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   10747篇
  免费   693篇
  国内免费   200篇
耳鼻咽喉   146篇
儿科学   150篇
妇产科学   561篇
基础医学   1128篇
口腔科学   182篇
临床医学   1196篇
内科学   1260篇
皮肤病学   193篇
神经病学   835篇
特种医学   269篇
外国民族医学   2篇
外科学   1394篇
综合类   1271篇
一般理论   2篇
预防医学   1771篇
眼科学   79篇
药学   559篇
  3篇
中国医学   197篇
肿瘤学   442篇
  2024年   18篇
  2023年   156篇
  2022年   315篇
  2021年   417篇
  2020年   405篇
  2019年   395篇
  2018年   424篇
  2017年   412篇
  2016年   429篇
  2015年   399篇
  2014年   729篇
  2013年   881篇
  2012年   552篇
  2011年   660篇
  2010年   536篇
  2009年   499篇
  2008年   534篇
  2007年   521篇
  2006年   496篇
  2005年   345篇
  2004年   253篇
  2003年   271篇
  2002年   218篇
  2001年   179篇
  2000年   137篇
  1999年   135篇
  1998年   122篇
  1997年   122篇
  1996年   76篇
  1995年   100篇
  1994年   103篇
  1993年   79篇
  1992年   65篇
  1991年   80篇
  1990年   64篇
  1989年   59篇
  1988年   54篇
  1987年   49篇
  1986年   36篇
  1985年   59篇
  1984年   52篇
  1983年   20篇
  1982年   32篇
  1981年   26篇
  1980年   21篇
  1979年   24篇
  1978年   18篇
  1977年   24篇
  1976年   14篇
  1974年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Continued advances in the understanding and management of congenital heart disease (CHD) mean that over 90% of children born with CHD now survive to adulthood. This in turn results in greater numbers of adult patients presenting for medical and surgical care at non-specialist centres. A simple classification of adult congenital heart disease (ACHD) according to complexity can help clinicians to understand the implications of the specific cardiac anomaly encountered. Issues relating to the conduct of anaesthesia in ACHD patient include careful attention to euvolaemia, the preservation of sinus rhythm and cardiac output, and in complex patients, manipulating the balance between systemic and pulmonary blood flows. Additionally, effective antibiotic prophylaxis and the prevention of either excessive bleeding or thromboembolism are vitally important. It should not be forgotten that although many patients with simple or repaired cardiac lesions may be very well managed in a non-specialist unit, those with Eisenmenger’s syndrome or severe pulmonary hypertension have an extremely high risk of death in the perioperative period, and in all but life-threatening situations should always be managed within specialist centres.  相似文献   
63.
IntroductionSemen induces mucosal changes in the female reproductive tract to improve pregnancy outcomes. Since semen‐induced alterations are likely short‐lived and genital inflammation is linked to HIV acquisition in women, we investigated the contribution of recent semen exposure on biomarkers of genital inflammation in women at high HIV risk and the persistence of these associations.MethodsWe assessed stored genital specimens from 152 HIV‐negative KwaZulu‐Natal women who participated in the CAPRISA 008 trial between November 2012 and October 2014. During the two‐year study period, 651 vaginal specimens were collected biannually (mean five samples per woman). Cervicovaginal lavage (CVL) was screened for prostate‐specific antigen (PSA) by ELISA, whereas Y‐chromosome DNA (YcDNA) detection and quantification were conducted by RT‐PCR, representing semen exposure within 48 hours (PSA+YcDNA+) and semen exposure within three to fifteen days (PSA−YcDNA+). Soluble protein concentrations were measured in CVLs by multiplexed ELISA. T‐cell frequencies were assessed in cytobrushes by flow‐cytometry, and vulvovaginal swabs were used to detect common vaginal microbes by PCR. Linear mixed models adjusting for factors associated with genital inflammation and HIV risk were used to assess the impact of semen exposure on biomarkers of inflammation over multiple visits.ResultsHere, 19% (125/651) of CVLs were PSA+YcDNA+, 14% (93/651) were PSA−YcDNA+ and 67% (433/651) were PSA−YcDNA−. Semen exposure was associated with how often women saw their partners, the frequency of vaginal sex in the past month, HSV‐2 antibody detection, current gonorrhoea infection and Nugent Score. Both PSA detection (PSA+YcDNA+) and higher cervicovaginal YcDNA concentrations predicted increases in several cytokines, barrier‐related proteins (MMP‐2, TIMP‐1 and TIMP‐4) and activated CD4+CCR5+HLA‐DR+ T cells (β = 0.050; CI 0.001 to 0.098; p = 0.046) and CD4+HLA‐DR+ T cells (β = 0.177; CI 0.016 to 0.339; p = 0.032) respectively. PSA detection was specifically associated with raised pro‐inflammatory cytokines (including IL‐6, TNF‐α, IP‐10 and RANTES), and with the detection of BVAB2 (OR = 1.755; CI 1.116 to 2.760; p = 0.015), P. bivia (OR = 1.886; CI 1.102 to 3.228; p = 0.021) and Gardnerella vaginalis (OR = 1.815; CI 1.093 to 3.015; p = 0.021).ConclusionsMore recent semen exposure was associated with raised levels of inflammatory biomarkers and the detection of BV‐associated microbes, which declined by three to fifteen days of post‐exposure. Although transient, semen‐induced alterations may have implications for HIV susceptibility in women.  相似文献   
64.
