全文获取类型
收费全文 | 7077篇 |
免费 | 384篇 |
国内免费 | 141篇 |
专业分类
耳鼻咽喉 | 107篇 |
儿科学 | 176篇 |
妇产科学 | 121篇 |
基础医学 | 933篇 |
口腔科学 | 501篇 |
临床医学 | 522篇 |
内科学 | 1672篇 |
皮肤病学 | 161篇 |
神经病学 | 611篇 |
特种医学 | 445篇 |
外国民族医学 | 1篇 |
外科学 | 707篇 |
综合类 | 59篇 |
一般理论 | 1篇 |
预防医学 | 679篇 |
眼科学 | 70篇 |
药学 | 510篇 |
中国医学 | 75篇 |
肿瘤学 | 251篇 |
出版年
2023年 | 59篇 |
2022年 | 123篇 |
2021年 | 214篇 |
2020年 | 136篇 |
2019年 | 174篇 |
2018年 | 226篇 |
2017年 | 134篇 |
2016年 | 211篇 |
2015年 | 208篇 |
2014年 | 289篇 |
2013年 | 346篇 |
2012年 | 472篇 |
2011年 | 529篇 |
2010年 | 308篇 |
2009年 | 219篇 |
2008年 | 379篇 |
2007年 | 387篇 |
2006年 | 334篇 |
2005年 | 302篇 |
2004年 | 223篇 |
2003年 | 192篇 |
2002年 | 156篇 |
2001年 | 146篇 |
2000年 | 147篇 |
1999年 | 120篇 |
1998年 | 121篇 |
1997年 | 119篇 |
1996年 | 119篇 |
1995年 | 91篇 |
1994年 | 70篇 |
1993年 | 79篇 |
1992年 | 66篇 |
1991年 | 84篇 |
1990年 | 62篇 |
1989年 | 96篇 |
1988年 | 72篇 |
1987年 | 79篇 |
1986年 | 47篇 |
1985年 | 69篇 |
1984年 | 32篇 |
1983年 | 31篇 |
1982年 | 27篇 |
1981年 | 24篇 |
1980年 | 33篇 |
1979年 | 15篇 |
1978年 | 26篇 |
1977年 | 25篇 |
1976年 | 32篇 |
1975年 | 30篇 |
1968年 | 16篇 |
排序方式: 共有7602条查询结果,搜索用时 16 毫秒
31.
Small rodents of the species Rattus norvegicus and Rattus rattus have been captured between 1986 and 1988 in several areas of Southern Portugal. A total of 135 animal specimens were examined for hantaviral antigens in lung sections and 5 have been found positive. Some of the rodents were shown to have serum antibodies as detected by immunofluorescence in titres up to 1:256. This investigation proves for the first time the presence of Hantavirus in wild rodent populations of Portugal. 相似文献
32.
Andres A; Morales JM; Praga M; Campo C; Lahera V; Garcia-Robles R; Rodicio JL; Ruilope LM 《Nephrology, dialysis, transplantation》1997,12(7):1437-1440
BACKGROUND: Cyclosporin has been shown to facilitate renal vasoconstriction
and to have an antinatriuretic effect. The existence of an interference of
cyclosporin with the vasodilating properties of endothelium mediated by
nitric oxide production could mediate these effects. On the other hand, the
infusion of the nitric oxide precursor L-arginine has been shown to induce
renal vasodilatation and to facilitate natriuresis in normal volunteers. We
have investigated the renal effects of the administration of an infusion of
L-arginine in renal transplant patients chronically treated with
cyclosporin. To facilitate the analysis of the data the effects of the
administration of a similar dose of cyclosporin on renal function during
the infusion of a vehicle were also investigated during the administration
of a vehicle of L-arginine. DESIGN: Ten male renal transplant patients,
chronically treated with cyclosporin and with a stable renal function were
studied during 2 consecutive days after the administration of the usual
morning dose of cyclosporin. The first day they received an intravenous
infusion of vehicle and the second the infusion of graded doses of
L-arginine (50, 100, 150 mg/kg/h) during 3 consecutive h. RESULTS: The
first day, after cyclosporin administration a significant fall (P <
0.01) was observed in natriuresis and kaliuresis in the absence of changes
in renal plasma flow and glomerular filtration rate. After the
administration of L-arginine significant (P < 0.01) increases of renal
plasma flow, glomerular filtration rate, and natriuresis were seen. The
increase in blood levels of cyclosporin after its administration did not
differ between days 1 and 2. CONCLUSION: These results indicate that
L-arginine facilitates renal vasodilatation and natriuresis in renal
transplant patients. Furthermore, the observed increase in sodium excretion
could indicate that L-arginine counteracts the antinatriuretic effect of
cyclosporin.
