全文获取类型
收费全文 | 9233篇 |
免费 | 757篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 59篇 |
儿科学 | 201篇 |
妇产科学 | 406篇 |
基础医学 | 1130篇 |
口腔科学 | 148篇 |
临床医学 | 1063篇 |
内科学 | 1890篇 |
皮肤病学 | 113篇 |
神经病学 | 983篇 |
特种医学 | 372篇 |
外科学 | 1065篇 |
综合类 | 155篇 |
一般理论 | 7篇 |
预防医学 | 851篇 |
眼科学 | 228篇 |
药学 | 557篇 |
中国医学 | 63篇 |
肿瘤学 | 765篇 |
出版年
2023年 | 69篇 |
2022年 | 96篇 |
2021年 | 218篇 |
2020年 | 129篇 |
2019年 | 257篇 |
2018年 | 319篇 |
2017年 | 232篇 |
2016年 | 244篇 |
2015年 | 291篇 |
2014年 | 389篇 |
2013年 | 518篇 |
2012年 | 645篇 |
2011年 | 666篇 |
2010年 | 404篇 |
2009年 | 372篇 |
2008年 | 516篇 |
2007年 | 522篇 |
2006年 | 557篇 |
2005年 | 490篇 |
2004年 | 447篇 |
2003年 | 431篇 |
2002年 | 356篇 |
2001年 | 187篇 |
2000年 | 160篇 |
1999年 | 154篇 |
1998年 | 79篇 |
1997年 | 75篇 |
1996年 | 69篇 |
1995年 | 52篇 |
1994年 | 60篇 |
1993年 | 56篇 |
1992年 | 87篇 |
1991年 | 83篇 |
1990年 | 67篇 |
1989年 | 70篇 |
1988年 | 47篇 |
1987年 | 46篇 |
1986年 | 54篇 |
1985年 | 49篇 |
1984年 | 45篇 |
1983年 | 46篇 |
1982年 | 35篇 |
1981年 | 33篇 |
1980年 | 21篇 |
1979年 | 31篇 |
1978年 | 31篇 |
1975年 | 24篇 |
1974年 | 38篇 |
1973年 | 29篇 |
1972年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
Andreas M. Hingsammer Sarah Bixby David Zurakowski Yi-Meng Yen Young-Jo Kim 《Clinical orthopaedics and related research》2015,473(4):1224-1233
BackgroundNormal changes in acetabular version over the course of skeletal development have not been well characterized. Knowledge of normal version development is important because acetabular retroversion has been implicated in several pathologic hip processes.Questions/purposesThe purpose of this study was to characterize the orientation of the acetabulum by measuring (1) acetabular version and (2) acetabular sector angles in pediatric patients during development. We also sought to determine whether these parameters vary by sex in the developing child.MethodsWe evaluated CT images of 200 hips in 100 asymptomatic pediatric patients (45 boys, 55 girls; mean age, 13.5 years; range, 9–18 years) stratified by the status of the triradiate physis and sex. We determined the acetabular anteversion angle at various levels in the axial plane as well as acetabular sector angles at five radial planes around the acetabulum.ResultsFor both genders, anteversion angle was greater for the closed physis group throughout all levels (p < 0.001) and both open and closed physis groups were more anteverted as the cut moved caudally away from the acetabular roof (p < 0.001). At the center of the femoral head, the mean anteversion angle (± SD) in girls was 15° ± 3° in the open group and 19° ± 5° in the closed group (p < 0.001). In boys, the mean anteversion angle increased from 14° ± 4° in the open group to 19° ± 4° in the closed group (p = 0.003). In the superior, posterosuperior, and posterior planes, the acetabular sector angles were greater in the closed compared with the open physis group for both boys and girls with the largest increase occurring in the male posterosuperior plane (approximately 20°) (all p < 0.05).ConclusionsThis study demonstrates that acetabular anteversion and acetabular sector angles in both male and female subjects increase with skeletal maturity as a result of growth of the posterior wall. This suggests that radiographic appearance of acetabular retroversion may not be attributable to overgrowth of the anterior wall but rather insufficient growth of the posterior wall, which has clinical treatment implications for pincer-type impingement.
Level of Evidence
Level IV diagnostic study. 相似文献133.
Eisenman DP Meredith LS Rhodes H Green BL Kaltman S Cassells A Tobin JN 《Journal of general internal medicine》2008,23(9):1386-1392
Background Little is known about how Latinos with post-traumatic stress disorder (PTSD) understand their illness and their preferences
for mental health treatment.
