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   12036篇
  免费   559篇
  国内免费   86篇
耳鼻咽喉   263篇
儿科学   519篇
妇产科学   390篇
基础医学   1102篇
口腔科学   450篇
临床医学   997篇
内科学   2797篇
皮肤病学   225篇
神经病学   706篇
特种医学   652篇
外国民族医学   1篇
外科学   2317篇
综合类   292篇
一般理论   3篇
预防医学   506篇
眼科学   250篇
药学   662篇
中国医学   37篇
肿瘤学   512篇
  2023年   108篇
  2022年   230篇
  2021年   392篇
  2020年   206篇
  2019年   281篇
  2018年   331篇
  2017年   249篇
  2016年   379篇
  2015年   448篇
  2014年   541篇
  2013年   637篇
  2012年   794篇
  2011年   802篇
  2010年   497篇
  2009年   454篇
  2008年   791篇
  2007年   885篇
  2006年   864篇
  2005年   792篇
  2004年   693篇
  2003年   553篇
  2002年   484篇
  2001年   92篇
  2000年   85篇
  1999年   84篇
  1998年   114篇
  1997年   103篇
  1996年   107篇
  1995年   71篇
  1994年   61篇
  1993年   59篇
  1992年   30篇
  1991年   31篇
  1990年   40篇
  1989年   45篇
  1988年   42篇
  1987年   42篇
  1986年   39篇
  1985年   27篇
  1984年   12篇
  1983年   19篇
  1982年   24篇
  1981年   8篇
  1980年   15篇
  1979年   11篇
  1978年   12篇
  1977年   10篇
  1976年   11篇
  1973年   10篇
  1971年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
BACKGROUND AND OBJECTIVE: To evaluate patient-reported pain induced by phacoemulsification performed by residents using topical anesthesia. PATIENTS AND METHODS: This prospective study comprised 81 eyes of 76 consecutive patients having phacoemulsification under topical anesthesia. Surgery was performed by an experienced surgeon (group 1; n=41 eyes) or by two residents (group 2; n=40 eyes). No sedation or intracameral anesthesia was used in either group. Eighty eyes had clear corneal phacoemulsification with foldable acrylic posterior chamber intraocular lens implantation. Patients were asked postoperatively to grade the pain they experienced during the procedure using a visual analog pain scale from 0 to 10. RESULTS: The median pain score for the overall pain was 1.59 +/- 1.43 (range: 0 to 6) in group 1 and 1.95 +/- 1.64 (range: 0 to 7) in group 2 (P = .291). The mean pain score for the maximum pain perceived was 2.39 +/- 1.86 (range: 0 to 7) in group 1 and 2.53 +/- 1.67 (range: 0 to 7) in group 2 (P = .734). There was no significant correlation between the duration of surgery and the overall pain score (r = 0.102, P = .365). CONCLUSION: Topical anesthesia had sufficient analgesic effects in selected patients undergoing phacoemulsification cataract surgery by resident surgeons. The pain felt during the operation was low and tolerable.  相似文献   
102.
Purpose : To evaluate the additive ocular hypotensive effect of latanoprost and dorzolamide in combination, on intraocular pressure reduction in patients with elevated intraocular pressure (IOP). Methods : Thirty patients with ocular hypertension or early capsular or primary open-angle glaucoma and elevated IOP were randomly assigned to two parallel treatment groups. The treatment period was twenty days. Fifteen patients (Group 1) received latanoprost once daily during the first ten days and, in addition, dorzolamide three times daily during the second ten days. Fifteen patients (Group 2) received dorzolamide three times daily during the first ten days and, in addition latanoprost, once daily during the second ten days. IOP was measured and conjunctival hyperemia was evaluated. Results : In Group 1, the mean IOP on day 0 was 26.8 mmHg; on day 10, 18.7 mmHg; and on day 20, 15.9 mmHg. In Group 2, the mean IOP on day 0 was 26.3 mmHg; on day 10, 21.2 mmHg; and on day 20, 16.1 mmHg. Both groups had clinically significant IOP- lowering effect on day 10 as compared with baseline day (30.2% and 19.4% respectively) (p < 0.01). When dorzolamide was added to latanoprost, the additional IOP reduction was 2.8 mmHg (15%) (p<0.01) compared with 5.1 mmHg (24.1%) (p<0.01when latanoprost was added to dorzolamide. No local serious adverse reactions were observed. A mild but statistically significant increase in conjunctival hyperemia was seen in latanoprost applied patients. Conclusions : The results showed that latanoprost and dorzolamide can be combined successfully to reduce IOP with their additive effects.  相似文献   
103.
