全文获取类型
收费全文 | 9580篇 |
免费 | 583篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 207篇 |
妇产科学 | 97篇 |
基础医学 | 1602篇 |
口腔科学 | 348篇 |
临床医学 | 699篇 |
内科学 | 1854篇 |
皮肤病学 | 273篇 |
神经病学 | 1167篇 |
特种医学 | 580篇 |
外科学 | 1389篇 |
综合类 | 65篇 |
一般理论 | 4篇 |
预防医学 | 379篇 |
眼科学 | 113篇 |
药学 | 760篇 |
中国医学 | 11篇 |
肿瘤学 | 615篇 |
出版年
2022年 | 49篇 |
2021年 | 122篇 |
2020年 | 104篇 |
2019年 | 135篇 |
2018年 | 171篇 |
2017年 | 143篇 |
2016年 | 166篇 |
2015年 | 199篇 |
2014年 | 326篇 |
2013年 | 372篇 |
2012年 | 530篇 |
2011年 | 543篇 |
2010年 | 377篇 |
2009年 | 361篇 |
2008年 | 535篇 |
2007年 | 580篇 |
2006年 | 610篇 |
2005年 | 638篇 |
2004年 | 578篇 |
2003年 | 597篇 |
2002年 | 645篇 |
2001年 | 132篇 |
2000年 | 115篇 |
1999年 | 162篇 |
1998年 | 159篇 |
1997年 | 133篇 |
1996年 | 109篇 |
1995年 | 96篇 |
1994年 | 82篇 |
1993年 | 70篇 |
1992年 | 68篇 |
1991年 | 84篇 |
1990年 | 54篇 |
1989年 | 52篇 |
1988年 | 54篇 |
1987年 | 70篇 |
1986年 | 35篇 |
1985年 | 56篇 |
1984年 | 40篇 |
1983年 | 42篇 |
1982年 | 47篇 |
1981年 | 45篇 |
1980年 | 44篇 |
1978年 | 49篇 |
1977年 | 35篇 |
1976年 | 48篇 |
1975年 | 32篇 |
1974年 | 50篇 |
1973年 | 42篇 |
1970年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
1.
2.
3.
Uwe Schneider PhD Antony Lomax Peter Pemler Jürgen Besserer Dieter Ross Norbert Lombriser Barbara Kaser-Hotz 《Strahlentherapie und Onkologie》2006,182(11):647-652
BACKGROUND AND PURPOSE: There is concern about the increase of radiation-induced malignancies with the application of modern radiation treatment techniques such as intensity-modulated radiotherapy (IMRT) and proton radiotherapy. Therefore, X-ray scatter and neutron radiation as well as the impact of the primary dose distribution on secondary cancer incidence are analyzed. MATERIAL AND METHODS: The organ equivalent dose (OED) concept with a linear-exponential and a plateau dose-response curve was applied to dose distributions of 30 patients who received radiation therapy of prostate cancer. Three-dimensional conformal radiotherapy was used in eleven patients, another eleven patients received IMRT with 6-MV photons, and eight patients were treated with spot-scanned protons. The treatment plans were recalculated with 15-MV and 18-MV photons. Secondary cancer risk was estimated based on the OED for the different treatment techniques. RESULTS: A modest increase of 15% radiation-induced cancer results from IMRT using low energies (6 MV), compared to conventional four-field planning with 15-MV photons (plateau dose-response: 1%). The probability to develop a secondary cancer increases with IMRT of higher energies by 20% and 60% for 15 MV and 18 MV, respectively (plateau dose-response: 2% and 30%). The use of spot-scanned protons can reduce secondary cancer incidence as much as 50% (independent of dose-response). CONCLUSION: By including the primary dose distribution into the analysis of radiation-induced cancer incidence, the resulting increase in risk for secondary cancer using modern treatment techniques such as IMRT is not as dramatic as expected from earlier studies. By using 6-MV photons, only a moderate risk increase is expected. Spot-scanned protons are the treatment of choice in regard to secondary cancer incidence. 相似文献
4.
