全文获取类型
收费全文 | 5783篇 |
免费 | 295篇 |
国内免费 | 128篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 262篇 |
妇产科学 | 86篇 |
基础医学 | 658篇 |
口腔科学 | 114篇 |
临床医学 | 365篇 |
内科学 | 1167篇 |
皮肤病学 | 95篇 |
神经病学 | 337篇 |
特种医学 | 147篇 |
外国民族医学 | 2篇 |
外科学 | 507篇 |
综合类 | 487篇 |
预防医学 | 593篇 |
眼科学 | 67篇 |
药学 | 775篇 |
中国医学 | 232篇 |
肿瘤学 | 287篇 |
出版年
2023年 | 60篇 |
2022年 | 90篇 |
2021年 | 103篇 |
2020年 | 66篇 |
2019年 | 287篇 |
2018年 | 242篇 |
2017年 | 143篇 |
2016年 | 103篇 |
2015年 | 99篇 |
2014年 | 195篇 |
2013年 | 217篇 |
2012年 | 197篇 |
2011年 | 254篇 |
2010年 | 211篇 |
2009年 | 195篇 |
2008年 | 196篇 |
2007年 | 226篇 |
2006年 | 141篇 |
2005年 | 153篇 |
2004年 | 122篇 |
2003年 | 149篇 |
2002年 | 127篇 |
2001年 | 114篇 |
2000年 | 81篇 |
1999年 | 65篇 |
1998年 | 42篇 |
1997年 | 49篇 |
1996年 | 39篇 |
1995年 | 40篇 |
1994年 | 29篇 |
1993年 | 24篇 |
1992年 | 18篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1989年 | 14篇 |
1988年 | 15篇 |
1987年 | 12篇 |
1985年 | 199篇 |
1984年 | 268篇 |
1983年 | 229篇 |
1982年 | 213篇 |
1981年 | 221篇 |
1980年 | 167篇 |
1979年 | 166篇 |
1978年 | 115篇 |
1977年 | 83篇 |
1976年 | 100篇 |
1975年 | 112篇 |
1974年 | 84篇 |
1973年 | 81篇 |
排序方式: 共有6206条查询结果,搜索用时 15 毫秒
991.
Catherine R. Sears 《Respiratory investigation》2019,57(2):111-121
Cigarette smoking is the leading cause of lung cancer and chronic obstructive pulmonary disease (COPD). Many of the detrimental effects of cigarette smoke have been attributed to the development of DNA damage, either directly from chemicals contained in cigarette smoke or as a product of cigarette smoke-induced inflammation and oxidative stress. In this review, we discuss the environmental, epidemiological, and physiological links between COPD and lung cancer and the likely role of DNA damage and repair in COPD and lung cancer development. We explore alterations in DNA damage repair by DNA repair proteins and pathways. We discuss emerging data supporting a key role for the DNA repair protein, xeroderma pigmentosum group C (XPC), in cigarette smoke-induced COPD and early lung cancer development. Understanding the interplay between cigarette smoke, DNA damage repair, COPD, and lung cancer may lead to prognostic tools and new, potentially targetable, pathways for lung cancer prevention and treatment. 相似文献
992.
Talkington D Bopp C Tarr C Parsons MB Dahourou G Freeman M Joyce K Turnsek M Garrett N Humphrys M Gomez G Stroika S Boncy J Ochieng B Oundo J Klena J Smith A Keddy K Gerner-Smidt P 《Emerging infectious diseases》2011,17(11):2122-2129
In October 2010, the US Centers for Disease Control and Prevention received reports of cases of severe watery diarrhea in Haiti. The cause was confirmed to be toxigenic Vibrio cholerae, serogroup O1, serotype Ogawa, biotype El Tor. We characterized 122 isolates from Haiti and compared them with isolates from other countries. Antimicrobial drug susceptibility was tested by disk diffusion and broth microdilution. Analyses included identification of rstR and VC2346 genes, sequencing of ctxAB and tcpA genes, and pulsed-field gel electrophoresis with SfiI and NotI enzymes. All isolates were susceptible to doxycycline and azithromycin. One pulsed-field gel electrophoresis pattern predominated, and ctxB sequence of all isolates matched the B-7 allele. We identified the tcpETCIRS allele, which is also present in Bangladesh strain CIRS 101. These data show that the isolates from Haiti are clonally and genetically similar to isolates originating in Africa and southern Asia and that ctxB-7 and tcpET(CIRS) alleles are undergoing global dissemination. 相似文献
993.
Sjölund-Karlsson M Reimer A Folster JP Walker M Dahourou GA Batra DG Martin I Joyce K Parsons MB Boncy J Whichard JM Gilmour MW 《Emerging infectious diseases》2011,17(11):2151-2154
To increase understanding of drug-resistant Vibrio cholerae, we studied selected molecular mechanisms of antimicrobial drug resistance in the 2010 Haiti V. cholerae outbreak strain. Most resistance resulted from acquired genes located on an integrating conjugative element showing high homology to an integrating conjugative element identified in a V. cholerae isolate from India. 相似文献
994.
