associated with chronic migraine.  相似文献   
50.

Objective

The aim of this research was to assess the relationship between mitral annular calcification (MAC) and whole blood viscosity (WBV).

Subjects and Methods

A total of 184 patients with MAC and 133 patients without MAC were enrolled in the study. The WBV was calculated with a confirmed formulation using the hematocrit and total plasma protein at a low shear rate (LSR) and high shear rate (HSR). Early diastolic mitral annular velocity (Ea) and late diastolic mitral annular velocity (Aa) were measured using pulse Doppler tissue echocardiography. Pearson''s correlation analysis was performed to assess the relationship between WBV and mitral annular motion velocities. The effects of different variables on the occurrence of MAC were assessed in univariate and multivariate logistic regression analysis.

Results

In patients with MAC, WBV values were significantly higher at HSR (18.04 ± 0.84 vs. 17.25 ± 0.96 208 s-1, p < 0.001) and at LSR (78.0 ± 14.2 vs. 61.9 ± 17.1 0.5 s-1, p < 0.001). The WBV at HSR and LSR were significantly correlated with Ea (r = −0.477, p < 0.001; r = −0.385, p < 0.001, respectively) and Aa (r = −0.544, p < 0.001; r = −0.323, p < 0.001, respectively). Multivariate analysis showed that WBV of both shear rates was an independent predictor of MAC. Using the ROC curve, a cut-off value of 70.1 for WBV at LSR had a sensitivity of 83.7% and a specificity of 73.7% (AUC 0.785, p < 0.001) and a WBV cut-off value of 17.5 at HSR had a sensitivity of 79.6% and a specificity of 71.4% (AUC 0.761, p < 0.001) for the prediction of MAC.

Conclusion

Patients with MAC had significantly higher WBV, which independently predicted the presence of MAC. WBV had an inverse correlation with mitral annular motion velocities, indicating that a higher WBV may lead to greater limitation in annular motion and, thus, more calcification.Key Words: Mitral valve calcification, Shear stress, Blood viscosity  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