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   15168篇
  免费   1097篇
  国内免费   65篇
耳鼻咽喉   203篇
儿科学   253篇
妇产科学   201篇
基础医学   2227篇
口腔科学   158篇
临床医学   1531篇
内科学   3604篇
皮肤病学   754篇
神经病学   1413篇
特种医学   646篇
外国民族医学   10篇
外科学   2309篇
综合类   41篇
一般理论   5篇
预防医学   680篇
眼科学   203篇
药学   949篇
中国医学   14篇
肿瘤学   1129篇
  2024年   18篇
  2023年   161篇
  2022年   279篇
  2021年   644篇
  2020年   347篇
  2019年   539篇
  2018年   648篇
  2017年   416篇
  2016年   480篇
  2015年   553篇
  2014年   732篇
  2013年   869篇
  2012年   1315篇
  2011年   1301篇
  2010年   714篇
  2009年   646篇
  2008年   978篇
  2007年   946篇
  2006年   813篇
  2005年   762篇
  2004年   657篇
  2003年   560篇
  2002年   490篇
  2001年   116篇
  2000年   115篇
  1999年   101篇
  1998年   90篇
  1997年   66篇
  1996年   67篇
  1995年   61篇
  1994年   49篇
  1993年   39篇
  1992年   72篇
  1991年   80篇
  1990年   62篇
  1989年   54篇
  1988年   43篇
  1987年   47篇
  1986年   45篇
  1985年   33篇
  1984年   28篇
  1983年   35篇
  1982年   36篇
  1981年   16篇
  1980年   22篇
  1979年   26篇
  1978年   26篇
  1977年   18篇
  1974年   14篇
  1972年   13篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
The purpose of this prospective randomized study was to evaluate use of a hyaluronan-rich transfer medium in fresh and frozen-thawed single blastocyst transfer. The study included 279 single blastocyst transfers in women aged<37 years in their first, second or third treatment cycle. According to the type of single blastocyst transfer (fresh elective or frozen-thawed) the women were divided into two study and two control groups. In both study groups (n=130) transfers were performed using hyaluronan and in the control groups (n=149) a conventional transfer medium was used. The results indicate that fresh elective single blastocyst transfer with hyaluronan results in significantly higher pregnancy rates in a selected subgroup of women; those with >or=2 blastocysts developed to day 5 and a previous implantation failure (55% versus 10%; P=0.012). Overall pregnancy rates after fresh elective and frozen-thawed single blastocyst transfer were similar in both study and control groups.  相似文献   
92.
BackgroundWomen are nearly twice as likely as men to suffer from major depressive disorder. Yet, there is a dearth of studies comparing the clinical outcomes of women and men with treatment-resistant depression (TRD) treated with similar augmentation strategies. We aimed to evaluate the effects of the augmentation strategies in women and men at the McGill University Health Center.MethodsWe reviewed health records of 76 patients (42 women, 34 men) with TRD, treated with augmentation strategies including antidepressants (AD) with mood stabilizers (AD+MS), antipsychotics (AD+AP), or in combination (AD+AP+MS). Clinical outcomes were determined by comparing changes on the 17-item Hamilton Depression Rating Scale (HAMD-17), Montgomery-Åsberg Depression Rating Scale (MADRS), Quick Inventory of Depressive Symptomatology (QIDS-C16), and Clinical Global Impression rating scale (CGI-S) at the beginning and after 3 months of an unchanged treatment. Changes in individual items of the HAMD-17 were also compared between the groups.ResultsWomen and men improved from beginning to 3 months on all scales (P < .001, η p2 ≥ 0.68). There was also a significant sex × time interaction for all scales (P < .05, η p2 ≥ 0.06), reflecting a greater improvement in women compared with men. Specifically, women exhibited greater improvement in early (P = .03, η p2 = 0.08) and middle-of-the-night insomnia (P = .01, η p2 = 0.09) as well as psychomotor retardation (P < .001 η p2 = 0.16) and psychic (P = .02, η p2 = 0.07) and somatic anxiety (P = .01, η p2 = 0.10).ConclusionsThe combination of AD+AP/MS generates a significantly greater clinical response in women compared with men with TRD, supporting the existence of distinct pharmacological profiles between sexes in our sample. Moreover, they emphasize the benefit of augmentation strategies in women, underscoring the benefit of addressing symptoms such as insomnia and anxiety with AP and MS.  相似文献   
93.
