全文获取类型
收费全文 | 12919篇 |
免费 | 1097篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 227篇 |
儿科学 | 442篇 |
妇产科学 | 173篇 |
基础医学 | 1508篇 |
口腔科学 | 260篇 |
临床医学 | 1338篇 |
内科学 | 2647篇 |
皮肤病学 | 176篇 |
神经病学 | 1473篇 |
特种医学 | 808篇 |
外科学 | 1495篇 |
综合类 | 289篇 |
一般理论 | 3篇 |
预防医学 | 1137篇 |
眼科学 | 250篇 |
药学 | 934篇 |
中国医学 | 8篇 |
肿瘤学 | 905篇 |
出版年
2021年 | 125篇 |
2020年 | 110篇 |
2019年 | 158篇 |
2018年 | 198篇 |
2017年 | 138篇 |
2016年 | 170篇 |
2015年 | 202篇 |
2014年 | 273篇 |
2013年 | 487篇 |
2012年 | 590篇 |
2011年 | 620篇 |
2010年 | 404篇 |
2009年 | 337篇 |
2008年 | 548篇 |
2007年 | 644篇 |
2006年 | 564篇 |
2005年 | 610篇 |
2004年 | 603篇 |
2003年 | 570篇 |
2002年 | 512篇 |
2001年 | 236篇 |
2000年 | 260篇 |
1999年 | 239篇 |
1998年 | 286篇 |
1997年 | 241篇 |
1996年 | 252篇 |
1995年 | 202篇 |
1994年 | 173篇 |
1993年 | 189篇 |
1992年 | 220篇 |
1991年 | 209篇 |
1990年 | 181篇 |
1989年 | 207篇 |
1988年 | 195篇 |
1987年 | 210篇 |
1986年 | 190篇 |
1985年 | 210篇 |
1984年 | 203篇 |
1983年 | 188篇 |
1982年 | 187篇 |
1981年 | 167篇 |
1980年 | 151篇 |
1979年 | 132篇 |
1978年 | 155篇 |
1977年 | 118篇 |
1976年 | 134篇 |
1975年 | 136篇 |
1974年 | 95篇 |
1973年 | 77篇 |
1968年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Donald E. Addington Emily McKenzie Jean Addington Scott Patten Harvey Smith Carol Adair 《Early intervention in psychiatry》2007,1(2):157-167
Aim: The purpose of this project was to operationalize and apply a previously identified set of performance measures designed to evaluate services for those experiencing a first episode of a schizophrenia spectrum disorder. Methods: Operational definitions were developed for previously identified measures through an iterative process of discussions between clinical experts and health‐care evaluators. Data were collected from existing sources including corporate databases, clinical databases and chart review. Results: Definitions were developed for 44 measures covering seven of eight domains recommended for service level evaluation by the Canadian Institute for Health Information domains. Forty measures could be calculated. Conclusions: The measures represent a comprehensive set of performance measures suitable for the evaluation of services for people with a first‐episode psychosis. The measures could be used by other services in order to establish standards and norms for routine clinical practice. 相似文献
42.
Conference Reports: This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de. 相似文献
43.
The mutational specificity of the syn dihydrodiol epoxide of 5-methylchrysene in the supF gene of the pSP189 vector was examined. Transversion mutations at GC pairs predominated with G → T and G → C changes accounting for 42 and 21% of total base change mutations. The types of mutations found reflect the previously determined chemical preference of this reactive species for reaction with deoxyguanosine residues in DNA. 相似文献
44.
Ya Qin Li Venu Gopal Pratibha Kadam Shawn Files Harvey Preisler 《Medical oncology (Northwood, London, England)》1992,9(1):3-9
A comparison of three different approaches to detect MDR1 expression in myeloid leukemia cells was undertaken. With respect to the 4 different antibodies studied, a high proportion of false positive reactions were detected. Substantial discordance between MDR1 expression as indicated by Northern blot analysis, PCR, and immunohistochemistry was found. These findings complicate the clinical interpretation of data derived from these methods. 相似文献
45.
46.
OBJECTIVE: The aim of this study was to assess the severity of epilepsy and
its effect on patients lives, and to describe patients' use of and
attitudes to health care. METHOD: A questionnaire was sent to 595 people
with epilepsy identified from 14 general practices in north-west Bristol.
