全文获取类型
收费全文 | 62711篇 |
免费 | 5295篇 |
国内免费 | 143篇 |
专业分类
耳鼻咽喉 | 584篇 |
儿科学 | 2461篇 |
妇产科学 | 1793篇 |
基础医学 | 8961篇 |
口腔科学 | 1273篇 |
临床医学 | 8668篇 |
内科学 | 11937篇 |
皮肤病学 | 1125篇 |
神经病学 | 6313篇 |
特种医学 | 1545篇 |
外国民族医学 | 1篇 |
外科学 | 6036篇 |
综合类 | 768篇 |
一般理论 | 75篇 |
预防医学 | 7364篇 |
眼科学 | 1011篇 |
药学 | 3681篇 |
2篇 | |
中国医学 | 75篇 |
肿瘤学 | 4476篇 |
出版年
2023年 | 497篇 |
2022年 | 716篇 |
2021年 | 1529篇 |
2020年 | 1122篇 |
2019年 | 1659篇 |
2018年 | 1868篇 |
2017年 | 1459篇 |
2016年 | 1616篇 |
2015年 | 1670篇 |
2014年 | 2215篇 |
2013年 | 3236篇 |
2012年 | 4501篇 |
2011年 | 4558篇 |
2010年 | 2505篇 |
2009年 | 2257篇 |
2008年 | 3750篇 |
2007年 | 3851篇 |
2006年 | 3806篇 |
2005年 | 3627篇 |
2004年 | 3430篇 |
2003年 | 3159篇 |
2002年 | 2890篇 |
2001年 | 802篇 |
2000年 | 681篇 |
1999年 | 715篇 |
1998年 | 680篇 |
1997年 | 549篇 |
1996年 | 473篇 |
1995年 | 467篇 |
1994年 | 398篇 |
1993年 | 373篇 |
1992年 | 483篇 |
1991年 | 449篇 |
1990年 | 425篇 |
1989年 | 352篇 |
1988年 | 381篇 |
1987年 | 347篇 |
1986年 | 359篇 |
1985年 | 331篇 |
1984年 | 293篇 |
1983年 | 287篇 |
1982年 | 258篇 |
1981年 | 256篇 |
1980年 | 215篇 |
1979年 | 265篇 |
1978年 | 211篇 |
1977年 | 166篇 |
1976年 | 177篇 |
1975年 | 169篇 |
1974年 | 190篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
141.
T Nagai Y Sugita M Kurihara T Ikeda M Rose 《Experimental and clinical immunogenetics》1991,8(2):115-118
We studied a random sample of Japanese and compared both Japanese and German monocyte antigen frequencies and performed a segregation analysis in Japanese families. In Japanese, the following gene frequencies were established: 0.1033 for HMA-A1; 0.0299 for HMA-A3; 0.0033 for HMA-A6; 0.1521 for HMA-B2. Data on the gene frequency in Germans were presented by Rose. In this comparison, the frequency for HMA-B2 in Japanese is more than two times higher; for antigen HMA-A6, the Japanese is a fifth of the German quantity. The antigen HMA-B4 was not found in Japanese. The results we obtained from family analysis confirmed an unambiguous autosomal, codominant inheritance of the examined HMA antigens. 相似文献
142.
