全文获取类型
收费全文 | 1046578篇 |
免费 | 77125篇 |
国内免费 | 10400篇 |
专业分类
耳鼻咽喉 | 13928篇 |
儿科学 | 25433篇 |
妇产科学 | 24367篇 |
基础医学 | 146358篇 |
口腔科学 | 30135篇 |
临床医学 | 96105篇 |
内科学 | 200245篇 |
皮肤病学 | 20390篇 |
神经病学 | 78241篇 |
特种医学 | 41021篇 |
外国民族医学 | 157篇 |
外科学 | 163692篇 |
综合类 | 38641篇 |
现状与发展 | 41篇 |
一般理论 | 240篇 |
预防医学 | 69536篇 |
眼科学 | 24616篇 |
药学 | 84537篇 |
98篇 | |
中国医学 | 9217篇 |
肿瘤学 | 67105篇 |
出版年
2021年 | 11924篇 |
2020年 | 8365篇 |
2019年 | 9901篇 |
2018年 | 13066篇 |
2017年 | 10691篇 |
2016年 | 11256篇 |
2015年 | 14210篇 |
2014年 | 18546篇 |
2013年 | 23265篇 |
2012年 | 32442篇 |
2011年 | 34312篇 |
2010年 | 20656篇 |
2009年 | 18868篇 |
2008年 | 30532篇 |
2007年 | 31541篇 |
2006年 | 32164篇 |
2005年 | 31205篇 |
2004年 | 28273篇 |
2003年 | 27021篇 |
2002年 | 26089篇 |
2001年 | 57209篇 |
2000年 | 59202篇 |
1999年 | 49815篇 |
1998年 | 12677篇 |
1997年 | 11455篇 |
1996年 | 11118篇 |
1995年 | 10381篇 |
1994年 | 9532篇 |
1993年 | 8375篇 |
1992年 | 36425篇 |
1991年 | 34656篇 |
1990年 | 33360篇 |
1989年 | 32462篇 |
1988年 | 29494篇 |
1987年 | 28682篇 |
1986年 | 26661篇 |
1985年 | 25417篇 |
1984年 | 17956篇 |
1983年 | 15244篇 |
1979年 | 15833篇 |
1978年 | 10598篇 |
1977年 | 9052篇 |
1976年 | 7871篇 |
1975年 | 8628篇 |
1974年 | 10467篇 |
1973年 | 9858篇 |
1972年 | 9357篇 |
1971年 | 8852篇 |
1970年 | 8426篇 |
1969年 | 7923篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
R T Pham M Sung C R Dawson J Schachter 《Investigative ophthalmology & visual science》1990,31(7):1367-1373
The development and testing of candidate vaccines for trachoma are constrained because only humans and nonhuman primates are susceptible to conjunctival infection with Chlamydia trachomatis. Guinea pig inclusion conjunctivitis (GPIC), an analogous disease of guinea pigs, provides a useful, less expensive model to study ocular chlamydial infections. GPIC is caused by a Chlamydia psittaci strain whose external constituents are very similar to those of C. trachomatis. To develop a better model for studying GPIC immunity, conjunctival pockets were established under the abdominal skin of guinea pigs by subcutaneous implantation. Up to six implants could be produced in each animal. The success rate of implantation was 79.0% (n = 148). These pockets were then infected with GPIC. The organism was recovered from the autografts indicating local replication, and tests for serum antibody by microimmunofluorescence showed production of GPIC-specific antibody of IgG and IgM classes after infection. There was minimal antibody response after moderate inoculating doses to the implants, and the titers increased more slowly than after eye infection with GPIC; with higher concentration of the inoculum, however, the antibody response increased to the same levels as with the ocular challenge but more slowly. Inoculation of pockets with GPIC also produced acute inflammatory changes in infected autografts (n = 101). Histologic examination of infected grafts showed chlamydial inclusions in epithelial cells and significant infiltration with lymphocytes and polymorphonuclear cells. Subcutaneous autografts may provide a useful model for chronologic studies of chlamydial infection. The delayed immunologic response, however, suggests that these pockets of implanted epithelium do not have full access to the immune system. 相似文献
992.
