全文获取类型
收费全文 | 4268篇 |
免费 | 236篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 85篇 |
儿科学 | 98篇 |
妇产科学 | 30篇 |
基础医学 | 439篇 |
口腔科学 | 66篇 |
临床医学 | 341篇 |
内科学 | 951篇 |
皮肤病学 | 75篇 |
神经病学 | 195篇 |
特种医学 | 96篇 |
外科学 | 858篇 |
综合类 | 104篇 |
一般理论 | 2篇 |
预防医学 | 184篇 |
眼科学 | 104篇 |
药学 | 458篇 |
中国医学 | 38篇 |
肿瘤学 | 396篇 |
出版年
2023年 | 20篇 |
2022年 | 67篇 |
2021年 | 151篇 |
2020年 | 84篇 |
2019年 | 136篇 |
2018年 | 140篇 |
2017年 | 111篇 |
2016年 | 95篇 |
2015年 | 107篇 |
2014年 | 161篇 |
2013年 | 200篇 |
2012年 | 297篇 |
2011年 | 346篇 |
2010年 | 166篇 |
2009年 | 150篇 |
2008年 | 251篇 |
2007年 | 256篇 |
2006年 | 259篇 |
2005年 | 239篇 |
2004年 | 188篇 |
2003年 | 181篇 |
2002年 | 190篇 |
2001年 | 92篇 |
2000年 | 102篇 |
1999年 | 91篇 |
1998年 | 34篇 |
1997年 | 30篇 |
1996年 | 27篇 |
1995年 | 18篇 |
1994年 | 17篇 |
1993年 | 21篇 |
1992年 | 35篇 |
1991年 | 33篇 |
1990年 | 27篇 |
1989年 | 27篇 |
1988年 | 21篇 |
1987年 | 29篇 |
1986年 | 17篇 |
1985年 | 20篇 |
1984年 | 12篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1974年 | 6篇 |
1973年 | 5篇 |
1968年 | 4篇 |
1957年 | 2篇 |
排序方式: 共有4520条查询结果,搜索用时 15 毫秒
1.
Madan M. Rehani Emily R. Melick Raza M. Alvi Ruhani Doda Khera Salma Batool-Anwar Tomas G. Neilan Michael Bettmann 《European radiology》2020,30(4):1839-1846
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria. 相似文献
2.
3.
Waseem Raza Hafiza Anum Mohy-u-Din Sajid Shaeen Malik Iqra Manzoor Baby Nadeem 《Ultrasound in medicine & biology》2019,45(1):21-25
The objective of the study was to evaluate the reliability of sonoelastography in ductal carcinoma in patients in primary and secondary health care settings. Google Scholar, PubMed, Medline, Medscape, Wikipedia and NCBI were searched in January 2018 for all original research and review articles to identify relevant studies. Two reviewers selected the articles independently for based on the title and abstract. The selection criteria were sonoelastography accuracy for diagnosing ductal carcinoma as index text, B-mode sonography, and micropure imaging; surgery and histologic findings were used as reference text; and benign and malignant breast abnormalities and ductal carcinoma were used as target conditions. Two reviewers extracted the data on selected study characteristics, and the results were used to construct the tables and figures. Fifteen studies on ductal carcinoma were found. The overall sensitivity of sonoelastography in diagnosing ductal carcinoma was 85.7%, and the specificity, 79.8%. On the basis of the literature review, it was concluded that sonoelastography has high sensitivity and specificity in diagnosing ductal carcinoma. 相似文献
4.
5.
A. Zeevi S. Husain K. J. Spichty K. Raza J. B. Woodcock D. Zaldonis L. M. Carruth R. J. Kowalski J. A. Britz K. R. McCurry 《American journal of transplantation》2007,7(2):471-475
Profound T-cell depletion with the monoclonal antibody alemtuzumab facilitates reduced maintenance immunosuppression in abdominal and lung transplantation. While the phenotype of the post-depletional T cells has been characterized, little is known about their function. In the present study, global and CMV-specific T-cell function was assessed longitudinally in 23 lung transplant (LTx) recipients using T-cell assays (ImmuKnow and T Cell Memory, Cylex, Columbia, MD) during the first year posttransplant after induction therapy. Recovery of mitogen responses were seen at 2 weeks posttransplantation (65%PHA; 58% Con A), despite the low number of circulating T cells (<2%). These responses declined at 4-5 months (24%PHA; 54% Con A) and were partially reconstituted by 9 months (46% PHA; 73% Con A). CMV-specific responses recovered in 80% of R+ patients as early as 2 weeks posttransplant (n = 5) and 72% of patients had a memory response by 3 months (n = 11). In contrast, only 2 of 5 patients who did not exhibit memory responses pre-transplant (R-) developed transient CMV-specific T-cell responses. Our results show that profound depletion of T cells induced by alemtuzumab spares the functional subset of CMV-specific memory T cells. Conversely, CMV R- patients predepletion may require a prolonged period of prophylaxis. 相似文献
6.
