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   13779篇
  免费   773篇
  国内免费   126篇
耳鼻咽喉   284篇
儿科学   238篇
妇产科学   336篇
基础医学   2031篇
口腔科学   388篇
临床医学   1139篇
内科学   2748篇
皮肤病学   254篇
神经病学   1070篇
特种医学   638篇
外科学   1865篇
综合类   157篇
一般理论   1篇
预防医学   769篇
眼科学   433篇
药学   1204篇
中国医学   171篇
肿瘤学   952篇
  2023年   97篇
  2022年   246篇
  2021年   466篇
  2020年   205篇
  2019年   330篇
  2018年   433篇
  2017年   303篇
  2016年   393篇
  2015年   579篇
  2014年   643篇
  2013年   859篇
  2012年   1299篇
  2011年   1216篇
  2010年   679篇
  2009年   564篇
  2008年   804篇
  2007年   732篇
  2006年   719篇
  2005年   622篇
  2004年   553篇
  2003年   459篇
  2002年   411篇
  2001年   368篇
  2000年   320篇
  1999年   235篇
  1998年   86篇
  1997年   49篇
  1996年   37篇
  1995年   46篇
  1994年   42篇
  1993年   40篇
  1992年   114篇
  1991年   88篇
  1990年   84篇
  1989年   87篇
  1988年   71篇
  1987年   61篇
  1986年   51篇
  1985年   49篇
  1984年   29篇
  1983年   28篇
  1982年   20篇
  1980年   13篇
  1979年   13篇
  1978年   16篇
  1977年   13篇
  1976年   11篇
  1975年   14篇
  1974年   17篇
  1973年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Colorectal cancer is a common cancer; generally, adults aged ≥ 50 years are screened using stool occult blood tests and colonoscopy. However, colorectal adenoma and cancer have been found in patients under the aged of 50, and studies on characteristics and risk factors in young patients are lacking. We evaluated the prevalence and risk factors of colorectal adenoma and cancer in young adults aged under 50 years.We retrospectively analyzed 570 individuals aged under 50 years who underwent colonoscopy at the Haeundae Paik Hospital, Korea, from January to June 2018. Logistic regression model was used to identify the risk factors for colorectal adenoma and colorectal cancer.The prevalence of colorectal adenoma in group of 19–29 years was 3.2% (1 of 31), 30–39 years was 13.8% (30 of 217) and in the group of 40–49 years was 21.1% (68 of 322) (P = .009). In multivariable analysis, age over 45 years (adjusted odds ratio [OR], 1.941; 95% confidence interval [CI], 1.187–3.172; P = .008) and male sex (adjusted OR, 1.711; 95% CI, 1.044–2.806; P = .033) were independent risk factors for colorectal neoplasia including cancer.The prevalence of colorectal adenoma increases as the age increased in young adults under 50 years of age, especially after the age of 45 years, the risk of colorectal neoplasia increases; hence, early screening should be considered before the age of 50 years.  相似文献   
62.
Rationale:Transvaginal evisceration of the small bowel is an extremely rare condition after hysterectomy, which requires urgent surgical intervention to prevent serious bowel morbidity and mortality.Patient concerns:A 65-year-old woman presented with sudden-onset severe abdominal pain and a mass protruding through the vagina. The past surgical history was significant, with an abdominal hysterectomy for cervical cancer performed 11 weeks prior to presentation.Diagnosis:Pelvic examination revealed prolapsed small-bowel loops (18-20 cm in length). Pelvic computed tomography scan confirmed the presence of transvaginal evisceration of the small bowel.Interventions:Bowel reduction and urgent laparotomy were the selected treatment approaches for a detailed inspection and thorough washing of the intrα-abdominal cavity. A Foley catheter was inserted in the emergency room, with the subject in the lithotomy position. The prolapsed bowel loops spontaneously reduced without manual reduction, and the vault defect was repaired transvaginally.Outcomes:The patient experienced no postoperative complications and remained disease-free for 9months postoperatively.Lessons:Transvaginal evisceration of the small bowel should be considered a surgical emergency. A multidisciplinary approach to prompt case management involving clinicians in gynecology, general surgery, and emergency medicine is vital for preventing serious consequences. Hysterectomy is the most frequently performed gynecological surgical procedure, and evisceration occurs most often after hysterectomy. Therefore, patients should be informed about this rare but possible hysterectomy complication.  相似文献   
63.
64.
Intrahepatic neutrophil infiltration has been implicated in severe alcoholic hepatitis (SAH) pathogenesis; however, the mechanism underlying neutrophil-induced injury in SAH remains obscure. This translational study aims to describe the patterns of intrahepatic neutrophil infiltration and its involvement in SAH pathogenesis. Immunohistochemistry analyses of explanted livers identified two SAH phenotypes despite a similar clinical presentation, one with high intrahepatic neutrophils (Neuhi), but low levels of CD8+ T cells, and vice versa. RNA-Seq analyses demonstrated that neutrophil cytosolic factor 1 (NCF1), a key factor in controlling neutrophilic ROS production, was upregulated and correlated with hepatic inflammation and disease progression. To study specifically the mechanisms related to Neuhi in AH patients and liver injury, we used the mouse model of chronic-plus-binge ethanol feeding and found that myeloid-specific deletion of the Ncf1 gene abolished ethanol-induced hepatic inflammation and steatosis. RNA-Seq analysis and the data from experimental models revealed that neutrophilic NCF1-dependent ROS promoted alcoholic hepatitis (AH) by inhibiting AMP-activated protein kinase (a key regulator of lipid metabolism) and microRNA-223 (a key antiinflammatory and antifibrotic microRNA). In conclusion, two distinct histopathological phenotypes based on liver immune phenotyping are observed in SAH patients, suggesting a separate mechanism driving liver injury and/or failure in these patients.  相似文献   
65.