杨解人  李庆平  饶曼人 《药学学报》1992,27(10):729-733
大鼠ip前胡丙素(Pra-C 15 mg/kg,bid×3d)和硝苯啶(Nif 60μg/kg,bid×3d),使离体缺血再灌注工作心脏的收缩(AP,LVSP,+dP/dtmax)舒张(-dP/dtmax LVEDP和T值)性能在35min时得到改善,尤以舒张性能改善明显,并能促进CO,CF,SV及HR恢复,改善心脏工作效率,减少CK释放和心肌线粒体钙含量,表明Pra-C和Nif对心肌缺血都有保护作用,Pra-C的效应与Nif相近。  相似文献   
104.
Background:Hepatoblastoma is rare cancer that responds well to risk-based chemotherapy, and surgical treatment is needed to achieve complete remission and satisfactory survival rates in hepatoblastoma patients. In this study, we evaluated the clinical features and treatment outcomes of pediatric hepatoblastoma patients treated in our clinic.Methods:Eighteen patients with hepatoblastoma who were treated and followed up in our center between June 1999 and June 2020 were analyzed retrospectively. All patients were evaluated by a multidisciplinary team and managed using a risk-based protocol (SIOPEL-1 and SIOPEL-3).Results:The patients’ mean age at diagnosis was 38.33 ± 52.34 months. Sixteen patients (89%) received neoadjuvant chemotherapy, and 2 patients (11%) who underwent complete mass excision at diagnosis received adjuvant chemotherapy. After neoadjuvant therapy, the tumor was completely resected in 8 patients (45%), while liver transplantation was performed in 6 patients (34%) because complete resection of the tumor was not possible. Two patients died before surgical treatment. One patient relapsed with lung metastasis after salvage chemotherapy. She is alive without disease at 64 months. The mean follow-up time was 59.3 ± 49.8 months; 5-year overall and disease-free survival rates were 88.9% and 80.8%, respectively. The 5-year overall survival rate was 100% for both liver transplant and resected patients, whereas 5-year disease-free survival was lower in transplant patients (75% vs 100%, P < .001).Conclusion:Multidisciplinary follow-up is especially important for patients who may need liver transplantation. Some patients may benefit from new treatment options such as radiofrequency ablation and cyberknife treatment.  相似文献   
105.
Background:The aim of the study was to evaluate whether a new and successful treatment opportunity can be provided in acute pancreatitis and may prevent symptomatic treatments and show its effect through etiopathogenesis. Therefore, we want to investigate the efficacy of golimumab in an experimental rat model of cerulein-induced acute pancreatitis.Methods:A total of 35 rats, including 7 rats in each group, were distributed into 5 groups (sham, acute pancreatitis, placebo, acute pancreatitis + golimumab 5 mg/kg, and acute pancreatitis + golimumab 10 mg/kg). An experimental cerulein-induced acute pancreatitis model was accomplished by intraperitoneal cerulein injections. After sacrification, rat blood samples were collected for amylase, IL-6, and IL-1beta measurements. Histopathological analysis of the pancreas was performed with Tunel and hematoxylin & eosin staining.Results:Amylase, IL-6, and IL-1beta levels were found to be increased in the acute pancreatitis group. IL-1beta, amylase, IL-6 levels, and pancreatic inflammation were all significantly decreased in golimumab groups (P < .01). Moreover, in both golimumab groups, golimumab treatment significantly reduced apoptosis in pancreatic tissues (P < .05). Golimumab treatment was found to significantly reduce edema formation, inflammation, vacuolization, and fat necrosis of pancreatic tissues (P < .05).Conclusion:Firstly in the literature, we investigated the efficacy of golimumab in the experimental acute pancreatitis model. In the light of our findings, it could be suggested that golimumab may be an effective and safe therapeutic option in the treatment of patients with acute pancreatitis.  相似文献   
106.
Earth materials have been used in construction as safe, healthy and environmentally sustainable. It is often challenging to develop an optimum soil mix because of the significant variations in soil properties from one soil to another. The current study analyzed the soil properties, including the grain size distribution, Atterberg limits, compaction characteristics, etc., using multilinear regression (MLR) and artificial neural networks (ANN). Data collected from previous studies (i.e., 488 cases) for stabilized (with either cement or lime) and unstabilized soils were considered and analyzed. Missing data were estimated by correlations reported in previous studies. Then, different ANNs were designed (trained and validated) using Levenberg-Marquardt (L-M) algorithms. Using the MLR, several models were developed to estimate the compressive strength of both unstabilized and stabilized soils with a Pearson Coefficient of Correlation (R2) equal to 0.2227 and 0.766, respectively. On the other hand, developed ANNs gave a higher value for R2 than MLR (with the highest value achieved at 0.9883). Thereafter, an experimental program was carried out to validate the results achieved in this study. Finally, a sensitivity analysis was carried out using the resulting networks to assess the effect of different soil properties on the unconfined compressive strength (UCS). Moreover, suitable recommendations for earth materials mixes were presented.  相似文献   
107.
