全文获取类型
收费全文 | 48152篇 |
免费 | 4016篇 |
国内免费 | 115篇 |
专业分类
耳鼻咽喉 | 379篇 |
儿科学 | 1913篇 |
妇产科学 | 1327篇 |
基础医学 | 6938篇 |
口腔科学 | 969篇 |
临床医学 | 6814篇 |
内科学 | 9313篇 |
皮肤病学 | 915篇 |
神经病学 | 5012篇 |
特种医学 | 1099篇 |
外科学 | 4214篇 |
综合类 | 409篇 |
一般理论 | 62篇 |
预防医学 | 5816篇 |
眼科学 | 680篇 |
药学 | 2785篇 |
2篇 | |
中国医学 | 54篇 |
肿瘤学 | 3582篇 |
出版年
2023年 | 406篇 |
2022年 | 498篇 |
2021年 | 1283篇 |
2020年 | 956篇 |
2019年 | 1426篇 |
2018年 | 1550篇 |
2017年 | 1223篇 |
2016年 | 1349篇 |
2015年 | 1418篇 |
2014年 | 1812篇 |
2013年 | 2693篇 |
2012年 | 3742篇 |
2011年 | 3863篇 |
2010年 | 2105篇 |
2009年 | 1870篇 |
2008年 | 3096篇 |
2007年 | 3177篇 |
2006年 | 3141篇 |
2005年 | 2956篇 |
2004年 | 2857篇 |
2003年 | 2623篇 |
2002年 | 2355篇 |
2001年 | 410篇 |
2000年 | 309篇 |
1999年 | 352篇 |
1998年 | 543篇 |
1997年 | 406篇 |
1996年 | 373篇 |
1995年 | 352篇 |
1994年 | 283篇 |
1993年 | 273篇 |
1992年 | 213篇 |
1991年 | 176篇 |
1990年 | 166篇 |
1989年 | 128篇 |
1988年 | 152篇 |
1987年 | 110篇 |
1986年 | 116篇 |
1985年 | 114篇 |
1984年 | 116篇 |
1983年 | 108篇 |
1982年 | 139篇 |
1981年 | 133篇 |
1980年 | 112篇 |
1979年 | 73篇 |
1978年 | 74篇 |
1977年 | 54篇 |
1976年 | 55篇 |
1975年 | 47篇 |
1972年 | 50篇 |
排序方式: 共有10000条查询结果,搜索用时 546 毫秒
81.
82.
Joseph Cofrancesco Nina Shah Khalil G Ghanem Adrian S Dobs Robert S Klein Kenneth Mayer Paula Schuman David Vlahov Anne M Rompalo 《Gynecological endocrinology》2006,22(5):244-251
Drug use and HIV infection may affect sex hormone levels in women. One hundred and ninety-six women with and without a history of illicit drug use (50 HIV-negative and 148 HIV-infected), with regular menses, who never used antiretrovirals, were evaluated. Luteinizing hormone levels were significantly higher in women with a CD4 cell count <200/microl (p < 0.002). Current methadone use was associated with lower levels of total testosterone (p = 0.03) and higher levels of prolactin (p = 0.002); mean estradiol levels were 43% lower in women who used intravenous drugs (p < 0.001). Alcohol and crack cocaine use was not associated with sex hormone levels. Age, race, body mass index and degree of HIV immunosuppression were also associated with differences in sex hormone levels. 相似文献
83.
Alan A Arslan Anne Zeleniuch-Jacquotte Annekatrin Lukanova Yelena Afanasyeva Joseph Katz Mortimer Levitz Giuseppe Del Priore Paolo Toniolo 《Cancer epidemiology, biomarkers & prevention》2006,15(11):2123-2130
Epidemiologic evidence suggests that a full-term pregnancy may affect maternal risk of breast cancer later in life. The objective of this cross-sectional study was to compare circulating levels of maternal hormones affecting breast differentiation (human chorionic gonadotropin and prolactin) and proliferation [alpha-fetoprotein, insulin-like growth factor I (IGF-I), and estradiol] between women at a low to moderate risk (Asians and Hispanics), as compared with women at a high risk for breast cancer (Caucasians and African-Americans). Between May 2002 and December 2004, a total of 586 pregnant women were approached during a routine prenatal visit. Among them, 450 women (206 Caucasian, 126 Asian, 88 Hispanic, and 30 African-American) met the inclusion criteria and signed the informed consent. Only singleton pregnancies were considered. Blood samples were drawn during the second trimester of pregnancy. Laboratory analyses were done using the IMMULITE 2000 immunoassay system. Gestational age standardized mean levels of estradiol, IGF-I, and prolactin were significantly higher in Hispanic women compared with Caucasian women. Mean concentration of IGF-I was significantly higher in African-American women compared with Caucasian and Asian women. No significant differences in pregnancy hormone levels were observed between Caucasian and Asian (predominantly second-generation Chinese) women in this study. Irrespective of ethnicity, women who had their first pregnancy had substantially higher mean levels of alpha-fetoprotein, human chorionic gonadotropin, estradiol, and prolactin compared with women who previously had at least one full-term pregnancy. These data suggest that circulating pregnancy hormone levels may explain some of the ethnic differences in breast cancer risk. 相似文献
84.
85.
