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   2880篇
  免费   130篇
  国内免费   11篇
耳鼻咽喉   8篇
儿科学   113篇
妇产科学   67篇
基础医学   510篇
口腔科学   22篇
临床医学   239篇
内科学   580篇
皮肤病学   29篇
神经病学   225篇
特种医学   206篇
外科学   489篇
综合类   24篇
一般理论   2篇
预防医学   120篇
眼科学   20篇
药学   200篇
中国医学   6篇
肿瘤学   161篇
  2023年   13篇
  2022年   30篇
  2021年   61篇
  2020年   33篇
  2019年   31篇
  2018年   50篇
  2017年   44篇
  2016年   61篇
  2015年   69篇
  2014年   101篇
  2013年   116篇
  2012年   161篇
  2011年   184篇
  2010年   108篇
  2009年   121篇
  2008年   184篇
  2007年   218篇
  2006年   205篇
  2005年   190篇
  2004年   167篇
  2003年   183篇
  2002年   192篇
  2001年   52篇
  2000年   33篇
  1999年   33篇
  1998年   34篇
  1997年   37篇
  1996年   43篇
  1995年   27篇
  1994年   16篇
  1993年   17篇
  1992年   12篇
  1991年   10篇
  1990年   14篇
  1989年   11篇
  1988年   11篇
  1987年   11篇
  1986年   9篇
  1985年   12篇
  1983年   7篇
  1982年   10篇
  1981年   8篇
  1978年   6篇
  1976年   5篇
  1975年   4篇
  1973年   4篇
  1972年   8篇
  1971年   7篇
  1970年   8篇
  1939年   5篇
排序方式: 共有3021条查询结果,搜索用时 15 毫秒
91.
Randomized controlled trials (RCTs) on the topic of physical training and blood coagulation are rare and the effects are unclear. The aim of this study was to investigate whether endurance training adjusts blood coagulation and fibrinolysis at rest and after exercise. The study included 50 healthy untrained non-smokers randomized into training (TR 49 ± 6 years) or control group (CO 48 ± 6 years). Each subject performed an exercise test adjusted at 80 % individual anaerobic threshold (IAT) for 60 min before and after 12 weeks (80 % IAT: before TR 123 ± 20, CO 125 ± 26 W; after TR 148 ± 23 W, CO 127 ± 25 W; mean ± SD). Blood was taken at rest and after exercise to determine coagulation (e.g., aPTT, thrombin potential, TAT, F1+2, several coagulation factors) and fibrinolytic (e.g., tPA, PAI) parameters. The training intervention induced an elevation of physical capacity in TR by 17 % (rel. VO2max) that led to a statistical relevant prolongation of aPTT at rest. Although absolute power output during the second exercise test was 20 % higher in TR, we detected an attenuated exercise-induced decrease of aPTT and attenuated increase of F1+2 after training. Resting levels of tPA- and PAI-Ag decreased slightly but not significantly after training. Exercise-induced changes were comparable after training in spite of higher power output in TR. Although the effects are small in healthy men, training modifies exercise-induced blood coagulation positively. The fact that exercise-induced changes in blood coagulation and fibrinolysis are rather attenuated or unchanged in the training group, in spite of a 20 % higher absolute power output during exercise, substantiates the adjusting effect of endurance training and the importance of physical fitness in primary prevention.  相似文献   
92.
Abstract

A new approach to assessing family attachment patterns is presented, using a composite measure of individual attachment representations based on the Bartholomew Attachment Interview. A cluster analysis yielded three different patterns in a sample of N = 37 families with a drug dependent adolescent (age 14 – 25) and both biological parents. A “triangulated” pattern (mothers: preoccupied; fathers: dismissing; adolescents: fearful) was found in 65% of the sample. A total of 19% showed an “insecure” pattern (mothers, fathers, and adolescents: fearful) and 16% a “near-secure” pattern (mothers and adolescents: secure; fathers preoccupied). Preliminary comparisons between these groups indicate differences in comorbid psychiatric disorders, in individual and family functioning, but not in addiction severity. There is a trend towards differences in outcome of family therapy. Implications for treatment and further research are discussed.  相似文献   
93.
