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   178938篇
  免费   1218篇
  国内免费   203篇
耳鼻咽喉   1183篇
儿科学   6663篇
妇产科学   3043篇
基础医学   16921篇
口腔科学   1704篇
临床医学   12717篇
内科学   31229篇
皮肤病学   699篇
神经病学   16564篇
特种医学   9097篇
外国民族医学   1篇
外科学   29256篇
综合类   2932篇
现状与发展   3篇
一般理论   1篇
预防医学   18271篇
眼科学   2808篇
药学   9828篇
  1篇
中国医学   928篇
肿瘤学   16510篇
  2023年   74篇
  2022年   83篇
  2021年   175篇
  2020年   145篇
  2019年   176篇
  2018年   22081篇
  2017年   17479篇
  2016年   19618篇
  2015年   1055篇
  2014年   1007篇
  2013年   936篇
  2012年   7227篇
  2011年   21289篇
  2010年   18962篇
  2009年   11632篇
  2008年   19625篇
  2007年   21858篇
  2006年   664篇
  2005年   2304篇
  2004年   3433篇
  2003年   4410篇
  2002年   2545篇
  2001年   371篇
  2000年   523篇
  1999年   264篇
  1998年   258篇
  1997年   262篇
  1996年   121篇
  1995年   147篇
  1994年   128篇
  1993年   98篇
  1992年   92篇
  1991年   127篇
  1990年   161篇
  1989年   112篇
  1988年   87篇
  1987年   70篇
  1986年   50篇
  1985年   49篇
  1984年   32篇
  1983年   29篇
  1982年   25篇
  1980年   47篇
  1974年   29篇
  1968年   24篇
  1938年   60篇
  1937年   25篇
  1934年   30篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
BackgroundTo compare the recurrence rate and outcomes of double-headed pterygia using fibrin glue versus suture closure of conjunctival autograft.MethodsAll patients with double-headed pterygia who underwent pterygia excision with conjunctival autograft from January 2012 to January 2019 in the National University Hospital of Singapore were included. Patients were divided into 2 groups depending on whether fibrin glue or sutures were used to secure the conjunctival autograft in place. All patients had a minimum of 6 months follow-up.ResultsA total (26 patients) of 22 eyes had fibrin glue, while eight eyes underwent suture closure of their conjunctival autograft. Fibrin glue group had 4.5% recurrence rate, while suture group had 37.5% recurrence rate (p = .021). There is statistically significant improvement for overall visual acuity (p = .009) and cylinder (p = .002). There is also statistically significant improvement for visual acuity in the glue group (p = .026), but not in the suture group. Fibrin glue group had a shorter operation duration time compared to suture group (p < .001).There were no cases of graft dislocation, contraction or limbal stem cell deficiency.ConclusionsLow recurrence rates and good postoperative visual outcomes can be achieved with the split conjunctival autograft technique. Our study suggests that fibrin glue has an additional benefit over the use of sutures in the management of these complex cases.  相似文献   
3.
4.
Identification of deleterious variants in hereditary breast and ovarian cancer (HBOC) susceptibility genes allows for increased clinical surveillance and early detection, and could predict the response to poly (ADP‐ribose) polymerase (PARP) inhibitor in patients with advanced ovarian carcinomas. To determine the prevalence and clinical prediction factors for HBOC syndrome, 882 selected individuals underwent multigene panel testing for HBOC risk assessment during the period from January 2015 to March 2018. Overall, 176 deleterious mutations were observed in 19.50% (n = 172) of individuals. Twenty‐six of 176 mutations could not be retrieved in related public databases and were considered to be novel. Among patients with ovarian cancer, 115 deleterious mutations were identified in 429 patients (48.6%) with significant enrichment for a family history of breast or ovarian cancer syndrome (P < .05). In the breast cancer subgroup, 31 deleterious mutations were identified in 261 patients. Besides BRCA1 (8; 25.8%) and BRCA2 (11; 35.5%), the most frequently occurring genes, an additional 12 deleterious mutations (38.7%) were found in seven other susceptibility genes. Higher mutation incidence (57.9%) was observed in subjects with histories of breast and ovarian cancer. Our results highlighted the genetic heterogeneity of HBOC and the efficiency of a multigene panel in carrying out risk assessment.  相似文献   
5.
1. Corydaline, an isoquinoline alkaloid obtained from the rhizomes of Corydalis yanhusuo, exhibits anti-acetylcholinesterase, anti-angiogenic, anti-allergic and gastric-emptying activities. In this study, a rapid and reliable ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) method was developed and employed for the comprehensive study of the metabolites of corydaline in rats.

