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排序方式: 共有4827条查询结果,搜索用时 15 毫秒
101.
Amir Hossein Baghdadi Zainuddin Sajuri Azadeh Keshtgar Nurulakmal Mohd Sharif Armin Rajabi 《Materials》2022,15(1)
The 5083 and 6061(T6) aluminum (Al) alloys are widely used in transportation industries and the development of structural designs because of their high toughness and high corrosion resistance. Friction stir welding (FSW) was performed to produce the dissimilar welded joint of Al5083-Al 6061(T6) under different welding parameters. However, softening behavior occurred in the friction stir welded (FSWed) samples because of grain coarsening or the dissolution of precipitation-hardening phases in the welding zone. Consequently, this research intended to investigate the effect of the post-weld heat treatment (PWHT) method on the mechanical property improvement of the dissimilar FSWed Al5083-Al6061(T6) and governing abnormal grain growth (AGG) through different welding parameters. The results showed PWHT enhanced the mechanical properties of dissimilar joints of Al5083-Al6061(T6). AGG was obtained in the microstructure of PWHTed joints, but appropriate PWHT could recover the dissolved precipitation-hardening particle in the heat-affected zone of the as-welded joint. Further, the tensile strength of the dissimilar joint increased from 181 MPa in the as-welded joint to 270 MPa in the PWHTed joint, showing 93% welding efficacy. 相似文献
102.
Seyed Hossein Mohseni Salehi Monfared Gholamreza Shirani Neda Moslemi Faranak Noori Amir Raee 《Clinical Case Reports》2022,10(2)
Shallow lingual vestibule and lack of keratinized attached mucosa are considered risk factors for the long‐term success of dental implants. This article describes a modified surgical approach accompanied by a free gingival graft to correct the shallow lingual/buccal vestibule and to increase the keratinized tissue around dental implants. 相似文献
103.
After the initial study of different protocols in the synthesis of indeno[2′,1′:5,6]pyrido[2,3-d]pyrimidines, herein, a new method is presented using cheaper and more accessible starting materials to produce high-efficiency products. In this protocol, the novel nanocatalyst is very effective in the progression of the reaction and increasing the efficiency. This green approach in aqueous media has several advantages as compared with other methods, such as easier work-up, very mild reaction conditions, reusability of the catalyst, and eco-friendliness. The products of this four-component condensation were evaluated using IR, 1H NMR, 13C NMR spectra, and C. H. N. analyses, and the catalyst structure was confirmed by FT-IR, XRD, SEM, EDX, TGA and VSM techniques.In this protocol, a novel nanocatalyst was very effective in progression of the reaction and increasing efficiency. This green approach in aqueous media has several advantages compared with the reported methods. 相似文献
104.
This work aimed at developing a natural compound-based hydrogel adsorbent to remove diclofenac as a model pharmaceutical from water. First, graphene oxide–chitosan (GO–CTS) and amine graphene oxide–chitosan (AGO–CTS) hydrogel adsorbents were synthesized via a facile mechanical mixing method. The synthesized materials were characterized through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning and transmission electron microscopy (SEM and TEM), Raman spectroscopy, and thermogravimetric analysis (TGA) techniques. In the second stage, adsorption experiments were conducted to determine the best GO to CTS ratio and find the optimized adsorption parameters, including the initial drug concentration, adsorbent dosage, pH, and temperature. The results showed that the optimal GO to CTS mass ratio is 2 : 5 and thus the same ratio was selected as the AGO to CTS mass ratio to understand the effect of amine-functionalization on removal efficiency. The optimal adsorption parameters were determined to be pH of 5, Ci of 100 ppm and dosage of 1.5 g L−1, where 90.42% and 97.06% removal was achieved for optimal GO–CTS and AGO–CTS hydrogel adsorbents, respectively. Langmuir and Freundlich isotherms models were employed to investigate the adsorption behavior of diclofenac onto the synthesized hydrogels. The results revealed that the adsorption tends to be of the monolayer type and homogeneous, as the results were in better accordance with the Langmuir model than the Freundlich model. The thermodynamics of adsorption demonstrated that the adsorption is exothermic, exhibiting higher removal efficiency at lower temperatures. Furthermore, Gibb''s free energy change of adsorption (ΔG) suggested that the adsorption is spontaneous, being more spontaneous for AGO–CTS than GO–CTS hydrogels. Finally, the regeneration ability of the hydrogel adsorbents was studied in five consecutive cycles. The adsorbent maintained its efficiency at a relatively high level for three cycles but a considerable decrease was observed between the third and the fourth cycle, indicating that the hydrogels were recoverable for three cycles.This work aimed at developing a natural compound-based hydrogel adsorbent to remove diclofenac as a model pharmaceutical from water. 相似文献
105.
106.
Nano polymeric micelles (nano PMs) help to increase accessibility to tumor sites, decrease side effects and allow controlled drug dissemination over a long period of time. The aim of this study was to optimize the delivery of the anticancer drug capecitabine (CAP) using nano PMs and cyclodextrin (CD) to allow the treatment of colon cancer. A pH-responsive copolymer was prepared and the variables of loading time, loading temperature, the amount of copolymer and also the ratio of acrylic/maleic copolymer to beta CD and the effect that these variables have on drug loading were investigated, with variable optimization studies carried out following a definitive screening design (DSD). The morphology and structure of the particles were determined by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy. In vitro drug release exemplified that the micelles were pH-sensitive, this action was shown that firstly the drug release was done perfectly targeted and under control and secondly the drug has been released above 80% inside the colon.Nano polymeric micelles (nano PMs) help to increase accessibility to tumor sites, decrease side effects and allow controlled drug dissemination over a long period of time. 相似文献
107.