94.
95.
Recommendations concerning the management of hemoglobin levels and hematocrit in patients on extracorporeal membrane oxygenation (ECMO) still advise maintenance of a normal hematocrit. In contrast, current transfusion guidelines for critically ill patients support restrictive transfusion practice. We report on a series of patients receiving venovenous ECMO (vvECMO) for acute respiratory distress syndrome (ARDS) treated according to the restrictive transfusion regimen recommended for critically ill patients. We retrospectively analyzed 18 patients receiving vvECMO due to severe ARDS. Hemoglobin concentrations were kept between 7 and 9 g/dL with a transfusion trigger at 7 g/dL or when physiological transfusion triggers were apparent. We assessed baseline data, hospital mortality, time on ECMO, hemoglobin levels, hematocrit, quantities of packed red blood cells received, and lactate concentrations and compared survivors and nonsurvivors. The overall mortality of all patients on vvECMO was 38.9%. Mean hemoglobin concentration over all patients and ECMO days was 8.30 ± 0.51 g/dL, and hematocrit was 0.25 ± 0.01, with no difference between survivors and nonsurvivors. Mean numbers of given PRBCs showed a trend towards higher quantities in the group of nonsurvivors, but the difference was not significant (1.97 ± 1.47 vs. 0.96 ± 0.76 units; P = 0.07). Mean lactate clearance from the first to the third day was 45.4 ± 28.3%, with no significant difference between survivors and nonsurvivors (P = 0.19). In our cohort of patients treated with ECMO due to severe ARDS, the application of a restrictive transfusion protocol did not result in an increased mortality. Safety and feasibility of the application of a restrictive transfusion protocol in patients on ECMO must further be evaluated in randomized controlled trials.  相似文献   
96.
97.
98.
Udo -D. Matzke 《Der Internist》2000,5(6):M184-M185
Wahr ist, dass die Menschen umso gesünder sie sind, je wohlhabender das Land ist, in dem sie leben. Wenn es den Anschein hat, es gäbe heute mehr Kranke als früher, so liegt das an einem Paradox: Je ausgereifter die medizinische Versorgung wird, desto mehr Behandlungsbedürftige gibt es.  相似文献   
99.
Paroxysmal nocturnal haemoglobinuria (PNH) is a clonal haematopoietic disorder characterized by chronic or intermittent intravascular haemolysis, variable cytopenia and an increased risk of thrombosis. Stem cell transplantation (SCT) is a curative therapeutic option, but its risks must be carefully weighed against the natural course of PNH. World-wide experience with SCT for PNH in the paediatric age group is scarce. We report on two adolescents suffering from PNH with life-threatening complications who were successfully transplanted from unrelated donors. Indications and techniques of SCT in childhood PNH are discussed and an overview of the literature is given.  相似文献   
100.
An easy and efficient route to synthesize gel materials based on polymeric ionic liquids (PILs) is presented. The radical polymerization of imidazolium (Im)‐based ionic liquids (ILs) bearing a vinyl group ([VEIm][Br], [VEIm][Ac], [VBIm][Br], [VBIm][Cl]) with crosslinker (CL) N,N′‐methylenebisacrylamide (Bis) in water results in polyionic liquid hydrogels. Thermal and mechanical properties (tensile and compression tests) are investigated and compared with two different types of hydrogels. One is a polyacrylamide (PAAm) hydrogel having covalent‐type crosslinking. The other is an alginate‐based hydrogel having ionic‐type crosslinking. Prepared IL‐hydrogel materials provide favorable flexibility, adjustable by varying the CL ratio and water content. The higher the CL ratio is, the higher the fragility of the gel matrix. The gelation time of the hydrogels depends on the alkyl chain length, as well as the size of the anion.

  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