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排序方式: 共有1321条查询结果,搜索用时 25 毫秒
41.
机械通气作为生命支持和呼吸治疗的有效手段,已广泛应用于临床各个领域,特别是近年来二级甲等医院急诊科建设不断完善、ICU陆续成立,使呼吸机的应用进一步普及。呼吸机报警是机械通气中经常发生的问题,如果处理不当,不仅影响到呼吸机的使用,而且有可能危及到患者的生命,因此正确判断和及时排除报警是极为重要的。对于不是非常熟悉呼吸机应用的临床医护人员对呼吸机报警感到紧张和压力,甚至对报警感到束手无策,不能迅速明确原因,及时正确处理。对呼吸机报警原因进行归纳分析,旨在为临床医护人员处理常见的呼吸机报警提供帮助,进一步提高危重症患者的抢救成功率。  相似文献   
42.
The exact reentrant circuit of verapamil-sensitive idiopathic left ventricular tachycardia (ILVT) remains unclear. This case report demonstrates the reentrant circuit of ILVT. A 20-pole electrode catheter was placed along the left posterior fascicle during electrophysiologic study. ILVT was reproducibly induced by programmed ventricular stimulation. During the tachycardia, sequential diastolic potentials bridging the entire diastolic period were observed in the recordings from the electrodes positioned from left ventricular mid-septum to inferoapical septum. The slow conduction zone appeared to be composed of a false tendon in this patient. Entrainment of the ILVT from the right ventricular outflow tract at a different pacing cycle length revealed that a dominant conduction delay occurred at the proximal site of the slow conduction zone. Entrainment studies from several sites on the left ventricular septum confirmed that these sites where sequential electrical activity was recorded were included within the reentrant circuit. However, the left posterior fascicle itself seemed to be a bystander. This report provides the direct evidence of macroreentry as the underlying mechanism of this ILVT, adjacent to the left posterior fascicle.  相似文献   
43.
Stochastic fluctuations (or “noise”) in the single-cell populations of molecular species are shaped by the structure and biokinetic rates of the underlying gene circuit. The structure of the noise is summarized by its autocorrelation function. In this article, we introduce the noise regulatory vector as a generalized framework for making inferences concerning the structure and biokinetic rates of a gene circuit from its noise autocorrelation function. Although most previous studies have focused primarily on the magnitude component of the noise (given by the zero-lag autocorrelation function), our approach also considers the correlation component, which encodes additional information concerning the circuit. Theoretical analyses and simulations of various gene circuits show that the noise regulatory vector is characteristic of the composition of the circuit. Although a particular noise regulatory vector does not map uniquely to a single underlying circuit, it does suggest possible candidate circuits, while excluding others, thereby demonstrating the probative value of noise in gene circuit analysis.  相似文献   
44.
目的:用多模式的神经电生理检测包括体感诱发电位(SEP)、运动诱发电位(MEP)、肌电图(EMG),以及肌松剂四联刺激肌肉收缩试验(TOF)对脊柱手术监测进行研究,探究检查的方法和对报警的判断.方法:用多模式神经电生理监测方法对120例不同类型脊柱手术进行监测.结果:术中报警67例(63.3%),其中SEP报警46.7%,MEP报警19.1%,EMG报警35.0%.术后均无严重的并发症,并且及时发现了1例术后的血肿压迫并及时予以将其清除.结论:多模式神经电生理监测能最大程度地有效降低脊柱手术的风险.  相似文献   
45.
46.
Fatty acid amide hydrolase (FAAH) regulates tissue concentrations of N‐acylethanolamines (NAEs), including the endocannabinoid, N‐arachidonylethanolamide (anandamide, AEA). FAAH activity and NAEs are widely distributed throughout the brain and FAAH activity regulates an array of processes including emotion, cognition, inflammation, and feeding. However, there is relatively little research describing how this system develops throughout adolescence, particularly within limbic circuits regulating stress and reward processing. Thus, this study characterized temporal changes in NAE content (AEA, oleoylethanolamine [OEA], and palmitoylethanolamide [PEA]) and FAAH activity across the peri‐adolescent period, in four corticolimbic structures (amygdala, hippocampus, prefrontal cortex, and hypothalamus). Brain tissue of male Sprague–Dawley rats was collected on postnatal days (PND) 25, 35, 45, and 70, representing pre‐adolescence, early‐ to mid‐adolescence, late adolescence, and adulthood, respectively. Tissue was analyzed for AEA, OEA, and PEA content as well as FAAH activity at each time point. AEA, OEA, and PEA exhibited a similar temporal pattern in all four brain regions. NAE concentrations were lowest at PND 25 and highest at PND 35. NAE concentrations decreased between PNDs 35 and 45 and increased between PNDs 45 and 70. FAAH activity mirrored the pattern of NAE content in which it decreased between PNDs 25 and 35, increased between PNDs 35 and 45, and decreased between PNDs 45 and 70. These age‐dependent patterns of NAE content and FAAH activity demonstrate temporal specificity to the development of this system and could contribute to alterations in stress sensitivity, emotionality, and executive function which also fluctuate during this developmental period. Synapse, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
47.
