全文获取类型
收费全文 | 22315篇 |
免费 | 1792篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 280篇 |
儿科学 | 731篇 |
妇产科学 | 555篇 |
基础医学 | 3088篇 |
口腔科学 | 567篇 |
临床医学 | 2119篇 |
内科学 | 3990篇 |
皮肤病学 | 214篇 |
神经病学 | 2636篇 |
特种医学 | 733篇 |
外科学 | 2686篇 |
综合类 | 461篇 |
一般理论 | 56篇 |
预防医学 | 2198篇 |
眼科学 | 550篇 |
药学 | 1705篇 |
中国医学 | 32篇 |
肿瘤学 | 1558篇 |
出版年
2021年 | 228篇 |
2020年 | 170篇 |
2019年 | 278篇 |
2018年 | 342篇 |
2017年 | 291篇 |
2016年 | 280篇 |
2015年 | 326篇 |
2014年 | 501篇 |
2013年 | 810篇 |
2012年 | 1082篇 |
2011年 | 1149篇 |
2010年 | 652篇 |
2009年 | 605篇 |
2008年 | 1187篇 |
2007年 | 1264篇 |
2006年 | 1227篇 |
2005年 | 1280篇 |
2004年 | 1273篇 |
2003年 | 1248篇 |
2002年 | 1268篇 |
2001年 | 488篇 |
2000年 | 446篇 |
1999年 | 440篇 |
1998年 | 292篇 |
1997年 | 255篇 |
1996年 | 282篇 |
1995年 | 220篇 |
1994年 | 204篇 |
1993年 | 240篇 |
1992年 | 370篇 |
1991年 | 366篇 |
1990年 | 338篇 |
1989年 | 341篇 |
1988年 | 299篇 |
1987年 | 304篇 |
1986年 | 292篇 |
1985年 | 286篇 |
1984年 | 300篇 |
1983年 | 278篇 |
1982年 | 224篇 |
1981年 | 216篇 |
1980年 | 167篇 |
1979年 | 230篇 |
1978年 | 173篇 |
1977年 | 135篇 |
1976年 | 141篇 |
1975年 | 118篇 |
1974年 | 131篇 |
1973年 | 113篇 |
1972年 | 114篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
22.
Anthony Spirito Larry Brown James Overholser Gregory Fritz Andrea Bond 《Death Studies》1991,15(3):269-280
The assessment of the medical lethality and intent of suicide attempts has been considered an important area of research for those interested in suicide. The current study examined the usefulness of the Risk-Rescue Rating Scale with 109 adolescent suicide attempters and found a restricted range of variability, which, in turn, resulted in poor interrater reliability on a number of items. Results suggest that the Risk-Rescue Rating Scale is of limited usefulness with adolescents, and alternative approaches to assessing lethality and suicidal intent with this age group are discussed. 相似文献
23.
Potential digestibility and rate of degradation of water-insoluble material (WIM) prepared from rutabaga, wheat bran and digesta recovered from the terminal ileum of pigs fed bran- or rutabaga-based diets were measured in the cecum of surgically modified pigs. WIM samples recovered from the cecum after fixed incubation times were analyzed and the rate of total disappearance of organic matter, cellulose, uronic acid and noncellulosic neutral sugars was calculated. Maximum degradation of each WIM occurred within 48 h after incubation and was for rutabaga and its ileal digesta 90 and 70%, respectively, and for bran and bran ileal digesta 55 and 45%, respectively. Cellulose and uronic acid in bran samples did not appear to be degraded, material disappearance being attributable to the loss of noncellulosic neutral sugars. Estimation of potential organic matter digestibility showed rutabaga to be 93%, rutabaga digesta 79%, bran 56% and bran digesta 43% digestible. Fractional rates of digestion in rutabaga samples were significantly faster than in corresponding bran samples. When related to the role of fiber in nutrition the results obtained suggest that cereal fiber would be only slightly modified during gut transit, unlike vegetable fiber in which microbial digestion would probably result in the total destruction of the fiber cell wall matrix. 相似文献
24.
We examined several possible causes for the high incidence of poor sensory acuity in the limbs of 176 patients with moderate to severe peripheral vascular insufficiency. We investigated the relationships of diabetes, alcoholism, and smoking, as well as the severity of peripheral vascular disease, to the integrity of basic sensory modalities such as two-point discrimination and perception of light touch. The presence or absence of diabetes exerted the strongest effect on peripheral sensation. In patients who did not have diabetes, sensation in the limbs was most strongly affected by whether the patient was an alcoholic. Smoking did not have a significant effect on limb sensation. Among nondiabetic, nonalcoholic patients, there was a weak residual effect related to the severity of the peripheral vascular insufficiency. Even among these patients, however, systemic factors predominated in determining the loss of sensation. We also examined the extent to which loss of sensation might be related to the development of ulcers. Among patients who were not diabetic, there was a highly significant relationship between loss of sensation and the presence of limb ulceration. Surprisingly, however, there was no discernable relationship between the presence of ulcers in diabetic patients and the degree of loss of peripheral sensation. This result suggests that a large percentage of ulcers seen in diabetic patients are not of neurogenic origin. 相似文献
25.
26.
