全文获取类型
收费全文 | 5069篇 |
免费 | 270篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 143篇 |
妇产科学 | 64篇 |
基础医学 | 688篇 |
口腔科学 | 85篇 |
临床医学 | 299篇 |
内科学 | 1232篇 |
皮肤病学 | 47篇 |
神经病学 | 393篇 |
特种医学 | 147篇 |
外科学 | 967篇 |
综合类 | 22篇 |
预防医学 | 189篇 |
眼科学 | 139篇 |
药学 | 338篇 |
中国医学 | 13篇 |
肿瘤学 | 547篇 |
出版年
2023年 | 29篇 |
2022年 | 69篇 |
2021年 | 101篇 |
2020年 | 50篇 |
2019年 | 86篇 |
2018年 | 110篇 |
2017年 | 83篇 |
2016年 | 93篇 |
2015年 | 103篇 |
2014年 | 126篇 |
2013年 | 167篇 |
2012年 | 241篇 |
2011年 | 316篇 |
2010年 | 141篇 |
2009年 | 138篇 |
2008年 | 222篇 |
2007年 | 245篇 |
2006年 | 295篇 |
2005年 | 289篇 |
2004年 | 291篇 |
2003年 | 267篇 |
2002年 | 235篇 |
2001年 | 132篇 |
2000年 | 121篇 |
1999年 | 118篇 |
1998年 | 77篇 |
1997年 | 61篇 |
1996年 | 65篇 |
1995年 | 40篇 |
1994年 | 43篇 |
1993年 | 35篇 |
1992年 | 106篇 |
1991年 | 103篇 |
1990年 | 80篇 |
1989年 | 93篇 |
1988年 | 68篇 |
1987年 | 71篇 |
1986年 | 54篇 |
1985年 | 63篇 |
1984年 | 32篇 |
1983年 | 33篇 |
1982年 | 14篇 |
1981年 | 25篇 |
1980年 | 19篇 |
1979年 | 25篇 |
1978年 | 30篇 |
1977年 | 24篇 |
1973年 | 17篇 |
1970年 | 15篇 |
1968年 | 14篇 |
排序方式: 共有5371条查询结果,搜索用时 15 毫秒
1.
Byonggu An Yumi Zen Hiroya Akabori Naomi Kitamura Hiroyuki Ohta Akinori Otsuki Hiroo Mizuta Tomoyuki Tsujikawa Eiji Mekata 《Asian journal of endoscopic surgery》2021,14(1):120-123
A Bochdalek hernia (BH) is a congenital abnormality with incomplete closure of the diaphragm. It is usually manifested in infants but rarely in adults. Here, we report an adult patient with gastric volvulus and giant BH that were safely repaired by endoscopic reduction and elective laparoscopic surgery, respectively. A 79-year-old woman presented with left upper abdominal pain but no history of trauma. CT revealed a giant BH with gastric volvulus. After emergency endoscopic reduction of the volvulus, elective laparoscopic repair of the BH was performed. The 8 × 8-cm defect was repaired with interrupted nonabsorbable sutures and a mesh. The patient's postoperative course was uneventful, and no complications or recurrence were observed in the 6 months that followed. 相似文献
2.
A 1:1 adduct of methyl sorbate (MS) and 1,3‐di‐tert‐butylimidazol‐2‐ylidene (NHCtBu) initiates anionic polymerization of a nonconjugated polar alkene, allyl methacrylate (AMA) in toluene at ?20 °C. After the monomer is consumed quantitatively using a bulky aluminum Lewis acid, methylaluminum bis(2,6‐di‐tert‐butyl‐4‐methylphenoxide) (MAD), as an additive, successive ring‐closure occurs without highly dilute conditions to give a cyclic poly(AMA) containing α‐terminal MS unit, and an Mn of 8.8 × 103?58.5 × 103 with a narrow molecular dispersity index (Mw/Mn = 1.14–1.37). The lack of a need for dilution is due to the fact that an α‐terminal NHCtBu group is acting as the counter cation for the propagating center in the polymerization. From 1H NMR and matrix assisted laser desorption/ionization (MALDI‐TOF) mass spectra, combined with transmittance electron microscope (TEM) observation of a synthesized poly(AMA) with longer alkyl side chains prepared via a thiol‐ene click reaction, it is concluded that once the monomer is consumed, nucleophilic attack at the neighboring methine of the α‐terminal NHCtBu residue by the propagating anionic center causes ring‐closing to cyclic poly(AMA). 相似文献
3.
