全文获取类型
收费全文 | 134424篇 |
免费 | 11699篇 |
国内免费 | 8643篇 |
专业分类
耳鼻咽喉 | 1394篇 |
儿科学 | 1829篇 |
妇产科学 | 1146篇 |
基础医学 | 13425篇 |
口腔科学 | 2382篇 |
临床医学 | 15294篇 |
内科学 | 19724篇 |
皮肤病学 | 1524篇 |
神经病学 | 6811篇 |
特种医学 | 5615篇 |
外国民族医学 | 37篇 |
外科学 | 15354篇 |
综合类 | 24971篇 |
现状与发展 | 34篇 |
一般理论 | 13篇 |
预防医学 | 10831篇 |
眼科学 | 2557篇 |
药学 | 13766篇 |
126篇 | |
中国医学 | 7701篇 |
肿瘤学 | 10232篇 |
出版年
2024年 | 408篇 |
2023年 | 1537篇 |
2022年 | 4059篇 |
2021年 | 5693篇 |
2020年 | 4261篇 |
2019年 | 3620篇 |
2018年 | 3740篇 |
2017年 | 3929篇 |
2016年 | 3793篇 |
2015年 | 5812篇 |
2014年 | 7504篇 |
2013年 | 7512篇 |
2012年 | 11188篇 |
2011年 | 11953篇 |
2010年 | 9120篇 |
2009年 | 7677篇 |
2008年 | 9082篇 |
2007年 | 9015篇 |
2006年 | 8144篇 |
2005年 | 7549篇 |
2004年 | 5531篇 |
2003年 | 5249篇 |
2002年 | 4419篇 |
2001年 | 2839篇 |
2000年 | 2367篇 |
1999年 | 1759篇 |
1998年 | 1142篇 |
1997年 | 1107篇 |
1996年 | 802篇 |
1995年 | 742篇 |
1994年 | 640篇 |
1993年 | 409篇 |
1992年 | 403篇 |
1991年 | 340篇 |
1990年 | 258篇 |
1989年 | 198篇 |
1988年 | 182篇 |
1987年 | 143篇 |
1986年 | 148篇 |
1985年 | 90篇 |
1984年 | 80篇 |
1983年 | 52篇 |
1982年 | 38篇 |
1981年 | 28篇 |
1980年 | 29篇 |
1979年 | 22篇 |
1978年 | 22篇 |
1975年 | 18篇 |
1973年 | 17篇 |
1972年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Susumu Akimoto Koichiro Akakura Takemasa Ohki Jun Shimazaki 《International journal of urology》1994,1(3):263-267
To compare levels of y-seminoprotein (gM-Sm) assayed by original and revised assay systems, blood was obtained every 4 h over a 32-h period from 8 untreated prostate cancer patients. Serum levels of prostate specific antigen (PSA) were also examined. In 6 patients, the coefficient of variation (CV) of the serum levels assayed by the revised assay was significantly different from that of the intra-assay samples. In contrast, the CV of the gM-Sm serum levels assayed by the original assay differed significantly from that of the intra-assay samples in only 2 patients. The fluctuations in gM-Sm assayed by the revised assay were, at least in part, similar to those of the PSA serum levels in all patients. The mean CV of the gM-Sm serum levels assayed by the revised assay was significantly larger than that for levels measured by the original assay. After treatment, the rate of decrease in gM-Sm serum levels determined by the original assay differed from that in the serum levels of PSA and prostatic acid phosphatase. These results indicate that the original assay for gM-Sm do not detect diurnal differences in serum gM-Sm levels, even at levels below 20 ng/ml. These observations indicate that the analysis of data obtained using the original gM-Sm kit should be interpreted with caution. 相似文献
52.
53.
Fluid-fluid levels in cavernous hemangioma of soft tissue 总被引:3,自引:0,他引:3
Shigeru Ehara M.D. Miyuki Sone Yoshiharu Tamakawa Jun Nishida Masataka Abe Junichi Hachiya 《Skeletal radiology》1994,23(2):107-109
Five cases of cavernous hemangioma with fluid-fluid levels on magnetic resonance imaging and/or computed tomography are reported. The signal characteristics were those of blood and histological analysis of the fluid-fluid levels showed that they were blood-filled cavities in the tumor. Although this finding itself is not specific, it may help in confirming the diagnosis of cavernous hemangioma. 相似文献
54.
The knee meniscus exhibits extensive spatial variations in native healing capacity, biochemical composition, and cell morphology that suggest the existence of distinct phenotypes for meniscus cells. Constitutive gene expression levels of appropriate extracellular matrix proteins may serve as useful molecular markers of cellular phenotypes; however, relatively little is known of variations in the gene expression for meniscus cells of different regions of the tissue. The objective of the present study was to evaluate constitutive differences between radial inner and outer regions in gene expression for extracellular matrix proteins relevant to the meniscus. A secondary objective was to determine if these region-specific differences in gene expression are maintained after periods of monolayer culture. The innermost regions of the meniscus were found to constitutively express higher mRNA levels for proteins highly expressed in articular cartilage, including aggrecan, type II collagen, and NOS2. In contrast, the outer meniscus was found to contain higher gene expression for proteins associated with fibrous tissues including type I collagen, and the proteases MMP2 and MMP3. Isolated inner and outer meniscus cells maintained these region-specific gene expression patterns for collagens and proteoglycans during short-term monolayer culture. The results provide new information that suggests the utility of constitutive gene expression levels as molecular markers to distinguish tissue and cells of the inner and outer meniscus. 相似文献
55.
