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   927篇
  免费   57篇
  国内免费   3篇
耳鼻咽喉   13篇
儿科学   46篇
妇产科学   59篇
基础医学   82篇
口腔科学   113篇
临床医学   82篇
内科学   184篇
皮肤病学   17篇
神经病学   113篇
特种医学   29篇
外科学   109篇
综合类   5篇
预防医学   36篇
眼科学   34篇
药学   38篇
中国医学   1篇
肿瘤学   26篇
  2024年   1篇
  2023年   15篇
  2022年   26篇
  2021年   61篇
  2020年   39篇
  2019年   42篇
  2018年   52篇
  2017年   44篇
  2016年   52篇
  2015年   49篇
  2014年   65篇
  2013年   68篇
  2012年   108篇
  2011年   75篇
  2010年   26篇
  2009年   35篇
  2008年   49篇
  2007年   38篇
  2006年   54篇
  2005年   35篇
  2004年   24篇
  2003年   13篇
  2002年   11篇
  2001年   2篇
  2000年   2篇
  1999年   1篇
排序方式: 共有987条查询结果,搜索用时 0 毫秒
1.
The aim of the study was to investigate the efficiency of ram seminal plasma and fetal calf serum on freezing of buck semen. Twenty ejaculates were collected using an electro-ejaculator and split into six groups. While FCS additive was not used in A1, A2 and A3 groups, 10% FCS was added to B1, B2 and B3 groups. These groups were then edited according to whether the buck or ram SP was involved. The design of the groups was done as follows: Group A1 (control 1), group A2 without buck SP, group A3 containing ram SP instead of buck SP. Groups B1 (control 2), B2 and B3 were the FCS added forms of these groups. Progressive sperm motility percentages in Group A1 and Group B2 were found to be higher when compared to the lowest Group B3. There were no significant differences between the groups in neither the levels of reactive oxygen species nor the enzyme and glutathione activities. In conclusion, the lack of statistical difference between the groups suggested that despite the supplements used but only when the buck spermatozoa structure was healthy, the cell could preserve acrosome, DNA and the integrity of membrane.  相似文献   
2.
ObjectivesTo determine and compare surface characteristics and presence of corrosion in new and used brackets with optical light microscopy (OLM) and scanning electron microscopy (SEM), and with elemental chemical analysis with energy-dispersive X-ray spectroscopy (EDS).Materials and MethodsOLM and SEM were used to analyze 24 new and 24 used conventional premolar brackets. EDS analysis was performed in six used brackets and four new brackets with corrosion-suspected spots.ResultsOLM and SEM images showed wear/abfraction signs, striations, pits/crevices, and adherent material. Used brackets showed more deterioration than new brackets. SEM images disclosed more morphological features than OLM images. EDS analysis revealed a significantly higher phosphorus (P = .001) and sodium (P < .005) weight fraction and significantly lower amounts of chromium (P < .001) in used brackets. The iron, chromium, and nickel weight fractions did not differ significantly between the clean and corrosion-suspected spots. Of the corrosion-suspected spots analyzed by combined SEM and EDS, 44.14% and 6.90% remained corrosion-suspected on used and new brackets, respectively.ConclusionsUsed brackets showed more signs of corrosion than new ones. Combined assessment of SEM and EDS indicates that the bracket surface is affected during orthodontic treatment as a result of corrosion.  相似文献   
3.
4.
5.

Purpose

The aim of our study is to research the role and efficacy of cerebral oximetry in predicting neurologic prognosis when applied during TTM to patients experiencing coma after CA.

Methods

This study was performed on surviving adult comatose patients after CA treated with TTM. The average scores of rSO2 was measured at 6 h intervals for the first 2 days and once a day for the following 3 days with a NIRS device during TTM. The CPC scale was used to define the neurologic outcomes of patients. We compared the correlations of rSO2 values between good (CPC 1–2) and poor (CPC 3–5) neurologic outcomes in CA patients.

Results

There was no statistically significant difference identified between the prognosis groups in terms of rSO2, CPR durations, hemoglobin values and admission body temperature (p > 0.05). When the variation in rSO2 values over time is investigated, though there was no significant difference between the good and poor prognosis groups, it appeared to fall in the first 6 h in both prognosis groups. The median NT-proBNP and lactate values were observed to be higher in the poor prognosis group.

