全文获取类型
收费全文 | 3487篇 |
免费 | 281篇 |
国内免费 | 108篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 174篇 |
妇产科学 | 81篇 |
基础医学 | 491篇 |
口腔科学 | 57篇 |
临床医学 | 371篇 |
内科学 | 797篇 |
皮肤病学 | 26篇 |
神经病学 | 229篇 |
特种医学 | 116篇 |
外科学 | 510篇 |
综合类 | 67篇 |
一般理论 | 2篇 |
预防医学 | 178篇 |
眼科学 | 104篇 |
药学 | 239篇 |
中国医学 | 9篇 |
肿瘤学 | 377篇 |
出版年
2023年 | 17篇 |
2022年 | 47篇 |
2021年 | 79篇 |
2020年 | 46篇 |
2019年 | 65篇 |
2018年 | 64篇 |
2017年 | 58篇 |
2016年 | 68篇 |
2015年 | 76篇 |
2014年 | 109篇 |
2013年 | 143篇 |
2012年 | 204篇 |
2011年 | 200篇 |
2010年 | 110篇 |
2009年 | 118篇 |
2008年 | 162篇 |
2007年 | 244篇 |
2006年 | 189篇 |
2005年 | 202篇 |
2004年 | 167篇 |
2003年 | 174篇 |
2002年 | 151篇 |
2001年 | 153篇 |
2000年 | 116篇 |
1999年 | 103篇 |
1998年 | 51篇 |
1997年 | 30篇 |
1996年 | 45篇 |
1995年 | 35篇 |
1994年 | 26篇 |
1993年 | 24篇 |
1992年 | 75篇 |
1991年 | 59篇 |
1990年 | 44篇 |
1989年 | 48篇 |
1988年 | 46篇 |
1987年 | 49篇 |
1986年 | 43篇 |
1985年 | 32篇 |
1984年 | 28篇 |
1983年 | 20篇 |
1982年 | 14篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1977年 | 12篇 |
1976年 | 16篇 |
1974年 | 12篇 |
1973年 | 10篇 |
排序方式: 共有3876条查询结果,搜索用时 15 毫秒
91.
Chen TY Chen CL Huang TL Tsang LL Wang CC Wang SH Yang CH Concejero AM Cheng YF 《Clinical transplantation》2006,20(6):725-731
BACKGROUND AND OBJECTIVES: Graft harvest with or without the middle hepatic vein (MHV) affects venous return and function of the remaining liver. The aims of this study are to compare the remnant liver volume and spleen changes in the donors of different types of graft harvest and to evaluate the influence of resection with or without the MHV on the remnant liver volume regeneration, spleen volume change and serum total bilirubin. PATIENTS AND METHODS: A total of 165 donors were grouped according to the type of graft harvest: 88 donors underwent left lateral segmentectomy (LLS), 10 donors underwent extend LLS or left lobectomy (LL), and 67 donors underwent right lobectomy (RL). Groups LLS and LL were later combined as group LH (left hepatectomy, n = 98). There were 68 men and 97 women. The mean age was 32.9 +/- 8.1 yr. The total liver volume (LV) and spleen volume (S1) before graft harvest, graft weight (GW), regenerated liver volume (LV(6m)) and spleen volume (S2) six months post-donation were calculated. RESULTS: There were no significant differences in the regenerated liver volume six months postoperation (LV(6m)) and recovery ratio (LV(6m)/LV x 100%) among the different groups, albeit significant smaller LV(6m) in both groups compared with the initial liver volume was noted. Postoperative spleen volume (S2), average spleen ratio (S2/S1) and spleen change ratio were significantly larger and higher in group RL than in group LH. A significant increase in spleen volume was noted in both groups six months after graft harvest. A significantly higher TB in group RL (4.1 +/- 1.7 mg/dL, range: 1.4-8.5 mg/dL) was noted compared with that of group LH (1.6 +/- 1.0 mg/dL, range: 0.7-6.2 mg/dL). CONCLUSION: There was a significant increase in the regenerated remnant liver and splenic volumes six months postoperation in all types of hepatectomy following living donor hepatectomy, and there was no difference in the mean TB levels among donors whether the MHV was included or not in the graft. 相似文献
92.
Rationale:Tumor lysis syndrome is a potentially lethal condition caused by rapid cell death, releasing a high level of toxic cytokines. It is common in patients with hematological malignancy but rare in solid tumors.Patient concerns:A 64-year-old patient presented to our unit with a 17.3-cm hepatocellular carcinoma and marginal liver reserve. The first-stage operation of associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) was performed.Diagnosis:The patient was found to be anuric with grossly deranged electrolytes after the first-stage operation. Tumor lysis syndrome was diagnosed.Interventions:The patient was transferred to the intensive care unit for aggressive fluid administration and continuous venovenous hemofiltration for the management of tumor lysis syndrome.Outcomes:The patient recovered and then underwent the second-stage operation of ALPPS with extended right hepatectomy 8 days after the initial operation without any long-term sequelae.Lessons:ALPPS is a relatively new technique in liver surgery, entailing an increased risk of tumor lysis syndrome due to an in situ tumor after the first-stage operation. Clinicians should have a high index of suspicion regarding this potentially lethal complication with prompt management. 相似文献
93.
