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   4727篇
  免费   288篇
  国内免费   122篇
耳鼻咽喉   4篇
儿科学   76篇
妇产科学   99篇
基础医学   303篇
口腔科学   10篇
临床医学   744篇
内科学   899篇
皮肤病学   53篇
神经病学   362篇
特种医学   63篇
外科学   482篇
综合类   868篇
预防医学   133篇
眼科学   47篇
药学   807篇
  5篇
中国医学   99篇
肿瘤学   83篇
  2024年   8篇
  2023年   43篇
  2022年   64篇
  2021年   126篇
  2020年   114篇
  2019年   113篇
  2018年   124篇
  2017年   120篇
  2016年   128篇
  2015年   175篇
  2014年   342篇
  2013年   401篇
  2012年   290篇
  2011年   299篇
  2010年   232篇
  2009年   199篇
  2008年   222篇
  2007年   228篇
  2006年   198篇
  2005年   175篇
  2004年   180篇
  2003年   159篇
  2002年   148篇
  2001年   144篇
  2000年   102篇
  1999年   85篇
  1998年   70篇
  1997年   74篇
  1996年   64篇
  1995年   45篇
  1994年   64篇
  1993年   31篇
  1992年   25篇
  1991年   39篇
  1990年   29篇
  1989年   22篇
  1988年   23篇
  1987年   20篇
  1986年   21篇
  1985年   30篇
  1984年   30篇
  1983年   30篇
  1982年   31篇
  1981年   9篇
  1980年   21篇
  1979年   8篇
  1978年   5篇
  1977年   9篇
  1976年   10篇
  1975年   4篇
排序方式: 共有5137条查询结果,搜索用时 10 毫秒
991.
992.
为了能快速、准确地测定酶活性,本文观察了肝素抗凝血浆对酶活性的测定影响。同时测定血浆与血清标本中的AST、ALP、ALT、GGT、LDH、HBDH、CK、ACP活性,并进行相关性分析,实验结果显示血浆与血清AST、ALP、ALT、GGT、LDH、CK、HBDH活性无显著性差异(P>0.05),相关性良好(r=0.8081—0.9928),而ACP则有显著性差异(P<0.01)。本实验表明可用血浆代替血清进行多项酶活性测定。  相似文献   
993.
观察血管成形术后平滑肌细胞增生及再狭窄形成过程,探讨低分子量肝素的抑制作用。  相似文献   
994.
Objectives: As thromboembolism (TE) continues to be one of the principal causes of death in obstetrical patients and as the postpartum period is associated with the highest risk for TE, we sought to determine the risk factors associated with TE following cesarean section (CS).

Methods: A retrospective analysis of patients who had CS at a large tertiary referral center was conducted. Patients were identified through hospital medical records and were contacted approximately 1 year following their CS. Medical records and a questionnaire were used to identify features that were potentially associated with TE. Univariate analysis was used to determine the risk associated with these characteristics.

Results: A total of 2206 patients had a CS, of which 1377 (62%) participated. Of the respondents, 137 patients received heparin (94% received a prophylactic dose, 6% received a therapeutic dose) and the remainder, 1233 patients, did not receive heparin. Seven patients (0.5%) developed a TE and 86% developed a TE within 7 days of CS. The odds ratio (OR) for TE for women with hypertension prior to pregnancy compared to patients who did not receive anticoagulation was 21.28 [95% confidence interval (CI) 4.64–90.13] and for patients who had varicose veins with superficial thrombophlebitis when compared to patients who had received heparin postpartum was 21.01 (95% CI 1.55–288.24).