There is some evidence suggesting that Parkinson's disease (PD) patients exhibit lower body weight when compared to age-matched healthy subjects. Low body mass index (BMI) is correlated with low bone mineral density, both of which are major risk factors for hip fractures. Possible determinants of weight loss in PD patients include hyposmia, impaired hand-mouth coordination, difficulty chewing, dysphagia, intestinal hypomotility, depression, decreased reward processing of dopaminergic mesolimbic regions, nausea, and anorexia as the side effects of medication, and increased energy requirements due to muscular rigidity and involuntary movements. It is unclear whether PD patients in general, or only a subgroup of those affected, definitely show lower BMI in the advanced stages of the disease. We therefore recommend that the body weight of PD patients be monitored monthly as the disease progresses, and that a patient's nutrition should be supplemented with sufficient amounts of vitamin D and calcium to reduce the risk of hip fractures and strengthen bone density. Because meal times may coincide with unpredictable off periods associated with akinesia and impaired hand-mouth coordination, PD patients also need flexible food schedules that accommodate the associated symptoms of this disease. 相似文献
5.
Baher Husain Christian Kuehne Christian Waydhas Ulrike Lewan Claudia Ose Dieter Nast-Kolb Steffen Ruchholtz 《European Journal of Trauma》2006,32(6):548-554
Abstract
Background: Does there exist a difference in the outcome of severely injured children and severely injured healthy adults?
Methods: The data of 1,566 severely injured patients, treated between May 1998 and December 2002 in our emergency department of the
University Essen/Germany, were analyzed. Patients with an injury severity score (ISS) > 24 were included in the present study.
Patients younger as 18 (17) years were located to the children group c. Patients aged 18 and up to the age of 54 were included
in the adult group a.
Results: Fifty-four children and 252 adults met the selection criteria. ISS and the Glasgow coma scale (GCS) before intubation were
not statistically different in both groups. Seriously injured children stayed significantly shorter on the intensive care
unit, required significantly less ventilator days. Furthermore, the incidence of single organ failure (SOF) and multiple organ
failure (MOF) was significantly lower in the children group. Mortality in the children group (29.6%) was lower than that in
the adult group (33.7%). There was no death due to MOF in the children group as compared to 2.4% (n = 6) in the adults.
Conclusion: The incidence of SOF and MOF was significantly lower in the children group although there was no difference in ISS, GCS and
injury patterns. The prognosis of severely injured children was found to be better than those of adults. Moreover, there was
no death due to MOF in the children group. 相似文献
6.
7.
A Decade of Change in Obesity Surgery 总被引:4,自引:0,他引:4
Edward E Mason MD PhD Shenghui Tang MS Kathleen E Renquist BS Dwight T Barnes Joseph J Cullen MD Cornelius Doherty MD James W Maher MD 《Obesity surgery》1997,7(3):189-197
Background: The International (formerly National) Bariatric Surgery Registry began collecting data in January 1986. The aim
of this study was to examine changes in the practice of surgical treatment of severe obesity that occurred during the decade
of 1986 through 1995, as observed in the IBSR data. Methods: All data submitted to the IBSR during the decade were transferred
to the IBM mainframe computer for analysis. Characteristics of operative type populations were compared over time using analysis
of variance (ANOVA) for age, body mass index (BMI), operative weight and Chi-square (χ2) test for gender. Results: There has been a steady increase over the decade in mean patient weight. The operations used have
changed from predominantly ‘simple’ operations to more frequent use of ‘complex’ operations. Within the categories of ‘simple’
and ‘complex’, an increase in the variety of operations occurred. As a group, patients with ‘simple’ operations have been
heavier, more often male and public pay patients than those who have undergone ‘complex’ operations. One year weight loss
was greater for Roux-en-Y gastric bypass (RGB) than vertical banded gastroplasty (VBG), but follow-up rates were too low to
study the relative merits of the operations used. The reported incidence of operative mortality and serious complications
(leak with peritonitis, abscess and pulmonary embolism) remained low. Conclusions: These observations and their implications
can be summarized in three statements which relate to action for improved patient care in the beginning of the new century:
(1) increasing weight of candidates for surgical treatment during this decade indicates the need for earlier use of operative
treatment before irreversible complications of obesity can develop; (2) low risk of obesity surgery, decreasing postoperative
hospital stay, and early weight control support the continued and increased use of surgical treatment; (3) continued widespread
use of both ‘simple’ and ‘complex’ operations with increased modifications of standard RGB and VBG procedures emphasizes the
need for standardized long-term data and analyses regarding both weight control and postoperative side-effects. 相似文献
8.
