全文获取类型
收费全文 | 18559篇 |
免费 | 1402篇 |
国内免费 | 77篇 |
专业分类
耳鼻咽喉 | 161篇 |
儿科学 | 351篇 |
妇产科学 | 255篇 |
基础医学 | 2509篇 |
口腔科学 | 553篇 |
临床医学 | 1917篇 |
内科学 | 3714篇 |
皮肤病学 | 277篇 |
神经病学 | 1724篇 |
特种医学 | 1103篇 |
外科学 | 2839篇 |
综合类 | 233篇 |
一般理论 | 16篇 |
预防医学 | 1313篇 |
眼科学 | 516篇 |
药学 | 1091篇 |
中国医学 | 20篇 |
肿瘤学 | 1446篇 |
出版年
2023年 | 139篇 |
2022年 | 248篇 |
2021年 | 519篇 |
2020年 | 322篇 |
2019年 | 420篇 |
2018年 | 474篇 |
2017年 | 362篇 |
2016年 | 399篇 |
2015年 | 522篇 |
2014年 | 698篇 |
2013年 | 848篇 |
2012年 | 1376篇 |
2011年 | 1399篇 |
2010年 | 812篇 |
2009年 | 776篇 |
2008年 | 1169篇 |
2007年 | 1231篇 |
2006年 | 1070篇 |
2005年 | 988篇 |
2004年 | 949篇 |
2003年 | 837篇 |
2002年 | 689篇 |
2001年 | 313篇 |
2000年 | 300篇 |
1999年 | 254篇 |
1998年 | 165篇 |
1997年 | 120篇 |
1996年 | 97篇 |
1995年 | 82篇 |
1994年 | 72篇 |
1993年 | 74篇 |
1992年 | 138篇 |
1991年 | 154篇 |
1990年 | 131篇 |
1989年 | 115篇 |
1988年 | 109篇 |
1987年 | 112篇 |
1986年 | 90篇 |
1985年 | 97篇 |
1984年 | 114篇 |
1983年 | 71篇 |
1982年 | 74篇 |
1981年 | 57篇 |
1980年 | 54篇 |
1979年 | 109篇 |
1978年 | 78篇 |
1977年 | 74篇 |
1976年 | 57篇 |
1971年 | 52篇 |
1969年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Dr. Heinrich Dickel Otto Blome Karl-Heinz Hagemann Hans Joachim Schwanitz Oliver Kuss Swen Malte John 《Trauma und Berufskrankheit》2003,5(1):109-118
The dermatologist's procedure was introduced in 1972 by employers' liability insurance funds in the industrial, agricultural and public sectors of Germany's statutory occupational accident insurance as a "procedure for early detection of occupational skin diseases". So far, it is still the most relevant tool for secondary prevention in occupational dermatology in Germany. According to the intention of this procedure, insured persons with a skin disease in which an occupational aetiology is suspected must be offered preventive measures and, if necessary, given appropriate treatment to avoid their losing their jobs. On the initiative of the Central Federation of Industrial Professional Associations (HVBG), a study group was set up in 1999 from among its membership in cooperation with the Working Committee of Occupational and Environmental Dermatology (ABD) and the Professional Organisation of German Dermatologists (BVDD) to improve on the efficiency of the "classic" dermatologist's procedure. The proposed "optimised" dermatologist's procedure is based on the assumption that early detection followed by competent and intensified skin protection and skin care will be successful in retarding or stopping the progression of occupational dermatoses, while later treatment is likely to be less effective. In October 2002, a pilot study started in Northwest Germany to establish by scientific evaluation whether the implementation of secondary protective measures is definitively better when the provisional "optimised" dermatologist's procedure is followed. The study results should allow detailed suggestions for an improved dermatologist's procedure before it is introduced nationwide. 相似文献
12.
This retrospective analysis reviews the clinical experience of a major urban referral hospital with diffuse malignant pleural mesothelioma during the 14-year period from 1973 through 1986. Seventy-five cases of definite or equivocal mesothelioma were identified. There were four cases of primary malignant peritoneal mesothelioma, seven cases of benign fibrous mesothelioma, and 64 cases of diffuse malignant pleural mesothelioma. In 43 cases (67%) of diffuse malignant pleural mesothelioma, there was historic evidence of asbestos exposure. In 21 cases (33%), there was no known history of asbestos exposure. An increase in annual incidence of diffuse malignant pleural mesothelioma was observed over the study period, from three cases in 1973 to ten cases in 1986. Despite greater awareness of this disease, the diagnosis remains a difficult one to establish given the nonspecific symptoms, signs and radiographic appearance, variable histologic appearance, and poor diagnostic sensitivity and specificity of thoracentesis and closed pleural biopsy. Thoracotomy, thoracoscopy, and CT-guided needle biopsies gave higher yields and are the diagnostic measures of choice when diffuse malignant pleural mesothelioma is suspected. 相似文献
13.
