全文获取类型
收费全文 | 405篇 |
免费 | 22篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 13篇 |
妇产科学 | 8篇 |
基础医学 | 41篇 |
口腔科学 | 24篇 |
临床医学 | 56篇 |
内科学 | 113篇 |
皮肤病学 | 3篇 |
神经病学 | 6篇 |
特种医学 | 74篇 |
外科学 | 21篇 |
综合类 | 18篇 |
预防医学 | 25篇 |
眼科学 | 1篇 |
药学 | 20篇 |
中国医学 | 3篇 |
肿瘤学 | 12篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 14篇 |
2015年 | 5篇 |
2014年 | 9篇 |
2013年 | 15篇 |
2012年 | 4篇 |
2011年 | 6篇 |
2010年 | 18篇 |
2009年 | 24篇 |
2008年 | 5篇 |
2007年 | 19篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 30篇 |
1997年 | 32篇 |
1996年 | 30篇 |
1995年 | 25篇 |
1994年 | 19篇 |
1993年 | 19篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 11篇 |
1989年 | 16篇 |
1988年 | 14篇 |
1987年 | 18篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 3篇 |
排序方式: 共有439条查询结果,搜索用时 31 毫秒
21.
Ageing appearance in China: biophysical profile of facial skin and its relationship to perceived age
AE Mayes PG Murray DA Gunn CC Tomlin SD Catt YB Wen LP Zhou HQ Wang M Catt SP Granger 《Journal of the European Academy of Dermatology and Venereology》2010,24(3):341-348
Background Perceived age is important to women and is a primary driver for topical product use and facial cosmetic surgery. Changes in facial features and biophysical skin parameters with chronological age and their associations with perceived age have not been described in Asian populations. Objective To investigate the relationship between biophysical properties of the skin, visual features of skin ageing and perceived facial age in Chinese women. Methods Facial photographs were collected of 250 Chinese women, aged 25–70 years in Shanghai, China. The perceived facial age was determined and related to the chronological age for each participant and to a range of visual assessments of skin appearance and objective biophysical measurements of the skin. The profile of changes in these parameters with age was investigated together with the differences in those parameters for women judged to look younger than their chronological age and those judged to look older than their chronological age. Results Large discrepancies in perceived age (up to 29 years) were found in women of the same chronological age. Each objective skin measure and visual assessment parameter had a stronger correlation with perceived age than with chronological age. The strongest relationships to perceived age were for wrinkles and hyperpigmentation. Skin colour, hydration and trans‐epidermal water loss (TEWL) had weaker associations with perceived age. Women judged to look older than their chronological age had significantly higher scores than those judged to look younger for coarse wrinkles and hyperpigmentation across all age groups. The appearance differences between these groups were evident in composite facial images of the same average chronological age. Conclusions We have identified the skin attributes which differ with perceived age in Chinese women. Perceived age is a better measure of the biological age of facial skin than is chronological age in this population. 相似文献
22.
Nandakumar Narayanaswamy Surulivel Rajan Mallayasamy Anand R Manoharan SD Rajendiran 《The International journal of pharmacy practice》2007,15(1):69-73
Objective India is a country with the availability of a large number of pharmaceutical preparations as branded generics. At the time of this study there was no established pharmacovigilance system at the national level except a co‐ordinating centre at the national capital. The study site was a tertiary care teaching hospital with a bed capacity of 500 and with an average of 200 outpatient visits and 50 inpatient admissions per day. The hospital did not have any system of monitoring and documenting adverse drug reactions. The objective of the study was to introduce an adverse drug reaction (ADR) monitoring programme at a tertiary care teaching hospital and assess ADR‐related issues in both inpatient and outpatient departments. Method All departments willing to report ADRs were included in the study, which was carried out for one year. Physicians and nurses filled in the notification forms when they encountered suspected ADR cases. These cases were then assessed by a panel of four judges. According to Naranjo's algorithm, the ADRs were assessed and classified based on World Health Organization (WHO) classification. Key findings A total of 288 suspected cases were reported and 264 ADRs were confirmed by the panel. According to Naranjo's probability scale, 83 cases were categorized as ‘probable’, 181 cases were classified as ‘possible’, and none were classified as ‘unlikely’ or ‘definite’. The most common classes of drugs involved were antibiotics (25%), psychotropics (20%), analgesic and cardiovascular agents (14% each). Generalised itch and rash, tremors, urticarial drug reaction, oral ulcer, gastritis and akathesia and extrapyramidal symptoms were found to be the most common ADRs observed; 2.1% of the patients in the studied departments had ADRs. Conclusion The ADR reporting system was initiated at the hospital and was well received by the physicians. Appreciable participation of physicians was noted during the study in reporting ADRs. The study also gave an insight into the awareness of physicians about ADR‐related issues. The number of ADRs reported was reasonably comparable with the findings of other authors from India. 相似文献
23.
