全文获取类型
收费全文 | 1984篇 |
免费 | 265篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 54篇 |
妇产科学 | 40篇 |
基础医学 | 183篇 |
口腔科学 | 39篇 |
临床医学 | 254篇 |
内科学 | 513篇 |
皮肤病学 | 29篇 |
神经病学 | 211篇 |
特种医学 | 77篇 |
外科学 | 403篇 |
综合类 | 25篇 |
预防医学 | 147篇 |
眼科学 | 40篇 |
药学 | 122篇 |
中国医学 | 1篇 |
肿瘤学 | 146篇 |
出版年
2023年 | 15篇 |
2022年 | 18篇 |
2021年 | 35篇 |
2020年 | 33篇 |
2019年 | 18篇 |
2018年 | 38篇 |
2017年 | 54篇 |
2016年 | 61篇 |
2015年 | 99篇 |
2014年 | 165篇 |
2013年 | 188篇 |
2012年 | 95篇 |
2011年 | 79篇 |
2010年 | 129篇 |
2009年 | 129篇 |
2008年 | 71篇 |
2007年 | 56篇 |
2006年 | 61篇 |
2005年 | 48篇 |
2004年 | 43篇 |
2003年 | 55篇 |
2002年 | 45篇 |
2001年 | 47篇 |
2000年 | 25篇 |
1999年 | 42篇 |
1998年 | 42篇 |
1997年 | 51篇 |
1996年 | 39篇 |
1995年 | 35篇 |
1994年 | 22篇 |
1993年 | 15篇 |
1992年 | 15篇 |
1991年 | 16篇 |
1990年 | 16篇 |
1989年 | 15篇 |
1988年 | 18篇 |
1987年 | 13篇 |
1986年 | 19篇 |
1985年 | 25篇 |
1983年 | 23篇 |
1982年 | 16篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 21篇 |
1977年 | 14篇 |
1976年 | 15篇 |
1975年 | 14篇 |
1973年 | 12篇 |
1972年 | 13篇 |
1971年 | 15篇 |
排序方式: 共有2294条查询结果,搜索用时 0 毫秒
31.
Clinton H. Toewe II 《Teaching and learning in medicine》2013,25(4):192-193
Background: Internal medicine clinical clerkships usually emphasize student learning of hypothesis generation, problem solving, and patient management. At our school we are concerned that clinical teaching unit (CTU)-based patient exposure is not fostering development of these skills. Purposes: We evaluated our clerks' interactions with patients on our CTUs to document whether the timing of student exposure to patients is conducive to the acquisition of basic clinical skills. Methods: Once per week for 8 weeks, we met with all internal medicine clerks on the CTUs at our 4 teaching hospitals. Each student completed a questionnaire related to each patient worked up in the previous week. We specifically documented when the first interaction occurred with each patient. We also asked students for their perceptions of the learning experiences. Results: Clinical clerks usually first interact with their patients after initial data acquisition, hypothesis generation, and ordering of investigations and therapy have been completed by other physicians. Students perceive that meeting patients late in the hospitalization is educationally disadvantageous. Conclusions: Our clinical clerks usually interact with their patients late in the hospitalization and are therefore deprived of the opportunity to develop the key clinical skills of hypothesis generation, problem-solving, and investigation and management of patients. 相似文献
32.
Stroke is the third most common cause of death and the leading cause of disability in the United States. Management of identifiable risk factors and careful selection of patients for operative intervention constitute the current approach to reducing the morbidity and mortality associated with stroke. A carefully performed carotid endarterectomy (CEA), which has a low periprocedural complication rate, is the only form of mechanical cerebral revascularization for which definitive evidence of clinical effectiveness has been reported. Recently, retrospective case reports and case series have demonstrated the feasibility of carotid angioplasty and stenting as a possible alternative to CEA. In the tradition of the two previous National Institutes of Health (NIH)-sponsored trials--the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Asymptomatic Carotid Atherosclerosis Study (ACAS)--the National Institutes of Health has sponsored a clinical trial (CREST: Carotid Revascularization-Endarterectomy vs Stent Trial) that is currently under way to determine the efficacy and risks of carotid angioplasty and stenting compared with CEA. 相似文献
33.
