全文获取类型
收费全文 | 4430篇 |
免费 | 390篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 131篇 |
妇产科学 | 62篇 |
基础医学 | 700篇 |
口腔科学 | 115篇 |
临床医学 | 532篇 |
内科学 | 860篇 |
皮肤病学 | 187篇 |
神经病学 | 127篇 |
特种医学 | 342篇 |
外科学 | 667篇 |
综合类 | 106篇 |
一般理论 | 3篇 |
预防医学 | 391篇 |
眼科学 | 93篇 |
药学 | 375篇 |
中国医学 | 3篇 |
肿瘤学 | 143篇 |
出版年
2021年 | 46篇 |
2015年 | 55篇 |
2014年 | 68篇 |
2013年 | 132篇 |
2012年 | 120篇 |
2011年 | 85篇 |
2010年 | 81篇 |
2009年 | 78篇 |
2008年 | 82篇 |
2007年 | 131篇 |
2006年 | 134篇 |
2005年 | 102篇 |
2004年 | 88篇 |
2003年 | 104篇 |
2002年 | 95篇 |
2001年 | 105篇 |
2000年 | 87篇 |
1999年 | 86篇 |
1998年 | 104篇 |
1997年 | 110篇 |
1996年 | 129篇 |
1995年 | 79篇 |
1994年 | 96篇 |
1993年 | 85篇 |
1992年 | 109篇 |
1991年 | 98篇 |
1990年 | 96篇 |
1989年 | 126篇 |
1988年 | 111篇 |
1987年 | 112篇 |
1986年 | 100篇 |
1985年 | 81篇 |
1984年 | 108篇 |
1983年 | 58篇 |
1982年 | 61篇 |
1981年 | 65篇 |
1980年 | 87篇 |
1979年 | 75篇 |
1978年 | 73篇 |
1977年 | 63篇 |
1976年 | 61篇 |
1975年 | 73篇 |
1972年 | 61篇 |
1970年 | 56篇 |
1969年 | 48篇 |
1965年 | 60篇 |
1964年 | 58篇 |
1963年 | 53篇 |
1962年 | 46篇 |
1960年 | 68篇 |
排序方式: 共有4852条查询结果,搜索用时 24 毫秒
31.
J. A. D. Anderson Carole Buck Kate Danaher John Fry 《The British journal of general practice》1977,27(176):155-159
Sixty patients who visited their general practitioner were matched with 60 patients registered with the same doctor, who were of the same sex and in the same ten-year age group, and who had not visited the doctor for at least one year, but had recently experienced symptoms similar to those presented by the attending patients.
Comparison of the 60 pairs revealed the following differences, all substantial although not all statistically significant. The patients who visited the doctor perceived themselves as less healthy, fewer had attempted self-treatment, more reported serious personal problems, and fewer reported obstacles to visiting the doctor.
Differences between the pairs were negligible for total number of current ailments, effectiveness of self-treatment, if used, optimism about the healing powers of doctors, and fear of troubling their doctor with trivia.
相似文献32.
33.
34.
We have developed a sandwich-type ELISA system for measuring total IgD levels in the serum of atopics and non-atopic controls. In this ELISA system, affinity purified goat anti-human IgD was used for capture. Results were superior to those obtained with monoclonal anti-human IgD antibody. No cross-reactivity could be demonstrated to IgG, IgM, IgA or IgE. The assay showed minimal non-specific binding even with initial serum dilutions of 1:2. The results obtained were reproducible among replicates (Mean CV +/- SEM = 0.03 +/- 0.002; n = 251), between dilutions (CV = 0.08 +/- 0.006; n = 108), and between assays (CV = 0.05 +/- 0.12; n = 5). We used routine radioimmunoassay for measuring total serum IgE. Using these assays total serum IgD and IgE levels were measured in 75 atopic patients and 33 normal subjects. None of the atopics had recent immunotherapy. As expected, the geometric mean serum IgE in atopics (373 ng/ml) was significantly higher than that in normal subjects (49 ng/ml) (P less than 0.01). However, geometric mean serum IgD was also significantly higher in atopics (20.3 micrograms/ml) than that in normal subjects (8.4 micrograms/ml) (P less than 0.02). In both atopic and normal groups, mean serum IgD level did not differ significantly on the bases of age, sex or asthmatic status. Furthermore, total serum IgD was not significantly correlated with total serum IgE (r = 0.14; P = 0.14; n = 108), indicating that immunoregulatory control of the basal levels of the two isotypes is not linked.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
35.
Mahadevaiah SK; Odorisio T; Elliott DJ; Rattigan A; Szot M; Laval SH; Washburn LL; McCarrey JR; Cattanach BM; Lovell-Badge R; Burgoyne PS 《Human molecular genetics》1998,7(4):715-727
An RNA-binding motif (RBM) gene family has been identified on the human Y
chromosome that maps to the same deletion interval as the 'azoospermia
factor' (AZF). We have identified the homologous gene family (Rbm) on the
mouse Y with a view to investigating the proposal that this gene family
plays a role in spermatogenesis. At least 25 and probably >50 copies of
Rbm are present on the mouse Y chromosome short arm located between Sry and
the centromere. As in the human, a role in spermatogenesis is indicated by
a germ cell-specific pattern of expression in the testis, but there are
distinct differences in the pattern of expression between the two species.
Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are
female due to a position effect resulting in non-expression of Sry ;
sex-reversing such mice with an Sry transgene produces males with a high
incidence of abnormal sperm, making this the third deletion interval on the
mouse Y that affects some aspect of spermatogenesis. Most of the copies of
Rbm map to this deletion interval, and the Yd1males have markedly reduced
Rbm expression, suggesting that RBM deficiency may be responsible for, or
contribute to, the abnormal sperm development. In man, deletion of the
functional copies of RBM is associated with meiotic arrest rather than
sperm anomalies; however, the different effects of deletion are consistent
with the differences in expression between the two species.
相似文献
36.
Histochemical methods are routinely used to delineate skeletal muscle fiber types. In the present investigation, this qualitative determination of fiber type composition was compared to the electrophoretically determined myosin heavy chain (MHC) content from a large number of human muscle biopsy samples. Biopsies were taken from the vastus lateralis muscle at the beginning and every 2 weeks during 8 weeks of highi-ntensity resistance training from men (n = 13) and woman (n = 8). Muscle was also extracted from nontraining men (n = 7) and women (n = 5) at the same periods. Six muscle fiber types (I, IC, IIAC, IIA, IIAB, and IIB) were determined using basic myofibrillar adenosine triphosphatase histochemistry. Cross-sectional areas were determined for the three major fiber types (I, IIA, and IIB) and used to calculate the percentage area of these types. Electrophoretic techniques were used to separate and quantify the percentage MHC content in these same biopsy samples, and these data were then used to compare with the percentage fiber type area. Correlation analyses suggest a relationship between the histochemically assessed percentage fiber type area and the electrophoretically assessed MHC content in human limb musculature. However, because of possible histochemical misclassification of some fibers (especially in trained muscle) both techniques may be essential in yielding important information about fiber type composition and possible fiber type transformations. 相似文献
37.
Peter A. Shapiro Richard P. Sloan Emilia Bagiella J. Thomas Bigger JR. Jack M. Gorman 《Psychophysiology》1996,33(1):54-62
Heart rate reactivity to mental stress is substantially blunted early after heart transplantation, suggesting that the loss of neural modulation limits the cardiovascular response to mental stress. We tested whether reactivity to mental stress recovers during the first year after heart transplantation. Hemodynamic and respiratory responses to mental arithmetic challenge were studied in 20 heart transplant recipients 3, 6, and 12 months after surgery. A normal comparison group was studied at equivalent intervals. Heart rate reactivity to mental arithmetic was significantly reduced in the cardiac transplant group compared to the normal subjects. This effect persisted up to 1 year after transplantation. Heart period variability in the heart transplant recipients was minimal in all three-test sessions. The findings suggest that no functional reinnervation or other compensatory adaptation occurs up to 1 year after heart transplantation. 相似文献
38.
IgG antibody to gE, the Fc gamma-binding herpes simplex 1 (HSV-1) viral glycoprotein, was studied in 49 rheumatoid arthritis (RA) patients and 43 normal controls. Antibody to gD, another important HSV-1 antigen, was assayed in parallel. No difference between RA patients and normal controls was found in levels of anti-gE antibody measured by reactivity of IgG F(ab')2 fragments reacting with gE coated to ELISA plates. No difference in anti-gD antibody was recorded between normals and patients with RA. Levels of IgG anti-IgE antibody did not correlate with quantitative elevations of serum rheumatoid factor (RF) in RA patients. When IgG anti-gE and anti-gD were assayed in 20 patients with juvenile rheumatoid arthritis and 22 children controls, no significant differences were noted. However, when individual RFs from patients with RA were tested for reactivity against a panel of affinity-isolated F(ab')2 antibodies to gE, some evidence for individual autospecificity was obtained. Four of 20 monoclonal IgM RFs produced from RA patients' B cells showed marked elevations of reactivity with some RA patients' F(ab')2 antibodies to gE. All four of the monoclonal RFs showing this specificity were derived from RA synovial tissue B cells. These findings may provide support for the concept that some RFs in patients with RA show individual specificity for internal image determinants of IgG antibodies to viral Fc gamma-binding proteins. 相似文献
39.
40.
Lu Y Condie A Bennett JD Fry MJ Yuille MR Shipley J 《Cancer Genetics and Cytogenetics》2001,126(2):97-101
Mutations in the ATM gene, which maps to 11q22-23, cause the multisystem recessive syndrome ataxia-telangiectasia (AT). Breast cancer has been reported in AT patients and carriers. Sporadic breast cancer is associated with loss of heterozygosity at or in the region of ATM and chromosomal abnormalities involving 11q23. We have investigated the chromosomes, nuclei and released chromatin fibers from nine primary breast carcinoma and eight cell lines by fluorescence in situ hybridization with four fluorochrome-labeled cosmids spanning the ATM gene. The ATM gene was disrupted in one primary breast carcinoma and in the cell lines MDA-MB-231 and MCF-7. The role of these aberrations in breast carcinomas, which may lead to gene dosage or dominant negative effects on gene function, requires further investigation. 相似文献