目的 探讨小胶质细胞在癫痫中的激活特点及其在癫痫中的作用。方法 将12只Sprague-Dawley(SD)雄性大鼠随机分为对照组和癫痫组,每组各6只; 癫痫组采用氯化锂-匹鲁卡品腹腔注射的方法造模,对照组给予等量生理盐水; 癫痫发作4 d后取大鼠脑组织,采用蛋白质免疫印迹法(Western blot)和免疫组化的方法研究各组电离钙结合适配器分子-1(Ionized calcium binding adaptor molecule 1,Iba1)+小胶质细胞的表达情况。结果 与对照组大鼠模型相比,癫痫组大鼠丘脑皮层环路Iba1的表达增加,小胶质细胞的激活程度增加,且小胶质细胞特异性地在梨状皮质、丘脑室旁核、丘脑外侧背核,腹外侧部分以及腹内侧丘脑核增生。结论 癫痫发作后小胶质细胞的激活和增生存在着明显的脑区选择性,抑制丘脑皮层环路小胶质细胞的激活有望成为癫痫治疗的靶点。  相似文献   
48.
目的 探讨橡胶外科手套固定呼吸回路的应用效果.方法 选取本院收治的80例需上呼吸机患者作为研究对象,随机分为对照组和观察组,各40例.观察组采用橡胶外科手套配合固定,对照组采用呼吸机本身支架调节,比较两组的应用效果.结果 观察组的并发症发生率为0.O%,显著低于对照组的15.0%,差异有统计学意义(P<0.05).观察组的舒适度显著高于对照组,差异有统计学意义(P<0.05).结论 采用橡胶外科手套固定呼吸回路,操作简单,成本较低,值得临床推广使用.  相似文献   
49.
Al-Zn-In alloys having 4.2% zinc content and various indium content in the range of 0.02–0.2% were tested with respect to the most important electrochemical properties of sacrificial anodes in a cathodic protection, i.e., the current capacity and potential of the operating anode. The distribution of In and Zn in the tested alloys was mapped by means of the EDX technique, which demonstrated that these elements dissolve well in the alloy matrix and are evenly distributed within it. The current capacity of such alloys was determined by means of the method of determining the mass loss during the dissolution by a current of known charge. The results obtained demonstrate that the current capacity of Al-Zn-In alloy decreases with the increase in the In content, which results in an increased consumption of anode material and shorter lifetime of anodes. With 0.02% In content, the capacity amounted to approx. 2500 Ah/kg, whereas the alloy with 0.2% In had as much as 30% lower capacity amounting to approx. 1750 Ah/kg. Microscopic examination for the morphology and surface profile of the samples after their exposure demonstrated that a higher indium content in the alloy results in a more uneven general corrosion pattern during the dissolution of such alloy, and the cavities (pits) appearing on the alloy surface are larger and deeper. As the indium content is increased from 0.02% to 0.05%, the Al-Zn-In alloy potential decreases by about 50 mV to −1100 mV vs. Ag/AgCl electrode, which is advantageous in terms of using this alloy as a sacrificial anode. When the indium content is further increased from 0.05% to 0.2%, the potential of the alloy is no longer changed to a more negative one. The results obtained from all these tests demonstrate that alloys containing up to 0.05% of In additive are practically applicable for cathodic protection.  相似文献   
50.
Improper handling of waste printed circuit boards (PCBs) can cause serious pollution to the water and soil environments. In order to explore a new method of recycling waste PCBs, this study investigated the effect of PCBs and butadiene styrene rubber (SBR) on the rheological properties of neat bitumen. The dynamic shear rheological (DSR) test was used to study the effect of different PCB contents on the high-temperature rheological properties of SBR-modified bitumen. Fluorescence microscopy and Fourier-transform infrared spectroscopy were used to study the microstructure change law and modification mechanism of PCB and SBR composite modified bitumen. Finally, the feasibility of the bitumen properties was verified through a test of the bituminous mixture properties. The DSR test results showed that the addition of PCBs improves the elastic recovery modulus, dynamic shear modulus, and rutting factor of SBR-modified bitumen, indicating that the high-temperature properties were improved. Infrared spectroscopy analysis revealed that a new absorption peak was generated in the infrared spectrum of the compound bitumen after the addition of PCBs, and the intensity of the original absorption peak also changed, indicating that PCBs and SBR-modified bitumen were mainly physically blended and accompanied by a weak chemical reaction. It was further found that the absorption peak of the unsaturated C=C double bond was significantly enhanced, and the increase in the content of the unsaturated bond C=C in the main chain of the polymer significantly increases the stiffness of the bitumen. Macroscopically, the high-temperature rutting resistance was improved to a certain extent. The fluorescence diagram shows that when PCBs do not exceed 10%, the PCBs can form a homogeneous structure and be dispersed in SBR-modified bitumen. The road test of PCBs and SBR composite modified bituminous mixtures showed that PCBs can significantly improve the rutting resistance and water stability of SBR-modified bitumen at high temperatures at the recommended optimum content. The crack resistance at low temperatures is weakened but still meets actual engineering requirements. The correlation analysis between the properties of bitumen and bituminous mixtures is carried out based on grey correlation theory. The results show that the index of modified bitumen has a very good guiding effect on the bituminous mixture properties. The development of PCBs and SBR composite-modified bitumen provides a new practical method for recycling waste PCBs.  相似文献   
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