995.
996.
997.
BackgroundDistal pancreatectomy with celiac axis resection (DP-CAR) is a procedure to secure a surgical margin for a locally advanced pancreatic body cancer that invades the celiac axis. However, in patients with cancer close to the root of the celiac axis, obtaining adequate surgical margins can be difficult because the tumor obstructs the field of vision to the root of the celiac axis. Previously, we described the retroperitoneal-first laparoscopic approach (Retlap) to achieve both accurate evaluation of resectability for locally advanced pancreatic cancer requiring DP-CAR [1] and adequate surgical margin for laparoscopic distal pancreatectomy [2]. In this video, we introduce Retlap-assisted DP-CAR as a minimally invasive approach for performing an artery-first pancreatectomy [3, 4] and achieving sufficient dorsal surgical margin (Fig. 1).MethodsOur patient is a 67-year-old man with a 55 × 29-mm pancreatic body tumor after chemotherapy. Preoperative computed tomography revealed a tumor close to the root of the celiac axis. Because the area of tumor invasion on preoperative images was near the root of the celiac artery, Retlap-assisted DP-CAR was performed to determine whether the celiac axis can be secured and obtain an adequate dorsal surgical margin (Fig. 2).ResultsThe operative time and estimated blood loss was 715 min and 449 mL, respectively. In spite of the advanced tumor's location and size, R0 resection was achieved in a minimally invasive way.ConclusionRetlap-assisted DP-CAR is not only technically feasible and useful for achieving accurate evaluation of resectability but also facilitates obtaining an adequate surgical margin. 相似文献
998.
《Journal of stroke and cerebrovascular diseases》2022,31(6):106469
ObjectiveTo compare corticospinal excitability and transcallosal inhibition between contralesional primary motor cortex (M1) and ipsilesional M1. We also investigated the correlation between transcallosal inhibition and upper extremity motor behavior.Materials and methods19 individuals with unilateral ischemic subacute stroke who had severe upper extremity impairment participated in this study. Corticospinal excitability was assessed by measuring the resting motor threshold, active motor threshold and motor evoked potential amplitude. Transcallosal inhibition was investigated by measuring the duration and depth of the ipsilateral silent period (ISP). The data from the two hemispheres were compared and the relationships of transcallosal inhibition with upper extremity motor impairment, grip strength and pinch strength were analyzed.ResultsResting motor threshold (p = 0.001) and active motor threshold (p = 0.001) were lower and motor evoked potential amplitude was higher (p = 0.001) in the contralesional M1 compared to the ipsilesional M1. However, there were no differences between the two M1s in ISP duration (p = 0.297) or ISP depth (p =0. 229). Transcallosal inhibition from the contralesional M1 was positively associated with motor impairment (ISP duration, p = 0.003; ISP depth, p = 0.017) and grip strength (ISP duration, p = 0.016; ISP depth, p = 0.045).ConclusionsSymmetric transcallosal inhibition between hemispheres and positive association of transcallosal inhibition from contralesional M1 with upper extremity motor behavior indicate that recruitment of contralesional M1 may be necessary for recovery in patients with severe upper extremity impairment after subacute ischemic stroke. 相似文献
999.
《The Journal of thoracic and cardiovascular surgery》2023,165(2):591-604.e3
ObjectivesGuidelines suggest aortic valve replacement (AVR) for low-risk asymptomatic patients. Indications for transcatheter AVR now include low-risk patients, making it imperative to understand state-of-the-art surgical AVR (SAVR) in this population. Therefore, we compared SAVR outcomes in low-risk patients with those expected from Society of Thoracic Surgeons (STS) models and assessed their intermediate-term survival.MethodsFrom January 2005 to January 2017, 3493 isolated SAVRs were performed in 3474 patients with STS predicted risk of mortality <4%. Observed operative mortality and composite major morbidity or mortality were compared with STS-expected outcomes according to calendar year of surgery. Logistic regression analysis was used to identify risk factors for these outcomes. Patients were followed for time-related mortality.ResultsWith 15 observed operative deaths (0.43%) compared with 55 expected (1.6%), the observed:expected ratio was 0.27 for mortality (95% confidence interval [CI], 0.14-0.42), stroke 0.65 (95% CI, 0.41-0.89), and reoperation 0.50 (95% CI, 0.42-0.60). Major morbidity or mortality steadily declined, with probabilities of 8.6%, 6.7%, and 5.2% in 2006, 2011, and 2016, respectively, while STS-expected risk remained at approximately 12%. Mitral valve regurgitation, ventricular hypertrophy, pulmonary, renal, and hepatic failure, coronary artery disease, and earlier surgery date were residual risk factors. Survival was 98%, 91%, and 82% at 1, 5, and 9 years, respectively, superior to that predicted for the US age-race-sex–matched population.ConclusionsSTS risk models overestimate contemporary SAVR risk at a high-volume center, supporting efforts to create a more agile quality assessment program. SAVR in low-risk patients provides durable survival benefit, supporting early surgery and providing a benchmark for transcatheter AVR. 相似文献
1000.