Perkins SN; Hursting SD; Haines DC; James SJ; Miller BJ; Phang JM 《Carcinogenesis》1997,18(5):989-994
Transgenic mice with both alleles of the p53 tumor suppressor gene product
'knocked out' by gene targeting are susceptible to early development of
tumors, chiefly lymphomas and sarcomas. Compared with the control group,
administration of dehydroepiandrosterone (DHEA) at 0.3% of the diet to male
p53-deficient mice extended their lifespan by delaying death due to
neoplasms (from 105 to 166 days on study, P = 0.002), primarily by
suppressing lymphoblastic lymphoma (from 45 to 6% of neoplastic deaths, P =
0.010). Treatment with a synthetic DHEA analog,
16alpha-fluoro-5-androsten-17-one (compound 8354), at 0.15% of the diet
also increased lifespan, to 140 days for mice that developed tumors (P =
0.037). The effects of these steroids on lifespan and tumor development did
not appear to be strongly related to inhibition of food consumption and
weight gain, in that a group pair-fed with control diet to the reduced food
consumption of the DHEA-treated group developed and died of the same types
of neoplasms at the same rate as the controls fed ad libitum. The
chemopreventive effect of these steroids has been proposed to be due to
suppression of DNA synthesis by inhibition of glucose 6-phosphate
dehydrogenase, the rate-limiting enzyme of the pentose phosphate pathway.
Although DHEA and its analog are strong non- competitive inhibitors of this
enzyme in vitro, treatment with DHEA did not deplete cellular nucleotide
pools in the liver, as would have been predicted. The chemopreventive
effect of DHEA in this model may be due to steroid-induced thymic atrophy
and suppression of T cell lymphoma, permitting these mice to survive long
enough to develop tumors with longer latency.
相似文献
24.
25.
26.
27.
28.
29.
Dunnick NR; Svetkey LP; Cohan RH; Newman GE; Braun SD; Himmelstein SI; Bollinger RR; McCann RL; Wilkinson RH Jr; Klotman PE 《Radiology》1989,171(1):219-222
Intravenous digital subtraction renal angiography (DSRA) has been compared with conventional angiography only in small, selected series of hypertensive patients. The authors prospectively examined with intravenous DSRA 94 patients at increased risk for renovascular hypertension and compared these studies with conventional angiography. A stenosis of at least one main renal artery was identified with intravenous DSRA in 22 patients and confirmed in 20 patients. No significant stenoses were seen with conventional angiography in any of the 64 patients in whom lesions were not seen with intravenous DSRA. Since inadequate DSRA studies were considered positive for renal artery stenosis, the sensitivity of intravenous DSRA was 100% (25 of 25); specificity, 93% (64 of 69); positive predictive value, 83% (25 of 30); and negative predictive value, 100% (64 of 64). The authors conclude that intravenous DSRA is a sensitive test for identifying stenosis of the main renal arteries and is appropriate to use as a screening test among patients at increased risk for renovascular hypertension. 相似文献
30.
Jaundice develops in many patients with liver metastases from colorectal adenocarcinoma during hepatic arterial infusion chemotherapy (HAIC). The usual cause is thought to be hepatotoxicity from the chemotherapeutic agent or biliary obstruction from progressive neoplastic disease. The authors evaluated the abdominal computed tomography and ultrasound examinations performed on 49 patients who were jaundiced during long-term HAIC. In only one patient was diffuse intrahepatic biliary dilatation caused by an obstructing mass in the porta. Two patients had metastatic hepatic lesions causing focal biliary obstruction. Intrahepatic dilatation without an obstructing mass occurred in 20 patients. Percutaneous or endoscopic cholangiograms were commonly interpreted prospectively as showing extrinsic compression by metastases, but no mass was confirmed on imaging studies. Seven patients had focal intrahepatic ductal dilatation from stricture without an associated mass. The remaining 19 patients had normal-caliber ducts; their jaundice was caused by chemical hepatitis. This series suggests that the most common causes of jaundice in these patients are chemical hepatitis and common bile duct stricture, complications of intraarterial chemotherapy, rather than neoplastic obstruction. Stricture formation may be confused with extrinsic compression on direct cholangiograms. 相似文献