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   15372篇
  免费   1004篇
  国内免费   199篇
耳鼻咽喉   218篇
儿科学   341篇
妇产科学   737篇
基础医学   1962篇
口腔科学   273篇
临床医学   1603篇
内科学   3266篇
皮肤病学   378篇
神经病学   936篇
特种医学   539篇
外科学   2334篇
综合类   428篇
现状与发展   2篇
一般理论   3篇
预防医学   765篇
眼科学   288篇
药学   1097篇
中国医学   105篇
肿瘤学   1300篇
  2023年   80篇
  2022年   236篇
  2021年   437篇
  2020年   225篇
  2019年   332篇
  2018年   423篇
  2017年   295篇
  2016年   294篇
  2015年   462篇
  2014年   591篇
  2013年   740篇
  2012年   1111篇
  2011年   1095篇
  2010年   718篇
  2009年   589篇
  2008年   877篇
  2007年   896篇
  2006年   812篇
  2005年   825篇
  2004年   702篇
  2003年   580篇
  2002年   544篇
  2001年   475篇
  2000年   414篇
  1999年   352篇
  1998年   149篇
  1997年   117篇
  1996年   101篇
  1995年   79篇
  1994年   76篇
  1993年   52篇
  1992年   181篇
  1991年   172篇
  1990年   148篇
  1989年   130篇
  1988年   113篇
  1987年   128篇
  1986年   107篇
  1985年   92篇
  1984年   77篇
  1983年   60篇
  1980年   41篇
  1979年   58篇
  1978年   51篇
  1977年   45篇
  1976年   43篇
  1975年   41篇
  1974年   47篇
  1972年   59篇
  1971年   35篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Kirsten rat sarcoma (KRAS) mutation (KRASm) is associated with poor prognosis in non-small cell lung cancer (NSCLC) patients. We have aimed to survey NSCLC patients harboring KRASm in Taiwan, where never-smoking lung adenocarcinoma predominates, and analyze the immune checkpoint inhibitor effect on NSCLC harboring KRASm.NSCLC patients with KRASm were enrolled and tested on programmed death-ligand 1 (PD-L1) expression using available tissue. We analyzed their clinical features, PD-L1 status, responses to ICIs, and overall survival (OS).We studied 93 patients with a median age 66.0 years, 23.7% of whom were women, and 22.6% were never-smokers. The results showed that G12C (36.6%) was the most common KRASm. In 47 patients with available tissue for PD-L1 testing, PD-L1 expression was positive in 66.0% of patients, while PD-L1 ≥50% was higher in ever-smokers (P = .038). Among 23 patients receiving ICI treatment, those with PD-L1 ≥50% experience a 45.5% response rate to ICI. There were benefits from ICI treatment on OS compared with no ICI treatment (median OS 35.6 vs 9.8 months, P = .002) for all of our patients, and for patients with PD-L1 ≥50% (median OS not-reached vs 8.4 months, P = .008). There were no differences in survival across different KRAS subtypes (P = .666).Never-smokers composed more than one-fifth of KRASm in NSCLC in Taiwan. A high PD-L1 expression was related to smoking history and responded well to ICI. ICI treatment improved the OS in NSCLC patients with KRASm, particularly those with PD-L1 ≥50%.  相似文献   
92.
93.
Correction for ‘Discovery of 8-prenylnaringenin from hop (Humulus lupulus L.) as a potent monoacylglycerol lipase inhibitor for treatments of neuroinflammation and Alzheimer’s disease’ by Min-Che Tung et al., RSC Adv., 2021, 11, 31062–31072, https://doi.org/10.1039/D1RA05311F.

The authors regret that the name of one of the authors (Hsing-Mien Hsu) was shown incorrectly in the original article. The corrected author list is as shown above.The authors also regret an incorrect version of Fig. 7 was included in the original article. The correct version of Fig. 7 is presented below.Open in a separate windowFig. 7The dose-dependent inhibitions of the identified inhibitors against hMAGL.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.  相似文献   
94.
To investigate the prevalence and clinical features of hepatitis D virus infection (HDV) in childhood, total antibody to hepatitis D antigen (anti-HD) in serum samples from 247 children (29 with acute hepatitis B, 68 with chronic hepatitis B, and 150 with asymptomatic hepatitis B surface antigen (HBsAg) carriers with normal liver function profiles) were studied using solid-phase competitive radioimmunoassay. Anti-HD was detected in three of the 29 children with acute hepatitis B and in only one of the 68 with chronic hepatitis B; none of the serum specimens from 150 asymptomatic carriers with normal liver function profile showed detectable anti-HD. All three children with HDV coinfection cleared HBsAg and seroconverted to anti-HBs, whereas one with superinfection finally had normal liver function without clearance of HBsAg. To identify possible sources of HDV infection, HBV markers and anti-HD in family members were also examined. One 4-month-old infant boy became infected through a blood transfusion from his hepatitis B e antigen (HBeAg)-positive carrier father, who had anti-HD. A 4-month-old infant girl was infected through close contact with her HBeAg-negative carrier father, who had HDV superinfection. The infection sources remained undefined in another two patients. The mothers of these four children were seronegative for anti-HD, indicating that perinatal transmission is not the usual mode of HDV infection in Taiwan. The natural course of either acute or chronic HBV infections in childhood in Taiwan may be more closely related to HBV itself, or to some other yet unrecognized factor, rather than to HDV infection.  相似文献   
95.