Phloroglucinol (PG), a polyphenol compound of Eckloniacava known as brown algae abundant in Jeju island, has been proposed to exert the antioxidative and cytoprotective effects against oxidative stress. In this study, we confirmed that PG protected mice from damages caused by ionizing radiation and investigated its protection mechanism in detail. The result showed that PG increased the viability of splenocytes without cytotoxicity. Also, PG significantly enhanced the proliferation of splenocytes by limiting the increment of sub-G1 DNA contents via the inhibition of reactive oxygen species production in 2 Gy-irradiated splenocytes. In addition, PG significantly decreased DNA damage and the number of apoptotic fragments in lymphocytes against oxidative stress. Also, PG increased the counts of endogenous spleen CFUs, compared with only ionizing radiation-irradiated mice. These results demonstrate the multi-faceted protection mechanisms of PG in mice against oxidative stress caused by ionizing radiation, providing the benefit of inhibiting apoptosis and strengthening hematopoiesis.  相似文献   
66.
It is unclear which factors contribute to the developing pressure pain hypersensitivity of the upper trapezius, a type of neurophysiological hyperexcitability. The present study investigated the relationship between physical and psychological factors and pressure pain hypersensitivity of the upper trapezius for each sex. In total, 154 individuals with neck/shoulder myofascial pain participated, among 372 food service workers. Participants completed a questionnaire (Beck Depression Inventory, and Borg Rating of Perceived Exertion scale) and were photographed to measure posture. Pressure pain sensitivity, 2 range of motions (cervical lateral bending and rotation), and 4 muscle strengths (serratus anterior, lower trapezius [LT], biceps, and glenohumeral external rotator) were measured by a pressure algometer, iPhone application, and handheld dynamometer, respectively. For each sex, forward multivariate logistic regression was used to test our a priori hypothesis among selected variables that a combination of psychosocial and physical factors contributed to the risk for pressure pain hypersensitivity. In multivariate analyses, LT strength (odds ratio = 0.94, 95% confidence interval = 0.91–0.97, P = .001) was the only significant influencing factor for pressure pain hypersensitivity in men. Dominant painful ipsilateral cervical rotation range of motion (odds ratio = 0.96, 95% confidence interval = 0.92–0.99, P = .037) was the only influencing factor for pressure pain hypersensitivity in women. LT strength and dominant painful ipsilateral cervical rotation range of motion could serve as guidelines for preventing and managing pressure pain hypersensitivity of the upper trapezius in food service workers with nonspecific neck/shoulder myofascial pain.  相似文献   
67.
68.
Composite regulatory signature database (CRSD), a self-developed comprehensive Web server for composite regulatory signature discovery, used to compare the published microarray data with our data on patients with uterine leiomyoma treated with or without GnRH analogue (GnRH-a), revealed that the focal adhesion, mitogen-activated protein kinase (MAPK), CXC chemokine receptor 4/stromal-derived factor-1 (CXCR4/SDF-1), T-cell receptor, integrin, vascular endothelial growth factor (VEGF), GnRH, and transforming growth factor-beta (TGF-beta) signaling pathways are highly expressed in uterine leiomyoma and significantly down-regulated after GnRH-a treatment. According to the results these signaling pathways could be involved in inflammation, proliferation, and remodeling processes of leiomyoma development and possibly in the regression of leiomyoma after GnRH-a treatment, which might improve our understanding of the mechanisms of leiomyoma formation and help us to find novel drug targets or specific markers for diagnosis and prognosis in uterine leiomyoma.  相似文献   
69.
70.
In early dental plaque formation, oral primary colonizers such as Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus are initially attached to the pellicle-coated tooth surface to form a biofilm. The study aimed to determine the efficacy of macelignan, isolated from nutmeg (Myristica fragrans Houtt.), in removing each single oral primary biofilm in vitro on a polystyrene 96-well microtiter plate. Four biofilm growth phases (4, 12, 20 and 24 h) were evaluated in this study after treatment with macelignan at various concentrations (0.2, 2 and 10 microg/mL) and exposure times (5, 10 and 30 min). Anti-biofilm activity of macelignan was measured as the percentage of the remaining biofilm absorbance after macelignan treatment in comparison with the untreated control. At 24 h of biofilm growth, S. mutans, A. viscosus and S. sanguis biofilms were reduced by up to 30%, 30% and 38%, respectively, after treatment with 10 microg/mL macelignan for 5 min. Increasing the treatment time to 30 min resulted in a reduction of more than 50% of each of the single primary biofilms. The results indicate that macelignan is a potent natural anti-biofilm agent against oral primary colonizers.  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