Objective To understand the illness beliefs and treatment preferences of Latino immigrants with PTSD.
Design Semi-structured, face-to-face interviews.
Participants Sixty foreign-born, Latino adults recruited from five primary care centers in New York and New Jersey and screened for PTSD.
Approach Content analytic methods identified common themes, their range, and most frequent or typical responses.
Results Participants identified their primary feelings as sadness, anxiety, nervousness, and fear. The most common feeling was “sad”
(triste). Other words frequently volunteered were “angry” (enojada), “nervous” (nerviosa), and “scared” (miedo). Participants viewed their PTSD as impairing health and functioning. They ascribed their somatic symptoms and their general
medical problems to the “stress” from the trauma and its consequences on their lives. The most common reason participants
volunteered for their work and school functioning being impaired was their poor concentration, often due to intrusive thoughts.
Most expressed their desire to receive mental health treatment, to receive it within their primary care center, and preferred
psychotherapy over psychotropic medications. Among participants who did not report wanting treatment, most said it was because
the trauma was “in the past.”
Conclusions Clinicians may consider enquiring about PTSD in Latino patients who report feeling sad, anxious, nervous, or fearful. Our
study suggests topics clinicians may include in the psychoeducation of patients with PTSD. 相似文献
134.
B Kessel K D Dahl R R Kazer C H Liu J Rivier W Vale A J Hsueh S S Yen 《The Journal of clinical endocrinology and metabolism》1988,66(2):361-366
An antagonist analog of GnRH, (Ac-delta 3-Pro1,p-F-D-Phe2,D-Trp3,6)GnRH (4F-antagonist), was administered to normal women and women with hypergonadotropic hypogonadism. Serum FSH levels were determined by both the granulosa cell aromatase bioassay and RIA. The constant infusion of 4F-antagonist (30 micrograms/kg.h) to the four hypogonadal women resulted in a more pronounced decline in bioactive FSH (62%) than in immunoreactive FSH levels (30%), and the FSH bioactive to immunoreactive ratio decreased significantly (P less than 0.05). Infusion of 4F-antagonist in normal women in the midfollicular phase revealed a similar pattern of suppression of bioactive (64%) and immunoreactive FSH (29%). When 4F-antagonist was administered sc at a dose of 80 micrograms/kg twice daily for 3 days to normal women in the midfollicular phase of their cycles, the bioactive FSH response was biphasic, with the maximal decrease on the second day, followed by return to basal levels on the third day. Correspondingly, there was a precipitous decline in serum estradiol (apparent demise of the dominant follicle), followed by a progressive rise in estradiol levels. Thus, in contrast to immunoreactive FSH levels, bioactive FSH more clearly reflects the biological action of FSH on the follicle in response to GnRH antagonist administration in women. The disparity in the quantitative decline between serum bioactive and immunoreactive FSH levels after presumed blockade of the GnRH receptor may reflect the microheterogeneity of the FSH molecule and suggests that alterations in the biological activity of secreted FSH may be GnRH dependent. 相似文献
135.
Tze Peng Lim Rick Twee-Hee Ong Pei-Yun Hon Jane Hawkey Kathryn E. Holt Tse Hsien Koh Micky Lo-Ngah Leong Jocelyn Qi-Min Teo Thean Yen Tan Mary Mah-Lee Ng Li Yang Hsu 《Antimicrobial agents and chemotherapy》2015,59(12):7899-7902
We studied polymyxin B resistance in 10 pairs of clinical Acinetobacter baumannii isolates, two of which had developed polymyxin B resistance in vivo. All polymyxin B-resistant isolates had lower growth rates than and substitution mutations in the lpx or pmrB gene compared to their parent isolates. There were significant differences in terms of antibiotic susceptibility and genetic determinants of resistance in A. baumannii isolates that had developed polymyxin B resistance in vivo compared to isolates that had developed polymyxin B resistance in vitro. 相似文献
136.
