全文获取类型
收费全文 | 46913篇 |
免费 | 3497篇 |
国内免费 | 170篇 |
专业分类
耳鼻咽喉 | 703篇 |
儿科学 | 1088篇 |
妇产科学 | 734篇 |
基础医学 | 5806篇 |
口腔科学 | 767篇 |
临床医学 | 5276篇 |
内科学 | 9045篇 |
皮肤病学 | 631篇 |
神经病学 | 4143篇 |
特种医学 | 1810篇 |
外国民族医学 | 2篇 |
外科学 | 8152篇 |
综合类 | 768篇 |
现状与发展 | 1篇 |
一般理论 | 32篇 |
预防医学 | 3725篇 |
眼科学 | 1003篇 |
药学 | 3534篇 |
1篇 | |
中国医学 | 77篇 |
肿瘤学 | 3282篇 |
出版年
2023年 | 308篇 |
2022年 | 469篇 |
2021年 | 1221篇 |
2020年 | 654篇 |
2019年 | 1229篇 |
2018年 | 1443篇 |
2017年 | 1042篇 |
2016年 | 1050篇 |
2015年 | 1285篇 |
2014年 | 1877篇 |
2013年 | 2387篇 |
2012年 | 3626篇 |
2011年 | 3874篇 |
2010年 | 2135篇 |
2009年 | 1792篇 |
2008年 | 3117篇 |
2007年 | 3455篇 |
2006年 | 3259篇 |
2005年 | 3109篇 |
2004年 | 2735篇 |
2003年 | 2716篇 |
2002年 | 2414篇 |
2001年 | 363篇 |
2000年 | 233篇 |
1999年 | 353篇 |
1998年 | 485篇 |
1997年 | 334篇 |
1996年 | 291篇 |
1995年 | 292篇 |
1994年 | 245篇 |
1993年 | 204篇 |
1992年 | 161篇 |
1991年 | 146篇 |
1990年 | 143篇 |
1989年 | 147篇 |
1988年 | 140篇 |
1987年 | 131篇 |
1986年 | 108篇 |
1985年 | 132篇 |
1984年 | 152篇 |
1983年 | 134篇 |
1982年 | 164篇 |
1981年 | 142篇 |
1980年 | 157篇 |
1979年 | 78篇 |
1978年 | 88篇 |
1977年 | 60篇 |
1976年 | 52篇 |
1975年 | 54篇 |
1974年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
961.
962.
Carolyn Y. Fang Brian L. Egleston Kelley Pettee Gabriel Victor J. Stevens Peter O. Kwiterovich Jr. Linda G. Snetselaar Margaret L. Longacre Joanne F. Dorgan 《Journal of behavioral medicine》2013,36(2):143-152
Accumulating data suggest that depression is associated with risk factors for cardiovascular disease, but few studies have investigated potential behavioral mediators of such associations, particularly among women. In this study of healthy young adult women (n = 225), we examined associations among depressive symptoms, health behaviors, and serum lipid levels. Depressive symptoms were assessed with the 20-item Center for Epidemiologic Studies-Depression scale, and a fasting blood sample was obtained for serum lipid levels, including total cholesterol, high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C). Diet was measured using 24-h recalls, and other health behaviors (physical activity, smoking) were assessed via self-report questionnaire. Results indicated a modest negative association between depressive symptoms and LDL-C levels. Higher levels of depressive symptoms were also associated with lower total and insoluble dietary fiber intake, both of which were associated with HDL-C and LDL-C. Mediational analyses indicated a significant indirect effect of depressive symptoms on LDL-C via total and insoluble dietary fiber in unadjusted analyses, but not in adjusted analyses. The present findings suggest that depressive symptoms are inversely associated with serum LDL-C levels in young adult women, but that these associations are not likely mediated by adverse lifestyle behaviors. 相似文献
963.
964.
965.
Marinella Cappelletti Michael Kopelman Brian Butterworth 《Cognitive neuropsychology》2013,30(6):483-503
This paper describes a patient (IH) with semantic dementia and severe impairment in all semantic categories except for numerical knowledge, which was preserved. IH showed a severe deficit in reading and writing non-number words (e.g., candle, juice) and nonwords, and preservation of reading and writing number words (e.g., one, forty) and numerals (e.g., 1, 40). IH's pattern of performance can be explained by the combination of a selective sparing of one semantic category--i.e., numbers--with a total deficit of nonsemantic processes for mapping letters and sounds. As number was the only spared semantic category in the presence of these other nonsemantic deficits, it follows that the semantic route is sufficient for accurate reading and spelling. Our data clarify the nature of reading and writing processes and support the functional and neuroanatomical independence of the number domain. 相似文献
966.
Marinella Cappelletti Michael D. Kopelman John Morton Brian Butterworth 《Cognitive neuropsychology》2013,30(7):771-793
This study describes a 3-year follow-up investigation of the deterioration of number abilities in a semantic dementia patient (IH). A few studies have previously reported the decline of number knowledge in patients with degenerative disorders, although almost never in semantic dementia (Diesfeldt, 1993; Girelli, Luzzatti, Annoni, & Vecchi, 1999; Grafman, Kempen, Rosenberg, Salazar, & Boller, 1989). These studies described the change of the patients’ performance mainly in terms of increased errors in number tasks. On the other hand, dissociations between different types of number abilities, or different arithmetical operations, have been reported in patients with focal lesions. In the present investigation, the cognitive basis of number processing was revealed throughout the patient's cognitive decline. Two major results emerged from a longitudinal study: First, the patient's conceptual knowledge of arithmetic was well preserved despite severe impairment of nonarithmetic conceptual knowledge. Second, the patient's progressive decline revealed patterns of dissociations between different number abilities. These were between (1) multiplication and other arithmetical operations, which particularly emerged in the use of algorithms; (2) impaired knowledge of number facts and procedures on one hand, and conceptual knowledge of arithmetic on the other; and (3) different types of transcoding skills. The implications of these dissociations for the cognitive architecture of number processing are discussed. 相似文献
967.
