全文获取类型
收费全文 | 11715篇 |
免费 | 690篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 261篇 |
妇产科学 | 232篇 |
基础医学 | 1566篇 |
口腔科学 | 476篇 |
临床医学 | 913篇 |
内科学 | 3156篇 |
皮肤病学 | 269篇 |
神经病学 | 1438篇 |
特种医学 | 357篇 |
外科学 | 1295篇 |
综合类 | 31篇 |
一般理论 | 2篇 |
预防医学 | 500篇 |
眼科学 | 139篇 |
药学 | 770篇 |
中国医学 | 37篇 |
肿瘤学 | 960篇 |
出版年
2023年 | 71篇 |
2022年 | 169篇 |
2021年 | 316篇 |
2020年 | 174篇 |
2019年 | 254篇 |
2018年 | 308篇 |
2017年 | 233篇 |
2016年 | 255篇 |
2015年 | 302篇 |
2014年 | 421篇 |
2013年 | 532篇 |
2012年 | 862篇 |
2011年 | 882篇 |
2010年 | 459篇 |
2009年 | 418篇 |
2008年 | 750篇 |
2007年 | 760篇 |
2006年 | 691篇 |
2005年 | 739篇 |
2004年 | 639篇 |
2003年 | 599篇 |
2002年 | 550篇 |
2001年 | 191篇 |
2000年 | 175篇 |
1999年 | 172篇 |
1998年 | 143篇 |
1997年 | 95篇 |
1996年 | 97篇 |
1995年 | 94篇 |
1994年 | 68篇 |
1993年 | 58篇 |
1992年 | 95篇 |
1991年 | 81篇 |
1990年 | 88篇 |
1989年 | 87篇 |
1988年 | 63篇 |
1987年 | 64篇 |
1986年 | 58篇 |
1985年 | 43篇 |
1984年 | 45篇 |
1983年 | 45篇 |
1982年 | 31篇 |
1980年 | 23篇 |
1979年 | 33篇 |
1978年 | 19篇 |
1976年 | 19篇 |
1975年 | 20篇 |
1974年 | 17篇 |
1972年 | 18篇 |
1968年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
102.
Parra ER Canzian M Saber AM Coêlho RS Rodrigues FG Kairalla RA de Carvalho CR Capelozzi VL 《Pathology, research and practice》2004,200(10):701-705
Previous reports indicate that enlarged hilar and mediastinal lymph nodes caused by sarcoid-like reactions may develop after curative resection of cancer, and their presence does not necessarily denote neoplastic recurrence. Reports further suggest that coexisting pulmonary infiltrates in this setting may be related to sarcoidosis. In this study, we describe two patients who had resected lung and gastric cancer and who later developed pulmonary interstitial infiltrate, concurrent with progressive mediastinal lymphadenopathy initially thought to be caused by intrathoracic dissemination of their cancer. These changes were shown by open lung biopsy to be a benign, granulomatous reaction interpreted as sarcoidosis. Thus, it is important to recognize this clinical pattern when pulmonary infiltrates develop after complete treatment of cancer in an otherwise relapse-free patient and to encourage lung or lymph node biopsy in these particular settings in order to confirm a sarcoid-like reaction, thereby avoiding unnecessary chemotherapy for presumed tumor recurrence. 相似文献
103.