Christina L. Luong Kevin Ong Kendeep Kaila Patricia A. Pellikka Kenneth Gin Teresa S. M. Tsang 《Journal of ultrasound in medicine》2019,38(4):865-876
Focused cardiac ultrasonography is performed by clinicians at the bedside and is used in time‐sensitive scenarios to evaluate a patient's cardiovascular status when comprehensive echocardiography is not immediately available. This simplified cardiac ultrasonography is often performed by noncardiologists using small, portable devices to augment the physical examination, triage patients, and direct management in both critical care and outpatient settings. However, as the use of focused cardiac ultrasonography continues to expand, careful consideration is required regarding training, scope of practice, impact on patient outcomes, and medicolegal implications. In this review, we examine some of the challenges with rapid uptake of this technique and explore the benefits and potential risk of focused cardiac ultrasonography. We propose possible mechanisms for cross‐specialty collaboration, quality improvement, and oversight. 相似文献
94.
Tsang KW Tipoe GL Mak JC Sun J Wong M Leung R Tan KC MedStat CK Ho JC Ho PL Rutman A Lam WK 《Respiratory medicine》2005,99(3):290-297
It has been suggested that patients with bronchiectasis might have increased central microtubular orientation angle (CMOA), which leads to poor coordination of ciliary beating, and consequently impairment of airway defence. We have employed transmission electron microscopy to assess CMOA of ciliated nasal mucosa in a cohort of 133 (81F, 56.8+/-16.1yr) stable bronchiectasis and 59 healthy subjects (30F, 49.3+/-22.1yr). There was no significant difference in CMOA between bronchiectasis (13.2 degree) and control subjects (13.0 degree, P=0.82). There was no significant difference in CMOA among patients according to the etiology of bronchiectasis, presence of nasal symptoms, or sputum status of Pseudomonas aeruginosa infection. Patients with more severe bronchiectasis, i.e. those with FEV(1) <60%, FVC <60%, or more than 4 bronchiectatic lung lobes, had significantly lower CMOA than their counterparts (P<0.05). There was no correlation between CMOA with age, 24h sputum volume, exacerbation frequency, FEV(1), FVC, or the number of bronchiectatic lung lobes (P>0.05). CMOA correlated with ciliary beat frequency (negative), and the percent of cilia showing ultrastructural or microtubular defects (P<0.05). Central microtubular orientation angle does not correlate with clinically important parameters, in contrary to the results reported by previously published smaller scale studies. 相似文献
95.
目的:近年细胞培养实验发现他汀类药物可以促进骨形成,采用动物实验观察胰岛素和他汀类药物立普妥对糖尿病大鼠骨代谢的影响,为糖尿病伴骨质疏松的治疗提供实验依据。方法:实验于2005-08/2006-01在大连医科大学病理教研室完成。①实验分组:SD雄性大鼠55只,随机选择10只为空白对照组,余45只经鼠尾静脉注射链尿佐菌素造成糖尿病大鼠模型。其中40只符合造模标准,随机分为糖尿病未治疗组、胰岛素治疗组、立普妥治疗组及胰岛素 立普妥治疗组,每组10只。②实验方法:所有大鼠皆给予相同普通饮食。胰岛素治疗组及胰岛素 立普妥治疗组于实验第4天接受中效胰岛素治疗,6~8U/d分两次颈背部皮下注射。胰岛素剂量按每只鼠每周血糖进行调整。立普妥治疗组及胰岛素 立普妥治疗组于实验第4天给予立普妥1.25mg/kg灌胃。糖尿病未治疗组和空白对照组给予等量生理盐水灌胃。③实验评估:9周末用乙醚麻醉,每组取4只大鼠去眼球取血之后处死。14周末应用同样方法处死剩余大鼠。均取腰椎骨,常规脱钙石蜡包埋,行苏木精-伊红染色。骨组织形态计量学测量平均骨小梁厚度和平均骨小梁间距或弥散度。血中Ⅰ型胶原氨基端肽测定采用竞争性放射免疫检测方法(碘标记)。结果:实验期间大鼠死亡5只,其中糖尿病未治疗组1只于第3周死亡,胰岛素组2只于第6周死亡,胰岛素 立普妥治疗组2只于第7周死亡。①骨组织病理形态学变化:9周末立普妥治疗组、胰岛素 立普妥治疗组及糖尿病未治疗组光镜下见骨质疏松表现。14周末立普妥治疗组及胰岛素治疗组骨组织微观结构恢复至空白对照组水平。②平均骨小梁厚度:9周末:糖尿病未治疗组、胰岛素治疗组、立普妥治疗组及胰岛素 立普妥治疗组均明显低于空白对照组(P<0.01)。14周末:糖尿病未治疗组及胰岛素 立普妥治疗组均明显低于空白对照组(P<0.05)。③平均骨小梁间距或弥散度:9周末:糖尿病未治疗组及胰岛素 立普妥治疗组均明显高于空白对照组(P<0.05)。14周末:糖尿病未治疗组及胰岛素 立普妥治疗组均明显高于空白对照组(P<0.05)。④Ⅰ型胶原氨基端肽水平:9周末:立普妥治疗组和胰岛素 立普妥治疗组均明显高于空白对照组(P<0.01)。14周末:胰岛素治疗组、立普妥治疗组和胰岛素 立普妥治疗组均明显高于空白对照组(P<0.01)。结论:①糖尿病大鼠造模9周出现明显的骨质疏松。②糖尿病大鼠骨质变化表现为骨吸收超过骨形成作用,主要以骨吸收增强为主。③立普妥及胰岛素可以促进糖尿病大鼠骨质的形成,抑制糖尿病大鼠骨质疏松的发生发展。 相似文献
96.