相似文献
33.
Daniel A Waschbusch Normand J Carrey Michael T Willoughby Sara King Brendan F Andrade 《Journal of clinical child and adolescent psychology》2007,36(4):629-644
This study examined whether response to behavior modification with and without methylphenidate differed for children with attention-deficit/hyperactivity disorder (ADHD) and conduct problems (CP) depending on the presence of callous/unemotional (CU) traits. Participants were 37 children ages 7 to 12, including 19 with ADHD/CP-only and 18 with ADHD/CP-CU, referred to a university-based summer treatment program. Results showed that ADHD/CP-CU children had worse behavior in the behavior-therapy-only (BT-only) condition, especially on measures of CP, noncompliance, and rule violations, but these differences largely disappeared when medication was added to BT. Children with ADHD/CP-CU were also less likely to be normalized by treatment than were children with ADHD/CP-only. These findings, though tentative, suggest that children with ADHD/CP-CU may not show a sufficient positive response to BT alone and that the combination of medication and BT may be especially important for them. 相似文献
34.
Effect of voice rehabilitation on oral communication of Parkinson's disease patients 总被引:3,自引:0,他引:3
E. C. de Angelis L. F. Mourao H. B. Ferraz M. S. Behlau P. A. L. Pontes L. A. F. Andrade 《Acta neurologica Scandinavica》1997,96(4):199-205
Voice and speech disorders are common in Parkinson's disease patients and may lead to social isolation. We employed routine clinical voice therapy measures to evaluate the effect of voice rehabilitation. Twenty patients with a stable drug regimen participated in this study. The patients were assessed before and after a program of voice rehabilitation consisting of 13 group therapy sessions during 1 month, with emphasis on the increase in laryngeal sphincteric activity. Voice rehabilitation produced an increase in maximal phonation times, decrease in the values of s/z ratio and air flow, increase in vocal intensity, decrease in the complaints of weak and strained-strangled voice and monotonous and unintelligible speech and elimination of complaints of swallowing alterations. These data indicate a greater glottic efficiency after voice rehabilitation reflecting a more functional oral communication. 相似文献
35.
Andrade C Gangadhar BN Subbakrishna DK Channabasavanna SM Pradhan N 《Convulsive therapy》1988,4(4):297-305
In a double-blind prospective study, 29 endogenously depressed patients (RDC) were randomized into sinusoidal wave (SW) and brief-pulse (BP) electroconvulsive therapy (ECT) groups. Bilateral modified treatments were administered on alternate days, three per week, and the treatment variables of current dosage and seizure duration were monitored for each treatment. Significantly more patients responded to SW than to BP ECT, but a comparable number of treatments was required to produce this response in the two groups. There was no difference in clinical or treatment variables between the SW and the BP groups, nor between ECT responders and nonresponders, with the exception that the SW-treated patients received larger doses of current per treatment than did the BP patients. For endogenous depression treated with ECT, we conclude that cumulative seizure duration may not be a parameter of significance, that overall rate of recovery in ECT responders is independent of stimulus waveform, and that some depressives may respond to SW but not to BP ECT. We suggest that the antidepressant effect of the ECT seizure may be characterized by a therapeutic window in current requirements; alternatively, a putative response threshold (again in terms of current requirement) may exist, which is higher in some patients than in others. 相似文献
36.
Thirty-two endogenous depressed patients (RDC) were treated with electroconvulsive therapy. Four patients (12.5%) developed a transient manic reaction; in two cases, this reaction occurred in mid-depression. Mania is not a generally recognized side effect of ECT; we detail the clinical characteristics, but fail to define clinical predictors of vulnerability. 相似文献
37.