Kosuke Kaida Masaya Takahashi Torbj?rn Akerstedt Akinori Nakata Yasumasa Otsuka Takashi Haratani Kenji Fukasawa 《Clinical neurophysiology》2006,117(7):1574-1581
OBJECTIVE: The Karolinska sleepiness scale (KSS) is frequently used for evaluating subjective sleepiness. The main aim of the present study was to investigate the validity and reliability of the KSS with electroencephalographic, behavioral and other subjective indicators of sleepiness. METHODS: Participants were 16 healthy females aged 33-43 (38.1+/-2.68) years. The experiment involved 8 measurement sessions per day for 3 consecutive days. Each session contained the psychomotor vigilance task (PVT), the Karolinska drowsiness test (KDT-EEG alpha & theta power), the alpha attenuation test (AAT-alpha power ratio open/closed eyes) and the KSS. RESULTS: Median reaction time, number of lapses, alpha and theta power density and the alpha attenuation coefficients (AAC) showed highly significant increase with increasing KSS. The same variables were also significantly correlated with KSS, with a mean value for lapses (r=0.56). CONCLUSIONS: The KSS was closely related to EEG and behavioral variables, indicating a high validity in measuring sleepiness. SIGNIFICANCE: KSS ratings may be a useful proxy for EEG or behavioral indicators of sleepiness. 相似文献
4.
Effects of a newly introduced polyoxyethylene-modified superoxide dismutase (SOD-POE) on reperfusion induced arrhythmias were examined in the pentobarbital anesthetized rat. Reperfusion induced arrhythmias were elicited by occlusion of the left anterior descending coronary artery (LAD) for 15 min and subsequent release. The LAD occlusion was performed by compressing the artery using a suction cup of 2 mm in diameter placed on the LAD to which negative pressure was applied. The LAD occlusion and release was repeated at an interval of 30 min. SOD-POE or human SOD (h-SOD) (1000 U/kg) was injected intravenously 15 min prior to the occlusion at the second trial of the occlusion. In the control group, various types of arrhythmias including ventricular fibrillation (Vf), ventricular tachycardia (VT), premature ventricular contraction (PVC) and premature atrial contraction (PAC) were elicited immediately after release of the occlusion. In the SOD-POE-treated group, Vf and VT were completely prevented and the numbers of PVC and PAC significantly decreased, while pretreatment with h-SOD did not prevent the occurrence of reperfusion induced arrhythmias. The protective effects of SOD-POE lasted for more than 90-120 min. The plasma half life for SOD-POE was 10.8 hr, while that for h-SOD was 8.6 min. Results indicate that intravenous administration of SOD-POE would provide a new means of preventing reperfusion induced arrhythmias occurring in clinical situations. 相似文献
5.
6.
T Takatorige K Tatara K Kuroda N Nakanishi C Nishigaki E Okamoto N Nishi Y Nakagawa C Rin F Shinsho 《[Nihon kōshū eisei zasshi] Japanese journal of public health》1990,37(4):255-262
This study was done to identify factors affecting present hospitalization versus home care in 4,578 elderly subjects representing 87.1% of the elderly population living in S. city near Osaka. Subjects or their families were asked by interviews regarding the age of the subjects, the kind of persons living together in the family unit, the kind of housing, the number of rooms in the family dwelling, and health conditions. Subjects were also asked whether he or she could walk unassisted and whether home care would be preferred in case of an illness. Among the 153 hospitalized subjects, ability to walk, age, and the number of rooms were all significant factors, in decreasing order. Among the 1,193 persons who preferred home care in case of an illness, the number of rooms, age, ability to walk, and the size of the family unit were all significant factors, in decreasing order. Among subjects who could not walk unassisted, the number of rooms was the main factor determining their admission and not preferring home care if their condition worsened. Thus, although the ability to walk is the major factor among the factors we investigated, housing conditions are also important if home care is to be possible. 相似文献
7.
