全文获取类型
收费全文 | 172590篇 |
免费 | 15357篇 |
国内免费 | 11101篇 |
专业分类
耳鼻咽喉 | 1832篇 |
儿科学 | 2186篇 |
妇产科学 | 1427篇 |
基础医学 | 17567篇 |
口腔科学 | 3171篇 |
临床医学 | 20222篇 |
内科学 | 24899篇 |
皮肤病学 | 2028篇 |
神经病学 | 8238篇 |
特种医学 | 6728篇 |
外国民族医学 | 67篇 |
外科学 | 19108篇 |
综合类 | 32178篇 |
现状与发展 | 43篇 |
一般理论 | 23篇 |
预防医学 | 14014篇 |
眼科学 | 3759篇 |
药学 | 17773篇 |
182篇 | |
中国医学 | 10120篇 |
肿瘤学 | 13483篇 |
出版年
2024年 | 561篇 |
2023年 | 2135篇 |
2022年 | 5591篇 |
2021年 | 7752篇 |
2020年 | 5814篇 |
2019年 | 4789篇 |
2018年 | 5119篇 |
2017年 | 5055篇 |
2016年 | 4887篇 |
2015年 | 7696篇 |
2014年 | 9602篇 |
2013年 | 9393篇 |
2012年 | 13890篇 |
2011年 | 15005篇 |
2010年 | 11323篇 |
2009年 | 9478篇 |
2008年 | 11049篇 |
2007年 | 11071篇 |
2006年 | 10234篇 |
2005年 | 9402篇 |
2004年 | 6995篇 |
2003年 | 6538篇 |
2002年 | 5527篇 |
2001年 | 3798篇 |
2000年 | 3180篇 |
1999年 | 2565篇 |
1998年 | 1703篇 |
1997年 | 1650篇 |
1996年 | 1175篇 |
1995年 | 1137篇 |
1994年 | 976篇 |
1993年 | 584篇 |
1992年 | 590篇 |
1991年 | 527篇 |
1990年 | 438篇 |
1989年 | 367篇 |
1988年 | 300篇 |
1987年 | 279篇 |
1986年 | 215篇 |
1985年 | 162篇 |
1984年 | 117篇 |
1983年 | 64篇 |
1982年 | 53篇 |
1981年 | 49篇 |
1980年 | 29篇 |
1979年 | 39篇 |
1978年 | 19篇 |
1975年 | 16篇 |
1973年 | 16篇 |
1972年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Whole pancreas isografts or allografts (ACI donors, RT1a) with bladder drainage of exocrine secretions were performed in Lewis rats (RR1(1] with streptozotocin-induced diabetes. Urinary amylase, pH, and volume and serum glucose were measured daily. They were analyzed alone, or in combination, to determine patterns in deviations from normal values, from isograft control values, or from a posttransplant baseline in relation to rejection (defined as reversion of plasma glucose of greater than 200 mg/dl) in nonimmunosuppressed recipients. Also studied were the sensitivity and specificity by which such deviations predicted rejection. Functioning grafts were associated with increased urinary amylase and pH compared with normal or diabetic controls; urinary volume was less than that of diabetic rats, but greater than that of normal rats. In nonimmunosuppressed allograft recipients (n = 9), rejection occurred at a mean (+/- SD) of 7.78 +/- 0.44 days. Serum glucose rose to above normal (greater than 134 mg/dl) 1 day before rejection in 3 animals (sensitivity 33%, false negative rate 66%; false positive rate in 9 isograft recipients, 44%). Urinary volume dropped below 3 ml at a mean of 3.17 +/- 0.98 days (range 2-5 days) before rejection in 6 animals (sensitivity 66%, false negative rate 33%; false positive rate 0%). Urinary pH fell below 7.25 at a mean of 3.13 +/- 1.81 days (range 1-5 days) before rejection in 8 rats (sensitivity of 89%, false negative rate 11%; false positive rate 29%). Urinary amylase dropped from a posttransplant peak at a mean of 3.56 +/- 1.42 days (range 1-6 days) before rejection in 9 animals (sensitivity 100%, false negative rate 0%; false positive rate 43%), and dropped below 1500 units per 24 hr at a mean of 2.00 +/- 1.32 days (range 1-5 days) before rejection in 8 animals (sensitivity 89%, false negative rate 11%; false positive rate 0%). A drop in urinary amylase combined with a drop in urinary volume or pH occurred at a mean of 3.22 +/- 1.48 days (range 1-5 days) before rejection in 9 rats (sensitivity 100%, false negative rate 0%; false positive rate 0%). In a separate group of 10 allograft recipients, immunosuppression with prednisone and cyclosporine was begun concomitant with, or within 2 days of, the drop in urinary amylase from the peak value; rejection did not occur in 3 animals and was delayed to a mean of 12.0 +/- 5.0 days posttransplant in 7 animals (P less than .05 compared with the nonimmunosuppressed group).(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
92.
用Warthin-Starry螺旋体特殊染色法及透射电镜观察,分别在19例肉芽肿性唇炎和5例梅罗综合征(MRS)病人的病变组织内发现有螺旋体存在,并对其在光,电镜下的形态和在病变组织内的分布部位进行了描述。经用大刘量青霉素治疗11例病人,10例有效。本结果为MRS的发可能和螺旋体感染有关的推测提供了依据。 相似文献
93.
