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   60352篇
  免费   2962篇
  国内免费   453篇
耳鼻咽喉   528篇
儿科学   1178篇
妇产科学   699篇
基础医学   8028篇
口腔科学   1232篇
临床医学   3735篇
内科学   15058篇
皮肤病学   1271篇
神经病学   4758篇
特种医学   2675篇
外科学   11130篇
综合类   222篇
一般理论   6篇
预防医学   1518篇
眼科学   1336篇
药学   4049篇
中国医学   208篇
肿瘤学   6136篇
  2023年   266篇
  2022年   207篇
  2021年   1044篇
  2020年   606篇
  2019年   870篇
  2018年   1230篇
  2017年   919篇
  2016年   1145篇
  2015年   1219篇
  2014年   1621篇
  2013年   2053篇
  2012年   3276篇
  2011年   3670篇
  2010年   2039篇
  2009年   1865篇
  2008年   3346篇
  2007年   3692篇
  2006年   3746篇
  2005年   3714篇
  2004年   3788篇
  2003年   3806篇
  2002年   3761篇
  2001年   1195篇
  2000年   1139篇
  1999年   1210篇
  1998年   868篇
  1997年   731篇
  1996年   667篇
  1995年   622篇
  1994年   573篇
  1993年   615篇
  1992年   807篇
  1991年   744篇
  1990年   657篇
  1989年   634篇
  1988年   634篇
  1987年   523篇
  1986年   487篇
  1985年   494篇
  1984年   349篇
  1983年   279篇
  1982年   202篇
  1981年   227篇
  1980年   195篇
  1979年   249篇
  1978年   221篇
  1977年   165篇
  1976年   140篇
  1974年   161篇
  1973年   148篇
排序方式: 共有10000条查询结果,搜索用时 578 毫秒
1.
BackgroundIn shoulder arthroplasty, bone resorption around the stem can lead to stem loosening and makes surgery difficult at the time of revision. Proximal bone resorption after reverse shoulder arthroplasty can cause instability because of a decrease of deltoid wrapping effect. As factors of the stem itself, such as stem coating, shape, length, and use of bone cement, may also affect bone resorption, a single-stem model should be used to compare bone resorptions between different pathologies and surgical procedures. However, to date, a few reports have compared these differences in detail using a single-stem model. Therefore, we investigated the prevalence and location of humeral bone resorption in a single-stem model.MethodsThe study included 100 shoulders that underwent anatomical total shoulder arthroplasty (TSA) or humeral head replacement (HHR) with a single uncemented humeral stem from 2008 to 2018. The patients were 31 men and 69 women. The mean age at surgery was 72.9 years (range, 41-86 years). The patients were divided into three groups: especially, 25, 61, and 14 shoulders received TSA for primary osteoarthritis without rotator cuff tears (TSA group), HHR using an anatomical head with rotator cuff repair for cuff tear arthropathy (CTA) (HHR group), and HHR using a CTA head without rotator cuff repair (CTA group), respectively. Patients were monitored for a mean of 56 months (range, 12-98 months). The location of bone resorption was divided into seven zones as follows: zone 1, greater tuberosity; zone 2, lateral diaphysis; zone 3, lateral diaphysis beyond the deltoid tuberosity; zone 4, tip of the stem; zone 5, medial diaphysis beyond the deltoid tuberosity; zone 6, medial diaphysis; and zone 7, calcar region. The degree of bone resorption was classified from grade 0 to 4.ResultsBone resorption of grade 3 or higher was significantly more frequent at the greater tuberosity in the HHR and CTA groups (P < .001 and P < .001, respectively) than that in the TSA group. Grade 4 bone resorption was significantly more frequent in the CTA than that in the TSA and HHR groups in zone 1 (P = .016 and P = .041, respectively).ConclusionThe state of attachment of the rotator cuff to the greater tuberosity might affect bone resorption at the greater tuberosity, such as the greater tuberosity after shoulder arthroplasty. In cases of shoulder arthroplasty for arthropathy with rotator cuff tear, performing rotator cuff repair might prevent bone resorption.Level of evidenceLevel IV; Prognosis Study  相似文献   
2.
3.
4.
