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   4491篇
  免费   235篇
  国内免费   19篇
耳鼻咽喉   23篇
儿科学   133篇
妇产科学   101篇
基础医学   546篇
口腔科学   90篇
临床医学   429篇
内科学   830篇
皮肤病学   92篇
神经病学   430篇
特种医学   122篇
外科学   535篇
综合类   19篇
一般理论   4篇
预防医学   502篇
眼科学   125篇
药学   276篇
中国医学   4篇
肿瘤学   484篇
  2024年   3篇
  2023年   45篇
  2022年   96篇
  2021年   181篇
  2020年   121篇
  2019年   149篇
  2018年   164篇
  2017年   118篇
  2016年   134篇
  2015年   142篇
  2014年   182篇
  2013年   233篇
  2012年   362篇
  2011年   353篇
  2010年   226篇
  2009年   204篇
  2008年   263篇
  2007年   314篇
  2006年   291篇
  2005年   248篇
  2004年   213篇
  2003年   223篇
  2002年   159篇
  2001年   22篇
  2000年   20篇
  1999年   16篇
  1998年   46篇
  1997年   30篇
  1996年   19篇
  1995年   20篇
  1994年   20篇
  1993年   18篇
  1992年   6篇
  1991年   10篇
  1990年   6篇
  1989年   10篇
  1988年   5篇
  1987年   8篇
  1986年   4篇
  1984年   4篇
  1983年   5篇
  1982年   14篇
  1981年   5篇
  1980年   4篇
  1979年   2篇
  1978年   6篇
  1976年   2篇
  1974年   4篇
  1973年   2篇
  1962年   2篇
排序方式: 共有4745条查询结果,搜索用时 15 毫秒
81.
Background contextVertebral artery injuries (VAIs) are rare but serious complications of cervical spine surgery, with the potential to cause catastrophic bleeding, permanent neurologic impairment, and even death. The present literature regarding incidence of this complication largely comprises a single surgeon or small multicenter case series.PurposeWe sought to gather a large sample of high-volume surgeons to adequately characterize the incidence and risk factors for VAI, management strategies used, and patient outcomes after VAI.Study designThe study was constructed as a cross-sectional study comprising all cervical spine patients operated on by the members of the international Cervical Spine Research Society (CSRS).Patient sampleAll patients who have undergone cervical spine surgery by a current member of CSRS as of the spring of 2012.Outcome measuresFor each surgeon surveyed, we collected self-reported measures to include the number of cervical cases performed in the surgeon's career, the number of VAIs encountered, the stage of the case during which the injury occurred, the management strategies used, and the overall patient outcome after injury.MethodsAn anonymous 10-question web-based survey was distributed to the members of the CSRS. Statistical analysis was performed using Student t tests for numerical outcomes and chi-squared analysis for categorical variables.ResultsOne hundred forty-one CSRS members (of 195 total, 72%) responded to the survey, accounting for a total of 163,324 cervical spine surgeries performed. The overall incidence of VAI was 0.07% (111/163,324). Posterior instrumentation of the upper cervical spine (32.4%), anterior corpectomy (23.4%), and posterior exposure of the cervical spine (11.7%) were the most common stages of the case to result in an injury to the vertebral artery. Discectomy (9%) and anterior exposure of the spine (7.2%) were also common time points for an arterial injury. One-fifth (22/111) of all VAI involved an anomalous course of the vertebral artery. The most common management of VAI was by direct tamponade. The outcomes of VAIs included no permanent sequelae in 90% of patients, permanent neurologic sequelae in 5.5%, and death in 4.5%. Surgeons at academic and private centers had nearly identical rates of VAIs. However, surgeons who had performed 300 or fewer cervical spine surgeries in their career had a VAI incidence of 0.33% compared with 0.06% in those with greater than 300 lifetime cases (p=.028).ConclusionsThe overall incidence of VAI during cervical spine surgery reported from this survey was 0.07%. Less experienced surgeons had a higher rate of VAI compared with their more experienced peers. The results of VAI are highly variable, resulting in no permanent harm most of the time; however, permanent neurologic injury or death occur in 10% of cases.  相似文献   
82.
83.
84.
85.
Nonsteroidal anti-inflammatory drugs decrease sporadic colorectal carcinoma and adenomas in patients with familial adenomatous polyposis and in rodent models of sporadic colon cancer and familial adenomatous polyposis. Similarly, selective cyclooxygenase 2 inhibitors decrease adenomas in humans and rodents. However, their effects on chronic colitis and colitis-associated neoplasia are unknown. Interleukin 10-/- mice (C57/B6) were fed regular chow (n = 20) or chow with celecoxib (1,500 ppm, n = 18) or rofecoxib (75 ppm, n = 20) for 12 weeks. Twenty-eight percent of the celecoxib group died versus 5% of the control and rofecoxib groups (p < 0.05 compared with control). Celecoxib and rofecoxib increased the incidence of colitis (26% vs. 92% and 68%, p < 0.01), colitis score (0.4 +/- 0.2 vs. 2.5 +/- 0.3 and 2 +/- 0.4, p < 0.01), aberrant crypt foci (0.5 +/- 0.3 vs. 3.7 +/- 2.6 and 2.8 +/- 0.7, p < 0.01), aberrant crypts per mouse (4.11 +/- 2.1 vs. 41.2 +/- 9.7 and 27.1 +/- 7.5, p < 0.01) and dysplasia (11% vs. 54% and 42%, p < 0.01). Similarly, indomethacin (9 ppm, n = 15) increased colitis score, aberrant crypt foci, and dysplasia after 27 days of treatment. Two selective cyclooxygenase 2 inhibitors exacerbate colitis and premalignant changes in the interleukin 10-/- mouse model of chronic colitis and colitis-associated colon carcinoma.  相似文献   
86.