993.
James T. Sykes 《Australasian journal on ageing》1998,17(Z1):93-95
Abstract. During the 1997 Congress on Gerontology the issue of advocacy was prominently raised in numerous sessions. The delegates affirmed the Declaration of Adelaide, an important statement which called attention to the policy implications of scientific findings. The Declaration set research, practice and education agendas and urged increased resources for gerontological research and programs affecting the well-being of older persons and their families. The wisdom of “linking what we know and can do with what we hope for and desire,” as the theologian Jurgen Moltman has written, requires a systematic effort on the part of gerontologists to influence public policy, standards and professional practice. In short, gerontologists must become advocates. To be effective advocates they must raise awareness of critical issues, form coalitions with those who share the goal of a better world, and exchange information and best practices if the elders of society today - and those who will be the elders of tomorrow - are to benefit from science translated into sound policies and effective practices. Gerontologists must take their scientific findings - and questions - to the forums where policies are discussed and standards and practices developed. 相似文献
994.
Minor Psychiatric Morbidity, Its Prevalence and Outcome in a Cohort of Civil Servants A Seven-year Follow-up Study 总被引:1,自引:0,他引:1
Jenkins R.; Harvey S.; Butler T.; Lloyd Thomas R. 《Occupational medicine (Oxford, England)》1996,46(3):209-215
During the years 1979–1986, a cohort of direct entrantexecutive officers in the Civil Service were followed up toexamine the prevalence and outcome of minor psychiatric morbidityin an occupational setting. All studies using epidemiologicalstandardized research methods agree, that prevalence rates arehigh in occupational settings. As in primary care settings,half of the illness episodes followed a chronic course, whichemphasizes the need for early detection and prompt managementof these conditions, and for evaluative studies of interventionstrategies. 相似文献
995.
G. Bradley Schaefer James N. Thompson John B. Bodensteiner James M. McConnell William J. Kimberling Charles T. Gay William D. Dutton David C. Hutchings Stanton B. Gray 《Annals of neurology》1996,39(3):382-385
There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions without autistic behavior. This suggests that it is not a specific neuroanatomical marker for autism, nor is cerebellar dys- genesis likely to be solely responsible for clinical autistic behaviors. 相似文献
996.
Harold T. Kyriazi George E. Carvell Joshua C. Brumberg Daniel J. Simons 《Brain research》1996,712(2):325
Extracellular single-unit recordings were made in somatosensory cortical barrels of fentanyl-sedated rats. Whiskers were deflected singly or in paired combinations. lontophoretically-applied (−)-baclofen disproportionately reduced weak responses, and phaclofen disproportionately increased them, resulting in more tightly focused or more broadly focused receptive fields, respectively. Both drugs had only minor effects on surround inhibition. In light of previous findings, we conclude that GABAA and GABAB mechanisms both act to enhance spatial contrast, but that the former plays a much greater role in enhancing temporal resolution. 相似文献
997.
Proliferative activity of mast cells in allergic nasal mucosa 总被引:4,自引:1,他引:3
The proliferative activity of mast cells in the nasal mucosae of allergic (n= 14) and non-allergic (n= 18) rhinopathic patients was studied by a sequential double immuno-histochemistry using anti-proliferating cell nuclear antigen (PCNA) and anti-tryptase antibodies. Two hundred to 300 tryptase-positive cells (mast cells) were studied in each allergic nasal epithelium. In case of non-allergic nasal mucosa, only a few mast cells existed in the epithelial layer. The total number of mast cells which we could detect in all patients was 168 cells. One of these cells contained PCNA. Three hundred to 500 mast cells were studied in each subepithelial layer and deep layer of lamina propria of both diseases. PCNA-positive mast cells were observed in the nasal epithelia of 10 allergic patients. In the subepithelial layer, PCNA-positive mast cells were observed eight allergic patients and four non-allergic patients, respectively, In the deep lamina propria, PCNA-positive mast cells were observed in a few patients with both diseases. The percentage of PCNA-positive mast cells of all mast cells each area ranged from 0 to 1.7%. The incidence of PCNA-positive mast cells was statistically higher in the allergic epithelium and subepithelial layer than in the deep layer of lamina propria. Moreover, that of PCNA-positive mast cells in the subepithelial layer was higher in allergic than in non-allergic nasal mucosa. Our results suggest that mast cell proliferation may contribute to the number of mast cells in the nasal epithelium and subepithelial layer of allergic patients. 相似文献
998.