Gil LH Alves FP Zieler H Salcedo JM Durlacher RR Cunha RP Tada MS Camargo LM Camargo EP Pereira-da-Silva LH 《Journal of medical entomology》2003,40(5):636-641
Studies on seasonal anopheline fauna variation were performed in two distinct settlements in the State of Rond?nia, Brazil: one at the Madeira River banks (Portuchuelo) with stable native Amazonian population; the other at an inland lumber-extracting farm (Urupá) in dry land, in which adults are mostly migrants. During a 6-yr period (1994-2000), 8,638 adult anophelines were collected: 2,684 in Urupá and 5,954 in Portuchuelo. Anopheles darlingi represented >95% of total mosquitoes caught. Dissection of 4,424 A. darlingi females yielded a very low sporozoite infection index below 0.1%. Oocysts were found in both localities in approximately 0.1% of dissected mosquitoes. Determination of the hour biting rates disclosed seasonal variations in both localities. However, in Portuchuelo, mosquito density peaked at the acme of the rainy season, whereas at Urupá it peaked in the dry season. The increase in mosquito density and incidence of malaria cases were coincident. The high mosquito densities observed in the riverine settlement of Portochuelo sector B, which permits evaluation in > 10,000 mosquitoes' bites/person/year, could explain, in spite of the low mosquito's infection index, the previously described development of natural immunity in the local population that is not observed in the dry land agroindustrial settlement of Urupá. 相似文献
104.
105.
Trisomy 8 in myelodysplasia and acute leukemia is constitutional in 15-20% of cases. 总被引:2,自引:0,他引:2
Emanuela Maserati Fiorenza Aprili Fabrizio Vinante Franco Locatelli Giovanni Amendola Adriana Zatterale Giuseppe Milone Antonella Minelli Franca Bernardi Francesco Lo Curto Francesco Pasquali 《Genes, chromosomes & cancer》2002,33(1):93-97
The trisomy 8 found in malignancies may derive from a constitutional trisomy 8 mosaicism (CT8M), and in these cases the trisomy itself may be regarded as the first mutation in a multistep carcinogenetic process. To assess the frequency of CT8M in hematological dysplastic and neoplastic disorders with trisomy 8, an informative sample of 14 patients was collected. The data ascertained included chromosome analyses of fibroblast cultures and of PHA-stimulated blood cultures in patients with normal blood differential count, as well as possible CT8M clinical signs. One patient showed trisomy 8 in all cell types analyzed and undoubtedly has a CT8M; a second patient consistently showed trisomy 8 in PHA-stimulated blood cultures when no immature myeloid cells were present in blood and should be considered as having CT8M; a third patient, with Philadelphia-positive chronic myelocytic leukemia, was more difficult to interpret, but the possibility that she had CT8M is likely. A few clinical signs of CT8M were also present in these three patients. Our data indicate that the frequency of CT8M in hematological dysplastic and neoplastic disorders with trisomy 8 is approximately 15-20%. 相似文献
106.
Merati G Negrini S Sarchi P Mauro F Veicsteinas A 《European journal of applied physiology》2001,85(1-2):41-48
The use of a school backpack is one of the possible causes of back pain in children. Oxygen consumption (
), pulmonary ventilation, and heart rate (f
c) were measured in 35 pre-pubertal subjects [17 girls and 18 boys, mean (SD) age 11.3 (0.6) years]. They took part in a four-step
experiment: (1) standing for 5 min, (2) walking at 3 km·h–1 for 7 min, (3) walking at 3 km·h–1 for 7 min carrying a school backpack weighing 8 kg, and (4) walking at 7 km·h–1 for 5 min with no load. The occurrence of back pain in the last 2–3 years and during the last 15 days was assessed for the
subjects by means of a questionnaire. Mean (SD) standing
was 215 (45) ml.min–1 during walking at 3 km·h–1, 503 (101) ml.min–1 during walking without a load, and increased to 541 (98) ml.min–1 during walking with a load (P<0.01). Carrying a backpack increased f
c only minimally. The energy cost of walking at 3 km.h–1 without the backpack was 10.0 (2.0) ml O2
.m–1, and with the backpack was 10.8 (1.9) ml O2
.m–1 (P<0.01). The net energy cost of locomotion was 0.129 (0.032) ml.kg body mass–1.m–1 for the unloaded condition and slightly lower, at 0.123 (0.025) ml.kg body mass–1.m–1 during loaded walking (P<0.05). Ventilation did not change significantly between unloaded and loaded conditions. When the data were assessed according
to the occurrence of back pain, the f
c/
slope was significantly lower in children without back pain, even though the net energy cost of locomotion was similar. Overall,
these data suggest that the cardiovascular effortrequired for locomotion while carrying a backpack is minimal. However, fatigability
and back pain are more likely to take place in less physical performing subjects. Thus, the occurrence of back pain in schoolchildren
during locomotion while carrying a backpack may improve with an improvement in their level of fitness.
