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   5474篇
  免费   359篇
  国内免费   42篇
耳鼻咽喉   88篇
儿科学   208篇
妇产科学   65篇
基础医学   551篇
口腔科学   100篇
临床医学   453篇
内科学   1080篇
皮肤病学   147篇
神经病学   322篇
特种医学   258篇
外国民族医学   1篇
外科学   900篇
综合类   138篇
一般理论   6篇
预防医学   319篇
眼科学   148篇
药学   664篇
中国医学   40篇
肿瘤学   387篇
  2023年   44篇
  2022年   157篇
  2021年   203篇
  2020年   110篇
  2019年   144篇
  2018年   178篇
  2017年   105篇
  2016年   154篇
  2015年   148篇
  2014年   188篇
  2013年   261篇
  2012年   382篇
  2011年   352篇
  2010年   209篇
  2009年   186篇
  2008年   300篇
  2007年   301篇
  2006年   274篇
  2005年   252篇
  2004年   222篇
  2003年   209篇
  2002年   168篇
  2001年   131篇
  2000年   114篇
  1999年   108篇
  1998年   51篇
  1997年   46篇
  1996年   50篇
  1995年   51篇
  1994年   41篇
  1993年   53篇
  1992年   74篇
  1991年   73篇
  1990年   56篇
  1989年   53篇
  1988年   55篇
  1987年   37篇
  1986年   35篇
  1985年   53篇
  1984年   42篇
  1983年   25篇
  1982年   16篇
  1981年   14篇
  1979年   24篇
  1978年   12篇
  1976年   9篇
  1974年   9篇
  1972年   10篇
  1971年   12篇
  1968年   9篇
排序方式: 共有5875条查询结果,搜索用时 5 毫秒
81.

Purpose

Visual performance following toric intraocular lens implantation for cataract with moderate and severe astigmatism.

Setting

Cataract services, Shroff Eye Centre, New Delhi, India.

Design

Case series.

Method

This prospective study included 64 eyes of 40 patients with more than 1.50 dioptre (D) of pre-existing corneal astigmatism undergoing phacoemulsification with implantation of the AcrySof® toric IntraOcular Lens (IOL). The unaided visual acuity (UCVA), best corrected visual acuity (BCVA), residual refractive sphere and refractive cylinders were evaluated. Toric IOL axis and alignment error was measured by slit lamp method and Adobe Photoshop (version 7) method. Patient satisfaction was evaluated using a satisfaction questionnaire at 3 months.

Results

The mean residual refractive astigmatism was 0.57 D at the final follow-up of 3 months. Mean alignment error was 3.44 degrees (SD = 2.60) by slit lamp method and 3.88 degrees (SD = 2.86) by Photoshop method. Forty-six (71.9%) eyes showed misalignment of 5 degrees or less, and 60 (93.8%) eyes showed misalignment of 10 degrees or less. The mean log MAR UCVA at 1st post-op day was 0.172 (SD = 0.02), on 7th post-op day was 0.138 (SD = 0.11), and on 30th post-op day was 0.081 (SD = 0.11). The mean log MAR BCVA at three months was −0.04 (SD = 0.76).