M. Vrethem B. Lindvall S. Kihlstrand E. Bckman T. Brismar P. Fredman K.G. Henriksson 《European journal of neurology》1996,3(2):156-159
We report improvement in muscle strength in a patient with multifocal motor neuropathy (MMN) when given high-dose intravenous immunoglobin (i.v.-Ig) treatment. The patient had asymmetrical limb weakness, atrophy and absent or weak reflexes, but no sensory disturbances. Neurography showed multiple conduction blocks in peripheral motor nerves but no sensory nerve abnormalities. Serum and anti-GM1 antibodies were not found, however, the patient had serum antibodies against the glycolipid LK1, an epitope found both in glycolipid and also in some glycoproteins in peripheral nerve myelin. Muscle strength improved 5 days after i.v.-Ig therapy, and lasted about 10 weeks. Repeated courses of treatment resulted in similar improvement. This is, to our knowledge, the first patient reported with MMN found to have antibodies against the glycolipid LK1. 相似文献
999.
H. Inaba M.D. J. Sato H. Uchida M. Sakurada T. Ohwada T. Mizuguchi 《Acta anaesthesiologica Scandinavica》1988,32(5):374-378
Fluctuating PEEP (F-PEEP) is a newly developed PEEP in which end-expiratory pressure (EEP) is periodically changed within a certain range. In a dog model with unilateral lung injury induced by the introduction of hydrochloric acid, F-PEEP in which the EEP was periodically changed from 0.5 to 1.5 kPa at periods of 6 min, and conventional PEEP (C-PEEP) with an optimized EEP of 1.0 kPa, were each applied for 30 min. F-PEEP produced a significantly greater improvement of PaO2 and intrapulmonary shunt (QS/QT) than C-PEEP, and at the low EEP phase, the greatest improvement accompanied by an increased dynamic compliance and a large cardiac output was obtained. These results suggest that F-PEEP provides a useful mode of artificial ventilation for the treatment of unilateral lung injury. 相似文献
1000.
M Bijanzadeh M Mahmoudian P Salehian T Khazainia L Eshghi A Khosravy 《Indian journal of physiology and pharmacology》1990,34(3):157-161
Tablets of either microsized or ultramicrosized griseofulvin (2 x 125 mg), were administered to 6 healthy volunteers of either sex just before a breakfast containing 4o g. of butter. The plasma concentration of griseofulvin were determined 1, 3, 5, 7, 9, 24, and 32 h. after dosing using a spectrofluorometric method, and pharmacokinetic parameters (Cp max, t max, AUC 0 - greater than 32) were calculated. These parameters were found to be; Cp max = 0.0.681 +/- 0.1 mu/ml, t max. = 2.51 +/- 0.33 h. and AUC = 14.14 +/- 2.33 micrograms h/ml for microsized tablets and Cp max = 0.80 +/- 0.08 +/- g/ml, t max = 2.44 +/- 0.54 and AUC = 16.25 +/- 1.16 microgram h/ml for ultramicrosized tablets. Our results show that mean peak plasma level and AUC (0 - greater than 32) are only slightly higher for the ultramicrosized preparation and the time to peak plasma level is similar in two preparations. Therefore, it is concluded that coadministration of griseofulvin with food will tend to reduce the difference between the bioavailability of the two type of preparations. 相似文献