Diagnosis of somatisation: effect of an educational intervention in a cluster randomised controlled trial. 下载免费PDF全文
Marianne Rosendal Flemming Bro Per Fink Kaj Sparle Christensen Frede Olesen 《The British journal of general practice》2003,53(497):917-922
BACKGROUND: Somatisation is highly prevalent in primary care (present in 25% of visiting patients) but often goes unrecognised. Non-recognition may lead to ineffective treatment, risk of iatrogenic harm, and excessive use of healthcare services. AIM: To examine the effect of training on diagnosis of somatisation in routine clinical practice by general practitioners (GPs). DESIGN OF STUDY: Cluster randomised controlled trial, with practices as the randomisation unit. SETTING: Twenty-seven general practices (with a total of 43 GPs) in Vejle County, Denmark. METHOD: Intervention consisted of a multifaceted training programme (the TERM [The Extended Reattribution and Management] model). Patients were enrolled consecutively over a period of 13 working days. Psychiatric morbidity was assessed by means of a screening questionnaire. GPs categorised their diagnoses in another questionnaire. The primary outcome was GP diagnosis of somatisation and agreement with the screening questionnaire. RESULTS: GPs diagnosed somatisation less frequently than had previously been observed, but there was substantial variation between GPs. The difference between groups in the number of diagnoses of somatisation failed to reach the 5% significance (P = 0.094). However, the rate of diagnoses of medically unexplained physical symptoms was twice as high in the intervention group as in the control group (7.7% and 3.9%, respectively, P = 0.007). Examination of the agreement between GPs' diagnoses and the screening questionnaire revealed no significant difference between groups. CONCLUSION: Brief training increased GPs' awareness of medically unexplained physical symptoms. Diagnostic accuracy according to a screening questionnaire remained unaffected but was difficult to evaluate, as there is no agreement on a gold standard for somatisation in general practice. 相似文献
86.
87.
Julien Fey André Dietrich Anne Cosset T. Desprez L. Maréchal-Drouard 《Current genetics》1997,32(5):358-360
Two identical “chloroplast-like” tRNAAsn genes, trnN1 and trnN2, have been identified in the potato (Solanum tuberosum) mitochondrial genome. The flanking sequences of trnN1 are unrelated to the corresponding authentic potato chloroplast regions, whilst those of trnN2 are very similar to the chloroplast sequences. The trnN1 copy is present in the mitochondrial genome of various plants whereas the second copy, trnN2, is absent from all the other plant genomes studied so far. Interestingly, both trnN copies are expressed in potato mitochondria. Sequences flanking the chloroplast-like tRNAHis gene (trnH), present as a single copy in the potato mitochondrial DNA, are unrelated to the corresponding chloroplast sequences, whereas
chloroplast-derived sequences have been maintained in the vicinity of the maize chloroplast-like mitochondrial trnH gene. However, both the potato and the maize trnH are expressed in mitochondria.
Received: 10 April / 1 August 1997 相似文献
88.
89.
In this study, ethnographic interviews were used to identify first-time fathers' experiences of the birth of their first child. Fourteen fathers were interviewed, and prenatal expectations of the experience are compared with the fathers' perceptions after the birth. Although the fathers expected to be treated as part of a laboring couple, they found that they were relegated to a supporting role. Initially the fathers were confident of their ability to support their wives, but they found that labor was more work than they had anticipated. They became fearful of the outcome, but hid these fears from their partners. Later, they found that their focus moved from their wives to their babies at the time of birth. The men all completed the experience with an enhanced respect for their wives. Fathers should be included in labor management plans and need support for their role as coach, particularly when their wives experience pain. They also need to be encouraged to eat and take a break from their wives' labor when appropriate. 相似文献
90.
Emmanuel Ellie Anne Vital Andreas Steck Jean-Michel Boiron Claude Vital Jean Julien 《Journal of neurology》1996,243(1):34-43
We studied 33 patients presenting with a peripheral neuropathy associated with non-malignant anti-myelin-associated glycoprotein (MAG) IgM monoclonal gammopathy (MG) in an attempt to delineate their clinical, immunological, electrophysiological and pathological characteristics; we also reviewed our experience concerning long-term follow-up and therapy. Peripheral neuropathy associated with non-malignant anti-MAG IgM MG was observed mostly in males (sex ratio 7.2), and mean age at onset was 67 years (range 46–81). A predominantly sensory pattern was noted in more than 80% of cases, although some patients were affected by a predominantly motor peripheral neuropathy. Although disease progression was slow in most cases, 45% of patients suffered severe disability, and in 2 cases, the patient's death appeared to stem directly from the neuropathy. The electrophysiological findings were indicative of a demyelinating process in 90% of cases, and electron microscopic examination of nerve biopsy specimens demonstrated widening of the myelin lamellae in more than 95% of cases. Most of our patients showed a disappointing response to steroids and chemotherapy or plasma exchanges. Intravenous immune globulin, evaluated in 17 patients, had a transient, mostly subjective effect in 35% and led to a clear-cut improvement in 24% of cases. We did not observe any correlation between the severity of the clinical picture and the anti-sulphoglucuronyl paragloboside antibody titre; in individual cases, clinical improvement occurred without lowering of IgM levels. Although the severity and the rate of progression may greatly vary from patient to patient, the combination of clinical, electrophysiological and pathological features delineates a characteristic pattern in peripheral neuropathy associated with non-malignant anti-MAG IgM MG. 相似文献