Camphor and m-cresol mixtures are used in antiseptic and anti-itching creams. No compendial method exists for these preparations. This paper reports a capillary gas chromatographic method using FID detection with 2,6-di-tert-butyl-4-methylphenol as internal standard on a 30 m×0.32 mm Supelcowax®-10 column (0.25 μm film) with helium as carrier gas. Ramped temperature programming was applied. The method allows simultaneous quantitation of camphor and m-cresol in the presence of o- and p-cresols, calamine and zinc oxide. Overall percent recoveries (±SD, n=9) of camphor, o-, p- and m-cresol from spiked placebo creams, at a labeled amount of 10 (w/w)% were 96.9±0.6, 98.2±0.6, 99.2±0.5 and 101.0±0.9%, respectively, and at a labeled amount of 1% were 96.7±0.6, 97.8±0.9, 97.8±0.6, and 100.3±1.0%, respectively. The recovery studies were carried out at ±30% of the labeled amounts. Linear peak area or height ratios were obtained (r>0.999) for camphor, o-, p- and m-cresol covering a concentration range of 10–200% of the labeled amount. Linearity (r>0.999) was also obtained for m-cresol when the relative concentration of o- and p-cresol was varied from 5 to 100% of the m-cresol concentration. The resolution between the ‘critical pair’ of p- and m-cresol was ≥1.1. The limit of quantitation was 23 pg for m-cresol and 9.3 pg for camphor using an injection split of 1:50. The repeatability (%RSD) for all compounds were <2% for peak area and <1.4% for peak height ratios. System suitability and robustness of the method were established. The method was successively applied to the assay of available commercial products and allows assay of camphor and the three cresol isomers. 相似文献
7.
8.
Betina N?rager Mirza Husic Jacob E M?ller Kenneth Egstrup 《Journal of the American Society of Echocardiography》2004,17(7):732-738
BACKGROUND: Wall-motion analysis during low-dose dobutamine echocardiography (LDDE) is a semiquantitative measure of left ventricular contractile reserve after myocardial infarction (MI). The Doppler echocardiographic myocardial performance index (MPI) is a quantitative measure of combined left ventricular systolic and diastolic function. We sought to characterize the changes in MPI during LDDE in control subjects and patients with MI, and to describe the relation of these changes to changes in regional systolic function. METHODS: MPI was obtained at rest and during LDDE (10 microg/kg/min) in 25 healthy volunteers (group 1) and 50 patients with a recent MI. Patients were divided into two subsets; those with (n = 23; group 2A) and those without (n = 27; group 2B) a contractile reserve defined as an improvement of wall motion in more than two contiguous infarct-zone segments during LDDE. DeltaMPI was defined as the change from rest to LDDE. RESULTS: MPI decreased significantly during LDDE in groups 1 and 2A, whereas MPI increased in group 2B (DeltaMPI = 0.12 +/- 0.04 and 0.10 +/- 0.08 vs -0.03 +/- 0.08, P <.0001). On multivariate analysis, Deltawall-motion score index predicted DeltaMPI (beta = 0.65, P <.0001) independently of age, sex, and the dobutamine-induced change in heart rate and systolic blood pressure. CONCLUSIONS: Data suggest that the change in MPI during LDDE may provide a simple and quantitative measure of overall left ventricular functional reserve in patients with a recent MI. 相似文献
9.
Kulbir S. Walia MD ; Daniel E. Muser MD ; Shariq S. Raza MD ; Tricia Griech MSPT ; Yasin N. Khan MD 《Pain practice》2004,4(4):303-306
Abstract: We present a case of a 13-year-old boy who developed signs and symptoms of neuropathic pain/early Complex Regional Pain Syndrome (CRPS) Type I, formerly known as Reflex Sympathetic Dystrophy (RSD), after spraining his ankle while wrestling. Aggressive pain control, using medications and sympatholytic blocks, with physical therapy and rehabilitation, led to the resolution of his painful condition. This prevented the disease from possibly progressing to a full-blown case of CRPS I (RSD) that is very challenging to treat. 相似文献
10.
OBJECTIVE--To identify prognostic factors in a consecutive series of patients with bleeding oesophageal varices and develop an optimum regimen of treatment. DESIGN--Retrospective review. SETTING--I Department of Surgery, University Hospital, Vienna, Austria. PATIENTS--301 consecutive patients with bleeding oesophageal varices. OUTCOME MEASURES--Median survival and survival at one year after sclerotherapy alone (n = 213), or sclerotherapy with portosystemic shunt (n = 54), Hassab's devascularisation (n = 29), or liver transplantation (n = 5). RESULTS--Prognosis was dependent on the severity of liver damage at the start of treatment. Median survival for Child's class A was 47 months, for Child's class B 54 months, and for Child's class C 2 months. The overall one year survival for patients in Child's class C was 33%, for sclerotherapy alone 28%, and for sclerotherapy and portosystemic shunt 42%, Hassab's devascularisation 50%, and liver transplantation 80%. CONCLUSION--Despite the small number of patients who underwent liver transplantation and their poor initial prognosis (Child's class C, n = 4; class B, n = 1) our results suggest that liver transplantation should be considered for the treatment of patients with end stage cirrhosis and bleeding varices. 相似文献