应用电子自旋共振波谱仪(ESR)直接检测了缺血-再灌注兔心肌肌浆网自由基的变化,以探讨肌质网系统与氧自由基的关系。实验中将20只兔随机分为再灌注对照组、超氧化物歧化酶(SOD)组、ATP-氯化镁组和人参皂甙Re组。实验结果,g值2.0046处为半醌自由基波谱,其相对浓度各组依次为78.94±2.126,14.46±2.86,20.65±7.65,14.66±3.67(x±SD),对照组与用药组均有显著性差异(P<0.05),表明缺血-再灌注兔心肌肌浆网产生大量的自由基,用ESR可以直接检测到半醌自由基,外源性高能磷酸盐制剂ATP-氯化镁及人参皂甙Re与超氧化物歧化酶一样,发挥清除兔心肌肌浆网自由基的作用。 相似文献
94.
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
95.
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
96.
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
97.
Pulse-height and time spectra of afterpulses from a scintillation detector with NE102A scintillator sandwiching a 60Co source were observed at several different temperatures. From time analysis with a slow amplifier followed by a conventional TAC, spurious pulses are grouped into two types; time-dependent afterpulses and random noise. The intensity of afterpulses decreased considerably with increasing temperature, while the intensity of random noise pulses increased abruptly above 50 degrees C. Experiments, in which the temperatures of scintillator sheets and of the photomultiplier tube were changed separately, suggested that the time-dependent afterpulses were produced in the scintillator itself, while the random component arose from photomultiplier tube. 相似文献
98.
Katsumi Kimura Naotaka Fujita Yutaka Noda Go Kobayashi Kei Ito Jun Horaguchi Toshiki Sugawara Osamu Takasawa 《Digestive endoscopy》2004,16(1):54-57
Clinical diagnosis of chronic cholecystitis is made based on diffuse hyperechoic thickening of the gallbladder wall as shown by ultrasonographic examination. We herein report three cases of chronic cholecystitis showing localized hypoechoic thickening of the gallbladder wall that mimicked gallbladder cancer by ultrasonography. Histologically, hypertrophy of the muscularis propria was a common characteristic finding in these three patients. A smooth surface of the inner hypoechoic layer of the thickened wall was considered to be a reliable finding in the differential diagnosis between this type of chronic cholecystitis and gallbladder cancer. 相似文献
99.
100.
Shang Wen Chen Ji An Liang Shih Neng Yang Hui Ling Ko Fang Jen Lin 《Radiotherapy and oncology》2003,67(1):69-76
BACKGROUND AND PURPOSE: The potential risk of prolongation of treatment time in cervical cancer has been reported for many low-dose rate (LDR) studies, with an estimated loss of local control ranging from 0.3 to 1.6% per day of treatment prolongation. Since the treatment schedule for fractionated high-dose rate intracavitary brachytherapy (HDRICB) is not directly comparable with that for low-dose rate studies, this report aims to evaluate the adverse effect of treatment prolongation specifically for cervical cancer treated with HDRICB. MATERIAL AND METHODS: From September 1992 to December 1997, 257 patients diagnosed with uterine cervical cancer (35 Ib, 26 IIa, 122 IIb, 10 IIIa, 57 IIIb, 7 IVa), who underwent external radiotherapy combined with between two and four courses of HDRICB and a minimum of 3 years of follow-up (median 57 months), were analyzed. Treatment consisted of irradiation of the whole pelvis with 44-45 Gy consisting of 22-25 fractions by 5 weeks, with the dose boosted to 54-58 Gy (with central shielding) for patients diagnosed as FIGO stage IIb-IVa bilateral parametrial disease. HDRICB was performed using an Ir-192 remote afterloading technique at 1-week intervals. The standard prescribed dose for each course of HDRICB was 7.2 Gy to point A for three insertions (before July 1995), or 6.0 Gy to point A for four insertions (after July 1995). Total prescribed point A doses (external beam radiotherapy+HDRICB) ranged from 58 to 71.6 Gy (median, 65.6 Gy) for stage IB-IIA, while analogous dosage for larger lesions (stage IIb-IVa) ranged from 59 to 75.6 Gy (median, 65.6 Gy). Kaplan-Meier and multivariate analyses were used to test the effect of treatment time on pelvic control rate (PCR) and cause-specific survival (CSS) at 5 years. RESULTS: Median treatment time was 63 days. For all stages of disease, the 5-year CSS and PCR were significantly different comparing treatment times of less than and greater than or equal to 63 days [83% and 65% (P=0.004], 93% and 83% (P=0.02), respectively]. These associations were also significant for stage Ib/IIa [97% and 79% (P=0.01), and 100% and 87% (P=0.02), respectively), but not for stage IIb [75% and 72% (P=0.79), and 93% and 87% (P=0.83), respectively] or stage III [66% and 49% (P=0.2), and 83% and 72% (P=0.21), respectively]. Multivariate analysis identified three prognostic factors for CSS, stage (P<0.001), tumor response to external RT (P=0.001), and overall treatment time (OTT; P=0.006). Prognostic factors for pelvic failure were stage (P<0.001), tumor response to external RT (P=0.001), and OTT (P=0.03). Prolongation of treatment time resulted in a daily decrease in pelvic control rate of 0.67% overall, and 0.43% for stage Ib-IIa, 0.57% for stage IIb, and 0.73% for stage III patients. CONCLUSION: Analysis of the data from the current study demonstrates that the adverse effect of treatment prolongation was observed later in the treatment course for the high-dose rate (HDR) series compared to the LDR analog, however, treatment-time prolongation still negatively influenced the cause-specific survival and pelvic control rate for both dosage groups. 相似文献