全文获取类型
收费全文 | 1808篇 |
免费 | 178篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 105篇 |
妇产科学 | 50篇 |
基础医学 | 240篇 |
口腔科学 | 41篇 |
临床医学 | 220篇 |
内科学 | 354篇 |
皮肤病学 | 32篇 |
神经病学 | 127篇 |
特种医学 | 129篇 |
外科学 | 270篇 |
综合类 | 57篇 |
预防医学 | 112篇 |
眼科学 | 32篇 |
药学 | 96篇 |
中国医学 | 1篇 |
肿瘤学 | 105篇 |
出版年
2020年 | 13篇 |
2019年 | 18篇 |
2018年 | 15篇 |
2017年 | 16篇 |
2016年 | 13篇 |
2015年 | 26篇 |
2014年 | 33篇 |
2013年 | 55篇 |
2012年 | 47篇 |
2011年 | 55篇 |
2010年 | 49篇 |
2009年 | 35篇 |
2008年 | 57篇 |
2007年 | 58篇 |
2006年 | 60篇 |
2005年 | 66篇 |
2004年 | 62篇 |
2003年 | 56篇 |
2002年 | 64篇 |
2001年 | 39篇 |
2000年 | 51篇 |
1999年 | 64篇 |
1998年 | 34篇 |
1997年 | 51篇 |
1996年 | 45篇 |
1995年 | 28篇 |
1994年 | 38篇 |
1993年 | 36篇 |
1992年 | 67篇 |
1991年 | 56篇 |
1990年 | 63篇 |
1989年 | 74篇 |
1988年 | 49篇 |
1987年 | 41篇 |
1986年 | 54篇 |
1985年 | 35篇 |
1984年 | 37篇 |
1983年 | 32篇 |
1982年 | 23篇 |
1981年 | 16篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1978年 | 20篇 |
1977年 | 18篇 |
1974年 | 15篇 |
1973年 | 14篇 |
1972年 | 18篇 |
1971年 | 14篇 |
1967年 | 12篇 |
1945年 | 13篇 |
排序方式: 共有1986条查询结果,搜索用时 15 毫秒
1.
J P Dutcher C E Riggs J J Strauman B Link P H Wiernik 《Clinical pharmacology and therapeutics》1989,45(4):424-428
In a phase I-II study, 21 patients with relapsed or refractory acute leukemia were treated with 4'-deoxydoxorubicin (esorubicin), the 4'-deoxy derivative of doxorubicin. Four of 14 evaluable patients with acute nonlymphocytic leukemia (ANLL) in relapse or refractory to other anthracyclines achieved partial response (28.5%). Pharmacokinetics were similar to those of the parent compound, doxorubicin. Esorubicin has activity in ANLL and has pharmacologic properties comparable to those of other anthracyclines. Dose-limiting toxicity occurs in the form of mucositis, which may limit its use in combination with other antileukemic drugs. 相似文献
2.
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章. 相似文献
3.
4.