Doris Chibo Anne Mijch Richard Doherty Christopher Birch 《Journal of clinical virology》2002,25(2):165-170
BACKGROUND: Mutations in the thymidine kinase (TK) and DNA polymerase (pol) genes of herpes simplex virus (HSV) may confer resistance to antiviral drugs, particularly in the context of immunosuppression induced by infection with the human immunodeficiency virus (HIV). OBJECTIVES: To characterise the HSV type 2 (HSV-2) TK and DNA pol genes in an immunocompromised patient with clinical resistance to both acyclovir and foscarnet. STUDY DESIGN: The TK and DNA pol genes of isolates obtained over a 2-year period from an AIDS patient with severe genital herpes infection were characterised both phenotypically and genotypically. RESULTS: HSV strains that were acyclovir resistant/foscarnet sensitive, acyclovir sensitive/foscarnet sensitive and acyclovir resistant/foscarnet resistant were isolated during this time. The TK gene of all the acyclovir resistant isolates contained a large 969 bp deletion which extended into a downstream untranslated region. The foscarnet resistance was associated with an S725G mutation in a conserved region (region II) of the herpesvirus DNA pol gene. CONCLUSIONS: Clinical and virological suppression of the infection was not always associated with subsequent reactivation with wild-type virus. Mutations of the nature we describe have not previously been reported occurring simultaneously in HSV strains isolated from patients treated with acyclovir and foscarnet. 相似文献
143.
144.
Jean-Fran?ois Ghersi-Egea Nathalie Strazielle Audrey Murat Anne Jouvet Annie Buénerd Marie-Fran?oise Belin 《Journal of cerebral blood flow and metabolism》2006,26(9):1165-1175
The choroid plexuses (CPs) form a protective interface between the blood and the ventricular cerebrospinal fluid (CSF). To probe into the pathways by which CPs provide brain protection, we sought to evaluate the efficiency of glutathione conjugation in this barrier as a mechanism to prevent the entry of blood-borne electrophilic, potentially toxic compounds into the CSF, and we investigated the fate of the resulting metabolites. Rat CPs, as well as human CPs from both fetal and adult brains, displayed high glutathione-S-transferase activities. Using an in vitro model of the blood-CSF barrier consisting of choroidal epithelial cells cultured in a two-chambered device, we showed that glutathione conjugation can efficiently prevent the entry of 1-chloro-2,4-dinitrobenzene (CDNB) into the CSF, a model for electrophilic compounds. The duration of this enzymatic protection was set by the concentration of CDNB to which the epithelium was exposed, and this barrier effect was impaired only on severe epithelial intracellular glutathione and cysteine depletion. The conjugate was excreted from the choroidal cells in a polarized manner, mostly at the blood-facing membrane, via a high-capacity transport process, which is not a rate-limiting step in this detoxification pathway, and which may involve transporters of the ATP-binding cassette c(Abcc) and/or solute carrier 21 (Slc21) families. Supplying the choroidal epithelium at the blood-facing membrane with a therapeutically relevant concentration of N-acetylcysteine sustained this neuroprotective effect. Thus, glutathione conjugation at the CP epithelium coupled with the basolateral efflux of the resulting metabolites form an efficient blood-CSF enzymatic barrier, which can be enhanced by pharmacologically increasing glutathione synthesis within the epithelial cells. 相似文献
145.
146.
L H Lin S Bock K Carpenter M Rose J J Norden 《Brain research. Molecular brain research》1992,14(1-2):147-153
Metabolic labeling and quantitative 2D gel autoradiography were used to assess changes in the synthesis and transport of GAP-43 in entorhinal cortex (EC) neurons and perforant pathway during lesion-induced sprouting and reactive synaptogenesis. In normal adult rats, there is a high constitutive level of GAP-43 synthesis and transport in EC neurons projecting to the hippocampus. Following unilateral EC lesions, there is a 2-fold (100%) increase in the transport of newly synthesized GAP-43 to the contralateral or 'sprouting' hippocampus. The timing of this upregulation (between 6 and 15 days) suggests that changes in GAP-43 expression occur in response to the growth of presynaptic terminals during sprouting. 相似文献
147.
148.
Jean-Marie Boeynaems Anne De Leener Barbara Dessars Hector Rodriguez Villa-Lobos Jean-Claude Aubry Frédéric Cotton Philippe Thiry 《Clinical chemistry and laboratory medicine》2004,42(1):67-71
Polyethylene terephthalate (PET) tubes have several advantages over glass tubes: they are unbreakable, lighter and more easily disposed of. Despite a steady increase in their use and an expansion of the range of available tubes, few studies validating their use have been published in the literature. This paper describes the various studies that have been performed to compare VENOJECT glass, VENOSAFE PET and VENOSAFE PET/heparin tubes for the assay of a panel of analytes in routine clinical chemistry, immunochemistry, hormone and tumor marker analysis and trace metal determination. These studies demonstrate that VENOSAFE PET tubes are a suitable alternative to glass tubes. 相似文献
149.