Eric D. Holbrook Katherine A. Smolnycki Brian H. Youseff Chad A. Rappleye 《Infection and immunity》2013,81(7):2334-2346
Histoplasma capsulatum is a respiratory pathogen that infects phagocytic cells. The mechanisms allowing Histoplasma to overcome toxic reactive oxygen molecules produced by the innate immune system are an integral part of Histoplasma''s ability to survive during infection. To probe the contribution of Histoplasma catalases in oxidative stress defense, we created and analyzed the virulence defects of mutants lacking CatB and CatP, which are responsible for extracellular and intracellular catalase activities, respectively. Both CatB and CatP protected Histoplasma from peroxide challenge in vitro and from antimicrobial reactive oxygen produced by human neutrophils and activated macrophages. Optimal protection required both catalases, as the survival of a double mutant lacking both CatB and CatP was lower than that of single-catalase-deficient cells. Although CatB contributed to reactive oxygen species defenses in vitro, CatB was dispensable for lung infection and extrapulmonary dissemination in vivo. Loss of CatB from a strain also lacking superoxide dismutase (Sod3) did not further reduce the survival of Histoplasma yeasts. Nevertheless, some catalase function was required for pathogenesis since simultaneous loss of both CatB and CatP attenuated Histoplasma virulence in vivo. These results demonstrate that Histoplasma''s dual catalases comprise a system that enables Histoplasma to efficiently overcome the reactive oxygen produced by the innate immune system. 相似文献
968.
969.
Bhupal P. Bhetwal Changlong An Salah A. Baker Kristin L. Lyon Brian A. Perrino 《Journal of muscle research and cell motility》2013,34(2):137-149
Diabetic gastroparesis is a common complication of diabetes, adversely affecting quality of life with symptoms of abdominal discomfort, nausea, and vomiting. The pathogenesis of this complex disorder is not well understood, involving abnormalities in the extrinsic and enteric nervous systems, interstitial cells of Cajal (ICCs), smooth muscles and immune cells. The ob/ob mouse model of obesity and diabetes develops delayed gastric emptying, providing an animal model for investigating how gastric smooth muscle dysfunction contributes to the pathophysiology of diabetic gastroparesis. Although ROCK2, MYPT1, and CPI-17 activities are reduced in intestinal motility disorders, their functioning has not been investigated in diabetic gastroparesis. We hypothesized that reduced expression and phosphorylation of the myosin light chain phosphatase (MLCP) inhibitory proteins MYPT1 and CPI-17 in ob/ob gastric antrum smooth muscles could contribute to the impaired antrum smooth muscle function of diabetic gastroparesis. Spontaneous and carbachol- and high K+-evoked contractions of gastric antrum smooth muscles from 7 to 12 week old male ob/ob mice were reduced compared to age- and strain-matched controls. There were no differences in spontaneous and agonist-evoked intracellular Ca2+ transients and myosin light chain kinase expression. The F-actin:G-actin ratios were similar. Rho kinase 2 (ROCK2) expression was decreased at both ages. Basal and agonist-evoked MYPT1 and myosin light chain 20 phosphorylation, but not CPI-17 phosphorylation, was reduced compared to age-matched controls. These findings suggest that reduced MLCP inhibition due to decreased ROCK2 phosphorylation of MYPT1 in gastric antrum smooth muscles contributes to the antral dysmotility of diabetic gastroparesis. 相似文献
970.
Michael J. Cortese Susan D. Sergent-Marshall Randy L. Buckner Brian T. Gold 《Cognitive neuropsychology》2013,30(6):856-876
Older adults, individuals with dementia of the Alzheimer's type (DAT), and individuals with semantic dementia (SD) produced the past tense of verbs based on present-tense carrier sentences (e.g., Everyday I ding the bell. Yesterday I_____the bell). Both regularity (i.e., whether or not -ed is used for the past tense) and consistency (i.e., the degree to which verbs of similar orthography and phonology in the present tense have similar past tenses to the target) were manipulated. Participants received regular consistent (e.g., land–landed), regular inconsistent (e.g., weed–weeded), irregular consistent (e.g., sting–stung), and irregular inconsistent (e.g., light–lit) verbs. The dependent measures were overall accuracy rates and error rate types (e.g., regularizations, analogies, and other errors). Both consistency and regularity influenced performance. In addition, individuals with DAT showed a disproportionate deficit for inconsistent verbs associated with a high summed frequency of enemies, whereas SD individuals produced disproportionate breakdowns in performance on regular inconsistent, irregular consistent, and irregular inconsistent verbs. These results are consistent with the perspective that semantic/lexical processes are involved in processing the past tense of both irregular verbs and regular inconsistent verbs, and that attention is used to select appropriate responses and control inappropriate responses. 相似文献