全文获取类型
收费全文 | 2973篇 |
免费 | 381篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 94篇 |
妇产科学 | 66篇 |
基础医学 | 517篇 |
口腔科学 | 68篇 |
临床医学 | 367篇 |
内科学 | 526篇 |
皮肤病学 | 26篇 |
神经病学 | 364篇 |
特种医学 | 93篇 |
外科学 | 352篇 |
综合类 | 64篇 |
一般理论 | 3篇 |
预防医学 | 277篇 |
眼科学 | 82篇 |
药学 | 262篇 |
中国医学 | 1篇 |
肿瘤学 | 159篇 |
出版年
2021年 | 41篇 |
2020年 | 29篇 |
2019年 | 48篇 |
2018年 | 48篇 |
2017年 | 29篇 |
2016年 | 41篇 |
2015年 | 40篇 |
2014年 | 64篇 |
2013年 | 106篇 |
2012年 | 153篇 |
2011年 | 160篇 |
2010年 | 73篇 |
2009年 | 66篇 |
2008年 | 122篇 |
2007年 | 141篇 |
2006年 | 128篇 |
2005年 | 104篇 |
2004年 | 110篇 |
2003年 | 84篇 |
2002年 | 109篇 |
2001年 | 98篇 |
2000年 | 88篇 |
1999年 | 92篇 |
1998年 | 65篇 |
1997年 | 44篇 |
1996年 | 22篇 |
1995年 | 49篇 |
1994年 | 27篇 |
1993年 | 50篇 |
1992年 | 66篇 |
1991年 | 65篇 |
1990年 | 59篇 |
1989年 | 69篇 |
1988年 | 71篇 |
1987年 | 72篇 |
1986年 | 62篇 |
1985年 | 66篇 |
1984年 | 35篇 |
1983年 | 47篇 |
1981年 | 31篇 |
1980年 | 32篇 |
1979年 | 56篇 |
1978年 | 31篇 |
1977年 | 27篇 |
1976年 | 26篇 |
1975年 | 28篇 |
1974年 | 31篇 |
1973年 | 35篇 |
1972年 | 32篇 |
1970年 | 21篇 |
排序方式: 共有3365条查询结果,搜索用时 31 毫秒
31.
S. D. Stocker B. C. Steinbacher Jr. C. D. Balaban B. J. Yates 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,116(2):270-282
A region of the caudal ventrolateral medullary reticular formation (CVLM) participates in baroreceptor, vestibulosympathetic,
and somatosympathetic reflexes; the adjacent retroambigual area is involved in generating respiratory-related activity and
is essential for control of the upper airway during vocalization. However, little is known about the connections of the CVLM
in the cat. In order to determine the locations of terminations of CVLM neurons, the anterograde tracers Phaseolus vulgaris leucoagglutinin and tetramethylrhodamine dextran amine were injected into this region. These injections produced a dense concentration
of labeled axons throughout the lateral medullary reticular formation (lateral tegmental field), including the retrofacial
nucleus and nucleus ambiguus, regions of the rostral ventrolateral medulla, the lateral and ventrolateral aspects of the hypoglossal
nucleus, nucleus intercalatus, and the facial nucleus. A smaller number of labeled axons were located in the medial, lateral,
and commissural subnuclei of nucleus tractus solitarius, the A5 region of the pontine reticular formation, the ventral and
medial portions of the spinal and motor trigeminal nuclei, locus coeruleus, and the parabrachial nucleus. We confirmed the
projection from the CVLM to both the rostral ventrolateral medulla and lateral tegmental field using retrograde tracing. Injections
of biotinylated dextran amine or Fluorogold into these regions resulted in retrogradely labeled cell bodies in the CVLM. However,
the neurons projecting to the lateral tegmental field were located mainly dorsal to those projecting to the rostral ventrolateral
medulla, suggesting that these neurons form two groups, possibly with different inputs. Injections of retrograde tracers into
the lateral tegmental field and rostral ventrolateral medulla also produced labeled cell bodies in other regions, including
the medial and inferior vestibular nuclei and nucleus solitarius. These data are consistent with the view that the CVLM of
the cat is a multifunctional area that regulates blood pressure, produces vocalization, affects the shape of the oral cavity,
and elicits contraction of particular facial muscles.
Received: 18 February 1997 / Accepted: 27 March 1997 相似文献
32.