To obtain baseline data for cervical cancer prevention in Japan, we analyzed human papillomavirus (HPV) data from 5045 Japanese women aged less than 40 years and diagnosed with cervical abnormalities at 21 hospitals during 2012‐2017. These included cervical intraepithelial neoplasia grade 1 (CIN1, n = 573), CIN2‐3 (n = 3219), adenocarcinoma in situ (AIS, n = 123), and invasive cervical cancer (ICC, n = 1130). The Roche Linear Array was used for HPV genotyping. The HPV type‐specific relative contributions (RCs) were estimated by adding multiple infections to single types in accordance with proportional weighting attributions. Based on the comparison of type‐specific RCs between CIN1 and CIN2‐3/AIS/ICC (CIN2+), RC ratios were calculated to estimate type‐specific risks for progression to CIN2+. Human papillomavirus DNA was detected in 85.5% of CIN1, 95.7% of CIN2‐3/AIS, and 91.2% of ICC. Multiple infections decreased with disease severity: 42.9% in CIN1, 40.4% in CIN2‐3/AIS, and 23.7% in ICC (P < .0001). The relative risk for progression to CIN2+ was highest for HPV16 (RC ratio 3.78, 95% confidence interval [CI] 3.01‐4.98), followed by HPV31 (2.51, 1.54‐5.24), HPV18 (2.43, 1.59‐4.32), HPV35 (1.56, 0.43‐8.36), HPV33 (1.01, 0.49‐3.31), HPV52 (0.99, 0.76‐1.33), and HPV58 (0.97, 0.75‐1.32). The relative risk of disease progression was 1.87 (95% CI, 1.71‐2.05) for HPV16/18/31/33/35/45/52/58, but only 0.17 (95% CI, 0.14‐0.22) for HPV39/51/56/59/66/68. Human papillomavirus 16/18/31/33/45/52/58/6/11 included in a 9‐valent vaccine contributed to 89.7% (95% CI, 88.7‐90.7) of CIN2‐3/AIS and 93.8% (95% CI, 92.4‐95.3) of ICC. In conclusion, our data support the Japanese guidelines that recommend discriminating HPV16/18/31/33/35/45/52/58 genotypes for CIN management. The 9‐valent vaccine is estimated to provide over 90% protection against ICC in young Japanese women.  相似文献   
5.
Cancer stem cells (CSCs) play a decisive role in the development and progression of cancer. To investigate CSCs in Epstein‐Barr virus (EBV)‐associated carcinoma (EBVaGC), we screened previously reported stem cell markers of gastric cancer in EBV‐infected gastric cancer cell lines (TMK1 and NUGC3) and identified CD44v6v9 double positive cells as candidate CSCs. CD44v6/v9+/+ cells were sorted from EBVaGC cell line (SNU719) cells and EBV‐infected TMK1 cells and these cell populations showed high spheroid‐forming ability and tumor formation in SCID mice compared with the respective CD44v6/v9?/? cells. Sphere‐forming ability was dependent on the nuclear factor‐κB (NF‐κB) signaling pathway, which was confirmed by decrease of sphere formation ability under BAY 11‐7082. Small interfering RNA knockdown of latent membrane protein 2A (LMP2A), one of the latent gene products of EBV infection, decreased spheroid formation in SNU719 cells. Transfection of the LMP2A gene increased the sphere‐forming ability of TMK1 cells, which was mediated through NF‐κB signaling. Together, these results indicate that CD44v6v9+/+ cells are CSCs in EBVaGC that are maintained through the LMP2A/NF‐κB pathway. Future studies should investigate CD44v6/v9+/+ cells in normal and neoplastic gastric epithelium to prevent and treat this specific subtype of gastric cancer infected with EBV.  相似文献   
6.
7.
Objectives: Phase angle (PA) is a poor prognostic factor in patients with advanced cancer. This study aimed to identify possible correlations between PA and symptoms, quality of life, fluid retention, and laboratory data in cancer patients in palliative care settings.

Methods: Individuals who visited the outpatient clinic or were admitted to the palliative care unit were eligible. Patients with a performance status of 4 and/or those unable to complete questionnaires were excluded. PA was evaluated using a bioanalyzer device. The correlation coefficient between PA and the variables of interest was analyzed.

Results: A total of 102 patients were analyzed. PA was weakly correlated with age (ρ = ?0.22), performance status (ρ = ?0.30), functional well-being (ρ?=?0.20), anorexia/cachexia subscale (ρ?=?0.22), and Functional Assessment of Anorexia/Cachexia Therapy trial outcome index (ρ?=?0.26). PA was also correlated with fluid retention (ρ = ?0.34) and albumin (ρ?=?0.32), C-reactive protein (ρ = ?0.31), and hemoglobin (ρ?=?0.41) levels. Sub-analysis stratified according to sex revealed that males demonstrated the same results; however, female sex demonstrated a correlation between PA and social well-being (ρ = ?0.43).

Conclusions: PA was correlated with physical condition, but not with psychological well-being.  相似文献   

8.
9.
10.
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