Conclusion

There is no significant correlation between rSO2 values and neurologic outcomes. Multimodal monitoring methods may be useful and further studies with a larger patient population are necessary in this area.  相似文献   
6.
BackgroundMultiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. We aimed to discuss possible predisposing factors to atherosclerosis such as carotid intima-media thickness (CIMT) and high-sensitivity C-reactive protein (Hs-CRP) levels in MS.MethodsThirty-five ambulatory patients with relapsing-remitting MS (RRMS) (22 females and 13 males) and 34 healthy controls (21 females and 13 males) with similar demographic variables were included. Blood cell counts, cholesterol levels, vitamin D and B12, Hs-CRP levels, body mass index (BMI), history of smoking, and CIMT of both groups, Expanded Disability Status Scale (EDSS) scores, and disease duration of patients were recorded. Patients with a history of other vascular diseases such as hypertension, diabetes mellitus, peripheral artery disease, and acute relapses were excluded.ResultsSixty-nine participants were included. The mean age of the study population was 35.8 ± 7.1 years. Right CIMT was significantly greater in the patient population (P < 0.001). Spearman's correlation coefficient between age and right CIMT was r = 0.41, P = 0.01. When we compared the Hs-CRP with a cut-off value of ≤ 3, the right, left, and mean CIMT levels were not statistically significant (P = 0.17; P = 0.22; P = 0.15). The mean serum vitamin D levels were higher in the patient group and this was statistically significant (P < 0.001). The statistically significant factors identified with univariate analysis with P < 0.2 were further entered into multivariate modelling.ConclusionCIMT seems to be affected in patients with MS by means of the disease itself and age. Thus, CIMT might reflect the predisposition to subclinical atherosclerosis more than Hs-CRP. Further investigation in a large MS population is still needed.  相似文献   
7.
The general impression about gallbladder carcinomas is that they are uniformly fatal; however, for the early forms, an entirely different picture indicating a very good prognosis is evolving from the high-incidence regions. We subjected 190 early gallbladder carcinomas (EGBC), defined as carcinomas confined to and above the tunica muscularis (AJCC's Tis, T1a, and T1b), and identified in cholecystectomy specimens sampled entirely according to an established protocol, to detailed analysis. Average patient age was 57.9 years (29–95). In more than half of the cases (114/190; 60 %), the tumor was inapparent by gross examination. In 81 cases (42.6 %), carcinomatous epithelium abutted the muscularis, whereas 57.4 % (n?=?109) were qualified as intramucosal with no overt contiguity with muscularis. Intraepithelial extension into Rokitansky–Aschoff sinuses (RAS) was found in 34 cases (17.8 %). At the time of data analysis, 171 patients (99 %) were alive. Overall actuarial survival was 92.3 % at 5 years and 90.4 % at 10 years. The 5- and 10-year actuarial survival rates of the intramucosal group (93.2 and 92.1 %, respectively) were not statistically different from that of the muscle-abutting group (89.7 % and 88.2 % ; p?=?0.334). Patients with RAS involvement had a significantly shorter survival than those without (p?<?0.001). Of the 33 patients with RAS involvement, 13 (39 %) died of disease, whereas only 6 of the 154 patients (4 %) without RAS involvement died of disease. Disease-related mortality in these cases occurred relatively late (median 48 months). EGBC has a very good prognosis with a 90 % 10-year survival rate. It is seen on average in patients almost a decade younger than those with advanced cancers. RAS involvement is an independent prognostic factor, and additional surgery may have to be considered for such cases. Occasional recurrences are encountered several years later, which suggests a field-effect phenomenon and warrants long-term follow-up.  相似文献   
8.
9.
10.
EGb 761 is widely used in the management of mild cognitive impairment in the elderly population. Elucidation of the effects of EGb 761 on primary haemostasis via PFA-100 could represent an important step for better understanding of the haemostatic safety of EGb 761. The purpose of this prospective study is to assess the effects of Ginkgo biloba special extract, EGb 761, on PFA-100 in vitro bleeding time in elderly patients with mild cognitive impairment. A total of 40 elderly patients aged 65-79 years who were referred for geriatric assessment and who were diagnosed as having mild cognitive impairment were included. Patients were started on 80 mg EGb-761 three times daily. The complete set of PFA-100 in vitro bleeding time and coagulation parameters including prothrombin time, activated partial thromboplastin time and International Normalized Ratio were assessed before and on the seventh day of treatment with EGb 761. There was no statistically significant prolongation in PFA-100 in vitro bleeding time or coagulation parameters in patients receiving EGb 761 after 7 days. The data about the safety of EGb 761 from the point of primary haemostasis in our elderly patient population with mild cognitive impairment casts hope for the future management of this 'difficult-to-treat' population with the promising Ginkgo extracts.  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