Kui Zeng Ilan Geerlof-Vidavisky Ashley Gucinski Xiaohui Jiang Michael T. Boyne II 《The AAPS journal》2015,17(3):643-651
A liquid chromatography-high resolution mass spectrometry (LC-HRMS) method was developed using three peptide drugs: salmon calcitonin, bivalirudin, and exenatide as model systems to assess the suitability of this approach for monitoring peptide drug product quality. Calcitonin and its related impurities displayed linear responses over the range from 0.1 to 10 μM (R2 values for calcitonin salmon, Glu14-calcitonin, and acetyl-calcitonin were 0.995, 0.996, and 0.993, respectively). Intra-assay precision in terms of relative standard deviation (%RSD) was less than 10% at all tested concentrations. The accuracy of the method was greater than 85% as measured by spiking 0.1, 0.3, and 1% of Glu14-calcitonin and acetyl-calcitonin into a stock calcitonin solution. Limits of detection for calcitonin, Glu14-calcitonin, and acetyl-calcitonin were 0.02, 0.03, and 0.04 μM, respectively, indicating that an impurity present at less than 0.1% (0.1 μM) of the drug product API concentration (107 μM) could be detected. Method validation studies analyzing bivalirudin and exenatide drug products exhibited similar results to calcitonin salmon in regard to high selectivity, sensitivity, precision, and linearity. Added benefits of using LC-HRMS-based methods are the ability to also determine amino acid composition, confirm peptide sequence, and quantify impurities, even when they are co-eluting, within a single experiment. LC-HRMS represents a promising approach for the quality control of peptides including the measurement of any peptide-related impurities. While the development work performed here is focus on peptide drug products, the principles could be adapted to peptide drug substance.KEY WORDS: High resolution mass spectrometry, impurity profiling, LC-HRMS, peptide drug 相似文献
34.
35.
Mudrakola Harsha V. Caples Sean M. Hyde Robert J. McBane II Robert D. Ahmad Sumera R. 《Journal of thrombosis and thrombolysis》2022,54(1):145-152
Journal of Thrombosis and Thrombolysis - The optimal management strategy for submassive or intermediate risk pulmonary embolism (IRPE)—anticoagulation alone versus anticoagulation plus... 相似文献
36.
Dong Won Park Jae Young Moon Eun Yong Ku Sun Jong Kim Young-Mo Koo Ock-Joo Kim Soon Haeng Lee Min-Woo Jo Chae-Man Lim John David Armstrong II Younsuck Koh 《Journal of Korean medical science》2015,30(4):495-501
This research aimed to investigate the changes in ethical issues in everyday clinical practice recognized by critical care nurses during two observation periods. We conducted a retrospective analysis of data obtained by prospective questionnaire surveys of nurses in the intensive care units (ICU) of a tertiary university-affiliated hospital in Seoul, Korea. Data were collected prospectively during two different periods, February 2002-January 2003 (Period 1) and August 2011-July 2012 (Period 2). Significantly fewer cases with ethical issues were reported in Period 2 than in Period 1 (89 cases [2.1%] of 4,291 ICU admissions vs. 51 [0.5%] of 9,302 ICU admissions, respectively; P < 0.001). The highest incidence of cases with identified ethical issues in both Periods occurred in MICU. The major source of ethical issues in Periods 1 and 2 was behavior-related. Among behaviorrelated issues, inappropriate healthcare professional behavior was predominant in both periods and mainly involved resident physicians. Ethical issue numbers regarding end-oflife (EOL) care significantly decreased in the proportion with respect to ethical issues during Period 2 (P = 0.044). In conclusion, the decreased incidence of cases with identified ethical issues in Period 2 might be associated with ethical enhancement related with EOL and improvements in the ICU care environment of the studied hospital. However, behaviorrelated issues involving resident physicians represent a considerable proportion of ethical issues encountered by critical care nurses. A systemic approach to solve behavior-related issues of resident physicians seems to be required to enhance an ethical environment in the studied ICU.
Graphical Abstract
相似文献37.
Drew D. DAngelo Yoshihito Sakata John N. Lorenz Gregory P. Boivin Richard A. Walsh Stephen B. Liggett Gerald W. Dorn II 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(15):8121-8126
The critical cell signals that trigger cardiac hypertrophy and regulate the transition to heart failure are not known. To determine the role of Gαq-mediated signaling pathways in these events, transgenic mice were constructed that overexpressed wild-type Gαq in the heart using the α-myosin heavy chain promoter. Two-fold overexpression of Gαq showed no detectable effects, whereas 4-fold overexpression resulted in increased heart weight and myocyte size along with marked increases in atrial naturietic factor (≈55-fold), β-myosin heavy chain (≈8-fold), and α-skeletal actin (≈8-fold) expression, and decreased (≈3-fold) β-adrenergic receptor-stimulated adenylyl cyclase activity. All of these signals have been considered markers of hypertrophy or failure in other experimental systems or human heart failure. Echocardiography and in vivo cardiac hemodynamic studies indeed revealed impaired intrinsic contractility manifested as decreased fractional shortening (19 ± 2% vs. 41 ± 3%), dP/dt max, a negative force–frequency response, an altered Starling relationship, and blunted contractile responses to the β-adrenergic agonist dobutamine. At higher levels of Gαq overexpression, frank cardiac decompensation occurred in 3 of 6 animals with development of biventricular failure, pulmonary congestion, and death. The element within the pathway that appeared to be critical for these events was activation of protein kinase C. Interestingly, mitogen-activated protein kinase, which is postulated by some to be important in the hypertrophy program, was not activated. The Gαq overexpressor exhibits a biochemical and physiologic phenotype resembling both the compensated and decompensated phases of human cardiac hypertrophy and suggests a common mechanism for their pathogenesis. 相似文献
38.
