全文获取类型
收费全文 | 34454篇 |
免费 | 2413篇 |
国内免费 | 121篇 |
专业分类
耳鼻咽喉 | 255篇 |
儿科学 | 1103篇 |
妇产科学 | 784篇 |
基础医学 | 4662篇 |
口腔科学 | 948篇 |
临床医学 | 3470篇 |
内科学 | 6631篇 |
皮肤病学 | 417篇 |
神经病学 | 3883篇 |
特种医学 | 1286篇 |
外国民族医学 | 6篇 |
外科学 | 4852篇 |
综合类 | 430篇 |
一般理论 | 52篇 |
预防医学 | 2486篇 |
眼科学 | 1187篇 |
药学 | 2435篇 |
中国医学 | 51篇 |
肿瘤学 | 2050篇 |
出版年
2022年 | 197篇 |
2021年 | 458篇 |
2020年 | 280篇 |
2019年 | 458篇 |
2018年 | 556篇 |
2017年 | 463篇 |
2016年 | 506篇 |
2015年 | 567篇 |
2014年 | 794篇 |
2013年 | 1319篇 |
2012年 | 2004篇 |
2011年 | 2204篇 |
2010年 | 1192篇 |
2009年 | 1126篇 |
2008年 | 2122篇 |
2007年 | 2385篇 |
2006年 | 2350篇 |
2005年 | 2351篇 |
2004年 | 2231篇 |
2003年 | 2212篇 |
2002年 | 2107篇 |
2001年 | 366篇 |
2000年 | 316篇 |
1999年 | 375篇 |
1998年 | 484篇 |
1997年 | 433篇 |
1996年 | 340篇 |
1995年 | 356篇 |
1994年 | 341篇 |
1993年 | 327篇 |
1992年 | 322篇 |
1991年 | 286篇 |
1990年 | 267篇 |
1989年 | 218篇 |
1988年 | 212篇 |
1987年 | 201篇 |
1986年 | 237篇 |
1985年 | 229篇 |
1984年 | 345篇 |
1983年 | 311篇 |
1982年 | 372篇 |
1981年 | 325篇 |
1980年 | 349篇 |
1979年 | 213篇 |
1978年 | 231篇 |
1977年 | 232篇 |
1976年 | 166篇 |
1975年 | 166篇 |
1974年 | 158篇 |
1973年 | 125篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
91.
The Speech-Language Pathologist Stress Inventory (SLPSI) is a 48-item questionnaire adapted from the Teacher Stress Inventory (Fimian, 1988). Factor analyses of the responses of 626 speech-language pathologists revealed four stress source factors (Bureaucratic Restrictions, Time and Workload Management, Lack of Professional Supports, and Instructional Limitations) and two stress manifestation factors (Emotional-Fatigue Manifestations and Biobehavioral Manifestations). The internal consistency reliability of scales based on these factors ranged from .71 to .87, with .93 for the entire scale. Evidence for construct validity was found in moderate positive correlations between the scales of the SLPSI and the scales of the Maslach Burnout Inventory (MBI) (Maslach & Jackson, 1986). Stress and burnout subscale intercorrelations ranged from .10 to .82 (p less than .01), and the correlation between stress strength and burnout frequency was .66 (p less than .001). 相似文献
92.
Mark C. K. Yang Ronald G. Marks William B. Clark Ingvar Magnusson 《Journal of clinical periodontology》1992,19(2):77-83
Abstract Several statistical models that have been suggested in the periodontal literature for describing longitudinal attachment level changes, such as the gradual loss, single-burst, multiple-burst, and random walk models as well as other models introduced in this paper are compared by their power to predict future attachment loss. The data used in this analysis is from 1061 sites of 8 subjects, with moderate to severe periodontal disease, monitored monthly for about a year. This study found that none of the suggested models could significantly outperform the naive mean predictor, which predicts the future attachment level from the past mean. It was also found that no single model, such as the burst, gradual, or random walk, together with measurement error can fully explain the variation in the data. These results indicate that in the course of one year, the attachment level change may not follow the same model. Consequently, a model that fits well to past data cannot be accurately extended to the future. 相似文献
93.
94.
Editorial comment 总被引:2,自引:0,他引:2
Ronald Dubner Howard L. Fields Gerald F. Gebhart John D. Loeser Harold Merskey Patrick D. Wall 《Pain》1992,50(3):247-248
95.
Ronald R. Watson PhD Mary E. Mohs MS RD Cteamond Eskelson PhD Richard E. Samptiner MD Barbara Hartmann PhD 《Alcoholism, clinical and experimental research》1986,10(4):364-385
The prevalence and incidence of heavy alcohol consumption are major problems which have been increasing in many countries in recent years. It is crucial for physicians to consistently identify early drinking problems as well as the various end disease states in order to minimize suffering and maximize recovery. This paper reviews the evolutionary development of clinical tools for detection of alcohol abuse. The focus is primarily on clinical/biochemical indicators of alcohol abuse, emphasizing but not limited to changes in hematological characteristics, liver enzyme activity, lipids, immune function factors, hormones, neurological factors, and some physically based tests. Use of test combinations and sophisticated statistical analysis of pattern changes in test batteries evidence increased diagnostic efficiency. 相似文献
96.