Identification of the multiple endocrine neoplasia type 1 (MEN1) gene. The European Consortium on MEN1 总被引:10,自引:0,他引:10
Lemmens I; Van de Ven WJ; Kas K; Zhang CX; Giraud S; Wautot V; Buisson N; De Witte K; Salandre J; Lenoir G; Pugeat M; Calender A; Parente F; Quincey D; Gaudray P; De Wit MJ; Lips CJ; Hoppener JW; Khodaei S; Grant AL; Weber G; Kytola S; Teh BT; Farnebo F; Thakker RV 《Human molecular genetics》1997,6(7):1177-1183
33.
Michael S. Yates C. Robin Hiley 《Pflügers Archiv : European journal of physiology》1979,379(2):219-222
The distribution of cardiac output was determined by 15 m radioactive microspheres in all the major organs of spontaneous, DOCA/NaCl and one kidney Goldblatt hypertensive rats and compared to normotensive Wistar rats. Although there were alterations in cardiac output distribution which were characteristic of each model of hypertension significant changes were common to all three were an increased distribution to skeletal muscle with decreases to the lungs, spleen and hepatosplanchnic tissues. The results suggest that alterations in peripheral resistance induced by hypertension are of unequal importance in the different vascular beds with certain vascular resistance changes occurring irrespective of the origin of the hypertension.Abbreviations used in this paper SHR
spontaneously hypertensive rats
- DOCA
deoxycorticosterone acetate
Supported by I.C.I. Pharmaceutical Ldt and the Mersey Regional Health Authority (Research Schemes No. 338). 相似文献
34.
M. Fauville-Dufaux B. Vanfleteren L. De Wit J. P. Vincke J. P. Van Vooren M. D. Yates E. Serruys J. Content 《European journal of clinical microbiology & infectious diseases》1992,11(9):797-803
A polymerase chain reaction (PCR) assay was developed for detection of mycobacteria using amplification of a 162 bp region of the genes coding for the mycobacterial antigen 85 complex. Strains belonging to theMycobacterium tuberculosis complex were further differentiated from non-tuberculous mycobacteria by hybridization of the PCR derived Southern blot with an internal oligonucleotide probe and washing under stringent conditions. The method allowed rapid and sensitive detection of mycobacterial DNA in uncultured clinical samples. PCR results obtained forMycobacterium tuberculosis in 206 specimens from 180 untreated patients gave a sensitivity of 93.9% and a specificity of 94.3% compared with the culture. PCR detected DNA fromMycobacterium tuberculosis in seven samples from patients with clinically evident tuberculosis in whom culture was negative. The results suggest that this PCR assay could be used for early and specific diagnosis of tuberculosis. 相似文献
35.
Glial cell line-derived neurotrophic factor (GDNF) has many functions including regulation of kidney morphogenesis and of neuron growth and survival in the enteric, sensory and central nervous systems. Reports of GDNF being used against Parkinson's disease in human patients have sparked intense clinical interest in GDNF signalling. We recently showed that GDNF signalling requires cell surface heparan sulphate glycosaminoglycans (Barnett et al., 2002, J. Cell Sci. 115, 4495-4503). Here we use exogenous modified heparins to determine those structural features required to inhibit GDNF signalling in ex vivo assays. 2-O-sulphate groups were found to impart high activity but were not absolute requirements for the inhibition of GDNF signalling. These findings may explain the similarities between the phenotypes of transgenic mice lacking GDNF and those lacking heparan sulphate 2-sulphotransferase, the enzyme responsible for achieving 2-O-sulphation of uronic acids in vivo. 相似文献
36.