Shinji Homma Kenji Satoh Hitoshi Matsuo Minoru Yagi Jun Hasegawa Tomoyuki Maruta Naozumi Watanabe Tsuneo Iiai Katsuyoshi Hatakeyama 《Journal of Smooth Muscle Research》2004,40(6):271-280
Electrogastrograms (EGGs) were recorded in patients both before and after receiving proximal gastrectomy plus jejunal interposition (PGJI) or just after receiving total gastrectomy plus jejunal interposition (TGJI). Intraluminal pressure was also recorded in some postoperative patients. The EGG 3 cpm component (2.5-4.9 cpm) remained after PGJI, but subsequently decreased with a significant reduction in the preoperative to postoperative ratio of the 3 cpm components (P<0.05). The mean frequency of the 3 cpm components increased significantly after PGJI (P<0.05) and its instability factor increased. The EGG 10 cpm components became relatively dominant compared to other frequency components in 2 out of 8 of patients having PGJI but the mean amplitude of 10 cpm decreased. In TGJI patients, only the 10 cpm component was conspicuous in EGG as in the case of total gastrectomy and Roux en Y anastomosis procedures. The spectral frequencies of intraluminal pressure in the interposed jejunum were similar to the EGG of 10 cpm components both in the case of PGJI and TGJI patients. In conclusion, surface EGG could record the electrical activities of the interposed jejunum more easily in patients having had TGJI than in PGJI. 相似文献
56.
J. R. D. Matthews I. A. Cooper J. P. Matthews J. CHONG Ding 《Internal medicine journal》1992,22(2):123-128
In an attempt to improve response and survival rates in patients with non-Hodgkin's lymphoma, a relatively intense six drug regimen MATCOP was developed comprising four-weekly cycles of methotrexate (100mg/m2, IVY day 8), Adriamycin (30mg/m2, IVY days 1,2), teniposide (75 mg/rn2, IV, day 1), cyclophophamide (300 mg/m2, po, days one to five), Oncovin (1.4 mg/m2, IV: maximum 2 mg, days 8,15) and prednisolone (100 mg, po, days one to five). A randomised trial was conducted comparing MATCOP with the standard CHOP regimen, comprising three-weekly cycles of cyclophosphamide (750 mg/m2, IV, day 1), Adriamycin (50 mg/m2, IV, day 1), Oncovin (1.4 mg/m2 IV: maximum 2 mg, day 1) and prednisolone (100 mg, PO, days two to six). Eighty patients with large cell lymphoma, diffuse mixed small cleaved and large cell lymphoma or diffuse small cleaved cell lymphoma were randomised, 47 to MATCOP and 33 to CHOP. MATCOP patients experienced increased granulocytopenia, thrombocytopenia (p 0.0001), mucositis (p= 0.002) and infections (p= 0.01) compared to CHOP patients. Complete response rates were similar: 66% for MATCOP patients and 61% for CHOP patients. There were no apparent differences in the time to relapse for patients achieving CR, the time to treatment failure or the overall survival time. Thus despite an increase in toxicity, the more intense regimen MATCOP failed to confer any therapeutic benefit compared with the standard CHOP regimen. Survival was not influenced but toxicity was increased by dose intensification. (Aust NZ J Med 1992; 22: 123–128.) 相似文献
57.
乳腺囊性增生病癌变过程中部分因素变化的意义 总被引:3,自引:0,他引:3
检测乳腺囊性增生病(FCD)经不典型增生到癌变部分因素的变化。结果提示:从因明显FCD症状活检至癌变为2~10年;从Ⅱ级以上不典型增生到临床癌变需2~7年;癌变率为3.1%。FCD患者存在性激素分泌调控失常,血浆雌激素和催乳素含量增加,导致上皮细胞增生。乳腺一般性增生细胞的DNA含量和超微结构与正常乳腺上皮细胞相似;无肿瘤相关抗原及异常基因产物表达。而发生在一般性增生基础上的不典型增生则呈现细胞基因物质DNA含量增加,部分为超4C的多倍体细胞;同时出现细胞膜和细胞核超微结构异常;雌激素受体含量增加,对性激素的依赖性和敏感性增强;部分不典型增生细胞出现胚胎性肿瘤相关抗原和异常基因产物表达。随不典型增生程度加重至乳腺癌,上述诸因素的变化趋势具有明显规律性。提示FCD上皮细胞从一般性增生经不典型增生至乳腺癌为细胞生物学连续逐渐变化的过程。部分不典型增生细胞中具有癌倾向的细胞生物学行为异常和表型变化与乳腺癌发生密切相关。细胞核DNA含量等异常变化及程度可作为乳腺癌前病变发展程度的客观标志 相似文献
58.