All patients aged 16 years and over receiving anti-epileptic medication for
their epilepsy were included in the study. Areas investigated included
severity of epilepsy and its effect on quality of life, anti-epileptic
medication and its perceived effect, health care utilization and
preferences for health care. RESULTS: Seizure frequency was strongly
associated with adverse effects of epilepsy. Attacks of epilepsy were
experienced at least monthly by 20.4% (95% confidence intervals (Cl)
17.0-23.7%) of patients, 29.4% (25.4-33.4%) took more than one
anti-epileptic drug, 56.1% (50.1-62.2%) reported drug side effects, 74.1%
(70.3-77.8%) would prefer to receive all or most of their epilepsy care in
a general practice setting, and 69.8% (63.5- 76.2%) would like contact with
a primary care-based epilepsy specialist nurse. During the previous year
42.4% (35.9-48.8%) of patients had not seen a doctor about their epilepsy.
Of patients who had attended the general practice only 13.4% (9.6-17.2%)
had regular arrangements to see their GP about epilepsy. Patients receiving
both primary and secondary care had the greatest needs and wants for
improved care. CONCLUSIONS: Structured care, including regular
appointments, co-ordination of primary and secondary care, and increased
monitoring and discussion, may improve the quality of life of people with
epilepsy, but requires evaluation.
相似文献
47.
48.
49.
SCHWANN CELLS AND THE REGROWTH OF AXONS IN THE MAMMALIAN CNS: A REVIEW OF TRANSPLANTATION STUDIES IN THE RAT VISUAL SYSTEM 总被引:2,自引:0,他引:2
A. R. Harvey G. W. Plant M. M. L. Tan 《Clinical and experimental pharmacology & physiology》1995,22(8):569-579
1. We have used peripheral nerve transplants or cultured Schwann cells grafted in association with different types of polymer to study axonal regrowth in the rat visual system. In some instances the glia were co-grafted with fetal tectal tissue. 2. The studies have two main aims: (i) to determine whether retinal axons can be induced to regrow at a site distant from their cell soma, that is, after damage to the brachial region of the optic tract; (ii) to determine whether retinal axons exposed to Schwann cells retain the ability to recognize their appropriate target neurons in CNS tissue. 3. In brachial lesion studies, Schwann cells were placed in the lesion site in association with nitrocellulose papers, within polycarbonate tubes in the presence or absence of a supporting extracellular matrix (ECM), or within polymer hydrogel scaffolds. Autologous sciatic nerve grafts were also used. Immuno-histochemical studies revealed the presence of regenerating axons within all polymer bridges. Regrowth of retinal axons was also seen, however, growth was not extensive and was limited to the proximal 1–1.5 mm of the implants. 4. In target innervation experiments, two surgical paradigms were developed. In one experiment, a segment of sciatic nerve was autografted onto the transected optic nerve in adult rats and the distal end of each graft was placed adjacent to fetal tectal (target) tissue implanted into the frontal cortex. To date, we have not been able to demonstrate selective recognition of target regions within tectal transplants by retinal axons exiting the sciatic nerve implants. 5. In the second experiment, Schwann cells were mixed with fetal tectal cells and co-grafted to the midbrain of newborn host rats. Schwann cells altered the characteristic pattern of host retinal growth into tectal grafts; in some cases axons were induced to grow away from appropriate target areas by nearby co-grafted Schwann cells. 6. In summary, Schwann cell/polymer scaffolds may provide a useful way of promoting the regrowth of damaged axons in the CNS, however: (i) in adults, at least, their effectiveness is reduced if they are located at a distance from the cell bodies giving rise to regenerating axons; (ii) in some circumstances exposure to a peripheral glial environment may affect the capacity of regenerating axons to recognize appropriate target cells in the CNS neuropil. 相似文献
50.
BACKGROUND: A simple, rapid, inexpensive method for measuring the flow in a
patient's vascular access would permit routine monitoring during
haemodialysis, and hence provide information of access graft deterioration
sufficiently early to increase the success of minimally invasive remedial
procedures. This paper reports the validation of such a method in animals.
METHODS: A PTFE graft was implanted in sheep between the carotid artery and
the jugular vein. While the sheep was under general anaesthesia and on an
haemodialysis circuit, ultrasound velocity in its blood was perturbed by
the injection of a 5-10 ml bolus of isotonic NaCl. The pump tubing flow was
measured by a transit-time blood flow meter. This flow was combined with
the areas of perturbation generated by the injection before and after
mixing in the access flow to estimate graft flow. The calculated graft flow
was compared to flow measured directly by a transit-time probe on the same
carotid artery. RESULTS: Over a 10-fold range, 120-1260 ml/min, graft flow
measured by ultrasound velocity dilution agreed well with graft flow
measured directly with a scatter of 76 ml/min about the regression line.
CONCLUSION: Ultrasound velocity dilution provides a method for measuring
flow in the graft accurate enough for clinical evaluation of patients on
dialysis.
相似文献