Zvi Bar-Shavit Ronald L. Horst Jean C. Chappel F. Patrick Ross Richard W. Gray Steven L. Teitelbaum M.D. 《Calcified tissue international》1986,39(5):328-333
Summary 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is a potent inducer of monocytic differentiation of the human promyelocytic leukemia cell line, HL-60. We have noted that
25-hydroxyvitamin D3 (25(OH)D3) in high doses is also capable of promoting monocytic differentiation of this cell line. To test the possibility that the
latter activity is due to conversion of 25OHD3 to 1,25(OH)2D3 by HL-60, we exposed HL-60 cells to 25OHD3 and analyzed the products by HPLC and radioreceptor assay. When chromatographed in the traditional solvent system (isopropanol-hexane),
a new peak appears which migrates with authentic 1,25(OH)2D3. However, in a solvent system containing dichloromethane, 90% of the peak migrates with another metabolite, 19-Nor-10-Keto-25OHD3 (19-Nor-25OHD3). Production of this metabolite is enhanced by living cells and is synthesized by both virgin HL-60 and those which have
undergone differentiation. We next determined if authentic 19-Nor-25OHD3 also promotes differentiation of this cell. As assessed by appearance of the monocyte-specific surface antigen (63D3) and
macrophage-specific esterase activity, we find that this metabolite does, in fact, induce monocytic differentiation of HL-60
with a potency of approximately 1/200 that of 1,25(OH)2D3 and similar to that of 25OHD3. In agreement with the effect upon cell maturation, 19-Nor-25OHD3 displaces3H-1,25(OH)2D3 from its HL-60 receptor with an efficiency comparable to 25OHD3. Hence, HL-60 cells convert 25OHD3 to 19-Nor-25OHD3, and 19-Nor-25OHD3 induces monocytic differentiation of HL-60 with comparable efficiency to its precursor, 25OHD3. 相似文献
97.
Production of tumor necrosis factor and other cytokines by astrocytes stimulated with lipopolysaccharide or a neurotropic virus. 总被引:39,自引:4,他引:35
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A P Lieberman P M Pitha H S Shin M L Shin 《Proceedings of the National Academy of Sciences of the United States of America》1989,86(16):6348-6352
Rat astrocytes, immunologically competent glial cells of the central nervous system (CNS), released a variety of cytokines after activation. Lipopolysaccharide-stimulated astrocytes produced tumor necrosis factor (TNF) as demonstrated by Northern blot analysis using a mouse TNF probe and by functional assay. Biological activity of rat astrocyte-derived TNF was neutralized by rabbit antiserum against recombinant murine TNF. Stimulation of astrocytes by lipopolysaccharide also activated the interleukin 1 and interleukin 6 genes. We have also investigated whether a neurotropic paramyxovirus, Newcastle disease virus, triggers cytokine production by astrocytes. This virus induced astrocytes to produce TNF, lymphotoxin, interleukin 6, and alpha- and beta-interferons. Thus, stimulation by endotoxin and virus activated distinct, yet overlapping, sets of cytokine genes. We propose that astrocytes and the cytokines they produce may play a significant role in the pathogenesis of immunologically and/or virally mediated CNS disease, in CNS intercellular communication, and in the interactions between the nervous and immune systems. 相似文献
98.
Steven G. E. Marsh Ekkehard D. Albert Walter F. Bodmer Ronald E. Bontrop Bo Dupont Henry A. Erlich Daniel E. Geraghty John A. Hansen Bernard Mach Wolfgang R. Mayr Peter Parham Effie W. Petersdorf Takehiko Sasazuki Geziena M. Th. Schreuder Jack L. Strominger Arne Svejgaard Paul I. Terasaki 《International journal of immunogenetics》2002,29(6):463-515
99.
Ruth Dailey Grainger Clifford Levin Lois Allen-Byrd Ronald M. Doctor Howard Lee 《Journal of traumatic stress》1997,10(4):665-671
Controlled studies of treatments effective with victims of natural disasters are almost nonexistent. This is a small study conducted under difficult conditions to test the effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) in treating trauma related reactions following Hurricane Andrew. The results were positive in that EMDR produced significant improvement over wail list controls in perceived posttraumatic avoidance behaviors and thoughts as measured by changes in the Impact of Event Scale and significant improvement in subjective aversive reactions to representative experiences of the hurricane. These results suggest and support other studies that EMDR can be an effective therapeutic intervention for trauma reactions. 相似文献
100.
M G Conlan W D Haire R P Lieberman G Lund A Kessinger J O Armitage 《Bone marrow transplantation》1991,7(3):235-240
Long-term indwelling central venous catheters have eased the administration of drugs, blood products, and hyperalimentation to patients with cancer. However, their use is associated with thrombotic complications. We report here on the thrombotic complications prospectively observed in 46 patients with refractory lymphoma (22 Hodgkin's disease, 24 non-Hodgkin's lymphoma) who had placement of one or more catheters in preparation for autologous stem cell transplantation (ASCT). Thrombosis of 26 catheters in 19 patients was observed. Specific abnormalities of hemostasis were equally common in patients who developed thrombosis and in those who did not. Thrombotic complications were more common in patients with Hodgkin's disease (13/22) than in patients with non-Hodgkin's lymphoma (6/24, p = 0.04). Although more patients with Hodgkin's disease had received prior splenectomy and/or irradiation to the area involved by thrombosis than patients with non-Hodgkin's lymphoma, the incidence of splenectomy and irradiation was similar for patients with Hodgkin's disease who developed thrombosis and those who did not. Therefore, although the etiology remains unexplained, patients with Hodgkin's disease undergoing intensive chemotherapy and ASCT appear to have a higher incidence of catheter-related thrombosis than patients with non-Hodgkin's lymphoma undergoing similar therapy. 相似文献