14.
Jeffrey T Cope MD Michael C Mauney MD David Banks BS Oliver A.R Binns MD Christopher L Moore BS Jeffrey J Rentz BS Kimberly S Shockey MS R.Christoper King MD Irving L Kron MD Curtis G Tribble MD 《The Annals of thoracic surgery》1997,63(6)
Background. Hypoxia and warm ischemia produce severe injury to cardiac grafts harvested from non–heart-beating donors. To potentially improve recovery of such grafts, we studied the effects of intravenous phenylephrine preconditioning.Methods. Thirty-seven blood-perfused rabbit hearts were studied. Three groups of non–heart-beating donors underwent intravenous treatment with phenylephrine at 12.5 (n = 8), 25 (n = 7), or 50 μg/kg (n = 7) before initiation of apnea. Non–heart-beating controls (n = 8) received saline vehicle. Hypoxic cardiac arrest occurred after 6 to 12 minutes of apnea, followed by 20 minutes of warm in vivo ischemia. A 45-minute period of ex vivo reperfusion ensued. Nonischemic controls (n = 7) were perfused without antecedent hypoxia or ischemia.Results. Phenylephrine 25 μg/kg significantly delayed the onset of hypoxic cardiac arrest compared with saline controls (9.6 ± 0.5 versus 7.7 ± 0.4 minutes; p = 0.00001), yet improved recovery of left ventricular developed pressure compared with saline controls (57.1 ± 5.3 versus 41.0 ± 3.4 mm Hg; p = 0.04). Phenylephrine 25 μg/kg also yielded a trend toward less myocardial edema than saline vehicle (p = 0.09).Conclusions. Functional recovery of nonbeating cardiac grafts is improved by preconditioning. We provide evidence that the myocardium can be preconditioned with phenylephrine against hypoxic cardiac arrest.(Ann Thorac Surg 1997;63:1664–8) 相似文献
15.
Cynthia S. Pomerleau Anne W. Garcia Ovide F. Pomerleau Oliver G. Cameron 《Psychoneuroendocrinology》1992,17(6):627-638
Nicotine intake, menstrual and smoking withdrawal symptomatology, and baseline cortisol and MHPG were assessed in nine women smokers under conditions of ad lib smoking and overnight abstinence in three menstrual phases (early follicular, mid-to-late follicular, and late luteal). A trend towards higher nicotine intake p <0.100 was observed in the mid-to-late follicular phase. Although me menstrual symptomatology was not significantly elevated during the smoking abstinence condition overall, abstinence appeared to prevent the normal reduction in symptomatology during the mid-to-late follicular phase that occurred under conditions of ad lib smoking. Menstrual and withdrawal symptoms were highly correlated, and both were most pronounced during the late luteal/abstinence condition. The smoking-specific item “craving” reflected this pattern, though in attenuated form, suggesting that the observed exacerbation of withdrawal symptomatology was not simply due to generalized dysphoria, as queried in both instruments. MHPG was significantly elevated in the late luteal phase, whereas cortisol was significantly higher during ad lib smoking than during abstinence and tended to be highest in the mid-to-late follicular phase. Further investigation will be needed to determine the functional significance of these findings for understanding and treating smoking in women. 相似文献
16.
17.
The cattle major histocompatibility complex (MHC) class II DR gene product is a heterodimer encoded by the BoLA-DRA and -DRB3 genes. Several groups have isolated cDNA and genomic clones for these genes, but their full genomic organization has not been described. We used a combination of long-range polymerase chain reaction (PCR), cloning and sequencing to define the organization of the DRB3 gene on existing genomic clones and in genomic DNA. We estimate the size of the coding region to be 11.4 kbp. Sequencing of full-length PCR clones from two different haplotypes confirmed that they carried complete DRB3 genes and allowed the design of probes and primers to isolate and characterize the DRB3 promoter and 3' end. Fragments carrying the 5' end of the DRB3 gene and its promoter were identified on bacterial artificial chromosome (BAC) clones carrying the BoLA-DR genes. A 10-kbp promoter fragment was subcloned from one clone and a 1.7-kbp region including exon 1 and the promoter was sequenced. A 3-kbp fragment encoding exons 4-6 and the entire 3' untranslated region of the DRB3 gene was isolated from lambda clone A1 and sequenced. This provides us with improved characterization of the DRB3*0101 and DRB3*2002 alleles, and also subcloned 5' and 3' flanking regions of the polymorphic DRB3 gene for use in functional studies. 相似文献
18.
19.
20.