Background  

Trying to confront with the widespread burden of infectious diseases, the society worldwide invests considerably on research. We evaluated the contribution of different world regions in research production in Infectious Diseases.  相似文献   
87.
Pistacia lentiscus var. Chia (Anacardiaceae) grows almost exclusively on Chios Island, Greece, and gives a resinous exudate resin used for culinary purposes by Mediterranean people. We investigated the molecular mechanisms through which total polar extract of the resin inhibits oxidized low-density lipoprotein (oxLDL) cytotoxic effect on peripheral blood mononuclear cell (PBMC). Cells exposed to oxLDL underwent apoptosis and necrosis, dependent on the duration of exposure. When culturing cells with oxLDL and the polar extract concurrently, we observed inhibition of both the phenomena. Because under oxidative stress the pro-oxidant systems outbalance the antioxidant, potentially producing oxidative damage and ultimately leading to cell death, we measured the levels of intracellular antioxidant glutathione (GSH). Additionally, we measured CD36 expression, a class B scavenger receptor, on CD14-positive cells, as CD36 has been identified as the oxLDL receptor in macrophages and may play a pivotal role in atherosclerotic foam cell formation. oxLDL decreased GSH levels and upregulated CD36 expression. P. lentiscus extract restored GSH levels and downregulated CD36 expression, even at the mRNA level. In order to find out the biologically drastic constituents of the resin's polar extract, fractions derived from RP-HPLC analysis were examined for their antioxidant effect on oxidatively stressed PBMC. The triterpenoid fraction revealed remarkable increase in intracellular GSH. We suggest GSH restoration and downregulation of CD36 mRNA expression as the pathways via which P. lentiscus triterpenes exert antioxidant/antiatherogenic effect. Additionally, our results provide strong evidence of the resin's antiatherogenic effect; therefore it is credited with beneficial health aspects.  相似文献   
88.

Rationale

Irritant chlorination products in swimming pools can cause respiratory problems in swimmers but their possible implication in allergies development is still unclear.

Objectives

To assess prospectively whether early-life attendance at chlorinated pools increases the risks of IgE sensitization and of airways inflammation later during childhood.

Methods

We conducted a two-year prospective study among 196 kindergarten children (mean age of 5.7 years, 54% of boys). We measured exhaled nitric oxide (eNO) and aeroallergen-specific IgE in nasal mucosa. Parents completed a questionnaire about the child's health, chlorinated pool attendance and potential confounders.

Main Results

Ever swimming at indoor or outdoor chlorinated pools before the age of three years was associated with higher odds for new-onset IgE sensitization to house dust mite (adjusted odds ratio [aOR] 2.93, 95% confidence interval [CI] 1.14–7.55) and for new-onset increased eNO (>15 ppb; aOR, 4.54, 95% CI 1.48–13.9). For both outcomes, aORs increased dose-dependently with time spent in chlorinated pools with values reaching, respectively, 3.60 (95% CI 1.21–10.7) and 5.92 (95% CI 1.72–20.5) when the cumulative pool attendance exceeded 60 h These risks appeared independently of each other, of parental history of allergies and of pre-existing diseases, including eczema, which at baseline was more prevalent in early swimmers (aOR, 2.91; 95% CI 1.23–6.89). Such associations were not seen with IgE sensitization to pollen or cat allergens.

Conclusion

Attendance at chlorinated swimming pools in early life is associated with higher risks of new-onset airways inflammation and IgE sensitization to house dust mite, independently of other risk factors.  相似文献   
89.
90.
A total of 192 pediatric patients, median age 8.6 years, with high-risk hematological malignancies, underwent haploidentical stem cell transplantation (haplo-HSCT) using post-transplantation cyclophosphamide (PT-Cy), or ex vivo T cell-depleted (TCD) graft platforms, from January 1999 to December 2016 in 10 centers in Spain. Some 41 patients received an unmanipulated graft followed by PT-Cy for graft-vs-host disease (GvHD) prophylaxis. A total of 151 patients were transplanted with CD3-depleted peripheral blood stem cells (PBSCs) by either CD34+ selection, CD3+CD19+ depletion, TCRαβ+CD19+ depletion or CD45RA+ depletion, added to CD34+ selection for GvHD prophylaxis. The PBSCs were the only source in patients following ex vivo TCD haplo-HSCT; bone marrow was the source in 9 of 41 patients following PT-CY haplo-HSCT. Engraftment was achieved in 91.3% of cases. A donor younger than 30 years, and the development of chronic GvHD were positive factors influencing survival, whereas positive minimal residual disease (MRD) before transplant and lymphoid disease were negative factors. The probability of relapse increased with lymphoid malignancies, a donor killer-cell immunoglobulin-like receptor (KIR) haplotype A and positive MRD pretransplant. No difference was found in overall survival, disease-free survival or relapse incidence between the two platforms. Relapse is still of concern in both platforms, and it should be the focus of future efforts. In conclusion, both platforms for haplo-HSCT were effective and could be utilized depending on the comfort level of the center.  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