全文获取类型
收费全文 | 243017篇 |
免费 | 11569篇 |
国内免费 | 558篇 |
专业分类
耳鼻咽喉 | 3186篇 |
儿科学 | 7724篇 |
妇产科学 | 4949篇 |
基础医学 | 34601篇 |
口腔科学 | 5831篇 |
临床医学 | 19486篇 |
内科学 | 53455篇 |
皮肤病学 | 6508篇 |
神经病学 | 21582篇 |
特种医学 | 7622篇 |
外国民族医学 | 104篇 |
外科学 | 30058篇 |
综合类 | 1286篇 |
一般理论 | 67篇 |
预防医学 | 21951篇 |
眼科学 | 4718篇 |
药学 | 16883篇 |
4篇 | |
中国医学 | 802篇 |
肿瘤学 | 14327篇 |
出版年
2023年 | 1336篇 |
2022年 | 1077篇 |
2021年 | 3817篇 |
2020年 | 2289篇 |
2019年 | 4135篇 |
2018年 | 7684篇 |
2017年 | 5100篇 |
2016年 | 5088篇 |
2015年 | 5727篇 |
2014年 | 6120篇 |
2013年 | 9622篇 |
2012年 | 16451篇 |
2011年 | 16407篇 |
2010年 | 8299篇 |
2009年 | 6300篇 |
2008年 | 14015篇 |
2007年 | 15090篇 |
2006年 | 13860篇 |
2005年 | 13745篇 |
2004年 | 12899篇 |
2003年 | 11805篇 |
2002年 | 11109篇 |
2001年 | 6352篇 |
2000年 | 6394篇 |
1999年 | 5696篇 |
1998年 | 1085篇 |
1997年 | 897篇 |
1996年 | 827篇 |
1995年 | 744篇 |
1992年 | 3305篇 |
1991年 | 2966篇 |
1990年 | 2832篇 |
1989年 | 2594篇 |
1988年 | 2475篇 |
1987年 | 2271篇 |
1986年 | 2162篇 |
1985年 | 1939篇 |
1984年 | 1462篇 |
1983年 | 1233篇 |
1979年 | 1253篇 |
1978年 | 893篇 |
1977年 | 839篇 |
1975年 | 843篇 |
1974年 | 1021篇 |
1973年 | 1041篇 |
1972年 | 962篇 |
1971年 | 958篇 |
1970年 | 891篇 |
1969年 | 928篇 |
1968年 | 797篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Antonio López-Beltrán Alfonso S. Calañas Pilar Jimena Alberto L. Escudero Telma R. Campello Manuel Muñoz-Torres Fernando Escobar-Jiménez Rafael E. Carvia F. F. Nogales 《Virchows Archiv : an international journal of pathology》1997,431(2):149-151
Three further cases of mature benign cystic teratomas of the ovary associated with virilization are added to the three previously
reported in the literature. They were found in postmenopausal, obese, diabetic women aged 52, 61, and 67 years. The patients
presented with hirsutism and voice changes and clitoromegaly was present in one. Testosterone and androstenedione levels were
elevated but promptly regressed after removal of the tumours. Histologically, sheets of stromal luteinized cells were found
peripherally at the interface between the neoplasm and ovarian tissue. Luteinization of ovarian stroma induced by an unknown
factor related to diabetes mellitus is the origin of the virilization.
Received: 8 January 1997 / Accepted: 28 February 1997 相似文献
992.
Green fluorescent protein as a marker in Plasmodium berghei transformation 总被引:6,自引:0,他引:6 下载免费PDF全文
We present a new marker that confers both resistance to pyrimethamine and green fluorescent protein-based fluorescence on the malarial parasite Plasmodium berghei. A single copy of the cassette integrated into the genome is sufficient to direct fluorescence in parasites throughout the life cycle, in both its mosquito and vertebrate hosts. Erythrocyte stages of the parasite that express the marker can be sorted from control parasites by flow cytometry. Pyrimethamine pressure is not necessary for maintaining the cassette in transformed parasites during their sporogonic cycle in mosquitoes, including when it is borne by a plasmid. This tool should thus prove useful in molecular studies of P. berghei, both for generating parasite variants and monitoring their behavior. 相似文献
993.
Louis Journeau Marc-Antoine Pistorius Ulrique Michon-Pasturel Marc Lambert Francois-Xavier Lapébie Alessandra Bura-Riviere Philippe de Faucal Patrick Jego Quentin Didier Cécile Durant Geoffrey Urbanski Baptiste Hervier Claire Toquet Christian Agard Olivier Espitia 《Autoimmunity reviews》2019,18(5):476-483
994.
Florien van Heest Ilora Finlay Renée Otter Betty Meyboom-de Jong 《The British journal of general practice》2007,57(539):494-496
This study describes a novel type of support for GPs caring for patients dying at home: the establishment and evaluation of a telephone advisory service for GPs, run by GPs with a special interest in palliative care (GPwSIs) in the Netherlands 2000-2003. A growing number of GPs called for advice, 10% during out of hours. Prognosis of the patients was generally short (days to weeks in 70% of cases). Most advice sought by GPs concerned symptom management and on evaluation, 85% of the GPs followed the advice. 相似文献
995.