M. Laurin Council Jennifer M. Gardner Cynthia Helms Ying Liu Lynn A. Cornelius Anne M. Bowcock 《Experimental dermatology》2009,18(5):485-487
Abstract: The risks of developing malignant melanoma (MM) include ultraviolet irradiation and genetic factors. To examine the contribution of rare and common variation within known MM genes in sporadic US MM patients, coding regions of known MM susceptibility genes [cyclin-dependent kinase inhibitor 2A ( CDKN2A ), cyclin-dependent kinase 4, melanocortin 1 receptor ( MC1R ) and tyrosinase ( TYR )] were resequenced in 109–135 MM cases. The significance of variants was examined by comparing their frequencies in 390 cancer-free controls. Potential deleterious mutations in CDKN2A were found in two patients and two others had variants of unknown significance. Cases were more likely than controls to harbour the MC1R 'R' variants known or predicted to alter its function ( P = 0.002), particularly the R160W variant ( P = 0.0035). The associated TYR R402Q variant (rs1126809*A) was found in 29% of cases, similar to what has been described previously. One MM patient with a family history of MM, who had developed other skin cancers, was homozygous for a novel TYR variant (P406L) of unknown significance. Hence, rare variants in TYR may be important risk factors for skin cancer. 相似文献
9.
Christian Waydhas Dieter Nast-Kolb Steffen Ruchholtz 《European journal of trauma and emergency surgery》2007,33(2):170-175
Abstract
Objective: To define the diagnostic accuracy of clinical examination in patients with impaired consciousness or endotracheal intubation
to detect pelvic ring fractures and to identify those with severe bleeding.
Methods: Included in this prospective data collection with retrolective data analysis were a consecutive series of blunt trauma victims
with either a Glasgow Coma Scale ≤ 13 or tracheal intubation. Clinical examination comprised testing for stability of the
iliac wings.
Results: From 784 subjects (injury severity score 23.3 ± 17.4) 93 patients (11.9%) were found to have a pelvic ring fracture. Clinical
instability of the pelvic ring was found in 42 patients. There was only one false positive. Fifty-two fractures could not
be identified by clinical examination, including nine fractures (17%) that required surgical fracture stabilization (sensitivity
of clinical examination 44.1%). Seventeen fractures (18.3%) were associated with a blood loss larger than 20% of circulating
blood volume. Sixteen of those were identified by clinical instability of the pelvic ring (sensitivity 94.1%, specificity
97.0%, positive predictive value 38.1%, negative predictive value 99.9%).
Conclusions: Clinical examination for stability of the pelvis in this selected group of patients missed a significant number of pelvic
ring fractures including fractures that require surgical stabilization. The finding of a clinically unstable identifies most
of the patients with the pelvic ring fracture being a major source of bleeding. A stable pelvis makes pelvic ring fracture
as being the source of bleeding quite unlikely. 相似文献
10.
Sonographic evaluation of gallbladder kinetics: in vitro and in vivo comparison of different methods to assess gallbladder emptying. 总被引:3,自引:0,他引:3
Bernd Wedmann Gabriele Schmidt Martin Wegener Christoph Coenen Dieter Ricken Cornelia Drge 《Journal of clinical ultrasound : JCU》1991,19(6):341-349
In an in vitro study, 10 gallbladders of adult pigs and 6 gallbladders of lambs, all removed immediately after slaughtering, were stimulated in a water bath by electric means to induce active contraction. Gallbladder emptying was followed by ultrasonography employing five measurement procedures: (1) gallbladder width, (2) longitudinal planimetry, (3) transverse planimetry, (4) ellipsoid method, and (5) sum of cylinders method. In an in vivo investigation, gallbladder emptying of 30 volunteers (12 healthy subjects, 18 diabetics) was evaluated in the same way after ingestion of a fatty meal. Gallbladder width was found to be unsuitable to estimate the decrease in gallbladder volume due to a nonlinear relation of the parameters. Longitudinal planimetry tended to be less valid than transverse planimetry in assessing gallbladder volume reduction. The most valid estimation of gallbladder volume decreases was obtained by the two three-dimensional procedures. However, in neither in vitro nor in vivo could a significant difference between the sum of cylinders method and the ellipsoid method in determining relative volume reduction be established. We conclude that a three-dimensional measurement procedure should be used for valid assessments of gallbladder motility. However, according to our data there is no advantage in using the time-consuming sum of cylinders method compared to the simple ellipsoid method. 相似文献