Ruhangiz T. Kilani ; Larry Guilbert ; Xiaoyue Lin ; Aziz Ghahary 《Wound repair and regeneration》2007,15(2):236-244
Overexpression of wound healing-promoting factors such as transforming growth factor-1 (TGF-beta1) and insulin-like growth factor-1 (IGF-1) during the healing process has been implicated in the development of dermal fibrosis in patients following thermal injury, surgical incision, and deep trauma. However, the mechanism through which the expression of these two fibrogenic factors is slowed down and/or abrogated in the late stages of the healing process is not known. Here, we hypothesize that keratinocyte-releasable factors counteract the fibrogenic role of both IGF-1 and TGF-beta1 in fibroblasts. To test this hypothesis, the levels of collagenase (MMP-1), as an index for extracellular matrix degradation, in dermal fibroblasts in response to either keratinocyte-conditioned medium (KCM) or our recently identified keratinocyte-releasable stratifin in the presence and absence of either IGF-1, TGF-beta1, or both were evaluated. The results of Northern analysis showed a significant increase in collagenase mRNA expression in cells treated with KCM in the presence of both IGF-1 and TGF-beta1. The effect was, at least in part, due to keratinocyte-derived stratifin that was present in KCM. This was ascertained as the levels of MMP-1 mRNA were markedly reduced when cells were treated with stratifin-immuno-depleted KCM. The results of Western blot analysis showed an increase in the level of MMP-1 protein in stratifin-treated fibroblasts and this was consistent with the level of MMP-1 mRNA expression detected by Northern analysis. However, in contrast to KCM, whose efficacy on MMP-1 expression was modestly reduced by either IGF-1 and TGF-beta1, or a combination of both, these factors abrogated the MMP-1 stimulatory effect of stratifin in fibroblasts. In summary, the results of this study revealed that both stratifin and KCM stimulate the expression of MMP-1-in fibroblasts and this effect can be abrogated by either IGF-1, TGF-beta1, or a combination of both. 相似文献
27.
Donna K. McNeese-Smith Mary E. Wickman Marie Earvolino-Ramirez Mel Moncrieff Scott Robertson 《Journal of addictions nursing》2006,17(2):105-113
This article reports the results of semi-structured interviews with substance abuse treatment (SAT) program directors (PDs) regarding the ways SAT is being influenced by managed care (MC), plans for future SAT, and strategies for decreasing costs of care. It compares findings to an earlier survey of 50 SAT PDs.
Interviews were conducted in 20 SAT programs to gather information about treatment delivery since the advent of MC, including PD responsibilities, funding source, treatment intensity, location, duration, and methods of treatment. Open-ended responses were used to gather information about current and future plans in providing SAT, and awareness of new types of treatment being planned by organizations impacted by MC.
PDs reported changes in SAT secondary to MC such as decreased treatment length, limiting of inpatient and outpatient services, and delayed treatment secondary to benefit determination. Political and economic constraints were seen as barriers to providing adequate and effective services. SAT being subsumed by mental health was viewed as problematic along with an emerging split between alcohol abuse and drug treatment. A positive emerging treatment trend was the development of targeted programs for special need groups.
PDs revealed a variety of strategies that have promoted necessary adaptations to economic and political influences within the structure of managed behavioral care. Strategies such as varying treatment length, modality, and subspecialty care reflected necessary adaptations to diverse market needs.
Managed care continues to have a tremendous impact on the delivery of SAT services. While MC has helped to contain costs, negative outcomes are decreased availability of appropriate care and overtaxing of units that have survived MC cut backs. However, special need programs have allowed SAT programs to specialize, expand, and even flourish in today's competitive SAT market. Interviews with PDs reinforced the need for maintaining quality and diversified SAT services in today's MC environment. 相似文献
Interviews were conducted in 20 SAT programs to gather information about treatment delivery since the advent of MC, including PD responsibilities, funding source, treatment intensity, location, duration, and methods of treatment. Open-ended responses were used to gather information about current and future plans in providing SAT, and awareness of new types of treatment being planned by organizations impacted by MC.
PDs reported changes in SAT secondary to MC such as decreased treatment length, limiting of inpatient and outpatient services, and delayed treatment secondary to benefit determination. Political and economic constraints were seen as barriers to providing adequate and effective services. SAT being subsumed by mental health was viewed as problematic along with an emerging split between alcohol abuse and drug treatment. A positive emerging treatment trend was the development of targeted programs for special need groups.
PDs revealed a variety of strategies that have promoted necessary adaptations to economic and political influences within the structure of managed behavioral care. Strategies such as varying treatment length, modality, and subspecialty care reflected necessary adaptations to diverse market needs.
Managed care continues to have a tremendous impact on the delivery of SAT services. While MC has helped to contain costs, negative outcomes are decreased availability of appropriate care and overtaxing of units that have survived MC cut backs. However, special need programs have allowed SAT programs to specialize, expand, and even flourish in today's competitive SAT market. Interviews with PDs reinforced the need for maintaining quality and diversified SAT services in today's MC environment. 相似文献
28.
29.
Charles H Henry Judith A Whittum-Hudson Gregory T Tull Larry M Wolford 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(1):e22-e26
OBJECTIVE: The objective of this study was to determine if temporomandibular joint (TMJ) samples positive for Chlamydia trachomatis have a greater presence of tumor necrosis factor-alpha (TNFalpha) or interleukin-6 (IL-6) when compared with Chlamydia-negative samples. STUDY DESIGN: Posterior bilaminar tissue samples removed during TMJ surgery from 70 patients were evaluated. Cryosections were stained using monoclonal antibody that identifies C. trachomatis. The presence of IL-6 and TNFalpha were evaluated by immunostaining in 15 samples positive and in 25 samples negative for the presence of C. trachomatis. RESULTS: Of the 70 TMJ samples, 32 (46%) were positive for C. trachomatis. In 15 samples positive for C. trachomatis, 10 (67%) were positive for TNFalpha and 7 (47%) for IL-6. In 25 samples negative for C. trachomatis, only 4 (16%) were positive for TNFalpha and only 2 (8%) for IL-6. Differences in C. trachomatis-positive samples versus negative were significant for both TNFalpha (P < .002) and IL-6 (P < .008). CONCLUSION: The presence of C. trachomatis in the TMJ is associated with a significantly increased presence of TNFalpha and IL-6. 相似文献
30.