BackgroundTo summarize our experience with the Boari flap-psoas hitch and compare the indications, perioperative data and outcomes between open and laparoscopic procedures.MethodsThis study retrospectively reviewed 35 patients with complex distal ureteral stricture between January 2015 and April 2019. All patients were treated with Boari flap-psoas hitch by either an open or a laparoscopic procedure. Selection criteria were based on the etiology, comorbidities, medical history, and patient preference.ResultsAll surgeries were performed successfully. The median operation time was 201 min (range, 120 to 300 min), and the median estimated blood loss was 50 mL (range, 20 to 400 mL). The median postoperative hospitalization was 9 days (range, 3 to 46 days). Nineteen patients were treated by the open procedure, and 16 were treated by the transperitoneal laparoscopic procedure. The surgical indication of open surgery was broader than that for laparoscopic surgery. For patients experiencing iatrogenic injury and ureterovesical reimplantation failure, no significant differences in sex, laterality, operative time, ASA score or postoperative hospitalization stay were observed between the two groups. The median estimated blood loss was lower in the laparoscopic group than in the open group (P=0.047). Patients in the open group had more surgical complications than patients in the laparoscopic group (P=0.049). The postoperative follow-up showed the radiological resolution of hydronephrosis in 33 patients.ConclusionsWith the appropriate surgical considerations, Boari flap-psoas hitch is a valid method to bridge distal ureteral defects. For select patients, laparoscopic surgery had advantages being a minimal invasive surgery with less estimated blood loss and fewer surgical complications.  相似文献   
65.
BackgroundPeyonie’s disease (PD) mostly affects males in the fifth decade of life, with a prevalence in the general population ranging between 0.5% and 20.3%. The pathology of PD is characterized by fibrosis of the tunic albuginea of the cavernous bodies of the penis, with the presence of pain in the erection and penile deformity. This is associated with decreased sexual function for both participants. The objective of the study was to investigate the influence of PD pathology on both male patients’ and their female partners’ sexual spheres, and analyze changes in sexual function and perception following penile correction surgery.MethodsProspective study, we included male patients with PD and their female partner sexually active. Patients underwent corporoplasty with multiple plications. The male and female sexuality was evaluated before surgery and three months after male treatment by the Female sexual Function Index (FSFI); International Index of Erectile Function (IIEF); Visual Analogical Scale (VAS).ResultsFrom January 2018 to November 2019 we included 35 couple. The female subjects before partner’s surgery presented dyspareunia, loss of sexual desire, inability to achieve orgasm, and sexual dissatisfaction. At three months after surgical treatment there was an improvement of sexual function in both male patients and female partners (desire P<0.0001, arousal P<0.0001, lubrification P<0.0001, orgasm P<0.0001, satisfaction P<0.0001, pain P<0.0001). As regarding male patients the pain decreased significantly (VAS score from 6 to 2.5), while there was no statistically significant improvement in erectile function (P=0.05).ConclusionsOur findings suggest that a viable approach to treatment of PD patients that involves their partners could lead to better functional and psychological results.  相似文献   
66.
《Vaccine》2021,39(37):5240-5250
Given our global interconnectedness, the COVID-19 pandemic highlights the urgency of building a global system that can support both routine and pandemic/epidemic adult immunization. As such, a framework to recommend vaccines and build robust platforms to deliver them to protect the rapidly expanding demographic of older adults is needed. Adult immunization as a strategy has the broad potential to preserve and improve medical, social, and economic outcomes, including maintaining functional ability that benefits older adults, their families, communities, and countries. While we will soon have multiple vaccines against COVID-19, we must recognize that we already have a variety of vaccines against other pathogens that can keep adults healthier. They can prevent simultaneous co-infection with COVID-19, and may favorably impact- the outcome of a COVID-19 illness. Further, administering a vaccine against COVID-19 requires planning now to determine delivery strategies impacting how older adults will be immunized in a timely manner. A group of international experts with various backgrounds from health and aging disciplines met to discuss the evidence case for adult immunization and crucial knowledge gaps that must be filled in order to implement effective policies and programs for older adult immunization. This group, coming together as the International Council on Adult Immunization (ICAI), outlined a high-level roadmap to catalyze action, provide policy guidance, and envision a global adult immunization platform that can be adapted by countries to fit their local contexts. Further meetings centered around the value of adult immunization, particularly in the context of COVID-19. There was agreement that programs to deliver existing influenza, pneumococcal, herpes zoster vaccines, and future COVID-19 vaccines to over a billion older adults who are at substantially higher risk of death and disability due to vaccine-preventable diseases are more urgent than ever before. Here we present a proposed framework for delivering routine and pandemic vaccines. We call upon the global community and governments to prioritize action for integrating robust adult immunization programs into the public health agenda.  相似文献   
67.