Effect of blockade of TNF-alpha and interleukin-1 action on bone resorption in early postmenopausal women. 总被引:1,自引:0,他引:1
Natthinee Charatcharoenwitthaya Sundeep Khosla Elizabeth J Atkinson Louise K McCready B Lawrence Riggs 《Journal of bone and mineral research》2007,22(5):724-729
After acute estrogen withdrawal in postmenopausal women, administration of anakinra or etanercept, specific blockers of IL-1 and TNF-alpha, respectively, reduced the rise in bone resorption markers to about one half of that in controls. This is consistent with an important role for these immune cytokines in mediating the effect of estrogen deficiency on bone. INTRODUCTION: Studies in rodents have implicated increased production of interleukin (IL)-1 beta and TNF-alpha as mediators of bone loss after ovariectomy, but their roles are unclear in humans whose immune system differs markedly from that of rodents. MATERIALS AND METHODS: We administered transdermal estradiol, 0.1 mg/d, for 60 days to 42 early postmenopausal women. Estrogen treatment was discontinued, and subjects were randomly assigned to intervention groups receiving 3 wk of injections with 0.9% saline, anakinra 100 mg/d, or etanercept 25 mg/twice weekly. Bone turnover was assessed by measuring serum carboxyl-terminal telopeptide of type 1 collagen (CTX) and amino-terminal telopeptide of type 1 collagen (NTX), markers for bone resorption, and serum amino-terminal propeptide of type 1 collagen (P1NP), a marker for bone formation. Results were expressed as percent change in markers from baseline (last 2 days of estrogen treatment and days 20 and 21 of intervention). RESULTS: The percent changes from baseline during intervention for serum CTX, urine NTX, and serum PINP, respectively, were 43.3 +/- 8.0%, 12.0 +/- 7.1%, and -41.0 +/- 2.5% for the control group; 25.9 +/- 6.3%, 9.5 +/- 4.0%, and -37.8 +/- 3.0% for the anakinra group; and 21.7 +/- 5.0%, 0.32 +/- 3.82%, and -34.5 +/- 3.9% for the etanercept group. Compared with the control group, the blunting of the increase in serum CTX fell just below the level of significance (p=0.10) after anakinra treatment, whereas the blunting of the increase in serum CTX (p=0.034) and in urine NTX (p=0.048) were significant after etanercept treatment. Other changes were not significant. CONCLUSIONS: The data are consistent with a role for TNF-alpha, and possibly for IL-1 beta, in mediating increased bone resorption during estrogen deficiency in women. Although either cytokine blocker reduced serum CTX by about one half, the effect of combined blockade could not be tested because of concerns about toxicity. The data do not exclude direct or indirect contributory roles for RANKL or for other cytokines. 相似文献
5.
Shreyasee Amin B Lawrence Riggs Elizabeth J Atkinson Ann L Oberg L Joseph Melton Sundeep Khosla 《Journal of bone and mineral research》2004,19(7):1075-1083
The role of the IGFs and IGFBPs on age-related changes in BMD in adult men and women is not well understood. Studying an age-stratified community based sample of 344 men and 276 women, we found higher IGFBP-2 levels to be associated with lower BMD. IGFBP-2, which increases with age in both men and women, was the strongest, most consistent predictor of BMD among the IGF/IGFBPs studied. INTRODUCTION: Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are important regulators of tissue growth and metabolism, but their association with BMD in adult men and women is controversial. MATERIALS AND METHODS: In an age-stratified, random sample of the community population, we examined the role of serum levels of IGF-I, IGF-II, and IGFBP-1, -2, and -3 on BMD of the proximal femur (total hip), lateral spine, midshaft, and ultradistal radius as measured by DXA. We explored the association before and after adjustment for potential confounders, including age, bioavailable estradiol and testosterone, sex hormone binding globulin (SHBG), and measures of total fat and skeletal muscle mass. RESULTS: We studied 344 men (age, 23-90 years) and 276 women (age, 21-93 years; 166 postmenopausal) not on hormone replacement or oral contraceptives. In both men and women, IGF-I and IGFBP-3 levels fell with advancing age, whereas IGFBP-2 levels tended to rise with age. There was an inverse association of IGFBP-2 with BMD at most skeletal sites in men and both premenopausal and postmenopausal women, whereas lower IGF-I and IGFBP-3 were associated with lower BMD in men and postmenopausal women only. Lower IGF-II was associated with lower BMD in men only. There were no associations between IGFBP-1 and BMD in either sex. After adjustment for age, in most cases, we found no further associations between IGF-I, IGF-II, or IGFBP-3 and BMD. In contrast, after age adjustment, higher IGFBP-2 remained a predictor of lower BMD in men and postmenopausal women at all sites except for the lateral spine (for men: r = -0.21, -0.20, and -0.19, all p < 0.001; and for postmenopausal women: r = -0.34, -0.24, and -0.25, all p < 0.01, for the total hip, midshaft, and ultradistal radius, respectively). IGFBP-2 remained an independent negative predictor of BMD in men, postmenopausal women, and all women combined after additional adjustment for bioavailable sex steroids, but not at all sites after adjustment for SHBG and muscle mass. In premenopausal women, IGFBP-2 had similar associations as seen in postmenopausal women, but they were weaker and not statistically robust. CONCLUSIONS: Among the IGF/IGFBPs in our study, IGFBP-2 was a key negative predictor of BMD among men and women, particularly postmenopausal women. Our findings suggest a potential role of the IGF/IGFBP system in regulating bone loss in aging men and women and identify a previously under-recognized, potentially deleterious role for IGFBP-2, a known inhibitor of IGF action that increases with age in both sexes. Whether the action of the IGF/IGFBP system on bone metabolism is mediated partly through its effects on muscle mass or SHBG deserves further study. 相似文献
6.