96.
STUDY OBJECTIVE: To estimate whether laparoscopic in situ morcellation (LISM) can facilitate laparoscopic-assisted vaginal hysterectomy (LAVH) for large uteri. DESIGN: Prospective study (Canadian Task Force classification II-1). SETTING: University-affiliated hospital. PATIENTS: In all, 147 women with myoma or adenomyosis weighing more than 500 g from January 2004 through December 2007 were enrolled. The patients were divided into 4 subgroups: patients with uteri weighing 500 to 749 g who had traditional LAVH without LISM (group 1A, n = 69) or with LISM (group 1B, n = 16); and patients with uteri weighing 750 g or more who were treated by traditional LAVH without LISM (group 2A, n = 38) or with LISM (group 2B, n = 24). INTERVENTIONS: Laparoscopic-assisted vaginal hysterectomy with or without LISM. MEASUREMENT AND MAIN RESULTS: No significant differences existed in age, body mass index, preoperative diagnoses, complications, or duration of hospital stay among groups. The mean uterine weights were 608 +/- 75, 597 +/- 66, 989 +/- 179, and 935 +/- 226 g for groups 1A, 1B, 2A, and 2B, respectively. The operative time (120 +/- 16 vs 157 +/- 36 minutes, p <.001; 140 +/- 19 vs 224 +/- 57 minutes, p <.001) were significantly shorter in patients with LISM than without in both groups 1 and 2. The estimated blood loss was highest in group 2A. Six (16%) patients lost more than 500 mL of blood and 3 (8%) of them needed blood transfusions. Conversion to laparotomy occurred in 1 (2.6%) of 38 patients in group 2A. No repeated surgery or surgical mortality occurred. CONCLUSION: Laparoscopic-assisted vaginal hysterectomy with LISM was an efficient and safe procedure for removal of large uteri during LAVH.  相似文献   
97.
Ectodomain shedding of epidermal growth factor receptor ligands such as transforming growth factor- alpha (TGF-alpha), heparin-binding epidermal growth factor-like growth factor (HBEGF), and amphiregulin (AREG) is considered to be important during implantation. Tumor necrosis factor-alpha converting enzyme (TACE) has been suggested as the major sheddase for these molecules. The objectives of this study are (1) to characterize the expression of TACE in the human placenta throughout gestation; (2) to determine the association between the expression of TACE with TGF-alpha, HBEGF, and AREG; (3) to ascertain whether TACE mediates TGF-alpha, HBEGF, and AREG shedding; and (4) to examine the effect of hypoxia on the expression of TACE. By analyzing a total of 55 villous samples representing different gestational ages, the authors found that TACE was continuously expressed in the placentas throughout gestation and that the levels of TACE were positively correlated with the levels of TGF-alpha, HBEGF, and AREG. Preadministration of a TACE inhibitor in villous explant cultures or transfection of cytotrophoblastic cells with TACE-specific small interference RNA decreased the shedding of HBEGF and AREG. Moreover, hypoxia (2% O(2)) caused an increase in the levels of TACE mRNA and protein in villous explants and primary cytotrophoblastic cells in vitro. These results indicate that oxygen regulates the expression of TACE and that TACE may be important for placental development during human pregnancy.  相似文献   
98.
Baicalin is a flavonoid present in many traditional Chinese medicines. A number of studies show that baicalin has anti-inflammatory actions and protects against a variety of tissue and organ injuries. The effect of baicalin in lipopolysaccharide (LPS)-induced acute lung injury is not well studied. In this study, typically acute lung injury was induced in rat by intratracheal injection of LPS, which increased lactate dehydrogenase activity and protein content in bronchoalveolar lavage fluid, wet/dry lung weight ratio, Evan's blue dye leakage, and neutrophil infiltration. Baicalin (20 mg/kg) was administrated 1 hour before or 30 min after LPS injection. Both pre and post-treatment with baicalin attenuated the increase of these parameters and improved histological finding. Our results suggest that baicalin has a therapeutic effect on LPS-induced acute lung injury.  相似文献   
99.
100.
Upper gastrointestinal bleeding from primary aortoduodenal fistula (PADF) is unusual and fatal. The etiology of PADF from tuberculous aortitis is rare. We report a 69-year-old male patient who suffered recurrent hematemesis and hematochezia with hypovolemic shock of unknown origin. Initial endoscopy failed to lead to a diagnosis. A bleeder over the third portion of the duodenum was found after the third endoscopy. Exploratory laparotomy showed a ruptured aortic pseudoaneurysm with an aortoduodenal fistula. Dacron graft repair of the aorta and simple closure of the duodenal fistula were carried out. Pathologic examination revealed tuberculous aortitis. The patient survived and was symptom-free following operation and antituberculous therapy. Review of the literature revealed that the clinical presentations in this disorder are insidious. The endoscopic findings are atypical. We conclude that so-called "herald bleeding", a history of tuberculous infection or aortic aneurysm and a high degree of suspicion are critical for successful diagnosis. Early diagnosis and surgical exploration are needed for timely and successful management.  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