Mohammad Meskarpour-Amiri Hossein Amini Ali Mehrabi Tavana 《Asian Pacific journal of tropical medicine》2021,(4):157-158
Given the failure to find a definitive cure for COVID-19,the only hopes for controlling the pandemic right now are vaccine production and universal vaccination.Therefore,vaccine is vital to the prevention and control of COVID-19 outbreak and it will support global health security. 相似文献
108.
Getaw Worku Hassen Ana Costea Tennyson Smith Claire Carrazco Hafiz Hussein Bahareh Soroori-Rad Sonia Vaidian Justin Seashore Edris Alderwish Wei Sun Alice Chen Bonnie Simmons Shakeel Usmani Hossein Kalantari George Fernaine 《The Journal of emergency medicine》2014
Background
The electrocardiogram (ECG) is the most important diagnostic tool for acute myocardial infarction (AMI). T wave inversion (TWI) in lead aVL has not been emphasized or well recognized.Objective
This study examined the relationship between the presence of TWI before the event and mid-segment left anterior descending (MLAD) artery lesion in patients with AMI.Methods
Retrospective charts of patients with acute coronary syndrome between the months of January 2009 and December 2011 were reviewed. All patients with MLAD lesion were identified and their ECG reviewed for TWI in lead aVL.Results
Coronary angiography was done on 431 patients. Of these, 125 (29%) had an MLAD lesion. One hundred and six patients (84.8%) had a lesion > 50% and 19 patients (15.2%) had a lesion < 50%. Of the 106 patients who had a MLAD lesion > 50%, 90 patients (84.9%) had TWI in lead aVL and one additional lead. Of the 19 patients who had an MLAD lesion < 50%, 8 patients (42.1%) had TWI in lead aVL and one additional lead. Isolated TWI in lead aVL had an overall sensitivity of 76.7% (95% confidence interval [CI] 0.65–0.86), a specificity of 71.4% (95% CI 0.45–0.88), a positive predictive value of 92%, a negative predictive value of 41.7%, a positive likelihood ratio of 2.7 (95% CI 1.16–6.22), and negative likelihood ratio of 0.32 (95% CI 0.19–0.58) for predicting a MLAD lesion of > 50% (p = 0.0011).Conclusions
TWI in lead aVL might signify a mid-segment LAD lesion. Recognition of this finding and early appropriate referral to a cardiologist might be beneficial. Additional studies are needed to validate this finding. 相似文献109.
Shahram Paydar Ali Taheri Akerdi Sadra Nikseresht Hossein Abdolrahimzadeh-Far Leila Shayan Zahra Ghahramani Shahram Bolandparvaz Hamid Reza Abbasi 《中华创伤杂志(英文版)》2021,24(1):30-33
Purpose Traumatic hemorrhagic shock is a life-threatening event worldwide.Severe brain trauma accompanying femoral fractures can trigger inflammatory responses in the body and increase pre-inflammatory cytokines such as TNF-α,IL-1.The primary treatment in these cases is hydration with crystalloids,which has both benefits and complications.The purpose of this study was to investigate the effects of fluid therapy on the hemodynamics,coagulation profiles,and blood gases in such patients.Methods In this cross-sectional study,patients were divided into two groups:femoral fracture group and non-femoral group.The hemodynamic status,coagulation profile,and blood gases of patients in both groups were evaluated upon arrival at the hospital and again 2 h later.Data were analyzed by t-test and ANOVA with repeated data and paired samples t-test.Results A total of 681 trauma patients(605 men and 76 women)participated in this study,including 69(86.3%)men and 11(13.8%)women in femoral fracture group and 536 men(89.2%)and 65 women(10.8%)in non-femoral group.The laboratory parameters were evaluated in response to the equal amount of crystalloid fluid given upon arrival and 2 h later.Blood gases decreased in the fracture group despite fluid therapy(p<0.003),and the coagulation profile worsened although the change was not statistically significant.Conclusion The treatment of multiple-trauma patients with femoral bone fractures should be more concerned with the need for the infusion of vasopressors such as norepinephrine.If there is evidence of clinical shock,excessive crystalloid infusion(limited to 1 L)should be avoided,and blood and blood products should be started as soon as possible. 相似文献
110.
Elham Khodaverdi Hossein Ali Soleimani Fatemeh Mohammadpour Farzin Hadizadeh 《Chemical biology & drug design》2016,87(6):849-857
Scientists have always been trying to use artificial zeolites to make modified‐release drug delivery systems in the gastrointestinal tract. An ideal carrier should have the capability to release the drug in the intestine, which is the main area of absorption. Zeolites are mineral aluminosilicate compounds with regular structure and huge porosity, which are available in natural and artificial forms. In this study, soaking, filtration and solvent evaporation methods were used to load the drugs after activation of the zeolites. Weight measurement, spectroscopy FTIR, thermogravimetry and scanning electronic microscope were used to determine drug loading on the systems. Finally, consideration of drug release was made in a simulated gastric fluid and a simulated intestinal fluid for all matrixes (zeolites containing drugs) and drugs without zeolites. Diclofenac sodium (D) and piroxicam (P) were used as the drug models, and zeolites X and Y as the carriers. Drug loading percentage showed that over 90% of drugs were loaded on zeolites. Dissolution tests in stomach pH environment showed that the control samples (drug without zeolite) released considerable amount of drugs (about 90%) within first 15 min when it was about 10–20% for the matrixes. These results are favorable as NSAIDs irritate the stomach wall and it is ideal not to release much drugs in the stomach. Furthermore, release rate of drugs from matrixes has shown slower rate in comparison with control samples in intestine pH environment. 相似文献