Masaki Hata Akinori Nango Hisateru Niki Yoshifumi Hayafune Atsushi Kato 《Journal of orthopaedic science》1997,2(1):3-9
To elucidate the growth of the tarsal bones in congenital clubfoot, relative to the growth of these bones in the unaffected feet and compared to growth in the feet of normal volunteers, we used a computed tomography (CT) scanner to measure the volume of all tarsal bones. The subjects of the study were 10 adults (7 men and 3 women) with unilateral congenital clubfoot (average age 20 years and 1 month). As controls, we examined 11 healthy volunteers. We calculated the ratio of the volume of each tarsal bone to the total bone volume and the ratio of the volume of each tarsal bone in clubfoot to the corresponding bone in the unaffected foot. The volume ratio of each tarsal bone was compared between clubfeet and unaffected feet because the differences of each tarsal bone ratio between the normal foot group and unaffected foot group were not significant. In the clubfeet (n=10), the talus and the medial cuneiform bones were smaller than those in the unaffected feet (n=10) but the cuboid bone was larger. The growth of the navicular did not differ from as that in unaffected feet. Our results suggested hypoplasia on the medial side of the foot in adult patients with congenital clubfoot. The 3 patients who had undergone medial release showed particularly marked hypoplasia of the medial side. In congenital clubfoot cases with severe deformities who had undergone wide soft-tissue release operations, there were clear growth suppressions in the talus and the medial cuneiform. We could not determine whether the cause of the growth suppression was the hypoplastic nature of tarsal bones themselves or the surgical obstacles to tarsal bone growth. 相似文献
8.
Electron-microscopic and immunohistochemical study of beta-2-microglobulin-related amyloidosis. 总被引:1,自引:0,他引:1
beta 2-Microglobulin (beta 2-MG)-related amyloidosis has been reported as a complication in long-term hemodialysis patients. We observed beta 2-MG amyloid deposits in synovial sheaths, bone cysts and gastric mucosa. They showed unique ultrastructural features, that is bundles or nodules consisting of curved or linear amyloid fibrils, associated with various cell reactions. The electron-microscopic histochemical study showed that they strongly stained with periodic acid-silver methenamine stain. A similar phenomenon was noticed in the spicules or bundles of amyloid fibrils in primary and secondary renal amyloidosis. With the cationic reagent toluidine blue 0, proteoglycan-like structures were observed around amyloid bundles and nodules, but not on each fibrils. Based on these results, we postulate that there is a close relationship between ultrastructural features and histochemical characteristics in beta 2-MG amyloid fibrils. 相似文献
9.
Hiroyuki Yamamoto Fumio Itoh Akinori Senota Yasushi Adachi Mitsuru Yoshimoto Takao Endoh Yuji Hinoda Akira Yachi Kohzoh Imai 《Journal of clinical laboratory analysis》1995,9(5):297-301
The matrix metalloproteinase matrilysin (MMP-7) is a member of the matrix metallo-proteinase gene family, which is believed to play an important role in tumor invasion and metastasis. We have previously found that matrilysin mRNA is specifically expressed in colorectal cancers and adenomas and that its message is localized in the tumor cells themselves. We examined the effects of activated Ki-ras oncogene on the expression of matrilysin in colon cancer cells. We showed that both mRNA and the enzymatic activity of matrilysin were induced by the introduction of activated Ki-ras into SW1417 colon cancer cells. To understand the mechanisms regulating this induction, we analyzed alterations of AP-1 activity induced by activated Ki-ras, using the chloramphenicol acetyltransferase assay. AP-1 activity in SW1417 cells expressing activated Ki-ras was higher than that in control cells. The gel-shift assay also showed higher levels of AP-1 binding protein in SW1417 cells expressing activated Ki-ras than those in control cells. Our results suggest that activated Ki-ras may play a role in inducing expression of matrilysin through an AP-1-dependent pathway in colon cancer cells. 相似文献
10.
The utilization of radical operation in gastric cancer cases has led to the development of various operation techniques. With the improvement in perioperative management it can be said that age no longer is a restriction. A study of gastric cancer prognosis indicates an upward trend in survival since 1960 along with the increased detection of early cancer. This suggests the most importance of early detection in increasing the therapeutic results obtained in cases of gastric cancer. In cases with advanced cancer, 5-year survival rate of 44.7 per cent was attained through such aggressive actions as extended dissection of lymph nodes and combined resection of surrounding organs with evaluation of the macroscopic classification of the cancer. 相似文献