Conclusion

We believe that implantation of AcrySof® toric IOL is an effective, safe and predictable method to correct high amounts of corneal astigmatism during cataract surgery.  相似文献   
82.
To characterize the genomic context of New Delhi metallo-β-lactamase-1 (NDM-1) and Klebsiella pneumoniae carbapenemase (KPC), we sequenced 78 Enterobacteriaceae isolates from Pakistan and the United States encoding KPC, NDM-1, or no carbapenemase. High similarities of the results indicate rapid spread of carbapenem resistance between strains, including globally disseminated pathogens.  相似文献   
83.
Pharmaceutical Research - Surface area and surface energy of pharmaceutical powders are affected by milling and may influence formulation, performance and handling. This study aims to decouple the...  相似文献   
84.
BackgroundReference values for cardiac magnetic resonance imaging (cMRI) in children and young adults are scarce. This leads to risk stratification of patients with congenital heart diseases being based on volumes indexed to body surface area (BSA). We aimed to produce cMRI Z score equations for ventricular volumes in children and young adults and to test whether indexing to BSA resulted in an incorrect assessment of ventricular dilation according to sex, body composition, and growth.MethodsWe retrospectively included 372 subjects aged < 26 years with either normal hearts or conditions with no impact on ventricular volumes (reference group), and 205 subjects with repaired tetralogy of Fallot (TOF) aged < 26 years. We generated Z score equations by means of multivariable regression modelling. Right ventricular dilation was assessed with the use of Z scores and compared with indexing to BSA in TOF subjects.ResultsVentricular volume Z scores were independent from age, sex, and anthropometric measurements, although volumes indexed to BSA showed significant residual association with sex and body size. In TOF subjects, indexing overestimated dilation in growing children and underestimated dilation in female compared with male subjects, and in overweight compared with lean subjects.ConclusionsIndexed ventricular volumes measured with cMRI did not completely adjust for body size and resulted in a differential error in the assessment of ventricular dilation according to sex and body size. Our proposed Z score equations solved this problem. Future studies should evaluate if ventricular volumes expressed as Z scores have a better prognostic value than volumes indexed to BSA.  相似文献   
85.
An in vitro angiogenesis system was designed for screening angiogenic agonists and antagonists. In order to obtain large quantities of cells and reproducibility, human endothelial cells with extended life spans were developed by retroviral transfection. The resulting cells grown in a serum-free medium containing endothelial cell growth supplement (ECGS) have a telomerase activity, extended life spans of at least 21 passages, and an endothelial cell phenotype (diI-acetylated-LDL upake, factor VIII-related antigen, VEGFR-1 and R-2, and tissue-type plasminogen activator (tPA)) that resembled that of unaltered primary endothelial cells. Exceptions were (i) a higher expression of tPA, and (ii) a non-significant growth response to FGF-2 or VEGF stimulation. Within three-dimensional fibrin gels, specific cell clones rapidly formed tubular structures in a more reproducible manner than those observed with low-passage primary cells. Tube formation by primary endothelial cells and those with extended life spans was dependent upon FGF-2 and ECGS, respectively. Both cell types produced FGF-2 and VEGF cytokines. Increasing doses of suramin significantly decreased the size of microvessels formed by both cell lines. These functional results indicate that a vascular matrix system containing human cells with extended life spans can be successfully utilized as an in vitro assay for antiangiogenic compounds.  相似文献   
86.
87.
Summary Objective: To assess the frequency of adverse drug reaction in patients with fibromyalgia in relation to medications prescribed for this condition. To evaluate the potential role of the P450IID6 phenotype in the pathogenesis of these adverse drug reactions. Methods: Thirty-five patients with fibromyalgia were assessed using a structured questionnaire with demographic and clinical data and perceived adverse drug reactions. A sample of 60 patients with rheumatoid arthritis and 62 patients with localized back pain served as controls. The P450IID6 phenotype was determined for each of the fibromyalgia patients. Results: Overall, 141 patients had used NSAID and 79 (56%) of them reported adverse effects. Antidepressant drugs were used by 68 patients and 35 (51%) patients had adverse effects. Muscle relaxant drugs were used by 48 patients and 15 (31%) of them reported side effects. Analgesics were used by 122 patients and 22 (18%) had experienced adverse effects. Statistical differences in the frequency of adverse effects were found with antidepressant drugs in the fibromyalgia group, compared with rheumatoid arthritis (p=0.01) and back pain (p=0.02). Four of the 35 patients (11.4%) had a metabolic ratio (M.R.) greater than 0.30 (log M.R.=–0.52) indicative of the poor metabolizers (PM) phenotype. M.R. varied from 0.005 (log M.R.=–2.30) to 4.99 (log M.R.=0.70). Conclusions: The problem of adverse drug reactions in fibromyalgia patients does not appear to correlate with the PM phenotype of the P450IID6 oxidative enzyme. It also is unlikely that altered xenobiotic detoxification attributable to this PM phenotype would have a significant role in the development of fibromyalgia.  相似文献   
88.
89.
Knowledge of historical demography and contemporary social stratification can be valuable in understanding disease patterns, including genetic disorders, especially in communities that have a high prevalence of endogamous and/or consanguineous marriages. This paper provides a background to the religious, historical and socio-cultural factors that have helped define the bounds of endogamy for Muslims in undivided India and more specifically since the creation of Pakistan. The preference for endogamous marriage is based on the clan-oriented nature of the society, which values and actively seeks similarities in social group identity based on several factors, including religious, sectarian, ethnic, and tribal/clan affiliation. Religious affiliation is itself multi-layered and includes religious considerations other than being Muslim, such as sectarian identity (e.g. Shia or Sunni, etc.) and religious orientation within the sect (Isnashari, Ismaili, Ahmedi, etc.). Both ethnic affiliation (e.g. Sindhi, Baloch, Punjabi, etc.) and membership of specific biraderis or zat/quoms are additional integral components of social identity. Within the bounds of endogamy defined by the above parameters, close consanguineous unions are preferential due to a congruence of key features of group- and individual-level background factors.  相似文献   
90.
Objectives/BackgroundMedical therapy is the first line of treatment for intracranial atherosclerotic disease (ICAD). Percutaneous transluminal angioplasty and stenting (PTAS) are mainly considered for those patients with severe stenosis and recurrent events despite aggressive medical therapy. In this review, we discuss the application of PTAS as a treatment option for ICAD and its future prospect.Materials and MethodsWe did the literature review of the key articles and guidelines to elaborate on the role of PTAS in the management of ICAD based on the current data and expert opinion. We searched PubMed, Google Scholar, and Scopus up to August 2020, and included articles published only in the English language.ResultsSince the publication of the results from SAMMPRIS and VISSIT trials, stenting is no longer recommended for secondary stroke prevention in patients with symptomatic ICAD. However, recent clinical studies on intracranial stenting for a subgroup of ICAD patients have shown promising results, likely due to better patient selection and continued advancement of endovascular techniques.ConclusionThere exists a lack of consensus regarding the best endovascular treatment approach (e.g., angioplasty alone or balloon mounted stent vs. self-expanding stent with or without prior angioplasty) or management of in-stent restenosis. Another area of clinical controversy relates to the ideal use and duration of antiplatelet therapy.  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