Promoting Resilience Following Traumatic Brain Injury: Application of an Interdisciplinary,Evidence‐Based Model for Intervention 下载免费PDF全文
With an increasing instance of traumatic brain injury and little advancement over recent decades in the rehabilitation of brain injury survivors and their family members, focus has shifted toward the establishment of effective whole‐family resilience promotion interventions. Using the Brain Injury Family Intervention as a model, clinicians constructed two curriculum‐based interventions grounded in resilience theory and drawing from the interdisciplinary approaches of neuropsychology and marriage and family therapy: (a) the Resilience and Adjustment Intervention, for individual survivors of traumatic brain jury, and (b) the Therapeutic Couples Intervention, designed to increase relational satisfaction in couples following a traumatic brain injury. The present study outlines the need for the integration of resilience tenets into rehabilitation techniques, summarizes the empirical justification for the use of an interdisciplinary approach, and offers an overview with implementation specifics regarding these two newly designed interventions. 相似文献
39.
Lisa M. Kuhns Soyang Kwon Daniel T. Ryan Robert Garofalo Gregory Phillips II Brian S. Mustanski 《Journal of urban health》2015,92(1):151-167
Evidence suggests that respondent-driven sampling (RDS) is an efficient approach to sampling among varied populations of adult men who have sex with men (MSM) both in the USA and abroad, although no studies have yet evaluated its performance among younger MSM, a population with a steep rise in HIV infection in recent years. Young MSM (YMSM) may differ in terms of their connectedness to other YMSM (e.g., due to evolving sexual identity, internalization of sexual minority stigma, and lack of disclosure to others) and mobility (e.g., due to parental monitoring) which may inhibit the sampling process. The aims of this study were to evaluate the efficiency and effectiveness of RDS-based sampling among young urban MSM and to identify factors associated with recruitment success. We hypothesized that demographic, social, behavioral, and network factors, including racial/ethnic minority status, homelessness (i.e., as an indicator of socioeconomic marginalization), HIV-positive status, substance use problems, gay community connectedness, and network size would be positively related to recruitment productivity, while sexual minority stigmatization, environmental barriers (e.g., parental monitoring), and meeting sex partners on the internet (i.e., virtual venue) would be negatively related to recruitment productivity. Between December 2009 and February 2013, we used RDS to recruit a sample of 450 YMSM, ages 16–20. Findings suggest that the use of RDS for sampling among YMSM is challenging and may not be feasible based on the slow pace of recruitment and low recruitment productivity. A large number of seeds (38 % of the sample, n = 172) had to be added to the sample to maintain a reasonable pace of recruitment, which makes use of the sample for RDS-based population estimates questionable. In addition, the prevalence of short recruitment chains and segmentation in patterns of recruitment by race/ethnicity further hamper the network recruitment process. Thus, RDS was not particularly efficient in terms of the rate of recruitment or effective in generating a representative sample. Hypotheses regarding factors associated with recruitment success were supported for network size and internalized stigma (but not other factors), suggesting that participants with larger network sizes or high levels of internalized stigma may have more and less success recruiting others, respectively. 相似文献
40.
Megakaryocytic colony formation by progenitor cells of 18 patients with polycythaemia vera, seven with secondary erythrocytosis and four with erythrocytosis of unexplained origin was studied in vitro by the methyl cellulose culture assay. Fourteen of the 18 patients with polycythaemia vera showed spontaneous megakaryocytic colony formation, i.e. colony growth with normal human plasma as the only source of colony stimulation. None of the patients with secondary erythrocytosis or erythrocytosis of unknown origin or of the normal controls grew colonies in the presence of normal human plasma only. When the plasma of a patient with aplastic anaemia was used instead of normal human plasma and phytohaemagglutinin stimulated leucocyte conditioned medium (PHA-LCM) was added to the culture medium, two of the patients with polycythaemia vera and one with secondary erythrocytosis formed slightly increased numbers of megakaryocytic colonies, while the rest of the patients showed normal colony formation. All of the patients with polycythaemia vera but none of those with secondary erythrocytosis or erythrocytosis of unknown origin showed spontaneous erythroid colony growth. The present study shows that most patients with polycythaemia vera form spontaneous megakaryocytic colonies in vitro. This phenomenon has recently also been demonstrated in essential thrombocythaemia and it is apparently analogous to spontaneous erythroid colony growth seen in all myeloproliferative disorders. 相似文献