目的:研究照料失能配偶对老年女性抑郁程度的影响。方法:利用“中国健康与养老追踪调查”2015年全国数据,通过工具变量回归进行分析。结果:相比于没有照料配偶的女性,参与配偶照料的女性抑郁得分更高(P<0.01)。结论:提供长期照料会增加老年女性的抑郁程度。制定老年长期照料政策时应关注女性照料者的心理健康。  相似文献   
68.
《Vaccine》2022,40(24):3338-3344
Nationwide population-based surveillance for invasive pneumococcal disease (IPD) is being conducted in few Asian countries. We aimed to evaluate the clinical characteristics and serotype distribution among Japanese adult patients with IPD after introduction of the pediatric 13-valent pneumococcal conjugate vaccine (PCV13) in 2013. IPD surveillance was conducted among adults between 2013 and 2019, and 1,995 patients were analyzed by time period (early, 2013–2015; middle, 2016–2017; late, 2018–2019). We found that the period of 2018–2019 was independently associated with a lower risk of fatal outcome, compared with the period of 2013–2015. The proportion of those with serotype PCV13-nonPCV7 decreased significantly in patients aged 15–64 years and in those aged ≥ 65 years within 3 years after the introduction of pediatric PCV13. By contrast, the proportion of those with nonvaccine serotype increased significantly in those aged ≥ 65 years, but not in those aged 15–64 years. No significant change was found in the proportion of 23-valent polysaccharide pneumococcal vaccine (PPSV23)-nonPCV13 in both of adults aged 15–64 years and ≥ 65 years. The proportions of PCV15-, PCV20- and PCV24-covered serotypes were 38%, 56% and 58% in adult patients with IPD aged ≥ 65 years during the late period. Our data on the serotype distribution support an indirect effect from pediatric PCV13 use among adults, and afford a basis for estimates of protection against IPD by vaccination with newly developed PCVs in older adults in Japan.  相似文献   
69.
采用CT成像和图像分析技术,在尸体研究的基础上,对50例女性样本(18~23岁)进行全身CT横断层扫描、图像分析和测算以及建立数学模型等方面的研究。获得了人体的质量分布、质心位置和转动惯量等惯性参数。据此,建立了直接计算中国女性青年人体各环节惯性参数的二元回归方程。为中国人体运动学和动力学研究提供了基础数据;也为运动员的选材提供了有力的手段。  相似文献   
70.
A repetition of certain experiments done 2 years previously with two eye color mutants,brown andscarlet, inDrosophila melanogaster was undertaken to reconfirm results; however, initial tests revealed that strains or conditions had changed so that females were less discriminating. Testing was undertaken with changes in genetic background and certain laboratory conditions, with single females courted by equal numbers of two eye color types of males (3 red,R: 3 orange,O). These eye colors were produced as (1) mutants off the shelf, (2) recombinants from an outcross to a wild-type strain (CS), (3) mutants as in Experiment 1 but with male types stored either together or separately, and (4) recombinants from a double outcross of flies from Experiment 2 to hybrids from two additional wild strains,LS andOR. Experiment 4 producedR andO males that courted nearly equally (as in previous experiments), in contrast with about 70% courtship byR males in the other experiments. Females discriminated in favor of those second to court in G0, G1, and a repeat of G0; however, with two generations of inbreeding, discrimination by this criterion lessened to become nonsignificant. In Experiments 1 and 2,O females favored second-courting males, butR females in hose experiments and all females in Experiment 3 mated more randomly. Effects of storing males either together or separately were not significant. About 20–30% of the females (low threshold) were highly receptive immediately after first courtship. Those trials plus any in which only a single type of male courted were omitted from estimations of female discrimination; a possible bias incurred by such omission against females that might have initial preferences was found to be nonsignificant. Discriminating ability was discussed as a fitness property inDrosophila populations.This research was supported in part by National Science Foundation Grant DEB 79-03259.  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