Image-directed percutaneous biopsies with a biopsy gun 总被引:3,自引:0,他引:3
Core tissue for histologic study is believed by many pathologists to be more diagnostic than material from needle aspiration. Recently, a biopsy "gun" has been introduced, which simplifies core biopsies. With this device, 182 biopsies of multiple anatomic sites were performed with ultrasonic, computed tomographic, and fluoroscopic guidance and 18-gauge needles. High-quality histopathologic specimens were obtained in 177 of the biopsies, and diagnostic target tissue was obtained in 167. Only three significant complications occurred: one bleeding complication that required transfusion and two cases of pneumothorax that necessitated placement of chest tubes. The biopsy gun eliminated the disjointed movements of conventional "skinny" needle biopsies, and none of the samples demonstrated significant "crush" artifact or obscuring blood, problems that are commonly associated with manual biopsy techniques. Patient discomfort was decreased with this system compared with that of manual biopsies, and the total procedure time was reduced. Because of these distinct advantages, the authors now use the biopsy gun exclusively for all percutaneous biopsies and recommend that other institutions consider the use of this biopsy method. 相似文献
38.
新生期大白鼠皮下注射谷氨酸单钠对成年后下丘脑α-促黑素细胞激素神经元免疫反应性的影响 总被引:2,自引:0,他引:2
本文用免疫组化方法研究了新生期大白鼠注射谷氨酸单钠(MSG)对成年后下丘脑α-促黑素细胞激素(α-MSH)免疫反应神经元的影响,结果显示MSG处理以后下丘脑弓状核区α-MSII免疫反应神经元减少甚至完全消失,但不影响下丘脑背外侧区的α-MSH神经元群。文中还讨论了这两群α-MSH神经元的生理作用。 相似文献
39.
de Andrade AL Pimenta FC Laval CA de Andrade JG Guerra ML Brandileone MC 《Journal of clinical microbiology》2004,42(5):2345-2346
We present a case of invasive pneumococcal infection in a healthy 10-month-old infant from whom Streptococcus pneumoniae serotype 23F was isolated from the blood and serotype 23B was isolated from the cerebrospinal fluid. Both serotypes were penicillin nonsusceptible. Pulsed-field gel electrophoresis analysis demonstrated that the two serotypes had distinct DNA patterns, indicating that infection did not occur as a result of capsular transformation but as a result of a mixed infection with two distinct pneumococcal serotypes. 相似文献
40.
Linkage of the MHC to familial multiple sclerosis suggests genetic heterogeneity. The Multiple Sclerosis Genetics Group 总被引:5,自引:0,他引:5
Haines JL; Terwedow HA; Burgess K; Pericak-Vance MA; Rimmler JB; Martin ER; Oksenberg JR; Lincoln R; Zhang DY; Banatao DR; Gatto N; Goodkin DE; Hauser SL 《Human molecular genetics》1998,7(8):1229-1234
Multiple sclerosis (MS) is a demyelinating autoimmune disease of the
central nervous system. While its etiology is not well understood, genetic
factors are clearly involved. Until recently, most genetic studies in MS
have been association studies using the case-control design testing
specific candidate genes and studying only sporadic cases. The only
consistently replicated finding has been an association with the HLA-DR2
allele within the major histocompatibility complex (MHC) on chromosome 6.
Using the genetic linkage design, however, evidence for and against linkage
of the MHC to MS has been found, fostering suggestions that sporadic and
familial MS have different etiologies. Most recently, two of four genomic
screens demonstrated linkage to the MHC, although specific allelic
associations were not tested. Here, a dataset of 98 multiplex families was
studied to test for an association to the HLA-DR2 allele in familial MS and
to determine if genetic linkage to the MHC was due solely to such an
association. Three highly polymorphic markers (HLA-DR, D6S273 and TNFbeta)
in the MHC demonstrated strong genetic linkage (parametric lod scores of
4.60, 2.20 and 1.24, respectively) and a specific association with the
HLA-DR2 allele was confirmed (TDT; P < 0.001). Stratifying the results
by HLA-DR2 status showed that the linkage results were limited to families
segregating HLA-DR2 alleles. These results demonstrate that genetic linkage
to the MHC can be explained by the HLA-DR2 allelic association. They also
indicate that sporadic and familial MS share a common genetic
susceptibility. In addition, preliminary calculations suggest that the MHC
explains between 17 and 62% of the genetic etiology of MS. This
heterogeneity is also supported by the minority of families showing no
linkage or association with loci within the MHC.
相似文献