Fleming R Rehka P Deshpande N Jamieson ME Yates RW Lyall H 《Human reproduction (Oxford, England)》2000,15(7):1440-1445
There has been much debate about the role of luteinizing hormone (LH) during follicle stimulating hormone (FSH)-treated ovarian stimulation for assisted reproduction, where the endogenous LH is suppressed using a gonadotrophin-releasing hormone analogue. The requirement for LH in oestradiol biosynthesis is established, but other effects of 'insufficiency' are less clear, and little attention has been paid to the specific origin of the FSH used. The aim of this study was to examine the roles of profoundly suppressed circulating LH concentrations in cycles of ovarian stimulation for IVF, which were affected in two large separate cohorts of patients undergoing assisted reproduction. They were stimulated by either purified urinary FSH (MHP) or recombinant human FSH (rFSH). Within each dataset, outcomes were examined with respect to the circulating concentrations of LH in the mid-follicular phase, as plasma samples were stored prospectively, and assayed retrospectively. Patients with profoundly suppressed LH showed much reduced oestradiol concentrations at mid-follicular phase and at human chorionic gonadotrophin administration in cycles treated with either MHP or rFSH. However, gross ovarian response, as became evident by FSH dose demands, duration of stimulation, and also oocyte and embryo yields and embryo cryopreservation were influenced only in cycles treated with MHP. Furthermore, no effect upon pregnancy survival was observed. Thus, it is concluded that there is a demand for additional exogenous LH treatment only in cycles treated with purified urinary FSH where the LH is profoundly suppressed. 相似文献
37.
Vance J. Yates Abla M. El Mishad Kenneth J. McCormick John J. Trentin 《Infection and immunity》1973,7(6):973-980
An 18- to 20-nm virus particle was isolated from the Olson strain of quail bronchitis, an avian adenovirus. On density gradient separation the small virions were primarily found at densities of 1.39 and 1.42 g/cm(3). The majority of the infectious particles were at the heavier density. The virus had a hexagonal outline and contained single-stranded deoxyribonucleic acid. It was resistant to heating at 56 C for more than an hour and was not inactivated by treatment with chloroform or low pH. Purified virus did not agglutinate erythrocytes of various avian and mammalian species. Replication of the small particles occurred either in chicken embryos or in cultures of embryo kidney cells coinfected with an adenovirus helper. Antigenically the virus was distinct from the adeno-associated viruses types 1, 2, 3, and 4. The virus is the avian equivalent of the adeno-associated viruses of primates and lower animals. 相似文献
38.
39.
Chung C.C.; Fleming R.; Jamieson M.E.; Yates R.W.S.; Coutts J.R.T. 《Human reproduction (Oxford, England)》1995,10(12):3139-3141
The aim of this prospective randomized controlled study wasto determine the possible role of ovulation induction with intrauterineinsemination (IUI) in the treatment of unexplained infertility.A total of 100 patients were randomized to receive ovulationinduction with or without IUI. All patients were treated withlong-course gonadotrophinreleasing hormone analogue (GnRHa),starting in the luteal phase, and exogenous follicle stimulatinghormone (FSH) to induce follicular growth. Ovulation was inducedusing human chorionic gonadotrophin and timed intercourse (TI)was advised 2448 h later or IUI was effected 3648h later. Both the cycle fecundities (21.8 and 8.5%) and thecumulative ongoing pregnancy rates after three cycles (42 and20%) were significantly higher (P < 0.03) in the IUI groupthan in the TI group respectively. This is a clear indicationthat ovulation induction with IUI is an effective treatmentmethod for unexplained infertility, but ovulation inductionwith TI has a negligible impact in this large group of patients. 相似文献
40.
Tagoe CN Ayettey AS Dennis E Yates RD 《Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia》1995,100(Z1):273-286
Cells of the impulse-generating and conducting tissues of the insect-eating bat Pipistrellus pipistrellus were studied and evaluated using ultrastructural morphometry. Sinoatrial node cells are smaller than working atrial cells and measure about 6.5 microm in diameter. Their mitochondira and myofibril content constitute 23% and 19% of cytoplasmic volume, respectively. Corresponding values for working atrial cells are 23% and 52%. Atrioventricular node cells are 4.2 microm in diameter and contain abundant glycogen in the cytoplasm. The fractional volume of mitochondria in about 24% while that of myofibrils is 7%. Cells of the bundle of His are larger (6-8 microm diameter) and contain more cellular organelles than do nodal cells. Their mitochondria and myofibril contents are 25% and 25%, respectively. Cells in the proximal part of the right bundle branch are slender with diameters averaging 3.4 microm. Mitochondrial content is 23% while myofibrils occupy 20% of the cytoplasmic volume of these cells. Distally located bundle branch cells measure 7-10 microm in diameter with mitochondria and myofibril volumes of 30% and 33%. Subendocardial cells in the ventricular free wall are large reaching 28 microm in diameter (cf. 14-18 microm in working ventricular cells) and have mitochondira and myofibril volume fractions of 32% and 29%, respectively (35% & 40% for working ventricular cells). 相似文献