全文获取类型
收费全文 | 3852篇 |
免费 | 286篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 171篇 |
妇产科学 | 56篇 |
基础医学 | 389篇 |
口腔科学 | 84篇 |
临床医学 | 333篇 |
内科学 | 1050篇 |
皮肤病学 | 177篇 |
神经病学 | 294篇 |
特种医学 | 206篇 |
外科学 | 409篇 |
综合类 | 67篇 |
一般理论 | 5篇 |
预防医学 | 300篇 |
眼科学 | 71篇 |
药学 | 279篇 |
中国医学 | 3篇 |
肿瘤学 | 240篇 |
出版年
2021年 | 34篇 |
2020年 | 27篇 |
2019年 | 45篇 |
2018年 | 46篇 |
2017年 | 32篇 |
2016年 | 49篇 |
2015年 | 57篇 |
2014年 | 77篇 |
2013年 | 102篇 |
2012年 | 163篇 |
2011年 | 138篇 |
2010年 | 115篇 |
2009年 | 116篇 |
2008年 | 157篇 |
2007年 | 161篇 |
2006年 | 132篇 |
2005年 | 165篇 |
2004年 | 165篇 |
2003年 | 159篇 |
2002年 | 132篇 |
2001年 | 146篇 |
2000年 | 141篇 |
1999年 | 123篇 |
1998年 | 79篇 |
1997年 | 77篇 |
1996年 | 68篇 |
1995年 | 69篇 |
1994年 | 48篇 |
1993年 | 43篇 |
1992年 | 91篇 |
1991年 | 79篇 |
1990年 | 75篇 |
1989年 | 91篇 |
1988年 | 75篇 |
1987年 | 74篇 |
1986年 | 71篇 |
1985年 | 61篇 |
1984年 | 36篇 |
1983年 | 37篇 |
1982年 | 34篇 |
1981年 | 32篇 |
1980年 | 26篇 |
1979年 | 52篇 |
1978年 | 42篇 |
1977年 | 32篇 |
1976年 | 31篇 |
1974年 | 28篇 |
1972年 | 29篇 |
1971年 | 25篇 |
1967年 | 25篇 |
排序方式: 共有4160条查询结果,搜索用时 15 毫秒
1.
A Ascari-Raccagni†‡ MG Righini† 《Journal of the European Academy of Dermatology and Venereology》2006,20(5):514-516
BACKGROUND: Repairing dorsal nasal defects is a frequent challenge for dermatologic surgeons, mainly due to the high frequency of basal cell carcinomas on this site. Obvious scars, mismatched skin and distortion of the nasal contour are the surgical hazards that must be avoided in these cases. AIM: Our aim was to perform surgery involving a simple flap in order to repair medium to large defects on the dorsal side of the nose. METHODS: The dorsal horizontal advancement flap was studied in 12 patients, in order to evaluate the benefits and limits of this surgical procedure. RESULTS: The resulting scars on most of our patients were well-camouflaged among their natural skin lines, and there was neither distortion of the alar contour nor the nostril. CONCLUSIONS: This flap is easy to perform and, in selected cases, provides an outstanding alternative to second-intention healing, full-thickness skin grafts, transposition, rotation and pedicle flaps. 相似文献
2.
3.
New 2,5-dialkylpyrrolidines found in the venom of Monomorium indicum include trans-2-butyl-5-(4-pentenyl)pyrrolidine [1], trans-2-butyl-5-(6-heptenyl)pyrrolidine [4], trans-5-(5-hexenyl)-2-(4-pentenyl)pyrrolidine [6], trans-5-(6-heptenyl)-2-(5-hexenyl)pyrrolidine [8], and trans-5-heptyl-2-hexylpyrrolidine [16], whose structures were confirmed by synthesis. The concomitance of five previously reported trans-2,5-dialkyl-pyrrolidines along with small amounts of the cis isomers and N-methyl analogues makes the venom of M. indicum the most qualitatively diverse blend of alkaloids reported from an ant to date. The toxicities to termites of four of these alkaloids were determined. 相似文献
4.
Patients with uremia have excess levels of parathyroid hormone (PTH). It has been reported that excess PTH is associated with bone marrow fibrosis. The present study was undertaken to examine the in vitro effect of intact 1-34 PTH and the active 1-34 N-terminal fragment on human bone-marrow-derived fibroblasts. Proliferation of fibroblasts was not stimulated by PTH in concentrations present in uremia (5-30 U/ml) nor by uremic sera which contained either high or low PTH levels. The lack of stimulation contrasted with the activity of both PTH preparations in other systems, i.e., inhibitory to erythroid colonies and stimulatory to heart muscle cells. 相似文献
5.
Alex Y. Chang Z. Nora Tu Julia L. Smith Philip Bonomi Thomas J. Smith Peter H. Wiernik Ronald Blum 《Investigational new drugs》1995,13(2):137-141
Summary Fifty-five patients with metastatic non-small cell lung cancer (NSCLC) were entered into this phase II randomized study for evaluating three new agents: gallium nitrate, amonafide and teniposide. The patients had to have ECOG performance status 0 or 1, no prior chemotherapy, and adequate hematological, hepatic and renal functions. Forty-seven patients were eligible and evaluable. Fourteen were randomized to receive gallium nitrate, 18 to amonafide and 15 to teniposide. Seventy-four percent of eligible patients were male. The majority of patients (89%) had an ECOG performance status 1. ECOG grade 4 toxicity occurred twice in patients on gallium nitrate, seven times on amonafide and 18 times on teniposide. The cause of death was attributed to amonafide in one patient (from sepsis) and to teniposide in two patients (due to infection and leukopenia). There was no objective response in all the patients entered. The overall survival times ranged from 2 weeks to 156 weeks with a median of 23 weeks. There were no survival differences among the three treatment arms. We conclude that gallium nitrate, amonafide and teniposide are inactive in metastatic NSCLC and do not warrant any further testing in this disease.The contents of this study is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute. 相似文献
6.