2. Altogether, 43 metabolites were identified in the plasma (11), bile (9), urine (34) and feces (21) of rats after oral administration of corydaline at a dose of 4.5mg/kg.

3. It was demonstrated that demethylation, hydroxylation, sulfation and glucuronidation were the major metabolic transformation pathways. Among these, two metabolites were identified as tetrahydropalmatine and isocorybulbine, and 33 phase I and phase II products were inferred to be new metabolites arising from the in vivo metabolism of corydaline.

4. Importantly, this research provides scientific and reliable support for full understanding of the metabolic profiles of corydaline and the results could help to elucidate its safety and efficacy.  相似文献   

6.
目的 运用网络药理学探讨“黄芪-当归-大枣”角药补气养血的分子机制。方法 利用中药系统药理学TCMSP数据库收集黄芪、当归和大枣的化学成分,并预测作用靶点。通过STRING数据库和Cytoscape软件构建蛋白互作PPI网络,获得关键靶点。借助DAVID数据库对筛选靶点进行GO功能和KEGG通路富集分析。进一步构建气血两虚小鼠模型,灌胃“黄芪-当归-大枣”水煎剂,检测各组PTGS2 mRNA表达水平与肿瘤坏死因子-α(TNF-α)含量,完成验证实验。结果 筛选得到“黄芪-当归-大枣”角药化学成分47个,预测作用靶点43个,关键靶点10个,生物功能主要定位在内质网膜和线粒体,通过介导癌症信号通路,TNF、P53、Foxo、HIF-1信号通路,钙信号通路等发挥补气养血作用。动物实验显示“黄芪-当归-大枣”角药可调控气血两虚小鼠中PTGS2 mRNA表达,降低TNF-α释放,进而抑制TNF信号通路的激活,进一步证实了预测的可靠性。结论 本研究深入诠释“黄芪-当归-大枣”角药补气养血作用多成分、多靶点和多通路的复杂机制,为其进一步临床应用和功能食品开发提供科学依据。  相似文献   
7.
Recent research indicates that marijuana-infused food product (i.e., edible) use is becoming nearly as common as smoking marijuana where medical marijuana is available. This study explores edible use among teens. We conducted four focus groups in the San Francisco Bay Area with youth, ages 15–17. The focus groups were divided by gender and whether they used marijuana. Some teens mentioned edible use at school. Youth reported that teens consume edibles, primarily to reduce the likelihood of getting caught. Edibles are also attractive to those who do not like to smoke or have concerns about smoking. Both male and female respondents suggested that females are more likely than males to prefer edibles over smoking, one reason for which may be to avoid smelling like marijuana smoke. For some young women, edibles may be a way to avoid publicly presenting themselves as marijuana users. Findings also suggest that youth have access to edibles through multiple sources. Youth reported that they can purchase edibles at school from other students who either make the edibles themselves or are reselling edibles obtained from dispensaries. Both users and non-users were aware of potentially negative consequences related to edible use. Some youth mentioned that they have heard of youth dying from edibles, and several reported being concerned about the high produced by edibles. Female non-users appeared to be more concerned than others about edibles and compared them to drinks that could be spiked with drugs. However, sentiment among some male marijuana users was that if you cannot handle edibles you should not be using them. These findings suggest that strategies to curb access to edibles and use among youth, such as restricting sales of edibles with strong youth appeal and educating youth on the risks of edibles, will need to be developed.  相似文献   
8.
Providing assistance services for sexual activity is becoming of increasing importance to the community of people with disabilities and to mental health professionals. Nevertheless, the literature on this topic is sparse. The aim of this study is to explore potential clients’ and assistants’ views, needs, experiences, opinions, and concerns about sexual assistance (SA) in Italy. Twenty-two semi-structured interviews were conducted with 12 people with a congenital physical disability and 10 would-be assistants. A Grounded Theory approach was used to analyze data. Participants with disabilities considered SA useful. Despite most of them having unfulfilled sexual needs, they would prefer to have their sexual needs met within a romantic relationship. Would-be assistants constructed themselves as people who have a “natural aptitude to being useful”. Results suggest that SA services might represent an opportunity for people with disabilities to discover new ways to satisfy their personal needs and to live more autonomously while, at the same time, allowing would-be sexual assistants to fulfill their desire to be helpful. Nevertheless, the use of SA is likely to only be a part of the answer to fulfilling the sexual needs of people with disabilities.  相似文献   
9.
Social media has become a major platform for debates on science and health. This commentary argues that while social media can present challenges to communicating important health matters, it can also provide health experts a unique opportunity to engage with and build trust among members of the public.  相似文献   
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