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   28921篇
  免费   1560篇
  国内免费   131篇
耳鼻咽喉   272篇
儿科学   561篇
妇产科学   449篇
基础医学   3609篇
口腔科学   894篇
临床医学   1986篇
内科学   7145篇
皮肤病学   503篇
神经病学   2420篇
特种医学   1417篇
外科学   4603篇
综合类   111篇
一般理论   1篇
预防医学   759篇
眼科学   525篇
药学   2141篇
中国医学   65篇
肿瘤学   3151篇
  2023年   148篇
  2022年   117篇
  2021年   536篇
  2020年   320篇
  2019年   474篇
  2018年   555篇
  2017年   446篇
  2016年   535篇
  2015年   549篇
  2014年   749篇
  2013年   914篇
  2012年   1424篇
  2011年   1599篇
  2010年   820篇
  2009年   739篇
  2008年   1347篇
  2007年   1401篇
  2006年   1367篇
  2005年   1414篇
  2004年   1295篇
  2003年   1328篇
  2002年   1336篇
  2001年   961篇
  2000年   972篇
  1999年   969篇
  1998年   354篇
  1997年   271篇
  1996年   250篇
  1995年   251篇
  1994年   206篇
  1993年   206篇
  1992年   688篇
  1991年   593篇
  1990年   612篇
  1989年   599篇
  1988年   512篇
  1987年   463篇
  1986年   457篇
  1985年   412篇
  1984年   287篇
  1983年   244篇
  1980年   101篇
  1979年   249篇
  1978年   145篇
  1977年   132篇
  1975年   102篇
  1974年   98篇
  1972年   105篇
  1971年   103篇
  1969年   101篇
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
1.
ARID1A, one of the subunits in SWI/SNF chromatin remodeling complex, is frequently mutated in gastric cancers with microsatellite instability (MSI). The most frequent MSI in solid‐type poorly differentiated adenocarcinoma (PDA) has been reported, but the SWI/SNF complex status in solid‐type PDA is still largely unknown. We retrospectively analyzed 54 cases of solid‐type PDA for the expressions of mismatch repair (MMR) proteins (MLH1, PMS2, MSH2, and MSH6), SWI/SNF complex subunits (ARID1A, INI1, BRG1, BRM, BAF155, and BAF170) and EBER, and mutations in KRAS and BRAF. We analyzed 40 cases of another histological type of gastric cancer as a control group. The solid‐type PDAs showed coexisting glandular components (76%), MMR deficiency (39%), and complete/partial loss of ARID1A (31%/7%), INI1 (4%/4%), BRG1 (48%/30%), BRM (33%/33%), BAF155 (13%/41%), and BAF170 (6%/2%), EBER positivity (4%), KRAS mutation (2%), and BRAF mutation (2%). Compared to the control group, MMR deficiency and losses of ARID1A, BRG1, BRM, and BAF155 were significantly frequent in solid‐type PDAs. Mismatch repair deficiency was associated with the losses of ARID1A, BRG1, and BAF155 in solid‐type PDAs. In the MMR‐deficient group, solid components showed significantly more frequent losses of ARID1A, BRG1, BRM, and BAF155 compared to glandular components (P = .0268, P = .0181, P = .0224, and P = .0071, respectively). In the MMR‐proficient group, solid components showed significantly more frequent loss of BRG1 compared to glandular components (P = .012). In conclusion, solid‐type PDAs showed frequent losses of MMR proteins and the SWI/SNF complex. We suggest that loss of the SWI/SNF complex could induce a morphological shift from differentiated‐type adenocarcinoma to solid‐type PDA.  相似文献   
2.

Background

Mental health is a major public health priority, particularly among refugees worldwide. The United Nations Relief and Works Agency for Palestine Refugees (UNRWA) started to integrate mental health and psychosocial support (MHPSS) into its primary health-care services in Jordan in late 2017. This baseline study aimed to assess the knowledge, attitudes, practices, and perceived barriers among UNRWA health staff regarding the implementation of the MHPSS programme.

Methods

The UNRWA Health Programme conducted a cross-sectional study of a sample of 220 out of the 390 male and female doctors, dentists, nurses, and midwives who work at 16 of the 25 UNRWA health centres in Jordan during November, 2017. Individuals on duty at the health centres on the day of the survey were included. The 16 health centres were selected based on their size and accessibility to surveyors (reflecting proximity to Amman, and the size of population served). Of the selected health centres, seven were large, seven were medium, and two were small according to the UNRWA classification of health centres (based on the number of medical doctors). A validated self-administered questionnaire was used. Ethics approval was granted by the UNRWA Health Programme ethics committee, and informed written consent was obtained from all participants. Data analysis was performed using SPSS (version 22).

Findings

Of the participants, 73% (161 of 220) believed that their knowledge of MHPSS programmes was insufficient, with no significant difference (p=0·116) between different categories of staff. Furthermore, 88% (194 of 220) said that they needed more training, 67% (147 of 220) reported that the number of mental health cases is increasing, and 50% (110 of 220) that dealing with these cases is difficult. Reflecting on the past 12 months, 31% of staff (69 out of 220) reported meeting between one and ten children, and 45% (100 out of 220) reported meeting between one and ten adults suspected of having mental illnesses. The most suspected condition was depression (84%; 150 of 220), followed by epilepsy (64%; 140 of 220). The main perceived barriers to implementation included the limited availability of MHPSS policies (87%; 192 of 220), MH professionals (86%; 190 of 220), resources (86%; 189 out of 220), and lack of privacy (14%; 31 out of 220).