Hans Rostad Anne Naalsund Randi Jacobsen Trond Eirik Strand Helge Scott Erik Heyerdahl Str?m Jarle Norstein 《European journal of cardio-thoracic surgery》2004,26(4):782-786
OBJECTIVE: The final outcome of patients with small cell lung cancer (SCLC) is poor with an overall 5-year survival rate of less than 10%. Therefore, the question of surgery in patients with a technically-operable solitary tumor has been raised. The purpose of this study was to identify the proportion of patients with operable SCLC and to assess the prognosis of different treatment strategies. For patients who were operated, we compared the resection specimens from patients with more than 5-year survival with those with shorter survival to see whether the specimens belonged to different subclasses of SCLC. METHODS: In Norway all clinical and pathologic departments submit reports on cancer patients to the Cancer Registry. The Registry also has a law-regulated authority to collect supplemental information regarding diagnosis, treatment and outcome for all cancer patients from the hospitals in charge. All reports on patients diagnosed as having SCLC in limited disease or unknown stage during the time interval 1993-1999 were reviewed. Patients with a T2-tumor, in whom a pneumonectomy would have to be performed, were classified as potentially operable. Five-year relative survival was calculated for patients diagnosed in 1993-1997. RESULTS: During the actual period 2442 individuals with SCLC were identified. The majority was treated with conventional chemotherapy or concurrent chemoradiotherapy while 38 underwent surgical therapy. Following reclassification of 697 patients reported to have limited disease or unknown stage 180 were judged to be in stage I. In addition to the 38 resected patients 14 were considered fit for surgery technically and medically while 97 were found to be potentially operable treatment modalities apart from surgery yielded a 5-year survival rate <7%. For stage I (N=96) the rate was 11.3% in conventionally treated patients compared to 44.9% for those who underwent surgical resection. By pathological review of surgical specimens a diagnosis of SCLC was confirmed in all patients treated by surgery in the groups with long and short survival. CONCLUSION: This investigation demonstrates that patients with SCLC having a peripherally located tumor should be referred to surgery, as long time survival is far better than for conventionally treated patients. 相似文献
150.
BACKGROUND: Classification of patients with chronic whiplash associated disorders (WAD) into homogenous subgroups is an important objective in order to tailor interventions and to control for subgroup differences when evaluating treatment outcome. AIMS: The aims of this study were to investigate if it was possible to replicate and describe the three cluster solution and profiles found in other pain groups and describe cluster profiles based on self-reported Multidimensional Pain Inventory-scores for patients with WAD three months after the injury, describe characteristics of the clusters in relation to disability, self-efficacy and coping at the same point in time and to validate the cluster solution by comparing clusters in disability, self-efficacy and coping over time. METHODS: Ninety-one WAD-patients three months after the accident took part in the study. The measures used were the Multidimensional Pain Inventory-Swedish version (MPI-S), The Self-Efficacy Scale, The Coping Strategies Questionnaire and The Pain Disability Index. Cluster analysis was conducted for the total sample MPI-S subscale scores. RESULTS: The adaptive copers cluster represented 42% of the sample, dysfunctional 34% of the sample, and interpersonally distressed 24% of the sample. The external validation of cluster solution showed that there were several significant differences between clusters in self-efficacy, disability and coping measures. There was also a significant interaction effect (clusterxtime) in disability (PDI). Patients in dysfunctional cluster reported a decreased disability over time. CONCLUSIONS: These results support the presence of different subgroups among patients with whiplash associated disorders. This classification can be seen as a complement to a classification based on medical condition. 相似文献