Discussion: Hypertension and the presence of varicose veins were associated with TE following CS. Larger cohort analyses are required to confirm these associations so that risk scores incorporating these characteristics may accurately predict the occurrence of TE.  相似文献   

995.
目的:观察体外循环(CPB)期间血小板膜糖蛋白Ib(GPIb),颗粒膜蛋白140(GMP-140)及血小板大小的变化。方法:答血流式细胞技术检测19例二尖瓣置换病人CPB前后6个时间点血小板GPIb,GMP-140及血小板大小的动态变化。结果:肝素和CPB均导致部分血小板活化和血小板GBIb的降低(P〈0.05)。血小板的活化和血以GPIb的降低呈正相关(P〈0.05),而血小板的大小无明显改变(  相似文献   
996.
The success in treating ischemia of the heart and the importance of rapid treatment is stimulating much research in the application of a similar approach to the treatment of stroke. A proposed protocol, Scoop the Patient, is offered to bring about time-saving and, therefore, more successful results in stroke care. The protocol would be useful as a guide to action for the public as well as professional and paraprofessional caregivers to stroke patients. The importance of triage for ambulatory as well as ambulance patients is stressed. Very early arrival of the patient at the emergency room provides the doctor with the optimal time in which to initiate IV treatment with anticoagulants or thrombolytics, potentially resulting in reperfusion.  相似文献   
997.
Deep venous thromboses can be divided into two groups according to their pathogenesis, anatomical features and differing responses to therapy. The first and most frequent consists of so-called simple venous thrombosis while the second group, which is less common, comprises severe or recurrent venous thrombosis characterised by a multifactorial pathogenesis, a mixed thrombus rich in platelets and by an incomplete response to both prophylactic and therapeutic treatment with anticoagulants (heparin or vitamin K antagonist). In a randomized, prospective blind study in patients with severe or recurrent venous thrombosis, which included 6 groups each of 100 patients, co-administration of anticoagulants with various types of antiplatelet agent, either with rheological effects (piracetam, buflomedil, pentoxifylline) or without them (dipyridamole), has shown a beneficial potentiating antithrombotic effect with those drugs possessing rheological effects and the absence of this effect with dipyridamole.  相似文献   
998.
Venous malformations are slow‐flow congenital vascular malformations that enlarge as the child ages and may be associated with localised intravascular coagulation, a consumptive coagulopathy characterised by elevated D‐dimer and decreased fibrinogen levels. The authors review the known correlations between localised intravascular coagulation and venous malformation number, size and planes involved, and call attention to the concept of the progression of localised intravascular coagulopathy as the child ages and their venous malformations enlarge. The authors also discuss the identified therapeutic options for its investigation, management and treatment, including compression garments, anti‐coagulation therapy, sclerotherapy, endovascular laser, surgical excision and sirolimus (rapamycin). Evidence for protocol improvements that may be instigated for the optimal physical and medical therapy of venous malformations complicated by localised intravascular coagulopathy is reviewed.  相似文献   
999.
1000.
Summary The significance of baseline coagulation times and plasma concentrations of serine protease inhibitors as determinants of the relationship between heparin activity and its anticoagulant effect has been investigated in vitro. Citrated plasma was prepared from blood obtained from 20 normal subjects, and heparin added to yield concentrations ranging from 0.05 to 1.5 units/ml. The anticoagulant effect was determined by the activated partial thromboplastin time (APTT) and thrombin time (TT). An excellent linear relationship was observed between the natural logarithms (ln) of the coagulation times and heparin activity. Baseline APTT values ranged from 28.4 to 59.7 s and the slope values for the ln APTT vs heparin curves ranged from 1.488 to 3.427 ml/unit. Similar range was observed in the slope values for the ln TT vs heparin curves. There was a highly significant positive correlation between the ln APTT vs heparin slope values and the baseline APTT values (r: 0.905; p<0.001). There was also a weak but statistically significant positive correlation between plasma concentrations of 2 macroglobulin and baseline APTT values (0.02>p>0.01) and slope values of the ln APTT vs heparin curves (0.02>p>0.01). Furthermore, there was a statistically significant positive correlation between plasma concentrations of 1 antitrypsin and baseline TT values (0.05>p>0.02) and slope values of the ln TT vs heparin curves (0.02>p>0.01). Neither baseline APTT and TT values nor slope values of the ln APTT and TT vs heparin curves were statistically significantly related to plasma concentrations of antithrombin III, fibrinogen, or 1 acid glycoprotein. This study has demonstrated that baseline APTT is a major determinant of the anticoagulant response to heparin in vitro, as determined by that same coagulation test, and it illustrates that there is a wide intersubject variation in the anticoagulant response to heparin in vitro.  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