Interpretation

Most health staff had positive attitudes towards MHPSS programme implementation but felt they lacked the required knowledge. There is a need for training and clear technical guidelines. Perceived barriers to MHPSS programme implementation need to be tackled with a structured plan of action.

Funding

The UNRWA Health Programme, UNRWA Headquarters, Amman, Jordan.  相似文献   
3.
4.
BackgroundMalnutrition measured by the geriatric nutritional risk index (GNRI) was reported to be associated with poor prognosis for patients with peripheral artery disease (PAD). However, the optimal cut-off value of preprocedural GNRI for critical limb ischemia (CLI) and intermittent claudication (IC) is unknown. We aimed to determine its optimal cut-off value for CLI or IC patients requiring endovascular revascularization.MethodsWe explored data of 2246 patients (CLI: n = 1061, IC: n = 1185) registered in the Tokyo-taMA peripheral vascular intervention research COmraDE (TOMA-CODE) registry, which prospectively enrolled consecutive PAD patients who underwent endovascular revascularization in 34 hospitals in Japan from August 2014 to August 2016. The optimal cut-off values of GNRI were assessed by the survival classification and regression tree (CART) analyses, and the survival curve analyses for major adverse cardiovascular and limb events (MACLEs) were performed for these cut-off values.ResultsIn addition to the first cut-off value of 96.2 in CLI and 85.6 in IC, the survival CART provided an additional cut-off value of 78.2 in CLI and 106.0 in IC for further risk stratification. The survival curve was significantly stratified by the GNRI-based malnutrition status in both CLI [high risk: 47.7% (51/107), moderate: 30.1% (118/392), and low: 10.2% (53/520), log–rank p < 0.001] and IC [high risk: 14.3% (7/49), moderate: 4.5% (29/646), and low: 0.5% (2/407), log–rank p < 0.001]. The multivariate Cox-proportional hazard analysis showed that a higher GNRI was significantly associated with a better outcome in both CLI [hazard ratio (HR) per 1-point increase: 0.97, 95% CI: 0.96–0.98, p < 0.001] and IC (HR: 0.94, 95% CI: 0.91–0.97, p < 0.001).ConclusionsPreprocedural nutritional status significantly stratified future events in patients with PAD. Given that the optimal cut-off value of GNRI in CLI was almost 10-points lower than that of IC, using a disease-specific cut-off value is important for risk stratification.  相似文献   
5.
6.
7.
8.

Background

Controversy continues as to whether single-incision laparoscopic cholecystectomy, with the somewhat larger incision at the umbilicus, may lead to a worse postoperative quality of life and more pain compared with the more classic 4-port laparoscopic cholecystectomy. The aim of this study was to compare single-incision and 4-port laparoscopic cholecystectomy from the perspective of quality of life.

Methods

This study was a multicenter, parallel-group, open-label, randomized clinical trial. A total of 120 patients who were scheduled to undergo elective cholecystectomy were randomly assigned 1:1 into the single-incision laparoscopic cholecystectomy or the 4-port laparoscopic cholecystectomy group and then assessed continuously for 2 weeks during the postoperative period. The primary outcome was quality of life, defined as the time to resume normal daily activities. Postoperative pain was also assessed. To explore the heterogeneity of treatment effects, we assessed the interactions of sex, age, and working status on recovery time.

Results

A total of 58 patients in the single-incision group and 53 in the 4-port group (n?=?111, 47 male, mean age 57 years) were analyzed. The mean time to resume daily activities was 10.2 days and 8.8 days, respectively, for single-incision and 4-port laparoscopic cholecystectomy (95% confidence interval –0.4 to 3.2, P?=?.12). Similarly, the time to relief from postoperative pain did not differ significantly between the groups. Statistically insignificant but qualitative interactions were noted; in the subgroups of women, full-time workers, and patients younger than 60 years, recovery tended to be slower after single-incision laparoscopic cholecystectomy.

Conclusion

Postoperative quality of life did not differ substantially between single-incision laparoscopic cholecystectomy and 4-port laparoscopic cholecystectomy. Patients younger than 60 years, women, and full-time workers tended to have a somewhat slower recovery after single-incision laparoscopic cholecystectomy.  相似文献   
9.
10.
The interaction of CD47 and signal-regulatory protein alpha (SIRPα) induces “don't eat me signal”, leading suppression of phagocytosis. This signal can affect the clinical course of malignant disease. Although CD47 and SIRPα expression are associated with clinicopathological features in several neoplasms, the investigation for adult T-cell leukemia/lymphoma (ATLL) has not been well-documented. This study aimed to declare the association between CD47 and SIRPα expression and clinicopathological features in ATLL. We performed immunostaining on 73 biopsy samples and found that CD47 is primarily expressed in tumor cells, while SIRPα is expressed in non-neoplastic stromal cells. CD47 positive cases showed significantly higher FoxP3 (P = .0232) and lower CCR4 (P = .0214). SIRPα positive cases presented significantly better overall survival than SIRPα negative cases (P = .0132). SIRPα positive cases showed significantly HLA class I (P = .0062), HLA class II (P = .0133), microenvironment PD-L1 (miPD-L1) (P = .0032), and FoxP3 (P = .0229) positivity. In univariate analysis, SIRPα expression was significantly related to prognosis (Hazard ratio [HR] 0.470; 95% confidence interval [CI] 0.253-0.870; P = .0167], although multivariate analysis did not show SIPRα as an independent prognostic factor. The expression of SIRPα on stromal cells reflects activated immune surveillance mechanism in tumor microenvironment and induce good prognosis in ATLL. More detailed studies for gene expression or genomic abnormalities will disclose clinical and biological significance of the CD47 and SIRPα in ATLL.  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