Electronic Publication 相似文献
107.
108.
Abstract: Although many studies have established an association between insulin-dependent diabetes mellitus (IDDM) and the class II region of the human major histocompatibility complex (MHC), it has been difficult to assign susceptibility to a single locus. Recently, two antigen-processing genes, TAP1 and TAP2 , have been identified within the region. Previous studies have reached conflicting conclusions as to the role of these genes in IDDM; it is uncertain whether an increased frequency of the allele TAP2A and a concomitant decrease in TAP2B are independent disease associations or secondary to linkage disequilibrium (LD) between TAP2A and HLA-DR3 . To further investigate this question, we have characterized TAP1 and TAP2 alleles in 129 IDDM patients from Sardinia, a population with limited genetic heterogeneity and a high disease incidence. When compared to 90 random controls, the only significant difference was a decrease in the minor allele TAP2C in patients. However, when HLA-DR and - DQ matched controls were compared, this difference disappeared. Further analysis suggested that TAP2C was in LD with HLA-DRB1*1401 and subtypes of HLA-DRB1*11 , alleles which were not observed in the IDDM population. LD was also observed between other TAP and HLA-DR alleles, in particular between TAP2A and HLA-DR3 in both patients and controls. Our data supports the conclusion that there is no primary association between TAP2 alleles and IDDM, and that previously reported associations may be due to LD with other class II loci. 相似文献
109.
Erika L. D. Mitchell Gavin R. M. White Mauro F. Santibanez-Koref Jenny M. Varley Jim Heighway 《Chromosome research》1995,3(4):261-262
The gene loci CDK4, GLI, CHOP and MDM2 have been mapped to the q13–q15 region of chromosome 12. Using fluorescencein situ hybridization onto simultaneously DAPI-banded metaphase chromosomes and interphase nuclei, we have more precisely mapped and ordered these loci, together with a number of Genethon microsatellite markers. GLI and CHOP localize to 12q13.3–14.1, CDK4 to 12q14 and MDM2 to 12q14.3–q15, and the gene order is cen-GLI/CHOP-CDK4-MDM2. The Genethon microsatellites D12S80 and D12S83 flank MDM2. 相似文献
110.
Apoptosis or programmed cell death (PCD) is an active process of cellular self-destruction, essential for embryonic development and maintenance of homeostasis of multicellular organisms. Programmed cell death induction can serve as a defence mechanism of the host against intracellular microbes. Virus infections trigger host cell apoptosis, which can either limit virus production or contribute directly to viral pathogenesis.Several independent laboratories have identified "tissue" transglutaminase (tTG) as a potentially important player of the cell death program(s). This gene is specifically expressed in cells dying during mammalian development as well as in those undergoing apoptosis in various patho-physiological and experimental settings [Eur. J. Cell Biol. 56 (1991) 170; Piacentini, M., Davies, P.J.A., Fesus, L., 1994. Tissue transglutaminase in cells undergoing apoptosis. In: Tomei, L.D., Cope, F.O. (Eds.), Apoptosis II: The molecular basis of apoptosis in disease. Cold Spring Harbor Lab. Press, pp. 143-165.]. This chapter reviews recent studies concerning the expression and the possible role of "tissue" transglutaminase (tTG) in apoptotic cells; particular emphasis is given to its expression in the cell death pathways associated with HIV infection in the immune system.We propose here that the induction of the tTG gene in cells of the immune system, as well as the detection of the isodipeptide epsilon(gamma-glutamyl)lysine in plasma, are useful markers of apoptosis and might make it possible to monitor disease progression in HIV-infected individuals. 相似文献