Hiroko P. Indo Hsiu-Chuan Yen Ikuo Nakanishi Ken-ichiro Matsumoto Masato Tamura Yumiko Nagano Hirofumi Matsui Oleg Gusev Richard Cornette Takashi Okuda Yukiko Minamiyama Hiroshi Ichikawa Shigeaki Suenaga Misato Oki Tsuyoshi Sato Toshihiko Ozawa Daret K. St. Clair Hideyuki J. Majima 《Journal of Clinical Biochemistry and Nutrition》2015,56(1):1-7
Fridovich identified CuZnSOD in 1969 and manganese superoxide dismutase (MnSOD) in 1973, and proposed ”the Superoxide Theory,” which postulates that superoxide (O2•−) is the origin of most reactive oxygen species (ROS) and that it undergoes a chain reaction in a cell, playing a central role in the ROS producing system. Increased oxidative stress on an organism causes damage to cells, the smallest constituent unit of an organism, which can lead to the onset of a variety of chronic diseases, such as Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis and other neurological diseases caused by abnormalities in biological defenses or increased intracellular reactive oxygen levels. Oxidative stress also plays a role in aging. Antioxidant systems, including non-enzyme low-molecular-weight antioxidants (such as, vitamins A, C and E, polyphenols, glutathione, and coenzyme Q10) and antioxidant enzymes, fight against oxidants in cells. Superoxide is considered to be a major factor in oxidant toxicity, and mitochondrial MnSOD enzymes constitute an essential defense against superoxide. Mitochondria are the major source of superoxide. The reaction of superoxide generated from mitochondria with nitric oxide is faster than SOD catalyzed reaction, and produces peroxynitrite. Thus, based on research conducted after Fridovich’s seminal studies, we now propose a modified superoxide theory; i.e., superoxide is the origin of reactive oxygen and nitrogen species (RONS) and, as such, causes various redox related diseases and aging. 相似文献
137.
138.
Hilary Bertisch Claire Z. Kalpakjian Pamela A. Kisala David S. Tulsky 《The journal of spinal cord medicine》2015,38(3):356-365
ObjectiveTo develop an item response theory (IRT)-calibrated spinal cord injury (SCI)-specific Positive Affect and Well-being (PAWB) item bank with flexible options for administration.DesignQualitative feedback from patient and provider focus groups was used to expand on the Neurological Disorders and Quality of Life (Neuro-QOL) positive affect & well-being item bank for use in SCI. New items were created and revised based on expert review and patient feedback and were then field tested. Analyses included confirmatory factor analysis, graded response IRT modeling and evaluation of differential item functioning (DIF).SettingWe tested a 32-item pool at several rehabilitation centers across the United States, including the University of Michigan, Kessler Foundation, Rehabilitation Institute of Chicago, the University of Washington, Craig Hospital and the James J. Peters/Bronx Department of Veterans Affairs hospital.ParticipantsA total of 717 individuals with SCI answered the PAWB questions.ResultsA unidimensional model was observed (Confirmatory Fit Index = 0.947; Root Mean Square Error of Approximation = 0.094) and measurement precision was good (reliability in theta of –2.9 to 1.2 is roughly equivalent to classical reliability of 0.95 or above). Twelve items were flagged for DIF, however, after examination of effect sizes, the DIF was determined to be negligible and would have little practical impact on score estimates. The final calibrated item bank resulted in 28 retained itemsConclusionsThis study indicates that the Spinal Cord Injury – Quality of Life PAWB bank represents a psychometrically robust measurement tool. Short form items are also suggested and a computer adaptive test is available. 相似文献
139.
140.
Yung-Pin Lin Li-Yun Lin Hsiang-Yu Yeh Cheng-Hung Chuang Sheng-Wen Tseng Yue-Horng Yen 《Yao wu shi pin fen xi = Journal of food and drug analysis.》2016,24(3):516
Allium chinense is a medicinal plant and nutritional food commonly used in Eastern Asia. In this study, we investigated the in vitro antioxidant activity (scavenging of α,α-diphenyl-β-picrylhydrazyl free radical, total phenol content, reducing power, and total antioxidant activity) and constituents of various extracts from A. chinense. Moreover, we also studied the in vivo hypolipidemic effects of extracts on high-fat-diet Wistar rats. Ethanol extracts from A. chinense showed notable antioxidant activity, and its high-dose essential-oil extract both significantly reduced serum and hepatic total cholesterol, triglyceride, and low-density lipoprotein levels and increased serum high-density lipoprotein levels in high-fat-diet Wistar rats compared with those observed following treatment with the control drug probucol. Additionally, visceral fat in high-fat-diet Wistar rats was reduced. Furthermore, groups with high doses of essential-oil and residue extracts showed protective effects associated with histopathological liver alteration. These results suggested that A. chinense is a valuable plant worthy of further investigation as a potential dietary supplement or botanical drug. 相似文献