BackgroundAbdominal aortic aneurysm (AAA) has risk factors similar to those of atherosclerosis. Salusin-β and arterial stiffness are novel parameters that have been shown to predict atherosclerosis and related cardiovascular disorders. However, their predictive value for detecting AAA remains unclear.MethodsForty-eight patients with AAA and 47 age- and sex-matched participants without AAA were enrolled in the study. Arterial stiffness parameters were obtained via an oscillometric Mobil-O-Graph PWA Monitor device (IEM GmbH) with integrated ARCSolver software (Australian Institute of Technology). Plasma salusin-β levels were analyzed using an enzyme-linked immunosorbent assay reagent kit (Abbkine, Inc). The measured salusin-β levels and arterial stiffness parameters of the AAA and control groups were compared.ResultsSalusin-β levels were significantly lower in patients with AAA (P = .014). There was a significant negative correlation between salusin-β levels and abdominal aorta diameter. No significant difference was detected between AAA and control groups in terms of arterial stiffness parameters (P > .05). In backward multiple regression analysis, the presence of AAA, platelet count, and augmentation index were found to be independent predictors of salusin-β levels (P = .006 and P = .023, respectively).ConclusionArterial stiffness parameters were not found to be associated with AAA. Contrary to previous results regarding atherosclerosis and related cardiovascular disorders, salusin-β levels were found to be lower in patients with AAA. Although AAA is thought to have similar risk factors as atherosclerosis, the exact pathophysiologic mechanism remains unclear.  相似文献   
108.
With the increase in the importance of using green energy sources to meet the world''s energy demands, attempts have been made to push perovskite solar cell technology toward industrialization all around the world. Improving the properties of perovskite materials as the heart of PSCs is one of the methods to fabricate favorable photovoltaic (PV) solar cells based on perovskites. Here, cadmium chloride (CdCl2) was used as an additive source for the perovskite precursor to improve its PV properties. Results indicated CdCl2 improves the perovskite growth and tailors its crystalline properties, suggesting boosted charge transport processes in the bulk and interfaces of the perovskite layer with electron–hole transport layers. Overall, by incorporation of 1.0% into the MAPbI3 layer, a maximum power conversion efficiency of 15.28% was recorded for perovskite-based solar cells, higher than the 12.17% for the control devices. The developed method not only improved the PV performance of devices but also boosted the stability behavior of solar cells due to the passivated domain boundaries and enhanced hydrophobicity in the CdCl2-based devices.

With the increase in the importance of using green energy sources to meet the world''s energy demands, attempts have been made to push perovskite solar cell technology toward industrialization all around the world.  相似文献   
109.
INTRODUCTION: The aim of our study was to analyse the role of adrenomedullin (AM) and endothelin-1 (ET-1) in the adaptation of the maternal vascular system in normotensive pregnancy. METHODS: Twenty-eight pregnant women, who were normotensive throughout the duration of their pregnancy, were recruited into the study. Plasma levels of AM and ET-1 at each trimester were measured and the AM/ET-1 ratio was calculated. RESULTS: Our experiment showed a significant decrease in plasma concentrations of AM in the first trimester for the study group (n=28) compared with the non-pregnant control group (n=16). There was also a significant decrease in plasma concentrations of ET-1 in all three trimesters (P<0.05) and a significant increase in the AM/ET-1 ratio in all three trimesters (P<0.05) for the study group compared with the control group. CONCLUSION: An alteration in vascular equilibrium between AM and ET-1, favouring AM, may be a reason why the physiological adaptation of the maternal vascular system to pregnancy occurs during normotensive pregnancy.  相似文献   
110.
Older individuals are more vulnerable to severe coronavirus disease 2019 and medical complications. Vaccination stands as an efficient and safe vanguard against infection. However, negative attitudes and perceptions pertaining to available vaccines might hinder community inoculation. The aim of this study was to assess vaccine hesitancy and its psychosocial determinants among the elderly in Qatar.We conducted a cross-sectional study between October 15 and November 15, 2020, using a composite online survey including the Vaccine Attitudes Examination Scale in addition to questions on sociodemographic correlates and the role of healthcare professionals.The vaccine hesitancy rate was 19.5%. The main reasons for willingness to vaccinate included understanding the nature of disease and role of vaccination, in addition to information provided by physicians. Fears mainly centered around vaccine safety. Vaccine hesitators were more likely to be non-Qatari and having received the influenza vaccine at least once. Gender, marital status, socioeconomic status, educational level, and having completed childhood vaccinations were not associated with vaccine hesitancy.Efforts should be directed toward raising awareness of vaccine efficacy and safety profiles. Physicians should additionally be educated about their pivotal role in advocating vaccine acceptance. We recommend reassessing vaccine hesitancy and its associated factors following a year of campaigning and vaccine administration to identify and target vulnerable groups.  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