7.
R Zachariah AD Harries MP Spielmann V Arendt D Nchingula R Mwenda O Courtielle P Kirpach B Mwale FML Salaniponi 《Malawi medical journal : the journal of Medical Association of Malawi》2002,14(2):10-12
In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out to determine i) whether faecal Escherichia coli (E.coli) resistance to co-trimoxazole in TB patients changed with time and ii) whether the resistance pattern was different in HIV positive TB patients who were taking co-trimoxazole prophylaxis. Co-trimoxazole resistance among E.coli isolates in TB patients at the time of registration was 60% in 1999 and 77% in 2001 (p<0.01). Resistance was 89% among HIV-infected TB patients (receiving co-trimoxazole), while in HIV negative patients (receiving anti-TB therapy alone) it was 62% (p<0.001). The study shows a significant increase of E.coli resistance to co-trimoxazole in TB patients which is particularly prominent in HIV infected patients on co-trimoxazole prophylaxis. Since a high degree of plasmid-mediated transfer of resistance exists between E.coli and the Salmonella species, these findings could herald limitations on the short and long term benefits to be anticipated from the use of co-trimoxazole prophylaxis in preventing non-typhoidal salmonella bacteraemia and enteritis in HIV infected TB patients in Malawi. 相似文献
8.
The exponential growth in the number of computed tomography scanners in the United States between 1975 and 1977 was associated with a transient increase (11.9 and 14.4% for men and women, respectively) in annual crude mortality rates for primary malignant brain tumor from 1976 through 1978. This transient increase in mortality appears to have been an artifactual epiphenomenon associated with the introduction of a new technology. 相似文献
9.
CHERYL K. ROTH AD RNC BONNIE RILEY RN CCRN SUSAN M. COHEN DSN RN 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1992,21(4):310-311
Advances in technology and complex care have enabled women with various health problems to become and remain pregnant. Consequently, health-care practitioners are seeing an increasing number of pregnant women who have aortic aneurysms. This case study describes the culturally sensitive intrapartum care of a Middle Eastern woman with ascending and descending aortic aneurysms. 相似文献
10.
J E Riggs 《Mechanisms of ageing and development》1991,61(2):197-208
Pancreatic cancer (PanC) is an extraordinarily lethal neoplasm that is currently the fifth leading cause of cancer death in the United States. Annual age-specific mortality rates for PanC in the U.S. from 1962 to 1987 were subjected to longitudinal Gompertzian analysis. Age-specific PanC mortality rate distributions between age 30 and 60 years were determined by a common fixed intersect point and a variable competitive factor. The intersect point for PanC occurred at age 59.5 years and mortality rate 37.4 per 100,000 for men, and at age 53.2 years and mortality rate 7.9 per 100,000 for women. These intersect points are determined by genetic and environmental influences upon mortality. The observation that these points have remained fixed suggests that there has been no significant alteration in environmental etiopathogenic influences upon PanC mortality. Longitudinal Gompertzian analysis suggests that the emergence of PanC in the U.S. as a significant cause of cancer mortality has been the consequence of competitive influences upon PanC mortality dynamics. 相似文献