Jun Gu Yang O Huh Feng Jiang Nancy P Caraway Jorge E Romaguera Tanweer M Zaidi Ricardo L Fernandez Huazhong Zhang Issa F Khouri Ruth L Katz 《Modern pathology》2004,17(5):553-560
Mantle cell lymphoma is non-Hodgkin's B-cell lymphoma characterized by the t(11;14)(q13;q32) translocation. Peripheral blood involvement of mantle cell lymphoma is usually associated with a poor prognosis and therefore, its identification is clinically important. In this study, we performed cyclin D1/IgH-probe fusion fluorescence in situ hybridization analysis on 223 peripheral blood samples: 185 from 125 mantle cell lymphoma patients, and 38 normal controls. The cutoff values for the test were established using normal controls. Flow cytometry on peripheral blood and corresponding bone marrow samples was used to evaluate this test. In all, 26% of the 185 peripheral blood samples and 27% of the 161 corresponding bone marrow samples were flow cytometry positive for mantle cell lymphoma. The mean numbers of single and- double-fusion signals and the mean number of CD5/CD19-positive cells, absolute blood lymphocyte count, and white blood cell count were significantly higher in peripheral blood and corresponding bone marrow samples with mantle cell lymphoma-positive flow cytometry. Double-fusion signals were more specific than single-fusion ones. Fluorescence in situ hybridization was far more likely to be positive for mantle cell lymphoma when the peripheral blood and the corresponding bone marrow samples had positive flow cytometry results or morphology (P<0.01). Our study indicates that cyclin D1/IgH-fusion fluorescence in situ hybridization analysis could be used to determine the presence and character of circulating mantle cell lymphoma cells in peripheral blood, thus enhancing our ability to evaluate leukemic mantle cell lymphoma and minimum residual disease. 相似文献
59.
结核分枝杆菌Ag85B/GST融合蛋白表达载体构建及在大肠杆菌中的表达 总被引:1,自引:1,他引:0
目的 构建结核分枝杆菌Ag85B/GSF融合蛋白表达质粒,并在大肠杆菌(E.coli)中诱导表达。方法 以质粒pUC18/Ag85B为模板,用PCR法扩增结核杆菌Ag85B基因,扩增的Ag85B上游含有EcoR Ⅰ酶切位点,下游含有SalⅠ酶切位点;将Ag85B基因定向插入质粒pGEX-4T-1中,构建原核表达质粒pGEX-Ag85B并转化E.coli B121,筛选阳性重组子,限制性内切酶切鉴定和DNA序列测定,异丙基硫代半乳糖苷(IPTG)诱导表达,SDS-PAGE和Westem blot鉴定结果。结果 成功构建原核表达质粒pGEX-Ag85B并表达出Mr约56000大小的Ag85B/GSY融合蛋白,表达量占总菌体的30%。结论 为进一步进行纯化Ag85B蛋白和研究其在膀胱肿瘤治疗中的作用奠定了基础。 相似文献
60.
Tokihisa Nagai Yasuharu Tabara Michiya Igase Jun Nakura Tetsuro Miki Katsuhiko Kohara 《Hypertension research》2007,30(7):577-583
Migraine is a common subtype of headache. Epidemiological studies have revealed that migraine could be an independent risk factor for ischemic stroke even in elderly subjects. Arterial stiffness is one of the major pathophysiological bases of stroke. In the present study, we cross-sectionally investigated the possible relationship between migraine and arterial stiffness in community-dwelling subjects. The study subjects were independently recruited from two sources (Group A, n=134, 68+/-5 years; Group B, n=138, 68+/-7 years). Augmentation index (AI), the ratio of augmented pressure by the reflection pressure wave to the pulse pressure, was obtained from the radial arterial waveform as an index of arterial stiffness. Brachial blood pressure was also measured simultaneously. Migraine was diagnosed using a previously validated questionnaire. The prevalence of migraine was 5.2% (Group A) and 16.7% (Group B). Subjects with migraine had higher radial AI in both Group A (migraine, 101+/-15%; other headache, 88+/-12%; no headache, 86+/-12%, p=0.003) and Group B (95+/-11%, 90+/-11%, 91+/-14%, p=0.058). Multiple linear regression analysis revealed that migraine was an independent determinant of AI (beta=0.154, p=0.002) after adjustment for other confounding factors: age (beta=-0.024, p=0.654); sex (beta=0.141, p=0.069); body height (beta=-0.215, p=0.005); systolic blood pressure (beta=0.174, p=0.001); medication for hypertension, hyperlipidemia, and diabetes mellitus (beta=-0.014, p=0.787); and heart rate (beta=-0.539, p<0.001). In a separate analysis by sex, migraine was also a significant determinant for AI (male, beta=0.246, p=0.019; female, beta=0.159, p=0.008). Migraine in the elderly could be a clinical manifestation of enhanced arterial stiffness. 相似文献