American Indian--Alaska Native youth health. 总被引:6,自引:0,他引:6
OBJECTIVE--To assess risk behaviors, health problems, worries and concerns, and resiliency-promoting factors among American Indian-Alaska Native adolescents. DESIGN--Survey. SETTING--Nonurban schools from eight Indian Health Service areas. PARTICIPANTS--A total of 13,454 seventh- through 12th-grade American Indian-Alaska Native youths. MAIN OUTCOME MEASURES--revised version of the Adolescent Health Survey, a comprehensive, anonymous, self-report questionnaire with 162 items addressing 10 dimensions of health. RESULTS--Poor physical health was reported by 2% of the study sample and was significantly correlated with social risk factors of physical and/or sexual abuse, suicide attempts, substance abuse, poor school performance, and nutritional inadequacies. Injury risk behaviors included never wearing seatbelts (44%), drinking and driving (37.9% of driving 10th through 12th graders), and riding with a driver who had been drinking (21.8%). Physical and sexual abuse prevalence was 10% and 13%, respectively, with 23.9% of females reporting physical abuse and 21.6% of females reporting sexual abuse by the 12th grade. Almost 6% of the entire sample endorsed signs of severe emotional distress. Eleven percent of the teens surveyed knew someone who had killed himself or herself, and 17% had attempted suicide themselves. Sixty-five percent of males and 56.8% of females reported having had intercourse by the 12th grade. Weekly or more frequent alcohol use rose from 8.2% of seventh graders to 14.1% by the 12th grade; for males, the survey noted an increase in regular alcohol use of 3% to 5% a year to 27.3% by the 12th grade. For each variable measured, rates are much higher for American Indian adolescents than those for rural white Minnesota youth, except for age at first intercourse and alcohol use. CONCLUSIONS--American Indian-Alaska Native adolescents reported high rates of health-compromising behaviors and risk factors related to unintentional injury, substance use, poor self-assessed health status, emotional distress, and suicide. Interventions must be culturally sensitive, acknowledge the heterogeneity of Indian populations, be grounded in cultural traditions that promote health, and be developed with full participation of the involved communities. 相似文献
7.
TP Amadeu† AB Seabra‡ MG de Oliveira‡ AMA Costa† 《Journal of the European Academy of Dermatology and Venereology》2007,21(5):629-637
BACKGROUND: Nitric oxide (NO) plays a key role in wound repair and S-nitrosothiols like S-nitrosoglutathione (GSNO) are well known NO donors. METHODS: Animals were separated in two groups and submitted to excisional wounds on the dorsal surface at the first day. GSNO (100 microm)-containing hydrogels were topically applied on the wound bed in the GSNO group, daily, during the first 4 days. Control group was topically treated with hydrogel without GSNO for the same period. Wound contraction and re-epithelialization were measured. Animals were sacrificed 21 days after wounding. Samples of lesion and normal tissue were formalin-fixed, paraffin embedded for histological analysis. RESULTS: Wound contraction, measured 14 and 21 days after wounding, was greater in the GSNO group than in the control group (P<0.05 for both). The re-epithelialized wound area, measured 14 days after wounding, was higher in the GSNO group than in the control group (P<0.05). A higher amount of inflammatory cells was observed in superficial and deep areas of the granulation tissue of the control group compared to the GSNO group. Twenty-one days after wounding, thin red-yellow collagen fibers arranged perpendicularly to the surface were found in the granulation tissue of the control group, whereas in the GSNO-treated group collagen fibers were thicker and arranged parallel to the surface. Increased number of mast cells was observed in the GSNO group compared with that in the control group. Vascularization and myofibroblast distribution were similar in both groups. CONCLUSION: Topical application of GSNO-containing hydrogel during the early phases of rat cutaneous wound repair accelerates wound closure and re-epithelialization and affects granulation tissue organization. 相似文献
8.
9.
The present study was conducted to examine changes in water concentration in the ventral prostate of adult rats at different intervals following castration. The prostatic dry weight was obtained by drying the fresh prostate at 70 degrees C for at least 110 hr and the prostatic water content was calculated from its wet and dry weight. Under normal conditions, the prostatic water concentration ranges from 81.9 to 82.7% in uncastrated rats. The prostatic water concentration started to increase at 8 hr postcastration (83.1%) but this increase was not statistically significant. By 16 hr postcastration, the prostatic water concentration (83.8%) became significantly higher than that of the uncastrated animals. In rats of day 1 to day 10 postcastration, the prostate contained significantly more water (84.4%-84.7%) than those in uncastrated animals. By day 21 postcastration, the prostatic water concentration (81.5%) was not significantly different from that of uncastrated rats. Unlike the prostate, the skeletal muscle did not significantly change the water concentration following castration. The 51Cr-EDTA space in the prostate was not significantly different in rats before and after castration. These results indicate that water imbibition in the rat prostate is associated with an active period of prostatic regression and that the change in the 51Cr-EDTA space during prostatic regression is not the major cause of water imbibition in the tissue. Therefore, the present findings suggest that castration-induced water imbibition in the rat prostate is caused by an increase in the intracellular water space. 相似文献
10.
Pelvic fractures are frequently complicated by concomitant vascular lacerations involving, particularly, branches originating from the internal iliac arteries. Massive hemorrhage may be difficult to be treated surgically. In such cases interventional radiology can be helpful and able to treat definitely extensive hemorrhage caused by pelvic trauma. 相似文献