97.
98.
Tsang SW Pomakian J Marshall GA Vinters HV Cummings JL Chen CP Wong PT Lai MK 《Neurobiology of aging》2007,28(9):1381-1387
There are few studies on the clinical and neurochemical correlates of postsynaptic cholinergic dysfunction in Alzheimer's disease (AD). We have previously found that attenuation of guanine nucleotide-binding (G-) protein coupling to muscarinic M(1) receptors in the neocortex was associated with dementia severity. The present study aims to study whether this loss of M(1)/G-protein coupling is related to alterations in signaling kinases and NMDA receptors. Postmortem frontal cortices of 22 AD subjects and 12 elderly controls were obtained to measure M(1) receptors, M(1)/G-protein coupling, NMDA receptors as well as protein kinase C (PKC) and Src kinase activities. We found that the extent of M(1)/G-protein coupling loss was correlated with reductions in PKC activity and NMDA receptor density. In contrast, Src kinase activity was neither altered nor associated with M(1)/G-protein coupling. Given the well established roles of neuronal PKC signaling and NMDA receptor function in cognitive processes, our results lend further insight into the mechanisms by which postsynaptic cholinergic dysfunction may underlie the cognitive features of AD, and suggest alternative therapeutic targets to cholinergic replacement. 相似文献
99.
Kam KM Luey CK Tsang YM Law CP Chu MY Cheung TL Chiu AW 《Journal of clinical microbiology》2003,41(10):4502-4511
Two hundred twenty isolates of Vibrio cholerae O1 and O139 collected from 1994 to 2002 in Hong Kong were analyzed by pulsed-field gel electrophoresis (PFGE). Chromosomal DNAs from all V. cholerae isolates in agarose plugs were digested with the restriction enzyme NotI, resulting in 20 to 27 bands. Sixty distinctive PFGE patterns in the range of 10 to 300 kb were noted among 213 isolates typeable by PFGE. By comparing the common PFGE patterns obtained from four well-defined outbreaks of V. cholerae O1 and O139 with those obtained from other, epidemiologically unrelated isolates during the study period, indistinguishable and similar PFGE patterns were identified, indicating their close relatedness, in agreement with the results of epidemiological investigations. Heterogeneous PFGE patterns (with four to six banding differences), however, were identified among strains that were imported from other parts of Asia, including Indonesia, India, and Pakistan. Correlations with epidemiological information further support the usefulness of PFGE as an epidemiological tool in laboratory investigations of suspected outbreaks. Standardization of PFGE methodology will allow international comparison of fingerprint patterns and will form the basis of a laboratory network for tracking V. cholerae. 相似文献
100.
Neisseria meningitidis is the causative agent of meningococcal sepsis and meningitis. Neisseria polysaccharea is a nonpathogenic species. N. polysaccharea is able to use sucrose to produce amylopectin, a starch-like polysaccharide, which distinguishes it biochemically from the pathogenic species N. meningitidis. The data presented here indicate that this may be an insufficient criterion to distinguish between these two species. The nonencapsulated Neisseria strain 93246 expressed a phenotype of amylopectin production similar to that of N. polysaccharea. However, strain 93246 reacted with N. meningitidis serotype 4 and serosubtype P1.14 monoclonal antibodies and showed the N. meningitidis L1(8) lipo-oligosaccharide immunotype. Further analyses were performed on four genetic loci in strain 93246, and the results were compared with 7 N. meningitidis strains, 13 N. polysaccharea strains, and 2 N. gonorrhoeae strains. Three genetic loci, opcA, siaD, and lgt-1 in strain 93246, were the same as in N. meningitidis. Particularly, the siaD gene encoding polysialyltransferase responsible for biosynthesis of N. meningitidis group B capsule was detected in strain 93246. This siaD gene was inactivated by a frameshift mutation at the poly(C) tract, which makes strain 93246 identical to other nonencapsulated N. meningitidis strains. As expected, the ams gene encoding amylosucrase, responsible for production of amylopectin from sucrose, was detected in strain 93246 and all 13 N. polysaccharea strains but not in N. meningitidis and N. gonorrhoeae strains. These data suggest that strain 93246 is nonencapsulated N. meningitidis but has the ability to produce extracellular amylopectin from sucrose. The gene for amylopectin production in strain 93246 was likely imported from N. polysaccharea by horizontal genetic exchange. Therefore, we conclude that genetic analysis is required to complement the traditional phenotypic classification for the nonencapsulated Neisseria strains. 相似文献