Spark Plasma Sintering (SPS) has become a conventional and promising sintering method for powder consolidation. This study aims to well understand the mechanisms of densification encountered during SPS treatments, especially in the early stages of sintering. The direct current (DC) electrical behavior of copper granular medium is characterized. Their properties are correlated with their microstructural evolutions through post-mortem scanning electron microscope (SEM) observations to allow a thorough understanding of the involved Branly effect that is suspected to occur in SPS. The electrical response is studied by modifying the initial thickness of the oxide layer on particles surfaces and applying various mechanical loads on the granular medium. Without load and at low current, the measured quasi-reversible behavior is connected to the formation of spots at the microcontacts between the particles. By increasing the current, the Branly transition from an insulating to a conductive state suddenly occurs. The insulating oxide layer is destroyed, and micro-bridges are created. The application of a mechanical pressure strongly modifies the DC Branly effect. Increasing low stress leads to a strong decrease in the breakdown field. For high-applied pressure, successive drops in the electric field are detected during the electrical transition. These successive drops are induced by microcracking of the insulating oxide layer.  相似文献   
94.
The taxonomic classification of viral sequences is frequently used for the rapid identification of pathogens, which is a key point for when a viral outbreak occurs. Both Oxford Nanopore Technologies (ONT) MinION and the Illumina (NGS) technology provide efficient methods to detect viral pathogens. Despite the availability of many strategies and software, matching them can be a very tedious and time-consuming task. As a result, we developed PIMGAVir and Vir-MinION, two metagenomics pipelines that automatically provide the user with a complete baseline analysis. The PIMGAVir and Vir-MinION pipelines work on 2nd and 3rd generation data, respectively, and provide the user with a taxonomic classification of the reads through three strategies: assembly-based, read-based, and clustering-based. The pipelines supply the scientist with comprehensive results in graphical and textual format for future analyses. Finally, the pipelines equip the user with a stand-alone platform with dedicated and various viral databases, which is a requirement for working in field conditions without internet connection.  相似文献   
95.
96.
Antigammaglobulins of IgG, IgA and IgM classes were measured in normal individuals and in patients with osteoarthritis or rheumatoid arthritis. Serum IgG and IgA and synovial fluid IgG antigammaglobulin levels were significantly higher in patients with rheumatoid arthritis than in other individuals, with highest levels occurring in patients with positive latex fixation tests. IgM antigammaglobulins were elevated only in patients with latex positive rheumatoid arthritis. Increased serum levels of IgG, IgA and IgM antigammaglobulins were each associated with clinical findings of severe rheumatoid arthritis. Increased levels of serum and synovial fluid IgG and IgM antigammaglobulins were each associated with diminished serum and synovial fluid complement levels.  相似文献   
97.
98.
Phytonutrients comprise many different chemicals, including carotenoids, indoles, glucosinolates, organosulfur compounds, phytosterols, polyphenols, and saponins. This review focuses on the human healthcare benefits of seven phytochemical families and highlights the significant potential contribution of phytonutrients in the prevention and management of pathologies and symptoms in the field of family health. The structure and function of these phytochemical families and their dietary sources are presented, along with an overview of their potential activities across different health and therapeutic targets. This evaluation has enabled complementary effects of the different families of phytonutrients in the same area of health to be recognized.  相似文献   
99.
Background  Cancer patients undergoing major abdominal or pelvic surgery are at considerable risk of venous thromboembolism (VTE). The genesis of thromboses in malignancy is complicated, and reflects the interaction and derangement of multiple molecular pathways. Furthermore, the nature and location of the cancer, as well as the type surgery involved, are thought to affect the level of VTE risk. These considerations may therefore affect treatment decisions. Methods  We performed multiple Medline searches with terms including but not limited to VTE, cancer, surgery, abdominal, colorectal, unfractionated heparin (UFH), and low-molecular-weight heparin (LMWH) to identify reviews, meta-analyses, nonrandomized and randomized controlled trials, and clinical guidelines relating to management of VTE in patients with abdominal cancer. Results  VTE incidence in patients with malignancy varied according to cancer type, location, stage of progression, and the use of catheters and/or chemotherapy. Thromboprophylaxis with UFH or LMWH reduces the risk of developing VTE in these patients. However, LMWHs have a favorable risk-benefit profile over UFH and extending the duration prophylaxis may improve outcomes. Conclusion  A number of recommendations can be made for the prevention of VTE in patients undergoing abdominal or pelvic surgery for cancer: (1) risk-stratify all patients according to defined evidence-based guidelines; (2) for most abdominal surgical oncology patients at risk, use of both an anticoagulant and mechanical means are indicated and beneficial; and (3) consider extended-duration prophylaxis (up to 28 days) in those patients with major abdominal/pelvic operations and impaired mobility, preferably with LMWH.  相似文献   
100.
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