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   37389篇
  免费   2094篇
  国内免费   110篇
耳鼻咽喉   346篇
儿科学   1011篇
妇产科学   919篇
基础医学   6239篇
口腔科学   672篇
临床医学   4346篇
内科学   5851篇
皮肤病学   849篇
神经病学   3630篇
特种医学   2179篇
外科学   3647篇
综合类   218篇
一般理论   26篇
预防医学   3819篇
眼科学   550篇
药学   3030篇
  1篇
中国医学   150篇
肿瘤学   2110篇
  2023年   256篇
  2022年   420篇
  2021年   788篇
  2020年   532篇
  2019年   727篇
  2018年   1023篇
  2017年   713篇
  2016年   843篇
  2015年   954篇
  2014年   1193篇
  2013年   1955篇
  2012年   2743篇
  2011年   3211篇
  2010年   1654篇
  2009年   1237篇
  2008年   2520篇
  2007年   2754篇
  2006年   2691篇
  2005年   2374篇
  2004年   2211篇
  2003年   2081篇
  2002年   1827篇
  2001年   553篇
  2000年   629篇
  1999年   448篇
  1998年   322篇
  1997年   230篇
  1996年   210篇
  1995年   172篇
  1994年   157篇
  1993年   137篇
  1992年   102篇
  1991年   116篇
  1990年   111篇
  1989年   110篇
  1988年   77篇
  1987年   64篇
  1986年   75篇
  1985年   83篇
  1984年   97篇
  1983年   98篇
  1982年   107篇
  1981年   88篇
  1980年   85篇
  1979年   74篇
  1978年   53篇
  1977年   47篇
  1976年   53篇
  1975年   54篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
Breast pseudoaneurysms after a core needle biopsy are a rare complication with a low incidence. However, it is important to be aware of the possibility of complications that require treatment.  相似文献   
3.
4.
ABSTRACT

Although communication about sexuality is a significant pathway through which peers influence adolescent sexual development, little research has examined the role of peer networks in the use of sexualized media. We applied a social network approach to assess the role of close peers in adolescent pornography use and sexting in a sample of Croatian high school students. Sexual conversation networks’ characteristics did not correlate with pornography use. In contrast, sexting was associated with the proportion of same gender peers, the proportion of older peers and the proportion of sexually experienced peers in the network – pointing to the role of peer influence. Participants’ gender did not moderate these associations. Specific mechanisms underlying the observed associations and the role of peer selection remain important tasks for future research.  相似文献   
5.
Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs.  相似文献   
6.
7.

Objectives

To determine the incidence of incisional hernia (IH) in the extraction incision (EI) in colorectal resection for cancer. To analyze whether the location of the incision has any relationship with the incidence of hernias and whether mesh could be useful for prevention in high-risk patients.

Methods

Retrospective review of the colon and rectal surgery database from January 2015 to December 2016. Data were classified into 2 groups, transverse (TI) and midline incision (MI), and the latter was divided into 2 subgroups (mesh [MIM] and suture [MIS]). Patients were classified using the HERNIAscore. Hernias were diagnosed by clinical and/or CT examination.

Results

A total of 182 out of 210 surgical patients were included. After a median follow-up of 13.0 months, 39 IH (21.9%) were detected, 23 of which (13.4%) were in the EI; their frequency was lower in the TI group (3.4%) and in the MIM group (5.9%) than in the MIS group (29.5%; p = 0.007). The probability of developing IH in the MIS group showed an OR = 11.7 (95%CI: 3.3-42.0) compared to the TI group and 4.3 (IC 95%: 1.1-16.3) versus the MIM group.

Conclusions

The location of the incision is relevant to avoid incisional hernias. Transverse incisions should be used as the first option. When a midline incision is needed, a prophylactic mesh could be considered in high risk patients because it is safe and associated with low morbidity.  相似文献   
8.
9.
ObjectiveThe purpose of this paper is to review the efficacy and safety profile in children treated with topical 0.03% Tacrolimus ointment for vernal keratoconjunctivitis in Middle East and to propose a treatment posology. According to recent studies, a complex non-IgE dependent mechanism plays a relevant role in the pathogenesis of vernal keratoconjunctivitis. Numerous cells and mediators have been found in the serum, conjunctiva and tears of patients with Vernal keratoconjunctivitis.DesignThis case series included 10 patients from a single centre, pediatric department of a tertiary hospital with active symptomatic vernal keratoconjunctivitis. All the patients had proliferative lesions and corneal involvement despite conventional medications, including topical steroids. All other medications, systemic and topical: steroids, antihistamines and cyclosporine, were unsuccessful. Patients were treated with topical 0.03% Tacrolimus ointment twice daily for 8 weeks and then once a day for the next two month followed by thrice a week for two months. The changes in symptoms and signs after treatment were evaluated, also the development of possible complications was assessed.ResultsThe results showed a significant reduction in signs and symptoms after 4 weeks of the treatment. Clinical resolution of giant papillae and corneal lesions were seen within eight weeks and no additional drug was required during that period, except tear substitutes. Treatment was continued for period of two months and then slowly reduced.ConclusionThe use of 0.03% Tacrolimus ointment is safe and effective in children refractory to conventional treatment of vernal keratoconjunctivitis even in high temperature climate as Middle East. Due to the effectiveness of the treatment, the dosage used may be proposed for conventional use.  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