Eimeria tenella microneme protein EtMIC3: identification, localisation and role in host cell infection 总被引:1,自引:0,他引:1
Labbé M de Venevelles P Girard-Misguich F Bourdieu C Guillaume A Péry P 《Molecular and biochemical parasitology》2005,140(1):43-53
The gene coding for Eimeria tenella protein EtMIC3 was cloned by screening a sporozoite cDNA library with two independent monoclonal antibodies raised against the oocyst stage. The deduced sequence of EtMIC3 is 988 amino acids long. The protein presents seven repeats in tandem, with four highly conserved internal repeats and three more divergent external repeats. Each repeat is characterised by a tyrosine kinase phosphorylation site, WRCY, and a reminiscent motif of the thrombospondin1 (TSP1)-type I domain, CXXXCG. The protein EtMIC3 is localised at the apex of free parasite stages. It is not detected in the early intracellular parasite stage but is synthesised in mature schizonts. Secretion of the protein is induced when sporozoites are incubated in complete medium at 41 degrees C. Strangely enough, the two independent mAb that allow cloning of EtMIC3 interfere with parasitic growth in different ways. One is able to inhibit parasite invasion whereas the other inhibits development. Expression and localisation of the protein EtMIC3 are consistent with a protein involved in the invasion process as is expected for a microneme protein. 相似文献
996.
Summary We have characterized the ribosomal proteins from Spinacia chloroplasts using two-dimensional gel electrophoresis. The 30S and 50S subunits contain 23–25 and 36 ribosomal proteins, respectively. In contrast to prokaryotic ribosomes, chloroplast ribosomes contain at least one (and possibly two) phosphorylated ribosomal proteins. Isolated chloroplasts synthesize in the presence of (35S) labeled methionine and cysteine at least seven 30S and thirteen 50S ribosomal proteins which are assembled into (pre)ribosomes. This suggests that about one third of the chloroplast ribosomal proteins is encoded by the chloroplast DNA itself. The identity of several labeled proteins in the two-dimensional gel electrophoretic patterns which did not comigrate with stained chloroplast ribosomal proteins is discussed.Abbreviations CBB
Coomassie Brilliant Blue
- CHI
cycloheximide
- cp
chloroplast
- DTT
dithiotreitol
- EDTA
ethylene diamine tetraacetate
- EGTA
ethylene glycol-bis (-amino ethyl ether) N,N-tetraacetic acid
- kD
kilodalton
- LHCP
light harvesting chlorophyll a/b protein
- PMSF
phenyl methyl sulfonyl fluoride
- RuBPCase
ribulose-1,5-bisphosphate carboxylase
- SDS
sodiumdodecylsulphate 相似文献
997.
The authors found tardive dyskinesia (TD) in 23.5% of 200 hospitalized schizophrenic patients, most of whom had received neuroleptic treatment for at least two years. The frequency and severity of TD increased with age, and the more advanced the age at which the patient started taking neuroleptics, the more likely it was that TD would develop. Severe TD was more common in men than in women. Prolonged treatment with neuroleptics or the use of antiparkinsonism drugs increased the risk of TD. 相似文献
998.
Hera Der-Sarkissian Catherine Bonaïti-Pellié Marie-Louise Briard-Guillemot Jean-Michel Zucker 《Cancer Genetics and Cytogenetics》1982,7(1):73-77
Spontaneous and mitomycin C(MMC)-induced sisyer chromatid exchanges were studied in 11 patients with retinoblastoma and 7 normal controls. Spontaneous rates were similar in patients and in controls. The MMC-induced rate was found to be significantly higher in bilaterally affected patients than in controls. It is suggested that this increase may be due to a DNA repair deficiency. However, it is not possible to clarify wether this abnormality is associated with the retinoblastoma gene or with another factor acting on the degree of expressivity of the disease in gene carriers. 相似文献
999.
The energetics of middle-distance running 总被引:3,自引:0,他引:3
J. R. Lacour S. Padilla-Magunacelaya J. C. Barthélémy D. Dormois 《European journal of applied physiology》1990,60(1):38-43
Summary In order to assess the relative contribution of aerobic processes to running velocity (v), 27 male athletes were selected on the basis of their middle-distance performances over 800, 1500, 3000 or 5000 m, during the 1987 track season. To be selected for study, the average running velocity
corresponding to their performances had to be superior to 90% of the best French
of the season. Maximum O2 consumption
and energy cost of running (C) had been measured within the 2 months preceding the track season, which, together with oxygen consumption at rest
allowed us to calculate the maximalv that could be sustained under aerobic conditions:
. The treadmill runningv corresponding to a blood lactate of 4 mmol·–1 (v
la4), was also calculated. In the whole group, C was significantly related to height (r=–0.43;P<0.03). Neither C nor
(with, in this case, the exception of the 3000 m athletes) were correlated to
. On the other hand,v
a max was significantly correlated to
over distances longer than 800 m. These
were also correlated tov
la4. Howeverv
la4 occurred at 87.5% SD 3.3% ofv
a max, this relationship was interpreted as being an expression of the correlation betweenv
a max and
. Calculation ofv
a max provided a useful means of analysing the performances. At the level of achievement studied,
sustained over 3000 m corresponded tov
a max. The shape of the relationship ofv/v
a max as a function of the duration of the event raised the question of a possible change in C as a function of v during middle-distance running competitions. 相似文献
1000.
Jennifer A. Ruskey Lior Greenbaum Léanne Roncière Armaghan Alam Dan Spiegelman Christopher Liong Oren A. Levy Cheryl Waters Stanley Fahn Karen S. Marder Wendy Chung Gilad Yahalom Simon Israeli-Korn Vered Livneh Tsvia Fay-Karmon Roy N. Alcalay Sharon Hassin-Baer Ziv Gan-Or 《European journal of medical genetics》2019,62(1):65-69